Medicine

OPEN

Comprehensive analyses of cuproptosis-related gene CDKN2A on prognosis and immunologic therapy in human tumors

Di Zhang, MMa,b (D, Tao Wang, MDa,b, Yi Zhou, MDa,b, Xipeng Zhang, MDa,b,c,*[D

Abstract

Recent studies have identified a novel programmed cell death based on copper, named cuproptosis. However, as an anti- cuproptosis gene, the functional roles, definite mechanisms and prognostic value of CDKN2A in pan-cancer are largely unclear. The GEPIA2, cancer genome atlas (TCGA), the tumor immune estimation resource 2.0 and CPTAC databases were performed to validate the differential expression of CDKN2A in 33 tumors. The clinical features and survival prognosis analysis were conducted by GEPIA2 and UALCAN web tool. Genetic alteration analysis of CDKN2A in pan-cancer was also evaluated. Furthermore, the functional roles of CDKN2A were explored via DNA methylation analysis, tumor microenvironment, infiltration of immune cells, enrichment analysis and gene co-expression associated with cuproptosis and immune regulation. The CDKN2A expression, both at the transcriptional and translational level, was obviously upregulated in most cancer patients, which might lead to poor survival in certain cancer types. CDKN2A expression was significantly associated with tumor pathological stages in some cancer types. In adrenocortical carcinoma (ACC) and kidney renal clear cell carcinoma (KIRC), DNA methylation of CDKN2A was explored to induce poor clinical outcomes. Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis indicated that CDKN2A expression was closely related to several cancer-associated signaling pathways, such as the p53 signaling pathway, Cellular senescence, DNA replication and Cell cycle signaling pathways. Gene set enrichment analysis (GSEA) analysis suggested that aberrantly expressed CDKN2A took part in the cell cycle regulation, immune regulation and mitochondrial signaling pathways in certain cancer patients. In addition, aberrant CDKN2A expression was closely correlated to immune infiltration and the levels of immune-regulatory genes. The study deeply defined the concrete roles of cuproptosis-related gene CDKN2A in tumorigenesis. The results provided new insights and pieces of evidence for treatment.

Abbreviations: ACC = adrenocortical carcinoma, BLCA = bladder urothelial carcinoma, BRCA = breast invasive carcinoma, CAF = cancer-associated fibroblasts, CC = cellular component, CDKN2A = cyclin dependent kinase inhibitor 2A, CESC = cervical squamous cell carcinoma and endocervical adenocarcinoma, COAD = colon adenocarcinoma, DFS = disease-free survival, GBM = glioblastoma multiforme, GEPIA2 = gene expression profiling interactive analysis, GO = gene ontology, GSEA = gene set enrichment analysis, HNSC = head and neck squamous cell carcinoma, KEGG = Kyoto encyclopedia of genes and genomes, KICH = kidney chromophobe, KIRC = kidney renal clear cell carcinoma, KIRP = kidney renal papillary cell carcinoma, LIHC = liver hepatocellular carcinoma, LUAD = lung adenocarcinoma, OS = overall survival, OV = ovarian serous cystadenocarcinoma, PAAD = pancreatic adenocarcinoma, SKCM = skin cutaneous melanoma, TGCT = testicular germ cell tumors, THCA = thyroid carcinoma, THYM = thymoma, UCEC = uterine corpus endometrial carcinoma.

Keywords: cuproptosis, CDKN2A, pan-cancer, immunotherapy, prognosis

1. Introduction

Due to its rapidly increased incidence and mortality, cancer is a major public health problem and a barrier to prolonging life expectancy.[1,2] The highly intricate process of tumorigene- sis and poor prognosis pose a great threat to cancer therapy.[1]

Therefore, it is urgent to explore in-depth the definite mecha- nisms and elucidate the expression of relevant genes related to tumor occurrence so that the results provided new directions for diagnosis and treatment.

Programmed cell death is vital to the homeostasis of body tis- sues.[3] At present, more types of cell death, such as necroptosis,

The authors have no funding and conflicts of interest to disclose.

The datasets generated during and/or analyzed during the current study are publicly available.

The study protocol complied with the Declaration of Helsinki. The work described has not been submitted elsewhere for publication, in whole or in part, and all authors listed have approved the manuscript that in enclosed.

Supplemental Digital Content is available for this article.

a Department of Colorectal Surgery, Tianjin Union Medical Center, Tianjin, China,

b Tianjin Institute of Coloproctology, Tianjin, China ” The Institute of Translational Medicine, Tianjin Union Medical Center of Nankai University, Tianjin, China.

*Correspondence: Xipeng Zhang, Department of Colorectal Surgery, Tianjin Union Medical Center, 300121, Tianjin, China (e-mail: zhxp0813@163.com).

Copyright @ 2023 the Author(s). Published by Wolters Kluwer Health, Inc. This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial License 4.0 (CCBY-NC), where it is permissible to download, share, remix, transform, and buildup the work provided it is properly cited. The work cannot be used commercially without permission from the journal.

How to cite this article: Zhang D, Wang T, Zhou Y, Zhang X. Comprehensive analyses of cuproptosis-related gene CDKN2A on prognosis and immunologic therapy in human tumors. Medicine 2023;102:14(e33468).

Received: 19 December 2022 / Received in final form: 10 March 2023 / Accepted: 16 March 2023

http://dx.doi.org/10.1097/MD.0000000000033468

pyroptosis and ferroptosis, have been found and identified.[4-6] It is reported that cell death is tightly involved in tumorigen- esis and prognosis.[7] Therefore, striking cell death might be a latent strategy for tumor therapy. Cuproptosis, arising from copper-mediated mitochondrial proteotoxic stress, is a newly identified form of regulatory cell death.[8] The process was veri- fied that the lipoyl moiety of increased lipoylated TCA enzyme bound to copper, which induced proteotoxic stress character- ized by lipoylated protein aggregation, decreased Fe-S cluster- containing proteins and increased HSP70.[8] Several studies have recognized the crucial roles of copper and cuproptosis modu- lated by copper in living things, such as the liver,[9] lung,[10] and other tissues.[8,11] A total of 12 genes were verified to take part in the cuproptosis pathway, consisting of 7 pro-cuproptosis genes (ferredoxin 1, dihydrolipoamide dehydrogenase, dihy- drolipoamide S-Acetyltransferase, lipoic acid synthetase, homo sapiens lipoyltransferase 1, pyruvate dehydrogenase E1 sub- unit Alpha 1 and pyruvate dehydrogenase E1 subunit beta), 3 anti-cuproptosis genes (CDKN2A, glutaminase and metal regu- latory transcription factor 1), and 2 transporters for copper-sol- ute carrier family 31 member 1 and ATPase copper transporting beta.[12]

Cyclin dependent kinase inhibitor 2A (CDKN2A), serving as a tumor suppressor and cell cycle regulator, has been eluci- dated in some cancers, such as glioblastoma (GBM),[13] follic- ular lymphoma,[14] and colorectal cancer (CRC).[15] Disruption of CDKN2A (deletion or methylation) has been reported to be a frequent event in tumorigenesis, which affects the clinical characteristics and patient outcomes.[14-16] A meta-analysis from Xing showed that CDKN2A hypermethylation was significantly associated with unfavorable prognosis in CRC patients.[15] Alhejaily and his colleagues revealed that silence of CDKN2A by deletion or methylation was correlated with worse clinical outcome in follicular lymphoma.[14] Similar results were also found in pancreatic ductal adenocarcinoma (PDAC), thymic car- cinoma, head and neck squamous cell carcinoma (HNSC) and muscle invasive bladder cancer (MIBC).[16-19] Although the tum- origenic effects of disruption of CDKN2A were well confirmed, unexpectedly high CDKN2A indicated a poor clinical outcome in some cancer, including Colon adenocarcinoma (COAD), Bladder Urothelial Carcinoma (BLCA) and Liver hepatocellular carcinoma (LIHC).[17,20-22] The mechanism by which CDKN2A serves as a tumor suppressor but results in unfavorable prog- nosis is speculated that CDKN2A may involve in cuproptosis activity.[23-25] Nevertheless, as an anti-cuproptosis gene, the roles or signatures and the regulatory mechanisms of CDKN2A in pan-cancer have not yet been explored in depth.

In this study, a comprehensive analysis of CDKN2A expres- sion in 33 cancer types was performed. In detail, aberrantly expressed genes and protein analysis, survival rate, methylation analysis and enrichment analysis were carried out. The correla- tion between CDKN2A expression and immune infiltration was followed explored. Lastly, the association between CDKN2A expression and gene related to immune regulation or cupro- ptosis was studied. The results explored the predictive value of CDKN2A and provided new insight into cancer therapy.

2. Methods

2.1. CDKN2A differential expression analysis

The Tumor Immune Estimation Resource (https://cistrome.shin- yapps.io/timer/)[26] and Gene Expression Profiling Interactive Analysis (GEPIA2, http://gepia2.cancer-pku.cn/#analysis)[27] were applied to compare the CDKN2A expression in pan-cancer and their corresponding paracancerous tissue samples with the threshold of P value < . 05 and ILog2FCI > 1. The total protein level of CDKN2A between normal tissues and ten cancer sam- ples (kidney renal clear cell carcinoma [KIRC], uterine corpus endometrial carcinoma [UCEC], lung adenocarcinoma [LUAD],

HNSC, LIHC, breast cancer, ovarian cancer, COAD and pan- creatic adenocarcinoma [PAAD]) was analyzed by the “CPTAC analysis” module in the UALCAN database (http://ualcan.path. uab.edu)[28] and immunohistochemical (IHC) staining down- loaded from “The Human Protein Atlas” database. The GEPIA2 database was performed to investigate the clinic correlation of CDKN2A expression.

2.2. Survival analysis in pan-cancer

The prognostic value of CDKN2A, including overall survival (OS), disease-free survival (DFS), disease-specific survival and progress-free interval, were determined by GEPIA and Xiantao bioinformatics toolbox (https://www.xiantao.love) tool accord- ing to the Kaplan-Meier analysis between high-expression and low-expression groups. We performed GEPIA2 to examine the relationship between CDKN2A expression and OS and DFS. The heatmap data and survival curve were displayed. Xiantao toolbox was carried out to analyze TCGA data of pan-cancer. Forest plots and Kaplan-Meier curves were drawn to explore the effect of CDKN2A expression on disease progression. Furthermore, the frequency, type, and site information related to mutation of CDKN2A in pan-cancer were analyzed by cBio- Portal (https://www.cbioportal.org/).[29]

2.3. Genetic alteration analysis of CDKN2A in pan-cancer

The genetic alteration, including mutation type, alteration fre- quency and the copy number alteration (CNA), of CDKN2A was performed by cBioPortal tool. The mutation site with highest change frequency was visualized in the 3D structure of CDKN2A protein.

2.4. Immune infiltration analysis

The association between CDKN2A expression and immune infiltration in pan-cancer was explored by using the “Immune” module of TIMER (http://timer.cistrome.org/).[26] We applied 7 algorithms, exactly, MCPCOUNTER, CIBERSORT, CIBERSORT-ABS, EPIC, QUANTISEQ and XCELL, to analyze the infiltration of tumor-infiltration immune cells, such as mac- rophages (including M0, M1 and M2) and cancer-associated fibroblasts (CAF). Heat maps and scatter plots were displayed according to the TCGA data.

2.5. Methylation analysis

The effect of DNA methylation on CDKN2A expression in some cancers was explored based on TCGA databases by the “Methylation” module of the xiantao bioinformatics toolbox. The “MethSurv” web tool (https://bit.cs.ut.ee/methsurv/)[30] was carried out to further excavate the correlation between CDKN2A methylation and patients’ survival. Kaplan-Meier plots were drawn for visualization.

The Protein-Protein Network Interaction network was con- structed based on the STRING website, and the top 20 experimental identified CDKN2A-binding molecules were ana- lyzed by Cytoscape. Gene ontology (GO) and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analysis about selected genes were performed by the xiantao bioin- formatics toolbox. GO [including biological process, cellular component (CC) and molecular function], and KEGG analy- sis were visualized by the xiantao bioinformatics toolbox and bioinformatics website (http://www.bioinformatics.com.cn/). GEPIA2 tool was carried out to explore similar genes related

to CDKN2A. TCGA data in pan-cancer were downloaded. Gene Set Enrichment Analysis (GSEA) and correlation analy- sis was performed via the xiantao bioinformatics toolbox to uncover relevant pathways affected by CDKN2A expression in pan-cancer. INESI >1, adjust P value < . 05 and FDR < 0.25 were considered as obviously enriched.

2.7. Statistical analysis

In TIMER 2.0, the statistical significance calculated by the Wilcoxon test is annotated by the number of stars. The ANOVA method was carried out to compare the tumor and all normal samples. The Kaplan-Meier method was utilized to assess the relationship between prognosis versus CDKN2A expression, mutation or methylation levels. The Pearson rank correlation coefficient was used to explore the association between the 2 groups. A P value <. 05 was considered statisti- cally significant.

3. Results

3.1. Aberrant expression of CDKN2A in pan-cancers

The CDKN2A expression in pan-cancer and paracancerous tis- sue samples was analyzed by the TIMER database. As displayed in Figure 1A, CDKN2A was dramatically higher expressed in cancer tissues than in paracancerous tissue samples, such as BLCA, Breast invasive carcinoma (BRCA), Cholangiocarcinoma, COAD, HNSC, Kidney Chromophobe (KICH), KIRC, Kidney renal papillary cell carcinoma (KIRP), LIHC, LUAD, Lung squa- mous cell carcinoma, Prostate adenocarcinoma (PRAD), Rectum adenocarcinoma, Stomach adenocarcinoma, Thyroid carcinoma (THCA) and UCEC. Furthermore, the TCGA and GTEx data from GEPIA2 were integrated to analyze CDKN2A expression

in some cancers lacking paracancerous normal tissues. The results indicated that the CDKN2A expression in cancer sam- ples, respectively, Adrenocortical carcinoma (ACC), Cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC), Lymphoid Neoplasm Diffuse Large B-cell Lymphoma, Acute Myeloid Leukemia, Brain Lower Grade Glioma, Ovarian serous cystadenocarcinoma (OV), PAAD, Pheochromocytoma and Paraganglioma (PCPG), Sarcoma, Thymoma (THYM) and Uterine Carcinosarcoma was obviously upregulated (Fig. 1B). Instead, CDKN2A was significantly downregulated in Testicular Germ Cell Tumors (TGCT) tissues (Fig. 1B). We further accessed the DCKN2A protein levels and IHC staining in various cancers. The “CPTAC analysis” results showed that the total expres- sion of CDKN2A was dramatically elevated in KIRC (Fig. 2A), UCEC (Fig. 2C) and LUAD (Fig. 2E), and decreased in HNSC (Fig. 2G) and LIHC (Fig. 2I). There was no significant change in Breast cancer (Fig. 2K), Ovarian cancer (Fig. 2M), Colon can- cer (Fig. 20) and PAAD samples (Fig. 2Q). Consistent with the “CPTAC analysis” results, stronger IHC staining was discov- ered in UCEC (Fig. 2D) and LUAD (Fig. 2F). Contrary to above protein expression results, IHC staining showed that CDKN2A expression was increased in LIHC tissues (Fig. 2J), with no statis- tical significance in KIRC (Fig. 2B), HNSC (Fig. 2H) and PAAD (Fig. 2R) tissues. Besides, IHC staining results also indicated the increased expression in breast cancer (Fig. 2L), Ovarian cancer (Fig. 2N) and Colon cancer (Fig. 2P).

3.2. Correlation between CDKN2A expression and tumor pathological stage in pan-cancer

The GEPIA2 tool was used to elucidate the relationship between CDKN2A and clinical information. Figure 1C indi- cated that 9 cancers had a stage-specific change of CDKN2A,

Figure 1. Differential expression of CDKN2A in pan-cancers. (A) mRNA levels of CDKN2A in pan-cancers and their corresponding normal samples performed by TIMER2 database. (B) CDKN2A expression from GEPIA2 database. (C) Correlation analysis of CDKN2A expression and tumor pathological stage. CDKN2A = cyclin dependent kinase inhibitor 2A, GEPIA2 = gene expression profiling interactive analysis.

A

C

F value = 3.08

CDKNZA Expression Level (log2 TFM)

F value = 4.95 Pr(>F) = 0.00234

F value = 6.76

100

ACC

Pr(MF) = 0.0329

-

COAD

KICH

-

Pr(F) = 0.000509

.

0

75

.

+

.

U

2

25

~

1

0.0

ADC. Tumar- BLCA.Tumor

DI RIC Tumor-

UMC Normal-

LUSC Normal-

OM.Tomar

PCPO. IN

UVM. Tumor-

Stage I

Stage II

Stege !!!

Stage IV

Stage1

Stage II

Stage II

Stage IV

Stage I

Stage II

Stage IN

Stage IV

BLCA Normal

BRCANOTTE

BRCA-Hez. Tumor

BRCA-Luminal. Tumor

CESC.Tumor CHOL Tung

DLBIC. Tumor

ESCA. Tumor

ESCA Normal

GEM Tunge

HNSC Normal

HNSC-HPVpos. Tumor

HNSC-HPVneg. Tumor

KIDH. Temor

KICH Normal

KIRC Tumar

KIRP.Tumor

KRP Normal

LAML. Tumor

LGG.Tumor

LIHC Tumor

MESO. Tumor

PRAD Normal

READ. Tumor

READ Normal

SARC. Tumor

STAD Normal

TGCT.Tumor

THICA.Tumor

THCA Normal

vat Tumor

UČST UCS. Tumor

10

UCEC

F value = 3.24 Pr[>F) = 0.0234

2

KIRC

F value = 3.74 Pr[>F) = 0.0112

KIRP

F value = 4.58

Pr(>F) = 0.00381

.

B

-

0

0

.

-

-

.

.

.

-

2

.

0

Stage I

Stage II

Stage II

Stage IV

Stage l

Stage Il

Stage Ill

Stage IV

Stage 1

Stage #1

Stage ili

Stage IV

-

-

LIHC

F value = 9.08

F value = 11.4 Pr(>F) = 2.940-07

Pr[>F) = 8.430-06

THCA

.

4

.

lunchje?P.sund()-/125)

CSC

DLAC

LAMM

100

-

=

.

-

4

n

.

¥

2

0

.

Stage 1

Stage Il

Stage !!!

Stage IV

Stage I

Stage II

Stage II

Stage IV

-

BRCA

F value = 2.39 PrP>F) = 0.0492

.

2

PCPG

SARG

DOCT

THYM

UGs

-

6

+

-

0

Stage 1

Stage II

Stage ml

Stage IV

Stage X

Figure 2. CDKN2A protein expression in pan-cancer. Protein levels of CDKN2A between normal samples and KIRC (A), UCEC (C), LUAD (E), HNSC (G), LIHC (I), breast cancer (K), ovarian cancer (M), Colon cancer (O) and PAAD (Q) samples were identified by "CPTAC analysis" module in the UALCAN database. Immunohistochemical (IHC) staining of CDKN2A protein in pan-cancer was downloaded from "The Human Protein Atlas" database. IHC staining of CDKN2A and their quantification in KIRC (B), UCEC (D), LUAD (F), HNSC (H), LIHC (i), breast cancer (L), ovarian cancer (N), Colon cancer (P) and PAAD (R) samples tissues were displayed. CDKN2A = cyclin dependent kinase inhibitor 2A, KIRC = kidney renal clear cell carcinoma, HNSC = head and neck squamous cell carcinoma, LIHC = liver hepatocellular carcinoma, LUAD = lung adenocarcinoma, PAAD = pancreatic adenocarcinoma, UCEC = uterine corpus endometrial carcinoma.

A

B

KIRC

5-

P=0.0914

Protein expresuint af CDANJA is Car sail ACC

4.

Median: @

Medan: 2.294

%Area

3

2.

1

P=3.096E-11 =

0

-

Normal

Tumor

C

D

UCEC

Medianc @

15

Median: 0417

%Area

10

5

P=2.229E-06

=

0

E

F

Normal

Tumor

Protein expression of CDKNZA in Lung adenocarcinoma

LUAD

Median: - 4.013

15-

**

Median: - 4.108

%Area

10

5

P=1.197E-02

0

G

=

OFTHE samples

H

Normal

Tumor

Protrin expression of CDKNŽA in Head and neck squamous

HNSC

Medianc -4.835

20

p=0.3430

Median: D.45

15-

%Area

10

5-

P=1.292E-02

=

J

0

CPEAC sangies

Normal

Tumor

Potrin expersion of CDANZA in Hepatocellular carcinoma

LIHC

Median: 4.013

Median: 0.001

2.5

2.0

-

%Area

1.5

1.0

0.5

P=1.922E-02

=

0.0

K

COPIAĆ tungtes

L

Normal

Tumor

Protein expression of ČEKZa in Breast cancer

breast cancer

Median: 4.826

4-

Median: 4.056

Q

3

%Area

2

1

P=0.5997

0

Normal

Tumor

M

=

OPTIC cangini

N

Protein expression of CORNZA In Ovarian cancer

Ovarian cancer

Median: 4.002

15-


Median: 4.375

%Area

10

5-

P=0.1337

=

0

O

OPTIC sengin

P

Normal

Tumor

Protein expression of CDKNIA in Colon cancer

Colon cancer

Median: 0.005

25-

**

Median: 4.351

20-

%Area

15

10

5-

P=0.0930

0

Q

=

R

Normal

Tumor

OFTAC Langles

Protein expressions of CDKNZA in Funcritic adenocarcinoma

Pancreatic adenocarcinoma

Median: 6.874

Median :- 4.044

4-

p=0.8890

:

-

3-

%Area

N

P=0.4324

1

=

0

CPTAC sangles

Normal

Tumor

including ACC, COAD, KICH, UCEC, BRCA, KIRC, KIRP, LIHC, and THCA. In other tumor types, there was no obvi- ous correlation between CDKN2A and pathological stage (see Figure S1, Supplemental Digital Content 1, http://links.lww. com/MD/I754, Supplemental Content, which demonstrates the CDKN2A expression through different pathological stages in some cancers).

3.3. Prognostic value of CDKN2A in cancer patients

The potential role of CDKN2A in prognosis was assessed by the GEPIA2 tool. As displayed in Figure 3A, the results indi- cated that CDKN2A expression was negatively related to OS of ACC (P = . 011), COAD (P = . 013) and LIHC (P = . 0049). Moreover, high expression of CDKN2A predicted poor DFS in ACC (P = . 03, Fig. 3B), COAD (P = . 0066, Fig. 3B), KIRC (P = . 026, Fig. 3B), LIHC (P = . 003, Fig. 3B), PRAD (P = .0049, Fig. 3B), skin cutaneous melanoma (SKCM) (P = . 028, Fig. 3B), THCA (P = . 012, Fig. 3B) and UCEC (P = . 018, Fig. 3B), while high CDKN2A predicted better DFS in GBM (P = . 014, Fig. 3B).

The results of Cox regression model indicated that CDKN2A expression may play adverse roles in the OS of ACC (P < . 001, Fig. 4A), COAD (P = . 002, Fig. 4A), KICH (P = . 019, Fig. 4A), LIHC (P = . 003, Fig. 4A), THCA (P = .007, Fig. 4A) and UCEC (P < . 001, Fig. 4A), but protective roles in HNSC (P = . 004, Fig. 4A) and ESCC (Esophageal Squamous Cell Carcinoma, P = . 022, Fig. 4A). Consistent with the Cox regression results, Kaplan-Meier curve showed that CDKN2A expression was negatively related to OS in ACC (P = . 006, Fig. 4A), COAD (P = . 007, Fig. 4A), LIHC (P = . 001, Fig. 4A), and UCEC (P <. 001, Fig. 4A). There was no clear correlation between CDKN2A levels and the outcomes of KICH, THCA, HNSC, and ESCC patients (see Figure S2A, Supplemental Digital Content 2, http://links.lww.com/ MD/I755, Supplemental Content, which indicated the effect of CDKN2A on disease outcomes). For disease-specific sur- vival, in accord with Cox regression, Kaplan-Meier analysis showed that high level of CDKN2A predicted poor outcome in ACC (P = . 01, Fig. 4B), COAD (P = . 001, Fig. 4B), KIRC (P = . 015, Fig. 4B), LIHC (P = . 02, Fig. 4B) and UCEC (P < .001, Fig. 4B). For HNSC and KICH patients, the survival

Figure 3. Prognostic assessment of CDKN2A level in OS and DFS. Kaplan-Meier analysis of OS (A) and DFS (B) in patients with low and high CDKN2A. The low-expression and high-expression cohorts were divided according to the thresholds with low cutoff (50%) and high cutoff (50%) values. P value < . 01 and | logFC| > 1 were cutoff values. CDKN2A = cyclin dependent kinase inhibitor 2A, DFS = disease free survival, OS = overall survival.

A

0.5

ACC

BLCA

BRCA

CESC

CHOL

COAD

DLBC

ESAD

GBM

HNSC

KICH

KIRC

KIRP

LAML

LGG

LIHC

LUAD

LUSC

OV

PAAD

PRAD

READ

SARC

SKCM

STAD

TGCT

THCA

THYM

UCEC

UCS

0

Overall Survival

Overall Survival

Overall Survival

=

L

Low CDKN2A Group

=

Low COKN2A Group

1.0

High CURTOA Group Logrank pao.co.re

High CORNZA Group

Low COKN2A Group

0.8

Logrank pa0.011

High CORNZA GROUD

0.8

Hola

HR(high)=1.9

0.8

HR(high)=1.7

Percent survival

P(HR)=0.011 nghigh)=38

Percent survival

P(HRI0.013

nonight#1.35 m(lo=)=135

Percent survival

P(HR)-0.0049

06

0.6

nhg12 njom)=182

0.5

0.4

0.4

0.4

2

0.2

DUO

0.0

0.0

0

50

100

150

0

50

100

150

0

20

40

60

80

100

120

Months

Months

Months

B

Disease Free Survival

Disease Free Survival

2

a

Disease Free Survival

Disease Free Survival

Disease Free Survival

2

Low COINZA Group

Low COKNZA Group

Low CORNZA Group

:

Ow COKNDA Group

=

LOW COKINZA Group CORNZA GROUP

Logrank pr0.027

Toorank 000 013

varhijab to

LA CRO

HER NiOh)=1.6

Locrank BRO 008

Logrank pm0 016

0.8

Hinon,2 1

DIHRJ-0 03

BORDO

PARIS

0.8

haben

highas 182 n(high) nílow)=182

HR(high)=1.3.

P(HR)=0 028

0.8

HR(high)=2.3

Percent survival

n(high)=38 now)=38

Percent survival

miow)=81

Percent survival

Percent survival

n(high):228

Percent survival

p(HR)-0 018 n(high)=86

0.6

0.5

0.6

0.6

ngow)=229

0.6

now)-06

0.4

0.4

0.4

0.4

0,4

3

3

0.2

0

8

:

3

O.D

0

50

100

150

8

0

Months

0

10

20

30

40

50

0

20

40

60

BO

100

120

Month

Months

0

100

200

300

0

20

40

60

80

100

120

140

Months

Months

.

0.6

0.3

ACC

BLCA

BRCA

CESC

CHOL

COAD

DLBC

ESAD

GBM

HNSC

KICH

KIRC

KIRP

LAML

LGG

LIHC

LUAD

LUSC

OV

PAAD

PRAD

READ

SARC

SKCM

STAD

TGCT

THCA

THYM

UCEC

UCS

0

Disease Free Survival

Disease Free Survival

Disease Free Survival

Disease Free Survival

10

Low CONTA CTOUP

10

LOW CONTA OrOUP

1.0

Low CDKONZA Group

1.0

Low COKNDA Group

Logrank p=0 0057

LograrA PHO 023

Logrank PRO 0043

0.8

Han bat

Da

D.8

Percent survival

DOHR)-0 004 nhighi=135 mow)= 135

Percent survival

nghigh=258

Percent survival

p(HR)=0.0049 n(high)-246

0.8

POURHO 615

0.6

0.6

)-246

Percent survival

0.6

0.8

now)-255

0.4

0.4

0.4

0.4

02

0.2

0.2

0.2

00

00

0.0

00

0

50

100

150

0

20

40

00

0

100

120

140

Months

Months

Q

50

100

150

0

50

100

150

Months

Months

CharacteristicsN (%)HR (95% CI)P value
ACC791.844 (1,312-2.593)<0.001
BLCA4130.986 (0.923-1.054)0.683
BRCA10820.925 (0.809-1.056)0.249
CESC3060.964 (0.800-1.162)0.701
CHOL361.001 (0.607-1.652)0.996
COAD4771.288 (1.094-1.516)0.002
DLBC480.875 (0.478-1.602)0.666
ESAD801.032 (0.825-1.291)0.784
ESCC820.758 (0.598-0.960)0.022
GBM1680.959 (0.882-1.042)0.322
HNSC5010.906 (0.846-0.969)0.004
KICH641.958 (1.117-3.433)0.019
KIRC5391.280 (0.948-1.729)0.107
KIRP2881.425 (0.952-2.134)0.086
LAML1401.103 (0.847-1.435)0.458
LGG5270.914 (0.763-1.094)0.320
LIHC3731.251 (1.081-1.447)0.003
LUAD5261.081 (0.988-1.184)0.091
LUSC4960.995 (0.924-1.072)0.901
OV3770.953 (0.892-1.017)0.147
PAAD1780.986 (0.850-1.145)0.855
PRAD4992.152 (0.871-5.313)0.097
READ1661.285 (0.882-1.871)0.192
SARC2630.982 (0.882-1.093)0.741
SKCM4560.978 (0.904-1.059)0.588
STAD3702.075 (0.363-11.876)0.412
TGCT1393.290 (0.634-17.001)0.156
THCA5101.893 (1.193-3.005)0.007
THYM1181.279 (0.597-2.738)0.527
UCEC5511.284 (1.152-1.432)<0.001
UCS560.981 (0.746-1.291)0.894

A

Cancer: ACC

Cancer: COAD

1.0 -

CDINZA

1.0 -

CDKNIA

Low

Low

High

High

0.8

0.8

Survival probability

Survival probability

0.6

0.6

0.4

0.4

0.2

Overall Survival HR -3.19(1.40-7.26)

0.2

Overall Survival

HR-1.72 (1.16-2.56)

0.0

P=0.006

0.0

P = 0:007

.

50

100

150

0

50

100

150

Time (months)

Time (months)

Cancer: LIHC

Cancer: UCEC

1.0-

CDKNIA

1.0 -

CDKNIA

Layw

Low

High

High

0.8

0.8

Survival probability

Survival probability

0.6

0.6

0.4

0.4

0.2

Overall Survival

0.2

1EX-1.78 (1:25-2 52)

Ovenil Survival

HER - 2 30(1.50-3.53)

2

3

0.0

P = 0.001

0.0

P < 0.001

0

30

60

90

120

0

50

100

150

200

B

Time (months)

Time (months)

Cancer: ACC

Cancer: COAD

Cancer: LIHC

1.0

CDKNZA

1.0-

CDKNIA

10-

CDKNZA

Low

Low

Low

High

High

High

0,8

0.8

0.8

Survival probability

Survival probability

Survival probability

0,6

0.6

0.6

0.4

0.4

0.4

0.2

Disease Specifie Survival HR - 2:98 41.29-6.89)

0.2

Discase Specific Survival HR - 2.39(1.41-4.04)

0.2

Disease Specific Survival

HE-170(1.88-268)

0.0

P-001

0.0

P=0.001

0.0

P =0.02

0

50

100

150

0

50

100

150

0

30

60

90

120

Time (months)

Timc (months)

Time (months)

Cancer: KIRC

Cancer: UCEC

1.0 -

FGL2

1.0 -

CDKNZA

Low

+ Low

High

10gh

0.8

Survival probability

0.8

Survival probability

0.6

0.6

0.4

0.4

0.2

Disease Specific Survival HR - 0.62 (0 43-0.91)

0.2

Disease Specific Survival

3

HR - 2.98 (1,72-5.15)

1

2

0.0

P-0015

0.0

P < 0:001

0

50

100

150

0

50

100

150

200

C

Time (months)

Time (months)

Cancer: ACC

Cancer: COAD

Cancer: UCEC

1.0

J

CDKNZA

1.0 -

CDKNIA

1.0 -

CDKNIA

Low

Low

High

High

Low

High

0.8

0.8

Survival probability

0.8

Survival probability

Survival probability

0.6

0.6

0.6

0.4

0.4

0.4

0.2

Progress Free Interval

0.2

Progress Free Interval

0.2

HR -2.67(1.39-5.13)

HR-1.59(1.12-2.26)

Progress Free lanerval

HR - 2.11 (1,47-3.03)

0,0

₱=0:003

0.0

P-001

0.0

₱€ 0.001

0

50

100

150

0

50

100

150

0

50

100

150

200

Time (months)

Time (months)

Time (months)

Cancer: KIRC

Cancer: PRAD

Cancer: LIHC

1.0

FGL2

1.0 -

CDKNZA

1.0 - J

CDKNZA

Low

Low

Low

High

High

High

0.8

0.8

0.8

Survival probability

Survival probability

Survival probability

0.6

0.6

0.6

0.4

0,4

0.4

0.2

Progress Free Interval HR -0.49 (0.50-0.94)

0.2

0.5

1.0

1.5

2.0

Progress Free Interval HR -2.04(1.34-3.12)

0.2

Progress Free Intervall HR- 158(1.48-2.11)

0.0

P= 0.02

0.0

P=0.001

0.0

- 0.002

0

50

100

0

40

80

120

160

0

30

60

90

120

Time (months)

Time (months)

Time (months)

CharacteristicsN (%)HR (95% CI)P value
ACC771.836 (1.231-2.740)0.003
BLCA3990.940 (0.866-1.020)0.139
BRCA10820.86 (0.56-1.32)0.492
CESC3020.906 (0.744-1.104)0.326
CHOL350.854 (0.490-1.489)0.577
COAD4611.447 (1.200-1.746)<0.001
DLBC480.504 (0.168-1.509)0.221
ESAD791.054 (0.834-1.410)0.546
ESCC820.835 (0.643-1.085)0.178
GBM1550.954 (0.873-1.042)0.205
HNSC4760.914 (0.837-0.998)0.045
KICH642.510 (1.343-4.691)0.004
KIRC5281.984 (1.587-2.480)20.001
KIRP2841.330 (0.822-2.151)0.245
LGG5190.865 (0.714-1.047)0.137
LIHC3651.221 (1.048-1.421)0.01
LUAD4911.085 (0.967-1.218)0.166
LUSC4441.011 (0.901-1.136)0.85
OV3520.948 (0.883-1.018)0.142
PAAD1720.959 (0.838-1.096)0.537
PRAD4973.065 (0.917-10.238)0.069
READ1601.474 (0.926-2.347)0.102
SARC2570.999 (0.888-1.123)0.981
SKCM4500.956 (0.906-1.073)0.739
STAD3491.019 (0.894-1.162)0.774
TGCT1391.929 (0.197-18.910)0.573
THYM1181.345 (0.433-4.175)0.608
UCEC5491.408 (1.229-1.612)<0.001
UCS540.977 (0.740-1.291)0.871
CharacteristicsN (%)HR (95% CI)P value
ACC791.469 (1.122-1.924)0.005
BLCA4140.947 (0.885-1.013)00.115
BRCA10821.021 (0.900-1.158)0.75
CESC3060.879 (0.746-1.036)0.125
CHOL360.822 (0.520-1.301)0.403
COAD4771.248 (1.072-1.452)0.004
DLDC480.050 (0.500-1.449)0.507
ESAD800.949 (0.758-1.189)0.651
ESCC820.884 (0.736-1.062)0.188
GBM1680.937 (0.862-1.018)0.125
HNSC5010.939 (0.875-1.007)0.079
KICH641.909 (1.099-3.317)0.022
KIRC5371.790 (1.464-2.189)40.001
KIRP2071.390 (0.987-1.958)0.06
LGG5271.057 (0.914-1.223)0.457
LIHC3731.246 (1.102-1.409)<0.001
LUAD5261.045 (0.959-1.139)0.315
LUSC4970.983 (0.899-1.075)0.711
OV3771.002 (0.941-1.067)0.949
PAAD1781.051 (0.921-1.200)0.461
PRAD4991.552 (1.090-2.208)0.015
READ1660.999 (0.704-1.417)0.994
SARC2631.001 (0.917-1.093)0.985
SKCM4571.033 (0.966-1.103)0.323
STAD3720.977 (0.872-1.094)0.685
THCA5101.411 (1.054-1,889)0.021
TGCT1390.973 (0.463-2.045)0.943
THYM1181.828 (1.147-2.913)0.011
UCEC5511.260 (1.146-1.385)<0.001
UCS560.998 (0.765-1.302)0.989

Figure 4. Prognostic value of CDKN2A expression in pan-cancer. The Cox regression and Kaplan-Meier analysis of CDKN2A expression in OS (A), DSS (B), and PFI (C). 0 < HR (95% CI) < 1 means that CDKN2A may play a protective role in cancer, and HR (95% CI) > 1 indicates CDKN2A may play an adverse role in pan-cancer. CDKN2A = cyclin dependent kinase inhibitor 2A, DSS = disease specific survival, OS = overall survival, PFI = progress free interval.

time was similar between high and low CDKN2A (see Figure S2B, Supplemental Digital Content 2, http://links.lww.com/ MD/1755, Supplemental Content, which indicated the effect of CDKN2A on disease outcomes). Forest plot indicated that high level of CDKN2A portended shorten progress-free inter- val in ACC (P = . 005, Fig. 4C), COAD (P = . 004, Fig. 4C), KICH (P = . 022, Fig. 4C), KIRC (P < . 001, Fig. 4C), LIHC (P < . 001, Fig. 4C), PRAD (P = . 015, Fig. 4C), THYM (P =. 011, Fig. 4C) and UCEC (P <. 001, Fig. 4C). However, the Kaplan- Meier curve found that KICH and THYM are not statistically significant (see Figure S2C, Supplemental Digital Content 2, http://links.lww.com/MD/I755 Supplemental Content, which indicated the effect of CDKN2A on disease outcomes).

