P53 is an important tumor suppressor gene that binds to the DNA and activates hundreds of genes including p21.47 However, p21 expression may be regulated independently of p53.47 Conversely, as ARO cells express high levels of mutant p53 protein,48 suggesting that the reduction in the level of p53 protein expression might imply a positive outcome. This evidence concerns the gene TP53 and neoplasm.