MTHFR C677T基因型、烟酒嗜好及其相互作用与胃癌

目的研究亚甲基四氢叶酸还原酶(MTHFR)基因C677T多态性及其和烟酒茶嗜好相互作用与胃癌易感性的关系.方法在上消化道癌高发区淮安市进行了一个病例-对照研究(胃癌107例,人群对照200例),调查研究对象的生活习惯,采用PCR-RFLP技术检测研究对象的MTHFR基因型.结果①胃癌组中MTHFR变异型等位基因携带者的比例为79.4%,显著高于对照组的68.5%(x2=4.15,P=0.0416).MTHFR变异型等位基因携带者发生胃癌的危险性显著升高(OR=1.78,95%CI0.99～3.22;性别、年龄吸烟和饮酒习惯调整OR=1.79,95%CI1.01～3.19).②与携带MTHFR野生基因型的不吸烟者相比,携带变异型基因且伴有吸烟习惯者发生胃癌的OR为7.82(95%CI2.43～25.19),伴有经常饮酒的习惯者发生胃癌的OR为2.87(95%CI1.28～6.47).与不吸烟、不经常饮酒的野生型MTHFR基因携带者相比,伴有吸烟和经常饮酒习惯的变异型基因携带者发生胃癌的OR为8.67(95%CI2.12～40.94).结论MTHFRC677T变异型基因型与胃癌的易感性有关;吸烟和饮酒与MTHFR变异基因型在胃癌发生中有明显的协同作用.调查生活习惯同时检测MTHFR基因型有助于胃癌高危人群和个体的筛选.     

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。     

亚甲基四氢叶酸还原酶基因C677T多态性与食管癌易感性的关系

目的　研究亚甲基四氢叶酸还原酶 (MTHFR)基因C6 77T多态性及其和烟酒茶嗜好相互作用与食管癌易感性的关系。方法　在上消化道癌高发区淮安市进行了一个病例 对照研究 (食管癌 93例 ,人群对照 2 0 0例 ) ,调查研究对象的生活习惯 ,采用PCR RFLP技术检测研究对象的MTHFR基因型。结果　 1.食管癌组和对照组中MTHFR变异型等位基因携带者分别占 6 6 .7%和 6 8.5 % ,其差异无统计学显著性。 2 .在MTHFR野生型基因携带者中 ,吸烟习惯显著增加食管癌发生的危险性 (OR =3.2 2 ,95 %CI:1.0 9～ 9.5 3)。在MTHFR变异型基因携带者中 ,经常饮酒者发生食管癌的危险性显著升高 (OR =2 .30 ,95 %CI :1.0 2～ 2 .5 7)。在野生型和变异型基因携带者中 ,有饮茶习惯者发生食管癌的危险性均显著降低。结论　MTHFR基因的多态性影响吸烟、饮酒与食管癌之间的关系。调查生活习惯、同时检测MTHFR基因型有助于食管癌的预防。     

乙醇和乙醛脱氢酶基因多态与男性结直肠癌的易感性

目的研究乙醇脱氢酶2(ADH2)和乙醛脱氢酶2(ALDH2)基因多态及饮酒习惯与男性结直肠癌易感性的关系。方法在江苏省进行了一项病例-对照研究(结直肠癌患者190例,人群对照222名),调查研究对象的生活习惯,抽取静脉血,提取白细胞DNA,采用聚合酶链反应(PCR)和变性高效液相色谱法(DHPLC)检测研究对象的ADH2Arg47His(G-A)和ALDH2Glu487Lys(G-A)的基因型。结果①ADH2A/A和ALDH2G/G基因型显著增加结直肠癌的易感性。在调整了年龄和吸烟状况后,ADH2A/A基因型者与携带G等位基因者相比,发生结直肠癌的危险性上升到1.61(95%CI:1.09~2.38);ALDH2G/G基因型者与携带A等位基因者相比,发生结直肠癌的危险性上升到1.79(95%CI:1.19~2.69)。②与ADH2G和ALDH2A等位基因携带者相比,同时携带ADH2A/A和ALDH2G/G基因型者发生结直肠癌的OR值上升到3.05(95%CI:1.67~5.57);与不饮酒的ADH2G等位基因携带者相比,拥有ADH2A/A基因型的饮酒者的OR值上升到3.44(95%CI:1.84~6.42);与不饮酒的ALDH2A等位基因携带者相比,拥有AL-DH2G/G基因型的饮酒者的OR值上升到2.70(95%CI:1.57~4.66)。结论ADH2和ALDH2基因多态性与男性结直肠癌的易感性相关。ADH2,ALDH2基因多态之间以及基因多态与饮酒习惯之间,在结直肠癌发生中存在显著的协同作用。     

