However, Ghassemi et al., in 2018, reported that CAR-T cells targeting CD19 (CART19) expanded for 3–5 days proliferated more and showed greater cytotoxic ability in vitro, as well as in a murine xenograft model of ALL, showing that the antileukemic activity inversely correlated with the ex vivo culture time. This evidence concerns the gene CD19 and acute lymphoblastic leukemia.