In addition, a recent functional epigenetic study of renal cell carcinoma (RCC) cell lines and primary tumors by high-density gene expression microarrays identified CST6 as one of eight genes that showed frequent (>30%) tumor-specific promoter region hypermethylation associated with transcriptional silencing (epigenetically inactivated candidate RCC TSGs). The gene discussed is CST6; the disease is hereditary clear cell renal cell carcinoma.