MTHFR基因A1298C多态性与肠癌遗传易感相关性研究

目的：探讨亚甲基四氢还原酶基因（MTHFR）第7外显子区单核苷酸多态（single nucleotide polymo-rphism,SNP）位点A1298C（rs1801131）与中国南方人群肠癌发生的相关性。方法：应用基质辅助激光解吸电离飞行时间（MALDI-TOF）质谱检测224例肠癌和224例对照MTHFR基因多态位点rs1801131的基因型。结果：MTHFR rs1801131多态位点AA、AC、CC三种基因型在肠癌的频率为63.4%、32.6%和4.0%,与对照组（68.8%,29.9%和3%）相比差异不显著（P=0.12）;但男性人群中病例组和正常组的基因型差异接近显著（P=0.05）,携带CC基因型男性个体的肠癌发病风险显著增加（OR=8.38,95%CI：1.01-69.64）;相对于直肠癌,结肠癌与正常对照的基因型频率差别更大,P值分别为0.84和0.08;且男性结肠癌患者基因型分布和对照差异显著（P=0.01）。结论：MTHFR基因第7外显子区rs1801131位点的单核苷酸多态性可能与中国南方人群结肠癌的遗传易感性相关,而与直肠癌无关,特别是在男性人群中rs1801131 CC和CA基因型可能增加个体患结肠癌的风险。     

亚甲基四氢叶酸还原酶基因多态性与结直肠癌易感性的关系

目的：研究亚甲基四氢叶酸还原酶（methylenetetrahydrofolate reductase,MTHFR）基因C677T、A1298C多态性与结直肠癌易感性的关系.方法：在江苏省进行了一个病例-对照研究（结直肠癌患者315例,人群对照371例）,调查研究对象的生活习惯,抽取静脉血,提取白细胞DNA,采用PCR-RFLP检测研究对象的MTHFR C677T、A1298C基因型.结果：1）男女合计的结直肠癌组、结肠癌组和直肠癌组与对照组之间的MTHFR C677T、A1298C基因型分布频度和等位基因频度差异无统计学意义,MTHFR C677T、A1298C基因多态与结直肠癌、结肠癌和直肠癌的易感性无显著相关.2）在男性中,结肠癌组MTHFR C677T T/T基因型的频度为24.6%,明显高于对照组的14.8%,但差异无统计学意义,X2=3.42,P=0.064.与C677T C等位基因携带者相比,T/T基因型者发生结肠癌的危险性显著升高,其性别、年龄、居住地区及吸烟、饮酒和饮茶习惯调整后的OR为2.15（95%CI：1.07～4.33）.与同时携带MTHFR C677T C等位基因和A1298C A/A基因型者相比,男性的MTHFR C677T T/T和A1298C A/A基因型携带者发生结肠癌的危险性显著升高,其调整OR为2.64（95%CI：1.20～5.81）,而他们发生直肠癌的危险性则明显降低,（调整OR=0.47,95%CI：0.22～1.03）.结论：MTHFR C677T基因多态可以影响男性结、直肠癌的易感性,MTHFR A1298C多态与C677T多态在对男性结、直肠癌易感性的影响中有协同作用.     

亚甲基四氢叶酸还原酶基因单核苷酸多态性与儿童急性淋巴细胞白血病的相关性

 【摘要】　目的　探讨亚甲基四氢叶酸还原酶基因（MTHFR）单核甘酸多态性与儿童急性淋巴细胞白血病（ALL）发病风险的关系。方法　分别收集45例ALL患儿（ALL组）及45名健康儿童（对照组）外周血各2 ml,提取基因组DNA,应用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）法,检测MTHFR C677T和A1298C基因型,比较不同基因型对儿童ALL发病风险的影响。采用Logistic回归模型计算比值比（OR）和95 %可信区间（95 % CI）。结果　对照组MTHFR 677CC、CT和TT基因型基因分布频率分别为31.1 %（14／45）、51.1 %（23／45）和17.7 %（8／45）,ALL组3种基因型分布频率分别为51.1 %（23／45）、40.0 %（18／45）和8.9 %（4／45）,两者比较差异有统计学意义（χ2＝7.48,P＝0.04）;MTHFR 677 T等位基因在ALL组中的检出率为48.8 %（22／45）,在对照组中的检出率为69.9 %（31／45）;T等位基因携带者发生ALL的风险是CC基因型的0.4倍（95 % CI 0.21～0.83）。对照组MTHFR 1298AA、AC和CC基因型基因分布频率分别为57.8 %、40.0 %和2.2 %,ALL组中3种基因型分布频率分别为18.8 %、44.4 %和6.8 %,两者比较差异无统计学意义（χ2＝11.23,P＝0.23）;MTHFR 1298 C等位基因ALL组中的检出率为42.2 %（19／45）,对照组中的检出率为51.1 %（23／45）;C等位基因的存在并不会提高儿童ALL发生的风险（OR＝1.3,95 % CI 0.21～0.83）。结论　MTHFR 677 T等位基因的存在会显著降低儿童发生ALL的风险,而MTHFR 1298各基因型与儿童ALL的发生均无明显相关性。     

