Given that overexpression of human epidermal growth factor receptor 2 (HER2) is well known to drive carcinogenesis in several different solid tumors (such as breast cancer, gastric cancer, CRC, and NSCLC) and that it is also found in around 80% of GBMs [118], HER2 CAR-T cell therapy has been extensively explored, with mixed clinical results and concerns about toxicities due to off-target effects [119]. Here, ERBB2 is linked to breast cancer.