No association between hOGG1, XRCC1, and XPD polymorphisms and risk of reflux esophagitis, Barrett's esophagus, or esophageal adenocarcinoma: results from the factors influencing the Barrett's adenocarcinoma relationship case-control study

Significant Contribution of DNA Repair Human 8-Oxoguanine DNA N-Glycosylase 1 Genotypes to Renal Cell Carcinoma

Introduction

DNA repair systems play essential roles in genomic stability and carcinogenesis. Therefore, genotypes at DNA repair loci may contribute to the determination of personal susceptibility to cancers. The contribution of human 8-oxoguanine DNA N-glycosylase 1 (hOGG1) genotypes to renal cell carcinoma (RCC) is largely unknown. This study aimed to evaluate the contributions of hOGG1 rs1052133 genotypes to the RCC risk.

Methods

We evaluated the contribution of hOGG1 rs1052133 (G/C) genotypes among 118 cases and 590 controls and analyzed the interactions of hOGG1 genotypes with smoking, alcohol drinking, hypertension, and diabetes status.

Results

The hOGG1 rs1052133 CC genotype was significantly associated with a decreased RCC risk compared with that of the GG genotype (odds ratio [OR] = 0.25, 95% confidence interval [CI] = 0.09–0.72, p = 0.0049). The frequency of the rs1052133 C allele was significantly low in the RCC group (22.5% vs 31.2%; OR = 0.64; 95% CI = 0.46–0.89, p = 0.0074). Stratifying the analysis according to smoking, alcohol drinking, and diabetes status revealed no difference in the rs1052133 genotype distribution among these subgroups. A significant differential distribution of rs1052133 genotypes was observed among subjects with hypertension.

Conclusion

The CC genotype of rs1052133 may play a role in determining RCC susceptibility among Taiwanese people and may serve as a biomarker of RCC, particularly in patients with hypertension.

HOGG1 rs1052133 Genotypes and Risk of Childhood Acute Lymphoblastic Leukemia in a Taiwanese Population

BACKGROUND/AIM

Cells suffer from oxidative DNA damage which leads to the accumulation of 8-oxoguanine (8-oxoG) adducts in our genome that can become carcinogenic. The human 8-oxoG DNA glycosylase 1 (hOGG1) plays a central role in repairing these 8-oxoGs via the base excision repair pathway. Mounting evidence has suggested that hOGG1 polymorphisms may affect the activity of hOGG1 and serve as genomic markers for the prediction of personal susceptibility to several cancers. To determine whether the commonly examined hOGG1 rs1052133 (Ser326Cys) polymorphism is associated with the risk of childhood acute lymphoblastic leukemia (ALL) among Taiwanese children, we genotyped the hOGG1 rs1052133 (Ser326Cys) in 266 cases and 266 controls.

RESULTS

The distributions of the GG, CG and CC genotypes at the hOGG1 rs1052133 were 49.2, 39.1 and 11.7% in the control group and 48.1, 36.1 and 15.8% in the case group (p=0.3656). The combined genotypes CG+CC were not associated with increased risk of childhood ALL (odds ratio [OR]=1.05, 95% confidence interval [CI]=0.74-1.47, p=0.7947).

CONCLUSION

The hOGG1 rs1052133 polymorphism is not associated with susceptibility to childhood ALL in the Taiwanese population.

The hOGG1 Ser326Cys polymorphism and esophageal cancer risk: a meta-analysis of 1,875 cancer cases and 3,041 controls

Background

Recently, there have been several studies that have looked at the association between hOGG1 Ser326Cys polymorphism and esophageal cancer (EC) risk. However, the results of previous reports remain controversial and ambiguous. Thus, we performed a meta-analysis to explore more precisely the association between hOGG1 Ser326Cys polymorphism and the risk of EC.

Methods

A meta-analysis was performed to examine the association between hOGG1 Ser326Cys polymorphism and EC risk. Odds ratio (OR) and its 95% confidence interval (CI) were used for statistical analysis.

Results

Our publication search identified a total of 9 studies with 1,875 cases and 3,041 controls. There was no significant associations in all genetic models between hOGG1 Ser326Cys polymorphism and EC observed (OR =1.024, 95% CI: 0.932-1.125 for Cys vs. Ser, P=0.624; OR =1.126, 95% CI: 0.901-1.408 for Cys/Cys vs. Ser/Ser, P=0.296; OR = 0.961, 95% CI: 0.844-1.093 for Ser/Cys vs. Ser/Ser, P =0.540; OR =0.989, 95% CI: 0.874-1.118 for Cys/Cys + Ser/Cys vs. Ser/Ser, P=0.855; OR =1.165, 95% CI: 0.945-1.436 for Cys/Cys vs. Ser/Cys + Ser/Ser, P=0.153). Also, in the stratified analyses by ethnicity and cancer type, no significant association was observed.

Conclusions

This meta-analysis on hOGG1 Ser326Cys polymorphism and the risk of EC suggests there is no statistically significant association between the two. Additional primary studies may be necessary to provide evidence of any significant association between this specific polymorphism and EC.

Human 8-oxoguanine DNA glycosylase gene polymorphism (Ser326Cys) and cancer risk: updated meta-analysis

Genetic polymorphism of human 8-oxoguanine glycosylase 1 (hOGG1) has been reported to have a relationship with the risk of the development of various cancers. Many studies have described the influence of Ser326Cys polymorphism of the hOGG1 gene on cancer susceptibility. However, the results have remained inconclusive and controversial. Therefore, we performed a meta-analysis to more precisely determine the relationship between the hOGG1 polymorphism and the development of cancer.Electronic databases including PubMed, Embase, Google Scholar, and the Korean Studies Information Service System (KISS) were searched. The odds ratio (OR), 95% confidence interval (CI), and p value were calculated to assess the strength of the association with the risk of cancer using Comprehensive Meta-analysis software (Corporation, NJ, USA). The 127 studies including 38,757 cancer patients and 50,177 control subjects were analyzed for the meta-analysis.Our meta-analysis revealed that G allele of Ser326Cys polymorphism of the hOGG1 gene statistically increased the susceptibility of cancer (all population, OR = 1.092, 95% CI = 1.051-1.134, p < 0.001; in Asian, OR = 1.095, 95% CI = 1.048-1.145, p < 0.001; in Caucasian, OR = 1.097, 95% CI = 1.033-1.179, p = 0.002). Also, other genotype models showed significant association with cancer (p < 0.05, respectively).The present meta-analysis concluded that the G allele was associated with an increased risk of cancer. It suggested that the hOGG1 polymorphism may be a candidate marker of cancer.

