About Lynch Syndrome

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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.

Understanding Lynch syndrome

Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer, 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.

Cancers that can be related to Lynch syndrome 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.1 These numbers are based on estimates that Lynch syndrome accounts for about 2% to 5% of colorectal cancers and about 3% of endometrial cancers.2

Causes

Hereditary cancer means cancer runs in your family. We do not yet know all of the genes that can cause colorectal cancer, so knowing your family history is very important.

Sometimes cancer happens because of a change in certain genes that you inherit from your mother or father. Genes act like instructions. They tell the body how to build and maintain cells. Every person gets 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—such as blood type, hair color, eye color, and risks of getting certain diseases—will be passed on from parents to children.

Lynch syndrome happens when someone inherits a change (mutation) 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 these mutations.

A male scientist in a white lab coat examines a blood sample at a laboratory
Lynch syndrome happens when someone inherits a change in certain genes. Genetic testing may find these mutations.

More information

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Content Source:
National Center for Chronic Disease Prevention and Health Promotion; Division of Cancer Prevention and Control
  1. U.S. Cancer Statistics Working Group. U.S. Cancer Statistics Data Visualizations Tool. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention and National Cancer Institute; www.cdc.gov/cancer/dataviz, released in June 2025.
  2. Wang C, Wang Y, Hughes KS, Parmigiani G, Braun D. Penetrance of colorectal cancer among mismatch repair gene mutation carriers: a meta-analysis. JNCI Cancer Spectr. 2020;4(5):pkaa027.