TP53 and cancer: Because p53 can induce tumor cell death and p53 function is lost in most cancers, the most active avenue is to identify small molecules that will allow the reactivation of p53 or block MDM2, such as Nutlin-3 which blocks the interaction of p53/MDM2, and HLI98 which directly targets the ubiquitin-ligase activity of MDM2 (Vousden and Lane, 2007).