Hormone Therapy for Metastatic Breast Cancer Watch Susan G. Komen®’s January 2024 MBC Impact Series, Metastatic Breast Cancer and Estrogen Receptor-Positive Breast Cancer. What is hormone therapy? Estrogen and progesterone are female hormones produced in the body. Some breast cancer cells need estrogen and/or progesterone to grow. When these hormones attach to special proteins called […]