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Research article

The prognostic value and immunological role of SULF2 in adrenocortical carcinoma

Jiusong Yan ª,1, Xiaodu Xie ª,1, Qinke Lib, Peihe Lianga, Junyong Zhang a,"", Guangyong Xu ª,

a Department of Urology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China

b Department of Gynecology and Obstetrics, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China

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ARTICLE INFO

Keywords:

Adrenocortical carcinoma (ACC) Sulfatase2 (SULF2) Prognosis Tumor immune regulation

ABSTRACT

Background: Adrenocortical carcinoma (ACC) represents the rare urological epithelial cancer of urinary tract, which has a large mass and is usually diagnosed at the advanced stage, thus inducing the poor prognosis. As a result, early detection and diagnosis are more important for the prognosis rather than the treatment of ACC. There is evidence supporting the association of Sulfatase2 (SULF2) with bladder cancer. However, the relationships of SULF2 with the clinical features and immune infiltration of ACC remain unclear.

Methods: This work comprehensively investigated the different expression levels of SULF2 within ACC and its prognostic significance through various databases including Gene Expression Profiling Interaction Analysis (GEPIA), Tumor Immune Estimation Resource (TIMER), The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), Kaplan-Meier (KM) plotter and UAL- CAN. Besides, SULF2 levels within different tumor and paraneoplastic tissues were examined based on Human Protein Atlas (HPA) and TIMER. Afterwards, this study identified differentially expressed genes (DEGs) in high-compared with low-SULF2-expression groups. To predict the possible interaction between SULF2 and its targets, a protein-protein interaction (PPI) network was constructed based on relevant data collected in STRING database. Besides, the SULF2 func- tional annotation was carried out, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and GSEA. In addition, gene mutation analysis was also performed based on the cBioPortal database. The relation of SULF2 with immune infiltration was analyzed from various aspects by using the resources of various databases including TIMER, TISIDB, and GEPIA, which was first reported in this work. Finally, R package was utilized to plot the receiver oper- ating characteristic (ROC) curves of diagnosis, time-dependent survival, and the association of SULF2 with cancer stage and the nomogram model. Finally, CellMiner dataset was adopted for SULF2 correlation as well as drug sensitivity analysis.

Results: Relative to healthy people, SULF2 level markedly elevated within ACC tissues. Besides, SULF2 up-regulation significantly predicted the dismal prognostic outcome, which may be an important prognostic factor. Afterwards, the PPI network was constructed, and the possible link of SULF2 with the corresponding targets was predicted. Besides, up-regulated SULF2 expression was tightly related to immune regulation and tumor-infiltration immune cell (TIICs), including

* Corresponding author.

** Corresponding author.

E-mail addresses: zhangmachine@cqmu.edu.cn (J. Zhang), 300453@hospital.cqmu.edu.cn (G. Xu).

1 These authors contributed equally.

https://doi.org/10.1016/j.heliyon.2023.e13613

Received 19 October 2022; Received in revised form 1 February 2023; Accepted 6 February 2023

CD8+, CD4+ and mast cells. Finally, SULF2 expression was speculated to help determine the sensitivity of certain drugs.

Conclusions: SULF2 may offer a new therapeutic target for ACC patients and become an important potential prognostic biomarker.

1. Introduction

Adrenocortical carcinoma (ACC) represents a rare while insidious endocrine disease, and its annual incidence is about 2 per million. Available data show that ACC cases have a low (<50%) 5-year survival rate [1]. However, there are few available treatment options, and radical surgical resection is the only cure method. Even so, unfortunately, most patients who have undergone radical surgery still develop local recurrence and metastasis [2]. With regard to the prognostic factors of ACC, in addition to tumor stage, the reference value of gene sequencing and other molecular biological examinations is limited although they have been available [3,4].

As a member of the sulfatase family, Sulfatase2 (SULF2) affects heparan sulfate proteoglycan (HSPG) sulfate pattern, thus contributing to cancer progression [5]. In tumor cells, the abnormal expression of SULF2 can induce structural changes in pro- teoglycans, leading to abnormal tumor cell proliferation, enhanced invasion capacity and increased susceptibility to lymph node metastasis (LNM). The role of SULF2 in numerous tumor types, including bladder cancer and pancreatic cancer, has been studied investigated [6,7]. As of yet, no study has explored the relationship between SULF2 and ACC.

In the present research, SULF2 expression together with the relation with ACC patient survival was analyzed by electronic data- bases including Gene Expression Profiling Interaction Analysis (GEPIA), The Cancer Genome Atlas (TCGA), UALCAN datasets, as well as Kaplan-Meier (KM) plotter. Besides, relation between SULF2 and tumor-infiltrating immune cell (TIICs) under different tumor microenvironments (TME) was also evaluated based on TISIDB and Tumor Immune Estimation Resource (TIMER) databases.

2. Methods

2.1. Differential expression of SULF2 in ACC

Genotype-Tissue Expression (GTEx) database and TCGA were used as the source of research data for the web-based database GEPIA (http://gepia.cancer-pku.cn/index.html) [8]. The “DIY Expression” option in GEPIA was selected for investigating SULF2 levels among ACC cases and normal tissues. Then, SULF2 expression in ACC and normal tissues was compared using GSE14922 and GSE12368 from Gene Expression Omnibus (GEO) database (http://www.ncbi.nlm.nih.gov/geo/) [9]. To be specific, the former included 4 pairs of tumor and normal tissue samples, and the latter contained 12 tumor and 6 normal tissue samples. Moreover, SULF2 levels among distinct samples collected in Human Protein Atlas (HPA) (http://www.proteinatlas.org/) and Tumor Immune Estimation Resource (TIMER2.0) (http://cistrome.shinyapps.io/timer/) were compared [10,11]. Besides, differentially expressed genes (DEGs) were identified by R package in high-compared with low-SULF2-expression groups upon the thresholds of p < 0.05 and |log2 fold change (FC)|≥1.5. Finally, R packages “ggplot2” was utilized to illustrate the results in the form of volcano plots.

2.2. UALCAN

UALCAN is a powerful network interaction platform, which allows researchers to gather valuable information and perform multiple bioinformatics analyses [12]. In this study, UALCAN was adopted to compared the expression of SULF2 in ACC according to patient’s gender, individual cancer stages (stage 1, 2, 3, 4), lymph node metastasis (LNM), and TP53 mutation status.

2.3. Functional annotation analysis of protein-protein interaction (PPI) networks

STRING (http://string-db.org) is the powerful platform developed to constructed protein networks, which allows researchers to input a list of proteins by name or amino acid sequence. STRING was utilized in the present work to construct a PPI network of SULF2. Our default minimum required interaction score is 0.4. Besides, GeneMANIA (https://genemania.org) helps researchers integrate biological network to sequence genes and predict gene functions [13]. In this study, GeneMANIA was employed to construct gene interaction networks of SULF2 and predict the related functions. In addition, the relevance of nine genes associated with SULF2 was analyzed in STRING database using R package. Gene Oncology (GO) together with KEGG analysis was subsequently conducted on the nine genes associated with SULF2 and DEGs by using ggplot2 R packages. Additionally, gseKEGG and gsePathway functions in clusterProfiler were also applied in gene set enrichment analysis (GSEA).

