Mutations in Adrenocortical Tumors
M. Reincke
Division of Endocrinology, Medical Department II, University of Freiburg, Germany
Silent and incidentally detected adrenocortical neoplasms are the most frequent abnormality of the adrenal cortex. The prevalence of these lesions in the general population is around 1%, increases with age and reaches 6% in the seventh decade of life. Primary adrenocortical carcinoma, on the other hand, a highly malignant tumor, is rare with an incidence of 1.7 cases per million per year. Recent progress has been achieved in the understanding of adrenocortical tumorigenesis by mapping and identification of genes responsible for hereditary tumor syndromes like the Li-Fraumeni syndrome, Beckwith-Wiede- mann syndrome, Carney complex and the Multiple Endocrine Neoplasia Type I. Investigation of the clonal composition of adrenal tumors demonstrates that adrenal carcinomas are gen- erally monoclonal, whereas adrenal adenoma may be polyclo- nal in approximately 25% of cases. These adenomas may have a multicellular origin under the putative action of extra-adrenal and local growth factors. Oncogenes and tumor suppressor genes involved in adrenal carcinomas include mutations in the p53 tumor suppressor gene and rearrangements of the chro- mosomal locus 11 p15.5 associated with IGF II hyperexpression. Constitutive activation of the ACTH receptor-G protein-cAMP signal cascade does not play a role in adrenal tumor formation. Conversely, deletions of the ACTH receptor gene have been re- cently found in undifferentiated adenomas and in aggressive adrenocortical carcinomas. This indicates that the signaling pathways responsible for adrenocortical tumor formation are different from that of other endocrine neoplasms like pituitary — d thyroid adenomas.
Key words: Adrenocortical Adenoma - Adrenocortical Carci- noma - Oncogene - Tumor Suppressor Gene - Tumorigenesis - Steroidogenesis
Introduction
Primary adrenocortical tumors are divided into benign and malignant groups. Benign, clinically silent adrenocortical ade- nomas are extremely frequent, as shown by autopsy studies and cross-sectional studies by abdominal CT (1). The frequen- cy of these so-called incidentalomas gradually increases with age, ranging from 3.0 to 7.0 percent in adults over 50 years
(2). Usually they are discovered incidentally in the context of abdominal CT or ultrasound scans performed for various unre- lated reasons. The majority of these tumors are nonfunctional adrenal adenomas, and the pathogenesis of these lesions is lar- gely unknown (3). Adrenocortical carcinoma, on the other hand, is a highly malignant rare tumor, accounting for 0.05 - 0.2% of all cancers, with an approximate incidence of 1.7 new cases per million/year (4). Seventy percent of the patients suf- fer from an advanced tumor stage with local invasion or dis- tant metastasis at the time of diagnosis and can rarely be cured (5).
Recently, there has been considerable progress in the under- standing of adrenal tumorigenesis. Studies using the “candi- date gene approach” showed a low prevalence of mutations in tumor suppressor genes and oncogenes in adenomas. Muta- tions in G-protein-coupled receptors and G-proteins identified in growth-hormone secreting pituitary tumors and thyroid adenomas have not been found in adrenal cortex neoplasms. This supports the concept that the signal transduction cascade controlling tumor growth in adrenocortical neoplasms is dif- ferent from that of pituitary and thyroid tumors. More recent- ly, there have been reports of a high frequency of mutations in- volving the IGF-II locus at 11 p15.5, the p53 tumor suppressor gene at 17 p and the ACTH receptor gene at 18 p21.1. This re- view will focus on the recent developments in the field of adrenal tumorigenesis with a special emphasis on adrenal- specific mechanisms of cancer development.
Hereditary Tumor Syndromes
Several hereditary tumor syndromes are associated with for- mation of benign or malignant adrenocortical tumors (Ta- ble 1).
Li-Fraumeni syndrome
The Li-Fraumeni syndrome was first described in 1969 (6). It is a rare family tumor syndrome with high incidence of breast cancer, leukemias, soft tissue sarcomas, gliomas and adreno- cortical carcinomas. Affected patients generally develop the first tumor before the age of 30, and second and third neopla-
| Clinical characteristics | Molecular defect | |
|---|---|---|
| Li-Fraumeni syndrome | Familial susceptibility to a variety of cancers including breast and adrenal cancers, gliomas, sarcomas | Germ-line mutations in the p53 tumor suppressor gene (17 p) |
| Beckwith-Wiedemann syndrome MEN 1 | Neonatal macrosomia, macroglossia, omphalocele Hyperparathyroidism, neuroendocrine gut tumors, pituitary adenomas | Allelic loss of 11 p15 (Tumor sup- pressor genes H19 and P57KIP2) Germ-line mutations in the me- nin gene (11 q13) |
| Carney's complex | PPNAD, atrial myxomas, swannomas, lentigines, blue naevi of the skin/mucosa | 2 p16 (Carney locus) |
| Congenital adrenal hyperplasia | Female/male pseudohermaphro- ditismus, cortisol deficiency, mineralocorticoid deficiency or excess | Inborn errors of cortisol bio- synthesis enzymes resulting in chronic ACTH hypersecretion |
sias are frequently observed, especially in patients previously treated with chemotherapy or irradiation (7). The molecular basis of this disease has been recently elucidated by identifica- tion of germ-line point mutations in the p53 tumor suppressor gene (8, 9). The second p53 allele is inactivated in tumor tissue by deletion of the short arm of chromosome 17 (17 p) eliminat- ing all wild-type p53 activity (10). Recently, p53 germ-line mutations have been found in children with adrenocortical carcinomas without a classical family history of the Li-Frau- meni syndrome (11,12). Because of the consequences of germ-line p53 mutations for these individuals and their rela- tives, genetic testing has been recommended for risk assess- ment in childhood adrenocortical carcinoma.
