title: Aging, environmental influences, and photocarcinogenesis.
abstract: Repeated exposure of human skin to solar ultraviolet radiation (UVR) over a period of many years is responsible for the induction of most nonmelanoma skin cancers in man. The tumors are progressively more common in chronologically older people. Is this fact purely a function of adequate dose accumulation and development time, or is tumor expression influenced by "physiological age"? The answer to this question influences risk estimates of the results of atmosphere modification. Data from animal studies indicate that the tumor incidence is affected by dose-delivery factors and not just by the accumulated lifetime dose. In addition, young mice are more prone to tumor induction by a given UVR dose than are older animals. Because the quanlity and quantity of the stimulus (UVR) can be readily manipulated and accurately described, studies on photocarcinogenesis offer distinct possibilities for untangling some of the interactive variables in the aging process.
mesh_terms: D000368:Aged; D000375:Aging; D000818:Animals; D002280:Basal Cell Carcinoma / Q000209:etiology; D002294:Carcinoma, Squamous Cell / Q000209:etiology; D004307:Dose-Response Relationship, Radiation; D004777:Environment; D006801:Humans; D051379:Mice; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000209:etiology*; D012878:Skin Neoplasms / Q000209:etiology*; D013472:Sunlight; D014466:Ultraviolet Rays / Q000009:adverse effects