Association between circulating levels of sex steroid hormones and esophageal adenocarcinoma in the FINBAR Study

Background

Esophageal adenocarcinoma (EA) is characterized by a strong male predominance. Sex steroid hormones have been hypothesized to underlie this sex disparity, but no population-based study to date has examined this potential association.

Methods

Using mass spectrometry and ELISA, we quantitated sex steroid hormones and sex hormone binding globulin, respectively, in plasma from males– 172 EA cases and 185 controls–within the Factors Influencing the Barrett/Adenocarcinoma Relationship (FINBAR) Study, a case-control investigation conducted in Northern Ireland and Ireland. Multivariable adjusted logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between circulating hormones and EA.

Results

Higher androgen:estrogen ratio metrics were associated with increased odds of EA (e.g., testosterone:estradiol ratio OR_{Q4 v. Q1} = 2.58, 95%CI = 1.23–5.43; P_trend = 0.009). All estrogens and androgens were associated with significant decreased odds of EA. When restricted to individuals with minimal to no decrease in body mass index, the size of association for the androgen:estrogen ratio was not greatly altered.

Conclusions

This first study of sex steroid hormones and EA provides tentative evidence that androgen:estrogen balance may be a factor related to EA. Replication of these findings in prospective studies is needed to enhance confidence in the causality of this effect.

Association between the OGG1 Ser326Cys Polymorphism and Cancer Risk: Evidence from 152 Case-Control Studies

Although it has been suggested that the 8-oxoguanine DNA glycosylase (OGG1) gene Ser326Cys polymorphism may be a risk factor for cancer, the conclusions from previous studies are inconsistent. Thus, we conducted an updated meta-analysis to estimate the effect of OGG1 variant genotypes on cancer susceptibility. We searched the PubMed for all eligible studies published in English for the period ending September 2014. We found the association between OGG1 Ser326Cys polymorphism and cancer susceptibility based on 152 case-control studies in different genetic model comparisons (dominant model: OR = 1.053, P = 0.018; recessive model: OR = 1.108, P < 0.001; homozygote: OR = 1.135, P < 0.001; additive model: OR = 1.059, P < 0.001). However, the results from the subgroup analyses based on types of cancer, health population as controls or studies with relatively large sample size did not support the conclusion. Although the overall results of this meta-analysis showed a positive association between OGG1 variant genotypes and cancer susceptibility, the subgroup analyses by cancer type, sample size, and source of controls presented inconsistent results. Therefore, the current evidence from the meta-analysis did not support the hypothesis of OGG1 Ser326Cys polymorphism as a risk factor of cancer.

Genetic Biomarkers of Barrett's Esophagus Susceptibility and Progression to Dysplasia and Cancer: A Systematic Review and Meta-Analysis

Barrett's esophagus (BE) is a common and important precursor lesion of esophageal adenocarcinoma (EAC). A third of patients with BE are asymptomatic, and our ability to predict the risk of progression of metaplasia to dysplasia and EAC (and therefore guide management) is limited. There is an urgent need for clinically useful biomarkers of susceptibility to both BE and risk of subsequent progression. This study aims to systematically identify, review, and meta-analyze genetic biomarkers reported to predict both. A systematic review of the PubMed and EMBASE databases was performed in May 2014. Study and evidence quality were appraised using the revised American Society of Clinical Oncology guidelines, and modified Recommendations for Tumor Marker Scores. Meta-analysis was performed for all markers assessed by more than one study. A total of 251 full-text articles were reviewed; 52 were included. A total of 33 germline markers of susceptibility were identified (level of evidence II-III); 17 were included. Five somatic markers of progression were identified; meta-analysis demonstrated significant associations for chromosomal instability (level of evidence II). One somatic marker of progression/relapse following photodynamic therapy was identified. However, a number of failings of methodology and reporting were identified. This is the first systematic review and meta-analysis to evaluate genetic biomarkers of BE susceptibility and risk of progression. While a number of limitations of study quality temper the utility of those markers identified, some-in particular, those identified by genome-wide association studies, and chromosomal instability for progression-appear plausible, although robust validation is required.

Genetic susceptibility to Barrett's oesophagus: Lessons from early studies

Barrett’s oesophagus (BO) is a common condition, predisposing strongly to the development of oesophageal adenocarcinoma (OAC). Consequently, there has been considerable effort to determine the processes involved in the development of BO metaplasia, and ultimately develop markers of patients at risk. Whilst a number of robust acquired risk factors have been identified, a genetic component to these and the apparent increased susceptibility of certain individuals has long been suspected. This has been evidenced in part by linkage studies, but subsequently two recent genome-wide association studies (GWAS) have suggested mechanisms underlying the heritability of BO, as well as providing the first direct evidence at modern levels of statistical significance. This review discusses BO heritability, in addition to that of individual variants and genes reported to be associated with BO to date. Through this, we identify a number of plausible associations, although often tempered by issues of methodology, and discuss the priorities and need for future research.

XPD Lys751Gln polymorphisms and the risk of esophageal cancer: an updated meta-analysis

OBJECTIVE

Published data regarding the association between xeroderma pigmentosum group D XPD Lys751Gln polymorphisms and esophageal cancer (EC) cancer remain controversial. The present meta-analysis aimed to obtain a more precise estimation of the relationship between XPD Lys751Gln polymorphisms and the risk of EC.

METHODS

All eligible case-control studies of Lys751Gln polymorphisms and susceptibility to EC were selected from PubMed, Web of Science and CNKI up to October 2013. The data were extracted, and pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.

