Question: what is the difference between her2 positive and her2 negative?
Answer: When a breast cell has abnormally high levels of the HER2 gene or the HER2 protein, it is called HER2- positive. The cancer is called HER2-negative when it does not have high levels of the HER2 gene or the HER2 protein. Most patients with metastatic breast cancer have HER2-negative breast cancer.