Biomarker Resource Center
Endometrial Cancer Biomarkers
Reviewed by XpertPatient Medical Advisory · Updated August 2026 · Primary Source: cancer.gov
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What Is a Biomarker — and Why Does It Matter for Your Treatment?
A biomarker is a signal found in your tumor tissue. In endometrial cancer, biomarker testing places your cancer into one of four molecular groups, each with its own best care approach.
Think of it like a clue. Your doctor collects clues from your biomarker test results. Those clues help build a picture of your cancer. That picture helps you have a more informed conversation with your care team about next steps.
How a Biomarker Test Works
A biomarker is a signal your cancer leaves behind. Your doctor finds it through a biopsy or blood test, reads your results, and uses them to choose the treatment most likely to work for your specific tumor.
Why Do Biomarkers Matter in Endometrial Cancer?
Your molecular group can change how much treatment you need and whether immunotherapy is an option. Knowing your group helps your doctor plan your care.
The most important endometrial cancer biomarkers include PTEN status, MSI testing, and your molecular subtype. Together they help your doctor understand how your tumor is likely to behave.
A good question to ask your doctor: Ask your doctor whether your tumor has been molecularly classified and which of the four groups your cancer belongs to.
Quick Poll
Have you been biomarker tested?
Knowing your molecular subtype is one of the most important steps after an endometrial cancer diagnosis.
Source: DaCosta Byfield et al., JAMA Network Open, July 2025 · overall advanced cancer biomarker testing rate (n=26,311) · jamanetwork.com
The Tests Your Doctor May Order
Which of the four molecular groups does your cancer belong to?
The four groups are: POLE-mutated (best outlook), MSI-H (responds well to immunotherapy), NSMP (middle risk), and p53-mutated (more aggressive). Ask your doctor which group your tumor belongs to and what that means for your care.
Does your cancer respond to immunotherapy?
About 25% of endometrial cancers are MSI-H. If your tumor is MSI-H, immunotherapy may be an important option for your care. Ask your doctor whether MSI testing has been done and what your result means.
Is a key tumor-stopping gene changed in your tumor?
PTEN normally helps stop cancer from growing. It is changed in up to 80% of endometrial cancers. Ask your doctor whether PTEN was tested and what the result means for your care.
Sources: National Cancer Institute · SGO · American Cancer Society
Watch & Learn
Common Questions
Endometrial Cancer Biomarkers — Your Questions Answered
What are the four molecular subtypes?
(1) POLE-mutated — best outlook. (2) MSI-H/dMMR — responds well to immunotherapy. (3) NSMP — middle risk. (4) p53-mutated — more aggressive, needs more intensive care.
Should I ask about molecular testing for early-stage cancer?
Yes. Even in early stages, your molecular subtype guides decisions about your care. Ask your doctor if this testing has been done.
What is a POLE mutation?
A specific POLE mutation creates errors that make the cancer very visible to your immune system — leading to the best outcomes of all four subtypes.
Is there patient support for endometrial cancer?
Yes. The Foundation for Women’s Cancer at foundationforwomenscancer.org is a trusted resource.
Knowledge Check
Test what you’ve learned
Three quick questions to help you feel more confident talking with your care team.
How many molecular groups does endometrial cancer have?
Based on what you just read, into how many groups can endometrial cancer be classified?
Which molecular group has the best outlook?
Based on what you just read, which group tends to have the most favorable prognosis?
What does MSI-H mean for endometrial cancer?
Based on what you just read, why does MSI-H matter?
Keep these in mind for your next appointment.
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