2.4. Genetic mutation analysis

SULF2 mutation features were analyzed based on the cBioPortal for Cancer Genomics database (http://cbioportal.org) via genome- wide pan-cancer analysis (ICGC/TCGA, Nature 2020) from pan-cancer studies [14,15].

Fig. 1. Sulfatase2 (SULF2) expression levels in different human cancers. (A) Different expression level of SULF2 in normal human tissues from The

membranous

Staining: Low

Patient id: 1966

Normal tissue

Adrenal gland

Female, age 71

B

Endometrium

50

100

150

200

A

score

E

C

Location:Cytoplasmic/

Quantity: < 25%

Intensity: Moderate

0

nTPM

0

1

2

3

4

SULF2 Expression Level (log2 TPM)

a

9

Smooth muscle

Ovary

ACC. Tumor (n=79)

Cervix

BLCA. Tumor (n=408)

BLCA.Normal (n=19)

Normal

Esophagus

BRCA.Tumor (n=1093)


(n=4)

Fallopian tube

BRCA.Normal (n=112)

BRCA-Basal. Tumor (n=190)

GSE14922

Gallbladder

T

BRCA-Her2. Tumor (n=82)

BRCA-LumA. Tumor (n=564)

*

Adipose tissue

BRCA-LumB.Tumor (n=217)

Vagina

CESC. Tumor (n=304)

**

CESC.Normal (n=3)

CHOL. Tumor (n=36)

E

Medulla oblongata

Kidney

CHOL.Normal (n=9)

-

COAD. Tumor (n=457)


Pons

Tumor

COAD.Normal (n=41)

(n=4)

DLBC. Tumor (n=48)


Hippocampal formation

Midbrain

T

ESCA.Tumor (n=184)

ESCA.Normal (n=11) GBM. Tumor (n=153)

**

Colon

GBM.Normal (n=5)

HNSC.Tumor (n=520)


HNSC.Normal (n=44)

Rectum

HNSC-HPV+. Tumor (n=97)


HNSC-HPV -. Tumor (n=421)

Breast

KICH. Tumor (n=66)

**

F

KICH.Normal (n=25)


membranous

Location:Cytoplasmic/

Quantity: < 25%

Intensity: Moderate

Staining: Low

Patient id: 2374

Normal tissue

Adrenal gland

Female, age 44

Thyroid gland

Hypothalamus

Appendix

KIRC. Tumor (n=533)

-

score

KIRC.Normal (n=72)

KIRP.Tumor (n=290)


2000

4000

6000

8000

10000

Pituitary gland

KIRP.Normal (n=32)

LAML. Tumor (n=173)

Urinary bladder

LGG.Tumor (n=516)

Heart muscle

Liver

0

LIHC. Tumor (n=371)

LIHC.Normal (n=50)

LUAD. Tumor (n=515)

.

Salivary gland

LUAD.Normal (n=59)

LUSC. Tumor (n=501)


Normal

LUSC.Normal (n=51)

(n=6)

MESO. Tumor (n=87)

T

OV.Tumor (n=303)

GSE12368

Cerebral cortex

Basal ganglia ?

Skin

PAAD. Tumor (n=178)

PAAD.Normal (n=4)

Thalamus

PCPG.Tumor (n=179)

.

**

PCPG.Normal (n=3)

Duodenum

PRAD. Tumor (n=497)


Lymph node

PRAD.Normal (n=52)

(n=12)

Small intestine

READ.Tumor (n=166)

Tumor

READ.Normal (n=10)

SARC. Tumor (n=259)

Placenta

T

SKCM.Tumor (n=103)

SKCM.Metastasis (n=368)

Amygdala

STAD.Tumor (n=415)


STAD.Normal (n=35)

White matter

Prostate

Tonsil

TGCT.Tumor (n=150)

THCA. Tumor (n=501)

THCA.Normal (n=59)

THYM. Tumor (n=120)

Male, age 35

UCEC.Tumor (n=545)

Tongue

The expression of PDCD1 Log2 (TPM+1)

membranous

Location:Cytoplasmic/

Quantity: < 25%

Intensity: Moderate

Staining: Low

Patient id: 2212

Normal tissue

Adrenal gland

Seminal vesicle

G

UCEC.Normal (n=35)

UCS. Tumor (n=57) UVM. Tumor (n=80)

Spinal cord

Testis

0

1

N

3

The expression of SULF2

Choroid plexus

Cerebellum

Stomach

2

0

2

.

.

00

D

Thymus

Log2 (TPM+1)

Lung

4

(num(T)=77; num(N)=128)

Skeletal muscle

Spleen

ACC

Adrenal gland Retina

Bone marrow

6

Parathyroid gland

Epididymis

Pancreas

-0.039

Spearman

9731

8

Human Protein Atlas (HPA) database. (B) Immunohistochemical (IHC) staining of normal adrenal tissue SULF2 in a 71-year-old female from HPA

Analysis (GEPIA). (E, F) SULF2 expression was higher in ACC than in the normal tissue in GSE14922 and GSE12368 ( ** p < 0.01). (G) The cor- 0.01, *** p < 0.001). (D) Increased SULF2 in Adrenocortical carcinoma (ACC) compared with normal tissues in Gene Expression Profiling Interaction database. (C) high expression SULF2 in different tumor types from Tumor Immune Estimation Resource (TIMER2.0) database (*p < 0.05, ** p <

relation analysis between SULF2 and PD1 mRNA level.

2.5. SULF2 and immune infiltration

TIMER2.0 database allows for comprehensively analyzing TIICs levels in different cancer types. By applying the Gene module, users can select one or more genes and see how its or their expression is correlated with TIICs levels. In this work, relation of SULF2 level with gene markers for tumor-infiltrating lymphocytes (TILs), including B cells, CD8+ T cells, Mast cell, M2 macrophages, Tregs and natural killer (NK) cells, was analyzed. TISIDB (http://cis.hku.hk/TISIDB/index.php) has been developed as the integrated web-based database to analyze tumor-immune system interconnectedness, which encompasses an extensive immune data resources [16]. It may help researchers develop new immunotherapeutic targets and forecast immunotherapeutic responses. In our study, TISIDB was chosen to explore the relations of SULF2 with immune-related molecules and cells in ACC.

