The p53 gene has been the subject of a great deal of scientific attention in past years; it appears to important in many fundamental biochemical processes relating to aging and cancer. As is usual in biochemistry, the closer you look, the more complex things turn out to be: "the p53 gene, the most frequently inactivated gene in human cancer, does not produce only one unique p53 protein as previously thought, but at least six different p53 proteins (isoforms). ... This suggests that, in [some] tumours, p53 activity is being lost by altered isoform expression, rather than by mutation of the p53 gene itself." Meanwhile, research into the mechanisms of Progeria suggests that "hyperactivation of the tumour suppressor p53 may cause accelerated ageing."
Link: http://www.innovations-report.de/html/berichte/biowissenschaften_chemie/bericht-49254.html