Definition

An inherited disorder that increases the risk of developing colorectal cancer, endometrial cancer, ovarian cancer, and many other types of cancer, such as cancers of the stomach, small intestine, pancreas, bile duct, urinary tract, and brain, often before age 50. Hereditary nonpolyposis colorectal cancer is caused by mutations (changes) in genes that affect DNA mismatch repair, a process that fixes mistakes that occur when DNA is copied. These genes are MLH1, MSH2, MSH6, PMS2, and EPCAM. Also called HNPCC and Lynch syndrome.