Hereditary colorectal cancers.

Individuals with one of the highest known risks of developing colorectal cancer are members of hereditary colorectal cancer families. Familial adenomatous polyposis (FAP) and hereditary nonpolyposis colon cancer (HNPCC) are the most commonly recognized hereditary colorectal cancer syndromes. Surveillance, family identification, and education are of major importance. Genetic screening holds further promise.