Triple-negative breast cancer
In triple-negative breast cancer (TNBC), the cancer cells do not contain receptors for estrogen, progesterone, or HER2. About 10 – 20 percent of all breast cancers are triple-negative. This type of breast cancer is usually invasive and usually begins in the breast ducts.
Healthy breast cells contain receptors for the hormones estrogen and progesterone. They also contain receptors for a protein called HER2, which stimulates normal cell growth. About two out of three women with breast cancer have cells that contain receptors for estrogen and progesterone, and about 20 – 30 percent of breast cancers have too many HER2 receptors.
Triple-negative breast cancer treatment options
Breast cancer that is estrogen receptor (ER) and progesterone receptor (PR) positive can be treated with hormone therapies. Breast cancer with excess amounts of HER2 can be treated with anti-HER2 drugs such as trastuzumab.
In women with triple-negative breast cancer, the malignant cells do not contain receptors for estrogen, progesterone or HER2. Breast cancer that is ER, PR and HER2 negative cannot be treated with hormone therapies or medications that work by blocking HER2, such as trastuzumab.
Fortunately, triple-negative breast cancer can be treated with other drugs, such as chemotherapy, radiation therapy and non-HER2 targeted therapy.