From: healthline.com
When breast cancer cells test positive for estrogen receptors, it’s called estrogen receptor-positive (ER-positive) breast cancer. It means that estrogen is fueling the growth of the cancer.
It’s one of several important characteristics of breast cancer that help determine the best treatment options.
In this article, we’ll examine the role of hormone receptors in breast cancer and how they affect treatment and give you a general idea of what to expect.
ER-positive breast cancer is the most common type of breast cancer diagnosed today.
According to the American Cancer Society (ACS), about 2 out of every 3Trusted Source cases of breast cancer are hormone receptor-positive. Most of these cases are ER-positive, meaning that there are estrogen receptors on the surface of the cell that bind to estrogen.
About 80%Trusted Source of breast cancers in women and 90% of breast cancers in men are ER-positive, according to the National Cancer Institute.
How many ER-positive cases are also PR-positive?
Progesterone receptor-positive (PR-positive) breast cancer means that the cancer is using progesterone as fuel. According to BreastCancer.org, about 65% of ER-positive breast cancers are also PR-positive.
Only about 1%Trusted Source of breast cancers are PR-positive but ER-negative.
Estrogen and progesterone are the two hormones associated with breast cancer. If the cancer has either or both receptors, it’s also known as hormone-positive or HR-positive breast cancer. Breast cancers that test negative for both hormone receptors are HR-negative.
Breast cancer is also checked for a protein called human epidermal growth factor receptor 2 (HER2). Too much of this protein can help cancer grow and spread. These cancers are called HER2-positive or HER2-negative.
Breast cancer can also be triple-positive or triple-negative. This means the cancer is either positive or negative for all three of the receptors mentioned earlier.
Hormones are chemical messengers that circulate in the bloodstream. Hormone receptors are proteins located in and around breast cells. When the corresponding hormone binds to its receptor, it tells the cells how to grow and divide.
In the case of breast cancer, these receptors allow abnormal cells to grow out of control, which results in a tumor.
What are estrogen and progesterone receptors?
Estrogen and progesterone are two hormones that can help breast cancer grow. These hormones bind to estrogen and progesterone receptors.
Following a breast biopsy, a pathologist will perform an immunohistochemical staining assay on the tissue sample. This test can detect the presence of estrogen and progesterone receptors.
Hormone receptor status provides a lot of information on how the cancer is likely to behave. It’s also a key factor in determining the best possible treatment.
HR-positive breast cancer typically responds well to hormone therapy. These therapies block the production of the hormones or interfere with their effects on breast cancer cells.
On the other hand, HR-negative breast cancers don’t respond to hormone therapy, so other treatment options will be more effective.
If your doctor suspects breast cancer, you will likely have a biopsy to test for cancerous cells. If they are found, your doctor will also test the cells for characteristics that include what receptors, if any, are present on the surface of the cancer cells.
The outcome of this testing is important when making treatment decisions. What treatment options are available is highly dependent on the test results.
If you have ER-positive breast cancer, your cancer cells grow in the presence of the hormone estrogen. Estrogen occurs naturally in the body. Drugs that interfere with estrogen’s ability to promote cancer cell growth are used to treat ER-positive breast cancers.
Barbara Jacoby is an award winning blogger that has contributed her writings to multiple online publications that have touched readers worldwide.