A study of betel quid carcinogenesis. IV. Analysis of the saliva of betel chewers: a preliminary report.

Betel quid chewing is strongly associated with cancer of the oral cavity, especially when tobacco is added to the quid. It is our working hypothesis that, during chewing, Areca-derived N-nitrosamines are formed and, in the presence of tobacco, Nicotiana-specific N-nitrosamines are formed as well and further that these agents may contribute to the high risk of oral cancer in betel-quid chewers. This preliminary report presents our finding of N-nitrosoguvacoline in the saliva of betel-quid chewers (2.2-350 ppb). When the quid contains tobacco, the tobacco-specific N-nitrosamines, N'-nitrosonornicotine (1.2-38.3 ppb), N'-nitrosoanatabine (3.2-39.5 ppb), and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (1.0-2.3 ppb) are also found in the saliva.