2.6. Prognostic significance of SULF2 for ACC

The study analyzed whether SULF2 was associated with survival events based on a Cox proportional hazards model that estimated hazard ratios (HRs). Univariate survival analysis was first of all conducted, which obtained HRs, associated 95% confidence intervals (CIs) and p-values upon log-rank test. When the p-value was below 0.05, it indicated statistical significance of our results, which might thus be used for reference. In addition, the present work selected Kaplan-Meier plotter (http://kmplot.com/analysis/) for investi- gating whether SULF2 was of prognostic significance for ACC, like overall survival (OS) as well as disease-free survival (DFS). By using R packages (such as survival packages, pROC, and timeROC), this study also plotted ROC curve and time-dependent curve of diagnosis, and carried out nomogram model analysis. Source data for the above analyses were obtained from TCGA database.

2.7. Drug sensitivity analysis

Data regarding gene expression profiles together with drug sensitivity were collected in the CellMiner dataset. Later, correlation coefficients of SULF2 level with drug sensitivity were determined, and correlation tests were performed using R language. P < 0.05 stood for the significant correlation of the outcomes. A correlation coefficient > 0 indicated the positive gene-drug sensitivity cor- relation, and vice versa.

A

Expression of SULF2 in ACC based on individual cancer stages

250

S1 vs S2 p=0.3034

S1 vs S3 p= 4.182400E-02

200

S1 vs S4 p= 2.023600E-03

Transcript per million

S2 vs S3 p= 0.3129

S2 vs S4 p= 2.435800E-03

S3 vs S4 p= 4.496300E-02

150

100

50

0

Stage1 (n=9)

Stage2 (n=37)

Stage3 (n=16)

Stage4 (n=15)

TCGA samples

B Expression of SULF2 in ACC based on nodal metastasis status

200

NO vs N1 p= 4.488400E-02

150

Transcript per million

100

50

0

NO (n=68)

N1 (n=9)

TCGA samples

C Expression of SULF2 in ACC based on patient’s gender

D Expression of SULF2 in ACC based on TP53 mutation status

Fig. 2. Correlation between SULF2 expression level and clinicopathological parameters of Adrenocortical carcinoma through the UALCAN data- base. (A) Cancer stages (stage 1, 2, 3, 4). (B) Lymph node stage (N 0, 1). (C) Patient's gender (male and female). (D) TP53 mutation status (TP53- Mutant and TP53-NonMutant). S1, stage 1; S2, stage 2; S3, stage 3; S4, stage 4; ACC, adrenocortical carcinoma.

300

Male vs Female p=7.801200E-01

300

TP53-Mutant vs TP53-NonMutant p= 7.944200E-03

250

250

Transcript per million

200

Transcript per million

200

150

150

100

100

50

50

0

Male (n=31)

Female (n=48)

0

TP53-Mutant (n=16)

TP53-NonMutant (n=64)

TCGA samples

TCGA samples

3. Results

3.1. High expression of SULF2 in ACC

According to analysis based on HPA database, SULF2 expression was notably lower in adrenal gland than in other tissues. Meanwhile, immunohistochemical (IHC) results of normal adrenal gland from a 71-year-old female in the database also showed the low expression levels of SULF2 (Fig. 1A and B). Thereafter, it was found that SULF2 expression was up-regulated in ACC, kidney renal clear cell carcinoma (KIRCC) and breast cancer (Fig. 1C). Besides, high SULF2 expression was observed in ACC from TCGA database by GEPIA (p<0.05 , Fig. 1D). By analyzing GSE14922 and GSE12368 from GEO database, the same conclusion was made (Fig. 1E and F). On the other hand, the relationship between SULF2 and PD1 expression was also analyzed, unfortunately, the result was not statis- tically significant (Fig. 1G).

3.2. Relationship between SULF2 expression and cancer stage

By applying UALCAN, SULF2 expression was examined in ACC based on patient’s gender, individual cancer stages (stage 1, 2, 3, 4), LNM, and TP53 mutation status. The data showed that SULF2 showed high expression in intermediate-to-advanced cancers, with significant differences (Fig. 2A). Moreover, SULF2 was expressed at similarly increased levels in ACC patients developing LNM relative to those without LNM (Fig. 2B). However, SULF2 expression levels were similar between male and female ACC patients, which was of

Fig. 3. Differentially expressed genes. (A) Volcanic plot of differentially expressed genes in the high-SULF2 expression group and the low-SULF2 expression group. (B) Gene Oncology and KEGG pathway. (C) Gene set enrichment analysis: KEGG_NEUROACTIVE_LIGAND_RECEPTOR_INTER- ACTION. (D) Gene set enrichment analysis: REACTOME_G_ALPHA_I_SIGALLING_EVENTS.

A

B

antimicrobial humoral response

20

G protein-coupled receptor signaling pathway, coupled

to cyclic nucleotide second messenger

BP

humoral immune response

-Log 10 (P.adj)

15

9

ion channel complex

synaptic membrane

CC

BP

5

collagen-containing extracellular matrix

CC

10

MF

8

channel activity

KEGG

passive transmembrane transporter activity

MF

5

receptor ligand activity

B

Retinol metabolism

0

Drug metabolism - cytochrome P450

KEGG

-8

-4

0

4

8

Neuroactive ligand-receptor interaction

Log2 (Fold Change)

0 5 101520 -Log 10 (p.adjust)

C

D

KEGG_NEUROACTIVE_LIGAND_RECEPTOR_INTERACTION

REACTOME_G_ALPHA ___ SIGNALLING_EVENTS

0.2

0.2

Enrichment Score

Enrichment Score

0.0

0.0

-0.2

NES =- 1.503

-0.2

NES =- 1.421

p.adj = 0.023

p.adj = 0.023

FDR = 0.018

FDR = 0.018

Ranked list metric

5.0

Ranked list metric

5.0

2.5

2.5

0.0

0.0

-2.5

-2.5

-5.0

-5.0

-7.5

-7.5

10000

20000

30000

10000

20000

30000

Rank in Ordered Dataset

Rank in Ordered Dataset

no statistical difference (Fig. 2C). In addition, SULF2 was expressed at higher levels in patients with TP53 mutations in the tumor than in non-mutated patients (Fig. 2D).

3.3. PPI network and functional annotation

DEGs were identified in high-compared with low-SULF2 expression groups using the R package. There were altogether 1889 DEGs obtained, which included 953 with up-regulation and 936 with down-regulation (Fig. 3A). According to Fig. 3B, such DEGs were enriched in antimicrobial humoral response and humoral immune response in the biological process (BP). Meanwhile, the enriched cellular components (CC) terms included synaptic membrane, collagen-containing extracellular matrix and ion channel complex. Furthermore, the enriched molecular function (MF) terms were channel activity, passive transmembrane transporter activity and receptor ligand activity. According to KEGG enrichment, these DEGs were enriched into retinol metabolism, drug metabolism- cytochrome P450 and neuroactive ligand-receptor interaction. As revealed by GSEA results, low-SULF2-expression patients showed significant enrichment of KEGG neuroactive ligand receptor interaction and reactome g alpha I signaling events (Fig. 3C and D). However, there was no enriched pathway in the high-SULF2-expression group.

