In contrast, no significant changes in cell viability were observed in p53-null chronic myeloid leukemia (CML) cell line K562 (Figure 2C) and in Ph− p53-mutated ALL cell line REH (Figure 2D) after incubation with MDM2 inhibitor. This evidence concerns the gene TP53 and chronic myelogenous leukemia, BCR-ABL1 positive.