MLH1 (Lynch Syndrome): Cancer Risks
Cancer Risk Associated with Inherited MLH1 Mutations
People with an mutation have . MLH1 mutations increase the risk for colorectal, endometrial and other types of cancer listed in the table below.
Experts at the National Comprehensive Cancer Network (NCCN) created guidelines which estimate the cancer risks for people with MLH1 mutations. These cancer risk estimates are updated based on the latest research.
If you or a relative have tested positive for an MLH1 mutation, we recommend speaking with a genetics expert. They can look at your personal and family medical history to help you understand and decide on a plan for managing your risk.
Cancer risk table
Cancer Type |
Lifetime Risk with MLH1 Mutation |
Lifetime Risk in General Population |
Average Age of Diagnosis with MLH1 Mutation |
Average Age of Diagnosis in General Population |
Colorectal |
46 - 61% |
4.1% |
44 years |
68 - 72 years |
Endometrial |
34 - 54% |
3.1% |
49 years |
60 years |
Ovarian |
4 - 20% |
1.1% |
46 years |
63 years |
Kidney/ureter |
0.2 - 5% |
1.2% |
59 - 60 years |
Not specified |
Prostate |
4.4 - 13.8% |
12.6% |
63 years |
66 years |
Bladder |
2 - 7% |
2.3% |
59 years |
73 years |
Gastric |
5 - 7% |
0.8% |
52 years |
68 years |
Small bowel |
0.4 - 11% |
0.3% |
47 years |
60s - 70s |
Brain |
0.7 - 1.7% |
0.5% |
No data |
59 years |
Biliary tract |
1.9 - 3.7% |
No data |
50 years |
70 - 72 years |
Pancreatic |
6.2% |
1.5% |
No data |
71 years |
Source: NCCN Guidelines: Genetic/Familial High-Risk Assessment: Colorectal, Endometrial, and Gastric; v. 3, 2024. |
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Other cancers
People with an inherited MLH1 mutation may have an increased risk for other cancers. The exact risks for the following cancers are unknown:
- sebaceous skin growths
- breast cancer
Research on how inherited mutations in the MLH1 gene affect cancer risk is ongoing.
It is important to note that cancer risks are estimates over the course of a person's lifetime. Your lifetime risk and risk over the next five years will vary depending on:
- current age
- gender
- specific mutation
- personal and family health history
- diet, exercise, lifestyle and other factors