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ER/PR (hormone receptors) testing: what it means for you

Waiting on test results can feel like one more hard thing, for you and the people who love you. Here's what the ER/PR (hormone receptors) test looks for and how it can help your care team pick the treatment most likely to work for you.

ℹ️ General information to help you and your loved ones talk with your care team, not medical advice. Read our disclaimer.

Matters most in: Breast cancer

The quick guide

What the test looks for: Whether breast cancer cells have receptors for the hormones estrogen (ER) and progesterone (PR). A tissue stain shows what share of cells have them.

Why it matters

Most breast cancers are hormone receptor-positive, which means hormones help them grow. These cancers can usually be treated with hormone therapy, which blocks or lowers estrogen. Cancers without ER, PR or HER2 are called triple-negative and are treated differently.

Treatments it can point to

Hormone therapy such as tamoxifen or an aromatase inhibitor (letrozole, anastrozole, exemestane) (Tamoxifen)
For advanced HR-positive cancer, a CDK4/6 inhibitor added to hormone therapy (Ibrance (palbociclib), Verzenio (abemaciclib))
If advanced cancer develops an ESR1 mutation (found with a blood or tissue test), newer hormone pills such as elacestrant

Only your care team can say which treatment fits you. Drug approvals depend on cancer type, stage and prior treatment.

Tissue vs. blood testing

Tissue from the biopsy or surgery.

Most tests use a piece of tumor tissue from a biopsy or surgery. Some can also use a blood sample (a 'liquid biopsy') that looks for tumor DNA floating in the blood. Blood tests are easier and faster, but they can miss a change that a tissue test would find, so a negative blood test is often followed by a tissue test.

❓ Questions you and your loved ones can ask

Is my cancer ER-positive, PR-positive or both?
How long will I take hormone therapy?
When will my results be back, and will treatment wait for them?
Will my insurance cover this test?

Written by the Cancer Side Effects Guide team from FDA labels and leading cancer centers. Not medical advice. · Last updated: October 15, 2026 · How we write

Not medical advice. This page is general information to help you talk with your care team. It can't replace advice from your doctor or nurse. If you have a fever of 100.4°F (38°C) or higher during treatment, or any symptom that worries you, call your care team now. In an emergency, call 911.