[Precancerous and cancerous lesions of the esophagus and forestomach in mice with skin exposure to a heavy catalytic gas oil].

Painting with heavy catalytic gas oil was followed by skin tumor development in 97 (84.3%) mice: benign lesions--21 and carcinoma--76 cases. Pathologic changes in the upper part of the digestive tract were found in 55 out of 106 mice (51.9%): precancerous lesions (leukoplakia, dysplasia and papilloma) in 54 cases and cancer in one animal. Frequency of development of papilloma in the cardia was 27 times that in the esophagus. Multicentric growth was typical of precancerous lesions. Papilloma of the cardia was found in one control animal. Resorptive as well as direct action of gas oil seem to have been the causative factors of the development of precancerous and neoplastic lesions of the upper part of the gastrointestinal tract. The agent found its way into the digestive tract as animals licked each other in the course of the experiments.