Breast cancers can be characterized by genetic markers or proteins (hormone receptors) on cancer cells. If your cancer has tested positive for estrogen receptors (ER+) or progesterone receptors (PR+), then it is called hormone receptor positive (HR+). This means that the cancer cells may receive signals from estrogen or progesterone that promote cancer cell growth. If your cancer tests negative for estrogen and progesterone receptors, it is called hormone receptor negative (HR-) breast cancer.

Similarly, if your cancer has tested positive for human epidermal growth factor receptor-2 (HER2), then it is called HER-2 positive (HER2+) breast cancer. In this case, there may be too many HER2 receptors causing cancer cells to grow. If your cancer tests negative, it is called human epidermal growth factor receptor-2 negative (HER2-) breast cancer.

If your cancer tests negative for the ER, PR and HER2 receptors, it is considered triple negative breast cancer.

There are specific treatments for women living with HR+ or HER2+ status, so knowing your treatment status can help you and your health care provider make treatment decisions. To learn more about the subtypes of breast cancer, visit the Know Your Type page.