PRDM5 and cancer: Of the 10 cancers with retained PRDM5 protein expression, 9 had unmethylated PRDM5. The high rate of PRDM5 protein loss compared to the rate of methylation across all cancers, and the high frequency of absent PRDM5 protein expression observed in unmethylated cancers, clearly indicates that other mechanisms besides methylation are contributing to PRDM5 protein down-regulation.