STRING database assists in building the PPI network related to SULF2, as a result, ten functional partner genes with high con- nectivity were obtained from the network. In fact, HS2ST1 and ENSP00000359579 are two names of Heparan sulfate 2-O-sulfotrans- ferase 1, therefore, 9 functional partner genes were finally obtained (Fig. 4A). Besides, GeneMANIA database-based gene-gene network

Fig. 4. Enrichment analysis of SULF2 in adrenocortical carcinoma. (A) SULF2-interaction proteins in ACC from STRING database. (B) The gene- gene network of SULF2 performed by GeneMANIA database. (C, D) The relevance between SULF2 and functional partner genes. (E) Gene Oncology. (F) KEGG pathway. (G) Gene set enrichment analysis (GSEA). ACC, adrenocortical carcinoma.

A

GLCE

B

ARSA

GPC2

GPC6

GPC3

Networks

XS3ST3A0

GPC5

HS6ST2

Physical Interactions

HS3ST2

AC093155.3

GPC4

Shared protein domains

HS2ST1

GPC1

SULF2

ENSP00000359579

Co-expression

HS6ST

1

HS3ST1

CHST8

GPC3

GLCE

Genetic Interactions

NDST

ARSG

MS3ST380

CHST10

NOSTI

HS6ST2

Functions

SULF2

aminoglycan biosynthetic process

H93ST5

HS2ST1

HS6ST1

HS6ST3

glycosaminoglycan metabolic process

GPC1

aminoglycan metabolic process

COPE

HS3STO

COPE

ARSG

CHST14

sulfotransferase activity

UST

CHST13

transferase activity, transferring sulfur-containing groups

CHST12

proteoglycan metabolic process

CHST11

CHST9

proteoglycan biosynthetic process

C

SULF2

GPC1

GPC3

HS6ST1

HS2ST1

HS6ST2

NDST1

GLCE

COPE

ARSG

D

SULF2

GPC1

GPC3

HS6ST1

HS2ST1

HS6ST2

NDST1

GLCE

COPE

ARSG

SULF2

1

0.21

0.32

0.28

0.25

0.2

0.39

0.2

0.46

-0.02

SULF2

**

**

*

*

**

**

GPC1

0.21

1

0.28

0.52

0.52

0.14

0.15

0.4

0.29

0.19

GPC1

*

**

**

**

**

* p < 0.05

GPC3

0.32

0.28

1

0.42

0.34

0.23

0.24

0.4

0.31

0.19

Correlation

GPC3

**

*

**

**

**

*

*

**

**

** p < 0.01

HS6ST1

0.28

0.52

0.42

1

0.46

0.21

0.23

0.6

0.27

0.21

1.0

HS6ST1

*

**

**

**

**

*

**

*

Correlation

0.5

HS2ST1

0.25

0.52

0.34

0.46

1

0.15

0.5

0.58

0.38

0.32

HS2ST1

1.0

*

**

**

**

**

**

**

**

0.0

0.5

HS6ST2

0.2

0.14

0.23

0.21

0.15

1

0.3

0.03

0.32

0.41

HS6ST2

*

**

**

**

**

-0.5

0.0

NDST1

0.39

0.15

0.24

0.23

0.5

0.3

1

0.32

0.44

0.36

-1.0

NDST1

**

*

*

**

**

**

**

**

**

-0.5

GLCE

0.2

0.4

0.4

0.6

0.58

0.03

0.32

1

0.37

0.28

GLCE

**

**

**

* *

**

**

*

-1.0

COPE

0.46

0.29

0.31

0.27

0.38

0.32

0.44

0.37

1

0.04

COPE

**

**

**

*

**

**

**

**

**

ARSG

-0.02

0.19

0.19

0.21

0.32

0.41

0.36

0.28

0.04

1

ARSG

**

**

**

*

E

F

G

Gene Ontology

aminoglycan biosynthetic process

KEGG pathway

GSEA analysis

glycosaminoglycan biosynthetic process

proteoglycan metabolic process

5

KEGG NEUROACTIVE LIGAND RECEPTOR INTERACTION

heparan sulfate proteoglycan metabolic process

Proteoglycans in cancer

anchored component of membrane

REACTOME G ALPHA I SIGNALLING EVENTS

Padjust

Golgi lumen

CC

lysosomal bamen

8

KEGG

MP

REACTOME CLASS A 1 RHODOPSIN LIKE RECEPTORS

0.023

anchored component of plasma membrane

Glycosaminoglycan biosynthesis - heparan sulfate / heparin

arylsulfatase activity

transferase activity, transferring sulfur-containing

REACTOME GPCR LIGAND BINDING

groups

sulfotransferase activity

¥

heparan sulfate sulfotransferase activity

0

2

4

6

8

10

WP NUCLEAR RECEPTORS METAPATHWAY

0

5

10

15

-Log 10 (p.adjust)

-6

-4

-Log 10 (p.adjust)

-2

0

analysis revealed interaction of SULF2 with 30 candidate target genes (Fig. 4B). Excitingly, SULF2 was strongly linked with nine functional partner genes, which displayed significantly positive correlation with each other (Fig. 4C and D). As shown in Fig. 4E, the GO analysis results revealed the involvement of SULF2 and its partner in BPs including “glycosaminoglycan biosynthetic process”, “aminoglycan biosynthetic process”, “heparan sulfate proteoglycan metabolic process”, and “proteoglycan metabolic process”. The CC terms enriched included “anchored component of membrane”, “Golgi lumen”, “lysosomal lumen” and “anchored component of plasma membrane”. The enriched MF terms were “arylsulfatase activity”, “heparan sulfate sulfotransferase activity”, “sulfotransferase ac- tivity” and “transferase activity, transferring sulfur-containing groups”. Moreover, as demonstrated by KEGG enrichment, these genes were enriched into proteoglycans in cancer and glycosaminoglycan biosynthesis-heparan sulfate/heparin (Fig. 4F). Our GSEA was conducted by using TCGA-derived RNAseq data and the results showed obvious enrichment of KEGG neuroactive ligand receptor interaction and reactome g alpha I signaling events pathways (Fig. 4G).

3.4. Genetic alteration analysis of SULF2 in ACC

The present work attempted to explore the mutational signature of SULF2 in ACC based on the cBioPortal tool, as a results, the genetic alteration frequency of SULF2 was lower than 6% in ACC (Fig. 5A). Fig. 5B displays the mutation spots of SULF2 in ACC. As shown in Fig. 5C-E, there was no significant difference in OS (p = 0.905), progression-free survival (PFS) (p = 0.624) or disease- specific survival (DSS) (p = 0.766) in SULF2-altered ACC group compared with SULF2-unaltered group. In conclusion, SULF2 gene alterations may not be associated with the development of ACC.

3.5. Immune correlation analysis

Immune infiltration is involved in the occurrence and development of tumors. According to our results, SULF2 was associated with the infiltration levels of TILs based on TISIDB database (Fig. 6A). Besides, as shown in Fig. 6B, SULF2 up-regulation led to the decreased TIL infiltration levels, such as Mast cell (rho = - 0.367) and NK cell (rho = - 0.289). However, SULF2 up-regulation showed positive relation to infiltration levels of CD4+ Th1 cell (rho = 0.451) and B cell (rho = 0.24). The statistical results showed that all P-values were less than 0.05. Therefore, it was reasonable to believe that SULF2 showed close relation with tumor immunity, which might affect ACC

Fig. 5. Mutation feature of SULF2 in ACC from TCGA cohort based on the cBioPortal database. (A) The alteration frequency with mutation type of SULF2 in ACC samples from TCGA cohorts. (B) Mutation sites of SULF2 in ACC from TCGA cohort. (C) K-M survival analysis of OS with or without SULF2 alteration. (D) K-M survival analysis of disease-specific survival with or without SULF2 alteration. (E) K-M survival analysis of progress-free survival with or without SULF2 alteration. ACC, adrenocortical carcinoma. OS, overall survival.

A

6%-

B

Alteration Frequency

# SULF2 Mutations

5-

5%-

KB53T

4%-

0-

Sulfatase

DUF3740

0

200

400

600

800

870aa

3%-

C

2%-

100%

Logrank Test P-Value: 0.905

90%

1%-

80%

Probability of Overall Survival

70%

Structural variant data +

60%

Mutation data +

50%

CNA data +

40%

Adrenocortical Carcinoma

30%

20%

10%

0%

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

Overall Survival (Months)

D

E

Overall

Altered group

Unaltered group

Mutation

Amplification

100%

Logrank Test P-Value: 0.766

100%

Logrank Test P-Value: 0.624

90%-

90%

80%-

80%

70%

70%

Disease-specific

60%-

Progression Free

60%

50%

50%

40%

40%

30%

30%

20%

20%

10%-

10%

0%

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

0%

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

Months of disease-specific survival

Progress Free Survival (Months)

Disease-specific

Progression Free

Altered group

Altered group

Unaltered group

Unaltered group

Fig. 6. Correlation of SULF2 expression with immune infiltration in ACC. (A) Correlation between the expression of SULF2 and the abundance of TILs in ACC through TISIDB database. (B) Correlation of SULF2 expression with infiltration levels of TILs in ACC available at TIMER2.0 database. ACC, adrenocortical carcinoma. TILs, tumor-infiltrating lymphocytes.

A

Act CD8

B

SULF2 Expression Level (log2 TPM)

Purity

T cell CD8+_EPIC

T cell CD4+_EPIC

T cell CD4+ (non-regulatory)_XCELL

Rho = - 0.298

Tcm CD8

8

Rho = 0.282

p = 1.498-02

Rho =- 0.231

p = 4.94e-02

p = 1.03e-02

Rho = 0.266

p = 2.29e-02

Tem CD8

6

Act CD4

ACC

Tcm CD4

4.

Tem CD4

Tfh

0.2

0.4

0.6

0.8

1.0 0.00

0.01

0.02

0.03

0.04

0.00

0.05

0.10

0.15

0.20

0.000

0.005

0.010

Purity

Infiltration Level

Infiltration Level

Infiltration Level

Tgd

T cell CD4+ memory resting_CIBERSORT

ell CD4+ memory resting_CIBERSORT-A

T cell CD4+ Th1_XCELL

T cell regulatory (Tregs)_XCELL

Rho = - 0.259

p = 2.67e-02

Rho =- 0.244

p = 3.75e-02

Rho = 0.451

Rho =- 0.243

Th1

p = 6.10c-05

p = 3.81e-02

Th17

Th2

Treg

Act B

Imm B

0.0

0.1

0.2

0.3

0.4

0.00

0.05

0.10

0.15

0.00

0.05

0.10

0.04

Infiltration Level

Infiltration Level

Infiltration Level

0.00

0.01

0.02

0.03

0.05

Infiltration Level

Mem B

B cell_QUANTISEQ

Macrophage M2_QUANTISEQ

Macrophage M2_XCELL

Myeloid dendritic cell_MCPCOUNTER

Rho = 0.24

Rho =- 0.252

NK

p = 4.07e-02

Rho = - 0.421 p = 2.10e-04

p = 3.12e-02

Rho = - 0.286 p = 1.42e-02

CD56bright

CD56dim

MDSC

NKT

Act DC

0.000

0.025

0.050

0.075

0.100

0.00

0.05

0.10

0.00

0.02

0.04

0.06

0

30

60

90

120

1

Infiltration Level

Infiltration Level

Infiltration Level

Infiltration Level

pDC

NK cell_QUANTISEQ

Mast cell_XCELL

Mast cell activated_CIBERSORT-ABS

Rho =- 0.289

Rho = - 0.367

p = 1.41e-03

Rho = - 0.287

iDC

p = 1.30e-02

p = 1.39e-02

Macrophage

Eosinophil

Mast

Monocyte

Neutrophil

1

0.000

0.005

0.010

0.015

0.020

0.02

0.00

0.02

0.04

0.00

0.05

0.10

Infiltration Level

Infiltration Level

Infiltration Level

development. The expression of SULF2 was associated with multiple immune molecules. Based on our research results, SULF2 was related to several kinds of immunoinhibitors, such as PVRL2 (rho = 0.495, p = 4.74e-06), IL10RB (rho = 0.314, p = 0.00507) and CSF1R (rho = - 0.272, p = 0.0157) (Fig. 7A). Besides, SULF2 expression was related to immunostimulators, including PVR (rho = 0.454, p = 3.23e-05), TNFSF13 (rho = - 0.445, p = 4.7e-05), HHLA2 (rho = - 0.424, p = 0.000115) and CD28 (rho = - 0.387, p = 0.000465) (Fig. 7B). Therefore, it was suggested that SULF2 might be involved in facilitating immune surveillance escape of tumors.

3.6. Correlation of SULF2 expression with chemokines and receptors

Chemokines and receptors play important role in tumor immune process. Based on our results, SULF2 was related to chemokines and receptors. For example, SULF2 level was tightly related to CCL8 (rho = - 0.434, p = 7.72e-05), XCL1 (rho = - 0.332, p = 0.0029) and CCL2 (rho = - 0.264, p = 0.019) (Fig. 8A). Meanwhile, SULF2 expression was also closely associated with receptors, including CCR2 (rho = - 0.317, p = 0.0046), CCR6 (rho = - 0.348, p = 0.00179) and CXCR6 (rho = - 0.347, p = 0.00185) (Fig. 8B).

