1 study did not supply age and sex information. 6 studied Chinese population, ,, ,, , 1 studied Japanese population, and 1 studied Korean population. All studies were conducted in East Asia, an area with high incidence of HCC. Table 1 shows the detailed characteristics of each study. In total, 2369 cases and 2442 controls were included. These 8 independent studies were published from 2004 to 2012 with 5 in Chinese language, ,, , and 3 in English. There were 8 studies identified on the hOGG1 Ser326Cys polymorphism and HCC susceptibility ( Figure 1), ,, ,,. The performance and report of this meta-analysis comply with PRISMA Statement (see Methods S3). This meta-analysis has a protocol (see Methods S2). All statistical analyses were performed with STATA software (version 10.0, StataCorp LP, College Station, Texas, USA) and RevMan software (version 5.1, Cochrane Collaboration). Egger’s test and Begg’s graphical methods were used to provide diagnosis of the potential publication bias. Otherwise, the random-effect model (DerSimonian and Laird method) was used. A P value of more than 0.05 for the Q test indicated a lack of heterogeneity among the studies, so the summary OR estimate of each study was calculated by the fixed-effect model (the Mantel-Haenszel method). Heterogeneity assumption was checked by the I 2 statistic and a chi-square based Q test. Sensitivity analyses were carried out using the one-study remove approach to assess the impact of each study on the combined effect. HWE was tested using the chi-squared test and it was considered statistically significant when the P value is less than 0.05. Ser/Ser) and the recessive model (Cys/Cys vs. Ser/Ser), the dominant model (Ser/Cys+Cys/Cys vs. The association was examined under three genetic models: the additive model (Cys/Cys vs. ORs with 95% CIs were calculated to assess the strength of the association between the hOGG1 Ser326Cys polymorphism and HCC risk. We referred to a previous study to perform statistical analysis. We therefore performed a meta-analysis of published studies to investigate whether the Ser326Cys polymorphism has an effect on HCC susceptibility. Such inconsistency could be due partly to insufficient power, the small effect of the Ser326Cys polymorphism on HCC risk and false-positive results. However, the others found no association, ,,. Some found that the Cys allele was associated with increased risk of HCC. In the past years, several studies have investigated the association of the hOGG1 Ser326Cys polymorphism with HCC risk among East Asians, ,, ,,. Although the evidence is inconclusive that this functional polymorphic variation influences the activity of hOGG1, many epidemiologic studies have been conducted to examine its relationship with cancer risk. It is in exon 7 of the hOGG1 gene, which takes the form of a single amino acid substitution, from serine to cysteine at condon 326. Among many polymorphisms identified in the hOGG1 gene, much interest has been focused on the Ser326Cys (C>G) polymorphism (rs1052133). Polymorphisms in this gene may alter glycosylase function and an individual’s ability to repair damaged DNA, possibly resulting in genetic instability that can foster carcinogenesis. The hOGG1 gene, located on chromosome 3p26.2, is composed of eight exons and seven introns. Human 8-hydroxyguanine glycosylase 1 (hOGG1) is a DNA glycosylase enzyme responsible for the excision of 8-oxoguanine, a mutagenic base byproduct which occurs as a result of exposure to reactive oxygen. In the past two decades, more and more GWAS (genome-wide association studies) and other gene-disease association studies have found that some variants in human genes are associated with HCC, indicating that genetic background also plays a role in hepatocellular carcinogenesis. Other well-established risk factors for HCC include chronic infection with hepatitis C virus (HCV), exposure to aflatoxin B1, male gender, drinking, smoking, non-alcoholic fatty liver disease and diabetes, ,. The highest prevalence of HCC is in East Asia due to the high prevalence of chronic infection with hepatitis B virus (HBV). Hepatocellular carcinoma (HCC) is the sixth most prevalent cancer and the third most frequent cause of cancer-related death worldwide.
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