胸苷酸合成酶基因多态性及烟酒茶嗜好与贲门癌易感性的关系

目的 :研究胸苷酸合成酶TS3′ UTR多态性及其和烟酒茶嗜好相互作用与贲门癌易感性的关系。方法 :在上消化道癌高发区淮安市进行了一个病例对照研究 (贲门癌 89例 ,人群对照 2 2 3例 ) ,调查研究对象的生活习惯 ,采用PCR RFLP技术检测研究对象的TS 3′ UTR基因型。结果 :贲门癌组TS 6/ 6bp、 6/-6bp和 -6/-6bp基因型频率分别为7 9%、43 8%和 48 3 % ,与对照组( 8 1%、5 4 3 %和 3 7 7% )相比差异无统计学意义。与携带TS 6bp等位基因且不吸烟、每周饮酒 <2次和饮茶者相比 ,在吸烟、每周饮酒≥ 2次和不饮茶者中 ,携带TS -6/-6bp基因型者发生贲门癌的危险性显著上升 ,调整后的OR分别为 3 99( 95 %CI:1 5 1～ 10 5 0 )、3 2 2 ( 95 %CI :1 2 1～8 5 5 )和 6 14 ( 95 %CI:2 3 9～ 15 77)。结论 :TS 3′ UTR基因多态性影响吸烟、饮酒和饮茶与贲门癌之间的关系     

亚甲基四氢叶酸还原酶基因型、饮食习惯与胃癌的易感性

目的：研究亚甲基四氢叶酸还原酶（MTHFR）基因C677T多态性、饮食习惯与胃癌易感性的关系。方法：在上消化道癌高发区淮安市楚州区进行了一个病例－对照研究（胃癌107例，人群对照200例），调查研究对象的生活习惯，用PCR－RFLP技术检测研究对象的MTHFR基因型。结果：（1）胃癌组中MTHFR C／T或T／T型基因携带者占79．4％，显著高于对照组的68．5％（χ^2=4.15,P=0.0416,OR=1.78,95% CI:0.99-3.22;调整OR＝1．79，95％CI：1．01－3．19）。（2）在不经常吃大蒜、大葱者中，MTHFR C／T或T／T型基因携带者发生胃癌的危险性显著升高。在不饮茶者中或在经常吃肉者中，携带MTHFRC／T或T／T型基因者发生胃癌的危险性也显著上升。结论：MTHFR C677T基因型与胃癌的易感性有关；不同饮食习惯对MTHFR C677T基因型与胃癌易感性之间的关系有影响。     

MTHFR基因1298 A→C多态与新疆哈萨克族食管癌风险关系的研究

目的:探讨亚甲基四氢叶酸还原酶(MTHFR)基因1298A→C多态及其和生活习惯相互作用与新疆哈萨克族食管癌风险的关系。方法:收集经组织病理学确诊的哈萨克族食管鳞癌新发病例88例外周血液标本,提取DNA;72名健康哈萨克族人群作为对照,同时调查每个研究对象的吸烟、饮酒情况。用PCR-RFLP技术检测研究对象的MTHFR1298A→C基因多态性。结果:病例组MTHFR1298AA、AC和CC基因型分别为63.64%、34.09%和2.27%,与对照组的72.22%、27.78%和0相比差异无统计学意义,χ2MH=2.57,P=0.276。MTHFR1298AA、MTHFR1298AC基因型与哈萨克族食管癌的发生无显著相关性,P>0.05。病例组与对照组1298C等位基因频率分别为0.19和0.14,两组间差异无统计学意义,P>0.05。与携带MTH-FR1298AA基因型的不吸烟者相比,携带MTH-FR1298C等位基因且有吸烟习惯者的性别、年龄以及饮酒习惯调整OR值为2.353(95%CI为0.892～6.210)。与携带MTHFR1298AA基因型的不饮酒或不常饮酒者相比,携带MTHFR1298C等位基因并伴有经常饮酒的习惯者发生食管癌的危险性也显著增高,其性别、年龄以及饮酒习惯调整OR值为1.860(95%CI为0.585～5.915)。结论:叶酸摄入不足是新疆哈萨克族食管癌的危险因素;MTHFR1298AC和CC基因型对吸烟、饮酒习惯增加食管癌发生风险作用有放大效应。     

