Polymorphisms of XPG/ERCC5 and risk of squamous cell carcinoma of the head and neck

Haplotypes of single cancer driver genes and their local ancestry in a highly admixed long-lived population of Northeast Brazil

Admixed populations have not been examined in detail in cancer genetic studies. Here, we inferred the local ancestry of cancer-associated single nucleotide polymorphisms (SNPs) and haplotypes of a highly admixed Brazilian population. SNP array was used to genotype 73 unrelated individuals aged 80-102 years. Local ancestry inference was performed by merging genotyped regions with phase three data from the 1000 Genomes Project Consortium using RFmix. The average ancestry tract length was 9.12-81.71 megabases. Strong linkage disequilibrium was detected in 48 haplotypes containing 35 SNPs in 10 cancer driver genes. All together, 19 risk and eight protective alleles were identified in 23 out of 48 haplotypes. Homozygous individuals were mainly of European ancestry, whereas heterozygotes had at least one Native American and one African ancestry tract. Native-American ancestry for homozygous individuals with risk alleles for HNF1B, CDH1, and BRCA1 was inferred for the first time. Results indicated that analysis of SNP polymorphism in the present admixed population has a high potential to identify new ancestry-associated alleles and haplotypes that modify cancer susceptibility differentially in distinct human populations. Future case-control studies with populations with a complex history of admixture could help elucidate ancestry-associated biological differences in cancer incidence and therapeutic outcomes.

Thyroid Cancer: The Quest for Genetic Susceptibility Involving DNA Repair Genes

The incidence of thyroid cancer (TC), particularly well-differentiated forms (DTC), has been rising and remains the highest among endocrine malignancies. Although ionizing radiation (IR) is well established on DTC aetiology, other environmental and genetic factors may also be involved. DNA repair single nucleotide polymorphisms (SNPs) could be among the former, helping in explaining the high incidence. To further clarify the role of DNA repair SNPs in DTC susceptibility, we analyzed 36 SNPs in 27 DNA repair genes in a population of 106 DTCs and corresponding controls with the aim of interpreting joint data from previously studied isolated SNPs in DNA repair genes. Significant associations with DTC susceptibility were observed for XRCC3 rs861539, XPC rs2228001, CCNH rs2230641, MSH6 rs1042821 and ERCC5 rs2227869 and for a haplotype block on chromosome 5q. From 595 SNP-SNP combinations tested and 114 showing relevance, 15 significant SNP combinations (p < 0.01) were detected on paired SNP analysis, most of which involving CCNH rs2230641 and mismatch repair variants. Overall, a gene-dosage effect between the number of risk genotypes and DTC predisposition was observed. In spite of the volume of data presented, new studies are sought to provide an interpretability of the role of SNPs in DNA repair genes and their combinations in DTC susceptibility.

Diagnostic and prognostic values of the mRNA expression of excision repair cross-complementation enzymes in hepatitis B virus-related hepatocellular carcinoma

Background

The current study aims at using the whole genome expression profile chips for systematically investigating the diagnostic and prognostic values of excision repair cross-complementation (ERCC) genes in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC).

Materials and methods

Whole genome expression profile chips were obtained from the GSE14520. The receiver-operating characteristic (ROC) curve, survival analysis, and nomogram were used to investigate the diagnostic and prognostic values of ERCC genes. Investigation of the potential function of ERCC8 was carried out by gene set enrichment analysis (GSEA) and genome-wide coexpression analysis.

Results

ROC analysis suggests that six ERCC genes (ERCC1, ERCC2, ERCC3, ERCC4, ERCC5, and ERCC8) were dysregulated and may have potential to distinguish between HBV-related HCC tumor and paracancerous tissues (area under the curve of ROC ranged from 0.623 to 0.744). Survival analysis demonstrated that high ERCC8 expression was associated with a significantly decreased risk of recurrence (adjusted P=0.021; HR=0.643; 95% CI=0.442–0.937) and death (adjusted P=0.049; HR=0.631; 95% CI=0.399–0.998) in HBV-related HCC. Then, we also developed two nomograms for the HBV-related HCC individualized prognosis predictions. GSEA suggests that the high expression of ERCC8 may have involvement in the energy metabolism biological processes. As the genome-wide coexpression analysis and functional assessment of ERCC8 suggest, those coexpressed genes were significantly enriched in multiple biological processes of DNA damage and repair.

