Also, Itoshima et al. (2000), observed that mutant form of p53 was also stabilized by ectopic ARF increased expression, consistent with another report where p53 mutated can also be bonded to Mdm2 (Haupt et al., 1997); however, mutant-p53 transcriptional activity is obliterated and the existence of an intact autoregulatory loop between ARF, Mdm2, and p53 is needed to observe full regulatory pathway responses, particularly, a response that leads to apoptosis in cancer cells. This evidence concerns the gene TP53 and cancer.