In colorectal tumours, Wnt pathway genetics continues to be dominated by mutations in the adenomatous polyposis coli (APC) gene. Germline mutations cause familial adenomatous polyposis and at least two-thirds of sporadic colorectal tumours also acquire APC mutations, quite possibly as the initiating events in tumorigenesis. These mutations almost always cause loss of the C-terminal functions of the APC protein - probably involved in microtubule binding, cell polarity and chromosome segregatio...