NFE2L2 and leukemia: According to our previous experiments, overexpression of Nrf2 in MSCs promoted leukemia cell invasion and migration, we successfully constructed B-ALL-PDX mouse models by injecting RS4; 11 (n = 5) and a mixture of RS4; 11 with MSCs/MSCs-EV/MSCs-LV-Nrf2 (4:1) (n = 5) using tail vein injection.