Inactivation of the Escherichia coli homologue of MYH leads to G : C → T : A mutations and adenomas from MYH polyposis patients display a significant excess of G : C → T : A transversions in the adenomatous polyposis coli (APC) gene, as compared to sporadic or familial adenomatous polyposis (FAP)-associated colorectal tumours (Al-Tassan et al, 2002; Jones et al, 2002). The gene discussed is APC; the disease is adenoma.