Carcinogenic N-
nitrosamine contamination in certain drugs has recently caused great concern and the attention of regulatory agencies. These
carcinogens-widely detectable in relatively low levels in food, water,
cosmetics, and drugs-are well-established and powerful animal
carcinogens. The electrophiles resulting from the
cytochrome P450-mediated metabolism of N-
nitrosamines can readily react with
DNA and form covalent addition products (
DNA adducts) that play a central role in
carcinogenesis if not repaired. In this review, we aim to provide a comprehensive and updated review of progress on the metabolic activation and
DNA interactions of 10 carcinogenic N-
nitrosamines to which humans are commonly exposed. Certain
DNA adducts such as
O6-methylguanine with established miscoding properties play central roles in the
cancer induction process, whereas others have been linked to the high incidence of certain types of
cancers. We hope the data summarized here will help researchers gain a better understanding of the bioactivation and
DNA interactions of these 10 carcinogenic N-
nitrosamines and facilitate further research on their toxicologic and carcinogenic properties.