Beckwith-Wiedemann syndrome (BWS)
The BWS is a rare condition (1/13.700 live birth) characterized by macroglossia, gigantism, earlobe pits or creases, abdominal wall defects, and an increased risk for the development of Wilms tumors of the kidney, rhabdomyosarcoma, hepatoblas- toma, and adrenal carcinoma (13,14). Although most BWS cases are sporadic, families have been reported in which the disease segregates as an autosomal dominant trait with in- complete penetrance. BWS maps to chromosome 11 p15.5 (15). Uniparental paternal isodisomie for this locus, which in- duces the ICF-II gene, has been identified in affected individ- uals (16). The complete loss of one IGF-II allele and a duplica- tion of the remaining allele in association with IGF-II overex- pression has been demonstrated in tumors of the BWS and in sporadic adrenocortical tumors (16,17).
Multiple endocrine neoplasia type 1
The genetic defect responsible for multiple endocrine neopla- sia Type 1 (MEN 1) has been mapped to chromosome 11 q13 (18). Tumorigenesis results from unmasking of a recessive mu- tation in the recently identified menin tumor suppressor gene with development of parathyroid adenomas, pituitary adeno- mas and tumors of the endocrine pancreas (19). Involvement of the adrenal gland has been reported in a considerable pro- portion of patients (36-41%) with MEN 1. This lesion is often characterized as bilateral hyperplasia or adenomas, and occa- sionally even carcinomas (20). Recently, in 12 patients with
adrenocortical tumors out of a series of 33 patients with MEN 1, loss of constitutional heterozygosity for chromosome 11 q13 was only demonstrated in a patient with adrenocortical carci- noma, but not in 11 patients with benign adrenal lesions (20). This suggests, that adrenocortical tumorigenesis is probably not a primary lesion in the MEN 1 syndrome. In the same study, insulin- or proinsulin-secreting pancreatic endocrine tumors were significantly overrepresented in patients with MEN 1 and adrenal tumors, suggesting that adrenocortical tu- morigenesis may be stimulated by insulin and insulin-related peptides in these patients.
Familial hyperaldosteronism type II (FH-II)
Familial hyperaldosteronism Type I is characterized by pri- mary hyperaldosteronism with hypertension and hypokali- emic alkalosis which responds to dexamethasone treatment (21). The genetic basis recently elucidated is a hybrid gene which involves the fusion of the regulatory region of the CYP11 B1 gene encoding 11 ß-hydroxylase with the coding re- gion of another gene (Cyp11 B2) encoding aldosterone syn- thase (22). Whereas tumor formation has been rarely de- scribed in FH-I (23), Stowasser et al. (24) recently reported five families with familial occurrence of primary hyperaldosteron- ism that was not glucocorticoid-suppressible, but was associ- ated with aldosterone-producing adenomas or bilateral adre- nal hyperplasia. The genetic basis of this so-called familial hy- peraldosteronism Type II has not yet been elucidated.
Carney complex
The Carney complex, an autosomal dominant disorder, is char- acterized by the association of primary pigmented nodular adrenocortical disease, myxomas, particularly of the heart, and psammomatous melanotic swannomas involving the pe- ripheral nervous system, spotty pigmentation and blue naevi of the skin or mucosa, and diverse endocrine neoplasms (25). Testicular Sertoli cell tumors, GH-producing adenomas, thy- roid follicular carcinomas, ovarian cysts, and adrenocortical tumors were associated with this familiar syndrome, whose chromosomal locus was recently mapped on 2 p16 (25), but whose pathophysiological mechanisms remain unknown.
Congenital adrenal hyperplasia
Long-standing excess of ACTH and related peptides is associ- ated with the development of nodular adrenal hyperplasia. Macronodular adrenal disease has been observed in 17 to 40% of patients with ACTH-dependent Cushing’s syndrome (26, 27). Also, congenital adrenal hyperplasia (CAH) can cause adrenocortical nodular hyperplasia. 80% of patients with clas- sical 21-hydroxylase deficiency have uni- or bilateral nodular adrenal hyperplasia (28,29). Macronodular adrenal disease in patients with CAH is generally clinically silent, but functional adrenal neoplasms, mainly androgen-secreting tumors, have been described in patients with CAH (30). Interestingly, 45% of heterozygote relatives of patients with 21-hydroxylase defi- ciency also have macronodular adrenal disease (29), although ACTH and POMC peptides are not elevated in these subjects. This raises the question whether mild 21-hydroxylase defi- ciency, which has a prevalence of 1 : 50 in the general popula- tion, may be responsible for the formation of adrenal “inciden- talomas”. However, a role of 21-hydroxylase deficiency in the pathogenesis of adrenal tumors was excluded in a recent study of incidentalomas patients. Only 1 of 20 subjects was shown to have a heterozygous germline mutation, whereas the other subjects did not have mutations in 21-hydroxylase gene (31).
