Selected mutations with high risk of colorectal cancer

Colorectal cancer (CRC) is a disease having the second highest mortality rate in developed countries. Twenty-twenty-five percent of CRC cases are hereditary. Often, a predisposition to CRC is conditioned by just one gene mutation, as in familial adenomatous polyposis syndrome bowel disease (FAP), where the key mutation is in the APC gene. Another genetic predisposition to CRC is through hereditary mutations in the MUTYH gene. Not all hereditary colorectal cancer develops on the basis of polyposis. Hereditary colorectal cancer not associated with polyposis (HNPCC) represents 2-4% of cases of CRC. The most common form of HNPCC is Lynch syndrome. This syndrome is caused by mutations in DNA repair genes called the MMR genes. These mutations, known as high-risk, lead to the genomic instability in cells that confers the mutator phenotype. A large number of the remaining hereditary predispositions to CRC are attributed to a combination of much more extensive changes, in genes with lower penetration, that only moderately increase the risk of colorectal cancer.