DNA methylation of steroidogenic enzymes in benign adrenocortical tumors: New insights in aldosterone-producing adenomas

Abstract

Context: DNA methylation has been identified among putative regulatory mechanisms for CYP11B2 expression in primary aldosteronism. Objective: The objective of this work is to investigate DNA methylation and expression of genes encoding steroidogenic enzymes in benign adrenocortical tumors. Design and Setting: This cross-sectional study took place at university hospitals. Patients: We collected fresh-frozen tissues from patients with benign adrenocortical adenomas (n = 48) (nonfunctioning n = 9, autonomous cortisol secretion n = 9, Cushing syndrome n = 17, aldosterone-producing [APA] n = 13) and adrenal cortex adjacent to APA (n = 12). We collected formalin-fixed, paraffin-embedded (FFPE) specimens of paired APA and concurrent aldosterone-producing cell clusters (APCCs) (n = 6). Intervention: DNA methylation levels were evaluated by quantitative bisulfite next-generation sequencing in fresh-frozen tissues (CYP11A1, CYP11B1, CYP11B2, CYP17A1, CYP21A2, HSD3B1, HSD3B2, NR5A1, STAR, and TSPO) and FFPE APA/APCC paired samples (CYP11B2). CYP11B1, CYP11B2, CYP17, CYP21, and STAR gene expressions were examined by quantitative real-time polymerase chain reaction. Main Outcome Measure: The main outcome measure was DNA methylation. Results: CYP11B2 methylation levels were significantly lower in APA than in other adrenal tissues (P