Breast Cancer Hormone Receptor Status
Hormone receptors are proteins inside and on the surface of a breast cancer cell. If a breast cancer has hormone receptors, estrogen, progesterone, or both can make the cancer grow and divide.
Hormone receptors: estrogen and progesterone
Your pathology report will include the results of a test that tells you if the breast cancer cells have receptors for the hormones estrogen and progesterone. Hormone receptors are proteins — found inside and on breast cells — that pick up signals from the hormones telling the cells to grow.
A breast cancer is estrogen receptor-positive if it has receptors for estrogen. This means that the cancer cells, like normal breast cells, may receive signals from estrogen that tell the cells to grow.
A cancer is progesterone receptor-positive if it has progesterone receptors. Again, this means that the cancer cells receive signals from progesterone that tell them to grow. Roughly two out of every three breast cancers test positive for hormone receptors.
A breast cancer is called hormone receptor-positive if it has receptors for estrogen, progesterone, or both.
A breast cancer is called hormone receptor-negative if it doesn’t have estrogen or progesterone receptors.
What hormone receptors do
Hormone receptors, like other cell receptors, are special proteins found in and on the surface of certain cells throughout the body, including breast cells. These receptor proteins are like the eyes and ears of the cells, receiving messages from hormones and other substances in the bloodstream and then telling the cells what to do. The receptors act like an on-off switch for an activity in the cell. If the right substance comes along that fits into the receptor — like a key fitting into a lock — the switch is turned on and that particular activity in the cell begins.
Why is hormone receptor status testing important?
Testing for hormone receptors is important because the results help you and your doctor decide whether the cancer is likely to respond to hormonal therapy medicines.
It’s important to know that some hormone receptor-positive breast cancers can lose their receptors over time. The opposite is also true: Hormone receptor-negative cancers can develop hormone receptors.
If breast cancer comes back after treatment, it's a good idea to ask your doctor about another biopsy to test the cancer for hormone receptors. If the cancer cells no longer have receptors, hormonal therapy is unlikely to help treat the cancer. If the cells have developed hormone receptors, hormonal therapy may offer benefits.
How is hormone receptor status determined?
Most labs use a special staining process that makes hormone receptors show up in a sample of breast cancer tissue. The test is called an immunohistochemical staining assay, or ImmunoHistoChemistry (IHC). Not all labs use the same method for analyzing the results of the test, and they don't report the results in exactly the same way. So you may see any of the following on your pathology report:
A percentage that tells you how many cells out of 100 stain positive for hormone receptors. You will see a number between 0% (none have receptors) and 100% (all have receptors).
An Allred score between 0 and 8. The system looks at what percentage of cells test positive for hormone receptors, along with how well the receptors show up after staining, called intensity. The higher the score, the more receptors were found and the easier they were to see in the sample.
The word positive or negative.
What do hormone receptor test results mean?
In general, hormone receptor-positive means at least 1% of the cells in the sample have estrogen receptors, progesterone receptors, or both. Hormone receptor-negative means that less than 1% of the cells in the sample have hormone receptors.
Sometimes the lab report will say the hormone receptor status is unknown. If you receive an unknown result for hormone receptor status, ask your doctor what it means and what additional steps should be taken to determine the hormone receptor status of the cancer.
Keep in mind that the breast cancer should be tested for both estrogen receptors and progesterone receptors. If your result is reported as just positive or negative, ask your doctor for a more definite percentage, rating, or other number. You also can ask about how these more precise results might influence treatment decisions for your particular situation.
You may see the following terms in your pathology report.
About 70%-80% of breast cancers have estrogen receptors, including cases in men and people assigned male at birth.
More than 50% of breast cancers have receptors for both estrogen and progesterone.
About 2%-8% of breast cancers have receptors for progesterone but not estrogen.
About 15% of breast cancers don’t have estrogen or progesterone receptors. These cancers are called hormone receptor-negative.
Treatments for hormone receptor-positive breast cancer
Hormonal therapy, also called anti-estrogen therapy, endocrine therapy, or hormone therapy, is used to treat all stages of hormone receptor-positive breast cancer.
Hormonal therapy medicines work in two ways:
by blocking estrogen production in the body
by blocking the effects of estrogen on breast cancer cells
Hormonal therapy usually is not a treatment option for hormone receptor-negative breast cancer.
There are three main types of hormonal therapy medicines used to treat breast cancer:
selective estrogen receptor modulators (SERMs)
aromatase inhibitors
estrogen receptor downregulators (ERDs)
Selective estrogen receptor modulators (SERMs) block the effects of estrogen on breast cancer cells by sitting in the estrogen receptors. If a SERM is in the estrogen receptor, estrogen can’t attach to the cancer cell and the cell doesn’t receive estrogen’s signals to grow and multiply.
SERMs can be used to treat both pre- and post-menopausal women, as well as men.
Aromatase inhibitors work by blocking the enzyme aromatase, which turns the hormone androgen into small amounts of estrogen in the body. Aromatase inhibitors can’t stop the ovaries from making estrogen, so these medicines are mainly used to treat post-menopausal women because their ovaries aren’t producing estrogen anymore. Still, if a man with breast cancer isn’t a good candidate for a SERM, his doctor may recommend an aromatase inhibitor.
Selective estrogen receptor degraders or downregulators (SERDs), much like SERMs, block the effects of estrogen on breast cancer cells by sitting in the estrogen receptors. SERDs also lower the number of estrogen receptors and change the shape of breast cell estrogen receptors so they don’t work as well.
CDK4/6 inhibitors are a type of targeted therapy used to treat certain types of hormone receptor-positive, HER2-negative breast cancer. Targeted therapies are medicines that target specific characteristics of cancer cells, such as a protein that allows the cancer cells to grow in a rapid or abnormal way. Targeted therapies are generally less likely than chemotherapy to harm normal, healthy cells. Some targeted therapies are antibodies that work like the antibodies made naturally by our immune systems. These types of targeted therapies are sometimes called immune targeted therapies. CDK 4/6 inhibitors are almost always prescribed along with a hormonal therapy medicine.
CDK4/6 inhibitors interfere with the way breast cancer cells divide and multiply. To do this, they target specific proteins known as the cyclin-dependent kinases 4 and 6, which is abbreviated as CDK4/6.
Treatments for hormone receptor-negative breast cancer
There are no treatments designed specifically for breast cancers without hormone receptors. But the cancer may have other characteristics, such as HER2 receptors, that mean certain targeted therapy medicines are likely to be effective. Also, treatments such as surgery, radiation therapy, chemotherapy, and immunotherapy may be used to treat hormone receptor-negative breast cancer.
— Last updated on July 30, 2025 at 4:04 PM