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Insulin-like growth factor 2 (IGF2) overexpression is an important molecular marker of adrenocortical carcinoma (ACC), which is a rare but devastating endocrine cancer. It is not clear whether IGF2 overexpression modifies the biology and growth of this cancer, thus more studies are required before IGF2 can be considered as a major therapeutic target. We compared the phenotypical, clinical, biological, and molecular characteristics of ACC with or without the overexpression of IGF2, to address these issues. We also carried out a similar analysis in an ACC cell line (H295R) in which IGF2 expression was knocked down with si- or shRNA. We found no significant differences in the clinical, biological and molecular (transcriptomic) traits between IGF2-high and IGF2-low ACC. The absence of IGF2 overexpression had little influence on the activation of tyrosine kinase pathways both in tumors and in H295 cells that express low levels of IGF2. In IGF2-low tumors, other growth factors (FGF9, PDGFA) are more expressed than in IGF2-high tumors, suggesting that they play a compensatory role in tumor progression. In addition, IGF2 knock-down in H295R cells substantially impaired growth (>50% inhibition), blocked cells in G1 phase, and promoted apoptosis (>2-fold). Finally, analysis of the 11p15 locus showed a paternal uniparental disomy in both IGF2-high and IGF2-low tumors, but low IGF2 expression could be explained in most IGF2-low ACC by an additional epigenetic modification at the 11p15 locus. Altogether, these observations confirm the active role of IGF2 in adrenocortical tumor growth, but also suggest that other growth promoting pathways may be involved in a subset of ACC with low IGF2 expression, which creates opportunities for the use of other targeted therapies.

Adrenocortical carcinomas (ACCs) are aggressive cancers originating in the cortex of the adrenal gland. Despite overall poor prognosis, ACC outcome is heterogeneous. We performed exome sequencing and SNP array analysis of 45 ACCs and identified recurrent alterations in known driver genes (CTNNB1, TP53, CDKN2A, RB1 and MEN1) and in genes not previously reported in ACC (ZNRF3, DAXX, TERT and MED12), which we validated in an independent cohort of 77 ACCs. ZNRF3, encoding a cell surface E3 ubiquitin ligase, was the most frequently altered gene (21%) and is a potential new tumor suppressor gene related to the β-catenin pathway. Our integrated genomic analyses further identified two distinct molecular subgroups with opposite outcome. The C1A group of ACCs with poor outcome displayed numerous mutations and DNA methylation alterations, whereas the C1B group of ACCs with good prognosis displayed specific deregulation of two microRNA clusters. Thus, aggressive and indolent ACCs correspond to two distinct molecular entities driven by different oncogenic alterations.

Context: Adrenocortical carcinoma (ACC) is a rare disease with a poor overall outcome. Transcriptome analysis identified two groups of ACCs with different prognosis. In aggressive ACCs, somatic mutations of the tumor suppressor gene TP53 and the proto-oncogene β-catenin are detected in 50% of cases. For the remaining aggressive ACCs and for the group with a better prognosis, molecular alterations are unknown., Objective: To identify new molecular actors driving adrenal tumorigenesis., Experimental Design: Analysis by mass array of 374 mutations among 32 common oncogenes or tumor suppressor genes was performed on the tumoral DNA of 26 ACCs, using Sequenom OncoCarta Panels., Results: Four mutations were identified, two previously known β-catenin mutations and one alteration in two other genes: JAK3 and retinoblastoma gene (RB1). The JAK3 alteration was found in leukocyte DNA and therefore considered as a polymorphism and not a somatic event. The full RB1 tumor suppressor gene was subsequently sequenced in a cohort of 49 ACCs (26 ACCs from the 'OncoCarta cohort' and 23 other ACCs): three somatic mutations were identified, all in the poor-outcome ACC group. By immunohistochemistry, a loss of the retinoblastoma protein (pRb) was found exclusively in aggressive ACCs in 27% of cases (seven out of 26), three of them with an inactivating RB1 mutation. Among the seven pRb-negative ACCs, five had an allele loss at the RB1 locus., Conclusions: Parallel analysis of somatic mutations among known cancer genes allowed us to identify RB1 as a new actor in aggressive ACCs. These results suggest a prognostic significance of pRb expression loss in ACCs.

