Integrative Epigenetic and Gene Expression Analysis of Renal Tumor Progression to Metastasis

Renal cell carcinoma (RCC) is among the ten most common malignancies. By far, the most common histology is clear cell (ccRCC). The Cancer Genome Atlas and other large scale sequencing studies of ccRCC have been integral to the current understanding of molecular events underlying RCC and its biology. However, these data sets have focused on primary RCC which often demonstrates indolent behavior. In contrast, metastatic disease is the major cause of mortality associated with ccRCC. However, data sets examining metastatic tumor are sparse. We therefore undertook an integrative analysis of gene expression and DNA methylome profiling of metastatic ccRCC in addition to primary RCC and normal kidney. Integrative analysis of the methylome and transcriptome identified over 30 RCC specific genes whose mRNA expression inversely correlated with promoter methylation including several known targets of hypoxia inducible factors (HIFs). Notably, genes encoding several metabolism-related proteins were identified as differentially regulated via methylation. Collectively, our data provide novel insight into biology of aggressive RCC. Furthermore, they demonstrate a clear role for epigenetics in the promotion of HIF signaling and invasive phenotypes in renal cancer.

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Nam HY, Chandrashekar DS, Kundu A, Shelar S, Kho EY, Sonpavde G, Naik G, Ghatalia P, Livi CB, Varambally S, Sudarshan S