Immunohistochemistry (IHC) is a common diagnostic tool used in breast pathology to help determine the type of breast cancer a patient has, as well as the best course of treatment. It is a technique that uses antibodies specific for certain proteins to detect the presence of those proteins in breast cancer cells. In breast pathology, IHC is typically used to examine the expression of hormone receptors (estrogen and progesterone) and human epidermal growth factor receptor 2 (HER2) in breast cancer cells.
By analyzing these markers, doctors can better determine the prognosis and the appropriate course of treatment for the patient. For example, patients whose breast cancer cells express hormone receptors may be candidates for hormone therapy, while those with HER2-positive breast cancer might benefit from targeted therapies such as trastuzumab (Herceptin).