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Journal of Biomedicine and Biotechnology
Volume 2012 (2012), Article ID 623019, 11 pages
http://dx.doi.org/10.1155/2012/623019
Review Article

Role of Nitrative and Oxidative DNA Damage in Inflammation-Related Carcinogenesis

1Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Tsu, 514-8507, Japan
2Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, 513-8670, Japan
3Faculty of Health Science, Suzuka University of Medical Science, Suzuka, 510-0293, Japan

Received 28 July 2011; Accepted 7 October 2011

Academic Editor: Vassilis Gorgoulis

Copyright © 2012 Mariko Murata et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Chronic inflammation induced by biological, chemical, and physical factors has been found to be associated with the increased risk of cancer in various organs. We revealed that infectious agents including liver fluke, Helicobacter pylori, and human papilloma virus and noninfectious agents such as asbestos fiber induced iNOS-dependent formation of 8-nitroguanine and 8-oxo-7, 8-dihydro-2′-deoxyguanosine (8-oxodG) in cancer tissues and precancerous regions. Our results with the colocalization of phosphorylated ATM and γ-H2AX with 8-oxodG and 8-nitroguanine in inflammation-related cancer tissues suggest that DNA base damage leads to double-stranded breaks. It is interesting from the aspect of genetic instability. We also demonstrated IL-6-modulated iNOS expression via STAT3 and EGFR in Epstein-Barr-virus-associated nasopharyngeal carcinoma and found promoter hypermethylation in several tumor suppressor genes. Such epigenetic alteration may occur by controlling the DNA methylation through IL-6-mediated JAK/STAT3 pathways. Collectively, 8-nitroguanine would be a useful biomarker for predicting the risk of inflammation-related cancers.