XPG Gene Polymorphisms and the Risk of Gastric Cardia Adenocarcinoma

One stomach, two subtypes of carcinoma—the differences between distal and proximal gastric cancer

Gastric cancer (GC) is one of the most common malignant tumors of the digestive tract, posing a significant risk to human health. Over the past 10 years, the pathological characteristics and the prognosis of GC have been determined based on the locations of the tumors that were then classified into two types—proximal and distal GC. This review focuses on the differences in epidemiology, etiology, cell source, pathological characteristics, gene expression, molecular markers, manifestations, treatment, prognosis, and prevention between proximal and distal GC to provide guidance and a basis for clinical diagnosis and treatment.

XPG gene polymorphisms and glioma susceptibility: a two-centre case-control study

Background: Glioma, the most common tumour in children next to leukaemia, is difficult to treat, with a poor prognosis and high recurrence rate. Xeroderma pigmentosum group G (XPG) plays a key role in the nucleotide excision repair pathway, which may modulate individual susceptibility to developing cancer. We hypothesized links between XPG variants and glioma in children.Methods: We tested our hypothesis in a study comparing 171 glioma cases with 228 age and sex matched controls, determining XPG polymorphisms rs2094258 C > T, rs751402 C > T, rs2296147 T > C, rs1047768 T > C, rs873601 G > A by standard molecular genetic methods.Results: rs2094258 C > T was associated with a decreased glioma risk, but carrying the rs1047768 C or rs873601 A allele brought an increased risk. Subjects carrying 5 risk genotypes had a significantly increased glioma risk at an adjusted odds ratio of 1.97 (95% confidence Interval 1.26-3.08)(p = 0.003) when compared with those carrying 0-4 risk genotypes. Furthermore, children with 5 risk genotypes had a higher glioma risk when aged >60 months, were more likely to be male, and with subtypes of astrocytic tumours, and low-grade clinical stage, when compared to those with 0-4 risk genotypes. Preliminary functional exploration suggested that rs2094258 is linked with the expression of its surrounding genes in the expression quantitative trait locus analysis.Conclusion: Certain variants of XPG are risk factors for paediatric glioma, and so may be useful in early diagnosis.

Risk factors predisposing to cardia gastric adenocarcinoma: Insights and new perspectives

Recent decades have seen an alarming increase in the incidence of cardia gastric adenocarcinoma (CGA) while noncardia gastric adenocarcinoma (NCGA) has decreased. In 2012, 260 000 CGA cases (age‐standardised rate (ASR); 3.3/100 000) and 691 000 NCGA cases (ASR; 8.8/100 000) were reported worldwide. Compared with women, men had greater rates for both the subsites, especially for CGA. Recently, four molecular subtypes of GC have been proposed by the Cancer Genome Atlas (TCGA) and the Asian Cancer Research Group (ACRG); however, these classifications do not take into account predisposing germline variants and their possible interaction with somatic alterations in carcinogenesis. The etiology of adenocarcinoma of the cardia and the gastroesophageal junction (GEJ) is not known. It is thought that CGA is distinct from adenocarcinomas located in the esophagus or distal stomach, both epidemiologically and biologically. Moreover, CGA is often identified in the advanced stage having a poor prognosis. Therefore, understanding the risk and the role of predisposing factors in etiology of CGA can inform clinical practice and counseling for risk reduction. In this paper, we showed that GC family history, lifestyle, demographics, gastroesophageal reflux disease, Helicobacter pylori infection, and multiple genetic and epigenetic risk factors as well as several predisposing conditions may underlie susceptibility to CGA. However, several genome‐wide association studies (GWASs) should be conducted to identify novel high‐penetrance genes and pathways as well as causal germline variants predisposing to CGA. They must include different ethnic groups, especially from high‐incidence countries for CGA, because some risk loci are ancestry‐specific. In parallel, statistical methods can be developed to identify cancer predisposition genes (CPGs) from tumor sequencing data. It is also necessary to find novel long noncoding RNAs related to the risk of CGA. Taken altogether, new cancer risk prediction models, including all genetic and nongenetic factors influencing risk, should be developed to facilitate risk assessment, disease prevention, and early diagnosis and intervention of CGA in the future.

XPG gene polymorphisms and cancer susceptibility: evidence from 47 studies

Xeroderma pigmentosum group G (XPG) is a single-strand-specific DNA endonuclease that functions in the nucleotide excision repair pathway. Genetic variations in XPG gene can alter the DNA repair capacity of this enzyme. We evaluated the associations between six single nucleotide polymorphisms (SNPs) in XPG (rs1047768 T>C, rs2296147 T>C, rs2227869 G>C, rs2094258 C>T, rs751402 C>T, and rs873601 G>A) and cancer risk. Forty-seven studies were identified in searches of the PubMed, Scopus, Web of Science, China National Knowledge Infrastructure, and WanFang databases. Crude odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a fixed or random effects model. We found that rs873601 G>A was associated with an increased overall cancer risk (AA vs. GG: OR = 1.14, 95% CI = 1.06–1.24; GA/AA vs. GG: OR = 1.08, 95% CI = 1.02–1.15; A vs. G: OR = 1.06, 95% CI = 1.02–1.10). In a stratified analysis, rs1047768 T>C was associated with an increased risk of lung cancer, rs2227869 G>C was associated with a decreased risk of cancer in population-based studies, and rs751402 C>T and rs873601 G>A were associated with the risk of gastric cancer. Our data indicate that rs873601 G>A is associated with cancer susceptibility.

Association between Polymorphisms of ERCC5 Gene and Susceptibility to Gastric Cancer: A Systematic Review and Meta-Analysis

Background:

several epidemiological studies have suggested that polymorphisms of the Excision Repair Cross Complementing Group-5 (ERCC5) gene might be related to gastric cancer risk; however, the results have been inconsistent or controversial. Therefore, we have performed a systematic review and meta-analysis to clarify the association between the ERCC5 gene polymorphisms and gastric cancer risk.

Materials and Methods:

An electronic search was conducted of several databases, including PubMed, Web of Science, and Google Scholar for articles that describe the association between polymorphisms of the ERCC5 gene and susceptibility of gastric cancer.

Results:

A total of 33 case control studies in 15 publications were included in the present meta-analysis. There were significant associations between gastric cancer susceptibility and ERCC5 gene rs751402 C>T (T vs. C: OR = 1.166, 95% C = 1.066-1.274, p= 0.001; TT vs. CC: OR = 0.723, 95% CI = 0.587-0.890, p = 0.002; TT+TC vs. CC: OR = 0.853, 95% CI = 0.757-0.961, p = 0.009; TT vs. TC+CC: OR = 0.793, 95% CI = 0.659-0.955, p = 0.015), rs2296147 T>C (C vs. T: OR = 1.268, 95% C = 1.049-1.532, p= 0.014), rs873601 G>A polymorphisms (A vs. G, OR = 1.087, 95% C = 1.021-1.159, p= 0.010; AA vs. GG, OR = 1.184, 95% CI = 1.043-1.343, p = 0.009, AA vs. AG+GG, OR = 1.156, 95% CI = 1.040-1.284, p = 0.007), but not rs2094258 C>T and rs1047768 T>C.

Conclusion:

the current meta-analysis demonstrates that rs751402 C>T, rs2296147 T>C, and rs873601 G>A polymorphisms of ERCC5 gene are associated with the susceptibility of gastric cancer.

Association between the polymorphisms in XPG gene and gastric cancer susceptibility in Chinese populations: A PRISMA-compliant meta-analysis

BACKGROUND

Several previous studies were carried out on the association between xeroderma pigmentosum group G (XPG) gene polymorphisms (including rs873601 G>A, rs2094258 C>T, rs2296147 T>C, and rs751402 C>T) and the risk of gastric cancer in Chinese populations. However, their conclusions were not consistent. Therefore, this meta-analysis was performed by us to investigate the association between the 4 potentially functional single nucleotide polymorphisms (SNPs) of XPG gene and gastric cancer risk.

