What kinds of breast cancer are fueled by hormones?

Hormone Receptor +: Breast cancer can be differentiated into 2 groups: those that have estrogen and/or Progesterone receptors and those that do not. These receptors are proteins that are present on normal breast cells as well. These natural hormones fit into these receptors like a lock-and-key to stimulate these cells. "anti-estrogen" chemotherapeutics can take advantage of these receptors and disable these cells.

Receptor Positive: Breast cancers that have receptors for estrogen and Progesterone are fueled by hormones. These are the so called er and pr positive tumors. Hormone therapy plays and important role in the treatment of these types of breast cancers.