Lung Tumors in Mice: Application to Carcinogenesis Bioassay

This chapter provides information on lung tumors in mice, with emphasis on the use of mouse lung for quantitative investigations in carcinogenesis, especially bioassay of chemicals for carcinogenic activity. The lung-tumor response in strain A mice is easily and clearly positive to all major types of chemical carcinogens. Strain A mice are the most susceptible to a wide variety of carcinogens, in terms of the earlier appearance and greater multiplicity of tumors. The lung-tumor response in strain A mice is easily and clearly positive to all major types of chemical carcinogens. Estrogenic and other steroid hormones, with the targets of endocrine-regulated tissues, are an exception. The lung tumor of the mouse has demonstrated its ability to pick up undetected, unpredicted neoplastic responses such as to urethane and to isoniazid. The carcinogens picked up by the lung tumor system have been shown to be carcinogenic for other tissues and in other species of animals. The mouse lung tumor is a reproducible, stable, and rapid biological model for a wide variety of quantitative investigations in carcinogenesis. It provides a three-dimensional lattice of the lung in which a known, identifiable subpopulation of cells—the type 2 alveolar pneumocytes—can be accelerated into conversion into neoplasms.