3To whom correspondence should be addressed:

D ow nloaded from 2 Previous studies demonstrated that repeated application of smoke condensate from tobacco-burning reference cigarettes to chemically initiated SENCAR mouse skin promotes the development of tumors in a statistically significant and dose-dependent manner, while condensate from prototype cigarettes that primarily heat tobacco promotes statistically fewer tumors. Based on the recognized correlation between sustained, potentiated epidermal hyperplasia and tumor promotion, studies were conducted to examine the utility of selected short-term analyses for discriminating between condensates exhibiting significantly different promotion activities. In vitro analyses assessing the potential for inducing cytotoxicity (ATP bioluminescence) or free radical production (cytochrome c reduction, salicylate trapping) demonstrated significant reductions when comparing condensate collected from prototyp