3.4. CDKN2A genetic alteration analysis

CDKN2A genetic alteration in pan-cancer was explored to elu- cidate the possible mechanisms that affected the expression. Figure 5A indicated that the highest alteration frequency of CDKN2A (>50%) happened in GBM patients, of which “Deep Deletion” was the primary alteration type. HNSC patients had the highest “mutation” frequency (almost 20%). As presented in Figure 5B, 382 mutations were found in the CDKN2A sequence, of which truncating seems to be the main mutation type. Moreover, most of the mutation was located in the “Ank_2” (Ankyrin repeats, 52-133) domain. The R80*/Q alteration with the highest alteration frequency was detected in 45 cases of car- cinoma, and its mutation site was presented in the 3D structure

Figure 5. Mutation feature of CDKN2A in pan-cancer performed by cBioPortal tool. The mutation status (A) and mutation types of CDKN2A (B) were displayed. The mutation site with the highest change frequency (R80*Q) was visualized in the 3D structure of CDKN2A protein (C). The correlation between CDKN2A alteration and patient prognosis, including OS, DFS, DSS and PFI, was represented (D). CDKN2A = cyclin dependent kinase inhibitor 2A, DFS = disease-free survival, DSS = disease specific survival, OS = overall survival, PFI = progress free interval.

A

C

Mutation

Structural Variant

Amplification

Deep Deletion

Multiple Alterations

50%

Aberation Frequency

-

30%

20%


Suchesi variant dele

ÇNA dela

Griblastone M/Mforme (ICDA, PinCancer Atas)

Persons Adenocarcinoma (TCGA, PanCancer Altas)

Esophageal Adenocarcinoma (TCSA PreCancer Atas)

Mesithetoma (YOGA, PanCarcer Aties)

Long Squamous Ces Cantinone (FCIGA, PanCareer Allas)

pran biren &-Cet Lymphoma (TCCA, ParCances ADEU

seocartin (TCGA ParCancer Adas)

Slumsach Adenocarcinoma (TOGA, PaCenses Adas;

Conom ICDA ParCancer Attas: Bingen Lower Gradte Otome (TCOA, PeConce Adas)

Laver Hepatocelular Carcinome (TCCA, PanCanone Asas)

Ovarien Sieruns Cystasenocarunema (TCGA, ParCancer Afas)

Paymonus (ICCA PuCancer Allasi

Katves Hanal Papmary Col Carcinoma (TOGA, ParCancer ABas)

na (ICGA PinCancer Anas

Wages Penal Des Caf Carcinoma (TOGA, PanCancer Afas) Chpestupendos Cel Cantinone (TOGA, PanCareer Adas)

Uterne Corpus Endomenar Carcinoma (TCGA, ParCancer Alan)

Vadoes Croixghete (TCDA, Ag:)

Pagoio Carcinoma (TOGA Pa-Cances Alas) happenedbypar Cat Tamers (TCGA, ParCancu Atus)

tegeven and Paragangiona (TCGA, ParCancer Adas)

Ovest Metanouna (TCCA, PanCancer ABas)

B

119

Missense

R80*/Q (n=45)

# CDKN2A Mutations

45

207

Truncating

7

Inframe

35

Splice

14

SV/Fusion

0

Ank

Ank_2

D

0

100

156aa

OS

DFS

10

DFS

DFS

-im


-



-

-

-

-

ACC

COAD

LIHC

PRAD

GEGEGGGREE

OS

DFS

-

OS

PFI




-

GBM

GBM

SKCM

SKCM

OS

DFS


DSS

PFI


KIRC

KIRC

KIRC

KIRC

of CDKN2A protein (Fig. 5C). The survival analysis showed that the CDKN2A alteration resulted in a poor prognosis in ACC, COAD, LIHC, PRAD, GBM, SKCM, and KIRC patients (Fig. 5D).

3.5. DNA methylation analysis

Numerous types of research have indicated that DNA methyl- ation, as an epigenetic modification, contributed to regulating the expression of cancer-related genes.[31] Thus, the promoter methylation level of CDKN2A between tumors and normal tissues was explored via the “CPTAC” dataset. As displayed in Figure 6A, compared with normal samples, the promoter methyl- ation level of CDKN2A was dramatically increased in most can- cers (e.g., BLCA, COAD, KIRC, LIHC, and so on), except KIRP with decreased methylation level. No obvious change in meth- ylation was found in TGCT, THCA, stomach adenocarcinoma,

and THYM. Then, the “MethSurv” web tool was performed to further excavate the effect of CDKN2A methylation on sur- vival. Figure 6B indicated that higher CDKN2A methylation (both island and N_shore region) led to poor prognosis in ACC patients. For KIRC, DNA methylation in the N_shore region induced decreased survival probability. There is no significant survival difference between the lower versus higher CDKN2A methylation group in COAD, SKCM, UCEC, and LIHC.

3.6. The correlation analysis between CDKN2A expression and immune infiltration

As we all know, the tumor microenvironment affects tumor occurrence and development, in which the infiltration of immune cells, especially macrophages and CAF, plays crucial roles. So, here we explored the relationship between CDKN2A expres- sion and immune infiltration in TCGA tumors by the “Immune”

A

Proonatet methylation level of CERCHIZA in BLCA

Promoter methylation level of CDKN2A is COAD

Promoter methylation level of CD822A in FORC

Promoter methylation level of CDANZA in BRCA

Promoter methylation level of CDKNZA is CHOL

Median: 0.072

Median: 0,085

Median: 0.059

Median: 0.063

Median: 0.063

Median: 0.061

Median: 0.054

Median: 0.053

Median: 0.062

Median: 0.053

p = 3.29E-07

p = 1.62E-12

p = 2.16E-10

p = 1.63E-12

p = 4.38E-05

TOGA samples

=

TOCA samples

TOCA sangles

TEBA sungkes

TOCA tangles

Promoter methylation level of CDKONZA.in CHOL

Promoter methylation level nif CDKNÍŽA in ESCA

Promoter methylation level of CDKN2A in Ckat

Promoter methylation level of CORNZA in HNSC

Promitar methylation level of CDON02 A in kiky

Mediarc 0.081

Median: 0.676

Median: 0.076

Median: 0.075

Median: 0.053

Median: 0.000

Median: 0.063

Median: 0.049

Median: 0.063

Median: 0.061

p = 0.008

p = 3.88E-05

p = 0.41

p < 1E-12

p = 0.049

-

TCCA samples

TOCA samples

TOCA comptes

FCGA samples

TOGA sangle

Promoter methylation level of CDKN2A in KiRP

Promoter methylation level of CDKNZA In LUAD

Promoter methylation level of COKN2A in LUSC

Promoter methylation level of CDKNZA in FAAD

Promoter methylation level of CDKENZA in PRAD

Median: 0.064

-

Median: 0.10/

Median: 0,07

Median: 0.067

Median: 0.067

Median: 0.057

Median: 0.053

Median: 0,049

Median: 0.092

Median: 0.068

p = 2.53E-07

p = 1.77E-06

p < 1E-12

p = 2.00E-05

p = 7.67E-05

=

TOCA samples

=

-

TOCA Hempler

TELA samples

TOCA samples

Promoter methylation level of CDR22A in ASAD

Promoter methylation level of CDENZA in SARC

Promoter methylation level of CDANZA is TGCT

Promoter methylation level of CDANZA In STAD

Promoter methylation level of CDKNZA in THCA

Median: 0.075

Median: 0.052

Median: 0.051

Median: 0.879

Median: 0.859

Mediar: 0.058

Median: 0.048

Median: 0.064

Median: 0.046

Median: 0.069

p = 3.72E-08

p = 1.84E-04

p = 0.0503

p = 0.4650

p = 0.2728

=

=

CGA samples

TCCA samples

TOGA sengles

TOCA samples

1CCA samples

Promoter methylation level of CDANZA In THYM

Promoter misthylation level of CDKNZA In UCEC

Median: 0.072

Median: 0.051

Medien: 0.064

Median: 0.051

p = 0.7222

p = 1.22E-11

B

Figure 6. Methylation analysis in tumors. (A) The promoter methylation level of CDKN2A in pan-cancer. (B) Survival analysis of CDKN2A methylation in ACC, COAD, KIRC, SKCM, UCEC and LIHC. ACC = adrenocortical carcinoma, CDKN2A = cyclin dependent kinase inhibitor 2A, COAD = colon adenocarcinoma, KIRC = kidney renal clear cell carcinoma, LIHC = liver hepatocellular carcinoma, SKCM = skin cutaneous melanoma, UCEC = uterine corpus endometrial carcinoma.

Cancer: ACC

Cancer: KIRC

COKINZA + 1450000 Hody-40and-491.3001 799

CEKAIRA - HAR Rin, Body & Shore(go-3004.7)

CDENJA - Body, SIFR-N More-4937810/19

CDKNJA - ISExon Body-island-(01 1001 799

CORNJA - PAPP XDIŞ Hoy-N Shore-(00-1000079

=

=

3

ت

=

-

=

=

=

=

=

:

=

=

=

*

=

=

=

=

=

=

=

=

#

-

#

3

2

2

.

1000

9

1000

-

.

1000

3000

®

1000

2000

-

-

2000

-

-

tunivel time Here!

Cancer: COAD

Cancer: SKCM

CUANTA + 1SFF wie Body-edand-( q1 300: 39

CERNIA - ISTE xong Boden Shore-egosorsa rs

KORNJA - Body: TUINN Shore-2017810/19

CARNICERNUTRAS - Estizone 13.1500-and-egoso/sos CDen//c(DRN/BAS , stixon: 19:500-hland-go/5679

5

=

5

=

=

-

a

=

=

=

2

GW

=

¥

¥

=

1

=

=

=

2

=

%

*

x

3

-

8

®

1000

®

1000

-

-

-

.

-

-

D

4000

22000

.

3000

1000

8000

Cancer: UCEC

Cancer: LIHC

=

=

=

-

=

3

=

3

2

=

4

1000

-

1

1000

2000

500

1000

-

2000

Survival time liduyağ

module of TIMER web serve. Heatmap data and Scatter plot data indicated a significantly positive association between CDKN2A expression and the infiltration of macrophages (MO and M1) in BLCA, PARD and THCA. For BRCA, we found a positive

relationship between CDKN2A level and the infiltration of M0 and M1 cell but noted a negative association in M2 cell infiltra- tion. Moreover, the CDKN2A expression in CESC, LUAD, and OV was positively correlated with the estimated infiltration of

Figure 7. Correlation analysis between CDKN2A expression and immune infiltration in pan-cancer. (A) A positive correlation between immune infiltration of macrophages and CDKNA2 expression in BLCA, CESC, BRCA, COAD, LUAD, OV, PRAD and THCA. (B) CDKN2A expression was positively correlated with the infiltration of cancer-associated fibroblasts in BLCA-Luma, COAD, KIRP, TGCT and THCA, but negatively correlated in CESC. The relationship was displayed in different algorithms. A positive correlation was labeled as red color, while negative correlation was blue. * P < . 05, ** P < . 01. BLCA = bladder urothelial carci- noma, BRCA = breast invasive carcinoma, CESC = cervical squamous cell carcinoma and endocervical adenocarcinoma, CDKN2A = cyclin dependent kinase inhibitor 2A, CESC = cervical squamous cell carcinoma and endocervical adenocarcinoma, COAD = colon adenocarcinoma, LUAD = lung adenocarcinoma, OV = ovarian serous cystadenocarcinoma, PRAD = prostate adenocarcinoma, THCA = thyroid carcinoma.

