ITGB1 and leukemia: The transwell chamber test revealed that compared with the leukemia cells in the control group and the EV group co-culturing with TGF-β conditioned MSCs, the migration and invasion of the leukemia cells in the co-culture system of Nalm-6/RS4;11-LV-ITGB1 and TGF-β conditioned MSCs group were significantly enhanced (P < 0.05; Figures 8C,D).