MTHFR基因A1298C多态性与肠癌遗传易感相关性研究

目的:探讨亚甲基四氢还原酶基因(MTHFR)第7外显子区单核苷酸多态(single nucleotide polymorphism,SNP)位点A1298C(rs1801131)与中国南方人群肠癌发生的相关性.方法:应用基质辅助激光解吸电离飞行时间(MALDI-TOF)质谱检测224例肠癌和224例对照MTHFR基因多态位点rs1801131的基因型.结果:MTHFR rs1801131多态位点AA、AC、CC三种基因型在肠癌的频率为63.4%、32.6%和4.0%,与对照组(68.8%,29.9%和3%)相比差异不显著(P=0.12);但男性人群中病例组和正常组的基因型差异接近显著(P=0.05),携带CC基因型男性个体的肠癌发病风险显著增加(OR=8.38,95%CI:1.01-69.64);相对于直肠癌,结肠癌与正常对照的基因型频率差别更大,P值分别为0.84和0.08;且男性结肠癌患者基因型分布和对照差异显著(P=0.01).结论:MTHFR基因第7外显子区rs1801131位点的单核苷酸多态性可能与中国南方人群结肠癌的遗传易感性相关,而与直肠癌无关,特别是在男性人群中rs1801131 CC和CA基因型可能增加个体患结肠癌的风险.     

亚甲基四氢叶酸还原酶基因多态性与结直肠癌易感性的关系

目的:研究亚甲基四氢叶酸还原酶(methylenetetrahydrofolate reductase,MTHFR)基因C677T、A1298C多态性与结直肠癌易感性的关系。方法:在江苏省进行了一个病例-对照研究(结直肠癌患者315例,人群对照371例),调查研究对象的生活习惯,抽取静脉血,提取白细胞DNA,采用PCR-RFLP检测研究对象的MTHFR C677T、A1298C基因型。结果:1)男女合计的结直肠癌组、结肠癌组和直肠癌组与对照组之间的MTHFR C677T、A1298C基因型分布频度和等位基因频度差异无统计学意义,MTHFR C677T、A1298C基因多态与结直肠癌、结肠癌和直肠癌的易感性无显著相关。2)在男性中,结肠癌组MTHFR C677T T/T基因型的频度为24.6%,明显高于对照组的14.8%,但差异无统计学意义,χ2=3.42,P=0.064。与C677T C等位基因携带者相比,T/T基因型者发生结肠癌的危险性显著升高,其性别、年龄、居住地区及吸烟、饮酒和饮茶习惯调整后的OR为2.15(95%CI:1.07~4.33)。与同时携带MTHFR C677T C等位基因和A1298C A/A基因型者相比,男性的MTHFR C677T T/T和A1298C A/A基因型携带者发生结肠癌的危险性显著升高,其调整OR为2.64(95%CI:1.20~5.81),而他们发生直肠癌的危险性则明显降低,(调整OR=0.47,95%CI:0.22~1.03)。结论:MTHFR C677T基因多态可以影响男性结、直肠癌的易感性,MTHFR A1298C多态与C677T多态在对男性结、直肠癌易感性的影响中有协同作用。     

