Name the subtype of breast cancer that hormonal therapy is used to treat. Briefly explain how hormonal therapy works.

The subtype of breast cancer that hormonal therapy is used to treat is hormone receptor-positive breast cancer. This type of cancer has receptors for the hormones estrogen and/or progesterone, which can promote the growth of cancer cells.

Hormonal therapy works by blocking the cancer cells' ability to receive these hormones, thereby slowing or stopping their growth. There are several ways this can be achieved:

1. Medications like Tamoxifen can be used to block the hormone receptors on the cancer cells, preventing them from receiving the hormones they need to grow.

2. Aromatase inhibitors can be used to reduce the amount of estrogen produced by the body. These are often used in postmenopausal women, as most of their estrogen is produced outside of the ovaries.

3. Luteinizing hormone-releasing hormone (LHRH) agonists can be used to stop the ovaries from producing hormones. This is often used in premenopausal women.

4. Sometimes, surgery to remove the ovaries (oophorectomy) is performed to stop hormone production in premenopausal women.

In all these ways, hormonal therapy aims to halt the growth of hormone receptor-positive breast cancer by depriving the cancer cells of the hormones they need to proliferate.