A

S . CDKN2A Expression Level (log2 TPM) CDKN2A Expression Level (log2 TPM) CDKN2A Expression Level (log2 TPM) CDKN2A Expression Level (log2 TPM) COKN2A Expression Level (log2 TPM) 1

CDKN2A Expression Level (log2 TPM) CDKN2A Expression Level [log2 TPM) CDKN2A Expression Level (log2 TPM) CDKN2A Expression Level (log2 TPM; COKN2A Expression Level (Jog2 TPM) 4

CDKN2A Expression Level (log2 TPM) CDKN2A Expression Level (log2 TPM) CDKN2A Expression Level (log2 TPM)

Portty

Macrophage MO CIBERSORT-ABS

Purty

Macrophage MI QUANTISEO

Purity

Macrophage MI_QUANTISEO

10.0-

98-1

10.0

ACC

E

BLCA

7.5

10

7.5

BRCA

..

.. ..

5.0

BLCA

BLCA

5.0

CESC

BRCA-Basal

A

BRCA-Her2

2.5

2.5

BRCA-LumA

.. ..

0.0

0

0.0

.

BRCA-LumB

.

.

0.25

0.50

0.75

1.000.0

0.1

0.2

0.3

0.25

8.50

0.75

1.000.0

01

82

0.25

0.50

0.75

1.000.00

0.05

0.10 0.

0.20

Purity

Infiltration Level

Purity

Infiltration Level

Purity

Infiltration Level

CESC

… .

CHOL

.

Purity

Macrophage MD_CIRERSORT ABS

Purity

Macrophago MI_XCELL

Purity

Macrophage M2_TIDE

COAD

·

*

5

.

DLBC

.

1.5

5

1.5

ESCA

.

S.

BACA

O

BACA

BACA

GBM

.

HNSC

.. ..

. ..

* p <0.05

2.5

.5

2.5-

HNSC-HPV-

-

** p<0.01

HNSC HPV+

**

Correlation

0.0

1.0

0.50

0,75

1.00 0.0

0.2

04

0.0

0.25

0.25

0.50

0.75

1.000/00

0,05

0.10

0.15

0.25

0.50

0.75

1.000.15 -0.10 -0.05 0.00 0.05 0.10

KICH

.. ..

Purity

Infiltration Level

Purity

Infiltration Level

Purity

Infiltration Level

KIRC

0.5

KIRP

*

0.0

Purity

Macrophage_XCELL

Purity

Macrophage M1 CIBERSORT

Purity

Macrophage MI_QUANTISEO

·

95884

10.0

LGG

… .. ..

-0.5

.

LIHC

**

++

-1.0

2

“.

2

7,3

LUAD

… ..

..

COAD

0

LEAD

6

LUSC

5.0

OV

… ..

.. ..

*

2.5

PAAD

.

%

PRAD

… .. ..

*

0.25

0.50

0.75

1.000.00

0.05

0.10

0.25

0.50

0.73

1.00 0.0

0.1

0.3

0,4

0.8

1.00.00

0.05

0.10

0.15

0.28

READ

.. ..

..

.

Purity

Infiltration Level

Purity

Infiltration Level

Purity

Infiltration Level

SARC

Purity

Macrophage MO CIRERSORT ABS

Purity

Macrophage MI QUANTISEO

SKCM

S

.

197822

SKCM-Metastasis

SKCM-Primary

V

STAD

. ..

PRAD

PRAD

TGCT

O

THCA

… …

.

-

4

THYM

%

UCEC

..

0.75

.50

0.75

1. 000.00

0.05

0.10

0.15

0.20

0.25

0.50

0.75

1.000.00

0.05

0.10

0.15

0.20

Purity

UCS

Infiltration Level

Purity

Infiltration Level

MO CIBERSORT

MO CIBERSORT.ABD

MI CHERSORT

MI CIBERSORT-ABS

M1 QUIANTISEQ

141 XCELL

M2 CIBERSORT

M2 CIBERSORTABS

42 QUANTISEQ

112 TIDE

M2 XCELL

EPIC

TIMER

XCELL

Purity

Macrophage MO_CIBERSORT-ABS

Purity

Macrophage MI QUANTISEQ

.

A

E

.

-

NRO - 04

A

V

THICA

THICA

3

B

0.00

0.25

0.50

0.75

1.00 0.0

0.1

0.2

Infiltration Level

0.00

0.25

0.50

0.75

1.000.00

0.04

0.08

Purity

Purity

Infiltration Level

0.12

ACC

CDKN2A Expression Level (log2 TPM)

BLCA

Purity

cer associated fibroblast_MCPCOUNT

CDKN2A Expression Level (log2 TPM)

Purity

cer associated fibroblast MCPCOUNT

BRCA

1*

BRCA-Basal

=

BRCA-Her2

6

BACA-LumA

COAD

V

BRCA-LumA

**

BRCA-LumB

2

CES

·

1

CHOL

0.25

0.25

1.00

0

10000 20000 30000 40000

0.25

250

Infiltration Level

0.75

1.00 0

10000

20000

10000

400€

Purity

Purity

Infiltration Level

COAD

..

DLBC

.

COKN2A Expression Level (log2 TPM)

Purity

cer associated fibroblast_MCPCOUNT

CDKN2A Expression Level (log2 TPM;

Purity

Cancer associated fibroblast XCELL

ESCA

9

GBM

A

HNSC

* p < 0.05

S

HNSC-HPV-

FORP

TGCT

** p ≤ 0.01

HNSC-HPV+

**

Correlation

KICH

.

1.0

·

KIRC

0.5

0.25

0.50

0.75

1.00 0

2500

5000

7500

0.25

0.50

0.75

1.00 0.0

0.4

0.2

0.3

0.4

KIRP

**

00

Purity

Infiltration Level

Purity

Infiltration Level

LGG

.

0.5

CDKN2A Expression Level (log2 TPM)

COKN2A Expression Level (log2 TPM)

LIHC

+1,0

Purity

Cancer associated Bbroblast XCELL

10,0

Purity

cer associated fibroblast MCPCOUN

10.0

LUAD

0 - 3.07640

.

LUSC

7.5

7.5

OV

5.0

THCA

5.0

CESA

PAAD

PRAD

25

2.3

READ

0.0

SARC

0.00

0.25

29000

0.0

-

0.50

0.75

1.00 0

10000

0.25

0.50

0.75

1.000.0

0.1

0.2

0.3

Purity

Infiltration Level

Purity

Infiltration Level

SKCM .

SKCM-Metastasis

.

SKCM-Primary

STAD

TGCT

THCA

..

..

..

THYM

UCEC

UCS

EPIC

MCP-COUNTER

NOE

XCELL

M1 macrophages based on all algorithms (Fig. 7A). Besides, the expression of CDKN2A in BRCA-lumA, COAD, KIRP, TGCT, and THCA was positively associated with the CAF infiltration, while CESC was negatively correlated (Fig. 7B).

3.7. Enrichment and co-expression analysis of CDKN2A

To elucidate the function of CDKN2A, GEPIA2, and xiantao bioinformatic toolbox were carried out. At the gene expression level, GEPIA2 was used to find similar genes. As represented in Figure 8B, the CDKN2A expression was positively correlated with identical genes, including ASF, CDC20, MCM2, replica- tion factor C subunit 4, RNSSEH2A and Mago homolog, exon junction complex subunit. The correlation analysis suggested that genes-ASF, CDC20, MCM2, replication factor C subunit 4, RNSSEH2A and Mago homolog, exon junction complex subunit- were positively related to most cancer, especially ACC, BLCA, HNSC-HPV+, SARC, and LIHC (Fig. 8C). However, the above genes seemed to play a weakly negative role in TGCT (Fig. 8C, blue square). Moreover, Protein-Protein Network Interaction (Fig. 8A) was established to display identified CDKN2A-binding molecules intuitively. The top 20 molecules (core molecules) were chosen for further GO and KEGG enrich- ment analysis. Go enrichment analysis results indicated that CDKN2A and the core molecules mainly involved biological process, such as G1/S transition of mitotic cell cycle, cell cycle G1/S phase transition, DNA replication initiation, and DNA- dependent DNA replication (Fig. 8D, blue columns). For CC analysis, core molecules were mostly involved in the chromo- somal region, chromosome, telomeric region, MCM complex and nuclear chromosome, and telomeric region (Fig. 8D, red col- umns). The molecular function showed that the core molecules were mainly involved in DNA helicase activity, single-stranded DNA binding, 3’-5’ DNA helicase activity and DNA replica- tion origin binding (Fig. 8D, green columns). KEGG analysis figured out that core molecules mainly participated in the p53 signaling pathway, non-small cell lung cancer, Cellular senes- cence, Endocrine resistance, Chronic myeloid leukemia, Glioma, Melanoma, Bladder cancer, DNA replication and Cell cycle signaling pathways (Fig. 8E). Moreover, single-gene GSEA was performed to analyze CDKN2A-relevant pathways in ACC, COAD, KIRC, LIHC, PRAD, SKCM, THCA, and UCEC. The top 5 most frequently enriched pathways were visualized (see Figure S3A-H, Supplemental Digital Content 3, http://links. lww.com/MD/I756, Supplemental Content, which suggested CDKN2A-relevant pathways in pan-cancer).

As we all know, the cell cycle, immune response and metabo- lism affect the occurrence and development of pan-cancer. The relevant pathways related to cell cycle, immune regulation (e.g., signaling by interleukins, integrin cell surface interactions, inte- grin-1 pathway and so on) and metabolisms relevant to oxida- tive stress, mitochondrial activity and fatty acid were conducted. GSEA results showed that CDKN2A was positively enriched in the cell cycle in ACC and PRAD (Fig. 9A and C). Furthermore, CDKN2A was found to be positively associated with the path- ways related to oxidative response, fatty acid metabolism and mitochondrial metabolism in ACC (Fig. 9A), COAD (Fig. 9B), PRAD (Fig. 9C), and SKCM (Fig. 9D). Moreover, CDKN2A was positively related to immune-related pathways in ACC (Fig. 9A) and PRAD (Fig. 9E). Conversely, the aforementioned pathways in SKCM and THCA were negatively regulated. For KIRC, LIHC and UCEC, the pathways mentioned above were not dramatically enriched (see Figure S4A-C, Supplemental Digital Content 4, http://links.lww.com/MD/I757, Supplemental Content, which indicated CDKN2A-relavant pathways related to cell cycle, immune and metabolisms in KIRC, LIHC, and UCEC). All of the above results indicated that the CDKN2A expression was linked to some critical pathways in cancer for- mation, occurrence and metastases.

To further validate the roles of CDKN2A in different cancers, the co-expression analysis related to cuproptosis, immune check- point and immune regulation was also conducted. As presented in Figure 10A, cuproptosis-related genes in ACC were positively correlated with CDKN2A expression while negatively related in KIRC, PRAD, and THCA. Moreover, the correlation analysis of immune checkpoints showed that most genes were significantly positively associated with CDKN2A in BLCA, BRCA, HNSC, KICH, KIRP, LIHC, TGCT, and THCA. Conversely, some immune checkpoint genes in UCEC were negatively associated with CDKN2A (Fig. 10B). In addition, the correlation analy- sis of immune-regulatory genes results was simultaneous with the previous ones (Fig. 10C and D). Consequently, CDKN2A might play a pivotal role in pan-cancer copper metabolism and immune infiltration.

