BREAST CANCER

1. Context

2. What is Hormone Therapy?

• Hormone therapy (also called hormonal therapy, hormone treatment, or endocrine therapy) slows or stops the growth of hormone-sensitive tumors by blocking the body's ability to produce hormones or by interfering with the effects of hormones on breast cancer cells.
• Tumors that are hormone insensitive do not have hormone receptors and do not respond to hormone therapy.
• Hormone therapy for breast cancer should not be confused with menopausal hormone therapy (MHT) - treatment with estrogen alone or in combination with progesterone to help relieve symptoms of menopause.
• These two types of therapy produce opposite effects: hormone therapy for breast cancer blocks the growth of HR-positive breast cancer, whereas MHT can stimulate the growth of HR-positive breast cancer. For this reason, when a woman taking MHT is diagnosed with HR-positive breast cancer she is usually asked to stop that therapy.

3. Hormone therapy for breast cancer

• Some types of breast cancer are affected by hormones, like estrogen and progesterone. Breast cancer cells have receptors (proteins) that attach to estrogen and progesterone, which help them grow.
• Most types of hormone therapy either lower estrogen levels in the body or stop estrogen from helping breast cancer cells grow. Hormone therapy can reach cancer cells almost anywhere in the body and not just in the breast.
• It's recommended for women with tumors that are hormone receptor-positive. It does not help women whose tumors don't have hormone receptors (these tumors are called hormone receptor-negative).
• Hormone therapy is often used after surgery (as adjuvant therapy) to help reduce the risk of cancer coming back.
• Sometimes it is started before surgery (as neoadjuvant therapy). It is usually taken for at least 5 years.

4. Molecular mechanism of Hormone therapy

• Hormone therapy targets hormone receptors in breast cancer cells to slow/stop the growth of cancer.
• A 2018 study found two genes being produced in excess amounts, while the expression of a few microRNAs was reduced when breast cancer cell lines were treated with progesterone.
• Through the action of SGK1 and two other genes, and two microRNAs, the ability of the breast cancer cells to migrate and invade is reduced.
• Current work focused on the role of non-coding genes;non-coding genes do not produce any proteins but regulate the expression of other genes.
• Treatment of breast cancer cells with progesterone results in the down-regulation of a long non-coding linc RNA called DSCAM-AS1. This results in elevated levels of a microRNA known as miR-130a.
• As with progesterone therapy, reducing the expression of DSCAM-AS 1 slowed down the ability of breast cancer cells to invade and migrate.
• The detection of DSCAM-1 in blood or tumor tissue is likely to provide information about the aggressiveness of cancer and prognosis.
• The researchers hypothesize that cancer cells might be resistant to hormone therapy when the microRNA miR-130a binds to the estrogen receptors.

For Prelims