MDM4 and neoplasm: Indeed, this lack of HDMX-targeting hasbeen shown to limit the therapeutic efficacy of HDM2-targeting smallmolecules in tumor cells.25,52,53 This may be a particular problem in cases of DLBCL, which have alarge array of copy number alterations that decrease p53 activityand where overexpression of HDM2 and HDMX is common.24,28