Epidemiological and experimental studies on tobacco-related oral cancer in India.
Both population-based incidence rates and relative frequencies of oral and pharyngeal cancer seen in six major cancer hospitals in India indicate that these forms of cancer occur frequently. Case-control studies reveal that these cancers are associated with tobacco chewing and bidi smoking. Experimental studies on a variety of chewing tobacco used commonly in western India revealed that it contains N-nitrosonornicotine and 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone in microgram quantities per gram of tobacco. A crude alcoholic extract of tobacco containing these nitrosamines was mutagenic in histidine-deficient Salmonella typhimurium strain TA98 in the presence of a 9000 X g supernatant fraction. Gavage feeding of this extract for 7, 15 and 30 days induced activity of mixed-function oxygenases. Feeding of the tobacco extract by gavage or in diets induced lung and liver tumours in Swiss mice.
D000818:Animals; D002273:Carcinogens; D005260:Female; D006801:Humans; D007194:India; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009062:Mouth Neoplasms / Q000453:epidemiology / Q000209:etiology*; D009152:Mutagenicity Tests; D009153:Mutagens; D009602:Nitrosamines / Q000633:toxicity; D010610:Pharyngeal Neoplasms / Q000453:epidemiology / Q000209:etiology*; D010947:Plants, Toxic; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics; D012907:Smoking; D014026:Nicotiana
D002273:Carcinogens; D009153:Mutagens; D009602:Nitrosamines; C016583:4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone; C008655:N'-nitrosonornicotine