Background: Corticotropin-independent macronodular adrenal hyperplasia may be an incidental finding or it may be identified during evaluation for Cushing's syndrome. Reports of familial cases and the involvement of both adrenal glands suggest a genetic origin of this condition., Methods: We genotyped blood and tumor DNA obtained from 33 patients with corticotropin-independent macronodular adrenal hyperplasia (12 men and 21 women who were 30 to 73 years of age), using single-nucleotide polymorphism arrays, microsatellite markers, and whole-genome and Sanger sequencing. The effects of armadillo repeat containing 5 (ARMC5) inactivation and overexpression were tested in cell-culture models., Results: The most frequent somatic chromosome alteration was loss of heterozygosity at 16p (in 8 of 33 patients for whom data were available [24%]). The most frequent mutation identified by means of whole-genome sequencing was in ARMC5, located at 16p11.2. ARMC5 mutations were detected in tumors obtained from 18 of 33 patients (55%). In all cases, both alleles of ARMC5 carried mutations: one germline and the other somatic. In 4 patients with a germline ARMC5 mutation, different nodules from the affected adrenals harbored different secondary ARMC5 alterations. Transcriptome-based classification of corticotropin-independent macronodular adrenal hyperplasia indicated that ARMC5 mutations influenced gene expression, since all cases with mutations clustered together. ARMC5 inactivation decreased steroidogenesis in vitro, and its overexpression altered cell survival., Conclusions: Some cases of corticotropin-independent macronodular adrenal hyperplasia appear to be genetic, most often with inactivating mutations of ARMC5, a putative tumor-suppressor gene. Genetic testing for this condition, which often has a long and insidious prediagnostic course, might result in earlier identification and better management. (Funded by Agence Nationale de la Recherche and others.).

Context: The cortisol secretion of adrenocortical adenomas can be either subtle or overt. The mechanisms leading to the autonomous hypersecretion of cortisol are unknown., Objective: The objective of the study was to identify the gene expression profile associated with the autonomous and excessive cortisol secretion of adrenocortical adenomas., Patients and Methods: The transcriptome of 22 unilateral adrenocortical adenomas (5 nonsecreting, 6 subclinical cortisol producing, 11 cortisol producing) was studied and correlated with cortisol secretion. Phosphodiesterase 8B (PDE8B) expression was measured by Western blot., Results: Unsupervised clustering identified 2 groups of adenomas with a difference in secretion level (P = .008). Cluster 1 included only cortisol-producing adenomas (8 of 11), whereas cluster 2 was an admixture of the nonsecreting, the subclinical cortisol-secreting, and 3 of the 11 cortisol-secreting adenomas (Fisher exact, P = .002). This cluster was driven by genes related to cortisol secretion and to extracellular matrix. More than 3000 genes correlated with cortisol secretion. Among the positively correlated were the steroidogenic enzymes, genes involved in cholesterol metabolism, and glutathione S-transferases. Among the negatively correlated genes were genes related to transcripts translation and the transcription factor GATA-6. The PDE8B, which inactivates the protein kinase A pathway, unexpectedly showed the strongest positive correlation with cortisol secretion, confirmed by Western blot. The protein kinase A-activity to cAMP ratio was increased in adenomas with high PDE8B levels, suggesting counterregulation to limit downstream activation of the pathway., Conclusion: The transcriptome of adrenocortical adenomas reveals a major association with cortisol secretion and identifies specific groups of genes implicated in steroid secretion, suggesting that cAMP signaling alterations might be frequent in cortisol-secreting adenomas.

Purpose: DNA methylation is a mechanism for gene expression silencing in cancer. Limited information is available for adrenocortical tumors. Abnormal methylation at the IGF2/H19 locus is common in adrenocortical carcinomas. Our aim was to characterize the methylation in adrenocortical carcinomas at a whole-genome scale and to assess its clinical significance and its impact on gene expression., Experimental Design: Methylation patterns of CpG islands in promoter regions of 51 adrenocortical carcinomas and 84 adenomas were studied by the Infinium HumanMethylation27 Beadchip (Illumina, San Diego, CA). Methylation of 33 genes was studied by methylation-specific multiplex ligation-dependent probe amplification (MRC-Holland, Amsterdam, The Netherlands) in 15 carcinomas. Gene expression data were available for 87 tumors from a previous study (HG-U133Plus2.0 AffymetrixGeneChip; Affymetrix, Santa Clara, CA). Clinical information, including patient features and survival, were available for all tumors., Results: Methylation was higher in carcinomas than in adenomas (t test P = 3.1 × 10(-9)). Unsupervised clustering of DNA methylation profiles identified two groups of carcinomas, one with an elevated methylation level, evoking a CpG island methylator phenotype (CIMP). The subgroup of hypermethylated carcinomas was further divided in two subgroups, with different levels of methylation (CIMP-high and CIMP-low). This classification could be confirmed by methylation-specific multiplex ligation-dependent probe amplification. Hypermethylation was associated with a poor survival (Cox model P = 0.02). The transcriptome/methylation correlation showed 1741 genes (of 12,250) negatively correlated; among the top genes were H19 and other tumor suppressors (PLAGL-1, G0S2, and NDRG2)., Conclusions: This genome-wide methylation analysis reveals the existence of hypermethylated adrenocortical carcinomas, with a poorer prognosis. Hypermethylation in these tumors is important for silencing specific tumor suppressor genes.

