Mad dogs, Englishmen and apoptosis: the role of cell death in UV-induced skin cancer.

Apoptosis plays a critical role in the development and progression of ultraviolet-induced skin cancers. In particular, Fas and Fas ligand (FasL) interactions are known to control the development of "sunburn cells" or apoptotic keratinocytes in the UV-exposed epidermis. In the absence of functional Fas/FasL signaling, UV-induced apoptosis is diminished and mutations rapidly accumulate. UV-induced suppression of host immunity, a process regulating skin cancer outgrowth, is also controlled through Fas/FasL interactions. Other death receptors, such as the receptor for tumor necrosis factor, may also contribute to UV-induced carcinogenesis and progression. Understanding the involvement of cell death in cancers caused by exposure to sunlight may provide novel approaches for prevention and therapy of these ever-increasing malignancies.