Colon cancer, a malignant tumor of the large intestine, affects
both men and women. It affects 2-6% of all men and women in
their lifetime. The vast majority of colon cancer cases are not
hereditary. However, approximately 5 percent of individuals with
colon cancer have a hereditary form. In those families, the
chance of developing colon cancer is significantly higher than
in the average person. Identifying those individuals and
families that might be at-risk for hereditary colon and
associated cancers can dramatically reduce the number of cancer
diagnoses in these families. Colon Cancer Genes Several genes
have been identified which contribute to a susceptibility to
colon cancer. The two most common inherited colon cancer
conditions include FAP and HNPCC. - FAP (familial adenomatous
polyposis) Individuals with this syndrome develop many polyps in
their colon (often over 100). People who inherit mutations in
the APC gene have a nearly 100 percent chance of developing
colon cancer by age 40. In addition, havin