Context: Phosphodiesterases (PDEs) are key regulatory enzymes of intracellular cAMP levels. PDE11A function has been linked to predisposition to adrenocortical tumors., Objective: The aim of the study was to study the PDE11A gene in a large cohort of patients with ACTH-independent macronodular adrenal hyperplasia (AIMAH) and in control subjects., Design: The PDE11A entire coding region was sequenced in 46 patients with AIMAH and 192 controls. Two variants found in AIMAH patients were transiently expressed in HEK 293 and adrenocortical H295R cells for further functional studies., Results: The frequency of all PDE11A variants was significantly higher among patients with AIMAH (28%) compared to controls (7.2%) (P = 5 × 10(-5)). Transfection of the two PDE11A variants found in AIMAH patients only (D609N or M878V) showed that cAMP levels were higher, after forskolin stimulation, in cells transfected with the PDE11A mutants, compared to cells transfected with the wild-type PDE11A in HEK 293 cells (P < 0.05). Moreover, transfection with mutants PDE11A increased transcriptional activity of a cAMP-response element reporter construct compared to wild-type PDE11A in HEK 293 cells (P < 0.0004 for D609N and P < 0.003 for M878V) and in the adrenocortical H295R cells (P < 0.05 for D609N and M878V). In addition, analysis of cAMP levels in intact living culture cells by fluorescence resonance energy transfer probes showed increased cAMP in forskolin-treated cells transfected with PDE11A variants compared with wild-type PDE11A (P < 0.05)., Conclusion: We conclude that PDE11A genetic variants may increase predisposition to AIMAH.

Purpose: Diagnosing malignancy of adrenocortical tumors (ACT) and predicting prognosis in carcinomas are often challenging. Transcriptome markers have recently emerged, providing promising clinical relevance and improved pathophysiological knowledge. Whether tumoral chromosomal alterations provide similar information is not known. The aim was to evaluate the diagnostic and prognostic value of chromosomal alterations in ACT and to identify genes associated with benign and malignant tumorigenesis., Experimental Design: Chromosomal alterations of 86 adenomas and 52 carcinomas were identified by comparative genomic hybridization arrays and/or quantitative PCR., Results: A larger proportion of the genome is altered in carcinomas compared with adenomas (44 vs. 10%, P = 2.10(-10)). In adenomas, the 9q34 region, which includes the steroidogenic factor 1 locus, is commonly gained and associated with an overexpression of steroidogenic factor 1 (SF-1). In carcinomas, recurrent gains include chromosomes 5, 7, 12, 16, 19, and 20 and recurrent losses chromosomes 13 and 22. Filtering the genes from these regions according to their expression profile identified genes potentially relevant to adrenocortical tumorigenesis. A diagnostic tool was built by combining DNA copy number estimates at six loci (5q, 7p, 11p, 13q, 16q, and 22q). This tool discriminates carcinomas from adenomas in an independent validation cohort (sensitivity 100%, specificity 83%). In carcinomas, the number of chromosomal alterations was not associated with survival (Cox P = 0.84). A prognostic tool based on tumor DNA was designed with a clustering strategy and validated in an independent cohort., Conclusions: Chromosomal alterations in ACT discriminate carcinomas from adenomas and contain prognostic information. Chromosomal alterations alter the expression of genes important for tumorigenesis.

