Since p53 is a tumor suppressor that can influence the rate of aging and modulate regeneration in both mammals and Drosophila imaginal discs [9,29,30], we reasoned that a long living animal such as the axolotl may teach us lessons on how the p53 system is properly modulated to ensure a long life span, tissue regenerative capacity and efficient tumor suppression. This evidence concerns the gene TP53 and regulation of cell cycle.