ES07 MICROARRAY GENE EXPRESSION ANALYSIS OF HUMAN ADRENOCORTICAL TUMOURS

Abstract

Introduction Adrenal tumours are common, occurring in 7% of patients over the age of 50. Adrenocortical carcinomas, however, are rare, with an incidence of two per million population per year. The management of adrenocortical tumours is complex, compounded by the difficulty in discriminating benign from malignant tumours using conventional histology. A molecular marker which could reliably distinguish between the two groups would be valuable in patient management.Objectives The aim of this study was to identify molecular markers which will discriminate between adrenocortical carcinomas and adenomas using microarray gene expression analysis.Methods This study used RNA from 6 normal adrenal cortices, 16 adrenocortical adenomas and 12 carcinomas. Only samples with an RNA integrity number of 7.5 or greater were used. The samples were hybridised to Affymetrix HGU133plus2.0 genechips. Data analysis was performed with Partek and affylmgui softwares.Results Using a cutoff of B > 2 and M > 2 or <−2, 217 genes were found to be significantly differentially expressed between adrenocortical adenomas and carcinomas. Of these genes, 120 were unpregulated while 97 were downregulated. Seven of these genes have been selected for validation studies with real time reverse transcription polymerase chain reaction.Conclusion In this study, we found 217 genes which were significantly differentially expressed between adrenocortical adenomas and carcinomas. With validation and further studies, these genes will provide further insight into the pathogenesis of adrenocortical tumours as well as possibly proving to be reliable discriminators between adrenocortical adenomas and carcinomas.