[Experimental lung carcinogenesis. Areas of application and perspectives]

Although they have been described in several species, lung cancers are rare cancers, occurring in old age. For this reason, experimental lung carcinogenesis is practically limited to short-living rodents, rats being the most frequently used; other species have not been shown to provide improved models for extrapolation to man although they may be useful for specific toxicokinetics of some xenobiotics. The aim of experimental lung carcinogenesis is to detect putative airborne carcinogens which may cause cancer in man. Compared to man, for similar cumulated exposure, there is a general trend for a given ultimate carcinogen to result in a high rate of tumor induction in rodents; this is due to deposition and clearance patterns, together with the distal location of tumors. A weak response in rats exposed to tobacco smoke only can be easily explained by basic toxicokinetics; rats exhibit a strong response to the promoting effect of tobacco smoke. In vitro transformation of animal and human lung cells is expected to be a key issue for the purpose of interspecies extrapolation.