N'-Nitrosonornicotine

N'-Nitrosonornicotine is a tobacco-specific N-nitrosamine and carcinogen that has been found in unburned tobacco and cigarette smoke.1It induces the formation of DNA adducts in isolated rat nasal mucosa and esophagus. N'-Nitrosonornicotine induces tumor formation in rat esophagus and nasal cavity, mouse lung, forestomach, and trachea, and hamster trachea and forebrain. Urinary levels of N'-nitrosonornicotine are positively correlated with the risk of esophageal cancer in smokers.2