MDM4 and cancer: Reactivation of p53 by blocking p53-MDM2/MDMX(MDM4) interaction is one of the most promising approaches for cancer therapy, and MDM2 inhibitors (such as AMG232 or milademetan) and the dual inhibitors of MDM2/MDMX (such as ALRN6924) are currently undergoing clinical evaluation [9,10].