What genes are involved in hereditary nonpolyposis colorectal cancer?
The genes that cause hereditary nonpolyposis colorectal cancer are called “mismatch repair” genes, or MMR genes for short. MMR genes make proteins that are responsible for correcting mistakes in the DNA when a cell divides into two. If these genes don’t work, each generation of cells will make more errors in the DNA sequence. Eventually, these cells could start to grow out of control and become a tumor. The two most common mismatch repair genes MLH1 and MSH2 account for almost 90% of cases. Other MMR genes associated with hereditary nonpolyposis colorectal cancer include MSH6 and PMS2. MSH6 is found in almost 10% of families with hereditary nonpolyposis colorectal cancer, while PMS2 is less common. There are other MMR genes, but their connection to hereditary nonpolyposis colorectal cancer is not as clear. What are the risks associated with having these altered genes?
