APC and polyp: Its loss or inactivation has been linked to hereditary predisposition to polyp development and nonclassical polyposis syndromes unrelated to common mutations in genes such as APC or MLH1. 3Furthermore, BMPR2 inactivation has been described in advanced stages of the adenoma-carcinoma sequence, and certain BMPR2 polymorphisms have been associated with increased colorectal cancer risk.4