ABSTRACT
COLORECTAL CANCER IS CLASSIFIED IN TO THREE FORMS: sporadic (70-75%), familial (20-25%) and hereditary (5-10%). hereditary colorectal cancer syndromes classified into two different subtypes: polyposis and non polyposis. Familial Adenomatous polyposis (FAP; OMIM #175100) is the most common polyposis syndrome, account for <1% of colorectal cancer incidence and characterized by germline mutations in the Adenomatous polyposis coli (APC, 5q21- q22; OMIM #175100). FAP is a dominant cancer predisposing syndrome which 20-25% cases are de novo. There is also another polyposis syndrome; MUTYH associated polyposis (MAP, OMIM 608456) which it is caused by mutation in human Mut Y homologue MUTYH (MUTYH; OMIM 604933) and it is associated with multiple (15-100) colonic adenomas. In this paper we discuss MUTYH mechanism as an important member of Base Excision Repair (BER) family and its important role in polyposis condition.
