PITX1 and Familial adenomatous polyposis: It has also been found that the colonic mucosa of patients with familial adenomatous polyposis (FAP) is enriched with biofilms composed of E.coli and B. fragilis carrying the oncotoxin genes for secreting colibactin and Bft. Both toxins create opportunities for pathogens to invade the mucus layer of the colon and colonize the polyp, with interleukin-17 secretion leading to DNA damage, and thus accelerating the early onset and progression of the tumor [86].