RESULTS

A total of 21 case-control studies from 19 reports were assessed in this meta-analysis, including 6,581 cases and 8,251 controls. There was a significant association between the XPD Lys751Gln polymorphism and the risk of esophageal cancer in the overall population (Dominant model: OR=1.30, 95%CI: 1.07-1.57, p<0.05; Lys/Gln vs. Gln/Gln: OR=1.20, 95%CI: 1.05-137, p<0.05; Gln/Gln vs. Lys/Lys: OR=1.76, 95%CI: 1.08-2.85, p=0.02; Recessive model: OR=1.48, 95%CI: 1.06-2.07, p=0.02). Similar results were found when stratified according to the cancer type, ethnicity and control source. However, no associations were found among smokers or drinkers.

CONCLUSION

The results of this meta-analysis suggest that XPD Lys751Gln polymorphisms contribute to susceptibility to EC.

Xeroderma pigmentosum group D polymorphisms and esophageal cancer susceptibility: A meta-analysis based on case-control studies

AIM: To clarify the effects of the xeroderma pigmentosum group D (XPD) Asp312Asn and Lys751Gln gene polymorphisms on the risk of esophageal cancer (EC).

METHODS: A computerised literature search was conducted to identify the relevant studies from the PUBMED and EMBASE databases, reviews, and reference lists of relevant articles. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the associations between the XPD Asp312Asn and/or Lys751Gln polymorphisms and EC susceptibility. Statistical analyses were performed using the software Stata 12.0. A fixed or random effects model was selected based on a heterogeneity test. Publication bias was estimated using funnel plots and Egger’s linear regression method. Subgroup analyses were performed based on histological type and ethnicity.

RESULTS: Thirteen case-control studies with a total of 10 comparisons for the Asp312Asn polymorphism, including 2373 cases and 3175 controls, and 15 comparisons for the Lys751Gln polymorphism, including 3226 cases and 5237 controls, were recruited for the meta-analysis. In terms of the XPD Asp312Asn polymorphism, significantly increased EC risks were identified in the Asp/Asn vs Asp/Asp comparison (OR = 1.17, 95%CI: 1.02-1.33, P = 0.03) and in the dominant-model comparison (Asn/Asn+Asp/Asn vs Asp/Asp: OR = 1.18, 95%CI: 1.04-1.34, P = 0.01). However, no significant associations were found in the Asn/Asn vs Asp/Asp comparison (OR = 1.30, 95%CI: 1.00-1.70, P = 0.05) or in the recessive-model comparison (Asn/Asn vs Asp/Asn + Asp/Asp: OR = 1.17, 95%CI: 0.91-1.50, P = 0.22). In terms of the XPD Lys751Gln polymorphism, a significant association with EC susceptibility was found under the recessive model (Gln/Gln vs Lys/Gln+Lys/Lys: OR = 1.21, 95%CI: 1.02-1.43, P = 0.03). However, no associations were identified in the other comparisons (co-dominant model: Lys/Gln vs Lys/Lys: OR = 1.11, 95%CI: 0.94-1.31, P = 0.20; Gln/Gln vs Lys/Lys: OR = 1.31, 95%CI: 0.98-1.75, P = 0.07; dominant model: OR = 1.14, 95%CI: 0.96-1.35, P = 0.14).

CONCLUSION: The results of this meta-analysis suggest that the XPD Asp312Asn and Lys751Gln gene polymorphisms are associated with a significantly increased risk for EC.

The hOGG1 Ser326Cys polymorphism contributes to digestive system cancer susceptibility: evidence from 48 case-control studies

The Ser326Cys polymorphism in the human 8-oxogunaine DNA glycosylase (hOGG1) gene had been implicated in cancer susceptibility. Studies investigating the associations between the Ser326Cys polymorphism and digestion cancer susceptibility showed conflicting results. Therefore, a meta-analysis was performed to derive a more precise estimation of the relationship. We conducted a meta-analysis of 48 studies that included 12,073 cancer cases and 19,557 case-free controls. We assessed the strength of the association using odds ratios (ORs) with 95% confidence intervals (CIs). In our analysis, the hOGG1 Ser326Cys polymorphism was significantly associated with the risk of digestive system cancers (Cys/Cys vs. Ser/Ser: OR = 1.17, 95% CI = 1.00-1.35, P < 0.001; Cys/Cys vs. Cys/Ser + Ser/Ser: OR = 1.14, 95% CI = 1.00-1.29, P < 0.001). In subgroup analyses by cancer types, we found that the hOGG1 Ser326Cys polymorphism may increase hepatocellular cancer and colorectal cancer risks, but decrease the risk of oral cancer. These findings supported that hOGG1 Ser326Cys polymorphism may contribute to the susceptibility of digestive cancers.

The effect of XPD polymorphisms on digestive tract cancers risk: a meta-analysis

Background

The Xeroderma pigmento-sum group D gene (XPD) plays a key role in nucleotide excision repair. Single nucleotide polymorphisms (SNP) located in its functional region may alter DNA repair capacity phenotype and cancer risk. Many studies have demonstrated that XPD polymorphisms are significantly associated with digestive tract cancers risk, but the results are inconsistent. We conducted a comprehensive meta-analysis to assess the association between XPD Lys751Gln polymorphism and digestive tract cancers risk. The digestive tract cancers that our study referred to, includes oral cancer, esophageal cancer, gastric cancer and colorectal cancer.

Methods

We searched PubMed and EmBase up to December 31, 2012 to identify eligible studies. A total of 37 case-control studies including 9027 cases and 16072 controls were involved in this meta-analysis. Statistical analyses were performed with Stata software (version 11.0, USA). Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association.

Results

The results showed that XPD Lys751Gln polymorphism was associated with the increased risk of digestive tract cancers (homozygote comparison (GlnGln vs. LysLys): OR = 1.12, 95% CI = 1.01–1.24, P = 0.029, P_{heterogeneity} = 0.133). We found no statistical evidence for a significantly increased digestive tract cancers risk in the other genetic models. In the subgroup analysis, we also found the homozygote comparison increased the susceptibility of Asian population (OR = 1.28, 95% CI = 1.01–1.63, P = 0.045, P_{heterogeneity} = 0.287). Stratified by cancer type and source of control, no significantly increased cancer risk was found in these subgroups. Additionally, risk estimates from hospital-based studies and esophageal studies were heterogeneous.

Conclusions

Our meta-analysis suggested that the XPD 751Gln/Gln genotype was a low-penetrate risk factor for developing digestive tract cancers, especially in Asian populations.

