Key points
- Lynch syndrome is the most common cause of hereditary colorectal (colon) cancer.
- People with Lynch syndrome are more likely to get colorectal, uterine (endometrial), and other cancers.
What Lynch syndrome is
Lynch syndrome, also known as hereditary non-polyposis colorectal cancer (HNPCC), is the most common cause of hereditary colorectal (colon) cancer. People with Lynch syndrome are more likely to get certain cancers and to get them before age 50.
Lynch syndrome-related cancers include:
- Colorectal
- Uterine (endometrial)
- Ovarian
- Stomach (gastric)
- Small intestine
- Urinary tract (kidney, ureter, bladder)
- Biliary tract (liver, gall bladder, bile ducts)
- Pancreatic
- Prostate
- Brain
- Certain types of skin cancers
Lynch syndrome causes about 3,800 colorectal cancers and 1,600 uterine (endometrial) cancers per year.
Causes
Hereditary cancer means cancer runs in your family. We don't know all of the genes that cause colorectal cancer, so knowing your family history is very important.
It could be caused by a change in certain genes that you inherited from your mother or father. Genes act as instructions and contain information to build and maintain cells in the body. Humans inherit one set of genes from their mother and one set of genes from their father.
Genes are made up of DNA. DNA tells the body what traits will be passed on from parents to children, such as blood type, hair color, eye color, and risks of getting certain diseases.
Lynch syndrome is due to inherited changes (mutations) in the genes that normally fix mistakes made when DNA is copied. These genes (MLH1, MSH2, MSH6, PMS2, and EPCAM) normally protect you from getting certain cancers, but some mutations in these genes prevent them from working properly.
Colorectal cancer also can be caused by changes in other genes. For example, familial adenomatous polyposis is caused by mutations in APC and MUTYH genes. Genetic testing may find the mutation.