Glossary Term:


selective estrogen receptor modulator (SERM)



A drug used in hormone therapy that blocks estrogen from telling breast cancer cells to grow and divide. Acts like an anti-estrogen in breast cells but like an estrogen in other tissues, like the uterus and the bones. Can be used to treat women with breast cancer who have or have not gone through menopause. Tamoxifen is the most commonly used SERM.