A study of snuff carcinogenesis.

Dry snuff contains high levels of tobacco-specific N-nitrosamines (TSNA); their concentrations exceed by more than 100 times the quantities of nitrosamines found in any other consumer product. The concentrations of TSNA are similar in dry snuff and in the more popular moist snuff. In addition to the four TSNA identified earlier [N'-nitrosonornicotine (NNN), 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK), N'-nitrosoanatabine (NAT) and N'-nitrosoanabasine (NAB)], two new nitrosamines were detected in snuff, namely 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanol (NNAl; 0.07-0.15 ppm) and 4-(N-nitrosomethylamino)-4-(3-pyridyl)-1-butanol (iso-NNAl; 0.06-1.1 ppm). After oral swabbing with a mixture of NNN and NNK, rats developed tumours of the oral cavity and lung, showing that these TSNA are not only organ-specific carcinogens but can also induce local tumours. After swabbing an extract of snuff containing the same concentrations of NNN and NNK, significantly fewer tumours were induced in the oral cavity and lung, indicating inhibition of the tumorigenic activity of the TSNA by other snuff constituents.