p73及p53基因多态性与甘肃武威人群胃癌风险相关性研究

[目的]评价p73基因G4C14-to-A4T14双核苷酸多态性（p73 G4A DNP）和p53基因第72密码子单核苷酸多态性（p53 Arg72Pro SNP）与甘肃武威市人群胃癌高发风险及胃癌不同病理亚型的相关性。[方法]p73G4ADNP的基因分型采用两双相对引物多聚酶链式反应法,p53 Arg72Pro SNP基因分型采用PCR-RFLP法。[结果]共检查胃癌病例385例以及健康对照412人。胃癌组中弥漫型胃癌305例（79.22%）,肠型胃癌80例（20.78%）。对照组p73AT/AT、AT/GC及GC/GC基因型的频率分别为28.15%、47.09%和24.76%;胃癌组分别为21.98%、45.04%和32.98%;以AT/AT作为指示物,胃癌组和弥漫型胃癌的GC/GC纯合子基因型频率均高于对照组,优势比（OR）分别为1.71（95%CI,1.16～2.51）和1.87（1.24～2.81）。对照组p53基因Pro/Pro、Pro/Arg以及Arg/Arg基因型的频率分别为27.18%、50.49%及22.33%;胃癌组则分别为21.82%、45.45%和32.73%;以Pro/Pro为指示物,胃癌组和弥漫型胃癌Arg/Arg基因型频率显著高于对照组,OR分别为1.83（95%CI,1.24～2.70）和2.25（95%CI,1.47～3.43）。[结论]携带p73 G4A GC/GC基因型或p53 Arg/Arg基因型可能会增加胃癌,尤其是弥漫性胃癌的发病风险。     

p53基因codon 72多态性与乳腺癌术后放化疗疗效相关性分析

目的:分析p53基因codon 72多态性与乳腺癌患者术后放化疗的预后相关性。方法:选取北京大学肿瘤医院乳腺癌患者术后接受放化疗427 例,采用聚合酶链反应- 限制性片段长度多态性（PCR-RFLP ）方法分析其p53基因codon 72多态性,比较不同基因型患者间复发及生存的差异。结果:全部患者基因型分布为Pro/Pro 型18.3%（78/427）、Pro/Arg型44.0%（188/427）、Arg/Arg型37.7%（161/427）。3 种基因型间无局部复发生存（LRFS）、无局部区域复发生存（LRRFS ）、无远处转移生存（DDFS）及总生存（OS）均无显著性差异（均P>0.05）。 427 例患者中雌激素受体（ER）阳性为303 例,其中Arg/Arg基因型患者OS明显优于Pro/Pro 基因型患者（χ2=6.330,P=0.042）。 在多因素分析中p53基因codon 72多态性是ER阳性患者LRFS、LRRFS 、DDFS及OS的独立预后因素,Pro/Pro 基因型的患者较Arg/Arg基因型的局部复发风险增加5.9 倍（HR= 5.9,95%CI 1.1～31.1,P=0.036）,局部区域复发风险增加3.1 倍（HR= 3.1,95%CI 1.1～9.1,P=0.039）,远处转移风险增加2.8 倍（HR= 2.8,95%CI 1.3～6.0,P=0.010）,死亡风险增加4 倍（HR= 4.0,95%CI 1.3～12.0,P=0.013）。 结论:在ER阳性的乳腺癌术后接受放化疗患者中,Pro/Pro 基因型的局部及局部区域复发风险、远处转移风险、死亡风险均高于Arg/Arg基因型。      

中国人群XRCC1 Arg399Gln 基因多态性与结直肠癌易感性关系的Meta分析

摘 要：［目的］探讨X线修复交叉互补基因1（X-ray repair cross complementing group 1,XRCC1）Arg399Gln基因多态性与中国人群结直肠癌易感性的关系。［方法］在PubMed、MEDLINE、EMBASE、中国知网、维普、中国生物医学文献及万方数据库中检索建库至2016年4月10日之间发表的有关XRCC1 Arg399Gln基因多态性与中国人群结直肠癌易感性关系的相关文献。按照纳入和排除标准独立选择文献、提取资料,采用Stata 12.0软件进行Meta分析,计算合并比值比（OR）及其95%可信区间（95%CI）,并进行敏感性分析和发表偏倚的估计。［结果］ 共纳入11项研究,包括3502例患者和4828例对照者。Meta分析结果显示,在Gln/Gln vs Arg/Gln遗传模型中,XRCC1 Arg399Gln基因多态性与中国人群结直肠癌发生风险有显著相关性,与基因型Arg/Gln相比,基因型Gln/Gln增加了中国人群罹患结直肠癌的风险（OR=1.23,95%CI：1.04~1.46,P=0.016）。其余遗传模型中两者间无明显相关性。［结论］ 在Gln/Gln vs Arg/Gln遗传模型中,XRCC1 Arg399Gln基因多态性与中国人群结直肠癌易感性相关,基因型Gln/Gln增加中国人群罹患结直肠癌的风险。     

NQO1基因C609T多态性和环境因素与乳腺癌遗传易感性的关系

目的探讨醌氧化还原酶1(quinone oxido-reductase 1,NQO1)基因C609T多态性和环境因素与乳腺癌遗传易感性的关系。方法采用以医院为基础的病例对照研究收集桂林医学院附属医院2012-10-15-2014-02-15共248例女性乳腺癌患者和该院2013-03-01-2013-12-30共284名女性健康体检者的人口学和环境暴露资料等,并采用TaqMan MGB荧光定量聚合酶链反应技术和多因素非条件Logistic回归模型分析NQO1基因C609T在两组中分布频率的差异,以及与环境因素的交互作用。结果病例组NQO1基因位点CC、CT和TT各基因型频率分别为27.42%、49.60%和22.98%,对照组中基因型频率分别为34.51%、50.35%和15.14%,差异有统计学意义,χ2=6.48,P=0.039。多因素Logistic回归分析表明,与CC基因型相比,CT或TT基因型的个体罹患乳腺癌的风险OR值分别为1.33和2.92。病例组等位基因T频率(47.78%)较对照组(40.32%)增高(χ2=6.00,P=0.014),携带T等位基因者患乳腺癌的危险性是C等位基因携带者的1.36倍。交互作用分析表明,NQO1基因C609T多态性与经常熬夜、被动吸烟、精神创伤、睡觉佩戴胸罩、性格和体育锻炼等之间均存在交互作用(P<0.05),其OR值分别为2.45、3.96、2.40、1.98、0.33和0.52。结论NQO1基因C609T多态性可能为乳腺癌发病的遗传易感因素,且与环境因素具有协同致癌作用。     

DNA修复基因XPD XPC XRCC4基因多态性与结直肠癌易感性的关联性研究

  目的  探讨DNA修复基因XPD rs13181（codon751A/C,Lys751Gln）、rs238406（codon156C/A,Arg156Arg）、XPC rs2279017（i11C/A）和XRCC4 rs3734091（codon247T/C,Ala247Ser）的单核苷酸多态性与结直肠癌易感性的关系。  方法  采用TaqMan技术对2013年4月至2016年1月北京肿瘤医院收治的338例结直肠癌患者（病例组）和315例健康者（对照组）进行多态位点基因型的检测。  结果  XPD rs13181基因型GT和等位基因G增加个体结直肠癌的发病风险（GT>TT,adjusted OR=1.69,95%CI:1.15~2.47,P=0.007;G>T,adjusted OR=1.77,95%CI:1.19~2.64,P=0.005）;XRCC4 rs3734091基因型GT和等位基因T增加个体结直肠癌的易感性（GT>GG,adjusted OR=9.02,95%CI:5.61~14.50,P＜0.001;T>G,adjusted OR=4.06,95%CI:2.49~6.61,P＜0.001）;XPD rs13181和rs238406的单倍体型GT显著降低结直肠癌的发病风险（adjusted OR=0.39,95%CI:0.18~0.85,P=0.018）。XPCrs2279017等位基因G和XRCC4 rs3734091等位基因T的联合效应（adjusted OR=28.43,95%CI:6.85~117.95,P＜0.001）以及XPD rs13181等位基因G和XRCC4 rs3734091等位基因T的联合效应（adjusted OR=10.24,95%CI:4.69~22.35,P＜0.001）显著增加个体结直肠癌的易感性。  结论  XPD rs13181和XRCC4 rs3734091位点的多态性与结直肠癌的易感性相关。      

MTHFR polymorphisms and pancreatic cancer risk: lack of evidence from a meta-analysis

Objective: Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms have been reported tobe associated with pancreatic cancer, but the published studies had yielded inconsistent results.We thereforeperformed the present meta-analysis. Methods: A search of Google scholar, PubMed, Cochrane Library andCNKI databases before April 2012 was conducted to summarize associations of MTHFR polymorphisms withpancreatic cancer risk. Assessment was with odds ratios (ORs) and 95% confidence intervals (CIs). Publicationbias were also calculated. Results: Four relative studies on MTHFR gene polymorphisms (C667T and A1298C)were involved in this meta-analysis. Overall, C667T(TT vs. CC : OR = 1.61, 95%CI = 0.78 - 3.34; TT vs. CT :OR = 1.41, 95%CI = 0.88-2.25; dominant model: OR = 0.68, 95%CI = 0.40-1.17; recessive model: OR = 0.82,95%CI = 0.52-1.30) and A1298C(CC vs. AA:OR=1.01, 95%CI=0.47-2.17; CC vs. AC: OR=0.99,95%CI=0.46-2.14;dominant model: OR=1.01, 95%CI = 0.47-2.20; recessive model: OR = 1.01, 95%CI = 0.80-1.26) did not increasepancreatic cancer risk. Conclusion: This meta-analysis indicated that MTHFR polymorphisms (C667T andA1298C) were not associated with pancreatic cancer risk.     

No Association Between MTHFR A1298C Gene Polymorphism and Head and Neck Cancer Risk: A Meta-analysis Based on 9,952 Subjects

Objective: Findings for associations between the methylenetetrahydrofolate reductase (MTHFR) A1298C genepolymorphism and head and neck cancer risk have been conflicting. We therefore performed a meta-analysisto derive a more precise relationship. Methods: Ten published case-control studies were collected and oddsratios (ORs) with 95% confidence intervals (CIs) were used to assess the association between MTHFR A1298Cpolymorphism and head and neck cancer risk. Sensitivity analysis and publication bias assessment also wereperformed to guarantee the statistical power. Results: Overall, no significant association between MTHFR A1298Cpolymorphism and head and neck cancer risk was found in this meta-analysis (C vs. A: OR=1.04, 95%CI=0.87-1.25, P=0.668, Pheterogeneity<0.001; CC vs. AA: OR=1.07, 95%CI=0.70-1.65, P=0.748, Pheterogeneity<0.001; ACvs. AA: OR=1.06, 95%CI=0.88-1.27, P=0.565, Pheterogeneity<0.001; CC+AC vs. AA: OR=1.06, 95%CI=0.86-1.30,P=0.571, Pheterogeneity<0.001; CC vs. AA+AC: OR=1.02, 95%CI=0.69-1.52, P=0.910, Pheterogeneity<0.001). Similarresults were also been found in succeeding analysis of HWE and stratified analysis of ethnicity. Conclusions: Inconclusion, our meta-analysis demonstrates that MTHFR A1298C polymorphism may not be a risk factor fordeveloping head and neck cancer.     

MTHFR Gene Polymorphisms are Not Involved in Pancreatic Cancer Risk: A Meta-analysis

Purpose: Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms have been reported to beassociated with pancreatic cancer, but the published studies have yielded inconsistent results. This study assessedthe relationship between MTHFR gene polymorphisms and the risk for pancreatic cancer using a meta-analysisapproach. Methods:A search of Google scholar, PubMed, Cochrane Library and CNKI databases before April 2012was performed, and then associations of the MTHFR polymorphisms with pancreatic cancer risk were summarized.The association was assessed by odds ratios (ORs) with 95% confidence intervals (CIs). Publication bias was alsocalculated. Results: Four relative studies on MTHFR gene polymorphisms (C667T and A1298C) were included inthis meta-analysis. Overall, C667T (TT vs. CC:OR=1.61,95%CI=0.78-3.34; TT vs. CT: OR=1.41,95%CI=0.88-2.25;Dominant model:OR=0.68,95%CI=0.40-1.17; Recessive model: OR=0.82,95%CI=0.52-1.30) and A1298C (CCvs. AA:OR=1.01,95%CI=0.47-2.17; CC vs. AC: OR=0.99,95%CI=0.46-2.14; Dominant model:OR=1.01,95%CI=0.47-2.20; Recessive model: OR=1.01,95%CI=0.80-1.26) did not increase pancreatic cancer risk.Conclusions: This meta-analysis indicated that MTHFR polymorphisms (C667T and A1298C) are not associatedwith pancreatic cancer risk.     

