Hormone receptor-positive breast cancer refers to a type of breast cancer that is influenced by the presence of certain hormone receptors on the surface of cancer cells. The two main types of hormone receptors involved in breast cancer are estrogen receptors (ER) and progesterone receptors (PR).

In hormone receptor-positive breast cancer:

1. **Estrogen Receptor-Positive (ER+):** Cancer cells have receptors for the hormone estrogen on their surface. When estrogen binds to these receptors, it can stimulate the cancer cells to grow and divide. Therefore, estrogen receptor-positive breast cancer cells are sensitive to estrogen.

2. **Progesterone Receptor-Positive (PR+):** Similarly, cancer cells may also have receptors for the hormone progesterone. The presence of progesterone receptors indicates that the cancer cells may respond to progesterone, another hormone that can promote cell growth.

The status of hormone receptors in breast cancer is important for treatment decisions. Hormone receptor-positive breast cancers are often treated with hormone therapy, which aims to block the effects of estrogen or progesterone on cancer cells. This can be achieved through medications like tamoxifen or aromatase inhibitors.

Knowing the hormone receptor status helps oncologists tailor treatment plans to target the specific characteristics of the cancer. Patients with hormone receptor-positive breast cancer generally have a better prognosis compared to those with hormone receptor-negative tumors, as hormone therapy has proven to be effective in slowing or halting the growth of these cancers.