Skin Carcinogenesis laboratory animals

In their lengthy 1964 review of tobacco carcinogenesis, Wynder and Hoffmann (4319) stated that no one could deny that tobacco products were tumorigenic even though no single component in tobacco smoke could by itself or jointly with other components account for the observed tumorigenic activity of such tobacco products to the skin of laboratory animals ... 

Until the mid-1970s, most studies in chemical carcinogenesis were experimental, i.e., suspect materials were placed continuously on the skin or in the diets of laboratory animals who were then observed to see if any neoplasms developed. While such work was invaluable in identifying materials which should be removed from the environment, or otherwise avoided, it did not provide any major understanding of the basis of chemical carcinogenesis. Indeed, many of the dermal tests merely indicated allergic reactions and many of the dietary tests showed that some animals thrived on trace additives. 

Complete Carcinogenesis Studies. Studies in laboratory animals have demonstrated the ability of benz[a]anthracene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[a]pyrene, chrysene, dibenz[a,h,]anthracene, and indeno[1,2,3-c,d]pyrene to induce skin tumors (i.e., they are complete carcinogens) following intermediate dermal exposure. Anthracene, fluoranthene, fluorene, phenanthrene, and pyrene do not act as complete carcinogens. The data supporting these conclusions are discussed below by chemical. Only those studies considered adequate and reliable with respect to study design and adequacy of reporting are presented in Table 2-3. 

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