Background: Abnormal β-catenin immunohistochemistry and mutations of the β-catenin gene (CTNNB1) have been reported in adrenocortical adenomas (ACAs), but the frequencies of these defects and the phenotype of such tumors have not been clearly determined., Objective: The objective of the study was to describe the Wnt/β-catenin pathway alterations in 100 ACAs and their association with clinicopathological characteristics., Patients and Methods: One hundred consecutive ACAs (excluding Conn's adenomas) were studied clinically by β-catenin immunohistochemistry and direct sequencing of CTNNB1., Results: Thirty-five ACAs were nonsecreting adenomas (NSAs), 19 were subclinical cortisol secreting adenomas (SCSAs), and 46 were cortisol secreting adenomas (CSAs). Fifty-one tumors had abnormal cytoplasmic and/or nuclear β-catenin immunohistochemical staining, indicating Wnt/β-catenin pathway alteration. Thirty-six tumors showed CTNNB1 mutations, which all showed abnormal immunohistochemical β-catenin accumulation. Among the 64 nonmutated tumors, only 15 (23%) showed cytoplasmic and/or nuclear β-catenin staining (P < 0.0001). Tumors with CTNNB1 mutations were predominantly nonsecreting (61% NSAs, 22% SCSAs, 16% CSAs) whereas nonmutated tumors were predominantly secreting (20% NSAs, 17% SCSAs, 62% CSAs) (P < 0.0001). Mean tumor size and weight were, respectively, 4.2 cm (± 1.3) and 28.4 g (± 21.4) for tumors with CTNNB1 mutations vs. 3.4 cm (± 0.9) and 18.2 g (± 8.2) for nonmutated tumors (P < 0.01)., Conclusions: Abnormal cytoplasmic and/or nuclear β-catenin immunohistochemical staining occurs in about half of ACAs. This suggests the activation of the Wnt/β-catenin pathway, which could be explained by activating mutations of CTNNB1 in 70% of the cases. CTNNB1 mutations are mainly observed in larger and nonsecreting ACAs, suggesting that the Wnt/β-catenin pathway activation is associated with the development of less differentiated ACAs.

Context: Stimulation of cortisol secretion through abnormally expressed G protein-coupled receptors (GPCRs) is a frequent feature of ACTH-independent macronodular adrenal hyperplasia (AIMAH). This has opened a pharmacological strategy that targets GPCRs for the treatment of Cushing's syndrome in AIMAH. However, only few drugs are available for the presently described GPCRs., Objective: The objective of the study was to identify new GPCR targets for the pharmacological treatment of adrenal Cushing's syndrome., Design and Patients: We designed a cDNA chip containing 865 nucleotidic sequences of GPCRs. mRNAs were extracted from three normal adrenals, 18 AIMAHs, four adrenals from Cushing's disease patients, and 13 cortisol-secreting adenomas. A set of GPCR mRNAs that showed significantly higher or lower expression in AIMAH than in normal adrenal were studied by quantitative RT-PCR analysis. Analysis of protein expression and function were performed on selected GPCRs., Setting: The study was conducted at a tertiary care center and basic research laboratories., Results: The ACTH MC2 receptor showed a low expression in 15 of 18 AIMAHs samples, whereas several previously undescribed GPCR genes were found highly expressed in a subset of AIMAH, such as the receptors for motilin (MLNR; three of 18 AIMAHs) and γ-aminobutyric acid (GABBR1; five of 18 AIMAHs), and the α2A adrenergic receptor (ADRA2A; 13 of 18 AIMAHs), on which we focused our attention. Western blot and immunochemistry analyses showed expression of ADRA2A protein in AIMAH but not in normal adrenal cortex. The ADRA2A agonist clonidine enhanced both basal and stimulated cortisol production. Clonidine-induced increase in basal cortisol levels was blocked by the ADRA2A antagonist yohimbine., Conclusion: ADRA2A is a potential target for pharmacological treatment of Cushing's syndrome linked to AIMAH.

