Cigarette-smoke condensate, usually combined with a solvent such as acetone, reportedly produces various changes when applied to animal tissues. These changes cover a wide range from mild hyperplasia to gross, metastasizing cancer. Tissues so far studied include skin, oral mucosa, bronchial mucosa, epithelium of bladder, and uterine cervix.3,7,8,10,24 Most studies have been in mice, a few in hamsters, rabbits, and rats. Histologic cancer from the condensate has been reported in skin, bladder, cervix, and mouth.4,7,8,24
Of the 18 or more polycyclic hydrocarbons22 identified in the condensate, 8 are reported to be carcinogenic for animals.25 While some investigators emphasize that concentrations of carcinogenic hydrocarbons in the condensate (predominately benzo[a]pyrene) are not sufficient to justify rating cigarettes as a major factor in human cancer,9 others feel that the complexity of the condensate, varying with different conditions of combustion in its production and containing multiple carcinogens