中文摘要：

瞄准：评估是否在 mucosal 织物和某 commonmethylenetetrahydrofolate reductase (MTHFR ) 的叶酸的层次变体通过 DNA methylation 与胃的癌症的风险被联系。方法：实时 PCR 被用来学习肿瘤的表示在从有胃的癌症的 38 个病人的 76 件 mucosal 织物样品的相关基因。从有长期的表面的胃炎(CSG ) 的 34 个病人的 thegastroscopic 活体检视纸巾的样品被用作控制。在这些纸巾的叶酸的集中被 FOL ACS:180 检测自动化化合光系统。MTHFR 多型性被 PCR-RFLP 分析，并且肿瘤相关的基因的 promotermethylation 被 methylation 特定的 PCR (MSP ) 决定。结果：Folateconcentrations 比在癌的纸巾在 CSG 是显著地更高的。c-myc 的减少的表示 andmethylation 伴随了更高叶酸的集中。在有 MTHFR 677CC 的样品的 p16 (INK4A ) 的倡导者 hypermethylation 和损失是比在有 677TT 或 677CTgenotype 的样品更经常的。并且在有 MTHFR 677CT 的样品的 p21 (WAF1 ) 的倡导者 hypermethylation 和损失比 677CC 或 677TT 什么时候是在场的更经常。677CT 遗传型作为与 677CC 遗传型相比为胃的癌症显示出 non-significanthigher 风险。结论：在胃的 mucosal 织物的更低的叶酸的层次可以在 c-myc 的表示上通过 hypomethylationand 授与胃的 carcinogenesis 的更高的风险。

英文摘要：

AIM： To evaluate whether folate levels in mucosal tissue and some common methylenetetrahydrofolate reductase （MTHFR） variants are associated with the risk of gastric cancer through DNA methylation. METHODS： Real-time PCR was used to study the expression of tumor related genes in 76 mucosal tissue samples from 38 patients with gastric cancer. Samples from the gastroscopic biopsy tissues of 34 patients with chronic superficial gastritis （CSG） were used as controls. Folate concentrations in these tissues were detected by the FOL ACS： 180 automated chemiluminescence system. MTHFR polymorphisms were analyzed by PCR-RFLP, and the promoter methylation of tumor-related genes was determined by methylation-specific PCR （MSP）. RESULTS： Folate concentrations were significantly higher in CSG than in cancerous tissues. Decreased expression and methylation of c-myc accompanied higher folate concentrations. Promoter hypermethylation and loss of p16^INK4A in samples with MTHFR 677CC were more frequent than in samples with the 677TT or 677CT genotype. And the promoter hypermethylation and loss of p21 ^WAF1 in samples with MTHFR 677CT were more frequent than when 677CC or 677TT was present. The 677CT genotype showed a non-significant higher risk for gastric cancer as compared with the 677CC genotype. CONCLUSION： Lower folate levels in gastric mucosal tissue may confer a higher risk of gastric carcinogenesis through hypomethylation and overexpression of c-myc.