Untersuchung der Genexpressionsprofile von adrenokortikalen Tumoren mit der cDNA-Microarray-Technik

Abstract

Adrenocortical carcinoma (ACC) is a rare neoplasm with extremely poor prognosis. The molecular mechanisms of adrenocortical tumorigenesis are still not well understood. The comparative analysis of gene-expression patterns of benign and malignant adrenocortical tumors with cDNA microarrays offers the possibility to identify new tumor-suppressor and proto-oncogenes and to establish reliable diagnostic and prognostic markers. Total RNA from frozen tissue from 10 ACC and 10 benign adrenocortical adenomas was isolated after initial histochemistry revealed a neoplastic cellularity of 95%. The reference contained pooled RNA of 10 normal adrenal cortex samples. Amplified RNA of tumor and reference was used to synthesize Cy3- and Cy5-fluorescently labeled cDNA in a flip-color technique. For hybridization we used D-Chips containing 11,500 unique genes. Chips were scanned using a GMS 418 fluorescent scanner and the images analyzed using IMAGENE 3.0 software. The comparative analysis of gene expression-patterns revealed many candidate genes. For example when comparing ACC to normal adrenal cortex, 42 genes showed a change in expression of greater than 4-fold. In the cases of adenoma vs. normal and ACC vs. adenoma, 11 genes and 21 genes, respectively, displayed changes in expression of greater than 4-fold. Comprehensive expression profiling of adrenocortical tumors using cDNA microarrays is a very powerful technique to elucidate the molecular steps of tumorigenesis and -progression of this ill-defined tumor entity. For establishing reliable diagnostic and prognostic markers to improve the management of patients with adrenocortical tumors, confirmation of the results based on further analysis and correlation with clinical data should be performed.