Proto-Oncogene
Tumor Suppressor Gene
Senescence
Differentiation
Apoptosis
Death
Death
Death
Clonal Analysis of Adrenocortical Tumors
Determination of the clonal composition of neoplastic tissues has been instrumental in establishing the cellular origin of many human tumors (32). The pathogenesis of cancer is a mul- tistep process, during which an initiation event is followed by tumor promotion (33). The initiation event is widely regarded as a somatic mutation occurring in oncogenes or tumor sup- pressor genes (Fig. 1). This gives a single cell a selective growth advantage which, by means of clonal expansion, produces a monoclonal tumor. Adrenocortical steroid secretion is a com- plex process that is regulated by several hormones and growth factors, which also controls adaptive processes like hypertro- phy and hyperplasia of the adrenal cortex. A polyclonal tumor would favor the idea that it developed from a group of cells un- der the common stimulus of growth factors of extra- or intra- adrenal origin. Conversely, a monoclonal tumor would suggest that it developed from a single genetically aberrant cell. Three recent publications investigated the clonal composition of adrenocortical tumors using X-chromosome inactivation anal- ysis (34-36) (Table 2). Gicquel et al. (34) found a monoclonal pattern in all 4 carcinomas studied. Of 14 benign adenomas, 6 tumors were monoclonal, whereas 4 adenomas clearly showed a polyclonal pattern. The study of Beuschlein et al. (35) re- vealed monoclonality in all carcinomas (n=3) and in 7 of 8 adenomas. One cortisol-producing adenoma in this study was polyclonal. These data demonstrate that adrenocortical carci- nomas are generally monoclonal as the result of oncogenic mutations of single cells with transformation and expansion into a malignant clone. Most of the adenomas also arise from oncogenic mutations, whereas a minority of benign adenomas is genetically heterogeneous. These adenomas may have an oligo- or multicellular origin under the putative action of ex- tra-adrenal or local growth factors. However, monoclonal and polyclonal adenomas might represent different stages of a common multistep process (37). In this notion, the growth of polyclonal tumor tissue arise either from the proliferation of cells with a constitutive intrinsic growth potential or by stimu- lation of mitogens, followed by a secondary mutational event conferring a growth advantage of a particular clone leading to monoclonality.
| Monoclonality | Polyclonality | Ambigous Results | |
|---|---|---|---|
| Gicquel et al. (34) | |||
| adenomas (n = 14) | 6/14 | 4/14 | 4/14 |
| carcinomas (n = 4) | 4/4 | 0/4 | 0/4 |
| Beuschlein et al. (35) | |||
| adenomas (n = 8) | 7/8 | 1/8 | 0 |
| carcinomas (n = 3) | 3/3 | 0/0 | 0 |
| Rico et al. (36) | |||
| adenomas (n =7) | 5/7 | 1/7 | 1/7 |
| carcinomas (n = 7) | 7/7 | 0/7 | 0 |
| Total | |||
| adenomas (n = 29) | 18/29 (62%) | 6/29 (21%) | 5/29 (17%) |
| carcinomas (n = 14) | 14/14 (100%) | 0/0 (0%) | 0/0 (0%) |
Table 2 Clonal composition of adreno- cortical tumors: Review of the literature.
Cytogenetic Aspects of Adrenocortical Tumorigenesis
The genetic aberrations involved in sporadic primary adreno- cortical tumors are not completely understood. Previous stud- ies have focused on selected chromosome regions. Yano et al. studied loss of heterozygosity in one primary and 8 recurrent adrenocortical carcinomas and 8 sporadic benign lesions (38). The carcinomas showed loss of heterozygosity on 17 p, 11 p and 13 q. No genetic changes were found in any of the benign le- sions. Karyotype analysis of two sporadic adrenocortical carci- nomas have revealed alterations at 11 p (39,40). In 5 of 12 al- dosterone-producing adenomas, abnormal karyotypes involv- ing loss of chromosome Y (n=5), loss of chromosome 19 (n=1), and partial trisomy 7 q were found (41). Using fluores- cence in situ hybridization trisomy of chromosome 1, 8, 11, 12, and 15 was detected in an adrenocortical carcinoma (42). More recently, using comparative genomic hybridization (CGH), a high frequency of genetic aberrations was detected in adreno- cortical carcinomas (43). Losses most often involved the chro- mosomal regions 2, 11q, and 17 p (four of eight tumors),
whereas gains took place at chromosome 4 and 5 (four of eight tumors). These results differ from our own experience using CGH in 7 adenomas and 14 carcinomas (44). Chromosomal gains were much more prevalent than losses and affected chromosomes 16 p, 20q (each 11/14 tumors), 5, 7, 9q, 12q, 14q (each 7/14 tumors) (Fig. 2). Losses were mainly found at 9 p. Total gains and losses were less frequent in large adeno- mas (tumor diameter > 4.0 cm) and absent in small adenomas (<4 cm). These studies show that adrenal carcinoma tumori- genesis involves amplifications of chromosomes not common- ly affected in other human tumors indicating the presence of new and possibly adrenal-specific oncogenes. This may give new insight into the mechanisms of adrenocortical tumori- genesis.