Deoxyribonucleic acid repair gene X-ray repair cross-complementing group 1 polymorphisms and non-carcinogenic disease risk in different populations: A meta-analysis

PURPOSE

This study aims to assess a meta-analysis of the association of X-ray repair cross-complementing group 1 (XRCC1) polymorphisms with the risk of various non-carcinogenic diseases in different population.

MATERIALS AND METHODS

This meta-analysis was performed by critically reviewing reveals 38 studies involving 10043 cases and 11037 controls. Among all the eligible studies, 14 focused on Arg194Trp polymorphism, 33 described the Arg399Gln and three articles investigated on Arg280His. Populations were divided into three different ethnic subgroups include Caucasians, Asians and other (Turkish and Iranian).

RESULTS

Pooled results showed no correlation between Arg194Trp and non-carcinogenic disease. There was only weak relation in the recessive (odds ratio [OR] =1.11, 95% confidence interval [CI]: 0.86-1.44) model in Asian population and dominant (OR = 1.04, 95% CI: 0.66-1.63) model of other populations. In Arg399Gln polymorphism, there was no relation with diseases of interest generally. In the pooled analysis, there were weak relation in the dominant (OR = 1.08, 95% CI: 0.86-1.35) model of Asian population and quite well-correlation with recessive (OR = 1.49, 95% CI: 1.19-1.88), dominant (OR = 1.23, 95% CI: 0.94-1.62), and additive (OR = 1.23, 95% CI: 0.94-1.62) models of other subgroup. For Arg280His, there was a weak relation only in the dominant model (OR = 1.06, 95% CI: 0.74-1.51).

CONCLUSION

The present meta-analysis correspondingly shows that Arg399Gln variant to be associated with increased non-carcinogenic diseases risk through dominant and recessive modes among Iranian and Turkish population. It also suggests a trend of dominant and recessive effect of Arg280His variant in all population and its possible protective effect on non-carcinogenic diseases.

Association between the c.910A>G genetic variant of the XRCC1 gene and susceptibility to esophageal cancer in the Chinese Han population

Esophageal cancer (EC) is a common malignancy worldwide. The X-ray repair cross-complementing 1 gene (XRCC1) is one of the most important candidate genes for influencing susceptibility to EC. This study aimed to investigate the effect of XRCC1 genetic variants on susceptibility to EC. A total of 383 EC patients (males: 239, females: 144, mean age: 56.62) and 387 cancer-free controls (males: 251, females: 136, mean age: 58.23) were enrolled in this study. The c.910A>G genetic variant of the XRCC1 gene was determined by polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing methods. The allele and genotype frequencies indicated statistical differences between EC patients and cancer-free controls. The c.910A>G genetic variant was statistically associated with increased susceptibility to EC [GG vs AA: odds ratio (OR)=1.79, 95% confidence interval (CI)=1.12-2.86, P=0.014; GG vs AG/AA: OR=1.76, 95%CI=1.13-2.75, P=0.013; G vs A: OR=1.25, 95%CI=1.01-1.55, P=0.041]. The allele G and genotype GG could contribute to the increased susceptibility to EC. Our findings suggest that the c.910A>G genetic variant is associated with susceptibility to EC in the Chinese Han population, and might be used as a molecular marker for detecting susceptibility to EC.

The OGG1 Ser326Cys polymorphism and the risk of esophageal cancer: a meta-analysis

BACKGROUND

The oxoguanine DNA glycosylase (OGG1) Ser326Cys polymorphism has been implicated in susceptibility to esophageal cancer. Several studies investigated the association of this polymorphism with esophageal cancer in different populations. However, the results were contradictory. A meta-analysis was conducted to assess the association between the OGG1 Ser326Cys polymorphism and esophageal cancer susceptibility.

METHODS

Databases, including PubMed, EMBASE, China National Knowledge Infrastructure (CNKI), and Weipu Database were searched to find relevant studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. A random-effects model was used.

RESULTS

Twelve studies involving 2363 cases and 3621 controls were included. Overall, a significant association between the OGG1 Ser326Cys polymorphism and esophageal cancer was observed for Cys/Cys versus Cys/Ser+Ser/Ser (OR=1.40; 95% CI 1.12-1.74; p=0.003; Pheterogeneity=0.18). In the subgroup analysis by ethnicity, a significant association was found among Asians (OR=1.51; 95% CI 1.15-1.96; p=0.002; Pheterogeneity=0.22), but not among Caucasians (OR=1.21; 95% CI 0.81-1.81; p=0.35; Pheterogeneity=0.21). In the subgroup analysis by pathologic type, we found that the Cys/Cys genotype was associated with increased esophageal squamous cell carcinoma risk (OR=1.86; 95% CI 1.36-2.53; p<0.0001; Pheterogeneity=0.73).

CONCLUSIONS

This meta-analysis suggested that the OGG1 Ser326Cys polymorphism was a risk factor of esophageal cancer.

XRCC1 Arg399Gln, Arg194Trp, and Arg280His polymorphisms in esophageal cancer risk: a meta-analysis

BACKGROUND

The X-ray repair cross-complementation group 1 (XRCC1) protein plays an important role in base excision repair.

AIM

To elucidate the role of XRCC1 Arg399Gln, Arg194Trp and Arg280His genotypes in esophageal cancer risk, all available studies were considered in the present meta-analysis.

METHODS

Eligible studies were identified by searching several electronic databases for relevant reports published before June 2012.

RESULTS

According to the inclusion criteria and exclusion criteria, a total of 21 eligible studies were included in the pooled analyses. Among the 21 studies, 18 focused on Arg399Gln polymorphism, 11 described the Arg194Trp, and 4 articles investigated on Arg280His. Our analysis suggested that there was no evidence of significant association between XRCC1 Arg399Gln polymorphism and esophageal cancer risk in any genetic model. In the stratified analysis by ethnicity for Arg399Gln polymorphism and esophageal cancer, the results showed that Arg399Gln polymorphism was not associated with esophageal cancer risk. Only 4 studies analyzed the relationship between XRCC1 Arg280His polymorphism and the risk of esophageal cancer. The Arg/His and His/His genotypes were not significantly associated with increased risk of EC. A similar negative association was maintained in dominant and recessive models. However, for XRCC1 Arg194Trp polymorphism, our study showed individuals carrying the variant genotype Trp/Trp had a significant increased risk of esophageal cancer (OR = 1.295, 95 % CI 1.053-1.591, P = 0.014). In addition, increased associations were found in recessive model (OR = 1.332, 95 % CI 1.093-1.624, P = 0.005).

