MDM2 and cancer: Nutlin is a selective small-molecule inhibitor of the p53-Mdm2 interaction that releases p53 from Mdm2 control, leading to accumulation of the tumour suppressor protein and activation of the P53 pathway.33, 34 Treatment of cancer cells with wild-type P53 induces cell arrest and apoptosis in vitro and suppresses the growth of human tumour xenografts in nude mice.33, 35