Human epidermal growth factor receptor 2 (HER-2/neu receptor) is a molecule present in small amounts on the surface of certain types of cells, such as breast cells and ovarian cells. The HER-2/neu receptor binds to human epidermal growth factor (hEGF), a molecule that can stimulate the multiplication of the cells.
Some types of breast cancer cells and some types of ovarian cancer cells produce abnormally high levels (called over-expression) of the HER-2/neu receptors on their surfaces.
Certain patients with breast cancer that over-expresses HER-2/neu receptors may be treated with the biological medication, Herceptin (generic name trastuzumab, which is a special type of (monoclonal) antibody. As Herceptin can block the binding between the HER-2/neu receptor and hEGF, Herceptin treatment can slow the multiplication of breast cancer cells that over-express HER-2/neu receptors. Also, Herceptin bound to the HER-2/neu receptor can help the immune system to try to rid the body of the cancer cells.