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 radic al produced by many types of cells for a number of important physiolog ical functions, is elevated in these infections. Long-term exposure to elevated NO . in cells could have potential genotoxic effects on host s. There are at least three mechanisms by which intracellular elevated NO . could exert genotoxic affects after reacting with O-2. These inc lude formation of carcinogenic N-nitroso compounds, direct deamination of DNA bases, and oxidation of DNA after formation of peroxynitrite a nd/or hydroxyl radicals. One or more of these mechanisms could, theore tically, explain why chronic infection increases the risk of certain c ancers.