Breast cancers can be categorized in a number of ways, one of which being receptor status. This refers to certain proteins on the surface of cells that “receive” things (such as hormones) to fuel the growth of the cancer.
“Think of [receptors] as little baseball mitts that sit on the surface of the cell,” says Amy Tiersten, MD, hematologist and oncologist at Mount Sinai Hospital in New York City. There are three types of receptors that could potentially be on a breast cancer cell: estrogen, progesterone, and HER2/neu.
What Is Hormone Receptor-Positive Breast Cancer?
If breast cancer cells have either many estrogen or many progesterone receptors, this is categorized as hormone receptor-positive breast cancer. This means that the breast cancer is being fueled by either estrogen (ER-positive) or progesterone (PR-positive)—or in many cases, both.
If the cancer cells have neither receptor, this is known as hormone receptor-negative. This might mean they have an overexpression of the HER2/neu protein instead (HER2-positive breast cancer) or they have none of the receptors (triple-negative breast cancer).
Here’s why doctors care about receptor status: Many of the treatments for breast cancer are catered toward the receptor status, so knowing what your receptor status is can help you and your doctor find the most effective treatment for your specific subtype of breast cancer.
Treatments for Hormone Receptor-Positive Breast Cancer
The mainstay of treatment for hormone receptor-positive breast cancer is anti-estrogen medications. There are different types that inhibit the effect of hormones on the cancer cell in various ways.
For example, one type of hormone therapy for breast cancer “blocks the cell’s estrogen receptor from interacting with whatever estrogen is in a woman’s body,” while another kind “actually lowers the amount of estrogen in the person’s body and starves these cells that are dependent upon estrogen to live,” says Dr. Tiersten.
A newer category of drugs that is effective against hormone receptor-positive breast cancer is CDK4/6 inhibitors, which are commonly used for more advanced, metastatic breast cancers. They are used in combination with anti-estrogen therapy and can prolong the effectiveness of the treatment, in order to keep the disease from progressing.