This balance is critical for tumour suppression by p53 and has a considerable impact on the magnitude of p53 activation in response to cellular stresses.32, 33, 34 Inhibition of the proteasomal degradation of p53 and enhanced degradation of Mdm2 are involved in p53 activation in response to stress signals.35, 36 Interventions that stabilize both p53 and Mdm2, including inhibition of the proteolytic activity of the proteasome, can lead to the accumulation of sufficient Mdm2 to repress the transcriptional activity of p53.30, 35, 37. This evidence concerns the gene TP53 and neoplasm.