CONCLUSIONS

Our meta-analysis suggested that Arg194Trp Trp allele might act as a risk allele in its association with esophageal cancer.

A meta-analysis of the association between the hOGG1 Ser326Cys polymorphism and the risk of esophageal squamous cell carcinoma

BACKGROUND

Genetic polymorphism of human 8-oxoguanine glycosylase 1 (hOGG1) Ser326Cys (rs1052133) has been implicated in the risk of Esophageal Squamous Cell Carcinoma (ESCC). However, the published findings are inconsistent. We therefore performed a meta-analysis to derive a more precise estimation of the association between the hOGG1 Ser326Cys polymorphism and ESCC risk.

METHODOLOGY/PRINCIPAL FINDINGS

A comprehensive search was conducted to identify eligible studies of hOGG1 Ser326Cys polymorphism and the risk of the ESCC. Three English and two Chinese databases were used, and ten published case-control studies, including 1987 cases and 2926 controls were identified. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the association in the dominant and recessive model. Pearson correlation coefficient (PCC) and standard error (SE) were used to assess the number of Cys allele and ESCC risk in the additive model. Overall, significant associations between the hOGG1 Ser326Cys polymorphism and ESCC risk were found in the recessive model: OR = 1.37 (95% CI: 1.06-1.76, p = 0.02). We also observed significant associations in the Caucasian, Chinese language, population based control and tissue subgroups. In the additive model, positive correlation was found between the number of Cys allele and the risk of ESCC in overall studies (PCC = 0.109, SE = 0.046, p = 0.02), Caucasian subgroup and population subgroup. Funnel plot and Egger's test indicate there was no publication bias in this meta-analysis.

CONCLUSION

Under the published data, the hOGG1 Ser326Cys polymorphism is associated with ESCC risk in the recessive and additive model. Compared with the Ser/Ser and Ser/Cys genotype, Cys/Cys genotype might contribute to increased risk of ESCC. And the risk of ESCC is positively correlated with the number of Cys allele. A better case-control matched study should be designed in order to provide a more precise estimation.

Genetics of Barrett's: the bigger, the better

Barrett's esophagus (BE) is a common lesion that predisposes to a highly fatal esophageal adenocarcinoma (EA). There is evidence that BE or parts of its phenotype are genetically predisposed. Several single-nucleotide polymorphisms (SNPs) have been validated as predisposing to BE but the inherent flaws in the trial sizes, presence of controls and statistical power need circumspect analysis. The current paper links the interleukin 18 cytokine with BE and perhaps EA. Setting aside the issues above there are other issues such as the functional relevance of these SNPs for the association BE. There have been several case control series published indicating other genes. Furthermore, there are some sibling pairs study results with another set of genes identified. Invariably as useful as these studies are the size, scale to answer complex questions (complexity) and potential clinical significance are proportional in genomic studies. The new era of large-scale genome-wide studies in Barrett's and EA is needed. Shortly the first will be published showing two SNPs of significance in 7,838 Barrett's patients.

Genes of the interleukin-18 pathway are associated with susceptibility to Barrett's esophagus and esophageal adenocarcinoma

OBJECTIVES

To investigate the association of genetic polymorphisms of the interleukin-18 (IL-18) pathway to Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC). Most cases of EAC arise in a background of reflux-induced BE. Genetic influences in this pathway are poorly understood. IL-18 is a multifunctional cytokine implicated in anti-tumor immunity. A number of polymorphisms of the IL-18 and IL-18 receptor-accessory protein (IL-18RAP) genes have been reported to alter gene expression and have recently been linked to inflammatory processes and various tumors, but have not heretofore been studied in BE and EAC.

METHODS

Two IL-18 promoter polymorphisms -137 G/C and -607 C/A, (rs187238 and rs1946518) and one IL-18RAP polymorphism (rs917997, C/T) were analyzed. Each single-nucleotide polymorphism (SNP) was genotyped in the following groups: EAC, BE, reflux esophagitis (RE), and controls and analyzed for association with disease status.

RESULTS

The IL-18RAP rs917997C allele is strongly associated with a protective effect in BE (P = 0.0002) and EAC (P = 6 × 10(-7)), which approaches genome-wide levels of significance for allele association without incurring significant multiple testing. The CC genotype at IL-18RAP locus rs917997 was associated with a protective effect against esophageal disease (P = 6 × 10(-4), odds ratio (OR) = 0.59, and 95% confidence interval (CI) 0.43-0.80 for BE; and P = 2 × 10(-6), OR = 0.46, and 95% CI 0.34-0.64 for EAC). The genotype frequencies of IL-18-607 C/A were weakly associated with BE (P = 0.02), and this trend was also seen between controls and EAC (P = 0.07). The CC genotype was associated with an increased risk of BE (OR = 1.45, 95% CI 1.07-1.98) and approached significance for EAC (OR = 1.34, 95% CI 0.98-1.82). Allele and genotype frequencies at these loci were not significantly different between the RE group and controls. Although no significant association was observed between the disease groups at the -137 G/C locus, the -137G/-607C haplotype was associated with increased risk of BE (P = 0.006) with haplotype frequencies of 55% in controls and 65% in BE.

CONCLUSIONS

These data show a strong association of the IL-18RAP SNP rs917997 locus with BE and EAC and suggestive association of the Barrett's population with the IL-18-607 C/A promoter polymorphism. As both of these SNPs have been demonstrated as expression quantitative trait loci affecting expression of the respective genes, this strongly implicates IL-18 signaling in susceptibility to BE and EAC.

