CYP2E1 RsaI/PstI Polymorphism and Liver Cancer Risk among East Asians: a Huge Review and Meta-analysis

Published data on any association between the CYP2E1 RsaI/PstI (c1/c2) polymorphism and liver cancer riskamong east Asians are inconclusive. The aim of this Human Genome Epidemiology (HuGE) review and metaanalysiswas to derive a more precise estimation of the relationship. A literature search of Pubmed, Embase, Webof science and CBM databases from inception through July 2012 was conducted. Twelve case-control studies wereincluded with a total of 1,552 liver cancer cases and 1,763 healthy controls. Crude odds ratios (ORs) with 95%confidence intervals (CIs) were used to assess the strength of association under five genetic models. When all theeligible studies were pooled into the meta-analysis, the results showed that the c2 allele and the c2 carrier (c2/c2+ c2/c1) of RsaI/PstI polymorphism were associated with decreased risk of liver cancer among east Asians (c2vs. c1: OR = 0.75, 95%CI: 0.59-0.95, P = 0.016; c2/c2 + c2/c1 vs. c1/c1: OR = 0.76, 95%CI: 0.58-1.00, P = 0.050).In the stratified analysis by country, significant associations were observed between RsaI/PstI polymorphismand decreased risk of liver cancer among the Chinese population (c2 vs. c1: OR = 0.70, 95%CI: 0.54-0.91, P =0.007; c2/c2 + c2/c1 vs. c1/c1: OR = 0.72, 95%CI: 0.54-0.95, P = 0.020), but not among Japanese and Koreanpopulations. Results from the current meta-analysis indicates that the c2 allele of CYP2E1 RsaI/PstI (c1/c2)polymorphism may be a protective factor for HCC among east Asians, especially among China populations.     

细胞色素P450 2E1基因多态性与食管癌易感性关系的Meta分析

目的探讨细胞色素P450 2E1（CYP2E1）基因多态性与食管癌易感性的关系。方法检索CBMdisc、CMCC、CNKI、Medline、Pubmed等数据库,并收集未公开发表的文章及硕、博士学位论文,获得有关CYP2E1基因多态性与食管癌易感性的关系的文献进行Meta分析,以病例组及对照组CYP2E1基因型分布的比值比（OR值）为效应指标,确定纳入标准,对文献进行筛选,异质性检验,然后应用Meta分析软件RevMan4．2．2对各研究原始数据进行统计处理,计算合并OR值及95％可信区间。结果按照纳入标准,最终进入系统评价的文献共有11篇病例对照研究,其中食管癌患者1094例,对照1329例,Meta分析结果合并OR=2．61,95％可信区间为1．68—4．05,说明CYP2E1基因型频率分布与食管癌的关联有统计学意义。结论对目前相关研究结果的Meta分析显示,CYP2E1基因多态性与食管癌易感性之间存在相关,即携带Rsa Ⅰ／PstⅠ识别的野生型CYP2E1基因纯合子的个体发生食管癌的危险性较高。     

Cytochrome P450 2E1 RsaI/PstI and DraI polymorphisms are risk factors for lung cancer in Mongolian and Han population in inner Mongolia

Objective: To explore the relationship between cytochrome P450 2E1 (CYP2E1) RsaI/PstI and DraI polymorphism and lung cancer susceptibility in Mongolian and Han population in Inner Mongolia of China. Methods: CYP2E1 RsaI/PstI and DraI polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism in 64 lung cancer patients, 150 healthy Mongolian and 150 healthy Han individuals. The distribution of genotype and allele frequencies of CYP2E1 RsaI/PstI and DraI polymorphisms we...     

