Using ALL blast mitochondria from 16 samples consisting of primary ALL cells or patient-derived xenografts, we found a statistically significant correlation between mitochondrial sensitivity to BAD BH3 peptide (indicating BCL-2, BCL-XL, or BCL-W dependence) and cell viability determined by half-maximal inhibitory concentration (IC50) values of ABT-199 (Figure 5B; Table S2). This evidence concerns the gene BCL2 and acute lymphoblastic leukemia.