【摘要】 亚甲基四氢叶酸还原酶 (MTHFR)在叶酸代谢中起重要作用 .MTHFR基因第 6 77位核苷酸的多态性(C→T)能影响其酶活性并与肿瘤易感性有关 .为比较中国北方人群MTHFRC6 77T多态性与食管鳞状细胞癌(ESCC)易感性之间的关系 ,通过高速实时聚合酶链反应 (real timePCR)和解链曲线 (meltingcurve)方法分析了 189名ESCC患者和 14 1名健康对照的MTHFRC6 77T多态性位点的基因型 .结果显示 ,健康对照组的MTHFRC/C (纯合野生 )、C/T和T/T (纯合突变 )基因型的频率分别为 17 7%、 38 3%和 4 4 0 % .ESCC患者的T/T基因型频率 (42 3% )与健康对照组无显著差异 (χ2 =0 0 89,P >0 0 5 ) ,其C/T基因型频率(49 2 % )仅略高于对照组 (χ2 =3 890 ,P <0 0 5 ) ,而患者组的C/C基因型频率 (8 5 % )显著低于健康对照组(17 7% ) (χ2 =6 37,P =0 0 12 ) .与C/T和T/T基因型相比 ,C/C基因型可显著降低ESCC的发病风险 (相对风险度的比值比 (OR) =0 4 3,95 %可信区间 (CI) =0 2 2～ 0 84 ) ,在吸烟者和有上消化道肿瘤家族史的患者中这一倾向更加明显 .研究提示 ,在中国北方人群中 ,MTHFRC6 77T纯合野生基因型对ESCC的发病起保护作用更多还原

【Abstract】 Methylenetetrahydrofolate reductase (MTHFR) is one of the important enzymes involved in folate metabolism. A single (C→T) substitution at nucleotide 677 of MTHFR gene influences the enzyme activity and is correlated with susceptibility to several tumour types. In order to compare the association of the MTHFR C677T polymorphism with susceptibility to esophageal squamous cell carcinoma (ESCC) in a Northern Chinese population, high-speed real-time PCR and melting curve analysis were used. The MTHFR C677T genotypes were determined in 189 patients with ESCC and 141 unrelated healthy controls. The results showed that the MTHFR C677T C/C, C/T and T/T genotype frequencies among healthy controls were 17 7%, 38 3%, and 44 0%, respectively. There was no significant difference in MTHFR T/T genotype frequency between ESCC patients (42 3%) and healthy controls (χ 2=0 089, P>0 05) whereas the C/T genotype frequency among ESCC patient (49 2%) was only slightly higher than that among healthy controls (χ 2=3 890, P<0 05). However, the frequency of the C/C genotype among ESCC patients (8 5%) was significantly lower than that among healthy controls (17 7%) (χ 2=6 37, P<0 05). The C/C genotype significantly reduced the risk for developing ESCC compared to the combination of the C/T and T/T genotypes (OR=0 43, 95% CI=0 22～0 84). The reduced risk was more evident among smokers and patients with family history of upper gastrointestinal cancers. It can be concluded that the MTHFR C677T homozygous wild type may play a protective role in the ESCC development in the Northern Chinese population.更多还原