Conclusion

The present study indicates that six ERCC genes (ERCC1, ERCC2, ERCC3, ERCC4, ERCC5, and ERCC8) were dysregulated between HBV-related HCC tumor and paracancerous tissues and that the mRNA expression of ERCC8 may serve as a potential biomarker for the HBV-related HCC prognosis.

XPG rs873601 G>A contributes to uterine leiomyoma susceptibility in a Southern Chinese population

XPG gene contributes to DNA repair defects and genomic instability, which may lead to the initiation of uterine leiomyoma. We hypothesized that genetic variants of XPG gene may alter the carriers' susceptibility to leiomyoma. The association between five potential functional single nucleotide polymorphisms (SNPs), i.e. rs2094258 C>T, rs751402 C>T, rs2296147 T>C, rs1047768 T>C, rs873601 G>A, and uterine leiomyoma risk in Chinese, was investigated in this case-control study, which included 398 incident leiomyoma cases and 733 controls. We found that rs873601 was significantly associated with tumor risk in a recessive genetic model after being adjusting for age and menopause. When compared with rs873601 GG/GA genotypes, the AA genotype had an increased leiomyoma risk (adjusted OR = 1.59, 95% CI = 1.16-2.18, P=0.004; Bonferroni adjusted P=0.040). Furthermore, stratified analysis revealed that the association between the rs873601 AA genotype and leiomyoma risk was more evident among subjects younger than 40 years old (adjusted OR = 1.58, 95% CI = 1.06-2.35, P=0.023) and patients who had more than three myomas (adjusted OR = 2.05, 95% CI = 1.24-3.41, P=0.006). Yet, no significant association between the other four polymorphisms and leiomyoma risk was observed. To sum up, the present study reported on the association between XPG gene polymorphisms and myoma risk. The observed data indicated that SNP rs873601 G>A contributes to uterine leiomyoma susceptibility in a Southern Chinese population.

XPG rs17655 G>C polymorphism associated with cancer risk: evidence from 60 studies

Xeroderma pigmentosum group G (XPG), a key component in nucleotide excision repair pathway, functions to cut DNA lesions during DNA repair. Genetic variations that alter DNA repair gene expression or function may decrease DNA repair ability and impair genome integrity, thereby predisposing to cancer. The association between XPG rs17655 G>C polymorphism and cancer risk has been investigated extensively, but the results remain contradictory. To get a more accurate conclusion, we performed a comprehensive meta-analysis of 60 case-control studies, involving 27,098 cancer cases and 30,535 healthy controls. Crude odds ratios (ORs) and 95% confidence interval (CIs) were calculated to determine the association of interest. Pooled analysis indicated that the XPG rs17655 G>C polymorphism increased the risk of overall cancer (CC vs. GG: OR=1.10, 95% CI=1.00-1.20; CG vs. GG: OR=1.06, 95% CI=1.02-1.11; CG+CC vs. GG: OR=1.07, 95% CI=1.02-1.12; C vs. G: OR=1.05, 95% CI=1.01-1.09). Stratification analysis by cancer type further showed that this polymorphism was associated with increased risk of gastric cancer and colorectal cancer. This meta-analysis indicated that the XPG gene rs17655 G>C polymorphism was associated with increased overall cancer risk, especially the risk of gastric cancer and colorectal cancer. Further validation experiments are needed to strength our conclusion.

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.

Chinese C allele carriers of the ERCC5 rs1047768 polymorphism are more sensitive to platinum-based chemotherapy: a meta-analysis

It is suspected that ERCC5 rs1047768 and rs17655 polymorphisms influence the response to platinum-based chemotherapy. This meta-analysis was performed to summarize the scattered evidence regarding the association between these two polymorphisms and sensitivity to platinum-based treatment. Thirteen studies were included after a comprehensive literature search. The pooled odds ratios and 95% confidence intervals suggested that the C allele of the ERCC5 rs1047768 polymorphism is associated with elevated sensitivity to platinating agents, especially for Chinese patients. However, no difference among rs17655 genotypes could be detected.

Mechanisms underlying the antiproliferative effects of a series of quinoxaline-derived chalcones

The present study aimed to characterize the effects of quinoxaline-derived chalcones, designed on the basis of the selective PI3Kγ inhibitor AS605240, in oral cancer cells. Three lead compounds, namely N9, N17 and N23, were selected from a series of 20 quinoxaline-derived chalcones, based on an initial screening using human and rat squamous cell carcinoma lineages, representing compounds with at least one methoxy radical at the A-ring. The selected chalcones, mainly N9 and N17, displayed marked antiproliferative effects, via apoptosis and autophagy induction, with an increase of sub-G1 population and Akt inhibition. The three chalcones displayed marked in vitro antitumor effects in different protocols with standard chemotherapy drugs, with acceptable toxicity on normal cells. There was no growth retrieval, after exposure to chalcone N9 alone, in a long-term assay to determine the cumulative population doubling (CPD) of human oral cancer cells. A PCR array evaluating 168 genes related to cancer and inflammation, demonstrated striking actions for N9, which altered the expression of 74 genes. Altogether, our results point out quinoxalinic chalcones, mainly N9, as potential strategies for oral cancer treatment.

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.

Reduced mRNA expression of nucleotide excision repair genes in lymphocytes and risk of squamous cell carcinoma of the head and neck

Nucleotide excision repair (NER) plays a critical role in the development of smoking-related cancers. We hypothesize that mRNA expression levels of NER genes are associated with risk of the squamous cell carcinoma of head and neck (SCCHN). To test this hypothesis, we conducted a case-control study of 260 SCCHN patients and 246 cancer-free controls by measuring the mRNA expression levels of eight core NER genes in cultured peripheral lymphocytes. Compared with the controls, cases had statistically significantly lower expression levels of DDB1 and ERCC3 (P = 0.015 and 0.041, respectively). Because DDB1 and ERCC3 expression levels were highly correlated, we used DDB1 for further multivariate analyses and modeling. After dividing the subjects by controls' quartiles of expression levels, we found an association between an increased risk of SCCHN and low DDB1 expression levels [adjusted ORs and 95% CIs: 1.92 and 1.11-3.32, 1.48 and 0.85-2.59, 2.00 and 1.15-3.45 for the 2nd-4th quartiles, respectively, compared with the 1st quartile; Ptrend = 0.026]. We also identified a multiplicative interaction between sex and DDB1 expression levels (P = 0.007). Finally, the expanded model with gene expression levels, in addition to demographic and clinical variables, on SCCHN risk was significantly improved, especially among men. In conclusion, reduced DDB1 expression levels were associated with an increased risk of SCCHN. However, these results need to be validated in larger studies.

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.

XPG Gene Polymorphisms Contribute to Colorectal Cancer Susceptibility: A Two-Stage Case-Control Study