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Oncogenes and Tumor Suppressor Genes
ACTH receptor mutations and adrenal tumors
Cyclic AMP is a key second messenger involved in both hor- mone hypersecretion and/or increased cell proliferation in a variety of endocrine tissues. Constitutive activation of key reg- ulatory proteins of cAMP, such as G-protein-coupled receptors and GTP binding proteins, have been implicated in the patho- genesis of such diseases as acromegaly and toxic thyroid ade- nomas (45,46). Oncogenic transformation of the TSH receptor gene by point mutations was found in approximately 30% of hyperfunctioning thyroid adenomas (46). These mutations caused amino acid substitutions in the carboxy-terminal por- tion of the third cytoplasmic loop of this receptor in 3 of 11 hy- perfunctioning thyroid adenomas. The mutant receptors con- ferred constitutive activation of adenylyl cyclase, when tested by transfection in COS cells. An alternative pathway increasing intracellular cAMP and associated with tumorigenesis are con- stitutive activating mutations in the o-chain of the stimulatory G-protein (Gs) found in growth hormone-producing adenomas and thyroid adenomas (45). The mutant G-proteins in these tumors remain in the activated state, stimulating the adenylyl cyclase and, hence, cAMP production.
Adrenocortical tumorigenesis differs from pituitary and thy- roid tumorigenesis, as activation of the cAMP/protein kinase A pathway seems to be of little importance in the development of adrenocortical neoplasms. ACTH is the main hormone regu- lating steroid hormone secretion, however, it fails to cause adrenocortical hypertrophy in the absence of innervation by the splanchnic nerve. ACTH in physiologic concentrations does not stimulate cell proliferation of adrenocortical cells in vitro, and even pharmacologic doses of ACTH induce only a moder- ate cell growth (47). In keeping with these findings, activating mutations of neither the ACTH receptor nor the a-chain of the Gs have been identified in benign or malignant adrenocortical tumors (45,48-51). On the contrary, activating mutations of the Gi2, one of the adenylyl cyclase inhibitory G-proteins, were found in very few adrenocortical tumors, but not in a variety of other endocrine and non-endocrine tumors (45,50,51).
These data suggest that, in the adrenal cortex, the ACTH/Gs/ protein kinase A signaling pathway is preferentially important for steroid hormone secretion and, hence, maintenance of a highly differentiated cellular phenotype, but is of relatively low importance for cellular proliferation. This is supported by the recent finding of deletions of the ACTH-R gene in undiffer- entiated adrenocortical tumors. Of 16 patients with benign le- sions, mutational loss of the ACTH-R gene by deletion was present in one oncocytic non-functional adenoma, but not in 15 hyperfunctioning adenomas. Of 4 informative patients with adrenocortical carcinomas, loss of heterozygosity of the ACTH receptor gene was present in 2 cases. Both patients had ad- vanced tumor stages and showed a more rapid course than carcinoma patients without LOH. Northern blot experiments showed reduced expression of ACTH-R mRNA in the tumors with LOH of the ACTH-R gene, suggesting functional signifi- cance of this finding at the transcriptional level (52). These data demonstrate that the ACTH receptor may act as a tumor suppressor gene. Allelic loss of the ACTH-R gene in adrenocor- tical tumors can result in loss of differentiation, a characteris-
tic feature of human tumorigenesis which is associated with clonal expansion of a malignant cell line.
IGF II, p53, and other oncogenes
Using the “candidate gene approach”, several studies have in- vestigated the prevalence of putative adrenal oncogenes and tumor suppressor genes (Table 3). Most of these studies showed a low prevalence of mutations. However, IGF II overex- pression and mutations in the p53 tumor suppressor gene have frequently been demonstrated in adrenocortical carcino- mas.
IGF II, H19 and p57KIP2
IGF-II overexpression is frequent in adrenocortical tumors (see for review (37)), particularly in adrenocortical carcinomas (84%) compared to adenomas (6%), strongly suggesting a de- terminant role for this factor in tumor progression and/or aquisition of the malignant phenotype. IGF-II overexpression has been demonstrated at the mRNA and at the protein level, and both receptors for IGF-I and IGF-II are present in adreno- cortical tumors (59,64). Thus, all components of the machin- ery required for auto- and paracrine action of IGF’s are present in adrenocortical tumors. Structural abnormalities of the IGF-II gene locus at chromosome 11 p15 is frequently demonstrable in adrenal carcinomas (17). The IGF-II gene is maternally im- printed with the sole expression of the paternal allele. Nearly 80% of all carcinomas show loss of constitutive heterozygosity of the 11 p15 region, probably by paternal isodisomy. However, the genetic events causing IGF-II hypersecretion appear to be heterogeneous and complex, involving additional mechanisms like loss of maternal imprinting of the IGF-II gene and changes in the putative IGF-II repressor H19 (37). Abnormalities of the 11 p15 region are a good marker of malignancy present in 27 of 29 carcinomas but only in 3 of 35 adenomas (58). Liu et al. (63) recently demonstrated that hyperexpression of IGF-II mRNA in adrenocortical carcinomas was paralleled by low expression of H19 and p57KIP2, another genomically imprinted putative tu- mor suppressor gene located at 11 p15.5. In contrast, cortisol- and aldosterone-secreting adenomas had normal IGF-II, H19 and p57KIP2 mRNA levels. Androgen-secreting adenomas showed an expression pattern similar to that of carcinomas. This suggests that alterations of H19 and p57KIP2 gene expres- sion are involved in the tumorigenesis of adrenocortical neo- plasms, especially carcinomas and androgen-secreting adeno- mas.
