Analysis of Gene Expression in Renal Cell Carcinomas Using cDNA Microarray: Reduced Expression of Decorin in Renal Cell Carcinomas

ABSTRACT

BACKGROUND: Identification of the genes expressed differentially in renal cell carcinoma (RCC)but not in the non-cancerous kidney is important for understanding the molecular basis ofrenal cell carcinoma and for defining possible prognostic value and therapeutic intervention.We investigated the changes in gene expression accompanying the development and progression of kidney cancer by cDNA microarrays. METHODS: To identify molecular alterations in renal cell carcinoma, we measured expression profiles for paired neoplastic and noncancerouskidney samples from an individual by means of a cDNA microarry representing 7, 500genes. Of the differentially expressed genes, we assessed the decorin gene at the proteinlevel using immunohistochemistry. RESULTS: The 60 genes were noted to have more than a fivefold change in expression (either increased or decreased) in RCC compared to the noncancerouskidney. The changed genes are those associated with signal transduction, metabolizingenzymes, the cytoskeleton, cell adhesion, cell cycle control, modulation of transcription, the tumor suppressor gene and tumor antigens. Under immunohistochemistry, the expressionof decorin was significantly decreased in the tumor than in the non-cancerous kidney.The expression rate of decorin was not associated with the patient's sex, age, histologic type, Fuhrmann nuclear grade and T stage. CONCLUSION: The author predicted that these geneexpression profiling experiments will lead to improvements in the basic understanding of renaltumor pathogenesis and will promote the discovery of novel molecular markers for renal tumordiagnosis and therapy.