The 8-hydroxydeoxyguanosine concentrations according to hormone therapy and S326C polymorphism of OGG1 gene in postmenopausal women

BACKGROUND

The 8-hydroxydeoxyguanosine (8-OHdG) is widely used for determination of DNA damage since it is excised from oxidative damaged DNA with endonuclease repair enzymes coded by 8-oxoguanine DNA N-glycosylase gene (OGG1). The present study aimed at investigating whether hormone therapy (HT) may influence on the blood/urinary 8-OHdG levels and whether the level of 8-OHdG is different according to OGG1 S326C polymorphism in postmenopausal women receiving HT.

METHODS

In 102 postmenopausal women receiving HT, the 8-OHdG levels were measured in the blood and urine using high performance liquid chromatography (HPLC) before HT and 3 months after HT. The genotyping of the S326C polymorphism of the OGG1 was performed by polymerase chain reaction (PCR) and restriction enzyme fragment length polymorphism (RFLP) analysis.

RESULTS

After HT, mean blood 8-OHdG level significantly decreased compared to those before HT (P=0.003), while urinary 8-OHdG level did not show any difference according to HT. Pre-HT level of 8-OHdG was not different according to OGG1 genotypes and similar finding was demonstrated in post-HT 8-OHdG concentration.

CONCLUSIONS

These findings imply that hormone therapy can reduce blood 8-OHdG concentration, one of the markers of oxidative damage. Further study is needed to confirm this association in larger population.

The hOGG1 Ser326Cys polymorphism contributes to cancer susceptibility: evidence from 83 case-control studies

The Ser326Cys polymorphism in the human 8-oxogunaine DNA glycosylase (hOGG1) gene had been implicated in cancer susceptibility. Studies investigating the associations between the Ser326Cys polymorphism and cancer susceptibility showed conflicting results. To derive a more precise estimation of the relationship, a meta-analysis was performed. This meta-analysis was performed from 83 case-control studies, including 27,918 cases and 33,399 controls. The fixed and random effect models were used to estimate the odds ratios (ORs) and their 95% confidence interval (CI) for various contrasts of this polymorphism. The combined results based on all studies showed that the hOGG1 Ser326Cys polymorphism was associated with an increased cancer susceptibility in different genetic models. In the stratified analyses, the association was significantly in head and neck cancer (homozygote comparison: OR = 2.19, 95% CI: 1.20-4.01, P(heterogeneity) = 0.002; heterozygote comparison: OR = 1.48, 95% CI: 1.11-1.99, P(heterogeneity) = 0.004; dominant model comparison: OR = 1.58, 95% CI: 1.14-2.19, P(heterogeneity) < 0.001; recessive model comparison: OR = 1.73, 95% CI: 1.02-2.94, P(heterogeneity) = 0.002; and additive model comparison: OR = 1.43, 95% CI: 1.09-1.88, P(heterogeneity) < 0.001) which remained for studies of the Asian populations and hospital-based of control sources. But it was not observed in other cancer types of the European population and population based of control sources. This meta-analysis suggested that the hOGG1 Ser326Cys polymorphism might contribute to an increased risk on cancer susceptibility. More studies based on larger sample size should be performed to confirm the findings.

The effect of hOGG1 Ser326Cys polymorphism on cancer risk: evidence from a meta-analysis

Background

Human oxoguanine glycosylase 1 (hOGG1) in base excision repair (BER) pathway plays a vital role in DNA repair. Numerous epidemiological studies have evaluated the association between hOGG1 Ser326Cys polymorphism and the risk of cancer. However, the results of these studies on the association remain conflicting. To derive a more precise estimation of the association, we conducted a meta-analysis.

Methodology/Principal Findings

A comprehensive search was conducted to identify the eligible studies of hOGG1 Ser326Cys polymorphism and cancer risk. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. We found that the hOGG1 Ser326Cys polymorphism was significantly associated with overall cancer risk (Cys/Cys vs. Ser/Ser: OR = 1.19, 95%CI = 1.09–1.30, P<0.001; Cys/Cys vs. Cys/Ser+Ser/Ser: OR = 1.16, 95%CI = 1.08–1.26, P<0.001). Moreover, in subgroup analyses by cancer types, the stronger significant association between hOGG1 Ser326Cys polymorphism and lung cancer risk was found (Cys/Cys vs. Ser/Ser: OR = 1.29, 95%CI = 1.16–1.44, P<0.001; Cys/Cys vs. Cys/Ser+Ser/Ser: OR = 1.22, 95%CI = 1.12–1.33, P<0.001). The significant effects of hOGG1 Ser326Cys polymorphism on colorectal, breast, bladder, prostate, esophageal, and gastric cancer were not detected. In addition, in subgroup analyses by ethnicities, we found that the hOGG1 Ser326Cys polymorphism was associated with overall cancer risk in Asians (Cys/Cys vs. Ser/Ser: OR = 1.21, 95%CI = 1.10–1.33, P<0.001).

Conclusions

This meta-analysis showed that hOGG1 326Cys allele might be a low-penetrant risk factor for lung cancer.

DNA repair gene 8-oxoguanine DNA glycosylase Ser326Cys polymorphism and colorectal cancer risk in a Kashmiri population

8-Oxoguanine DNA glycosylase (OGG1) is one of the important base excision repair enzymes that repair 8-oxoguanine lesion incorporated within the DNA of an individual by reactive oxygen species. The aim of this study was to detect the role of OGG1 Ser326Cys polymorphism in susceptibility to colorectal cancer (CRC) in a Kashmiri population. We investigated the genotype distribution of the OGG1 gene in 114 CRC cases in comparison with 200 healthy subjects. There was no significant association between OGG1 Ser326Cys polymorphism and CRC, but the homozygous Cys/Cys variant genotype was associated with an increased risk of colon cancer (p<0.05). This study suggests that the OGG1 polymorphism is not associated with the risk of development of CRC in the Kashmiri population in general but modulates the risk of cancer development in colon via interaction with many dietary factors.