p53 tumor suppressor gene
Mutations in the p53 tumor suppressor gene are the most common genetic alterations in humans identified to date (7,64). The p53 gene functions as a tumor suppressor gene, and more specifically as a cell cycle regulator. Inactivation of p53 by point mutations and/or deletions results in loss of tu- mor suppressor function. p53 mutations are rarely observed in benign tumors, are generally a late event in tumorigenesis, and are associated with a malignant phenotype (65-67). More than 90% of p53 mutations found in human tumors are located within exon 5 to 8 (68). These exons contain four highly con- served domains essential for a normal function of the protein. Mutations outside these areas are scattered throughout the re- maining exons, and their pathophysiological significance has
| Gene | Prevalence of Mutations | Author | Year |
|---|---|---|---|
| Signal transduction | |||
| constitutive activating | 0/25 tumors | Latronico et al. (48) | 1995 |
| ACTH receptor mutations | 0/16 tumors | Light et al. (49) | 1995 |
| ACTH receptor deletions | 1/16 adenomas | ||
| 2/4 carcinomas | Reincke et al. (52) | 1997 | |
| constitutive activating angiotensin li | 0/55 adenomas | ||
| type 1 receptor mutations | 0/1 carcinoma | Sachse et al. (53) | 1997 |
| G-Protein mutations (Gas) | 0/11 tumors | Lyons et al. (45) | 1990 |
| 0/18 tumors | Reincke et al. (50) | 1993 | |
| G-Protein mutations (Gai2) | 3/11 tumors | Lyons et al. (45) | 1990 |
| 0/18 tumors | Reincke et al. (50) | 1993 | |
| 0/18 tumors | Gicquel et al. (51) | 1995 | |
| Calcium-dependent proteinkinase C activity | Normal in 17/17 tumors | Latronico et al. (54) | 1994 |
| Ras mutations | 0/17 tumors | Moul et al. (55) | 1993 |
| 0/33 tumors | Ohgaki et al. (56) | 1993 | |
| 3/24 carcinomas (N-ras) | Yashiro et al. (57) | 1994 | |
| 4/32 adneomas (N-ras) | |||
| Growth factors | |||
| IGF Il overexpression | 27/29 carcinomas | ||
| /LOH 11 p15 | |||
| 3/35 adenomas | Gicquel et al. (16,57) | 1997 | |
| IGF Il overexpression | 5/6 carcinomas | ||
| 0/15 adenomas | Ilvesmäki et al. (59) | 1993 | |
| Tumor Suppressor Genes | |||
| p53 exon 4 | 11/15 adenomas | Lin et al. (60) | 1994 |
| 0/19 adenomas | Reincke et al. (61) | 1996 | |
| p53 exon 5-8 | 3/15 carcinomas | Ohkagi et al. (56) | 1993 |
| 0/18 adenomas | |||
| 5/13 carcinomas | Reincke et al. (62) | 1994 | |
| 0/5 adenomas | |||
| p57KIP2 and H19 | low expression in | Liu et al. (63) | 1997 |
| 3/10 adenomas | |||
| 6/6 carcinomas |
Table 3 Mutations in oncogenes and tumor suppressor genes in adrenal tumors.
been a matter of some debate (69). Several lines of evidence suggest that mutant p53 is involved in adrenal tumorigenesis. First, allelic loss of the chromosomal locus of the p53 gene, 17 p, has been demonstrated by Yano et al. in adrenal carcino- mas but not in adenomas (38). Second, the above mentioned Li-Fraumeni syndrome which is caused by germ-line p53 mu- tations is associated with development of adrenocortical carci- nomas (8,9). Third, we and others recently identified p53 mu- tations in approximately 30% of sporadic adrenal carcinomas (56,62).
Recently, in a study from Taiwan Lin et al. reported a new mu- tational hot spot within exon 4 in benign adrenal tumors, with 9 of 15 (60%) adenomas having evidence for p53 mutations by SSCP (60). Sequencing confirmed the presence of point muta- tions at codon 100, 102, or 104, within exon 4. We re-examined the prevalence of p53 mutations in exon 4 and could not find
any mutation in a large series of 27 tumors from Europe and the US (61). This casts considerable doubt on the significance of the finding of Lin et. al., which are, most likely, explained by geographic differences or technical factors.
In summary, recent progress in the understanding of adrenal tumorigenesis shows that the genetic events associated with adrenocortical carcinoma involve loss of heterozygosity at chromosome 11 p, 13 q and 17 p, and amplification of chromo- somal areas 5, 7, 9, 12, 16, 22. Rearrangements of 11 p15/IGF II hypersecretion is often present in adrenal cancer, whereas p53 mutations and ACTH receptor deletions seem to be a late event in cancer formation associated with a malignant phenotype (Fig. 3). The majority of adrenal adenomas is monoclonal in cell composition, however, the genetic events involved in clo- nal expansion and hormone excess remain to be elucidated.
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Normal Adrenal
· LOH at 11p, 11q, 13q, 17p
· Amplification of chrom. 5, 7, 9q, 12q, 14q, 16p
· IGF II overexpression
Adrenal Carcinoma
· p53 point mutations
· ACTH receptor deletion
Invasion/Metastases
Acknowledgements
Supported by a grant of the Wilhelm Sander Stiftung, Mün- chen, to M.R.
