FLT3 and leukemia: Since FLT3 ligand promotes the dimerization and phosphorylation of FLT3 within 5–15 min and subsequently activates several pathways involved in cell survival and proliferation, such as RAS/RAF/Erk, PI3K/Akt/mTOR, and JAK/STAT [34], it was supposed that FLT3L expressed by CAR-T cells might promote dimerization and activation of FLT3 in FLT3-WT cells, and activation of the signal transduction cascades in FLT3 wild-type leukemia cells may promote their survival and relieve damage.