XPD Lys751Gln polymorphism and esophageal cancer susceptibility: a meta-analysis of case-control studies

The published data on the association between xeroderma pigmentosum group D (XPD) Lys751Gln polymorphism and esophageal cancer (EC) remained controversial. The present meta-analysis of literatures was performed to derive a more precise estimation of the relationship. A comprehensive literature search was conducted to identify all case-control studies of Lys751Gln polymorphism and risk for two main types of EC: esophageal adenocarcinoma (EADC) and esophageal squamous cell carcinoma (ESCC). A total of 12 studies were identified to the meta-analysis, including 2,575 cases (1,294 ESCC and 1,281 EADC) and 4,951 controls (1,891 ESCC and 3,060 EADC). Random-effects or fix-effects model was used according to between-study heterogeneity. The odds ratio (OR) for the variant homozygous genotype Gln/Gln of the Lys751Gln polymorphism, compared with the wild type homozygote Lys/Lys, was 1.26, with 95% confidence interval (95% CI) 1.02-1.56, for EADC risk without between-study heterogeneity. When stratified by ethnicity, statistically significantly elevated risk was found among Chinese (Gln/Gln vs. Lys/Lys: OR 2.45, 95% CI = 1.10-5.44). However, no significant associations were found between XPD Lys751Gln polymorphism and EC risk when all studies pooled into the meta-analysis (Lys/Gln vs. Lys/Lys: OR 1.07, 95% CI = 0.88-1.28; Gln/Gln vs.us Lys/Lys: OR 1.25, 95% CI = 0.92-1.71; dominant model: OR 1.09, 95% CI = 0.90-1.33). In conclusion, this meta-analysis suggests that the Lys751Gln genetic polymorphism may be a potential biomarker of EC susceptibility in Chinese populations. And a study with the larger sample size is needed to further evaluate gene-environment interaction on XPD Lys751Gln polymorphism and EC risk.

Genetic variation in DNA-repair pathways and response to radiochemotherapy in esophageal adenocarcinoma: a retrospective cohort study of the Eastern Cooperative Oncology Group

Background

Recent data in esophageal cancer suggests the variant allele of a single-nucleotide polymorphism (SNP) in XRCC1 may be associated with resistance to radiochemotherapy. However, this SNP has not been assessed in a histologically homogeneous clinical trial cohort that has been treated with a uniform approach. In addition, whether germline DNA may serve as a surrogate for tumor genotype at this locus is unknown in this disease. Our objective was to assess this SNP in relation to the pathologic complete response (pCR) rate in subjects with esophageal adenocarcinoma who received cisplatin-based preoperative radiochemotherapy in a multicenter clinical trial (Eastern Cooperative Oncology Group 1201). As a secondary aim, we investigated the rate of allelic imbalance between germline and tumor DNA.

Methods

Eighty-one eligible treatment-naïve subjects with newly diagnosed resectable esophageal adenocarcinoma received radiotherapy (45 Gy) concurrent with cisplatin-based chemotherapy, with planned subsequent surgical resection. The primary endpoint was pCR, defined as complete absence of tumor in the surgical specimen after radiochemotherapy. Using germline DNA from 60 subjects, we examined the base-excision repair SNP, XRCC1 Arg399Gln, and 4 other SNPs in nucleotide excision (XPD Lys751Gln and Asp312Asn, ERCC1 3' flank) and double-stranded break (XRCC2 5' flank) repair pathways, and correlated genotype with pCR rate. Paired tumor tissue was used to estimate the frequency of allelic imbalance at the XRCC1 SNP.

Results

The variant allele of the XRCC1 SNP (399Gln) was detected in 52% of subjects. Only 6% of subjects with the variant allele experienced a pCR, compared to 28% of subjects without the variant allele (odds ratio 5.37 for failing to achieve pCR, p = 0.062). Allelic imbalance at this locus was found in only 10% of informative subjects, suggesting that germline genotype may reflect tumor genotype at this locus. No significant association with pCR was noted for other SNPs.

Conclusions

Assessed for the first time in a prospective, interventional trial cohort of esophageal adenocarcinoma, XRCC1 399Gln was associated with resistance to radiochemotherapy. Further investigation of this genetic variation is warranted in larger cohorts. In addition, these data indicate that germline genotype may serve as a surrogate for tumor genotype at this locus.

XPD Lys751Gln polymorphism and esophageal cancer risk: A meta-analysis involving 2288 cases and 4096 controls

AIM: To evaluate the association between xeroderma pigmentosum group D (XPD), genetic polymorphism Lys751Gln and esophageal cancer risk.

METHODS: We searched PubMed up to September 1, 2010 to identify eligible studies. A total of 10 case-control studies including 2288 cases and 4096 controls were included in the meta-analysis. Statistical analysis was performed with Review Manage version 4.2. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association.

RESULTS: The results suggested that there is no significant association between XPD Lys751Gln polymorphism and esophageal cancer susceptibility in the overall population. However, in subgroup analysis by histology type, a significant association was found between XPD Lys751Gln polymorphism and esophageal adenocarcinoma (for CC vs AA: OR = 1.25, 95% CI = 1.01-1.55, P = 0.05 for heterogeneity).

CONCLUSION: Our meta-analysis suggested that XPD Lys751Gln polymorphism may be associated with increased risk of esophageal adenocarcinoma.

hOGG1 Ser326Cys polymorphism and risk of childhood acute lymphoblastic leukemia in a Chinese population

Oxidative DNA damage caused by reactive oxygen species can produce 8-oxoguanine (8-oxoG) in DNA, which is misread and leads to G:C→T:A transversions. This can be carcinogenic. Repair of 8-oxoG by the base excision repair pathway involves the activity of human 8-oxoG DNA glycosylase 1 (hOGG1). Accumulating evidence suggests that the hOGG1 Ser326Cys polymorphism affects the activity of hOGG1 and might serve as a genetic marker for susceptibility to several cancers. To determine whether this polymorphism is associated with risk of childhood acute lymphoblastic leukemia (ALL) in Chinese children, we genotyped the hOGG1 Ser326Cys polymorphism (rs1052133) in a case-control study including 415 cases and 511 controls. We found that there was a significant difference in the genotype distributions of the hOGG1 Ser326Cys polymorphism between cases and controls (P = 0.046), and the combined genotypes Ser/Ser and Ser/Cys were associated with a statistically significantly decreased risk of ALL (adjusted odds ratio [OR] = 0.66, 95% confidence interval [CI] = 0.49-0.88, P = 0.005). Furthermore, we found a decreased risk for high risk ALL (adjusted OR = 0.60, 95% CI = 0.40-0.88, P = 0.005), low risk ALL (adjusted OR = 0.68, 95% CI = 0.47-0.99, P = 0.042), and B-phenotype ALL (adjusted OR = 0.63, 95% CI = 0.46-0.86, P = 0.003) among children with the Ser/Ser and Ser/Cys genotypes. Our results suggest that the hOGG1 Ser326Cys polymorphism is associated with susceptibility to childhood ALL in a Chinese population.

