MMRi64, for example, disrupts the MDMX-MDM2 RING-RING interaction, which leads to inhibition of MDMX-induced MDM2 E3 ligase activity toward p53, resulting in activation of the apoptotic arm of the p53 pathway in leukaemia/lymphoma cells [43,44] (Table 2). This evidence concerns the gene MDM4 and leukemia.