Updated Meta-analysis of the Association Between CYP2E1 RsaI/PstI Polymorphisms and Lung Cancer Risk in Chinese Population

Background: A number of studies have reported relationships of CYP2E1 RsaI/PstI polymorphisms with susceptibility to lung cancer in Chinese population. However, the epidemiologic results have been conflictive rather than conclusive. The purpose of this study was to address the associations of CYP2E1 RsaI/PstI polymorphisms with lung cancer risk in Chinese population comprehensively. Materials and Methods: Systematic searches were conducted in the PubMed, Science Direct, Elsevier, CNKI and Chinese Biomedical Literature Databases. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of association. Results: Overall, we observed a decreased lung cancer risk among subjects carrying CYP2E1 RsaI/PstI c1/c2 and c1/c2+c2/c2 genotypes (OR=0.76, 95%CI: 0.64-0.90 and OR=0.78, 95%CI: 0.66-0.93, respectively), as compared with subjects carrying the c1/c1 genotype. In subgroup analysis, we observed a decreased lung cancer risk among c1/c2 carriers in hospital-based studies (OR=0.81, 95%CI: 0.68-0.98) and among carriers with c1/c2 and c1/c2+c2/c2 genotypes in population-based studies(OR=0.57, 95%CI: 0.42-0.79 and OR=0.58, 95%CI: 0.43-0.79, respectively), as compared with subjects carrying the c1/c1 genotype. Limiting the analysis to studies with controls in Hardy-Weinberg equilibrium (HWE), we similarly observed a decreased lung cancer risk among c1/c2 and c1/c2+c2/c2 carriers (OR=0.73, 95%CI: 0.60-0.88 and OR=0.73, 95%CI: 0.60-0.88, respectively), as compared with c1/c1. Conclusions: Our results suggested that CYP2E1 RsaI/PstI c1/c2 and c1/c2+c2/c2 variants might be a protective factor for developing lung cancer in Chinese population. Further well-designed studies with larger sample size are required to verify our findings.     

细胞色素P450 2E1基因多态性与肺癌易感性的研究

目的 :研究与致癌物有关的代谢酶细胞色素P45 0 2E1(CYP 2E1)基因多态性和饮酒与肺癌易感性的关系。方法 :采用聚合酶链反应 (PolymeraseChainReaction ,PCR)和限制性片段长度多态性 (RestrictionFregmentLengthPolymorphisms ,RFLP)方法 ,分析 91例肺癌患者和 138例对照的Rsal认别的CYP 2E1基因型。 结果 :本次研究结果为CYP 2E1基因型频率在肺癌组和对照组的分布差异无显著性意义 (χ2 =1 35 5 ,P >0 0 5 ) ;CYP 2E1C1/C1基因型或饮酒单因素作用的比值比 (OddsRatil,OR)分别为 1 389和 3 33,而两者联合作用的OR为 5 4 1。结论 :CYP 2E1基因多态性与肺癌无明显相关性 ,但与饮酒有联合作用。     

细胞色素P450 2E1基因多态性与肺癌易感性的研究

目的:研究与致癌物有关的代谢酶细胞色素P450 2E1(CYP 2E1)基因多态性和饮酒与肺癌易感性的关系.方法:采用聚合酶链反应(Polymerase Chain Reaction,PCR)和限制性片段长度多态性(Restriction FregmentLength Polymorphisrms,RFLP)方法,分析91例肺癌患者和138例对照的Rsal认别的CYP 2E1基因型.结果:本次研究结果为CYP 2E1基因型频率在肺癌组和对照组的分布差异无显著性意义(X2=1.355,P＞0.05);CYP 2E1C1/C1基因型或饮酒单因素作用的比值比(Odds Ratil,OR)分别为1.389和3.33,而两者联合作用的OR为5.41.结论:CYP 2E1基因多态性与肺癌无明显相关性,但与饮酒有联合作用.     

