1977 Volume 68 Issue 3 Pages 343-352
Squamous cell carcinomas were readily induced in the lung of C57BL/6 mice by repeated intratracheal instillations of benzo[a]pyrene with charcoal powder suspended in saline solution. Intratracheal instillations were performed once a week for 8 weeks, and the observation period of the experiment was 40 weeks. Some of the tumors were highly keratinized and others were moderately keratinized squamous cell carcinomas. At a later period of observation, poorly differentiated squamous cell carcinomas were found. Invasion into blood vessels was occasionally seen but metastasis to regional lymph nodes or distant metastasis was not found. One tumor from the mouse killed on the 280th day was successfully transplanted subcutaneously into C57BL/6 mice. This mouse, killed on the 84th day after the first transplantation, had a pulmonary metastasis.