生长激素1基因多态性和烟酒习惯与结直肠癌易感性的关系

目的:研究生长激素1(growth hormone1,GH1)基因T1663A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439名),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GH1T1663A基因型。结果:1)GH1T/T、T/A和A/A基因型分布频度在结直肠癌组分别为42.2%、46.7%和11.1%,对照组分别为38·1%、45·9%和16·0%,两组差异无统计学意义,χ2MH=3·907,P=0·142。但在调整性别、年龄、吸烟和饮酒习惯后,A/A基因型者与T/T基因型者相比,发生结直肠癌的危险性显著降低(OR=0·88,95%CI:0·78~0·99,P=0·0287)。2)多因素分析结果显示,饮酒者患结直肠癌的危险性显著增高(OR=1·96,95%CI:1·34~2·86,P=0·0005),A/A基因型与降低结直肠癌的危险性有关,而吸烟与增加或降低结直肠癌的危险性无显著相关。3)GH1基因多态与吸烟、饮酒相互作用的分层分析发现,在不吸烟者中,GH1A/A基因型者与T等位基因型者相比,发生结直肠癌的危险性显著降低(性别和年龄调整OR=0·50,95%CI:0·27~0·93);在不饮酒者中,GH1A/A基因型者发生结直肠癌的调整OR为0·56(95%CI:0·32~0·99)。结论:T1663A GH1基因的A/A基因型可降低结直肠癌易感性,特别是在不吸烟和不饮酒者中。     

亚甲基四氢叶酸还原酶基因多态性与中国人群食管癌易感性的Meta分析

目的运用Meta分析的方法综合评价中国人群中亚甲基四氢叶酸还原酶（MTHFR）基因多态性与食管癌发病的相关性。方法通过计算机文献检索中国生物医学文献数据库(CBM) 和PubMed数据库,并结合文献追溯、网上查询(www.baidu.com; www.google.cn)的方法,收集所有关于MTHFR基因多态性与食管癌易感性的病例对照研究或队列研究。以食管癌组与对照组人群基因型分布的OR值为效应指标,各资料间进行一致性检验,以确定采用固定或随机效应模型进行合并分析。发表偏倚用漏斗图和Egger’s线性回归检验来评估。结果共有在国内外发表的相关文献10篇纳入分析,Meta分析结果表明：MTHFR C677T基因多态和MTHFR A1298C基因多态合并OR值及其95%CI分别为1.97（1.69,2.30）,0.84(0.66,1.08)。按是否吸烟进行分层发现吸烟组中MTHFR 677CT/TT基因型与食管癌有关(OR=2.57,95%CI:1.73~3.80),而不吸烟组中未见MTHFR 677CT/TT基因型与食管癌存在关联（OR=1.33,95%CI:0.94~1.88)。结论中国人群MTHFR C677T基因多态性与食管癌易感性有关,MTHFR A1298C基因多态性与食管癌易感性无统计学关联。吸烟可能会增加MTHFR C677T基因型个体患食管癌的危险性。     

Methylenetetrahydrofolate reductase (MTHFR) genotype, smoking habit, metastasis and oral cancer in Taiwan

The aim of this study was to evaluate the association and interaction of genotypic polymorphism in methylenetetrahydrofolate reductase (MTHFR) with smoking habits and oral cancer in Taiwan. Two well-known polymorphic variants of MTHFR, C677T (rs1801133) and A1298C (rs1801131), were analyzed in association with oral cancer risk, and their joint effects with individual smoking habits on oral cancer risk are discussed. In total, 620 oral cancer patients and 620 non-cancer controls in central Taiwan were recruited and genotyped. The MTHFR C677T genotype, but not the A1298C, was differently distributed between the oral cancer and control groups. The T allele of MTHFR C677T was significantly more frequently found in controls than in oral cancer patients. Joint effects of smoking and MTHFR C677T genotype significantly affected oral cancer susceptibility. The MTHFR C677T CT and TT genotypes in association with smoking conferred lower odds ratios of 0.66 and 0.54 (95% confidence interval=0.49-0.82 and 0.39-0.86), respectively. Those patients with MTHFR C677T CT and TT genotypes also had a lower risk of oral cancer metastasis. MTHFR C677T genotype may have joint effects with smoking on oral carcinogenesis, and may be a useful biomarker for prediction and prognosis of oral cancer.     