3.7. Diagnostic and prognostic significance of SULF2 for ACC

By integrating age, T stage, and gender, a nomogram model was constructed for predicting 3- and 5-year survival of ACC (Fig. 9A). When SULF2 expression was added to the nomogram model, it was found that the model could be used to guide the prediction of 2-, 3-, and 5-year survival probabilities of tumor patients. And the survival probability was significantly associated with SULF2 expression

A Immunoinhibitor

Fig. 7. The correlation of SULF2 expression with immunomodulators in ACC. (A) Correlation between the expression of SULF2 and immune in- hibitors through TISIDB database. (B) Correlation of SULF2 expression with immune stimulators in ACC available at TISIDB database. ACC, adrenocortical carcinoma.

ACC (79 samples)

ACC (79 samples)

ACC (79 samples)

ACC (79 samples)

ACC (79 samples)

.

2.5

7.5

4

6

6

CD244_exp

CD274_exp

0.0

CSF1R_exp

IL10RB_exp

5.0

IDO1_exp

0

3

-2.5

5

2.5

0

-4

-5.0

0.0

-3

4

4

SULF2_exp

6

8

4

6

8

4

6

8

4

6

8

4

6

SULF2_exp

Spearman Correlation Test: rho = - 0.274, p = 0.0147 ACC (79 samples)

SULF2_exp

8

Spearman Correlation Test: rho = - 0.261, p = 0.0206 ACC (79 samples)

Spearman Correlation Test: rho = - 0.272, p = 0.0157 ACC (79 samples)

SULF2_exp

Spearman Correlation Test: rho = 0.23, p = 0.0421 ACC (79 samples)

SULF2_exp

Spearman Correlation Test: rho = 0.314, p = 0.00507

6

8

9

2.5

3

KDR_exp

0.0

₹6

LAG3_exp

PVRL2_exp

TIGIT_exp

0

2.5

4

-3

-5.0

6

4

6

8

-6

SULF2_exp

4

SULF2_exp

6

8

4

SULF2_exp

6

8

4

Spearman Correlation Test: rho = - 0.242, p = 0.032

Spearman Correlation Test: rho = 0.278, p = 0.0132

Spearman Correlation Test: rho = 0.495, p = 4.74e-06

SULF2_exp

6

8

Spearman Correlation Test: rho = - 0.228, p = 0.0437

B Immunostimulator

ACC (79 samples)

ACC (79 samples)

ACC (79 samples)

ACC (79 samples)

ACC (79 samples)

4

2.5

2-

7.5

0.0

4

CD27_exp

CD28_exp

0

CXCL12_exp

HHLA2_exp

ICOSLG_exp

0.0

5.0

-2.5

-2

2.

-2.5

2.5

-4-

-5.0

-5.0

0

-6-

0.0

i

4

SULF2_exp

6

8

4

Spearman Correlation Test: rho = - 0.237, p = 0.036 ACC (79 samples)

SULF2_exp

6

8

4

Spearman Correlation Test: rho = - 0.387, p = 0.000465 ACC (79 samples)

SULF2_exp

6

8

4

8

4

Spearman Correlation Test: rho = - 0.254, p = 0.0241 ACC (79 samples)

SULF2_exp

6

Spearman Correlation Test: rho = - 0.424, p = 0.000115 ACC (79 samples)

SULF2_exp Spearman Correlation Test: rho = - 0.37, p = 0.000847

6

8

5.0

8-

6

6

2.5

IL2RA_exp

0.0

IL6R_exp

7

TNFSF13_exp

-4

PVR_exp

4

-2.5

2

6

2-

-5.0

0

5

4

SULF2_exp Spearman Correlation Test: rho = - 0.356, p = 0.00138

6

8

4

SULF2_exp

6

8

4

Spearman Correlation Test: rho = - 0.285, p = 0.0111

SULF2_exp Spearman Correlation Test: rho = 0.454, p = 3.23e-05

6

8

4

SULF2_exp Spearman Correlation Test: rho = - 0.445, p = 4.7e-05

6

8

(Fig. 9B). Based on TCGA database, univariate as well as multivariate regression revealed that SULF2 was positively correlated with HRs of ACC, and it was a valuable prognostic factor (Fig. 9C and D). According to the diagnostic ROC curve, SULF2 exhibited a good ability to discriminate tumor from healthy samples (AUC = 0.864) (Fig. 10A). Moreover, the time-dependent survival ROC curve based on SULF2 expression was used for predicting 1-, 3-, and 5-year survival of ACC cases. All these AUC values were found to be above 0.7, suggesting good predictive power of SULF2 expression (Fig. 10B). As revealed by KM curve analysis, ACC patients who had SULF2 up- regulation exhibited the poorer OS (p = 3.3e-05) and DFS (p = 0.00023) (Fig. 10C and D).

3.8. The association of the SULF2 expression level with drug sensitivity

Data regarding gene expression profiles along with drug sensitivity were collected in CellMiner. Thereafter, correlation coefficient of SULF2 level with drug sensitivity was determined by R language. Thereafter, 15 SULF2-related drugs were chosen based on R-value, as a result, SULF2 expression showed positive relation to tumor cell sensitivity to drugs like LY-2835219, Rapamycin, Everolimus, Midostaurin and Idelalisib, but the opposite was true in some drugs such as Fludarabine, DACARBAZINE and Raltitrexed (Fig. 11A-O). Therefore, it was speculated that SULF2 expression might help determine the sensitivity of certain drugs based on these results.

Fig. 8. Correlation between SULF2 expression and chemokine and receptor in ACC. (A) Correlation between the expression of SULF2 and che- mokine through TISIDB database. (B) Correlation of SULF2 expression with receptor in ACC available at TISIDB database. ACC, adrenocor- tical carcinoma.

A

Chemokine

ACC (79 samples)

ACC (79 samples)

ACC (79 samples)

ACC (79 samples)

ACC (79 samples)

7.5-

6

7.5

9

5.0

4

2.5

5.0

6

CCL2_exp

CCL3_exp

2

CCL5_exp

CCL8_exp

0.0

CCL14_exp

2.5

2.5

3

0

-2.5

0.0

0.0

0

-2

-5.0-

-2.5

-2.5

4

SULF2_exp Spearman Correlation Test: rho = - 0.264, p = 0.019 ACC (79 samples)

6

8

4

6

SULF2_exp

8

4

SULF2_exp

6

8

-3

4

6

4

6

Spearman Correlation Test: rho = - 0.239, p = 0.0342 ACC (79 samples)

Spearman Correlation Test: rho = - 0.222, p = 0.049 ACC (79 samples)

SULF2_exp

8

Spearman Correlation Test: rho = - 0.434, p = 7.72e-05

SULF2_exp Spearman Correlation Test: rho = - 0.283, p = 0.0118

8

2.5

7.5

0.0

0.0

CXCL12_exp

5.0

XCL1_exp

XCL2_exp

-2.5

-2.5

2.5

-5.0

-5.0

0.0

4

SULF2_exp

6

8

4

SULF2_exp

6

8

4

Spearman Correlation Test: rho = - 0.254, p = 0.0241

Spearman Correlation Test: rho = - 0.332, p = 0.0029

SULF2_exp

6

8

Spearman Correlation Test: rho = - 0.281, p = 0.0123

B Receptor

ACC (79 samples)

