It is easy to understand that the constitutive activation of ABL in BCR-ABL+ ALL is inhibited by nilotinib, which leads to the dissociation of MDM2 from the MDM2-MDM4 complex, resulting in ubiquitination and degradation; however, we also detected an inhibition of MDM2 by nilotinib in the BCR-ABL– ALL. Here, MDM4 is linked to acute lymphoblastic leukemia.