what is her2 negative breast cancer

HER2-negative breast cancer is a type of breast cancer where the cancer cells do not have abnormal levels of HER2 proteins. HER2 stands for human epidermal growth factor receptor 2, which is a protein found on the surface of breast cells. HER2-negative breast cancer tends to have a better outlook than HER2-positive breast cancer, which has unusually high levels of HER2 proteins and grows and spreads more quickly. Treatment options for HER2-negative breast cancer depend on whether it is hormone-positive or hormone-negative, as well as the stage of the cancer. Tests that can determine HER2 status include immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH).