Counts of FAP− U251 cells were reduced significantly only when co‐cultured with both U87 cells and FAP‐CAR‐T cells (Figure 6a), suggesting that antigen‐negative U251 tumor cells are also susceptible to bystander killing from FAP‐CAR‐T cells, similar to our earlier observations using GNS cells. This evidence concerns the gene FAP and neoplasm.