Are your cancer cells fueled by hormones?

Some breast cancers are sensitive to your body's naturally occurring female hormones — estrogen and progesterone. The breast cancer cells have receptors on the outside of their walls that can catch specific hormones that circulate through your body.

Knowing your breast cancer is sensitive to hormones gives your doctor a better idea of how best to treat the cancer or prevent cancer from recurring.

Hormone status of breast cancers includes:

• Estrogen receptor (ER) positive. The cells of this type of breast cancer have receptors that allow them to use the hormone estrogen to grow. Treatment with anti-estrogen hormone (endocrine) therapy can block the growth of the cancer cells.
• Progesterone receptor (PR) positive. This type of breast cancer is sensitive to progesterone, and the cells have receptors that allow them to use this hormone to grow. Treatment with endocrine therapy blocks the growth of the cancer cells.
• Hormone receptor (HR) negative. This type of cancer doesn't have hormone receptors, so it won't be affected by endocrine treatments aimed at blocking hormones in the body.