References
1. Kloos RT, Gross MD, Francis IR, Korobkin M, Shapiro B. Inciden- tally discovered adrenal masses. Endocr Rev 1995; 16: 160-83
2. Latronico AC, Chrousos GP. Extensive personal experience: Adrenocortical tumors. J Clin Endocrinol Metab 1997; 82: 1317-24
3. Reincke M, Allolio B. Das Nebenniereninzidentalom: Die Kunst der Beschränkung in Diagnostik und Therapie. Dtsch Ärzteblatt [A] 1995; 92: 764-70
4. Lipsett MB, Hertz R, Ross GT. Clinical and pathophysiologic as- pects of adrenocortical carcinoma. Am J Med 1963; 35: 374
5. Søreide JA, Braband K, Thoresen SØ. Adrenal cortical carcinoma in Norway, 1970-1984. World J Surg 1992; 16: 663 -8
6. Li FP, Frauemeni JF. Soft-tissue sarcomas, breast cancer, and other neoplasms: A familial syndrome? Ann Int Med 1969; 71: 747-52
7. Malkin D, Jolly KW, Barbier N, Look AT, Friend SH, Gebhardt MC, Anderson TI, Boerrson A-L, Li FP, Garber J, Strong LC. Germline mutations of the p53 tumor suppressor gene in children and young adults with second malignant neoplasms. N Engl J Med 1992; 326: 1309- 15
8. Srivastava S, Zou Z, Pirollo K, Blattner W, Chang EH. Germ-line transmission of a mutated p53 gene in a cancer-prone family with Li-Fraumeni syndrome. Nature 1990; 348: 747 - 9
9. Malkin D, Li FP, Strong LC, et al. Germ line p53 mutations in a familial syndrome of breast cancer, sarcomas, and other neo- plasms. Science 1990; 250: 1233-8
10. Hollstein M, Sidransky D, Vogelstein B, Harris CC. p53 muta- tions in human cancers. Science 1991; 253: 49-54
11. Grayson GH, Moore S, Schneider BG, Saldivar V, Hensel CH. No- vel germline mutation of the p53 tumor suppressor gene in a child with incidentally discovered adrenal cortical carcinoma. Am J Pediatr Hematol Oncol 1994; 16: 341 - 7
12. Wagner J, Portwine C, Rabin K, Leclerc JM, Narod SA, Malkin D. High frequency of germline p53 mutations in childhood adre- nocortical cancer. J Natl Cancer Inst 1994; 86: 1707- 10
13. Wiedemann HR. Complex malformatif familial avec hernie om- bilicale et macroglossie - un syndrome nouveau? J Genet Hum 1964; 13: 223-32
14. Beekwith JB. Macroglossia, omphalocoele, adrenal cytomegaly, gigantism and hyperplastic visceromegalie. Birth Defects 1969; 5: 188-96
15. Koufos A, Grundy P, Morgan K, Aleck KA, Hadreos T, Lampkin BC, Kalbakji A, Cavenee WK. Familial Wiedemann-Beckwith syn- drome and a second Wilms tumor locus both map to 11 p15.5. Am J Genet 1989; 44: 711 -9
16. Henry I, Bonaiti-Pellie C, Chehensse V, Beldjord C, Schwartz C, Utermann G, Junien C. Uniparental paternal disomy in a genetic cancer-predisposing syndrome. Nature 1991; 351: 667-70
17. Gicquel C, Xavier B, Schneid H, Francillard-Leblond M, Luton ]-P, Girard F, Le Bouc Y. Rearrangement at the 11 p15 locus and over- expression of IGF-II gene in sporadic adrenocortical tumors. J Clin Endocrinol Metab 1994; 78: 1444-53
18. Chandrasekharrapa SC, Guru SC, Manickam P, Olufemi SE, et al. Positional cloning of the gene for multiple endocrine neoplasia type 1. Science 1997; 276: 404-7
19. Larson C, Scogseid B, Öberg K, Nakamura Y, Nordenskjöld M. MEN type 1 gene maps to chromosome 11 and is lost in insuli- noma. Nature 1988; 332: 85 - 7
20. Skogseid B, Larsson C, Lindgren P-G, Kvanta E, Rastad J, Theo- dorsson E, Wide L, Wilander E, Öberg K. Clinical and genetic fea- tures of adrenocortical lesions in MEN type 1. J Clin Endocrinol Metab 1992; 75: 76-81
21. Sutherland DJ, Ruse JL, Laidlaw JC. Hypertension, increased al- dosterone secretion and low plasma renin activity relieved by dexamethasone. Canad Med Assoc J 1966; 95: 1109- 19
22. Lifton RP, Dluhy RG, Powers M, Rich GM, Cook S, Ulick S, Lalouel JM. A chimeric 11 ß-hydroxylase/aldosterone synthase gene causes glucocorticoid-remidiable aldosteronism and human hypertension. Nature 1992; 355: 262 - 5
23. Pascoe L, Jeunemaitre X, Lebrethon MC, Cumow KM, Gomez- Sanchez CE, Gasc JM, Saez JM, Corvol P. Glucocorticoid-suppres- sible hyperaldosteronism and adrenal tumors occuring in a sin- gle French pedigree. J Clin Invest 1995; 96: 2236-46
24. Stowasser M, Gordon RD, Tunny TJ, Klemm SA, Finn WL, Krek AL. Familial hyperaldosteronism type II: Five families with a new variety of primary aldosteronism. Clin Experim Pharmacol Physiol 1992; 19: 319-22
