TP53 and cancer: The tumor suppressor gene functions include regulation of the cell cycle and the cellular response to DNA damage, initiation of DNA repair and replication, induction of apoptosis and promotion of cell differentiation.10 Inactivation of the p53 tumor suppressor gene is correlated to a critical step in the development of many human cancers.11 It may result from a number of events including mutation of the p53 gene (with or without associated allelic deletions) and binding of the p53 to cellular or viral proteins.