Previous studies have reported that xeroderma pigmentosum group G (XPG) gene polymorphisms may modulate colorectal cancer (CRC) susceptibility. In this study, we performed a two-stage case-control study to comprehensively investigate the associations of five polymorphisms in the XPG gene with CRC risk in 1,901 cases and 1,976 controls from Southern China, including rs2094258 C>T, rs751402 C>T, rs2296147 T>C, rs1047768 T>C and rs873601 G>A. After combining data from two stages, we found that three of the studied polymorphisms (rs2094258 C>T, rs751402 C>T, and rs873601 G>A) were significantly associated with CRC susceptibility. After adjustment for age and gender, multivariate logistic regression analysis indicated that carriers of the rs2094258 T alleles had an increased CRC risk [CT vs. CC: adjusted odds ratio (OR)=1.17, 95% confidence interval (CI)=1.01-1.36; TT vs. CC: adjusted OR=1.49, 95% CI=1.18-1.89; TT vs. CT/CC: adjusted OR=1.38, 95% CI=1.10-1.72]. Likely, rs873601 A allele also conferred increased CRC susceptibility. In contrast, a protective association was identified between rs751402 C>T polymorphism and the risk of CRC. In summary, our results indicated that these three polymorphisms were found to associate with CRC susceptibility in a Southern Chinese population.

XPG Gene Polymorphisms and the Risk of Gastric Cardia Adenocarcinoma

BACKGROUND

Polymorphisms in DNA repair genes can alter an individual's DNA repair capability and contribute to the risk of various cancers.

AIMS

This study was designed to evaluate the association of single-nucleotide polymorphisms (SNPs) in the XPG gene with the risk of gastric cardia adenocarcinoma (GCA) in a high-incidence population in northern China.

METHODS

Two SNPs from 431 GCA patients and 432 healthy controls were genotyped using the polymerase chain reaction/ligase detection reaction (PCR-LDR) method.

RESULTS

The rs751402 C/T SNP T allele and the T/T genotype were associated with an increased risk of GCA in younger individuals (≤61 years) (odds ratio [OR] = 1.33 and 1.77, 95% confidence interval [CI] = 1.00-1.76 and 1.12-3.30, respectively). The rs873601 G/A SNP was not associated with susceptibility to GCA.

CONCLUSIONS

Our findings indicate that the rs751402 C/T SNP has potential as a predictive marker for the risk of GCA and that carriers of the T/T genotype should receive periodic upper gastrointestinal fiber tests to facilitate the early detection and early treatment of GCA.

Prediction role of seven SNPs of DNA repair genes for survival of gastric cancer patients receiving chemotherapy

We aimed to investigate DNA repair gene expression of response to chemotherapy among gastric patients, and roles in the prognosis of gastric cancer. A total of 209 gastric cancer patients were included in this study between January 2007 and December 2008, all treated with chemotherapy. Polymorphisms were detected by real time PCR with TaqMan probes, and genomic DNA was extracted from peripheral blood samples. The overall response rate was 61.2%. The median progression and overall survivals were 8.5 and 18.7 months, respectively. A significant increased treatment response was found among patients with XPG C/T+T/T or XRCC1 399G/ A+A/A genotypes, with the OR (95% CI) of 2.14 (1.15-4.01) and 1.75 (1.04-3.35) respectively. We found XPG C/T+T/T and XRCC1 399 G/A+A/A were associated with a longer survival among gastric cancer patients when compared with their wide type genotypes, with HRs and 95% CIs of 0.49 (0.27-0.89) and 0.56 (0.29-0.98) respectively. Selecting specific chemotherapy based on pretreatment genotyping may be an innovative strategy for further studies.

Genetic Association between the XPG Asp1104His Polymorphism and Head and Neck Cancer Susceptibility: Evidence Based on a Meta-Analysis

BACKGROUND

Previous studies evaluating the association between the xeroderma pigmentosum group G (XPG) Asp1104His polymorphism and head and neck cancer susceptibility have proven controversial. This meta-analysis of the literature was performed to obtain a more precise estimation of the relationship.

MATERIALS AND METHODS

We systematically searched PubMed, Embase and Web of Science with a time limit of Dec 18, 2014. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of any association.

RESULTS

We performed a meta-analysis of eight published case-control studies, including 3,621 cases and 5,475 controls. Overall, no significant association was found between the XPG Asp1104His polymorphism and head and neck cancer susceptibility under all genetic models. In the subgroup analysis by ethnicity, the XPG Asp1104His polymorphism had statistically significant association with elevated head and neck cancer risk under CC vs GG (OR=1.24, 95% CI=1.00~1.54) and the recessive model (OR=1.22, 95%CI=1.01~1.46) in Asian populations. A similar result was found under CC vs GG (OR =1.22, 95%CI =1.01~1.47) in the population based subgroup by source of control. When performed by tumor site, the XPG Asp1104His polymorphism had statistically significant association with elevated laryngeal cancer under all genetic models (CC vs GG: OR=1.59, 95% CI=1.16~2.19; GC vs GG: OR=1.38, 95%CI=1.10~1.72; dominant model: OR=1.42, 95% CI=1.15~1.74; recessive model: OR=1.36, 95% CI=1.02~1.81).

CONCLUSIONS

This meta-analysis suggested that the XPG Asp1104His polymorphism is a risk factor for head and neck cancer susceptibility, especially for laryngeal cancer and in Asian populations.

SNPs of excision repair cross complementing group 5 and gastric cancer risk in Chinese populations

We conducted a case-control study to determine the association between several potential SNPs of excision repair cross complementing group 5 (XPG) and gastric cancer susceptibility, and roles of XPG polymorphisms in combination with H.pylori infection in determining risk of gastric cancer. In our study, we collected 337 newly diagnosed gastric cancer cases and 347 health controls. Three SNPs of XPG, rs2296147T>C, rs2094258C>T and rs873601G>A, were genotyped using the Taqman real-time PCR method with a 7900 HT sequence detector system. H. pylori infection was diagnosed by ELISA. By multivariate logistic regression analysis, the rs2296147 CC genotype was associated with a decreased risk of gastric cancer (OR=0.52, 95% CI=0.27-0.97), and rs2094258 TT was associated with elevated risk (OR=2.13, 95% CI=1.22-3.35). Positive H.pylori individuals with rs2094258 TT genotypes demonstrated increased risk of gastric cancer (OR=2.13, 95% CI=1.22-3.35), while rs2296147 CC was associated with lower risk among patients with negative H.pylori (OR=0.45, 95%CI=0.22-0.89). Our findings suggested that XPG polymorphisms might contribute to risk of gastric cancer among Chinese populations, but the effect needs to be further validated by larger sample size studies.

Polymorphisms in nucleotide excision repair genes and basal cell carcinoma of the skin

BACKGROUND

Mutations in nucleotide excision repair (NER) genes are the cause of xeroderma pigmentosum, a genetic syndrome with proneness to basal cell carcinoma (BCC) of the skin. Single nucleotide polymorphisms (SNPs) may affect the effectiveness of DNA repair and hence influence individual susceptibility to a variety of neoplasms. The aim of this study was to find associations between SNPs in selected NER genes and sporadic BCC development.

MATERIALS AND METHODS

The study group consisted of 100 patients with histopathologically confirmed BCCs and the control group of 100 elderly individuals with no personal history of any cancer. DNA isolated from peripheral blood lymphocytes was genotyped for seven SNPs in five different NER genes. Statistical analyses for associations were performed.

RESULTS

A weak association between XPD exon 6 silent C/A polymorphism and BCC development risk was found when comparing single polymorphisms between the two groups. When considering sex and SNPs, men with the A-allele in XPC intron 11 C/A have been found to have a decreased risk of BCC.

CONCLUSIONS

There is no consistency in association studies between SNPs and BCC susceptibility. SNPs in NER genes seem to have an insignificant influence on the risk of developing BCC of the skin.

Association between the XPG Asp1104His and XPF Arg415Gln polymorphisms and risk of cancer: a meta-analysis

BACKGROUND

The XPG (xeroderma pigmentosum type G) Asp1104His and XPF (xeroderma pigmentosum type F) Arg415Gln polymorphisms had been implicated in cancer susceptibility. The previous published data on the association between XPG Asp1104His and XPF Arg415Gln polymorphisms and cancer risk remained controversial.

