Potential genotoxicity of chronically elevated nitric oxide: A review

Several human cancers are associated with chronic bacterial, viral and parasitic infections. Nitric oxide, which is a short-lived free radical produced by many types of cells for a number of important physiological functions, is elevated in these infections. Long-term exposure to elevated NO · cells could have potential genotoxic effects on hosts. There are at least three mechanisms by which intracellular elevated NO · could exert genotoxic affects after reacting with O₂. These include formation of carcinogenic N-nitroso compounds, direct deamination of DNA bases, and oxidation of DNA after formation of peroxynitrite and/or hydroxyl radicals. One or more of these mechanisms could, theoretically, explain why chronic infection increases the risk of certain cancers.