Roles of reactive nitrogen species in Helicobacter-related carcinogenesis

Although data indicate an association between Helicobacter infection and gastric carcinogenesis, the precise mechanism for Helicobacter-related carcinogenesis are not yet clarified. An extract of Helicobacter stimulated inflammatory production of nitric oxide (NO) and other reactive nitrogen species. Nitrotyrosine, an adduct of active nitrogen species, increased in gastric epithelia in subjects with the infection. Studies show that reactive nitrogen species cause point mutations at CpG sites; and that such mutations in the p53 gene are frequently found in cancerous and precancerous lesions in the stomach. Thus, reactive nitrogen species including inflammatory NO might play important roles in Helicobacter-induced gastric carcinogenesis.