Then, we performed different assays to verify the specific cytotoxicity of Nectin4 CAR-T cells in vitro through the xCELLigence RTCA label-free technology and found that the co-incubation of Nectin4 CAR-T cells with ABC-1, HT1376, and MDA-MB-453 cells could cause an immediate and time-dependent decrease in cell index within 4 h, respectively, but not CD19 CAR-T cells (Figure 3B), demonstrating that Nectin4 CAR-T cells efficiently executed specific cytolysis against Nectin4-positive tumor cells and exhibited better cytotoxicity at the gradually increasing appropriate ratio of Effect/Target. The gene discussed is CD19; the disease is neoplasm.