p53 is a tumor suppressor gene and mutation of p53 is a frequent event in s
kin cancer. The wild-type p53 encodes for a 53-kD phosphoprotein that plays
a pivotal role in regulating cell growth and cell death. The wt-p53 gene i
s also called "guardian of the genome", for its role in preventing the accu
mulation of genetic alterations, observed in cancer cells. The wild-type p5
3 protein plays a central role in the response of the cell to DNA damage. U
V, present in sunlight, is one of the most ubiquitously present DNA damage
inducing stress conditions to which skin cells are exposed. The wt-p53 prot
ein accumulates in human skin cells in vitro and in human skin in vivo upon
UV irradiation. This upregulation mounts a protective response against per
manent DNA damage through transactivation of either cell cycle arrest genes
and DNA repair genes or genes that mediate the apoptotic response. The mol
ecular events which regulate the activity of the wt-p53 protein activity ar
e only beginning to be described. (C) 2001 Elsevier Science B.V. All rights
reserved.