MLH1 and colorectal neoplasm: For example, RB1 mutated and hypermethylated retinoblastomas phenocopy each other [37], colorectal tumours with either mutated or hypermethylated MLH1 have microsatellite instability (MSI) [32] and VHL hypermethylation occurs in renal cancers of the clear cell histological subtype as do VHL mutations [41].