Hormone receptor-positive breast cancer occurs when breast cancer cells have hormone receptors, which are special proteins to which the estrogen hormones bind. Some breast cancer cells need estrogen and/or progesterone to grow. A pathologist determines the hormone receptor status by testing the tumor tissue removed during a biopsy.
These breast cancers have many hormone receptors.
These breast cancers have few or no hormone receptors.
Nearly two-thirds of invasive breast cancers are classified as hormone receptor-positive, including both estrogen receptor-positive (ER+) and progesterone receptor-positive (PR+) status. ER+ and PR+ tumors have a better prognosis and can require less aggressive treatment than hormone-negative cancers.