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MSH2 Gene Mutations (Lynch Syndrome)

Learn about the cancer risks, screening, prevention and treatment options for people with Lynch syndrome due to an inherited MSH2 mutation. Stay up to date by signing up for our community newsletter.
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Information about Inherited Mutations 
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What is an MSH2 mutation?

MSH2 is a gene that helps repair damage to your . Inherited mutations in the MSH2 gene cause Lynch syndrome. People with Lynch syndrome have an increased risk for several types of cancer. Other names for Lynch syndrome include:

  • Hereditary Nonpolyposis Colorectal Cancer ()
  • Muir-Torre syndrome, which refers to a subset of Lynch syndrome in which people have an increased risk of developing rare skin tumors.

Which cancers are associated with an MSH2 mutation?

People with an inherited MSH2 mutation have an increased risk for many cancers, especially of the large intestine (the colon and the rectum) and uterus (endometrium). Expert guidelines include estimates of the lifetime cancer risks for people with MSH2 mutations.

Does everyone with an MSH2 mutation develop cancer?

Although the lifetime risk for cancer with an MSH2 mutation is very high, not everyone with the mutation develops cancer. Following the guidelines for screening and prevention increases the chances of preventing cancer or catching it at its earliest and most treatable .

Can MSH2 mutations skip a generation?

MSH2 mutations are passed down from parents to children, but they do not skip generations. Each person with an MSH2 mutation has a 50% chance of passing their mutation on to each of their children. Children who did not inherit their parent's MSH2 mutation cannot pass the mutation to their children. 

People with an MSH2 mutation who never develop cancer can still pass their mutation on to their children. A child who inherits their parent's MSH2 mutation will be at increased risk for cancer. 

What can people with an MSH2 mutation do?

People with an MSH2 mutation have options for screening, prevention and treatment of . There are expert guidelines and clinical trials that focus on:

  • screening and early detection
  • risk-reduction
  • treatment  

There may be other medical concerns, including a rare childhood disease known as “constitutional (CMMRD),” which can happen in people who inherit a mutation in both copies of their MSH2 gene.  

If you test positive for an MSH2 mutation, you should inform your close blood relatives (first-, second-, and third-degree relatives) about your test results and encourage them to speak with a genetics expert.

More detailed information for people with inherited MSH2 mutations is highlighted below. 

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Share Your Test Results with Relatives  ›

Download our sample letter to help you share your MSH2 test results with relatives. 

More Information for People with MSH2 Mutations

Cancer Risks

Cancer risk estimates are updated based on the latest research. Read about the lifetime risk for different cancers in people with and inherited MSH2 mutation. 

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Risk Management Options

Read about the latest expert guidelines for cancer screening and prevention for people with an MSH2 mutation. Learn about research studies enrolling high-risk patients.  

More info

Cancer Treatment Options

Tumor biomarker testing and genetic testing can provide additional clues about which treatments may work best for your cancer. People who test positive for an MSH2 mutation may have additional treatment or clinical trial options available to them. 

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Other Considerations

People who inherit a mutation in both copies of their MSH2 gene—one from each parent—have a rare disease known as  "constitutional mismatch repair deficiency." Learn additional information about inherited MSH2 mutations. 

More info

More Resources

Participate in Prevention Research

The screening and prevention studies below are enrolling people with MSH2 mutations. To search for more studies, visit our Search and Enroll Tool

Watch Our Webinars for People with Lynch Syndrome

What's new for people with Lynch syndrome?

Spotlight on Hereditary Cancer Research

Last updated July 29, 2025