Lynch Syndrome

February 12, 2026

This page was reviewed under our medical and editorial policy by Joanne M. Jeter, M.D., clinical professor, and Heather Hampel, M.S., C.G.C., professor, Department of Medical Oncology & Therapeutics Research, City of Hope^® Cancer Center Duarte.

Lynch syndrome is a genetically inherited condition that affects about 1.5 million Americans. People who have Lynch syndrome are more likely to develop certain types of cancer, in particular, colorectal and uterine (endometrial) cancer.

What Is Lynch Syndrome?

Lynch syndrome is a hereditary condition, which means that it is passed on from a parent to a child. People with Lynch syndrome have mutations in one of the genes that helps repair damaged DNA. Uncorrected DNA damage can lead to the development of cancer. Lynch syndrome was formerly referred to as hereditary nonpolyposis colorectal cancer (HNPCC).

Does Everyone with Lynch Syndrome Get Cancer?

Having Lynch syndrome does not mean that someone will develop cancer. However, Lynch syndrome does increase the risk for developing certain cancers and the chances that cancer will develop earlier in adulthood. Most significantly, it increases the risk for colorectal cancer in men and women, and uterine (endometrial) cancer in women.

Lynch Syndrome Cancers

Cancer is the result of cells in the body growing abnormally or uncontrollably. Because Lynch syndrome affects some of the genes that control how cells repair themselves, it may increase the risk for developing certain kinds of cancer.

The most significant increase in cancer risk among people with Lynch syndrome is for colorectal cancer. Men with Lynch syndrome have a 20% to 74% risk for developing colorectal cancer during their lifetime, while women have a 20% to 52% chance. Women also have a 20% to 68% risk for developing endometrial (uterine) cancer.

People with Lynch syndrome who have a gene mutation in the MLH1 or MSH2 genes have higher cancer risks than those with a gene mutation in the MSH6 or PMS2 genes. Other cancers that have been associated with Lynch syndrome include stomach, ovarian, bile duct, small intestine, brain, urinary tract, pancreatic, or a certain type of skin cancer.

There is also some evidence that having Lynch syndrome makes it more likely someone will develop some other types of cancer, including prostate cancer.

Gene Mutations

Lynch syndrome causes a mutation in the some of body’s mismatch repair (MMR) genes, which are known as:

• MLH1
• MSH2 (or EPCAM)
• MSH6
• PMS2

Mutations in any of these genes increase a person’s risk for developing colorectal, endometrial and certain other cancers. They also make it more likely cancer will develop at an earlier age in adulthood.

Genetic Testing

Lynch syndrome is diagnosed using genetic tests that may detect gene mutations associated with the condition. Doctors and genetic counselors use several criteria to determine whether testing for Lynch syndrome may be helpful. These include:

• Having a direct family member or several more distant family members with the condition
• A history of certain cancers that may be linked to Lynch syndrome
• Being diagnosed with certain types of cancer at an earlier-than-usual age

Knowing whether or not someone has Lynch syndrome is important because it may help determine whether he or she should be screened earlier or more often for certain kinds of cancer.

Cancer Screening

People with Lynch syndrome should be screened for cancer on a regular basis. Often, screening begins earlier than average or happens more frequently.

In most cases, doctors recommend that people with Lynch syndrome undergo a colonoscopy every one to three years, starting between age 20 and 35, depending on the underlying gene cause. Colonoscopy may detect — and in some cases remove — colorectal cancers.

Doctors may also recommend earlier or more frequent screening for other conditions, such as endometrial cancer, ovarian cancer and gastrointestinal cancers, or potentially hysterectomy to reduce the risk for gynecologic cancers. There may also be medications recommended to lower the risk for Lynch syndrome cancers.