To confirm the decrease in mitochondrial ROS levels is important to the chemoresistance of T-ALL cells, we treated mono-cultured cells with MitoTEMPO (50 μM; a specific mitochondrial ROS scavenger) for 6 h and observed the decreased mitochondrial ROS levels (Supplementary Figure 4D) and reduced percentage of Annexin V-positive cells (Figures 2e and f) in the presence of chemotherapeutic drugs. This evidence concerns the gene ANXA5 and acute lymphoblastic leukemia.