Estrogen Receptor, Progesterone Receptor Tests

Estrogen receptor/progesterone receptor (ER/PR) tests are done on samples of your tissue that contain breast cancer cells. The tests check if your cancer cells have estrogen and progesterone receptors (proteins that estrogen and progesterone attach to). The results of the tests are used to help guide breast cancer treatment.

Receptors are special proteins inside or on the surface of cells. They can attach to certain substances in your blood, including estrogen and progesterone. Estrogen and progesterone are hormones (chemical messengers in your bloodstream that control the actions of certain cells or organs).

These hormones play key roles in a woman's sexual development and reproductive functions. Men also have these hormones, but in much smaller amounts. Breast cancer can affect both women and men.

If a receptor attaches to estrogen and/or progesterone, the receptor may use that hormone to trigger certain breast cancer cells to grow. ER/PR tests will show whether there are ER and/or PR receptors on your breast cancer cells. Test results are frequently referred to as the hormone receptor status.

The different statuses include: ER-positive (ER+): Cancers that have estrogen receptors (ER). Most breast cancers are ER-positive.; PR-positive (PR+): Cancers that have progesterone receptors (PR); Hormone receptor-positive (HR+): Cancers with one or both receptor types.; HR-negative (HR-): Cancers without ER or PR receptors. ; If your hormone receptor status shows you have one or both receptors on your cancer cells, you may respond well to certain treatments.

Why this test is done

You may need this test if you've been diagnosed with breast cancer. Knowing your hormone receptor status will help your health care provider decide how to treat it. If you have ER-positive, PR-positive, or HR-positive cancer, medicines that lower hormone levels or stop the hormones from helping cancer to grow can be very effective.

If you have HR-negative cancer, these types of medicines won't work for you.

How to prepare

Your provider will give you instructions for how to prepare for your biopsy. If you take any blood thinners, including aspirin, you may need to stop taking them before your biopsy. Tell your provider about all the medicines and supplements you take.

Don't stop or start taking anything without talking with your provider first.

If you're having general anesthesia, you will probably need to fast (not eat or drink) for several hours before surgery. If you have general anesthesia or medicine to relax, you may be groggy after the procedure, so plan to have someone take you home.

Sample type

Tissue/Biopsy

Other names for this test

ER/PR IHC testing, hormone receptor status, hormone receptor test, ER/PR test