WST cytotoxic assay results showed that nilotinib exhibited very strong cytotoxic effects on the BCR-ABL+ ALL cell line SUP-B15, which overexpresses MDM2 (Fig. 4A); while EU-6 cells with lower expression of MDM2 had relatively low sensitivity to nilotinib (p<0.05); and EU-5 cells with no expression of MDM2 had much lower sensitivity (p<0.01), when compared with SUP-B15. This evidence concerns the gene MDM2 and acute lymphoblastic leukemia.