Methylenetetrahydrofolate reductase polymorphisms/haplotypes and risk of gastric cancer: a case-control analysis in China

Studies have suggested that low dietary folate intake is associated with an increased risk of gastric cancer. Methylenetetrahydrofolate reductase (MTHFR) is involved in folate metabolism and influences DNA methylation and nucleotide synthesis. MTHFR is highly polymorphic and the variant genotypes result in decreased MTHFR enzyme activity and lower plasma folate level. We hypothesized that three MTHFR common variants (i.e. C677T, A1298C and G1793A) and their haplotypes are associated with the risk of gastric cancer. To test this hypothesis, we genotyped these polymorphisms in a population-based case-control study of 320 incident gastric adenocarcinoma cases and 313 cancer-free controls in a Chinese population. Consistent with our previous observations, the 677TT genotype was associated with a significantly increased risk for gastric cancer (adjusted OR =1.79, 95% CI =1.02-3.15) compared with the 677CC genotype; the association was more evident for gastric cardia adenocarcinoma (adjusted OR =2.60, 95% CI =1.30-5.21). When we used the haplotype analyses and assumed MTHFR 677T, 1298C and 1793A as risk alleles, individuals with 6 variant alleles had a significantly (4.64-fold) increased risk for gastric cardia adenocarcinoma (OR =4.64, 95% CI =1.34-16.01) compared with those having 0-2 variants. These findings suggest that the MTHFR common variants and their haplotypes may play a role in the etiology of gastric cancer, particularly gastric cardia adenocarcinoma. Future studies using large sample sizes and incorporating detailed data on dietary folate intake and related serological measurements are warranted to confirm our findings.     

MTHFR基因遗传多态与食管癌贲门癌易感性的关系

目的:探讨食管癌高发区亚甲基四氢叶酸还原酶(MTHFR)基因单核苷酸多态与食管癌、贲门癌发病风险的关系。方法:以聚合酶链反应和限制性片段长度多态方法,分析584例食管癌患者、467例贲门癌患者和540例正常对照的MTHFR基因C677T基因型及其与食管癌、贲门癌发病风险的相关性。结果:在正常对照中,MTH-FR677CC、CT、TT基因型频率分别为22.1%、43.3%和34.6%,在食管癌患者中分别为12.5%、45.0%和42.5%(P=0.000);在贲门癌患者中分别为15.8%、43.5%和40.7%(P=0.024)。多因素分析发现,携带677TT基因型和677CT基因型的个体发生食管癌的风险分别是677CC基因型的2.36倍和1.76倍,发生贲门癌的风险分别是1.34倍和1.23倍。结论:MTHFR单核苷酸多态是食管癌高发区食管癌和贲门癌的遗传易感性因素。     

Impact of one-carbon metabolism-related gene polymorphisms on risk of lung cancer in Japan: a case control study

There is substantial evidence that the decreased risk of lung cancer with high intake of vegetables and fruits is linked to folate as a specific nutrient. Functional polymorphisms in genes encoding one-carbon metabolism enzymes, methylenetetrahydrofolate reductase (MTHFR C677T and A1,298C), methionine synthase (MTR A2,756G), methionine synthase reductase (MTRR A66G) and thymidylate synthase, influence folate metabolism and thus might be suspected of impacting on lung cancer risk. We therefore conducted a case-control study with 515 lung cancer cases newly and histologically diagnosed and 1,030 age- and sex-matched non-cancer controls to clarify associations with these five polymorphisms according to lung cancer subtype. Gene-environment interactions with smoking and drinking habit and folate consumption were also evaluated by logistic regression analysis. None of the polymorphisms showed any significant impact on lung cancer overall risk by genotype alone, but on histology-based analysis increase in MTHFR 677T and 1,298C alleles was associated with reduced risk of squamous/small cell carcinoma (P = 0.029), especially among heavy smokers (P = 0.035), whereas the MTHFR 677TT genotype was linked to decreased risk for these subtypes among heavy drinkers (odds ratio = 0.17, 95% confidence interval: 0.03-0.98). In addition, we found interactions between the MTRR A66G polymorphism and smoking (P = 0.015) and the MTHFR A1,298C polymorphism and alcohol consumption (P = 0.025) for risk of lung cancer overall. In conclusion, the results suggest that MTHFR polymorphisms contribute to risk of squamous/small cell carcinomas of the lung, along with possible interactions among folate metabolism-related polymorphisms and smoking/drinking habits. Further evaluation is warranted.     

