Hereditary non-polyposis colon cancer (HNPCC), also known as Lynch syndrome, is caused
by changes in genes that normally help a cell repair faulty DNA. Cells must make a new
copy of their DNA each time they divide into 2 new cells. Sometimes errors are made when
copying the DNA code. Fortunately, cells have DNA repair enzymes that act like
proofreaders or spell checkers. A mutation in one of the DNA repair enzyme genes like
MLH1, MSH2, MLH3, MSH6, PMS1, or PMS, may allow DNA errors to go uncorrected.
These errors will sometimes affect growth-regulating genes, which may lead to the
development of cancer. TGFBR2 is another gene linked to HNPCC. It helps regulate cell
growth.