25. Stratakis CA, Carney JA, Lin J-P, et al. Carney complex: A familial multiple neoplasia and lentiginosis syndrome: Analysis of 11 kindred and linkage to the short arm of chromosome 2. J Clin In- vest 1996; 97: 599 - 607
26. Schteingart DE, Tsao HS. Coexistence of pituitary ACTH-depen- dent Cushing’s syndrome with a solitary adrenal adenoma. J Clin Endocrinol Metab 1980; 50: 961 - 6
27. Hermus AR, Pieters GF, Smals AG, Pesman GJ, Lamberts SW, Benraad TJ, van Haelst UJ, Kloppenborg PW. Transition from pi- tuitary-dependent to adrenal-dependent Cushing’s syndrome. New Engl J Med 1988; 318: 966-70
28. Jaresch S, Schlaghecke R, Jungblut R, Krüskemper HL, Kley HK. Stumme Nebennierentumoren bei Patienten mit adrenogenita- lem Syndrom. Klin Wochenschr 1987; 65: 627 - 33
29. Jaresch S, Kornley E, Kley HK, Schlaghecke R. Adrenal incidenta- loma and patients with homozygous and heterozygous congen- ital adrenal hyperplasia. J Clin Endocrinol Metab 1992; 74: 658-69
30. Reincke M, Allolio B. Molekularbiologie der zufällig diagnosti- zierten Nebennierenraumforderung. Zentralbl Chir 1997; 122: 430-7
31. Schulze E, Maser-Gluth C, Allolio B, Bornstein S, Reineke M. Ste- roid hormone levels and 21-hydroxylase mutations in patients with adrenal incidentalomas. 79 th Annual Meeting of the En- docrine Society, Minneapolis, USA. Program and Abstracts, 1997; P2-87, 306
32. Fialkow PJ. Clonal origin of human tumors. Biochim Biophys Acta 1976; 458: 283- 321
33. Knudson AG. Mutation and human cancer. Adv Cancer Res 1993; 17: 317-52
34. Gicquel C, Leblond-Francillard M, Bertagna X, Louvel A, Chapuls Y, Luton J-P, Girard F, Le Bouc Y. Clonal analysis of human adre- nocortical carcinomas and secreting adenomas. Clin Endocrinol 1994; 40: 465 - 77
35. Beuschlein F, Reineke M, Karl M, Travis W, Jaursch-Hancke C, Abdelhamid S, Chrousos GP, Allolio B. Clonal composition of hu- man adrenocortical neoplasms. Cancer Res 1994; 54: 4927- 32
36. Rico AF, Shao XJ, Gawlitza M, Hensen J. Analysis of clonality in frozen and paraffin-embeded adrenocortical neoplasms by PCR-amplification of short tandem repeats of the human andro- gen receptor gene. Exp Clin Endocrinol Diab 1997; 105 (Suppl. 1): 14-5
37. Gicquel C, Bertagna B, Le Bouc Y. Recent advances in the patho- genesis of adrenocortical tumors. Eur J Endocrinol 1995; 133: 133-44
38. Yano T, Linehan M, Anglard P, Lerman MI, Daniel LN, Stein CA, Robertson N, LaRocca R, Zbar B. Genetic changes in human adre- nocortical carcinoma. J Natl Cancer Inst 1989; 81: 518-23
39. Limon J, Dal Cin P, Gaeat J, Sandberg A. Translocation t(4;11) (q35; p13) in an adrenocortical carcinoma. Cancer Genet Cyto- genet 1987; 28: 343 - 8
40. Herrmann M, Rydstedt L, Talpos G, Ratner S, Wollman S, Lalley P. Chromosomal aberrations in two adrenocortical tumors, one with rearrangement at 11 p15. Cancer Genet Cytogenet 1994; 75: 111-6
41. Gordon RD, Stowasser M, Martin N, Epping A, Conic S, Klemm SA, Tunny TJ, Rutherford JC. Karyotypic abnormalities in benign adrenocortical tumors producing aldosterone. Cancer Genet Cy- togenet 1993; 68: 78-81
42. Rosenberg C, Della-Rosa VA, Latronico AC, Mendoca BB, Vianna- Morgante AM. Selection of adrenal tumor cells in culture dem- onstrated by interphase cytogenetics. Cancer Genet Cytogenet 1994; 79: 36-40
43. Kjellman M, Kallioniemi OP, Karhu R, Höög A, Farnebo LO, Auer G, Larsson C, Bäckdahl M. Genetic abberations in adrenocortical tumors detected using comparative genomic hybridization cor- relate with tumor size and malignancy. Cancer Res 1996; 56: 4219-23
44. Reincke M, Dohna M, Solinas-Toldo S, Allolio B, Lichter P. Multi- ple chromosomal aberrations in benign and malignant adreno- cortical tumors using comparative genomic hybridization. 79 th Annual Meeting of The Endocrine Society, Minneapolis, USA. Program and Abstracts, 1997; P2 - 108, 311
45. Lyons J, Landis CA, Harsh G, Vallar L, Grünewald K, Feichtinger H, Duh QY, Clark OH, Kawasaki E, Bourne HR, McCormick F. Two G protein oncogenes in human endocrine tumors. Science 1990; 249: 655 - 9
46. Parma J, Duprez L, Van Sande J, Cochaux P, Gervy C, Mockel J, Dumont J, Vasart G. Somatic mutations in the thyrotropin re- ceptor gene cause hyperfunctioning thyroid adenomas. Nature 1993; 365: 649-51
47. Estivariz FE, Iturriza F, Mclean C, Hope J, Lowry PJ. Stimulation of adrenal mitogenesis by N-terminal proopiomelanocortin. Nature 1982; 297: 419-22