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.     

Polymorphisms of 5,10-methylenetetrahydrofolate reductase and risk of gastric cancer in a Chinese population: a case-control study

Low dietary folate intake has been associated with increased risk of gastric cancer. The 5,10-methylenetetrahydrofolate reductase (MTHFR) involved in folate metabolism has 2 variants, C677T and A1298C, that result in decreased MTHFR activity and lower plasma folate levels. Therefore, we hypothesized that these 2 variants play a role in gastric carcinogenesis. We tested this hypothesis in a Chinese population-based case-control study of 187 histopathologically confirmed gastric cancer cases and 166 healthy controls frequency-matched by age (+/-5 years), gender and residential area. The 677TT genotype was associated with increased risk for gastric cancer [adjusted odds ratio (OR) = 1.87, 95% confidence interval (CI) = 1.00-3.48] compared to the 677CC genotype. This association was more pronounced for gastric cardia cancer (adjusted OR = 2.47, 95% CI = 1.14-5.32). However, no evidence was found for risk associated with the MTHFR A1298C polymorphism. Our findings support the hypothesis that MTHFR C677T variants contribute to gastric carcinogenesis, particularly in gastric cardia. Larger studies incorporating dietary folate intake and serum levels are needed to confirm our findings.     

Significant association of methylenetetrahydrofolate reductase single nucleotide polymorphisms with prostate cancer susceptibility in taiwan

Prostate cancer is the most common cause of cancer death in men and is a major health problem worldwide. Methylene tetrahydrofolate reductase (MTHFR) plays an important role in folate metabolism and is also an important source of DNA methylation and DNA synthesis (nucleotide synthesis). To assess the association and interaction of genotypic polymorphisms in MTHFR and lifestyle factors with prostate cancer in Taiwan, we investigated two well-known polymorphic variants of MTHFR, C677T (rs1801133) and A1298C (rs1801131), analyzed the association of specific genotypes with prostate cancer susceptibility, and discussed their joint effects with individual habits on prostate cancer risk. In total, 218 patients with prostate cancer and 436 healthy controls recruited from the China Medical Hospital in central Taiwan were genotyped for these polymorphisms with prostate cancer susceptibility. We found the MTHFR C677T but not the A1298C genotype was differently distributed between the prostate cancer and control groups. The T allele of MTHFR C677T conferred a significantly (p=0.0011) decreased risk of prostate cancer. As for the A1298C polymorphism, there was no difference in distribution between the prostate cancer and control groups. Gene interactions with smoking were significant for MTHFR C677T polymorphism. The MTHFR C677T CT and TT genotypes in association with smoking conferred a decreased risk of 0.501 (95% confidence interval=0.344-0.731) for prostate cancer. Our results provide the first evidence that the C allele of MTHFR C677T may be associated with the development of prostate cancer and may be a novel useful marker for primary prevention and anticancer intervention.     

Methylenetetrahydrofolate reductase genotypes, dietary habits and susceptibility to stomach cancer

Objective To study the relation among methylenetetrahydrofolate reductase (MTHFR) C677T genotypes, dietary habits and the risk of stomach cancer (SC). Methods A case-control study was conducted with 107 cases of SC and 200 population -based controls in Chuzhou district, Huaian. Jiangsu province, China. The epidemiological data were collected, and DNA of peripheral blood leukocytes was obtained from all of the subjects, MTHFR genotypes were detected by PCR-RFLP. Results (1) The prevalence of the MTHFR C/T or T/T genotypes was found to be significantly different between controls (68.5%) and SC cases (79.4%. P =0.0416), the increased risk had an adjusted OR of 1.79 (95%CI: 1.01 -3.19). (2) Among subjects who had a low intake of garlic or Chinese onion, MTHFR C/T or T/T genotypes significantly increased the risk of developing SC. Among non-tea drinkers or among subjects who had a frequent intake of meat, the carriers of the MTHFR C/T or T/T genotypes had a higher risk of SC than individuals with the C/C type MTHFR. Conclusion The polymorphism of MTHFR C677T was associated with increased risk of developing SC, and that individuals with differing genotypes may have different susceptibilities to SC, based on their exposure level to environmental factors. This work was supported in part by a Grant-in Aid for International Scientific Research, Special Cancer Research (No.08042015, 11137311) from the Ministry of Education, Science, Sports, Culture and Technology, Japan.