Human Epidermal Growth Factor Receptor 2 (HER2)

HER2, or Human Epidermal Growth Factor Receptor 2, is a protein found on the surface of some cells, including certain breast cancer cells. It helps regulate cell growth and repair. In some cancers, the HER2 gene is overly active, leading to too many HER2 proteins on the cell surface. This can cause cells to grow and divide uncontrollably. Testing for HER2 helps determine the best treatment options, as HER2-positive cancers may respond well to targeted therapies that block this protein, controlling the disease more effectively.