MDM2 and cancer: A recent study has shown that compared with VHL-based PROTACs, MDM2-based PROTACs might offer a synergistic anti-proliferative activity to cancer cells (Hines et al., 2019), in part due to the degradation of target protein bromodomain-containing protein 4 (BRD4), as well as the stabilization and accumulation of the tumor suppressor p53, a well-characterized endo-substrate of MDM2 (Chene, 2003).