细胞色素P4502E1基因多态与贲门癌易感性关系探讨

 目的　探讨细胞色素P4 5 0 2E1(CYP2E1)基因多态与贲门癌易感性的关系。方法　采用病例对照研究方法和聚合酶链反应 限制性片段长度多态性 (PCR RFLP)检测技术 ,对 15 9例贲门癌患者和 192例对照的CYP2E1基因多态性进行分析。结果　CYP2E13种基因型在贲门癌病例组和对照组的分布差异有显著性 (χ2 =16 .0 4 ,P <0 .0 1) ,比值OR为 2 .37(95 %CI :1.5 2～ 3.70 )。贲门癌病例组CYP2E1(c1/c1)基因型频率为 6 0 .4 % ,对照组为 4 0 .1%。吸烟且携带CYP2E1(c1/c1)基因型的个体与携带CYP2E1(c1/c2或c2 /c2 )基因型的不吸烟者相比 ,患贲门癌的OR为 4 .6 8(95 %CI:2 .19～ 10 .0 4 )。结论CYP2E1基因多态性与贲门癌易感性有关 ,与吸烟协同作用使贲门癌的危险显著增加     

The Exonuclease 1 Glu589Lys Gene Polymorphism and Cancer Susceptibility: Evidence Based on a Meta-analysis

Background: Published studies on the association between the exonuclease 1 (EXO1) Glu589Lys polymorphismand cancer susceptibility have yielded conflicting results. Thus, a meta-analysis of published studies was performedto assess the possible association. Materials and Methods: All eligible case-control studies published up to January2013 on the association between the EXO1 Glu589Lys polymorphism and cancer susceptibility were identified bysearching PubMed, Web of Science, Science Direct and hand search. Either fixed-effect or random-effect modelswere used to calculate pooled odds ratios (ORs) with 95% confidence intervals (CIs) using the ComprehensiveMeta-Analysis software version 2.2. Results: A total of 4,391 cancer cases and 4,339 controls from 10 studieswere included. Overall, no significant association between the EXO1 Glu589Lys polymorphism and cancersusceptibility was observed in either genetic model. However; in subgroup analyses by cancer type, a significantassociation between EXO1 Glu589Lys and lung cancer risk was found (Lys vs Glu: OR=1.23, 95%CI=1.07-1.41, pheterogeneity=0.05). Further, subgroup analysis by ethnicity indicated that there was a statistically increasedcancer risk in Asians (Lys vs Glu: OR=1.42, 95%CI=1.30-1.55, pheterogeneity=0.07; Lys/Lys vs Glu/Glu: OR=1.93,95%CI=1.20-3.12, pheterogeneity=0.01; Lys/Lys+Glu/Lys vs Glu/Glu: OR=1.52, 95%CI=1.37-1.68, pheterogeneity=0.42;Lys/Lys vs Glu/Lys+Glu/Glu: OR=1.68, 95%CI=1.07-2.65, pheterogeneity=0.02). However, significant association wasabsent in Caucasians. Conclusions: This meta-analysis suggests, for the first time, that the EXO1 Glu589Lyspolymorphism is not associated with overall cancer susceptibility, although marginal associations were found forlung cancer and Asian subgroups. Additional well-designed studies with larger sample size focusing on differentethnicities and cancer types are needed to confirm these findings.     

Association between Restriction Fragment Length Polymorphism of the Human Cytochrome P450IIE1 Gene and Susceptibility to Lung Cancer

Cytochrome P450IIE1 (P450IIE1) is involved in metabolic activation of carcinogenic nitrosamines, aniline and benzene. We detected a restriction fragment length polymorphism of the human P450IIE1 gene with the restriction endonuclease Oral. The population was thus divided into three genotypes, namely, heterozygotes (CD) and two forms of homozygotes (CC and DD). The distribution of these genotypes among lung cancer patients differed front that among controls with statistical significance of P< 0.05 (x²=7.01 with 2 degrees of freedom). This result strongly suggests that host susceptibility to lung cancer is associated with the Dral polymorphism of the P450IIE1 gene.     

The NQO1 rs1800566 Polymorphism and Risk of Bladder Cancer: Evidence from 6,169 Subjects

Objective: The NAD(P)H:quinone oxidoreductase 1 (NQO1) rs1800566 polymorphism, leading to prolinetoserineamino-acid and enzyme activity changes, has been implicated in bladder cancer risk, but individuallypublished studies showed inconsistent results. We therefore here conducted a meta-analysis to summarize thepossible association. Methods: A systematic literature search up to August 27, 2012 was carried out in PubMed,EMBASE and Wanfang databases, and the references of retrieved articles were screened. Crude odds ratios (ORs)with 95% confidence intervals (CIs) were analyzed for homozygote contrast (TT vs. CC), additive model (T vs.C), dominant model (TT+CT vs. CC), and recessive model (TT vs. CC+CT) to assess the association using fixedorrandom-effect models. Results: We identified 12 case-control studies including 3,041 cases and 3,128 controlsfor the present meta-analysis. Significant association between NQO1 rs1800566 genetic polymorphism and riskof bladder cancer was observed in the additive model (OR = 1.15, 95% CI = 1.01-1.30, p = 0.030). Moreover, inthe subgroup analysis stratified by ethnicity, significant associations were observed in Asians (OR = 1.26, 95%CI = 1.08–1.47, p = 0.003 for T vs. C; OR = 1.68, 95% CI = 1.21-2.32, p = 0.002 for TT vs. CC; OR = 1.50, 95%CI = 1.13-1.98, p = 0.005 for TT vs. CT+CC) but not in Caucasians. Conclusions: The results suggest that NQO1rs1800566 genetic polymorphism may contribute to bladder cancer development, especially in Asians.     

Cytochrome P450 1A1, 2E1 and GSTM1 Gene Polymorphisms and Susceptibility to Colorectal Cancer in the Saudi Population

Background: The Saudi population has experienced a sharp increase in colorectal and gastric cancer incidenceswithin the last few years. The relationship between gene polymorphisms of xenobiotic metabolizing enzymesand colorectal cancer (CRC) incidence has not previously investigated among the Saudi population. The aimof the present study was to investigate contributions of CYP1A1, CYP2E1, and GSTM1 gene polymorphisms.Materials and Methods: Blood samples were collected from CRC patients and healthy controls and genotypeswere determined by polymerase chain reaction restriction fragment length polymorphism and sequencing.Results and Conclusions: CYP2E1*6 was not significantly associated with CRC development (odd ratio=1.29;confidence interval 0.68-2.45). A remarkable and statistically significant association was observed amongpatients with CYP1Awt/*2A (odd ratio=3.65; 95% confidence interval 1.39-9.57). The GSTM1*0/*0 genotypewas found in 2% of CRC patients under investigation. The levels of CYP1A1, CYP2E1 and GSTM1 mRNAgene expression were found to be 4, 4.2 and 4.8 fold, respectively, by quantitative real time PCR. The results ofthe present case-control study show that the studied Saudi population resembles Caucasians with respect to theconsidered polymorphisms. Investigation of genetic risk factors and susceptibility gene polymorphisms in ourSaudi population should be helpful for better understanding of CRC etiology.     

细胞色素P450 2E1基因多态与肝癌遗传易感性研究

目的：探讨细胞色素Ｐ４５０ ２Ｅ１基因多态与肝癌的关系。方法：应用ＰＣＲ－ＲＦＬＰ方法对８４例肝癌患者和１４４例健康对照的细胞色素Ｐ４５０ ２Ｅ１基因ＲｓａⅠ多态进行检测。结果：病例组基因型Ａ频率为７１．４３％,等位基因ｃ１频率为８４．５２％,对照组则分别为５５．５６％和７５．３５％,两组差别均有统计学意义（Ｐ〈０．０５）。其比值比分别为２．００和１．７９,提示具有基因型Ａ或等位基因ｃ１的个体患肝     

Association between the CYP1A2 rs762551 Polymorphism and Bladder Cancer Susceptibility: a Meta-Analysis Based on Case-Control Studies

Background: Previous studies evaluated associations between the CYP1A2 rs762551 polymorphism andbladder cancer risk. However, the results were inconsistent. We therefore performed a meta-analysis of thepublished case-control studies to assess in detail the association between CYP1A2 rs762551 polymorphism andbladder cancer risk. Materials and Methods: PubMed, Embase and Web of Science were searched to identifyrelevant studies and the pooled odds ratio (OR) and 95 % confidence interval (95%CI) were calculated. Results:A total of seven articles including 3,013 cases and 2,771 controls were finally included. Overall, a significantassociation was found between the CYP1A2 rs762551 polymorphism and bladder cancer susceptibility for CCvs AA (OR=0.82, 95% CI=0.69~0.99), but no significant associations were found for the other three models (ACvs AA: OR=0.91, 95% CI=0.81~1.02; the dominant model: OR=0.90, 95% CI=0.80~1.00; the recessive model:OR=0.84, 95% CI =0.72~1.00). In the subgroup analysis by ethnicity, we detected significant associationsbetween the CYP1A2 rs762551 polymorphism and bladder cancer susceptibility for GA vs GG (OR = 0.78,95% CI =0.64~0.96) and for the recessive model (OR=0.80, 95% CI=0.66~0.96) in Caucasians, but not forAsians. Conclusions: The results from the meta-analysis suggested that the CYP1A2 rs762551 polymorphism isa protective factor for bladder cancer, especially in Caucasians.     

The MDM2 SNP309T>G Polymorphism Increases Bladder Cancer Risk among Caucasians: a Meta-analysis

Published studies have evaluated associations between the MDM2 SNP309T>G polymorphism and bladder cancer susceptibility. However, these generated inconsistent results. The aim of the present investigation was to quantify the strength of association between MDM2 SNP309T>G polymorphism and bladder cancer risk by conducting a meta-analysis. We searched PubMed and Embase for related studies that had been published in English before April 1, 2014 and associations were assessed by summarizing the odds ratios (ORs) with thecorresponding 95% confidence intervals (CIs). Five case-control studies with a total of 972 cases and 1,012 controls were finally identified to be eligible for the meta-analysis. Overall, the results indicated that there was no significant association between the MDM2 SNP309T>G polymorphism and bladder cancer risk (for the allele model G vs. T: OR=1.08, 95% CI 0.85-1.36, p=0.54; for the co-dominant model GG vs. TT: OR=1.20, 95% CI 0.74-1.93, p=0.46; for the dominant model GG+GT vs. TT: OR=0.98, 95% CI 0.80-1.20, p=0.83; for the recessive model GG vs. GT+TT: OR=1.20, 95% CI 0.83-1.74, p=0.33). However, on subgroup analysis by ethnicity, significant associations were found in Caucasians in three models (for the allele model G vs. T: OR=1.41, 95% CI 1.10-1.81, p=0.006; for the co-dominant model GG vs. TT: OR=2.16, 95% CI 1.28-3.63, p=0.004; for therecessive model GG vs. GT+TT: OR=2.06, 95% CI 1.31-3.22, p=0.002). In summary, the present meta-analysis provides evidence that the genotype for the MDM2 SNP309T>G polymorphism may be associated with genetic susceptibility to bladder cancer among Caucasians.     

CYP1A1、GSTM1基因多态性与肺癌易感性的研究

目的:探讨CYP1A1、GSTM1基因多态性与肺癌易感性之间的相关性。方法:利用RFLP-PCR(限制性片段长度多态性-聚合酶链反应)方法检测65例原发性肺癌和60例非肿瘤患者CYP1A1、GSTM1基因,再用NcoI及HinfI两种内切酶识别CYP1A1等位基因亚型。结果:1)肺癌组与对照组CYP1A1等位基因型Ile/Ile、Ile/Val、Val/Val的频率总体分布无显著性差异;但肺癌组CYP1A1(Val/Val)基因型频率(18.5%)明显高于对照组(8.3%),两组差异有显著性(P<0.05)。2)肺癌组GSTM1(-)基因型的频率(63.1%)明显高于对照组(45.0%),P<0.05。3)两种等位基因联合分析发现,与携带CYP1A1(Ile/Ile)/GSTM1(+)基因型的个体相比:CYP1A1(Ile/Ile)/GSTM1(-)以及CYP1A1(Ile/Val+Val/Val)/GSTM1(+)基因型个体患肺癌的风险度较高,OR分别为3.82(95.0%CI,1.27～11.45)和3.5(95.0%CI,1.18～10.41);而CYP1A1(Val/Val)/GSTM1(-)基因型个体患肺癌的风险度最高,OR为10.5(95.0%CI,1.70～64.73)。4)进一步分层分析发现,CYP1A1(Ile/Val+Val/Val)等位基因型主要增加鳞癌的危险性;而GSTM1基因型组织类型无明显的相关性。5)在分析吸烟对肺癌易感性的影响时发现,CYP1A1(Ile/Val+Val/Val)及GSTM1(-)等位基因型与吸烟有协同作用,并与至发病时的累积吸烟量有关。结论:CYP1A1(Val/Val     

Four Polymorphisms in the Cytochrome P450 1A2 (CYP1A2) Gene and Lung Cancer Risk: a Meta-analysis

Background: Previous published data on the association between CYP1A2 rs762551, rs2069514, rs2069526,and rs2470890 polymorphisms and lung cancer risk have not allowed a definite conclusion. The present metaanalysisof the literature was performed to derive a more precise estimation of the relationship. Materials andMethods: 8 publications covering 23 studies were selected for this meta-analysis, including 1,665 cases and 2,383controls for CYP1A2 rs762551 (from 8 studies), 1,456 cases and 1,792 controls for CYP1A2 rs2069514 (from 7studies), 657 cases and 984 controls for CYP1A2 rs2069526 (from 5 studies) and 691 cases and 968 controls forCYP1A2 rs2470890 (from 3 studies). Results: When all the eligible studies were pooled into the meta-analysisfor the CYP1A2 rs762551 polymorphism, significantly increased lung cancer risk was observed in the dominantmodel (OR=1.21, 95 % CI=1.00-1.46). In the subgroup analysis by ethnicity, significantly increased risk of lungcancer was observed in Caucasians (dominant model: OR=1.29, 95%CI=1.11-1.51; recessive model: OR=1.33,95%CI=1.01-1.75; additive model: OR=1.49, 95%CI=1.12-1.98). There was no evidence of significant associationbetween lung cancer risk and CYP1A2 rs2069514, s2470890, and rs2069526 polymorphisms. Conclusions: Insummary, this meta-analysis indicates that the CYP1A2 rs762551 polymorphism is linked to an increased lungcancer risk in Caucasians. Moreover, our work also points out the importance of new studies for rs2069514associations in lung cancer, where at least some of the covariates responsible for heterogeneity could be controlled,to obtain a more conclusive understanding about the function of the rs2069514 polymorphism in lung cancerdevelopment.     

谷胱甘肽硫转移酶A1(GSTA1)基因多态性与前列腺癌和膀胱癌易感性的Meta分析

目的 探讨谷胱甘肽硫转移酶A1(GSTA1)基因多态性与前列腺癌及膀胱癌易感性的关系.方法 通过检索PubMed等数据库,获取GSTA1基因多态性与前列腺癌或膀胱癌的文献9篇,对1989例病例和2246例对照进行meta分析,以比值比(OR)和95%可信区间(CI)作为效应指标.结果 各遗传模型的Meta分析显示:GSTA1基因多态性与前列腺癌易感性的相关性无统计学意义[(AA vs BB:OR=0.92,95%CI:0.68~1.23,P=0.56);(AB vs BB:OR=1.02,95%CI:0.86~1.21,P=0.83);(AA/AB vs BB OR=1.01,95%CI:0.86~1.17,P=0.93);(AA vs AB/BB:OR=0.91,95%CI:0.69~1.20,P=0.51)].各遗传模型的Meta分析显示:GSTA1基因多态性与膀胱癌易感性的相关性无统计学意义[(AA vs BB:OR=0.97,95%CI:0.71~1.33,P=0.85);(AB vs BB:OR=1.11,95%CI:0.93~1.31,P=0.25);(AA/AB vs BB OR=1.07,95%CI:0.92~1.25,P=0.37);(AA vs AB/BB:OR=0.87,95%CI:0.64~1.18,P=0.37)].结论 单独的GSTA1基因多态性不是前列腺癌和膀胱癌的易感因素.     

N-Acetyltransferase 2 Gene Polymorphisms are Associated with Susceptibility to Cancer: a Meta-analysis

N-acetyltransferase 2 (NAT2) is a polymorphic enzyme that plays an important role in the metabolism ofvarious potential carcinogens. In recent years, a number of studies have been carried out to investigate therelationship between the rs1799930 and rs1799931 polymorphism in NAT2 and cancer risk in multiple populationsfor different types of cancer. However, the results were not consistent. Therefore, we performed a meta-analysisto further explore the relationship between NAT2 polymorphism and the risk of cancer. A total of 21 studiesinvolving 15, 450 subjects for rs1799930 and 13, 011 subjects for rs1799931 were included in this meta-analysis.Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess strength of associations. Wealso evaluated the publication bias and performed a sensitivity analysis. Overall, our results showed an apparentsignificant association between the NAT2 rs1799930 polymorphism and cancer susceptibility in Asians (GAvs. GG: OR=1.22, 95% CI=1.03-1.45; dominant model: OR=1.22, 95% CI=1.03-1.43) and population-basedcontrols (GA vs. GG: OR=1.10, 95% CI=1.01-1.19; dominant model: OR=1.09, 95% CI=1.01-1.18). In contrast,a significant association was observed between the NAT2 rs1799931 G>A polymorphism and decreased cancersusceptibility in overall meta-analysis (AA vs. GG: OR=0.55, 95% CI=0.33-0.93; GA vs. GG: OR=1.00, 95%CI=0.88-1.14; dominant model: OR=0.97, 95% CI=0.86-1.10; recessive model: OR=0.56, 95% CI=0.34-0.94)and the Asian group (AA vs. GG: OR=0.50, 95% CI=0.26-0.94; recessive model, OR=0.50, 95% CI=0.27-0.94).We found that the NAT2 rs1799930 may be a risk factor, while the NAT2 rs1799931 polymorphism is associatedwith a decreased risk of cancer and is likely a protective factor against cancer development.     

Association Between GSTM1 Polymorphism and Nasopharyngeal Cancer Susceptibility: a Meta-analysis

Background/Aims: Glutathione S-transferase M1 (GSTM1) is a multifunctional enzyme that plays a criticalrole in the detoxification of varieties of carcinogenic metabolites. Many studies have been conducted to investigatethe association between GSTM1 polymorphism and nasopharyngeal cancer (NPC) risk, but the findings amongthose studies are inconsistent. To assess this relationship more precisely, we performed a meta-analysis of allavailable studies on the subject. Methods: Case-control studies were identified by searching Pubmed, Embase,ISI Web of Science, and Wanfang databases through September 6, 2012. We used the pooled odds ratio (OR)with its corresponding 95% confidence interval (95%CI) to evaluate the association of GSTM1 polymorphismwith NPC susceptibility. Subgroup analyses by pathological types, sex and smoking status were performed tofurther identify the association. Results: Overall, 11 published studies with 1,513 cases and 2,802 controls werefinally included into this meta-analysis according to the inclusion criteria. Meta-analysis of total studies showedthat the null genotype of GSTM1 was significantly associated with increased risk of NPC, when comparing withthe non-null genotype (OR=1.51, 95%CI=1.33-1.72, POR<0.001). The association was still statistically significantin subgroup analysis of patients with nasopharyngeal squamous cell carcinoma (OR=1.73, 95%CI=1.24-2.42,POR=0.001). Males with the null genotype of GSTM1 were more likely to subject to NPC than females. Inaddition, the association between the null genotype of GSTM1 and NPC risk was strongest in individuals withexposure to smoking. Sensitivity analysis by sequential omission of any individual studies one at a time furtherdemonstrated the significant association. Conclusions: The findings suggest that the null genotype of GSTM1 isa risk factor for NPC, and there is a gene- smoking interaction in this association