In what a cell increases the number of hormone receptors and becomes more sensitive to the hormone?

Breast cancer cells taken out during a biopsy or surgery will be tested to see if they have certain proteins that are estrogen or progesterone receptors. When the hormones estrogen and progesterone attach to these receptors, they stimulate the cancer to grow. Cancers are called hormone receptor-positive or hormone receptor-negative based on whether or not they have these receptors (proteins). Knowing the hormone receptor status is important in deciding treatment options. Ask your doctor about your hormone receptor status and what it means for you.

What are estrogen and progesterone receptors?

Receptors are proteins in or on cells that can attach to certain substances in the blood. Normal breast cells and some breast cancer cells have receptors that attach to the hormones estrogen and progesterone, and need these hormones for the cells to grow.

Breast cancer cells may have one, both, or none of these receptors.

• ER-positive: Breast cancers that have estrogen receptors are called ER-positive (or ER+) cancers.
• PR-positive: Breast cancers with progesterone receptors are called PR-positive (or PR+) cancers.
• Hormone receptor-positive: If the cancer cell has one or both of the receptors above, the term hormone-receptive positive (also called hormone-positive or HR+) breast cancer may be used.
• Hormone receptor-negative: If the cancer cell does not have the estrogen or the progesterone receptor, it's called hormone-receptor negative (also called hormone-negative or HR-).

Keeping the hormones estrogen and progesterone from attaching to the receptors can help keep the cancer from growing and spreading. There are drugs that can be used to do this.

Why is knowing hormone receptor status important?

Knowing the hormone receptor status of your cancer helps doctors decide how to treat it. If your cancer has one or both of these hormone receptors, hormone therapy drugs can be used to either lower estrogen levels or stop estrogen from acting on breast cancer cells. This kind of treatment is helpful for hormone receptor-positive breast cancers, but it doesn’t work on tumors that are hormone receptor-negative (both ER- and PR-negative).

All invasive breast cancers should be tested for both of these hormone receptors either on the biopsy sample or when the tumor is removed with surgery. About 3 of 4 breast cancers have at least one of these receptors. This percentage is higher in older women than in younger women. DCIS should also be checked for hormone receptors.

How are breast tumors tested for hormone receptors?

A test called an immunohistochemistry (IHC) test is used most often to find out if cancer cells have estrogen and progesterone receptors. The test results will help guide you and your cancer care team in making the best treatment decisions.

What do the hormone receptor test results mean?

Test results will give you your hormone receptor status. It will say a tumor is hormone receptor-positive if at least 1% of the cells tested have estrogen and/or progesterone receptors. Otherwise, the test will say the tumor is hormone receptor-negative.

Hormone receptor-positive (or hormone-positive) breast cancer cells have either estrogen (ER) or progesterone (PR) receptors or both. These breast cancers can be treated with hormone therapy drugs that lower estrogen levels or block estrogen receptors. Hormone receptor-positive cancers tend to grow more slowly than those that are hormone receptor-negative. Women with hormone receptor-positive cancers tend to have a better outlook in the short-term, but these cancers can sometimes come back many years after treatment.

Hormone receptor-negative (or hormone-negative) breast cancers have no estrogen or progesterone receptors. Treatment with hormone therapy drugs is not helpful for these cancers. These cancers tend to grow faster than hormone receptor-positive cancers. If they come back after treatment, it’s often in the first few years. Hormone receptor-negative cancers are more common in women who have not yet gone through menopause.

Triple-negative breast cancer cells don’t have estrogen or progesterone receptors and also don’t make any or too much of the protein called HER2. These cancers tend to be more common in women younger than 40 years of age, who are Black, or who have a mutation in the BRCA1 gene. Triple-negative breast cancers grow and spread faster than most other types of breast cancer. Because the cancer cells don’t have hormone receptors, hormone therapy is not helpful in treating these cancers. And because they don’t have too much HER2, drugs that target HER2 aren’t helpful, either. Chemotherapy can still be useful. See Triple-negative Breast Cancer to learn more.

Triple-positive cancers are ER-positive, PR-positive, and HER2-positive. These cancers can be treated with hormone drugs as well as drugs that target HER2.

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Understanding a Breast Cancer Diagnosis

• Breast Cancer Grades
• Breast Cancer Ploidy and Cell Proliferation
• Breast Cancer Hormone Receptor Status
• Breast Cancer HER2 Status
• Breast Cancer Gene Expression Tests
• Other Breast Cancer Gene, Protein, and Blood Tests
• Imaging Tests to Find Out if Breast Cancer Has Spread
• Breast Cancer Stages
• Breast Cancer Survival Rates
• Questions to Ask Your Doctor About Breast Cancer