Oral Cancer Carcinogen Found in Smokeless Tobacco
(ChemotherapyAdvisor) – Smokeless tobacco products contain known carcinogens involved in the development of oral cancer, according to Stephen S Hecht, PhD, of the Masonic Cancer Center, University of Minnesota, Minneapolis, MN. This conclusion is based on an abstract entitled “DNA Binding of the Smokeless Tobacco Constituent (S)-N'-nitrosonornicotine [(S)-NNN] Predicts its Oral Cavity Carcinogenicity in Rats,” which was presented at the 244th National Meeting & Exposition of the American Chemical Society on August 22nd in Philadelphia, PA.
It is well established that chemicals found in tobacco are carcinogenic, but not much is known about similar carcinogens in smokeless tobacco products. According to the investigators of this study, smoking tobacco products, also known as chewing tobacco, contains NNN, an established esophageal carcinogen in rats. (S)-NNN, which is the predominant form of NNN, attaches to DNA in cells of oral cavity and esophagus in rats, suggesting that if humans are exposed to (S)-NNN through the consumption of smokeless tobacco, they may develop cancer.
In this study, the investigators aimed to “demonstrate the powerful carcinogenicity of (S)-NNN in the rat oral cavity.” Using this model of human oral cancer, the investigators treated rats (N=20) with (S)-NNN in their drinking water for 17 months. All of these rats developed multiple oral tumors (n=91), including malignant squamous cell carcinomas and esophageal tumors, the investigators reported.
Based on these findings, the investigators concluded that “(S)-NNN, a known strong oral cavity carcinogen in smokeless tobacco, should be removed from these products without delay.”