4. Discussion

CDKN2A, a tumor suppressor and cell cycle regulator, was verified to take part in the cell cycle and p53 signaling path- way.[13] CDKN2A encoded 2 proteins, named p16INK4a and p14ARF.[32] It is reported that p14ARF regulated the cell cycle by preventing p53 inactivation, while p16INK4a prevented the phosphorylation of Rb proteins. [32,33] Previous studies have revealed the suppressive roles of CDKN2A in some cancer types.[20,34-36] Disruption of CDKN2A (deletion or methylation) has been reported to be a frequent event in tumorigenesis, which affected the clinical characteristics and patient outcomes.[14-16] Alhejaily and his colleagues revealed that silence of CDKN2A by deletion or methylation was correlated with worse clinical outcome in follicular lymphoma.[14] A meta-analysis from Xing showed that CDKN2A hypermethylation was significantly associated with unfavorable prognosis in CRC patients.[15] Similar results were also discovered in PDAC, thymic carci- noma, HNSC and MIBC.[16-19] Although the tumorigenic effects of disruption of CDKN2A were well confirmed, unexpectedly high CDKN2A indicated a poor clinical outcome in some can- cer, including COAD, BLCA and LIHC.[17,20-22] The mechanism by which CDKN2A serves as a tumor suppressor but results in unfavorable prognosis is speculated that CDKN2A may involve in tumor initiation and progression as an anti-cupropto- sis gene by performing genome-wide CRISPR/Cas9 knock-out screens.[8,23-25] However, as an anti-cuproptosis gene, the roles or signatures and the regulatory mechanisms of CDKN2A in pan-cancer have not yet been explored in depth. Thus, we con- ducted this pan-cancer analysis for CDKN2A.

In this study, overexpressed CDKN2A was observed in the majority of cancer tissues (e.g., ACC, BLCA, CESC, lymphoid neoplasm diffuse large B-cell lymphoma, esophageal carcinoma, UCEC and so on), while downregulated CDKN2A was found in TGCT tissues by the assessment of CDKN2A mRNA level. These results indicated that CDKN2A might involve in different pathways in cancer initiation and progression. Consistent with the transcriptional level, an augmented translational level of CDKN2A was found in KIRC, UCEC, LUAD, and LIHC sam- ples. Curiously, the protein expression of CDKN2A in HNSC was not consistent, which might be due to metabolism or post- transcriptional protein modification. Moreover, it is verified that the expression of CDKN2A was related to the tumor patholog- ical stages in ACC, COAD, KICH, UCEC, KIRC, KIRP, LIHC, and THCA, which suggested the potential of CDKN2A as a bio- marker for the clinical stage.

The Cox regression and Kaplan-Meier analysis revealed that upregulated CDKN2A predicted a poor prognosis for ACC, COAD, KIRC, LIHC, PRAD, SKCM, THCA, and UCEC. Concordant with this, recent convincing research also

A

B

onca

MCMS

p-value = 0

p-value = 0 R =0,42

.

p-value = 0

P

R = 0.47

*

R=0,42

log2(ASF18 TPM)

-

log2(CDC20 TPM)

log2(M/CM2 TPM)

.

1

CO

1

1

CDC?

1

.

*

MENTACE

.

·

.

A

A

·

#

.

.

.

.

#

4

.

·

10

·

=

.

.

.

1

-

-

log2(CDKN2A TPM)

log2(CDKN2A TPM)

log2(CDKN2A TPM)

PSMCA

-

CDKNZA

PSMICH

e

p-value = 0 R = 0.41

#

p-value = 0 R=0.4

p-value = @ R = 0.39

POMICH

.

.

log?(RFC4 TPM)

log2(RNASEH2A TPM)

-

-

log2(MAGOH TPM)

e

.

.

1

.

A

2

CERTRAPS

-

9

*

WECNI

-

.

-

O

·

-

4

0

2

4

.

.

1

6

2

.

«

4

4

·

2

4

1

NO

log?(CDKN2A TPM)

log2(CDKN2A TPM)

log2(CDKN2A TPM)

C

ASF1B

..

**

.

**

*

..

**

..

**

..

* p < 0.05

CDC20

**

**

**

.

**

**

*

**

**

**

**

**

**

**

**

**

**

**

**

**

**

*

** p < 0.01

Correlation

MAGOH

**

**

**

**

**

**

**

**

**

.

**

**

**

**

**

**

.

.

.

**

**

1.0

MCM2 ..

0.5

**

**

**

**

*

**

**

**

..

..

**

0.0

RFC4

..

..

·

.

..

*

..

..

*

..

·

.

-0.5

RNASEH2A

.

*

**

..

·

·

-1.0

ACC (n=79)

BLCA (n=408)

BRCA (n=1100)

BRCA-Basal (n=191)

BRCA-Her2 (n=82)

BRCA-LumA (n=568)

BRCA-LumB (n=219)

CESC (n=306)

CHOL (n=36)

COAD (n=458)

DLBC (n=48)

ESCA (n=185)

HNSC (n=522) GBM (n=153)

HNSC-HPV- (n=422)

HNSC-HPV+ (n=98)

KICH (n=66)

KIRC (n=533)

KIRP (0=290)

LIHC (n=371)

LUAD (n=515)

LUSC (n=501)

OV (n=303)

PAAD (n=179)

PRAD (n=498) READ (n=166)

SARC (n=260) SKCM (n=471)

SKCM-Metastasis (n=368)

SKCM-Primary (n=103)

STAD (n=415)

TGCT (n=150)

THCA (h)=509)

THYM (n=120)

UCEC (n=545)

UCS (n=57)

D

DNA helicase activity

single-stranded DNA binding

3’-5’ DNA helicase activity

DNA replication origin binding

chromosomal region

BP

chromosome, telomeric region

Cc

MF

MCM complex

nuclear chromosome, telomeric region

DNA-dependent DNA replication

DNA replication initiation

cell cycle G1/S phase transition

G1/S transition of mitotic cell cycle

E

0

5

10

15

20

25

-Log 10 (p.adjust)

CDC45

TP53

p53 signaling pathway

RB1

Non-small cell lung cancer

-log10(Pvalue)

ORC5

Cellular senescence

20

ORC4

ORC2

Endocrine resistance

10

MDM2

Chronic myeloid leukemia

MCM7

Glioma

MCM6

MCM5

Melanoma

MCM4

MCM2

Bladder cancer

EP300

CDKN2A

DNA replication

Count

CDK4

Cell cycle

16

.

4

CDC6

0.25

0.50

0.75

Gene.Ratio

OntologyIDDescriptionGeneRatiopvaluep.adjustqvalue
BPGO:0000082G1/S transition of mitotic cell cycle17/206.20e-297.75e-263.64e-26
BPGO:0044843cell cycle G1/S phase transition17/201.96e-281.22e-255.74e-26
BPGO:0006270DNA replication initiation11/205.92e-262.46e-231.16e-23
BPGO:0006261DNA-dependent DNA replication11/201.23e-183.83e-161.80e-16
CCGO:0000784nuclear chromosome telomeric region8/202.46€-131.890-111.190-11
CCGO:0042555MCM complex5/204.93e-131.90e-111.19e-11
CCGO:0000781chromosome, telomeric region8/201.92e-124.94e-113.10e-11
CCGO:0098687chromosomal region8/209.31e-101.79e-081.13e-08
MFGO:0003688DNA replication origin binding11/203.13e-283.10€-261.52e-26
MFGO:00431383'-5' DNA helicase activity5/201.65e-118.14e-103.98e-10
MFGO:0003697single-stranded DNA binding7/202.60e-118.56e-104.19e-10
MFGO:0003678DNA helicase activity6/202.80e-106.94e-093.39e-09
OntologyIDDescriptionGeneRatiopvaluep.adjustqvalue
KEGGhsa04110Cell cycle16/193.29e-272.53e-251.35e-25
KEGGhsa03030DNA replication5/191.47e-085.64e-073.01e-07
KEGGhsa05219Bladder cancer5/192.89e-087.42e-073.96e-07
KEGGhsa05218Melanoma5/195.16e-078.700-064.64e-06
KEGGhsa05214Glioma5/196.34e-078.70e-064.64e-06
KEGGhsa05220Chronic myeloid leukemia5/196.78e-078.70e-064.64e-06
KEGGhsa01522Endocrine resistance5/192.41e-062.65e-051.42e-05
KEGGhsa05223Non-small cell lung cancer4/192.03e-051.49e-047.96e-05
KEGGhsa04115p53 signaling pathway4/192.15e-051.49e-047.96e-05
KEGGhsa04218Cellular senescence5/192.36e-051.49e-047.96e-05

Figure 8. Co-expression and enrichment analysis of CDKN2A in pan-cancer. (A) Experimentally identified CDKN2A binding molecules were exhibited in PPI networks established by STRING. (B) Core CDKN2A-related genes, including ASF, CDC20, MCM2, RFC4, RNSSEH2A and MAGOH, were analyzed by GEPIA2. (C) The correlation between CDKN2A expression and selected CDKN2A-related genes (ASF, CDC20, MCM2, RFC4, RNSSEH2A and MAGOH) in pan-cancer was represented via heatmap. GO (D) and KEGG (E) enrichment for the top 20 experimental identified CDKN2A binding molecules from PPI network. BP = biological process, CC = cellular component, CDKN2A = cyclin dependent kinase inhibitor 2A, GEPIA2 = gene expression profiling interactive analysis, GO = gene ontology, KEGG = Kyoto encyclopedia of genes and genomes, MF = molecular function.

A

B

0.5

0.25

0.6

Enrichment Score

0,4

Enrichment Score

0.00

ACC

Enrichment Score

COAD

Enrichment Score

0.3

0,4

0.2

02

0.25

0.4

0.6

NEIACTOME CELL CYCLE

0.50

0.0

REACTOME SIGNALINGE_BY_INTERLEUKEN’S

W

-

REACTOME OXIDATIVE STRESS INDUCED SENTE

SẮP CELL CYCLE

WP MITOCHONDRIAL COMPLEX | ASSEMBLY MODEL COPHIC

0.0

KEACTOMESINITURIN CELL SURFACE INTERACTIONS

HE

NT

-0.5

REACTOME APOPTOSIS INDUCED DNA FRAGMENTATION

2

I

Ranked list metric

Ranked list metrie

Ranked list metrie

Ranked list metric

SO

5.0

5.4

¥

15.

25

2.5

0.0

0.0

0.0

2.3

2.5

&

6

1000

2000

3000

4000

5000

1000

2000

1000

4000

5000

1000

2000

3000

4000

$000

$000

10000

Rank in Ordered Dataset

Rank in Ordered Dataset

Rank in Ordered Dataset

Rank in Ordered Dataset

C

D

E

0.6

WWWW

0.0

0,4

0.6

A

02

0.0

0.4

PRAD

Enrichment Score

Enrichment Score

Enrichment Score

Enrichment Score

0.2

SKCM

0.4

0,4

THCA

1,2

NEACTOME SIGNALING BY INTERLELKES

REACTOME CELL SURFACE INTERACTIONS AT THE VINCULAR

REACTOME ROLE OF PHOSPHOLIPIDS IN PHAGOCYTOSIS

REACTOME MITOCHONDRIAL FATTY ACID BETA OXIDATION KEGG OXIDATIVE PHOSPHORYLATION

REACTOME NEUTROPHIL DEGRANULATION ANTOINE RECEPTOR INTERM TIEN

0.0

WE, COMPLEMEN

AND COAGULATION CASCADES

4.6

I’VE REGULATION OF NOTCHA SIGNING

REACTUNE SIGNALING BY THE BELLL TO

0.0

2

REACTOME CELL_SUREALE INTERACTIONS AT THE VASSLITR W.

-KEOG DRDO METABOLISM OTHEX ENZYMES

- REACTOME ANTIGEN ACTIVATES B CELE RECTPTHE IC

REACTOME CELL CYCLE CHECKPOINTS

REACTOME INTERFERON SIGNALING

II

1

.

