Triple-Negative Breast Cancer
Your pathology report may say that the breast cancer cells tested negative for estrogen receptors (ER-), progesterone receptors (PR-), and HER2, also called human epidermal growth factor receptor 2 (HER2-). Testing negative for all three receptors means you have “triple-negative breast cancer.”
Without these receptors, the cancer’s growth is not likely to be fueled by estrogen or progesterone, or by growth signals coming from the HER2 protein. Therefore, triple-negative breast cancer does not respond to hormonal therapy (such as tamoxifen or aromatase inhibitors) or therapies that target HER2 receptors, such as Herceptin (chemical name: trastuzumab). However, other medicines can be used to treat triple-negative breast cancer.
About 10-20% of breast cancers — more than one out of every 10 — are found to be triple-negative. Researchers are very interested in finding new medications that can treat this kind of breast cancer. Early studies are trying to find out whether certain medications can interfere with the processes that cause triple-negative breast cancer to grow. In this section, you can learn about: