Xeroderma Pigmentosum Group D Asp312Asn Polymorphism Research Articles

The relationship between XPD Asp312Asn Polymorphism and esophageal cancer in Chinese population: a meta-analysis

It has been reported that xeroderma pigmentosum group D (XPD) Asp312Asn is related to esophageal cancer (EC). Nevertheless, in 12 recent years, some researchers have put forward different points of view. Thus, we aimed to investigate the relation between XPD Asp312Asn polymorphism and the risk of EC in Chinese. Related studies were searched in the databases between the beginning to October 2019. An OR with 14 the corresponding 95% CI was carried out to appraise the relevance. There were 8 studies with 2553 esophageal cancer cases and 3091 controls in 15 this meta-analysis. Due to no heterogeneities among the selected studies of all the four genetic models, fxed-effect model was used in each genotype. There was not significant relationship between XPD Asp312Asn polymorphism and EC in overall analyses by pooled ORs and subgroup analyses stratified by geographic area and source of controls. In conclusion, there may be not association between XPD Asp312Asn polymorphism and EC in Chinese populations. Further studies about other ethnic groups are needed to confirm this conclusion.

Association of XPD Asp312Asn polymorphism and response to oxaliplatin-based first-line chemotherapy and survival in patients with metastatic colorectal cancer.

Identification of biomarkers predicting a response to chemotherapeutic drugs would greatly ease the selection of personalized therapy. The protein xeroderma pigmentosum group D (XPD) functions in nucleotide excision repair (NER) to remove DNA cross-links and in the regulation of transcription. The potential role of the Asp312Asn polymorphism in predicting the response to chemotherapy has not been established. This prospective study was designed to determine the role of the XPD Asp312Asn polymorphism in predicting the response to oxaliplatin-based first-line chemotherapy and survival in patients with metastatic colorectal cancer. A total of 106 patients treated with 2 cycles of either FOLFOX4 (n = 72) or XELOX (n = 34) regimen as the chemotherapy were enrolled. The genotype of XPD Asp312Asn polymorphism was analyzed using TaqMan probe-based real-time polymerase chain reaction (PCR). Logistic regression was applied to predict the response to treatment protocols. Cox regression models were applied to predict overall survival. The overall response to chemotherapy was 57.6% (61/106). FOLFOX4 and XELOX regimens demonstrated comparable efficacy. The XPD Asp312Asn polymorphism was not associated with the response to either FOLFOX4 or XELOX regimen in univariate and in multivariate logistic regression analyses. Levels of carcinoembryonic antigen (CEA) ≥5 ng/mL and female gender were associated with a lack of response to FOLFOX4, but not to XELOX regimen. In a multivariate survival analysis, XPD Asp312Asn AA genotype, lack of response to chemotherapy, CEA ≥ 5 ng/mL, and age ≥65 were significantly associated with worse overall survival. The XPD Asp312Asn polymorphism is associated with overall survival, but it is not a biomarker in predicting the response to oxaliplatin-based first-line chemotherapy in patients with metastatic colorectal cancer.

Association Between XPD Lys751Gln and Asp312Asn Polymorphisms and Hepatocellular Carcinoma Risk

Genetic polymorphisms of xeroderma pigmentosum group D (XPD) in the nucleotide excision repair pathway may influence cancer susceptibility by affecting the capacity for DNA repair. Studies investigating the association between XPD Lys751Gln and Asp312Asn polymorphisms and hepatocellular carcinoma (HCC) risk reported inconsistent results. The aim of this study was to quantitatively summarize the evidence for such an association.Eligible studies were identified by searching electronic databases including PubMed, Embase, Cochrane library, and CBM, Chinese Biomedical Literature Database, for the period up to October 2014. The association of XPD Lys751Gln and Asp312Asn polymorphisms and HCC risk was assessed by odds ratios (ORs) together with their 95% confidence intervals (CIs).Finally, a total of 11 studies with 4322 cases and 4970 controls were included for XPD Lys751Gln polymorphism and 6 studies with 2223 cases and 2441 controls were available for XPD Asp312Asn polymorphism. With respect to XPD Lys751Gln polymorphism, statistically significant increased HCC risk was found when all studies were pooled into the meta-analysis (Gln/Gln vs Lys/Lys: OR = 1.363, 95% CI 1.065–1.744, P = 0.014; Lys/Gln vs Lys/Lys: OR = 1.205, 95% CI 1.099–1.321, P = 0.000; Gln/Gln+Lys/Gln vs Lys/Lys: OR = 1.300, 95% CI 1.141–1.480, P = 0.000). In subgroup analyses by ethnicity, source of control, Hardy–Weinberg equilibrium (HWE) in controls, hepatitis B virus (HBV) infection, and statistically significant increase of HCC risk was found in East Asians, population-based studies, studies consistent with HWE, and HBV-positive subjects, but not in mixed/other populations, hospital-based studies, studies deviating from HWE, and HBV-negative subjects. With respect to XPD Asp312Asn polymorphism, no significant association with HCC risk was found in the overall and subgroup analyses.The results suggest that the XPD Lys751Gln polymorphism contributes to increased HCC susceptibility, especially in East Asian populations. Further, large and well-designed studies are required to validate this association.

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

To clarify the effects of the xeroderma pigmentosum group D (XPD) Asp312Asn and Lys751Gln gene polymorphisms on the risk of esophageal cancer (EC). 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. 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). The results of this meta-analysis suggest that the XPD Asp312Asn and Lys751Gln gene polymorphisms are associated with a significantly increased risk for EC.

Genetic polymorphisms of xeroderma pigmentosum group D gene Asp312Asn and Lys751Gln and susceptibility to prostate cancer: A systematic review and meta-analysis

Many studies have reported the role of xeroderma pigmentosum group D (XPD) with prostate cancer risk, but the results remained controversial. To derive a more precise estimation of the relationship, a meta-analysis was performed. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association between XPD Asp312Asn and Lys751Gln polymorphisms and prostate cancer risk. A total of 8 studies including 2620 cases and 3225 controls described Asp312Asn genotypes, among which 10 articles involving 3230 cases and 3582 controls described Lys751Gln genotypes and were also involved in this meta-analysis. When all the eligible studies were pooled into this meta-analysis, a significant association between prostate cancer risk and XPD Asp312Asn polymorphism was found. For Asp312Asn polymorphism, in the stratified analysis by ethnicity and source of controls, prostate cancer risk was observed in co-dominant, dominant and recessive models, while no evidence of any associations of XPD Lys751Gln polymorphism with prostate cancer was found in the overall or subgroup analyses. Our meta-analysis supports that the XPD Asp312Asn polymorphism contributed to the risk of prostate cancer from currently available evidence. However, a study with a larger sample size is needed to further evaluate gene–environment interaction on XPD Asp312Asn and Lys751Gln polymorphisms and prostate cancer risk.

Predictive Value of XPD Polymorphisms on Platinum-Based Chemotherapy in Non-Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

BackgroundThe correlation between xeroderma pigmentosum group D (XPD) polymorphisms (Lys751Gln and Asp312Asn) and clinical outcomes of non-small cell lung cancer (NSCLC) patients, who received platinum-based chemotherapy (Pt-chemotherapy), is still inconclusive. This meta-analysis was aimed to systematically review published evidence and ascertain the exact role of XPD polymorphisms.MethodsDatabases of MEDLINE and EMBASE were searched up to April 2013 to identify eligible studies. A rigorous quality assessment of eligible studies was conducted according the Newcastle-Ottawa Quality Assessment Scales. The relationship between XPD polymorphisms and response to Pt-chemotherapy and survival was analyzed.ResultsA total of 22 eligible studies were included and analyzed in this meta-analysis. The overall analysis suggested that the XPD Lys751Gln polymorphism was not associated with response to Pt-chemotherapy or survival. However, the XPD 312Asn allele was significantly associated with poor response to Pt-chemotherapy compared with the Asp312 allele (Asn vs. Asp: OR = 0.435, 95% CI: 0.261–0.726). Additionally, the variant genotype of XPD Asp312Asn polymorphism was associated with favorable survival in Caucasian (AspAsn vs. AspAsp: HR = 0.781, 95% CI: 0.619–0.986) but unfavorable survival in Asian (AspAsn+AsnAsn vs. AspAsp: HR = 1.550, 95% CI: 1.038–2.315).ConclusionsThese results suggest that XPD Asp312Asn polymorphism may function as a predictive biomarker on platinum-based chemotherapy in NSCLC and further studies are warranted.

XPD Lys751Gln and Asp312Asn Polymorphisms and Gastric Cancer Susceptibility: A Meta-analysis of Case-control Studies

Published data regarding the association between xeroderma pigmentosum group D (XPD) Lys751Gln and Asp312Asn polymorphisms and gastric cancer susceptibility havew been inconclusive. This meta-analysis was therefore performed toobtain a more precise estimation of any relationship. A comprehensive literature search was conducted to identify all case-control studies of Lys751Gln and Asp312Asn polymorphisms and susceptibility to gastric cancer. Summary odds ratios (ORs) and its 95% confidence intervals (95% CIs) were calculated using a random-effects model with the software STATA (version10.0). A total of 12 case-control studies including 3,147 cases and 4,736 controls were included. Overall, no significant associations were found in some models (for Lys751Gln: Lys/Gln vs Lys/Lys: OR=1.144, 95% CI=0.851-1.541, Gln/Gln vs Lys/Lys: OR=1.215, 95% CI = 0.740-1.955, dominant model: OR=1.137, 95% CI=0.818-1.582; recessive model: OR=1.123, 95% CI=0.765-1.650; for Asp312Asn: Asp/Asn vs Asp/Asp: OR=1.180, 95% CI=0.646-2.154, dominant model: OR=1.380, 95% CI = 0.812-2.346), but significantly elevated susceptibility was found for Asp312Asn polymorphism in some models (Asn/Asn vs Asp/Asp: OR=2.045, 95% CI=1.254-3.335, recessive model: OR=1.805, 95% CI =1.219-2.672 ), for the additive model, the XPD Lys751Gln and Asp312Asn polymorphisms were not significantly associated with gastric cancer susceptibility. In stratified analyses, significantly elevated susceptibility was found for some models in the Chinese population. This meta-analysis suggested the XPD Asp312Asn polymorphism might be a potential biomarker of gastric cancer susceptibility in overall population, while both XPD Lys751Gln and Asp312Asn polymorphisms might be risk factors of gastric cancer susceptibility in Chinese.

The Effect of XPD/ERCC2 Polymorphisms on Gastric Cancer Risk among Different Ethnicities: A Systematic Review and Meta-Analysis

BackgroundPotential xeroderma pigmentosum group D (XPD), also called excision repair cross-complimentary group two (ERCC2), Lys751Gln and Asp312Asn polymorphisms have been implicated in gastric cancer risk among different ethnicities.MethodsWe aimed to explore the effect of XPD Lys751Gln and Asp312Asn polymorphisms on the susceptibility to gastric cancer among different ethnicities through a systematic review and meta-analysis. Each initially included article was scored for quality appraisal. Desirable data were extracted and registered into databases. 13 studies were ultimately eligible for the meta-analysis of Lys751Gln polymorphism and 9 studies for the meta-analysis of Asp312Asn polymorphism. We adopted the most probably appropriate genetic model (recessive model) for both Lys751Gln and Asp312Asn polymorphisms. Potential sources of heterogeneity were sought out via subgroup and sensitivity analyses, and publication biases were estimated.ResultsStatistically significant findings were apparently noted in Asians but not in Caucasians for both XPD Lys751Gln and XPD Asp312Asn polymorphisms. A statistically significant finding could be seen in noncardia-type gastric cancer for XPD Lys751Gln polymorphism. A statistically significant finding could also be seen in high quality subgroup, small-and-moderate sample size subgroup, articles published after 2007, or PCR-RFLP genotyping subgroup for XPD Asp312Asn polymorphism.ConclusionsOur meta-analysis indicates that XPD Gln751Gln (CC) genotype and Asn312Asn (AA) genotype may seem to be more susceptible to gastric cancer in Asian populations but not in Caucasian populations, suggesting that the two genotypes may be important biomarkers of gastric cancer susceptibility for Asian populations, the assumption that needs to be further confirmed in well-designed studies among different ethnicities. Gln751Gln (CC) genotype may also be associated with noncardia-type gastric cancer risk, which should also be confirmed among different ethnicities in the future.

Association Between XPD Asp312Asn Polymorphism and Esophageal Cancer Susceptibility: A Meta-analysis

To investigate the association between xeroderma pigmentosum group D (XPD) Asp312Asn polymorphism and esophageal cancer (EC) susceptibility by meta-analysis. We searched PubMed up to April 9th, 2012, to identify relevant papers, and 8 published case-control studies including 2165 EC patients and 3141 healthy controls were yielded. Odds ratios (ORs) with relevant 95% confidence intervals (CIs) were applied to assess the association between XPD Asp312Asn polymorphism and EC susceptibility with the Comprehensive Meta-Analysis software, version 2.2. Overall, the meta-analysis results suggested the XPD Asp312Asn polymorphism to be significantly associated with EC susceptibility [(Asn/Asn+Asp/Asn) vs. Asp/Asp: OR=1.20, 95%CI=1.05-1.36, p=0.01; and Asp/Asn vs. Asp/Asp: OR=1.15, 95%CI=1.01-1.31, p=0.04]. In the subgroup analysis by ethnicity and cancer type, significantly associations were found for Caucasian populations [(Asn/Asn+Asp/Asn) vs. Asp/Asp: OR=1.26, 95%CI=1.08-1.47, p<0.001; Asp/Asn vs. Asp/Asp: OR=1.19, 95%CI=1.02- 1.40, p=0.03] and esophageal squamous cell carcinoma [(Asn/Asn+Asp/Asn) vs. Asp/Asp: OR=1.19, 95%CI=1.01-1.41, p=0.04]. There was no heterogeneity and no publication bias existed. This meta-analysis shows that the XPD Asp312Asn polymorphism may be a risk factor for developing EC, especially for Caucasian populations and esophageal squamous cell carcinoma.

XPD Asp312Asn polymorphism is a risk factor for prostate cancer

The association between Asp312Asn and Lys751Gln polymorphisms of Xeroderma pigmentosum Group D (XPD) and prostate cancer risk are still inconclusive. For better understanding of the effects of these two polymorphisms on prostate cancer risk, a meta-analysis was performed. An extensive search was performed to identify all case-control studies investigating such association. The strength of association between these two polymorphisms and prostate cancer risk was assessed by odds ratio (OR) with the corresponding 95 % confidence interval (95 % CI). A total of seven case-control studies were identified, among which five studies (1,257 cases and 1,956 controls) were eligible for Asp312Asn polymorphism and six studies (1,451 cases and 2,375 controls) were eligible for Lys751Gln polymorphism. Asp312Asn polymorphism was associated with an increased risk of prostate cancer in additive and recessive genetic models (additive model: OR = 1.68, 95 % CI = 1.28-2.22, P = 0.00; recessive model: OR = 1.65, 95 % CI = 1.27-2.15, P = 0.00). In the subgroup analysis, Asp312Asn polymorphism was associated with an increased risk of prostate cancer among Asians in all three genetic models (additive model: OR = 2.09, 95 % CI = 1.39-3.14, P = 0.00; dominant model: OR = 1.49, 95 % CI = 1.12-1.98, P = 0.01; recessive model: OR = 1.93, 95 % CI = 1.31-2.83, P = 0.00). However, no significant associations were found between Lys751Gln polymorphism and prostate cancer risk in the overall analyses or the subgroup analyses by ethnicity. The results of this meta-analysis indicate that the XPD Asp312Asn polymorphism is a risk factor for prostate cancer development.

Impact of DNA repair genes polymorphism (XPD and XRCC1) on the risk of breast cancer in Egyptian female patients

The genes involved in DNA repair system play a crucial role in the protection against mutations. It has been hypothesized that functional deficiencies in highly conserved DNA repair processes resulting from polymorphic variation may increase genetic susceptibility to breast cancer (BC). The aim of the present study was to evaluate the association of genetic polymorphisms in 2 DNA repair genes, XPD (Asp312Asn) and XRCC1 (A399G), with BC susceptibility. We further investigated the potential combined effect of these DNA repair variants on BC risk. Both XPD (xeroderma pigmentosum group D) and XRCC1 (X-ray repair cross-complementing group 1) polymorphisms were characterized in 100 BC Egyptian females and 100 healthy women who had no history of any malignancy by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) method and PCR with confronting two-pair primers (PCR-CTPP), using DNA from peripheral blood in a case control study. Our results revealed that the frequencies of AA genotype of XPD codon 312 polymorphism were significantly higher in the BC patients than in the normal individuals (P ≤ 0.003), and did not observe any association between the XRCC1 Arg399Gln polymorphism and risk of developing BC. Also, no association between both XPD Asp312Asn and XRCC1 A399G polymorphisms and the clinical characteristics of disease. Finally, the combination of AA(XPD) + AG(XRCC1) were significantly associated with BC risk. Our results suggested that, XPD gene is an important candidate gene for susceptibility to BC. Also, gene-gene interaction between XPD(AA) + XRCC1(AG) polymorphism may be associated with increased risk of BC in Egyptian women.

Lack of association between XPD Lys751Gln and Asp312Asn polymorphisms and colorectal cancer risk: a meta-analysis of case–control studies

The published data on the association between xeroderma pigmentosum group D (XPD) Lys751Gln and Asp312Asn polymorphisms and colorectal cancer 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 and Asp312Asn polymorphisms on the susceptibility of different tumor site of colorectal cancer (colon, rectum, and colon/rectum cancer). A total of 22 eligible studies were selected for this meta-analysis, including 3,042 cases and 4,627 controls for Lys751Gln and 1,581 cases and 2,846 controls for Asp312Asn. Overall, no significantly elevated colorectal cancer risk was found in all genetic models when all studies were pooled into the meta-analysis (for Lys751Gln polymorphism: Lys/Gln vs. Lys/Lys, OR = 1.01, 95% CI = 0.90-1.14; Gln/Gln vs. Lys/Lys, OR = 1.04, 95% CI = 0.85-1.26; dominant model, OR = 1.03, 95% CI = 0.93-1.15; recessive model, OR = 1.04, 95% CI = 0.87-1.25; and for Asp312Asn polymorphism: Asp/Asn vs. Asp/Asp, OR = 1.11, 95% CI = 0.91-1.35; Asn/Asn vs. Asp/Asp, OR = 1.13, 95% CI = 0.87-1.47; dominant model, OR = 1.09, 95% CI = 0.94-1.26; recessive model, OR = 1.11, 95% CI = 0.88-1.41). And for the additive model, individuals carrying the 751Gln or 312Asn allele were not significantly associated with increased risk to colorectal cancer (OR = 1.02, 95% CI = 0.94-1.11, OR = 1.07, 95% CI = 0.95-1.20). This meta-analysis suggests that XPD Lys751Gln and Asp312Asn polymorphisms may not be associated with colorectal cancer development.

The association between XPD Asp312Asn polymorphism and lung cancer risk: a meta-analysis including 16,949 subjects

To derive a more precise estimation of the relationship between the xeroderma pigmentosum group D (XPD) Asp312Asn polymorphism and lung cancer risk, a meta-analysis was performed. PubMed, Medline, Embase, and Web of Science were searched. Crude ORs with 95% CIs were used to assess the strength of association between the XPD Asp312Asn polymorphism and lung cancer risk. The pooled ORs were performed with co-dominant model (Asp/Asn vs. Asp/Asp, Asn/Asn vs. Asp/Asp), dominant model (Asp/Asn + Asn/Asn vs. Asp/Asp), and recessive model (Asn/Asn vs. Asp/Asp+Asp/Asn), respectively. A total of 18 studies including 7,552 cases and 9,397 controls were involved in this meta-analysis. Overall, significantly elevated lung cancer risk was associated with XPD Asn allele when all studies were pooled into the meta-analysis (Asn/Asn vs. Asp/Asp: OR=1.158, 95% CI=1.018-1.317; recessive model: OR=1.161, 95% CI=1.029-1.311). In the subgroup analysis by ethnicity, significantly increased risks were found for both Caucasians (Asn/Asn vs. Asp/Asp: OR=1.164, 95% CI=1.003-1.351; recessive model: OR=1.169, 95% CI=1.016-1.345) and Asians (Asn/Asn vs. Asp/Asp: OR=8.056, 95% CI=2.420-26.817; recessive model: OR=7.956, 95% CI=2.391-26.477). When stratified by study design, statistically significantly elevated risk was noted in hospital-based studies (Asn/Asn vs. Asp/Asp: OR=1.315, 95% CI=1.110-1.558; recessive model: OR=1.290, 95% CI=1.099-1.513). In conclusion, this meta-analysis suggests that the XPD Asn allele is a low-penetrant risk factor for developing lung cancer.

XPD Lys751Gln and Asp312Asn polymorphisms and bladder cancer risk: a meta-analysis

Studies on the polymorphisms of Xeroderma Pigmentosum Group D (XPD) have shown inconclusive trends in the risk of bladder cancer. The purpose of this study is to evaluate the role of XPD single nucleotide polymorphisms in bladder cancer susceptibility. We performed a meta-analysis on all available studies, which included 5,368 and 6,683 XPD Lys(751)Gln cases and controls and 3,220 and 4,391 Asp(312)Asn cases and controls, respectively. Overall, Significant risk effects of Lys(751)Gln genotype was found under recessive model contrast [Gln/Gln vs. (Gln/Lys + Lys/Lys)] [P = 0.04, OR = 1.12; 95% CI (1.01, 1.26)], and subtle but insignificantly increased risks between Lys(751)Gln and bladder cancer were observed under allele contrast (Gln vs. Lys) and homologous contrast (Gln/Gln vs. Lys/Lys) in all subjects. The (751)Gln allele had no significant effect on bladder cancer in all subgroups (Asian, Caucasian and USA). Significant risk effects of Asp(312)Asn polymorphism on bladder susceptibility were observed in all subjects under all genetic contrasts, however, stratified analyses showed that the (312)Asn allele showed different risk effects in USA and Caucasian. The Gln/Gln genotype acts as a risk factor in its association with bladder cancer, and the effect of Lys(751)Gln polymorphism on bladder susceptibility should be studied with larger, stratified population; the (312)Asn allele has an important role in the etiology of bladder cancer whereas the ethnic background should be carefully concerned in further studies.

XRCC1 and XPD polymorphisms and esophageal adenocarcinoma risk

DNA damage is important in the pathogenesis of esophageal adenocarcinoma (EA). Polymorphic variants in DNA repair genes may be modifiers of the risk of EA through their role in altering human host response to gastroesophageal acid reflux, a well-described risk factor for EA. We studied the role of genetic polymorphisms of two key DNA repair genes, xeroderma pigmentosum group D (XPD) (Asp312Asn and Lys751Gln) in the nucleotide excision repair (NER) pathway and X-ray repair cross-complementing gene 1 (XRCC1) (Arg399Gln) in the base excision repair (BER) pathway, in the development of EA in 183 cases and 336 frequency-matched controls for age, gender and race. Genomic DNA was extracted from blood samples. Odds ratios (ORs) and 95% confidence intervals (CIs) were obtained from logistic regression models, adjusted for body mass index at 18 years of age, smoking and alcohol exposure. The variant genotypes of XPD Lys751Gln polymorphism were associated with a higher risk of EA; the adjusted OR comparing Gln/Gln + Lys/Gln with Lys/Lys was 1.49 (95% CI: 1.02-2.14). Although no significant relationships were found for the XRCC1 Arg399Gln polymorphism alone, this polymorphism did modify the relationship between XPD Lys751Gln and EA risk; when both polymorphisms were evaluated together, adding the number of variant alleles of the two polymorphisms resulted in a significant trend (trend test, P = 0.008); compared with individuals with no variant alleles (n = 88), the adjusted ORs of developing EA are 1.49 (95% CI: 0.88-2.59), 1.69 (95% CI: 0.98-2.96) and 2.58 (95% CI: 1.31-5.06) for one (n = 195), two (n = 166) and three or four variant alleles (n = 70), respectively. No relationships were found for the XPD Asp312Asn polymorphism. We conclude that combined NER and BER pathways are important to the development of EA.

ERCC2 /XPD Gene Polymorphisms and Lung Cancer: A HuGE Review

The xeroderma pigmentosum group D (XPD) protein is a well-characterized DNA helicase necessary for the nucleotide excision repair of bulky DNA lesions, such as those induced by cigarette smoking. Polymorphisms in several exons of the XPD gene have been identified; two of them, Asp312Asn and Lys751Gln, are common and result in an amino acid change. Most of the reported data indicate higher levels of DNA adducts in people carrying variant Asn or Gln alleles, which suggests that these persons have lower repair efficiency. These two polymorphisms have been hypothesized to modify the risk of lung cancer. To examine this association, the authors undertook a review and meta-analyses of nine published case-control studies. No clear association between XPD Asp312Asn or XPD Lys751Gln gene polymorphisms and lung cancer was found. However, it may be only the joint effect of multiple polymorphisms within the gene that provides information about an association with lung cancer. Because of advances in high-throughput genotyping techniques, it is likely that future association studies on lung cancer will need to investigate multiple polymorphisms within genes and multiple genes within the same pathway and will need to use recently developed haplotype-based methods to evaluate the haplotypic effects.

Association of the DNA repair gene XPD Asp312Asn polymorphism with p53 gene mutations in tobacco-related non-small cell lung cancer

Lung cancer, a disease related mostly to tobacco smoke exposure and a leading cause of cancer-related death in industrialized countries, is frequently associated with mutations in the p53 tumor suppressor gene. Genetic differences resulting in inter-individual variation in DNA repair capacity may in part account for susceptibility of a cell to genotoxic agents leading to somatic mutations, including p53 mutations, and eventual transformation of a normal cell into a malignant phenotype. The objective of this study is to investigate the relationship between the polymorphisms of two DNA repair genes, the nucleotide excision repair xeroderma pigmentosum group D (XPD) gene (codons 312 and 751) and the base excision repair X-ray repair cross-complementing group 1 (XRCC1) gene (codon 399), and p53 mutations among lung cancer patients. Lung tumors from 204 smokers with non-small cell lung cancer (NSCLC) were analyzed for mutations in exons 5-8 of the p53 gene and genotypes of XPD and XRCC1. p53 mutations were found in 20% (40/204) of the patients. Patients with the XPD codon 312 Asn allele were less likely to have p53 mutations (13.8%) than XPD 312 Asp/Asp (27.3%) [odds ratio (OR) 0.43, 95% confidence interval (CI) 0.20-0.89, P = 0.023]. No association was found between p53 mutations and either XPD Lys751Gln or XRCC1 Arg399Gln. However, the p53 mutation frequency increased with the increased number of the combined genotypes among XPD 312WT (Asp/Asp), XPD 751VT (Lys/Gln or Gln/Gln) or XRCC1 399VT (Arg/Gln or Gln/Gln) (P = 0.01, trend test). These results suggest that individuals who smoke and have the XPD codon 312 Asp/Asp genotype may be at a greater risk of p53 mutations, especially if combined with other polymorphisms that may result in deficient DNA repair.