| [ Summary ] |
Chronic inflammation and infection have long been known to be risk factors for cancer. We focusedon a hypothesis, explaining the role of infection in re]ation to cancer and reactive oxygenradical generation by phagocytic cells, exerting cytotoxicity and promoting mutagenesis. Nitric oxide (NO), a pleiotropic messenger molecule,playing key roles in many physiological and pathological processes, is overproduced under conditions associated with inflammation,infection,and other diseases. When present in high concentrations, NO and reactive nitrogen derivatives have cytotoxic and mutagenic effects. Nitrous anhydride (N203), an intermediate in the reaction of NO with molecular oxygen, damages DNA through DNA alkylation by N-nitroso-amines and DNA deamination. Peroxynitrite(ONOO-), an intermediate in the reaction of NO withO2, causes DNAoxidation and nitration. These reactions may be involved in the carcinogenic process, and NO may play an important role in multistage carcinogenesis. |