Immunohistochemical analysis of 8-nitroguanine, a nitrative DNA lesion, in relation to inflammation-associated carcinogenesis.

Chronic inflammation is induced by various infectious/infected agents and by many physical, chemical and immunological factors. Many malignancies arise from areas of infection and inflammation. Reactive oxygen species and reactive nitrogen species are considered to play the key role in inflammation-associated carcinogenesis by causing oxidative and nitrative DNA damage. 8-Nitroguanine is a mutagenic nitrative DNA lesion formed during inflammation. Development of a detection method for 8-nitroguanine would provide an insight into the mechanism of inflammation-associated carcinogenesis and the assessment of carcinogenic risk in patients with inflammatory diseases. We established the method to produce highly sensitive and specific anti-8-nitroguanine rabbit polyclonal antibody, and detect 8-nitroguanine formation in biopsy specimens and animal tissues by immunohistochemistry. We have found that 8-nitroguanine is formed at the sites of carcinogenesis regardless of etiology, and proposed the possibility that 8-nitroguanine is a potential biomarker to evaluate the risk of inflammation-associated carcinogenesis. In this paper, we describe the procedures of these experiments and the application to clinical specimens and animal tissues.