Study of IGF-II growth factor expression and SF-1 and DAX-1 transcription factors in adrenocortical tumors in children and adults

Abstract

Adrenocortical tumorigenesis has been intensively investigated in last 10 yr. Loss of heterozygosity of the 11p15 locus leading to IGF-II gene over expression has been found in 93% of the malignant adrenocortical tumors and 8.6% of the benign tumors. However, the role of IGF-II expression in childhood adrenocortical tumorigenesis is yet to be determined. The transcription factors SF-1 and DAX-1, orphan members of the steroid nuclear receptor superfamily, which regulate the expression of adrenal hydroxylases, are essential for the development and differentiation of the adrenal cortex. SF-1 gene maps to 9q33.3, which is a region that has shown gain in childhood adrenocortical tumors. The aim of this study is to perform a quantitative analysis of IGF-II, SF-1 and DAX-1 gene expression and establish the prognostic value of these molecular markers in Brazilian adults and children with adrenocortical tumors. Fifty patients, adults or children of both sexes, with sporadic adrenocortical tumors will be studied. Representative samples of the adrenocortical tumors will be obtained during surgical procedure (adrenalectomy). Total RNA will be extracted from the tumor samples frozen in liquid nitrogen and cDNA synthesis will be carried out using reverse transcription. The IGF-II, SF-1 and DAX-1 gene expression will be determined by quantitative real-time PCR using a Taqman assay. (AU)