Lynch Syndrome

What is Lynch Syndrome?

Lynch Syndrome is the most common type of hereditary colorectal and uterine cancer syndrome. Although Lynch Syndrome is primarily associated with colorectal and uterine cancers, it has also been associated with an increased risk of ovarian cancer and cancers of the stomach, small intestine, urinary tract, hepatobiliary tract, skin, and brain. Individuals with Lynch Syndrome tend to develop cancers earlier in life. It is estimated that the prevalence of Lynch Syndrome is approximately 1/370.

There are four major genes involved in the development of Lynch Syndrome: MLH1, MSH2, MSH6, and PMS2. Recently, a new gene—EPCAM—was discovered to cause Lynch Syndrome. An inherited mutation in one of these mismatch repair genes means that the body is not able to properly repair DNA. Put simply, the Mismatch Repair genes normally help prevent cancer—which is why Lynch Syndrome is associated with a higher risk of some cancers.

There is a 50 percent chance that a person with Lynch Syndrome will pass the mutation on to their children. Lynch Syndrome does not skip generations and it affects males and females equally.

Cancer Risk and Lynch Syndrome

Lynch Syndrome is not a guarantee of developing cancer, but it does increase a person’s lifetime risk. Below are the lifetime risks associated with Lynch Syndromes. These risks can vary depending on which of the mismatch repair genes runs in your family.

  • Colorectal Cancer: up to an 80% lifetime risk with an average age at diagnosis at about 45 years.
  • Uterine Cancer: up to a 40-60% lifetime risk
  • Ovarian Cancer: up to 24% lifetime risk • Small intestine: up to a 6% lifetime risk
  • Urinary tract: up to a 7% lifetime risk
  • Hepatobiliary tract: up to a 4% lifetime risk
  • Pancreas cancer: up to a 6% lifetime risk
  • Skin cancer: up to a 9% lifetime risk
  • Brain Tumors: up to a 3% lifetime risk

Lynch Syndrome Cancer Risks based upon NCCN Guidelines Version 1.2014