TUMOR-PROMOTING ACTIVITY OF EXTRACTS OF UNBURNED TOBACCO.

Both an aqueous Balpha(OH)(2) extract and an acetone-benzene extract of unburned cigarette tobacco produced skin tumors when painted on mice previously treated with 125 microg of7,12-dimethylbenz[a]anthracene. The extract from as little as 0.5 cigarette per day was effective. The data are of interest in connection with epidemiological evidence that tobacco chewing is a cause of oral cancer. The data also suggest that tumor-promoting agents in cigarette smokemay have their source in the unburned tobacco