Estrogen, Progesterone and HER-2 Receptors
Thie article describes Estrogen, Progesterone and HER-2. The descriptions are courtesy of the American Cancer Society.
Estrogen is a female sex hormone produced mostly by the ovaries, and in smaller amounts by the adrenal cortex.
In women, levels of estrogen fluctuate on nature's carefully designed schedule, regulating the development of secondary sex characteristics, including breasts; regulating the monthly cycle of menstruation; and preparing the body for fertilization and reproduction.
In breast cancer, estrogen may promote the growth of cancer cells.
An estrogen receptor assay is a laboratory test done on a sample of the cancer in order to see whether estrogen receptors are present. The growth of normal breast cells and some breast cancers is stimulated by estrogen. Estrogen receptors are molecules that function as cells' "welcome mat" for estrogen circulating in the blood. Breast cancer cells without these receptors (called estrogen-receptor negative or ER negative) are unlikely to respond to hormonal therapy. Estrogen-receptor positive cancers are more likely to respond to hormonal therapy.
Progesterone is a female sex hormone released by the ovaries during every menstrual cycle to prepare the uterus for pregnancy and the breasts for milk production (lactation).
A progesterone receptor assay is a laboratory test done on a sample of the breast cancer that shows whether the cancer depends on progesterone for growth. Progesterone and estrogen receptor tests provide more complete information to help decide the best cancer treatment for the patient.
HER-2 gene (sometimes referred to as HER2/neu) is an oncoprotein which is present in very small amounts on the outer surface of normal breast cells. About 25% to 30% of breast cancers have too much of this protein. Some other types of cancer also have too much HER2 protein.
HER stimulates cell growth, and breast cancers that produce too much of this protein tend to be more aggressive.
A monoclonal antibody used to treat this type of breast cancer attaches to the HER2 protein, slow the growth of the breast cancer cells, and may also stimulate the immune system to more effectively attack the cancer.