NNK is a nicotine-derived nitrosamine found in tobacco and is used in research to understand the cancer-causing potential of nitrosamines. Researchers exposed rats to different doses of NNK for 28 days and then examined genetic mutations in lung and liver tissue.
The lung responded to lower doses than the liver, indicating greater sensitivity to NNK-related mutagenic effects. The types of mutations also differed between the two organs. These results come from an animal model and should not be treated as a direct measure of human cancer risk.