ES08 MICRORNA MICROARRAY ANALYSIS OF HUMAN ADRENOCORTICAL TUMOURS

Abstract

Purpose: A dilemma in the management of adrenal tumours is differentiating between benign and malignant tumours. Adrenocortical adenomas (ACAs) are common while adrenocortical carcinomas (ACCs) are rare. ACCs also have poor prognosis with limited treatment options. MicroRNAs (miRs) are non‐coding, 20–22 nucleotide RNAs which have been implicated in tumorigenesis. The aim of this study was to use microarray analysis to identify miRs which play a role in the pathogenesis of ACCs and have the ability to discriminate between ACCs and ACAs as well as to serve as therapeutic targets.Methodology: RNA from 6 normal adrenal cortices, 27 ACAs and 22 ACCs were hybridised to Exiqon mirCURYTM LNA Arrays version 10.0.Results: 14 miRs were significantly upregulated while 9 were significantly downregulated between ACCs and ACAs. Several miRs which have previously been reported to be associated with other cancers and act as regulators of genes such as EGFR, PTEN and RAS were found in our group of significantly differentially expressed miRs. One of the significantly downregulated miRs is located in a 10.4 megabase common minimal region of loss on 17p13 which we have previously delineated in ACCs. In addition, one of the 14 significantly upregulated miRs was located in an intron of IGF2, a gene frequently overexpressed in ACCs compared to ACAs.Conclusions: In this study, we found miRs which were significantly differentially expressed between ACCs, ACAs and normal adrenal cortex, indicating that miRs are involved in the pathogenesis of adrenocortical tumours and have the potential to serve as diagnostic markers and therapeutic targets.