ACC (79 samples)

ACC (79 samples)

ACC (79 samples)

ACC (79 samples)

2.5

1

2.5

2.5

4

0.0

0

CCR1_exp

CCR2_exp

CCR6_exp

-1

CXCR2_exp

0.0

CXCR6_exp

0.0

2

-2.5

-2

-2.5

2.5

0

-3

-5.0

-5.0

-5.0

-2

-4

4

SULF2_exp

6

8

4

SULF2_exp

6

8

4

6

8

4

6

8

4

6

8

Spearman Correlation Test:

rho = - 0.273, p = 0.0151

Spearman Correlation Test: rho = - 0.317, p = 0.0046

SULF2_exp

Spearman Correlation Test: rho = - 0.348, p = 0.00179

SULF2_exp

Spearman Correlation Test: rho = - 0.224, p = 0.0478

SULF2_exp

Spearman Correlation Test: rho = - 0.347, p = 0.00185

4. Discussion

Nowadays, there are studies revealing the relationship between genes and tumors development [17,18]. The current research is the first to analyze SULF2 expression and its prognostic value of ACC through a series of bioinformatics approaches. Our study results suggested a possible link between high SULF2 expression and poor prognosis of ACC. In addition, this study also first suggested that SULF2 was strongly related to infiltration level of numerous immune-related molecules and cells in ACC. According to univariate as well as multivariate regression results, SULF2 expression was positively correlated with the HRs of ACC. Therefore, our research indicated the new and important functions of SULF2, which might affect the survival and prognosis of ACC patients by participating in immune infiltration.

SULF2, a member of sulfatase family, targets 6-O-sulfate groups on glucosamine residues in heparan sulfate (HS) chains while regulating a variety of molecular processes in the TME [19]. The signaling ligand-receptor interactions will be altered when the extracellular matrix (ECM) components of HS are affected by SULF2 [20]. Moreover, SULF2 can modify HS-mediated pathway by regulating HSPG expression [21,22]. Previous studies have shown that SULF2 expression increased within different tumor cells like bladder cancer, lung cancer and hepatocellular carcinoma, and that the high SULF2 expression level was related to poor prognosis [6, 23,24]. Until now, whether SULF2 is associated with tumor immunity and its specific significance in ACC remain unclear, which deserves further research.

First, SULF2 levels within ACC and normal tissues were investigated through TCGA, GEO, TIMER and GEPIA databases. As a result, SULF2 showed remarkably differential expression among tumor and healthy tissues in multiple human malignancies. Similarly, SULF2 expression notably increased in ACC compared with para-cancerous samples. Besides, the increased SULF2 expression was consistent with PD1, but unfortunately, there was no statistically significant relationship between them. According to these findings, SULF2 expression might be the possible auxiliary diagnostic reference for ACC. On the other hand, the up-regulated SULF2 expression level was markedly related to the poorer outcome of ACC in stages 1 and 2, 3, 4, N 0 and 1. Furthermore, based on KM plotter analysis, SULF2 up-regulation predicted the poor OS and DFS of ACC. The above results powerfully confirmed our hypothesis that SULF2 was

A

B

Points

0

20

40

60

80

100

Points

0

20

40

60

80

100

T stage

T3&T4

T stage

T3&T4

TI&T2

NI

T1

N stage

N stage

&T2

N1

NO

M

M stage

NO

M1

M stage

MO

MO

Female

Gender

Female

Gender

Age

Male

>50

Male

Age

50

Laterality

50

eft

Laterality

-50

Len

SULF2

Right

High

Right

Low

Total Points

Total Points

0

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80

120

160

200

Linear Predictor

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40

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280

Linear Predictor

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1

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2.5

3-year Survival Probability

1

2

2-year Survival Probability

2.5

-1.5

0.5

0.5

1.5

3-year Survival Probability

0.8

0.6

0.4

0.2

5-year Survival Probability

0.8

0.6

0.4

0.2

0.4

5-year Survival Probability

0.8

0.6

0.4

0.2

0.8

0.6

0.2

0.8

0.6

0.4

0.2

C

D

0

10

20

30

0

5

10

15

20

CharacteristicsTotal(N)HR(95% CI)P valueCharacteristicsTotal(N)HR(95% CI)P value
T stage77T stage77
T19ReferenceT19
T2422.444 (0.305-19.596)0.4T2421.897 (0.232-15.531)0.551
T3812.439 (1.300-118.988)0.029T385.778 (0.554-60.221)0.142
T41830.506 (3.595-258.857)0.002T41817.511 (1.797-170.675)0.014
N stage77N stage77
NO68ReferenceNO68
N192.038 (0.769-5.400)0.152N19
M stage77M stage77
MO62ReferenceMO62
M1156.150 (2.710-13.959)<0.001M1150.709 (0.249-2.013)0.518
Age79Age79
<= 5041Reference<= 5041
>50381.799 (0.846-3.824)0.127>5038
Gender79Gender79
Female48ReferenceFemale48
Male311.001 (0.469-2.137)0.999Male31
SULF2792.015 (1.492-2.722)<0.001SULF2791.759 (1.237-2.503)0.002

Fig. 9. Nomogram and Cox hazard analysis of SULF2 in ACC. (A) Nomogram model, based on clinicopathologic factors to predict survival prob- ability at 3-, and 5-years. (B) Nomogram model, integrating clinicopathologic factors and SULF2 level to predict survival probability at 2-, 3-, and 5- years. (C) Single-factor cox analysis of ACC. (D) Multivariate cox analysis of ACC.

likely to be a prognostic biomarker in ACC. SULF2 expression performed well in distinguishing cancer from healthy samples and predicting the long-term survival rates, suggesting that it was the possibly useful biomarker used to diagnose and predict the prog- nostic of ACC.

