Chemoprevention of basal cell carcinomas in the ptc1+/- mouse--green and black tea

Skin cancers are a rising menace as their incidence increases, attributed in part to increasing ultraviolet radiation exposure. This increasing problem has stimulated efforts to devise useful preventive approaches. The uncertain efficacy of exhortations to avoid sun exposure and to use protective clothing and sunscreens to reduce damage when exposed argue for the development of an oral chemopreventive agent. Bickers and others have studied the effects and mechanisms of tea and of its putative active components on inhibition of skin cancer in experimental models. To continue this work, we have studied the effects of oral green tea and black tea on a new model of ultraviolet-induced skin carcinogenesis - the development of basal cell carcinomas in ptc1+/- mice. To our surprise, we have found that tea preparations which others have used to prevent squamous cell carcinoma formation in mice fail to inhibit basal cell carcinogenesis in our model, suggesting that prevention of this cancer may require special, tumor-specific approaches.