In another solid tumor model, competitive experiments further confirmed that EGFR-BBζ + CD2 CAR-T cells presented greater expansion potential than did EGFR-BBζ CAR-T cells, as evidenced by a greater proportion of CAR-T cells in the peripheral blood and an increased number of CAR-T cells infiltrating the tumor tissue (Fig. 5G). This evidence concerns the gene CD2 and neoplasm.