p53 induced growth arrest versus apoptosis and its modulation by survival cytokines.

The p53 tumor suppressor gene encodes for a transcription factor that plays a seminal role in the response of mammalian cells to physiological and environmental stress. p53 has been implicated as a major mediator of cell cycle arrest and/or apoptosis in the response of mammalian cells to stress stimuli. It appears that several determinants, including cell type, the presence or absence of survival factors in the external environment, the extent of DNA damage, the level of p53 and post-translational modifications, are involved in the choice between cell cycle arrest and apoptosis. Ongoing work on the biological functions of the p53 tumor suppressor in different cell types and under various physiological conditions will help to unravel the complex nature of molecular circuits that orchestrate the biological response to p53 activation.