MDM4 and cancer: Together with the radioresistant lymphoma phenotype of non-degradable MdmX mutant mice,41 these findings point MdmX as another valid drug target for p53-based cancer therapy.13 Using an elegant mouse model, Even's group demonstrated that MdmX is a better drug target than Mdm2 in lymphoma.42 To overcome MdmX-mediated resistance, dual inhibitors that target both Mdm2–p53 and MdmX–p53 interfaces were also explored.