p53 (also known as protein 53 or tumor protein 53), is a transcription factor which in humans is encoded by the TP53 gene. p53 is important in multicellular organisms, where it regulates the cell cycle and thus functions as a tumor suppressor that is involved in preventing cancer. As such, p53 has been described as "the guardian of the genome," "the guardian angel gene," and the "master watchman," referring to its role in conserving stability by preventing genome mutation. f13 a90 17000718 PubMed p53-independent induction of rat hepatic Mdm2 following administration of phenobarbital and pregnenolone 16alpha-carbonitrile. Toxicol Sci 2006 Nelson DM Bhaskaran V Foster WR Lehman-McKeeman LD 19043449 PubMed The genetics of the p53 pathway, apoptosis and cancer therapy. Nat Rev Drug Discov 2008 Vazquez A Bond EE Levine AJ Bond GL p53 signaling pathway PW:0000718 Pathway Ontology