Use of Druckrey analysis to quantitatively evaluate the chemopreventive efficacy of N-difluoromethylornithine (DFMO), a prototype proliferation inhibitor

Abstract

Druckrey analysis of the results of skin painting TG.AC transgenic mice with three different doses of benzo[a]pyrene was used to obtain quantitative estimates of the in vivo cancer chemopreventive efficacy of N-difluoromethylornithine. The percent decrease in mean rate of subvisible tumor development during the tumor latent period produced by 2000 ppm and 4000 ppm DFMO in the diet was 39% and 50%, respectively. Druckrey analysis was also successfully applied to transformations of published data on human cigarette smokers. The time before onset of lung cancer in 2% of smokers was prolonged 17 weeks for every cigarette per day not smoked. The Druckrey model, of substantiated validity because of the results in human smokers, provides a rapid quantitative screening method applicable to large numbers of candidate chemopreventive agents.