DNA methylation signature for the assessment of metastatic risk in primary renal cell cancer.

516Background: Transition from localized renal cell cancer (RCC) to metastatic disease is associated with an immense mortality. Beside clinicopathological risk estimation, a molecular prediction of metastatic risk from primary cancers with a sufficient diagnostic accuracy is not available. We biometrically identified a candidate metastasis associated methylation signature (MAMS) in a genome-wide in silico DNA methylation analysis of TCGA data and carried out a double evaluation study using tissues from localized RCC, primary metastatic RCC, and distant metastases. Methods: Candidate MAMS was identified by genome-wide random forest analyses of TCGA methylation level 3 data aiming for classification of 230 primary RCC without distant metastases and 52 metastasized tumors. Forty-nine pyrosequencing and/or quantitative methylation specific PCR analyses were established for a total of 20 candidate methylated loci. For evaluation of MAMS, DNA was isolated and bisulfite converted from the primary RCC tissue coho...