ERBB2 and breast cancer: In the last 2 decades, many groups have developed HER2-directed CAR-T cells for the treatment of colorectal cancer [16], breast cancer [17], gastric cancer [18], sarcoma [19], glioblastoma [20], ovarian cancer [11], osteosarcoma [21], and medulloblastoma [22] in either patients or pre-clinical models.