In the HER2.High group, mice treated with HER2 CAR-T cells exhibited considerably decreased tumor size as compared with the NT-T cells, while subtle changes in the HER2.Low group (Fig. 5B), suggesting that HER2 CAR-T cells effectively infiltrated into tumor tissues and selectively eliminated HER2+ CRC cells, implying the excellent therapeutic effect of HER2 CAR-T cells on HER2+ CRC. The gene discussed is ERBB2; the disease is neoplasm.