METHODS

The eligible literatures were identified through PubMed, Embase, Ovid MEDLINE, Web of Science, CNKI, and Wan fang databases up to July 2017. Finally, 5 studies for rs873601, 7 studies for rs2094258, 4 studies for rs2296147, and 8 studies for rs751402 were used for the current meta-analysis.

RESULTS

Of the 4 included SNPs, only rs751402 was showed to be associated with the risk of gastric cancer [C vs T, odds ratio (OR) = 1.16, 95% confidence interval (CI) = 1.04-1.29; CC + CT vs TT, OR = 1.23, 95% CI = 1.00-1.52; CC vs CT + TT, OR = 1.15, 95% CI = 1.05-1.27; CC vs TT, OR = 1.35, 95% CI = 1.06-1.72; CC vs CT, OR = 1.13, 95% CI = 1.02-1.25].

CONCLUSION

The current meta-analysis demonstrated that the XPG gene polymorphism rs751402 was associated with increased susceptibility to gastric cancer in Chinese populations. However, studies with a larger number of subjects among different ethnic groups are needed to further validate the results.

Association of XPG gene rs751402 polymorphism with gastric cancer risk: a meta-analysis in the Chinese population

BACKGROUND

Previous studies have revealed a conflicting relationship of xeroderma pigmentosum group G (XPG) gene polymorphism with gastric cancer (GC) risk. To our knowledge, this is the first meta-analysis to investigate the association between rs751402 mutation located on the XPG promoter region and GC risk.

METHODS

We undertook a meta-analysis by identifying relevant articles from the PubMed, Web of Science and China National Knowledge Infrastructure (CNKI) databases on February 28, 2017. By pooling 9 eligible studies, 3,539 GC cases and 3,948 controls were included. The pooled odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated using the fixed-effects or random-effects model depending on the existence of heterogeneity across studies. The population attributable risk (PAR%) was estimated to better understand the public health risk.

RESULTS

All included studies had been conducted in China. Significant associations were found between the XPG rs751402 polymorphism and the risk of GC (TT vs. CC: OR = 1.43, 95% CI, 1.11-1.84; CT vs. CC: OR = 1.15, 95% CI, 1.04-1.26; dominant model: OR = 1.17, 95% CI, 1.07-1.29; recessive model: OR = 1.30, 95% CI, 1.05-1.62; T vs. C: OR = 1.18, 95% CI, 1.06-1.32). The estimated PAR% was about 4.9%-8.8%. Funnel plots did not reveal any potential publication bias. The sensitivity analyses showed that the results were relatively robust.

CONCLUSIONS

This meta-analysis indicates that the XPG rs751402 polymorphism may be a risk factor for GC in the Chinese population.

The Association Between XPG Gene Polymorphism and Gastric Cancer Risk

PURPOSE

Studies exploring the association between the Xeroderma pigmentosum group G (XPG) gene polymorphisms and gastric cancer (GC) risk provide conflicting findings. Thus, this meta-analysis was performed.

MATERIALS AND METHODS

The PubMed and EMBASE databases were comprehensively searched to identify studies for the inclusion in the meta-analysis. The strength of the association was evaluated by calculating pooled odds ratios and 95% confidence intervals.

RESULTS

Nine case-control studies involving 3540 cases and 3953 controls were included in the meta-analysis, which revealed that the XPG rs751402 polymorphism is positively associated with GC risk and could be viewed as a risk factor of GC in three genetic models.

CONCLUSION

The XPG gene rs751402 polymorphism is associated with an increased risk of GC in Chinese Han populations. This finding should be verified by larger studies that include additional ethnic groups.

