Overview:

p53 is a key regulator of cell growth and acts as a tumor suppressor gene. Wild-type p53 gene can suppress transformation of rat embryo fibroblasts in cell culture by other oncogenes such as the adenovirus E1A and Ras (1). DNA tumor viruses such as SV40 large T antigen and the adenovirus E1A plus E1B-55Kd proteins bind to p53 and inactivate its tumor suppressor activities leading to cellular transformation. Mutational inactivation of the p53 gene is detected in more than 50% of human cancers. Mutation of p53 renders cancer cells more resistant to current cancer therapies due to lack of p53-mediated apoptosis (2).

References:

1.Levine, A J. et al: Tumor suppressor genes: the p53 and retinoblastoma sensitivity genes and gene products. Biochim Biophys Acta. 1990 Jun 1;1032(1):119-36.2.Sun, Y. p53 and its downstream proteins as molecular targets of cancer. Mol Carcinog. 2006 Jun;45(6):409-15.