GPC3, NDST1 and COPE were identified as the functional partner genes for SULF2. As revealed by our GO and KEGG analyses, they were enriched in heparan sulfate proteoglycan metabolic process, glycosaminoglycan biosynthesis-heparan sulfate/heparin, and heparan sulfate sulfotransferase activity. Previous studies have clearly stated that extracellular vesicle-mediated communication is very important for pathological process in tumor [25]. Many important extracellular vesicle-mediated communication processes like uptake and biogenesis, are under the regulation of HSPG [26]. Based on these results, it is reasonable to believe that GPC3, NDST1, COPE and SULF2 have important synergistic roles in the pathogenesis of ACC. Further, our GSEA results showed that neuroactive ligand receptor interaction and reactome g alpha I signaling events pathways were obviously enriched by these genes. Studies reveal that neuroactive ligand receptor interaction is associated with diffuse intrinsic pontine glioma and granulosa cell tumor development [27,28]. Therefore, the neuroactive ligand receptor interaction may be linked with ACC pathogenesis. Additionally, infiltration of immune cells has a key role in carcinogenesis [29]. SULF2, a novel immunomodulators, has positive modulatory effects on antigen delivery and cytophagy of immune cells [30]. Xuping Niu et al. discovered that SULF2 was up-regulated in dermal mesenchymal stem cells, which affected the inflammatory microenvironment via multiple pathways, including regulation of immune cell proliferation, differentiation, migration and recruitment [31,32]. But so far, it remains unknown whether SULF2 expression is involved in immune infiltration in ACC. This study first illustrated that SULF2 was related to immune infiltration level in ACC. Based on our analyses, SULF2 expression was obviously correlated with immune cells like CD4+T cells, CD8+ T cells, and NK cell. Meanwhile, the increased SULF2 expression was related to diverse kinds of immuneinhibitors, immunestimulators, chemokines and receptors suggesting that SULF2 had a critical effect on immune regulation in ACC. According to our PPI network and functional annotation results, SULF2 and interacting genes were related to the underlying tumor biological processes and contributed to tumorigenesis and progression. Besides, PD1, an important immune checkpoint component, has been recognized as an important target for tumor immunotherapy [33,34]. This study disclosed that SULF2 expression was associated with PD1 and immune-related receptors and molecules. Therefore, immunotherapy may be useful for ACC and more efforts are needed to explore the molecular mechanism. On the other hand, we found that TP53 mutation status was related to tumor development and prognostic outcome [35,36]. Moreover, SULF2 levels remarkably increased in ACC patients with TP53 mutation compared with in non-mutated cases, with the difference being statistically significant. It suggests that there may be a link between SULF2 and TP53, which deserves further study. Finally, SULF2 expression was markedly related to several drugs, which provides some guidance for clinical treatment of the disease.

Nonetheless, certain limitations should be noted in this analysis. For example, the data were mostly sourced from online databases

Fig. 10. ROC analysis and Kaplan-Meier survival curves. (A) The ROC curve of diagnosis to distinguish tumor from normal tissue. (B) Time- dependent survival ROC curve analysis to predict 1-, 3- and 5-year survival rates. (C, D) The overall survival and disease-free survival curves comparing patients with high and low SULF2 expression in ACC.

A

B

1.0

1.0

0.8

0.8

Sensitivity (TPR)

Sensitivity (TPR)

0.6

0.6

0.4

0.4

0.2

SULF2

SULF2

0.2

1-Year (AUC = 0.818)

AUC: 0.864

3-Year (AUC = 0.781)

0.0

CI: 0.800-0.928

0.0

5-Year (AUC = 0.844)

0.0

0.2

0.4

0.6

0.8

1.0

0.0

0.2

0.4

0.6

0.8

1.0

1-Specificity (FPR)

1-Specificity (FPR)

C

Overall Survival

D

Disease Free Survival

1.0

LOW SULF2 TPM

1.0

High SULF2 TPM

Low SULF2 TPM

Logrank p=7.6e-07

High SULF2 TPM

Logrank p=8.1e-05

0.8

HR(high)=11

p(HR)=3.3e-05

0.8

HR(high)=3.9

n(high)=38

p(HR)=0.00023

Percent survival

Percent survival

n(high)=38

0.6

n(low)=38

0.6

n(low)=38

0.4

0.4

0.2

0.2

0.0

0.0

0

50

100

150

0

50

100

150

Months

Months

and our results might be affected by subsequent data updates, which might possibly introduce bias. Besides, because of the rarity of the disease, not enough cases were obtained to complete the experimental validation.

5. Conclusion

According to our results, SULF2 shows abnormal expression in ACC, which predicts the dismal prognostic outcome. Meanwhile, this study is the first to illustrate that SULF2 expression is closely related to immune system, indicating its possible involvement in immune infiltration of tumors, which sheds novel lights on diagnosing and treating ACC.

Author contribution statement

Jiusong Yan and Xiaodu Xie: Conceived and designed the experiments; wrote the paper. They are co-first authors.

Qinke Li and Peihe Liang: Performed the experiments; analyzed and interpreted the data.

Junyong Zhang and Guangyong Xu: Contributed reagents, materials, analysis tools or data. They were responsible for the final review of the paper who are co-corresponding authors of this paper.

Funding statement

The research was funded by the Natural Science Foundation of Chongqing (2022NSCQ-MSX0283).

Fig. 11. The relationship between SULF2 expression levels and drug sensitivity. (A-O) The correlation between SULF2 expression and Fludarabine, LY-2835219, Rapamycin, Everolimus, Midostaurin, DACARBAZINE, Idelalisib, IPI-145, Copanlisib, Abiraterone, 6-MERCAPTOPURINE, RAPAMY- CIN, Cladribine, Raltitrexed and Irofulven.

A

SULF2, Fludarabine Cor =- 0.382, p=0.003

B

SULF2, LY-2835219 Cor=0.351, p=0.006

C

SULF2, Rapamycin

D SULF2, Everolimus Cor=0.340, p=0.008

Cor=0.346, p=0.007

·

2

.

1.0

··

..

1

2

1

0.5

1

0.0

0

0

0

-1

-0.5

-1

-1.0

-1

-2

0

2

4

6

0

2

4

6

0

2

4

6

0

2

4

6

E

SULF2, Midostaurin

F

SULF2, DACARBAZINE

G

SULF2, Idelalisib

H

SULF2, IPI-145 Cor=0.288, p=0.026

Cor=0.315, p=0.014

Cor =- 0.314, p=0.015

Cor=0.294, p=0.023

2

2

:

3

·

:

2

0

1

2

1

..

1

-2

0

0

0

-1

-1

-1

0

2

4

6

0

2

4

6

0

2

4

6

0

2

4

6

I

SULF2, Copanlisib

SULF2, Abiraterone

Cor=0.277, p=0.032

J

Cor=0.271, p=0.037

K

SULF2, 6-MERCAPTOPURINE Cor =- 0.266, p=0.040

L SULF2, RAPAMYCIN Cor=0.265, p=0.041

··

1.5

1.0

..

..

1

1.0

1

0.5

:

0

0.5

0.0

0

0.0

-1

-0.5

-1

-0.5

-2

-1.0

-2

-1.0

-1.5

0

2

4

6

0

2

-1.5

4

6

0

2

4

6

0

2

4

6

M

SULF2, Cladribine Cor =- 0.259, p=0.046

N

SULF2, Raltitrexed Cor =- 0.256, p=0.048

0

SULF2, Irofulven

Cor=0.256, p=0.049

2

2.

2

2

1

1

0

0

0

-2

-1

..

-4

-1

0

2

4

6

0

2

4

6

0

2

4

6

Data availability statement

Data can be obtained from corresponding authors upon on request.

Declaration of interest statement

All authors declared no competing interest.

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