MLH1 and colorectal cancer: Although inherited mutations in the tumor suppressor gene (TSG) APC (adenomatous polyposis coli), an important component of the Wnt/β-catenin signaling pathway, and the mismatch repair (MMR) genes (e.g. MLH1, mutL homolog 1), which control the mutation rate in a cell [2] may confer a high lifetime risk of cancer with an early age at onset, colorectal cancer is clearly a disease of increasing age [3,4].