METHODOLOGY/PRINCIPAL FINDINGS

To derive a more precise estimation of the association between the XPG Asp1104His and XPF Arg415Gln polymorphisms and overall cancer risk, we performed a meta-analysis to investigate the association between cancer susceptibility and XPG Asp1104His (32,162 cases and 39,858 controls from 66 studies) and XPF Arg415Gln polymorphisms (17,864 cases and 20,578 controls from 32 studies) in different inheritance models. We used odds ratios with 95% confidence intervals to assess the strength of the association. Overall, significantly elevated cancer risk was found when all studies were pooled into the meta-analysis of XPG Asp1104His (dominant model: OR = 1.05, 95% CI = 1.00-1.10; Asp/His vs. Asp/Asp: OR = 1.06, 95% CI = 1.01-1.11). In the further stratified and sensitivity analyses, significantly decreased lung cancer risk was found for XPF Arg415Gln (dominant model: OR = 0.82, 95% CI = 0.71-0.96; Arg/Gln versus Arg/Arg: OR = 0.83, 95% CI = 0.71-0.97; additive model: OR = 0.83, 95% CI = 0.72-0.95) and significantly increased other cancer risk was found among hospital-based studies for XPG Asp1104His (dominant model: OR = 1.23, 95% CI = 1.02-1.49).

CONCLUSIONS/SIGNIFICANCE

In summary, this meta-analysis suggests that XPF Arg415Gln polymorphism may be associated with decreased lung cancer risk and XPG Asp1104His may be a low-penetrant risk factor in some cancers development. And larger scale primary studies are required to further evaluate the interaction of XPG Asp1104His and XPF Arg415Gln polymorphisms and cancer risk in specific populations.

Genetic association between ERCC5 rs17655 polymorphism and lung cancer risk: evidence based on a meta-analysis

The relationship between excision repair cross-complementing group 5 (ERCC5) rs17655 polymorphism and lung cancer risk remains controversial. To clarify the association, we conducted a comprehensive meta-analysis of all published case-control studies. PubMed, Web of Science, and CNKI were searched to identify the possibly eligible publications. Pooled odds ratio (OR) was estimated using the fixed effect model. Q test and I (2) index were used to evaluate heterogeneity between studies, and Egger's and Begg's tests were utilized to assess publication bias. Meta-analysis of nine case-control studies including 4,044 cases and 5,100 controls indicated that there was no global association between rs17655 polymorphism and lung cancer risk. Subgroup analyses according to ethnicity and histologic type revealed similar results. In summary, our meta-analysis suggests that ERCC5 rs17655 polymorphism may not contribute to genetic susceptibility for lung cancer.

Single-nucleotide polymorphisms in nucleotide excision repair genes, cigarette smoking, and the risk of head and neck cancer

BACKGROUND

Cigarette smoking is associated with increased head and neck cancer (HNC) risk. Tobacco-related carcinogens are known to cause bulky DNA adducts. Nucleotide excision repair (NER) genes encode enzymes that remove adducts and may be independently associated with HNC, as well as modifiers of the association between smoking and HNC.

METHODS

Using population-based case-control data from the Carolina Head and Neck Cancer Epidemiology (CHANCE) Study (1,227 cases and 1,325 controls), race-stratified (White, African American), conventional, and hierarchical logistic regression models were used to estimate ORs with 95% intervals (I) for the independent and joint effects of cigarette smoking and 84 single-nucleotide polymorphisms (SNP) from 15 NER genes on HNC risk.

RESULTS

The odds of HNC were elevated among ever cigarette smokers and increased with smoking duration and frequency. Among Whites, rs4150403 on ERCC3 was associated with increased HNC odds (AA+AG vs. GG; OR, 1.28; 95% CI, 1.01-1.61). Among African Americans, rs4253132 on ERCC6 was associated with decreased HNC odds (CC+CT vs. TT; OR, 0.62; 95% CI, 0.45-0.86). Interactions between ever cigarette smoking and three SNPs (rs4253132 on ERCC6, rs2291120 on DDB2, and rs744154 on ERCC4) suggested possible departures from additivity among Whites.

