Endometrial Cancer Biomarkers
Molecular classification of endometrial cancer now places tumors into four groups — based on PTEN, MSI-H/dMMR, and POLE status — and each group calls for a different treatment approach.
Reviewed by XpertPatient Medical Advisory · Updated June 2026 · Sources: NCI · ACS · ASCO · NIH/PMC
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What is a biomarker?
A biomarker is a measurable signal in your tumor tissue. In endometrial (uterine) cancer, biomarker testing goes a step further — it classifies your cancer into one of four molecular groups, each with a different outlook and treatment approach.
Doctors used to treat all endometrial cancers similarly. Now we know there are four distinct molecular types — and they behave very differently. Your molecular group can change how much treatment you need, and whether immunotherapy is an option for you.
What this means for you: Ask your doctor: what is my molecular subtype? The answer — POLE, MSI-H, NSMP, or p53-mutated — directly shapes your treatment plan.
The Tests Your Doctor Orders
🔍 Is a key tumor-stopping gene missing or damaged?
PTEN normally stops cancer from growing. It’s lost in up to 80% of endometrial cancers. When PTEN is lost, a growth pathway called PI3K becomes overactive — and drugs targeting that pathway are being studied.
🔍 Does your cancer respond to immunotherapy?
About 25% of endometrial cancers are MSI-H. These tumors respond well to pembrolizumab immunotherapy, which is FDA-approved for dMMR endometrial cancer. This is one of the most important tests to have done.
🔍 Is there a mutation in a cancer growth pathway?
PIK3CA mutations appear alongside PTEN loss in many endometrial cancers. They’re being studied as targets for a new class of drugs called PI3K inhibitors.
Watch & Learn
Common Questions
Endometrial Cancer Biomarkers — Your Questions Answered
What are the four molecular subtypes?
(1) POLE-mutated — best prognosis, may need less treatment. (2) MSI-H/dMMR — responds well to immunotherapy. (3) NSMP — intermediate risk. (4) p53-mutated — most aggressive, needs intensive treatment.
What does MSI-H mean for treatment?
MSI-H endometrial cancer responds to checkpoint immunotherapy like pembrolizumab. It’s FDA-approved for dMMR endometrial cancer after chemotherapy, and is being studied as a first-line treatment.
Do I need molecular testing for early-stage cancer?
Yes. Even for early-stage disease, molecular classification guides decisions about whether you need radiation or chemotherapy after surgery. Ask your doctor whether this testing has been done.
What is a POLE mutation?
POLE is a gene that copies DNA. A POLE mutation leads to many errors that actually make the cancer very visible to your immune system — leading to the best outcomes of all four subtypes.
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