Breast cancer cells that have estrogen receptors. Estrogen receptors are special proteins that the hormone estrogen binds to. Breast cancer cells that are ER+ depend on estrogen to grow. Anti-estrogen hormonal therapy blocks the receptors or reduces the amount of estrogen that can get into the receptors. As a result, the cancer cells may shrink or die.
Read more about hormone receptor status.
Audio contributed by: Marisa Weiss, M.D.