XPG gene rs751402 C>T polymorphism and cancer risk: Evidence from 22 publications

The Xeroderma pigmentosum group G (XPG) gene promotes recognition and excision of damaged DNA during the DNA repair process. We conducted a comprehensive search of the MEDLINE, EMBASE, and Chinese Biomedical databases for publications evaluating the association XPG gene rs751402 C>T polymorphism and overall cancer risk. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were adopted to assess the strength of the association. A total of 22 publications encompassing 10538 cases and 10511 control subjects were included in the final meta-analysis. We found the polymorphism to be associated with increased cancer risk (TT vs. CC: OR = 1.18, 95% CI = 1.01-1.38, P = 0.040; CT vs. CC: OR = 1.12, 95% CI = 1.01-1.24, P = 0.040; and CT/TT vs. CC: OR = 1.12, 95% CI = 1.002-1.26, P = 0.045). Stratification by cancer type indicated that this polymorphism may increase the risk of gastric cancer and hepatocellular carcinoma, which was further confirmed by a false-positive report probability analysis. Genotype-based mRNA expression provides further evidence that this polymorphism is associated with altered XPG mRNA expression. This meta-analysis suggests XPG gene rs751402 C>T polymorphism correlates with overall cancer risk, especially for gastric cancer and hepatocellular carcinoma.

The association between XPG polymorphisms and cancer susceptibility: Evidence from observational studies

BACKGROUND

Exposure to environmental carcinogens can cause damages to DNA. If not properly repaired, the DNA damages may increase the risk of carcinogenesis. Xeroderma pigmentosum group G (XPG) gene is an essential gene in the nucleotide excision repair (NER) pathway. The association between XPG polymorphisms and cancer susceptibility has been the focus of attention in the molecular epidemiology of cancer. However, the conclusions have been divergent. Therefore, we conducted a comprehensive meta-analysis to precisely evaluate the association of 3 frequently investigated XPG polymorphisms (rs751402, rs873601, and rs2296147) with cancer risk.

METHODS

Pubmed, EMBASE, and Chinese National Knowledge Infrastructure (CNKI) were searched for relevant studies in English and Chinese. Odds ratio (OR) and 95% confidence interval (CI) were used to assess the association between XPG polymorphisms (rs751402, rs873601, and rs2296147) and cancer risk.

RESULTS

Twenty-three studies were included. Overall, there was no significant association between rs751402 polymorphism and overall cancer risk under the 5 gene models. However, we observed strong correlation between rs751402 polymorphism and gastric cancer (C vs T: OR=1.21, 95% CI = 1.00-1.26, P = .045; TC vs CC: OR = 1.12, 95% CI = 1.00-1.24, P = .041; TC/TT vs CC: OR = 1.13, 95% CI = 1.02-1.26, P = .020). There was a significant correlation between rs873601 polymorphism and cancer risk under the homozygous model (GG vs AA: OR = 1.16, 95% CI = 1.07-1.26, P = .001). Moreover, significant association with breast cancer was detected for rs873601 polymorphism under the allele contrast model (G vs A: OR = 1.10, 95% CI = 1.02-1.20, P = .021). In the subgroup of Asian, rs873601 polymorphism was related to the susceptibility to cancer (G vs A: OR = 1.07, 95% CI = 1.03-1.12, P = .010; GG vs AA: OR = 1.15, 95% CI = 1.06-1.26, P = .001; AG/AA vs GG: OR = 1.08, 95% CI = 1.01-1.15, P = .031; AA vs AG/GG: OR = 1.13, 95% CI = 1.05-1.21, P = .001). Significant association between rs2296147 polymorphism and cancer risk were observed in Asian population (CT vs TT: OR = 0.93, 95% CI = 0.87-0.99, P = .036).

CONCLUSIONS

Our meta-analysis suggested that the rs873601 polymorphism was significantly associated with overall cancer risk. The moderate effects of rs751402 and rs2296147 polymorphism on cancer susceptibility might be highly dependent on cancer type and ethnicity, respectively. Large studies are needed to validate our findings, especially in Caucasian and African population.