microRNA expression patterns in adrenocortical carcinoma variants and clinical pathologic correlations

Several microRNAs (miRNAs) were shown to be deregulated in adrenocortical carcinoma (ACC) as compared with adenoma, but a detailed assessment of their expression in its histologic variants and correlation with clinicopathologic characteristics has not been performed, so far. Our aim was to assess the expression of 5 selected miRNAs (IGF2 gene–related miR-483-3p and 5p and hypoxia-induced miR-210, miR-195, and miR-1974) in a series of 51 ACCs (35 classical, 6 myxoid, and 10 oncocytic) as compared with clinical and pathologic features and immunohistochemical expression of prognostic markers, including steroidogenic factor 1, p53, β-catenin, and glucose transporter 1. Oncocytic carcinomas had a reduced expression of miR-483-3p (P = .0325), miR-483-5p (P = .0175), and miR-210 (P = .0366), as compared with other histotypes. Overexpression of miR-210was associated with the presence of necrosis (P = .0035), high Ki-67 index (P = .0013), and high glucose transporter 1 expression (P = .0043), whereas an inverse correlation with mitotic rate was observed in cases with high miR-493-3p (P = .0191) and miR-1974 (P = .0017) expression. High miR-1974 was also associated with low Ki-67 (P = .0312) and European Network for the Study of Adrenal Tumors stage (P = .0082) and negative p53 (P = .0013). At univariate analysis myxoid/classic histotype (P = .026), high miR-210 (P = .0465), high steroidogenic factor 1 protein (P = .0017), high Ki-67 (P = .0066), and high mitotic index (P = .0006) were significantly associated the shorter overall survival, the latter being the sole independent prognostic factor at multivariate analysis (P = .017). In conclusion, (a)miR-483-3p, miR-483-5p, and miR-210 are differentially expressed inACC variants, and (b) high miR-210 is associated with clinicopathologic parameters of aggressiveness and a poor prognosis.