亚甲基四氢叶酸还原酶基因C677T、G1793A单核苷酸多态性与散发性乳腺癌易感性的关系

目的：研究亚甲基四氢叶酸还原酶（MTHFR）基因C677T、G1793A位点单核苷酸多态性与散发性乳腺癌易感性关系。方法：采用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）方法,对200例乳腺癌患者及200例正常对照者MTHFR基因C677T、G1793A位点单核苷酸多态性进行分析,logistic回归分析不同基因型与乳腺癌风险的关系。结果：乳腺癌组MTHFR 677TT基因型频率为25.00%显著高于正常对照组的10.50%（X2=14.401,P=0.001）,CT基因型频率为44.50%低于正常对照组的54.50%,CC基因型频率在乳腺癌组和正常对照组中无差别;MTHFR 1793GA基因型频率为18.50%显著高于正常对照者的8.50%（X2=8.563,P=0.003）。乳腺癌患者MTHFR 677T和1793A等位基因频率分别为47.25%、9.25%,显著高于对照组中的37.75%、4.25%。MTHFR 677TT基因型携带者罹患乳腺癌的风险是677CC基因型携带者的2.732倍（95%CI=1.418～5.051,P=0.001）,MTHFR1793GA基因型携带者罹患乳腺癌的风险是1793GG基因型携带者的2.444倍（95%CI=1.325～4.505,P=0.003）。另外,乳腺癌组中MTHFR C677T基因多态性与肿瘤大小相关（x2=7.431,P=0.024,MTHFR G1793A基因多态性与淋巴结转移情况（x2=8.939,P=0.011）、癌组织学分级（x2=9.983,P=0.007）相关。结论：MTHFR C677T、G1793A基因多态性与散发性乳腺癌的易感性相关。

Relation between the SNPs in Methylenetetrahydrofolate Reductase Gene C677T and G1793A and the Susceptibility of Sporadic Breast Cancer

To investigate the relation between C677T and G1793A site SNPs（Single nucleotide polymorphisms） of methylenetetrahydrofolate reductase（MTHFR） gene and the susceptibility of sporadic breast cancer,the polymerase chain reaction-restriction fragment length polymorphism（PCR-RFLP） method was used to analyze the SNPs of MTHFR C677T and G1793A in 200 breast cancer patients and 200 control volunteers,and the logistic regression analysis was performed to investigate the association between different genotypes and susceptibility of breast cancer.The results showed that,the frequency of MTHFR 677TT genotype in the breast cancer group was 25.00%,which was significantly higher than 10.50% in the controls（X2=14.401,P=0.001）;The frequency of MTHFR 677CT genotype was 44.50%,which was lower than 54.50% in the controls;the frequency of MTHFR 677CC genotype was similar in both the cases and the controls;and the frequency of MTHFR 1793GA genotype was 18.50%,which was evidently higher than 8.50% in the controls（X2=8.563,P=0.003）.The allele frequencies of MTHFR 677T and 1793A in the breast cancer patients were 47.25% and 9.25%,respectively,which were significantly greater than 37.75% and 4.25% in the controls.For MTHFR C677T,the MTHFR 677TT genotype was found to be at a significant 2.732-fold increased risk of developing breast cancer（95% CI=1.418~5.051,P=0.001）,compared with that in the referent group carrying the MTHFR 677CC genotype.For MTHFR G1793A,the MTHFR1793GA genotype was found to be at a significant 2.444-fold increased risk of developing breast cancer（95% CI=1.325~4.505,P=0.004）,compared with the referent group carrying the MTHFR 1793GG genotype.Besides,the polymorphism of MTHFR C677T gene in the breast cancer group was associated with the tumor size（X2=7.431,P=0.024）,while the polymorphism of MTHFR G1793A gene was associated with lymph node metastasis（x2=8.939,P=0.011） and cancer histological grading（x2=9.983,P=0.007）.The polymorphism of MTHFR genes C677T and G1793A is correlated with the susceptibility of sporadic breast cancer.