ERBB2 and colorectal carcinoma: In the current study, the specific activity of HER2 CAR-T cells against HER2+ tumors was evaluated by incubating the HER2 CAR-T cells with established human CRC cells (DLD-1) at an effector-to-target (E/T) ratio of 1:1, 5:1, and 10:1 in the absence of exogenous cytokines (Fig. 3C).