II

Ranked list metric

4

4

Ranked list metric

4

Ranked list metric

4

Ranked list metric

M

1

7

·

2

2

=

V

2500

5000

7500

1000

2000

1000

4000

1000

2000

3000

4000

4000

8000

2000

16000

Rank in Ordered Dataset

Rank in Ordered Dataset

Rank in Ordered Dataset

Rank in Ordered Dataset

0 1
REACTOME CHLA CICLI 0 3781.8340.048
KEGG, CHIL CYCLE 0.4571.905
WP_CILL CYCLE00000028
NESFOR
WP GRIDATIVE PHOS_06702.1220041
WP OXIDATION WY C. 0-6512.2286.6466041
REACTOME_FATTY_AC .. 4-445-1.31400120.048
REACTOME THE CITIL_ 4524-225700520044
WP_MITOCHONDRIAL, - 6-1701.500
ID RSNESpaint
REACTOME INTIGRIN, 05591.9900.0460:038
PID INTEGAINT_PAT. 0.5850.0050018
BLACTOME SIGNALIN, 0.33501760.147
NESpatjustFOR
REACTOME_DKCOATN .- 6.60%-4.585004400M
REACTOME ACTIVATE_ 06951.77000140016
REACTOME, APOPTOSE. 0.829-1.71506490.040
0 ESMISDaGustFOR
WP_COMPLIMINT_AND_0.59320100:0440:040
REACTOME NEGATIVE. 8538184800440040
KIGQ_DRUG_METABOL_ 061720770.0440:040
REACTOME CELL CYCLE 0 3571.29000440.040
NESpadustFOR
REACTOME CELL SUR 0.55121300 0140.025
REACTOME IMMUNORE: - 0.558-217100140:026
REACTOME_SIGNALIN -0.6912.5250 034
BLACTOME ANTIGEN _ 0.72625680.014
0NESDAGItIDE
REACTOME ROLE_OF _- - 4725-2.5090.0540.0.26
KEOG ONDATIVE PHL.052421120.0460.036
REACTOME CELE CYC 04122076POST0010
REACTOME MITOCHON.0.54600820064
NESpaquetFOR
REACTOME SIGNAUN_0.4911.9090.0260022
REACTOME NEUTROPH , 0.5111.9950.0060.022
K10G CYTOKINE CYT.05862.2180:0250022
REACTOME CELL SUIL: 0 7252.634002600/2
REACTOME INTERFER,. 0-48900066022

Figure 9. Gene set enrichment analysis. The roles of CDKN2A in ACC (A), COAD (B), PRAD (C), SKCM (D), THCA (E) by performing Gene Set Enrichment Analysis (GSEA). ACC = adrenocortical carcinoma, CDKN2A = cyclin dependent kinase inhibitor 2A, COAD = colon adenocarcinoma, PRAD = prostate adeno- carcinoma, SKCM = skin cutaneous melanoma, THCA = thyroid carcinoma.

discovered that overexpressed CDKN2A was correlated with the poor prognosis in CRC.[21,34,37] These results revealed the potential of CDKN2A as an original prognostic predictor for some cancer types.

Deneka et al(38] found the relationship between CDKN2A mutation and tumor mutation burden. Liu and his colleagues demonstrated that the presence of CDKN2A deletion might induce the progression of ESCC.[39] In T-cell acute lymphoblastic leukemia, CDKN2A deletion was an independent poor prog- nostic factor.[40] Similar to the above findings, deep deletion hap- pened in most cancer types. Besides, CDKN2A mutation played important roles in certain cancers. Our results showed that the CDKN2A amplification has arisen in ACC, OV, UCEC and TGCT, and the alteration of CDKN2A implicated inferior out- comes in cancer such as ACC, COAD, LIHC, KIRC, and so on. These results were seemly contradictory to the aforementioned CDKN2A expression levels. Possible reasons for these conflict- ing results are as follows: different change types occurred in tumors. For instance, compared with deep deletion, a mutation might have a greater impact on tumorigenesis in certain human tumors, which resulted in a loss of function. Then compensatory overexpression of CDKN2A was measured. Moreover, amplifi- cation might occupy center stage in some cancers, leading to the upregulated expression.

As an epigenetic modification, DNA methylation contrib- utes to regulating the expression of cancer-related genes.[31] A meta-analysis performed by Zhou pointed out that CDKN2A methylation had a crucial role in the occurrence of esopha- geal cancer.[41] However, Cao et al indicated that CDKN2A

methylation was not significantly correlated with the progres- sion of PRAD.[42] This study explored that obviously increased promoter methylation level of CDKN2A happened in most can- cers, which led to poor outcomes in ACC and KIRC. Therefore, we hypothesized that aberrant methylation of CDKN2A might take part in tumor progression and prognosis. Furthermore, enrichment analysis results suggested CDKN2A was closely correlated to cell cycle, immune responses and DNA replica- tion. Especially, CDKN2A was positively enriched in cell cycle, oxidative response, fatty acid metabolism and mitochondrial metabolisms and immune-related pathways in ACC and PRAD. Thus, the results conformed to the existing mechanisms of can- cer formation, occurrence and metastases.[43] Recent studies have revealed the indispensable and integral roles of tumor microen- vironment (TME) in tumor physiology.[44,45] Growing evidence discovered that immune cells, transformed ECM and soluble factors presented in TME gave rise to tumor progression and metastasis.[44,46,47] Macrophages, the most abundant immune cells residing in TME, reflected the Th1/Th2 paradigm via anti- gen presentation and pathogen phagocytosis, which played crucial roles in immune homeostasis.[44] Tumor-associated mac- rophages (TAMs) were found to be correlated with shorter sur- vival in cancer patients.[48,49] The analysis from Luo et al revealed that CDKN2A was positively related to the infiltration of mac- rophages in LIHC,[22] which indicated its value for prognosis or immunotherapy.[50] Xiao and his team discovered that high-risk PDAC group had higher CDKN2A mutations with mounted infiltration of macrophages MO and M2.[51] CAF, as the most essential components of the TME, have also been verified to

Figure 10. Gene correlation analysis. The association between CDKN2A expression and genes related to cuproptosis (A), immune checkpoint (B), immune-sup- pressive status (C) and immune-activation (D) was presented by heatmaps. Each square represented the correlation between CDKN2A and other genes. Red suggested positive correlation, and blue represented negative correlation. * P < . 05, ** P < . 01. CDKN2A = cyclin dependent kinase inhibitor 2A.

A

ACC

.

BLCA

CDKNIA

Log- (1 PM+)

Cancer: ACC

CDKNZA

LAS2 (TPM+1

Cancer: KIRC

BRCA

**

**

*

High

Les

High

CESC

**

CHOL

FDXF

COAD

.

**

**

**

DLD

DLBC

TAI

-

DUD

DLAT

.

ESCA

TIAN

LIAS

*

GBM

.

..

* p < 0.05

LIFT

LIPTI

HNSC

..

** p < 0.01

MIFI

MTFI

KICH

*

POILAI

POHB

POHA1

KIRC

-

Correlation

POHE

KIRP

**

1.0

7-con

4

.

2

Z-score

4

.

LGG

2

LIHC

.

..

0.5

LUAD

**

0.0

LUSC

COKNZA OF: (TPM+

Cancer: PRAD

CDKNZA

Log_ (TPM+1)

Cancer: THCA

OV

0.5

Low

Low

PAAD

High

PRAD

**

-1.0

READ

**

.

FDXI

TOXI

SARC

OLD

DLAT

DILD

SKCM

DE.AT

STAD

**

**

**

LIAS

GLS

LIAS

LIPTE

TGCT

..

**

..

MTFİ

LIPTI

MTFI

THCA

..

..

PORAI

PDHAI

THYM

.

PDIES

PORB

UCEC

UCS

Z-score

5.0 -25 00 2.5

FDX1

DLD

DLAT

LIAS

GLS

UPT1

MTF1

PDHA1

PDHB

B

CDKNZA Leg, (TPM+1)

Cancer: LIHC

CDKNZA

Log, (TPM+1)

Cancer: THCA

ACC ..

BLCA **

-

Low

Low

**

BRCA **

**

**

High

Highs

CESC

-

CHOL

TNFRSPS

TNFRSP9

COAD

CD86

-

CD274

CD86

DLBC

CD274

ESCA

..

TNFSF15

GBM

* p <0.05

TNFSETS

CINO

THESEIR

HNSC

**

..

**

TNERSE25

TNERSIES

KICH

.. **

.

** p < 0.01

KIRC

**

Correlation

-

KIRP

**

.

-

1.0

BTNŽAI

BTNZA1

LGG

-

¥

-

CD200

CD200

LIHC

**

-

**

**

**

0.5

Zoom

LUAD

**

**

**

**

35.00 23 30 75

Z-score

-5.0 -23 00

25.

LUSC

..

0.0

..

OV

-

-0.5

PAAD

PRAD

-1.0

CDKNZA Log- (TPM+

Cancer: KICH

CDKNZA

Log: (1FM-1)

Cancer: KIRP

..

Low

Low

READ

.

**

High

High

SARC

SKCM

**

STAD

..

INFRSPY

TNFRSF+

CD4

TGCT

-

CDYM

THCA

..

..

**

TNFSF15

THYM

TNFSFI8

TNFSF15

CD46

TNFSFI#

UCEC

..

..

..

TNFRSF25 CDX

TNFRSF25

UCS

CDC8

TNFRSF9

CD44

CD86

CD274

TNFSF15

TNFSF18

CO40

TNFRSF25

CD28

ICOS

BTLA

TNFRSF14

BTNZA1

CD200

BILA

ICOS

BILA

TNERSE 14

BTNZAS

THERSF14

CD200

BINIAI

CD200

*

C

Z-score

4

1

Z-score

2

ACC

..

BLCA

BRCA

CESC

**

CHOL

COAD

**

**

DLBC

ESCA

CDKNZA Log, (TPM+)

Cancer: KICH

Cancer: THCA

GBM

*p <0.05

..

CDKNZA

Low

HNSC

..

..

** p < 0.01

High

High

KICH

..

..

**

..

**

KIRC

Correlation

VTCNI

KIRP

1.0

TOFRRI

VTCNI

CD274

TOFER1

LIHC

..

-

0.5

LUAD

**

CD%

CD274

LUSC

*

0.0

CD244

CDS

CD:44

.

RTLA

OV

**

**

**

**

**

BILA

-0.5

CTLA4

PAAD

LAGO

.

CTLA4

PRAD

..

-1.0

HAVCR2

LAG3

KOR

RACK2

READ

.

POCOILGS

KDR

SARC

POCDILGO

SKCM

Z1000

25

5.0

Z-voor

STAD

.

**

2

.

TGCT **

THCA

.

.

THYM

UCEC

**

**

**

UCS

VTCN1

TGFBR1

CD274

CD96

CD244

BTLA

CTLA4

LAG3

HAVCR2

KDR

PDCDILG2

D

ACC

.

*

CDKNZA

Løg, (TPM+1)

Cancer: KICH

Cancer: THCA

INGA

**

CDKNZA

..

Low

Low High

CESC

*

-

.. ..

High

CHOL

CORD

-

.. ..

-

.. .

DLBC

-

ESCA

GBM

-

*

*p < 0.05

=

HNSC

.. ..

-

ENTPOI

KICH

-

KIRC ..

-

* p < 0.01

2

A

O

Correlation

-

KIRP

-

-

.

-

.. ..

-

.. ..

A

KRACI

TNERSP9

45

NERS#25

PAAD

PRAD READ SARC

1.0

TNFRSF4

ENFRSP4

-

~

SKCM STAD

.

A

-

TGCT

.

… .

-

THCA

THYM


-

BINLE

.

NENLE

UCEC

Z-wooN

$

0

10

UCS

TIFSFIS

CO276 ENTPOS

CXCL12

CO27 KIRCH

.

2

0

2

.

ONE FOSAS

TheFRSF

INFSF14

OFRSF4

Creo

ICOSLO

3

PVR

TMIOD2

CXCRA

have a critical role in tumorigenesis and progression.[52] CAFs interact with immune cells by the secretion of growth factors, cytokines and other molecules, and induce an immunosuppres- sive TME that facilitates the growth of tumor cells.[52-54] Similar to the previous studies, the immune infiltration analysis in our

study suggested that CDKN2A expression was positively asso- ciated with the infiltration of macrophages or CAFs in pan-can- cer, which exposed the important roles of CDKN2A in tumor immunology. It is noteworthy that more macrophages M1 infil- tration was found in some CDKN2A overexpressed samples,

which seemly contradictory to the aforementioned prognostic evaluation of CDKN2A. These conflicting results may be due to the double-edged roles of CDKN2A in pan-cancer. Furthermore, our study also analyzes the relationship between CDKN2A expression and immune-related genes, including the immune checkpoint, immunosuppressive and immune activated genes. Fascinatingly, consistent with enrichment analysis results, a strong correlation between CDKN2A and immune-related genes was found in diverse cancers. These exciting results offered new insights and orientations for cancer treatment. Moreover, CDKN2A associated with the majority of cuproptosis-related genes in ACC, KIRC, PRAD and THCA, which implied the vital roles of CDKN2A in copper metabolism.

