National Breast and Ovarian Cancer Centre (NBOCC)

When breast cancer cells have hormone receptors on them, it means the growth of the cancer cells is affected by female hormones. Breast cancer cells with hormone receptors on them are said to be ‘hormone receptor positive’.

There are two types of hormone receptors – oestrogen receptors (ER) and progesterone receptors (PR). Hormonal therapies stop hormone receptor-positive breast cancer cells from growing.