As part of your testing, you’ll be checked to see if your breast cancer cells have “hormone receptors” — proteins that receive signals that tell the cancer cells to grow — for the two hormones estrogen and progesterone. Breast cancer cells can contain receptors for one, both, or neither of these hormones.
- Estrogen receptor. If the breast cancer has receptors for estrogen, it’s called estrogen receptor positive (or ER positive.) If the breast cancer doesn’t have receptors for estrogen, it’s called estrogen receptor negative (or ER negative.)
- Progesterone receptor. If breast cancer has receptors for progesterone, it’s called progesterone receptor positive (or PR positive.) If breast cancer doesn’t have receptors for progesterone, it’s called progesterone receptor negative (or PR negative.)
Breast cancer that has one or both receptors is called hormone-receptive positive (also called hormone-positive or HR+). Breast cancer that contains neither the estrogen nor the progesterone receptor is called hormone-receptor negative (also called hormone-negative or HR-).
Treatments. For ER positive, HR positive or breast cancer that’s positive for both estrogen and progesterone receptors, treatment could include hormone therapy — drugs that lower estrogen levels or block estrogen receptors. For HR negative, ER negative and PR negative breast cancers, hormone therapy drugs are not effective treatment. Instead, treatments including surgery, radiation therapy, and chemotherapy may be used.
HER2/neu positive. HER2/neu is a gene in breast cells that produces a protein called HER2 that normally controls growth in healthy breast cells. When too much of this protein is produced, it often results in a cancer called HER2 positive. HER2 positive breast cancer is typically treated with therapy drugs that help block HER2 receptors.
Luminal tumors (A&B)
- Luminal A tumors are hormone-receptor positive (estrogen-receptor and/or progesterone-receptor positive), HER2 negative. Luminal A cancers grow slower than Luminal B cancers and tend to have a better prognosis.
- Luminal B tumors breast cancer are hormone-receptor positive (estrogen-receptor and/or progesterone-receptor positive), and either HER2 positive or HER2 negative. Luminal B cancers generally grow faster than luminal A cancers and they tend to have a slightly worse prognosis.
Triple negative breast cancer
Some breast cancers are called triple negative because they don’t have receptors for estrogen, progesterone, or HER2. Because they don’t respond to drugs that target estrogen, progesterone, or HER2 receptors, they can be harder to treat. Chemotherapy is the main treatment option.
When treatment is given before surgery, it’s called neoadjuvant therapy. It can help down stage the disease in the breast and minimize surgical impact and can take the form of chemotherapy, HER2-targeted therapy or hormone therapy.