Dnmt1基因单核苷酸多态性与胃癌的关系

目的 探讨Dnmt1基因rs16999593、rs2228611位点单核苷酸多态性与胃癌发病易感性的关系。方法 采用病例-对照的研究方法，采集青岛地区310例胃癌患者（胃癌组）与420名健康体检者（对照组）外周血液样本，提取基因组DNA，PCR扩增目的基因片段，用DNA直接测序法对Dnmt1基因rs16999593、rs2228611位点进行基因分型，分析其与胃癌发病易感性的关系。 结果 Dnmt1基因rs16999593位点TT型、CT型和CC型在胃癌组中的频率分别为58.1%、36.1%和5.8%，在对照组中分别为66.9%、27.9%和5.2%。与野生型TT型相比，携带CT基因型者胃癌发病的风险性增加（OR＝1.494， 95%CI=1.086~2.057，P<0.05），CC基因型虽可增加胃癌发病风险，但差异无统计学意义（OR=1.277，95%CI=0.677~2.448，P>0.05）。rs2228611位点的各基因型在胃癌组和对照组间分布频率的差异无统计学意义（P>0.05）。 结论 Dnmt1基因rs16999593位点CT基因型可能增加青岛地区汉族人群胃癌发病的易感性。

Association of Dnmt1 single-nucleotide polymorphisms and risk of gastric cancer

Objective The aim of our study was to investigate whether single-nucleotide polymorphisms at loci rs16999593 and rs2228611 in the gene encoding DNA methyltransferase 1（Dnmt1） are associated with risk of gastric cancer. Methods A total of 310 patients with gastric cancer and 420 healthy controls，all Han Chinese， were genotyped at rs16999593 and rs2228611 using PCR-based DNA sequence analysis and direct DNA sequencing. Results TT，CT and CC genotypes were identified at the rs16999593 locus: respective frequencies among patients were 58.1%， 36.1% and 5.8%， compared to 66.9%， 27.9% and 5.2% among controls. The CT genotype was associated with significantly higher risk than the wild-type TT genotype（OR 1.494，95%CI 1.086 to 2.057， P<0.05）. The CC genotype was associated with marginally，but not significantly，higher risk than TT（OR 1.277，95%CI 0.677 to 2.448，P>0.05）. The frequencies of genotypes at rs2228611 did not differ significantly between patients and controls（P>0.05）. Conclusion Polymorphism at Dnmt1 rs16999593 is associated with elevated risk of gastric cancer among Han Chinese in Qingdao．