Tumor Promoting Activity of Cigarette Smoke on the Upper Airway Epithelium in Hamsters

Four groups of Syrian Golden hamsters were treated as follows: Group I was exposed to cigarette smoke (Hamburg type II machine) after intralaryngeal initia tion of total 240μg 7, 12-dimethylbenzanthracene (DMBA); Group II was treated as vehicle alone controls followed by smoke exposure: Group III was exposed to cigarette smoke without the initial dose of initiation. Group IV received DMBA and sham moked. The animals received a combination of DMBA and smoke exposure developed after 52 weeks various neoplastic changes including 4 epidermoid carcinomas in a significantly higher incidence and earlier than other control groups. These findings lead to the conclusion that promoting agents or cocarcinogens have an important function in cigarette smoke carcinogenesis in major respiratory tract.