Targeted Mutational Analysis of Cortisol-Producing Adenomas

Abstract

Background Somatic gene mutations have been identified in only about half of cortisol-producing adenomas (CPA). Affected genes include PRKACA, GNAS, PRKAR1A, and CTNNB1. Objective To expand our understanding of the prevalence of somatic mutations in CPA from patients with overt Cushing syndrome (OCS) and “subclinical” mild autonomous cortisol excess (MACE), with an immunohistochemistry (IHC)‒guided targeted amplicon sequencing approach using formalin-fixed paraffin-embedded (FFPE) tissue. Method We analyzed FFPE adrenal tissue from 77 patients (n=12 men, 65 women) with either OCS (n=32) or MACE (n=45). Using IHC for 17α-hydroxylase/17,20-lyase (CYP17A1) and 3β-hydroxysteroid dehydrogenase (HSD3B2), we identified 78 CPA (32 OCS-CPA and 46 MACE-CPA). Genomic DNA was isolated from the FFPE CPA and subjected to targeted amplicon sequencing for identification of somatic mutations. Results Somatic mutations were identified in 71.8% (56/78) of the CPA. While PRKACA was the most frequently mutated gene in OCS-CPA (14/32, 43.8%), somatic genetic aberrations in CTNNB1 occurred in 56.5% (26/46) of the MACE-CPA. Most GNAS mutations were observed in MACE-CPA (5/7,71.4%). No mutations were observed in PRKAR1A. In addition to the known mutations, we identified one previously unreported mutation in PRKACA. Two patients with MACE harbored two adjacent tumors within the same adrenal gland: one patient had two CPA, and the other patient had a CPA and an aldosterone-producing adenoma (identified by IHC for aldosterone synthase). Conclusion Comprehensive FFPE IHC-guided gene-targeted sequencing approach identified somatic mutations in 71.8% of the CPA. OCS-CPA demonstrated a distinct mutation profile compared to MACE-CPA.

Cell Atlas at Single-Nuclei Resolution of the Adult Human Adrenal Gland and Adrenocortical Adenomas

“…In a first step, we interrogated benign adrenocortical tumours (adenomas), which were further classified according to glucocorticoid secretion and mutational status. Using this approach, a high intratumoural heterogeneity was observed, confirming for the first time at single-nuclei level previous morphological and genetic findings in bulk tumours [57][58][59] .…”

Increased copy number of imprinted genes in the chromosomal region 20q11-q13.32 is associated with resistance to antitumor agents in cancer cell lines

“…Genetic variation in GNAS is associated with birth weight [11,148]. Mutations in the GNAS gene are frequently observed in a variety of malignant, premalignant, and benign tumors and in tumor-derived organoids and patient-derived xenografts [19,[149][150][151][152][153][154]. This gene has been reported to play an oncogenic role in SCLC.…”

“…Tissue specificity of their imprinting, in addition to variation in gene expression among tissues regulated by mechanisms other than imprinting, underscores the importance of future analyses of associations of allelic dosage, parent-specific allelic expression, and novel types of omics data [3] with drug response, which would need to be conducted in separate tumor categories with large sample sizes. An additional analysis of the mutation status of the imprinted genes in tumors would add further depth to the understanding of their influence on drug response, since protein-changing mutations in many imprinted genes including those genes which were associated with drug response in our study, e.g., NLRP2, CDKN1C, and GNAS, commonly occur in patients with imprinted disorders and/or cancer [1,129,131,[149][150][151][152][153][154]156].…”

Primary aldosteronism: Pathophysiological mechanisms of cell death and proliferation

“…GNAS mutations frequently alter either a p.Arg201 or a p.Gln227 residue, which are required for GTPase activity. GNAS mutations are found in a substantial proportion of cortisol-producing adenomas associated with subclinical mild autonomous cortisol excess (5 of 7, 71.4%) ( 54 ). Only a few APA with GNAS mutations (GNAS p.Arg201Cys) have been described and these were in cases of PA associated with autonomous cortisol secretion and activation of cAMP/PKA (protein kinase A) signaling ( 19 ).…”

“…The rare examples of APA GNAS mutations are discussed above (under G protein signaling). Somatic PRKACA mutations, encoding a p.Leu206Arg substitution in the catalytic PKA subunit, have been identified in a substantial proportion of cortisol-producing adenomas ( 54 , 60 , 62 , 63 ). PRKACA Leu206 directly interacts with the PKA regulatory subunit.…”