Chronic infection and inflammation contribute to a substantial part of environmental carcinogenesis. Recently, it has been estimated that chronic inflammation accounts for approximately 25% of cancer cases. Various infectious diseases and physical, chemical, and immunological factors participate in inflammation-related carcinogenesis. Under inflammatory conditions, reactive oxygen and nitrogen species, which are generated from inflammatory and epithelial cells, may play an important role in carcinogenesis by causing DNA damage. 8-Nitroguanine is a mutagenic DNA lesion formed during chronic inflammation. In an earlier publication, our group reported the results of an immunohistochemical analysis of animals infected with the liver fluke Opisthorchis viverrini and demonstrated for the first time that 8-nitroguanine was formed at the sites of carcinogenesis. This DNA lesion was found to accumulate in the carcinogenic process in clinical specimens of cancer-prone inflammatory diseases caused by various pathogens, including human papillomavirus and Epstein-Barr virus. Moreover, strong 8-nitroguanine formation in tumor tissues was closely associated with a poor prognosis. On the basis of these findings, 8-nitroguanine could be a potential biomarker to evaluate the risk of inflammation-related carcinogenesis and the prognosis of cancer patients. In this review, the significance of 8-nitroguanine formation in inflammation-related carcinogenesis and tumor progression will be discussed.

BACKGROUND: Many studies have already reported on the relationship between exercise habits and health among schoolchildren. However, few have examined social and/or family factors as determinants of exercise habits. METHODS: This study's participants included 1721 schoolchildren aged between 6 and 13 who were involved in the Super Shokuiku School Project in January 2016. A survey was conducted to assess gender, grade level, physical activity, lifestyle, overall health, enrichment of school life, social background, and parental lifestyles. Both dislike and lack of physical activity were used to measure poor exercise habits; correlates were analyzed using logistic regression. RESULTS: "Lack of close friends" had the strongest links with both dislike (adjusted odds ratio [OR] 5.30; 95% confidence interval [CI], 2.78-10.1) and lack of (adjusted OR 5.40; 95% CI, 2.81-10.4) physical activity. Further, children who engaged in long periods of screen time and lacked parental communication also tended to dislike and lack physical activity. Children with mothers who were unemployed (housewives) and had unhealthy lifestyles, as well as those with poor health, were also more likely to lack physical activity. CONCLUSION Social and family factors (e.g., having close friends) may be determinants of exercise habits among schoolchildren, independent of their own lifestyle factors. Although a longitudinal study is needed to determine causality, substantial attention may thus be required to these factors when promoting physical activity in children.
Adolescent ; Age Factors ; Child ; Cross-Sectional Studies ; Exercise ; psychology ; Family Characteristics ; Female ; Habits ; Humans ; Japan ; Life Style ; Male ; Sex Factors ; Socioeconomic Factors