Genetic polymorphisms of methylenetetrahydrofolate reductase and susceptibility to colorectal cancer

Objectives: To study the relation between genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR) C677T or A1298C and the susceptibility of colorectal cancer. Methods: We conducted a case-control study with 315 cases of colorectal cancer and 371 population-based controls in Jiangsu province, China. The epidemiological data were collected, and DNA of peripheral blood leukocytes was obtained from all of the subjects. MTHFR C677T and A1298C genotypes were detected by the PCR-RFLP method. Results: (1) When men and women were assessed together, the frequencies of the MTHFR C677T and A1298 genotypes or their alleles were not significantly different between controls and colon cancer or rectal cancer cases. No significant relation was observed between MTHFR C677T or A1298C polymorphisms and colon or rectal cancer susceptibility. (2) Among males, individuals who had MTHFR C677T T/T genotype were at a significantly higher risk of developing colon cancer (age-, residence-, smoking-, alcohol drinking-, tea consumption-adjusted OR=2.15, 95%CI: 1.07-4.33) compared with those who had C677T C allele. Individuals who had C677T T/T and A1298C A/A genotypes were at an increased risk of developing colon cancer (adjusted OR=2.64, 95%CI: 1.20-5.81) compared with those with C677T C allele and A1298C A/A genotypes among males. On the contrary, individuals who had C677T T/T and A1298C A/A genotypes were at an decreased risk of developing rectal cancer (adjusted OR=0.47, 95%CI: 0.22-1.03). Conclusions: These results in the present study suggested that polymorphisms of the MTHFR C677T could influence susceptibility to colon or rectal cancer and that there was a coordinated effect between MTHFR A1298C A/A and C677T T/T genotypes among males.     

Allele and Genotype Frequencies of the Polymorphic Methylenetetrahydrofolate Reductase and Colorectal Cancer among Jordanian Population

Background: Methylenetetrahydrofolate reductase (MTHFR) is involved in DNA synthesis and repair. We hereaimed to investigate two common polymorphisms, C677T and A1298C, with genotype and haplotype frequenciesin colorectal cancer (CRC) cases among Jordanian. Materials and Methods: 131 CRC cases were studied forMTHFR C677T and A1298C polymorphisms, compared to 117 controls taken from the general population,employing the PCR-RFLP technique. Results: We found the frequency of the three different genotypes of MTHFRC677T among Jordanians to be CC: 61.7%, CT: 35.2%, and TT 3.1% among CRC cases and 50.9%, 38.8% and10.3% among controls. Carriers of the TT genotype were less likely to have CRC (OR=0.25; 95%CI: 0.076-0.811;p=0.021) as compared to those with the CC genotype. Genotype analysis of MTHFR A12987C revealed AA:38.9%, AC: 45%, and CC 16% among CRC cases and 37.4%, 50.4% and 12.2% among controls. There wasno significant association between genetic polymorphism at this site and CRC. Haplotype analysis of MTHFRpolymorphism at the two loci showed differential distribution of the TA haplotype (677T-1298A) between casesand controls. The TA haplotype was associated with a decreased risk for colorectal cancer (OR=0.6; 95% CI:0.4-0.9, p=0.03). Conclusions: The genetic polymorphism of MTHFR at 677 and the TA haplotype may modulatethe risk for CRC development among the Jordanian population. Our findings may reflect an importance of genesinvolved in folate metabolism in cancer risk.     

NAD(P)H: Quinone Oxidoreductase 1 (NQO1) C609T Gene Polymorphism Association with Digestive Tract Cancer: A Meta-analysis

