Rapid activation of the p53 response following genotoxic insults is imperative to efficiently switch on tumor-suppressive functions of p53.2 Compared to the initiation of p53 gene expression, which takes relatively long to robustly increase p53 protein levels, inhibition of MDM2 is very fast and provides a very efficient means to enhance p53 levels. This evidence concerns the gene TP53 and neoplasm.