48. Latronico AC, Reincke M, Mendonca BB, et al. No evidence for oncogenic mutations in the adrenocorticotropin receptor gene in human adrenocortical neoplasms. J Clin Endocrinol Metab 1995; 80: 875-7
49. Light K, Jenkins PJ, Weber A, Perrett C, Grossman A, Pistorello M, Asa SL, Clayton RN, Clark AJL. Are activating mutations of the ACTH receptor involved in adrenal cortical neoplasia? Life Sci 1995; 56: 1523-7
50. Reincke M, Karl M, Travis W, Chrousos GP. No evidence for onco- genic mutations in guanine nucleotide binding proteins of hu- man adrenocortical neoplasms. J Clin Endocrinol Metab 1993; 77: 1419-22
51. Gicquel C, Dib A, Bertagna X, Amselem S, Le Bouc Y. Oncogenic mutations of alpha-Gi2 are not determinant for human adreno- cortical tumorigenesis. Eur J Endocrinol 1995; 133: 166-72
52. Reincke M, Mora P, Beuschlein F, Arlt W, Chrousos GP, Allolio B. Deletion of the ACTH receptor gene in adrenocortical tumors: Implication for tumorigenesis. J Clin Endocrinol Metab 1997; 82: 3054-8
53. Sachse R, Shao X-J, Rico A, Finckh U, Rolfs A, Reincke M, Hensen J. Absence of angiotensin II type 1 receptor gene mutations in human adrenal tumors. Eur J Endocrinol, submitted
54. Latronieo AC, Mendonca BB, Bianco AC, Villares SM, Lucon MA, Nicolau W, Wajchenberg BL. Calcium-dependent protein kinase-C activity in human adrenocortical neoplasms, hyper- plastic adrenals, and normal adrenal tissue. J Clin Endocrinol Metab 1994; 79: 736-9
55. Moul JW, Bishoff JT, Theune SM, Chang EH. Absent ras gene mu- tations in human adrenal cortical neoplasms and pheochromo- cytomas. J Urology 1993; 149: 1389-94
56. Ohgaki H, Kleihues P, Heitz PU. p53 mutations in sporadic adre- nocortical tumors. Int J Cancer 1993; 54: 408 - 10
57. Yashiro T, Hara H, Obara T, Kaplan EL. Point mutation of ras in human adrenal cortical tumor: Absence in adrenocortical hy- perplasia. World J Surg 1994; 18: 455-60
58. Gicquel C, Raffin-Sanson ML, Gaston V, Bertagna X, Plouin PF, Schlumberger M, Louvel A, Luton JP, Le Bouc Y. Structural and functional abnormalities at 11 p15 are associated with the ma- lignant phenotype in sporadic adrenocortical tumors: Study on a series of 82 tumors. J Clin Endocrinol Metab 1997; 82: 2559 - 65
59. Ilvesmäki V, Kahri AI, Miettinen PJ, Voutilainen R. Insulin-like growth factors and their receptors in adrenal tumors: High IGF II expression in functional adrenocortical carcinomas. J Clin En- docrinol Metab 1993; 77: 852
60. Lin SR, Lee YJ, Tsai JH. Mutations of the p53 gene in human func- tional neoplasms. J Clin Endocrinol Metab 1994; 78: 483-91
61. Reincke M, Wachenfeld C, Mora P, Thumser A, Jaursch-Hancke C, Abdelhamid S, Chrousos GP, Allolio B. p53 mutations in adre- nal tumors: Caucasian patients do not show the exon 4 “hot spot” found in Taiwan. J Clin Endocrinol Metab 1996; 81: 3636-8
62. Reincke M, Karl M, Travis WH, Mastorakos G, Allolio B, Linehan HM, Chrousos GP. p53 mutations in human adrenocortical neo- plasms: Immunohistochemical and molecular studies. J Clin Endocrinol Metab 1994; 78: 790-4
63. Liu J, Kahri Al, Heikkila P, Voutilainen R. Ribonucleic acid ex- pression of the clustered imprinted genes, p57KIP2, IGF-II, and H19, in adrenal tumors and cultered adrenal cells. J Clin Endo- crinol Metab 1997; 82: 1766-71
64. Kamio T, Shigematsu K, Kawai K, Tsuchiyama H. Immunoreac- tivity and receptor expression of IGF-I and insulin in human adrenal tumors. Am J Pathol 1991; 138: 83-91
65. Levine AJ, Momand J, Finlay CA. The p53 tumour suppressor gene. Nature 1991; 351: 453 - 6
66. Esrig D, Elmajian D, Cote RJ. Accumulation of nuclear p53 and tumor progression in bladder cancer. N Engl J Med 1994; 331: 1259-64
67. Baker SJ, Preisinger AC, Jessup JM, Paraskeva C, Markowitz S, Willson JKV, Hamilton S, Vogelstein B. p53 gene mutations oc- cur in combination with 17 p allelic deletions as late events in colorectal tumorigenesis. Cancer Res. 1990; 50: 7717 - 22
68. Caron de Fromentel C, Soussi T. p53 tumor suppressor gene: A model for investigating human mutagenesis. Genes Chrom Can- cer 1992; 4: 1 - 15
69. Hartmann A, Blaszyk H, Sommer SS. p53 gene mutations inside and outside of exons 5-8: The patterns differ in breast and other cancers. Oncogene 1995; 10: 681 - 8
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