NAD(P)H: quinone oxidoreductase 1 (NQO1) C609T gene polymorphisms have been reported to influence therisk for digestive tract cancer (DTC) in many studies; however, the results remain controversial and ambiguous.We therefore carried out a meta-analysis of published case-control studies to derive a more precise estimationof any associations. Electronic searches were conducted on links between this variant and DTC in severaldatabases through April 2012. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated toestimate the strength of associations in fixed or random effect models. Heterogeneity and publication bias werealso assessed. A total of 21 case-control studies were identified, including 6,198 cases and 7,583 controls. Overall,there was a statistically significant association between the NQO1 C609T polymorphism and DTC risk (TT vs.CC: OR=1.224, 95%CI=1.055-1.421; TT/CT vs. CC: OR=1.195, 95%CI=1.073-1.330; TT vs. CT/CC: OR=1.183,95%CI=1.029-1.359; T vs. C: OR=1.180, 95%CI=1.080-1.290). When stratified for tumor location, the resultsbased on all studies showed the variant allele 609T might have a significantly increased risk of upper digest tractcancer (UGIC), but not colorectal cancer. In the subgroup analysis by ethnicity, we observed a significantly riskfor DTC in Caucasians. For esophageal and gastric cancer, a significantly risk was found in both populations,and for colorectal, a weak risk was observed in Caucasians, but not Asians. This meta-analysis suggested thatthe NQO1 C609T polymorphism may increase the risk of DTC, especially in the upper gastric tract.     

鼠双微体同源基因2遗传多态与结直肠癌患病风险的相关性

目的 探讨p53 72 Arg→Pro和鼠双微体同源基因2(MDM2) 309 T→G多态与结直肠癌(CRC)发生发展的关系.方法 采用病例-对照关联研究方法,分析1000例CRC和1300例正常对照中p53 72 Arg→Pro和MDM2 309 T→G的基因型.以多因素Logistic回归模型计算各基因型的比值比(OR)及其95%可信区间(CI).结果 携带MDM2 309 GG或TG基因型者患CRC的风险比TT基因型者显著增高,OR分别为2.06(95%CI为1.62～2.62)和1.31(95%CI为1.06～1.62).p53 72 Arg→Pro多态与CRC风险不相关.两个基因多态联合分析表明,既携带MDM2 309 GG,又携带p53 72 Pro/Pro基因型者,患CRC的OR显著高于携带MDM2 309 TT和p53 72 Pro/Pro基因型者[2.75(95%CI为1.60～4.70)比1.09(95%CI为0.63～1.88);χ2=9.83,P=0.002].结论 MDM2基因的遗传多态可能是CRC的遗传易感性因素.     

Allele and Genotype Frequencies of the Polymorphic Methylenetetrahydrofolate Reductase and Lung Cancer in ther Jordanian Population: a Case Control Study

Background: Methylenetetrahydrofolate reductase (MTHFR) is involved in amino acid synthesis and DNAfunction. Two common polymorphisms are reported, C677T and A1298C, that are implicated in a number ofhuman diseases, including cancer. Objective: The association between MTHFR C677T and A1298C genotype andhaplotype frequencies in risk for lung cancer (LC) was investigated in the Jordanian population. Materials andMethods: A total of 98 LC cases were studied for MTHFR C677T and A1298C polymorphisms, compared to 89controls taken from the general population, employing the PCR-RFLP technique. Results: The frequency of thegenotypes of MTHFR C677T among Jordanians was: CC, 59.6%, CT, 33%; and TT, 7.4% among LC cases and49.4%, 40.2% and 10.3% among controls. No significant association was detected between genetic polymorphismat this site and LC. At MTHFR A12987C, the genotype distribution was AA, 29.5%; AC, 45.3%, and CC 25.3%among LC cases and 36.8%, 50.6% and 12.6% among controls. Carriers of the CC genotype were more likelyto have LC (OR=2.5; 95%CI: 1.04-6; p=0.039) as compared to AA carriers. Smokers and males with the CCgenotype were 9.9 and 6.7 times more likely to have LC, respectively (ORsmokers=9.9; 95%CI: 1.2-84.5, p=0.018;ORmen=6.6; 95%CI: 1.7-26.2, p=0.005). Haplotype analysis of MTHFR polymorphism at the two loci showeddifferential distribution of the CC haplotype (677C-1298C) between cases and controls. The CC haplotypewas associated with an increased risk for lung cancer (OR=1.6; 95% CI: 1.03-2.4, p=0.037). Conclusions: Thegenetic polymorphism of MTHFR at 1298 and the CC haplotype (risk is apparently lower with the C allele atposition 677) may modulate the risk for LC development among the Jordanian population. Risk associated withthe 1298C allele is increased in smokers and in males. The results indicate that a critical gene involved in folatemetabolism plays a modifying role in lung cancer risk, at least in the Jordanian population.