American Cancer Society: “Breast Cancer Facts & Figures 2019-2020,” “Breast Cancer HER2 Status.”
Sara Tolaney, MD, breast medical oncologist, Dana-Farber Cancer Institute, Boston.
National Cancer Institute: “Breast Cancer Treatment (Adult) (PDQ®)–Patient Version,” “Cancer Stat Facts: Female Breast Cancer Subtypes.”
Virginia Kaklamani, MD, professor of medicine, Division of Hematology/Oncology, UT Health, San Antonio, TX.
Journal of Clinical Oncology: “Loss of Human Epidermal Growth Factor Receptor 2 (HER2) Expression in Metastatic Sites of HER2-Overexpressing Primary Breast Tumors.”