PRKAR1A encodes the regulatory subunit type 1-alpha (RIalpha) of the cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA). Inactivating PRKAR1A mutations are known to be responsible for the multiple neoplasia and lentiginosis syndrome Carney complex (CNC). To date, at least 117 pathogenic variants in PRKAR1A have been identified (online database: http://prkar1a.nichd.nih.gov). The majority are subject to nonsense mediated mRNA decay (NMD), leading to RIalpha haploinsufficiency and, as a result, activated cAMP signaling. Recently, it became apparent that CNC may be caused not only by RIalpha haploinsufficiency, but also by the expression of altered RIalpha protein, as proven by analysis of expressed mutations in the gene, consisting of amino acid substitutions and in-frame genetic alterations. In addition, a new subgroup of mutations that potentially escape NMD and result in CNC through altered (rather than missing) protein has been analyzed-these are frame-shifts in the 3' end of the coding sequence that shift the stop codon downstream of the normal one. The mutation detection rate in CNC patients is recently estimated at above 60%; PRKAR1A mutation-negative CNC patients are characterized by significant phenotypic heterogeneity. In this report, we present a comprehensive analysis of all presently known PRKAR1A sequence variations and discuss their molecular context and clinical phenotype., (Published 2010 Wiley-Liss, Inc.)

Background: The "complex of myxomas, spotty skin pigmentation, and endocrine overactivity," or "Carney complex" (CNC), is caused by inactivating mutations of the regulatory subunit type 1A of the cAMP-dependent protein kinase (PRKAR1A) gene and as yet unknown defect(s) in other gene(s). Delineation of a genotype-phenotype correlation for CNC patients is essential for understanding PRKAR1A function and providing counseling and preventive care., Methods: A transatlantic consortium studied the molecular genotype and clinical phenotype of 353 patients (221 females and 132 males, age 34 +/- 19 yr) who carried a germline PRKAR1A mutation or were diagnosed with CNC and/or primary pigmented nodular adrenocortical disease., Results: A total of 258 patients (73%) carried 80 different PRKAR1A mutations; 114 (62%) of the index cases had a PRKAR1A mutation. Most PRKAR1A mutations (82%) led to lack of detectable mutant protein (nonexpressed mutations) because of nonsense mRNA mediated decay. Patients with a PRKAR1A mutation were more likely to have pigmented skin lesions, myxomas, and thyroid and gonadal tumors; they also presented earlier with these tumors. Primary pigmented nodular adrenocortical disease occurred earlier, was more frequent in females, and was the only manifestation of CNC with a gender predilection. Mutations located in exons were more often associated with acromegaly, myxomas, lentigines, and schwannomas, whereas the frequent c.491-492delTG mutation was commonly associated with lentigines, cardiac myxomas, and thyroid tumors. Overall, nonexpressed PRKAR1A mutations were associated with less severe disease., Conclusion: CNC is genetically and clinically heterogeneous. Certain tumors are more frequent, with specific mutations providing some genotype-phenotype correlation for PRKAR1A mutations.

Objective: Germline mutations of the aryl hydrocarbon receptor-interacting protein gene (AIP) have recently been described in three families with GH or prolactin-secreting tumors, as well as in a few patients with apparently sporadic somatotropinomas. The aim of the study was to determine the prevalence of AIP mutations in a large cohort of patients with apparently sporadic GH-secreting tumors., Design: One hundred and fifty-four patients were included in a prospective cohort designed to study the genetic predisposition to GH-secreting tumors together with 270 controls., Methods: In all these subjects, the entire coding sequence of the AIP gene was screened for germline mutations., Results: AIP mutations were detected in 5 out of 154 patients (3%): nonsense mutations in exon 4 (p.Lys201X; n = 2) and in exon 6 (p.Arg304X), one deletion in exon 3 (c.404delA; pHis135LeufsX21), and one mutation affecting the splice acceptor site of exon 4 (c.469-2 A > G). The five patients with an AIP mutation were significantly younger (mean age +/- S.D.: 25 +/- 10 vs 43 +/- 14 years, P = 0.005) and three of them presented with gigantism. One missense mutation (p.Arg304Gln) was found in a single patient that was absent in all controls., Conclusions: Germline mutations of the AIP gene were found in a small proportion of patients with sporadic pituitary somatotropinomas. This study shows that age and gigantism are simple clinical features which can help to select patients for mutation screening. It also supports the role of AIP in pituitary tumorigenesis.

Purpose: Allelic losses [loss of heterozygosity (LOH)] at the 17p13 locus are frequent (85%) in adrenocortical cancers. The tumor suppressor gene TP53 is located at 17p13. The aim of the study was to determine the frequency of TP53 somatic inactivating mutations in adrenocortical tumors with 17p13 LOH and their clinico-biological correlations., Experimental Design: TP53 somatic mutations, intragenic LOH (VNTR1 marker), and p53 overexpression were studied in 36 adrenocortical tumors with 17p13 LOH determined by Southern blot., Results: TP53 mutations were detected in 33% of the tumors, and VNTR1 LOH was present in 44% of the cases and did not always correlate with the presence of a TP53 mutation. Only the TP53-mutant tumors exhibit a strong nuclear immunoreactivity. TP53-mutant tumors were significantly larger than wild-type TP53 tumors (median tumor weight: 640 versus 185 g; P=0.02), were associated with a more advanced stage of tumor progression (MacFarlane stage IV; P=0.01), and had a shorter disease-free survival (P=0.03)., Conclusions: The finding that only a minority of adrenocortical tumors with 17p13 LOH had either a VNTR1 LOH or a TP53 mutation indicates that TP53 might not be the only or major tumor suppressor gene at 17p13 involved in adrenocortical cancer progression. We suggest that a genetic instability of the 17p13 region, occurring early in adrenocortical cancer development, involves various genes located in this region. TP53 might be only one of them, and its alteration by the occurrence of inactivating mutation is associated with the development of more aggressive tumors.

Adrenocortical cancer is a rare cancer with a very poor prognosis. The genetic alterations identified to date in adrenocortical tumors are limited. Activating mutations of the Wnt signaling pathway have been observed in more frequent cancers, particularly digestive tract tumors. We investigated whether Wnt pathway activation is involved in adrenocortical tumorigenesis. In a series of 39 adrenocortical tumors, immunohistochemistry revealed abnormal cytoplasmic and/or nuclear accumulation of beta-catenin in 10 of 26 adrenocortical adenomas and in 11 of 13 adrenocortical carcinomas. An activating somatic mutation of the beta-catenin gene was shown in 7 of 26 adrenocortical adenomas and in 4 of 13 adrenocortical carcinomas; these mutations were observed only in adrenocortical tumors with abnormal beta-catenin accumulation and most were point mutations altering the Ser45 of exon 3 (in the consensus GSK3-beta/CK1 phosphorylation site). Functional studies showed that the activating Ser45 beta-catenin mutation found in the adrenocortical cancer H295R cell line leads to constitutive activation of T-cell factor-dependent transcription. This is the first molecular defect to be reported with the same prevalence in both benign (27%) and malignant (31%) adrenocortical tumors. beta-Catenin mutations are also the most frequent genetic defect currently known in adrenocortical adenomas. In adrenocortical adenomas, beta-catenin alterations are more frequent in nonfunctioning tumors, suggesting that beta-catenin pathway activation might be mostly involved in the development of nonsecreting adrenocortical adenomas and adrenocortical carcinomas. The very frequent and substantial accumulation of beta-catenin in adrenocortical carcinomas suggests that other alterations might also be involved. This finding may contribute to new therapeutic approaches targeting the Wnt pathway in malignant adrenocortical tumors, for which limited medical therapy is available.

The Carney complex (CNC) is a dominantly inherited syndrome responsible mainly for spotty skin pigmentation (lentiginosis), endocrine overactivity, and cardiac myxomas. Adrenocorticotropic hormone independent Cushing's syndrome due to primary pigmented nodular adrenocortical disease (PPNAD) is a main characteristic of CNC. PPNAD is a very rare cause of Cushing's syndrome due to a primary bilateral adrenal defect that can be also observed in some patients without other CNC manifestations nor familial history. One of the putative CNC genes, located on 17q22-24, has been identified as the regulatory subunit R1A of protein kinase A (PRKAR1A). Heterozygous inactivating mutations of PRKAR1A have been reported initially in about 45% of the CNC index cases and could be found in about 80% of the CNC families presenting mainly with Cushing's syndrome. PRKAR1A is a key component of the cyclic AMP signaling pathway that has been implicated in endocrine tumorigenesis and could, at least partly, function as a tumor suppressor gene. Interestingly, patients with isolated PPNAD and no familial history of CNC can also present a germline de novo mutation of PRKAR1A. Somatic mutations of PRKAR1A have been found in PPNAD as a mechanism of inactivation of the wild-type allele, in a patient already presenting a germline mutation, and in a subset of sporadic secreting adrenocortical adenomas with clinical, hormonal, and pathological features quite similar to PPNAD. This review will summarize the recent findings on CNC from the perspective of the pathophysiology of adrenal Cushing's syndrome and PPNAD., (Copyright (c) 2005 S. Karger AG, Basel.)