Especially, FLT3L CAR-T cells could promote the phosphorylation of ERK1/2 in FLT3-WT cells but not FLT3-ITD cells, and it had no inhibitory effects on CD34+ stem cell colony formation, which indicated its stronger cytotoxic effect on FLT3-ITD leukemia cells and potential in protection of normal HPSCs. Here, MAPK3 is linked to leukemia.