New HERizons: HER2-Positive Breast Cancer and the Legacy of Herceptin


Twenty years ago, no targeted treatments existed for breast cancers with high levels of a protein called HER2 (HER2-positive, or HER2+). The significance of HER2 in breast cancer had only been recognized in 1987, when excessive levels of the protein were identified in about 20% of breast cancers. Oncologists realized that high levels of HER2 mark a type of cancer with a poor prognosis, as compared to the predominant type of breast cancer: estrogen receptor-positive, HER2 negative (HER2-).

The possibility of targeting HER2 to treat cancer was fulfilled in 1998, when the U.S. Food and Drug Administration (FDA) approved Herceptin (generic name trastuzumab), for treatment of metastatic HER2+ breast cancer. Made by Genentech, Herceptin is a type of drug known as a humanized antibody, meaning that it mimics an immune system attack on tumor cells, specifically those with high levels of HER2. Now, 20 years later, it is easier to appreciate the significance of this drug, which literally changed the lives of many HER2+ breast cancer patients, and continues to do so today. Continue reading…