OGG1 Ser326Cys polymorphism and susceptibility to esophageal cancer in low and high at-risk populations of northern India

BACKGROUND

Esophageal cancer has diverse incidence worldwide, and genetic/environmental risk factors are supposed to be responsible for it. OGG1 Ser326Cys gene polymorphism (rs1052133) has been found to be associated with different cancer susceptibilities and interaction with different environmental factors.

AIM OF THE STUDY

The aim of this study is to detect the role of OGG1 Ser326Cys polymorphism in susceptibility to esophageal cancer in two Northern Indian populations having different incidence rates.

METHODS

A total of 737 cases and controls from two high and low at-risk populations were selected for the study. All the subjects were genotyped by PCR with confronting two-pair primers.

RESULTS

No significant association was found between OGG1 Ser326Cys genotypes and esophageal cancer risk in both of the populations. Gene-environment analysis revealed no significant interaction between OGG1 Ser326Cys genotypes and smoking/high-salted tea intake habits.

CONCLUSION

OGG1 Ser326Cys polymorphism does not have a role in determining susceptibility to esophageal cancer either in high or in low at-risk populations of Northern India.

MUTYH Tyr165Cys, OGG1 Ser326Cys and XPD Lys751Gln polymorphisms and head neck cancer susceptibility: a case control study

In the present study we investigated the association between three polymorphisms of the MUTYH (Tyr165Cys, rs34612342), the OGG1 (Ser326Cys, rs1052133) and the XPD (Lys751Gln, rs13181) genes with head and neck cancer risk. Genotypes were determined in DNA from peripheral blood lymphocytes of 265 patients with head and neck squamous cell carcinoma (HNSCC) as well as 280 cancer-free controls by PCR-restriction fragment length polymorphisms. We found an association between HNSCC and the Ser326Cys (OR 1.69; 95% CI 1.19-2.45) as well as Cys326Cys (OR 4.56; 95% CI 2.07-10.05) variants of the OGG1 gene. The gene-gene interaction between MUTYH and OGG1 as well as OGG1 and XPD polymorphic variants may contribute to higher prevalence of HNSCC. We also found an association between Ser326Cys and Cys326Cys variants of OGG1 gene and smoking status in HNSCC patients (OR 1.97; 95% CI 1.25-3.11), (OR 3.54; 95% CI 1.39-9.04), respectively. Moreover, we also observed a protective association between Tyr165Cys variant of the MUTYH gene and non-smoking status in HNSCC (OR 0.34; 95% CI 0.17-0.66). We also found a link between gene-gene interaction (MUTYH and OGG1 or OGG1 and XPD) and smoking (ORs 2.17-4.20 and 2.18-5.23) or non-smoking status (ORs 0.11 and 7.61) in HNSCC patients, respectively. In conclusion our data showed that the Ser326Cys polymorphism of the OGG1 gene may modify the risk of HNSCC associated with smoking. Finally we suggested that this polymorphism might be used as predictive factor for head and neck cancer in Polish population.

The role of oxidative DNA damage, DNA repair, GSTM1, SOD2 and OGG1 polymorphisms in individual susceptibility to Barrett’s esophagus

Determination of the genetic alterations, which play a role in the etiology of Barrett’s esophagus (BE), could help identify high-risk individuals for esophageal adenocarcinoma (EA). The aim of the present study was to investigate the role of oxidative DNA damage, glutathione (GSH) concentration as oxidative stress parameters and DNA repair capacity, GSTM1, SOD1 Ala16Val and OGG1 Ser326Cys genetic polymorphisms as individual susceptibility parameters in the etiology of BE. The study groups comprised BE patients who were clinically diagnosed (n = 40) and a healthy control group (n = 40). Basal DNA damage, pyrimidine and purine base damage after H2O2 induction, H 2O2 sensitivity, DNA repair capacity, oxidized pyrimidine and purine base damage repair were evaluated in peripheral blood lymphocytes with a modified comet assay using specific endonucleases (Endo III and Fpg). Polymerase chain reaction—restriction length polymorphism (PCR-RFLP)-based assays were used for genotyping. The patient group showed elevated levels of basal DNA damage, pyrimidine base damage and H2O2 sensitivity as compared to controls (p < .05). DNA repair capacity, oxidized pyrimidine and purine base damage repair capacity, were not statistically different between patients and controls. GSH concentration was found to be significantly lower in smoking patients than in the controls (p < .05). None of the genetic variations changed the risk of having BE disease. However, patients carrying the variant OGG1 Cys allele showed elevated levels of pyrimidine base damage as compared to patients carrying the wild-type OGG1 Ser (p < .05). The results of this study point to a role of oxidative DNA damage in BE. However, DNA repair capacity, GSTM1, SOD1 Ala16Val and OGG1 Ser326Cys genetic polymorphisms appeared to play no role in the individual susceptibility to this disease.

Dissecting GI phenotype-genotype relationships in GERD and dyspepsia: an SNP here and an SNP there!

It is known that the predisposition to human disease is a mixture of inherited susceptibility and acquired exposure to environmental factors. Understanding gastrointestinal disease has indicated that germline adenomatous polyposis coli mutations predispose with a 99% certainty to colorectal cancer, whereas squamous esophageal cancer is caused by a combination of environmental exposures (including alcohol consumption, cigarette smoke, ingestion of contaminated preserved food) and/or infection (specifically with human papilloma virus), in most cases. Until now, despite the reasonably strong evidence for genetic risk from monozygotic twin studies for gastro-esophageal reflux disease (GERD), there have been no documented genetic targets in GERD. In this edition of the Journal, there is intriguing evidence that a common, single base-pair change in the secondary messenger gene GNbeta3 (i.e., a single-nucleotide polymorphism) may be important, perhaps through promoting abnormal perception of visceral pain in the esophagus. Other works link this genetic factor to functional dyspepsia, and these exciting preliminary lines of evidence are reviewed.