CONCLUSIONS

We did not find associations between some previously studied NER variants and HNC. We did identify new associations between two SNPs and HNC and three suggestive cigarette-SNP interactions to consider in future studies.

IMPACT

We conducted one of the most comprehensive evaluations of NER variants, identifying a few SNPs from biologically plausible candidate genes associated with HNC and possibly interacting with cigarette smoking.

Association between the ERCC5 Asp1104His polymorphism and cancer risk: a meta-analysis

BACKGROUND

Excision repair cross complementing group 5 (ERCC5 or XPG) plays an important role in regulating DNA excision repair, removal of bulky lesions caused by environmental chemicals or UV light. Mutations in this gene cause a rare autosomal recessive syndrome, and its functional single nucleotide polymorphisms (SNPs) may alter DNA repair capacity phenotype and cancer risk. However, a series of epidemiological studies on the association between the ERCC5 Asp1104His polymorphism (rs17655, G>C) and cancer susceptibility generated conflicting results.

METHODOLOGY/PRINCIPAL FINDINGS

To derive a more precise estimation of the association between the ERCC5 Asp1104His polymorphism and overall cancer risk, we performed a meta-analysis of 44 published case-control studies, in which a total of 23,490 cases and 27,168 controls were included. To provide additional biological plausibility, we also assessed the genotype-gene expression correlation from the HapMap phase II release 23 data with 270 individuals from 4 ethnic populations. When all studies were pooled, we found no statistical evidence for a significantly increased cancer risk in the recessive genetic models (His/His vs. Asp/Asp: OR = 0.99, 95% CI: 0.92-1.06, P = 0.242 for heterogeneity or His/His vs. Asp/His + Asp/Asp: OR = 0.98, 95% CI: 0.93-1.03, P = 0.260 for heterogeneity), nor in further stratified analyses by cancer type, ethnicity, source of controls and sample size. In the genotype-phenotype correlation analysis from 270 individuals, we consistently found no significant correlation of the Asp1104His polymorphism with ERCC5 mRNA expression.

CONCLUSIONS/SIGNIFICANCE

This meta-analysis suggests that it is unlikely that the ERCC5 Asp1104His polymorphism may contribute to individual susceptibility to cancer risk.

Polymorphisms in the ERCC5 gene and risk of esophageal squamous cell carcinoma (ESCC) in Eastern Chinese populations

BACKGROUND

Excision repair cross complementing group 5 (ERCC5 or XPG) plays an important role in regulating DNA excision repair; its functional single nucleotide polymorphisms (SNPs) may alter DNA repair capacity and thus contribute to cancer risk.

METHODOLOGY/PRINCIPAL FINDINGS

In a hospital-based case-control study of 1115 esophageal squamous cell carcinoma (ESCC) cases and 1117 cancer-free controls, we genotyped three potentially functional SNPs of ERCC5 (SNPs, rs2296147T>C, rs2094258C>T and rs873601G>A) and estimated crude and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for their associations with risk of ESCC using unconditional logistic regression models. We also calculated false-positive report probabilities (FPRPs) for significant findings. We found that compared with the TT genotype, ERCC5 rs2296147 C variant genotypes were associated with a significantly lower ESCC risk (CT: adjusted OR = 0.76, 95% CI = 0.63-0.93, CT/CC: adjusted OR = 0.80, 95% CI = 0.67-0.96); however, this risk was not observed for the other two SNPs (rs2094258C>T and rs873601 G>A), nor in further stratification and haplotype analysis.

CONCLUSIONS/SIGNIFICANCES

These findings suggested that ERCC5 polymorphisms may contribute to risk of ESCC in Eastern Chinese populations, but the effect was weak and needs further validation by larger population-based case-control studies.