To explore the clinical significance of enhancement of p53 activation in treatment of TKI-resistant leukemias, we examined the effects of nutlin-3 in cells expressing BCR/ABL with the T315I mutation, which confers resistance not only to the first generation TKI imatinib but also to the second-generation TKIs nilotinib and dasatinib [13, 14]. Here, BCR is linked to leukemia.