Both the HER2 gene and the HER2 protein
are part of normal cell
growth. They are seen in the breast cells of people who do not have cancer. But sometimes mutations, mistakes in a cell’s DNA, cause the body to make too many HER2 proteins. This can cause breast cells to grow faster than normal, which can lead to breast cancer.
Look below for more information from LBBC about HER2-positive breast cancer.