Nevertheless, there are some limitations in this study. Firstly, this study had not yet explored the definite mechanisms of CDKN2A expression in copper metabolisms. How CDKN2A expression affected immune infiltration and tumor progression needs to be verified in later research. Secondly, we explored the double-edged roles of CDKN2A as tumor suppressors or oncogenes in pan-cancer, and it might be induced by the diverse origin of cancers and tumor heterogeneity. In addition, more Vivo and Vitro experiments are further needed for verification.

In summary, our study pointed out the potential of CDKN2A as a predictor and biomarker associated with prognosis. The results provided new insights and orientations for novel anti-cancer treatments via facilitating tumor silence or regulat- ing cuproptosis.

Acknowledgments

We would like to thank the Tianjin Union Medical Center and Tianjin Institute of Coloproctology for the support. In addi- tion, we thank all tools used in this study for data analysis and visualization.

Author contributions

Conceptualization: Xipeng Zhang.

Data curation: Di Zhang.

Formal analysis: Di Zhang, Xipeng Zhang.

Investigation: Di Zhang, Tao Wang.

Methodology: Yi Zhou.

Project administration: Xipeng Zhang.

Resources: Di Zhang, Yi Zhou.

Software: Tao Wang.

Supervision: Xipeng Zhang.

Validation: Xipeng Zhang.

Visualization: Di Zhang, Tao Wang.

Writing - original draft: Di Zhang.

Writing - review & editing: Xipeng Zhang.

References

[1] Sung H, Ferlay J, Siegel RL, et al. Global Cancer Statistics 2020: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 2021;71:209-49.

[2] Bray F, Laversanne M, Weiderpass E, et al. The ever-increasing impor- tance of cancer as a leading cause of premature death worldwide. Cancer. 2021;127:3029-30.

[3] Vanden Berghe T, Linkermann A, Jouan-Lanhouet S, et al. Regulated necrosis: the expanding network of non-apoptotic cell death pathways. Nat Rev Mol Cell Biol. 2014;15:135-47.

[4] Zhou J, Guo H, Liu L, et al. Pyroptosis patterns of colon cancer could aid to estimate prognosis, microenvironment and immunotherapy: evi- dence from multi-omics analysis. Aging (Milano). 2022;14:7547-67.

[5] Hua L, Lei P, Hu Y. Construction and validation model of necropto- sis-related gene signature associates with immunity for osteosarcoma patients. Sci Rep. 2022;12:15893.

[6] Fujihara KM, Zhang BZ, Jackson TD, et al. Eprenetapopt triggers fer- roptosis, inhibits NFS1 cysteine desulfurase, and synergizes with serine and glycine dietary restriction. Sci Adv. 2022;8:eabm9427.

[7] Qin X, Ma D, Tan YX, et al. The role of necroptosis in cancer: a dou- ble-edged sword? Biochim Biophys Acta Rev Cancer. 2019;1871:259-66.

[8] Tsvetkov P, Coy S, Petrova B, et al. Copper induces cell death by target- ing lipoylated TCA cycle proteins. Science. 2022;375:1254-61.

[9] Keswani T, Mitra S, Bhattacharyya A. Copper-induced immunotoxicity involves cell cycle arrest and cell death in the liver. Environ Toxicol. 2015;30:411-21.

[10] Jian Z, Guo H, Liu H, et al. Oxidative stress, apoptosis and inflamma- tory responses involved in copper-induced pulmonary toxicity in mice. Aging (Milano). 2020;12:16867-86.

[11] Kim BE, Nevitt T, Thiele DJ. Mechanisms for copper acquisition, distri- bution and regulation. Nat Chem Biol. 2008;4:176-85.

[12] Liu H. Pan-cancer profiles of the cuproptosis gene set. Am J Cancer Res. 2022;12:4074-81.

[13] Kreuger IZM, Slieker RC, van Groningen T, et al. Therapeutic strat- egies for targeting CDKN2A loss in melanoma. J Invest Dermatol. 2023;143:18-25.

[14] Alhejaily A, Day AG, Feilotter HE, et al. Inactivation of the CDKN2A tumor-suppressor gene by deletion or methylation is common at diag- nosis in follicular lymphoma and associated with poor clinical out- come. Clin Cancer Res. 2014;20:1676-86.

[15] Xing X, Cai W, Shi H, et al. The prognostic value of CDKN2A hypermethylation in colorectal cancer: a meta-analysis. Br J Cancer. 2013;108:2542-8.

[16] Oshima M, Okano K, Muraki S, et al. Immunohistochemically detected expression of 3 major genes (CDKN2A/p16, TP53, and SMAD4/DPC4) strongly predicts survival in patients with resectable pancreatic cancer. Ann Surg. 2013;258:336-46.

[17] Worst TS, Weis C-A, Stöhr R, et al. CDKN2A as transcriptomic marker for muscle-invasive bladder cancer risk stratification and therapy deci- sion-making. Sci Rep. 2018;8:14383.

[18] Ryu HJ, Kim EK, Heo SJ, et al. Architectural patterns of p16 immu- nohistochemical expression associated with cancer immunity and prognosis of head and neck squamous cell carcinoma. APMIS. 2017;125:974-84.

[19] Aesif SW, Aubry MC, Yi ES, et al. Loss of p16(INK4A) expression and homozygous CDKN2A deletion are associated with worse outcome and younger age in thymic carcinomas. J Thorac Oncol. 2017;12:860-71.

[20] Li CH, Haider S, Boutros PC. Age influences on the molecular presen- tation of tumours. Nat Commun. 2022;13:208.

[21] Kang N, Xie X, Zhou X, et al. Identification and validation of EMT- immune-related prognostic biomarkers CDKN2A, CMTM8 and ILK in colon cancer. BMC Gastroenterol. 2022;22:190.

[22] Luo JP, Wang J, Huang JH. CDKN2A is a prognostic biomarker and correlated with immune infiltrates in hepatocellular carcinoma. Biosci Rep. 2021;41:BSR20211103.

[23] Zhou Z, Zhou Y, Liu D, et al. Prognostic and immune correlation eval- uation of a novel cuproptosis-related genes signature in hepatocellular carcinoma. Front Pharmacol. 2022;13:1074123.

[24] Bian Z, Fan R, Xie L. A novel cuproptosis-related prognostic gene sig- nature and validation of differential expression in clear cell renal cell carcinoma. Genes. 2022;13:851.

[25] Chen Y. Identification and validation of cuproptosis-related prognostic signature and associated regulatory axis in uterine corpus endometrial carcinoma. Front Genet. 2022;13:912037.

[26] Li T, Fan J, Wang B, et al. TIMER: a web server for comprehensive anal- ysis of tumor-infiltrating immune cells. Cancer Res. 2017;77:e108-10.

[27] Tang Z, Kang B, Li C, et al. GEPIA2: an enhanced web server for large- scale expression profiling and interactive analysis. Nucleic Acids Res. 2019;47:W556-60.

[28] Chandrashekar DS, Bashel B, Balasubramanya SAH, et al. UALCAN: a portal for facilitating tumor subgroup gene expression and survival analyses. Neoplasia. 2017;19:649-58.

[29] Gao J, Aksoy BA, Dogrusoz U, et al. Integrative analysis of complex cancer genomics and clinical profiles using the cBioPortal. Sci Signal. 2013;6:pl1.

[30] Modhukur V, Iljasenko T, Metsalu T, et al. MethSurv: a web tool to perform multivariable survival analysis using DNA methylation data. Epigenomics. 2018;10:277-88.

[31] Liu D, Li L, Wang L, et al. Recognition of DNA methylation molecu- lar features for diagnosis and prognosis in gastric cancer. Front Genet. 2021;12:758926.

[32] Adib E, Nassar AH, Akl EW, et al. CDKN2A alterations and response to immunotherapy in solid tumors. Clin Cancer Res. 2021;27:4025-35.

[33] Chan SH, Chiang J, Ngeow J. CDKN2A germline alterations and the relevance of genotype-phenotype associations in cancer predisposition. Hered Cancer Clin Pract. 2021;19:21.

[34] Wang QQ, Zhou Y-C, Zhou Ge Y-J, et al. Comprehensive proteomic signature and identification of CDKN2A as a promising prognostic biomarker and therapeutic target of colorectal cancer. World J Clin Cases. 2022;10:7686-97.

[35] Cheng T, Wu Y, Liu Z, et al. CDKN2A-mediated molecular subtypes characterize the hallmarks of tumor microenvironment and guide precision medicine in triple-negative breast cancer. Front Immunol. 2022;13:970950.

[36] Lee CC, Kuo Y-C, Hu J-M, et al. MTNR1B polymorphisms with CDKN2A and MGMT methylation status are associated with poor prognosis of colorectal cancer in Taiwan. World J Gastroenterol. 2021;27:5737-52.

[37] Bruneval F, Dattani N, van Setten MJ. The GW miracle in many-body perturbation theory for the ionization potential of molecules. Front Chem. 2021;9:749779.

[38] Deneka AY, Baca Y, Serebriiskii IG, et al. Association of TP53 and CDKN2A mutation profile with tumor mutation burden in head and neck cancer. Clin Cancer Res. 2022;28:1925-37.

[39] Liu M, Liu Y, Zhou R, et al. Absence of NOTCH1 mutation and pres- ence of CDKN2A deletion predict progression of esophageal lesions. J Pathol. 2022;258:38-48.

[40] Wang HP, Zhou Y-L, Huang X, et al. CDKN2A deletions are associated with poor outcomes in 101 adults with T-cell acute lymphoblastic leu- kemia. Am J Hematol. 2021;96:312-9.

[41] Zhou C, Li J, Li Q. CDKN2A methylation in esophageal cancer: a meta-analysis. Oncotarget. 2017;8:50071-83.

[42] Cao Z, Wei L, Zhu W, et al. Meta-analysis of CDKN2A methylation to find its role in prostate cancer development and progression, and also to find the effect of CDKN2A expression on disease-free survival (PRISMA). Medicine (Baltimore). 2018;97:e0182.

[43] Pang B, Xu X, Lu Y, et al. Prediction of new targets and mechanisms for quercetin in the treatment of pancreatic cancer, colon cancer, and rectal cancer. Food Funct. 2019;10:5339-49.

[44] Hinshaw DC, Shevde LA. The tumor microenvironment innately mod- ulates cancer progression. Cancer Res. 2019;79:4557-66.

[45] Nakamura K, Smyth MJ. Myeloid immunosuppression and immune checkpoints in the tumor microenvironment. Cell Mol Immunol. 2020;17:1-12.

[46] Petitprez F, Meylan M, de Reynies A, et al. The tumor microenviron- ment in the response to immune checkpoint blockade therapies. Front Immunol. 2020;11:784.

[47] Vitale I, Manic G, Coussens LM, et al. Macrophages and metabolism in the tumor microenvironment. Cell Metab. 2019;30:36-50.

[48] DeNardo DG, Ruffell B. Macrophages as regulators of tumour immu- nity and immunotherapy. Nat Rev Immunol. 2019;19:369-82.

[49] Cassetta L, Pollard JW. Targeting macrophages: therapeutic approaches in cancer. Nat Rev Drug Discov. 2018;17:887-904.

[50] Liu H, Jia S, Guo K, et al. INK4 cyclin-dependent kinase inhibitors as potential prognostic biomarkers and therapeutic targets in hepatocellu- lar carcinoma. Biosci Rep. 2022;42:BSR20221082.

[51] Xiao Z, Li J, Yu Q, et al. An inflammatory response related gene sig- nature associated with survival outcome and gemcitabine response in patients with pancreatic ductal adenocarcinoma. Front Pharmacol. 2021;12:778294.

[52] Barrett R, Pure E. Cancer-associated fibroblasts: key determinants of tumor immunity and immunotherapy. Curr Opin Immunol. 2020;64:80-7.

[53] Barrett RL, Pure E. Cancer-associated fibroblasts and their influence on tumor immunity and immunotherapy. eLife. 2020;9:e57243.

[54] An Y, Liu F, Chen Y, et al. Crosstalk between cancer-associated fibro- blasts and immune cells in cancer. J Cell Mol Med. 2020;24:13-24.