Which tumour suppressor gene is mutated in families with familial adenomatous polyposis?

Mutations in the APC (adenomatous polyposis coli) gene cause both classic and attenuated familial adenomatous polyposis. These mutations affect the ability of the cell to maintain normal growth and function. Cell overgrowth resulting from mutations in the APC gene leads to the development of multiple colonic polyps. These polyps are not themselves malignant but are prone to develop frank carcinoma through the accumulation of further genetic mutations.