The importance of its role is exemplified by the facts that p53 activity is ubiquitously lost in human cancer either by p53 protein inactivation or by p53 gene mutation (for a review, see Iwakuma and Lozano, 2007; Lozano, 2007; Petitjean et al, 2007a; Vousden and Lane, 2007). The gene discussed is TP53; the disease is cancer.