目的: 单核苷酸多态性(single nucleotide polymorphisms，SNPs)，主要是指在基因组水平上由单个核苷酸的变异所引起的 DNA 序列多态性，是造成个体对肿瘤易感性差异的重要因素。本实验探讨9 个功能性单核苷酸多态:FAS-670G/A、FAS -1377G/A、FASL-844T/C、STK15 Phe31I1e、COX-2 -1290A/G、COX-2 -1195G/A、MTHFR -677C/T、MTHFR-1298A/C 和 MMP-2 -735C/T多态，在汉族和蒙古族人群中与肿瘤遗传易感性之间的关系。方法:应用聚合酶链反应(polymerase chain reaction,PCR) 和限制性片段长度多态性(restriction fragment length polymorphism, RFLP) 分析方法，检测了 132 例蒙古族食管癌、400 例蒙古族正常对照不同位点基因型的分布， 并将结果与已有的汉族人群基因分型资料比较。多因素 logistic 回归分析研究了9 个多态位点在汉族和蒙古族与食管癌患病风险的关系。结果: 比较蒙古族与汉族正常人上述 9 个基因多态等位基因频率，发现FASL -844 T/C 多态、COX-2 -1195 G/A 多态和 MTHFR -677C/T 多态的基因型频率分布在汉族和蒙古族之间具有显著性差异，P值分别为 0.0001、0.0022和<0.0001。上述9个多态与食道癌患病风险的相关性分析结果表明，在汉族人群中，除COX-2 -1290 A/G 以外的8个多态位点均能不同程度地影响食管癌发病风险。而在蒙古族人群中，STK15 Phe31I1e多态与食道癌发病风险相关性与汉族人群结果相反，而其余 8个多态位点在病例和对照中的基因型频率不存在显著差异。 结论: 蒙古族与汉族人基因遗传变异与食管癌易感性可能存在着不同。尚需扩大样本量研究蒙古族食管癌易感性因素。

Single nucleotide polymorphisms (SNPs) are the most common form of genetic variation in humans, having their least common nucleotide found in greater than 1 percent of the population.It may be an important susceptibility factor for cancer. To examine the association between the functional polymorphisms and the susceptibility of esophageal cancer, we studied nine polymorphisms,including FAS-670G/A、FAS.-1377G/A、FASL-844T/C、STK15 Phe31Ile、COX-2-1290A/G、COX-2-1195G/A、MTHFR-677C/T、MTHFR-1298A/C、MMP-2-735C/T,and analysed the genotype frequency of these polymorphisms in the Han nationality and the Mongolia. These polymorphisms were detected by a polymerase chain reaction-based restriction fragment length polymorphism assay (PCR-RFLP) in a case-control study of 132 incident cases with esophageal cancer and 400 cancer-free controls of Mongolia. The genotype frequencies were compared with these of the Han nationality which were published previously. We found that the genotype frequencies of FASL -844T/C, COX-2 -1195G/A and MTHFR -677C/T are significantly different between the two nationalities (P=0.0001, P=0.0022, P<0.0001.respectively). In the Han nationality, all the polymorphisms in this research were associated with the esophageal cancer risk except COX-2 -1290A/G.In the Mongolia, STK15 Phe31Ile was associated with the esophageal cancer risk, but it was opposite to the result from Han nationality. The other eight polymorphisms were not the susceptibility of esophageal cancer. These observations indicated that the susceptibility of esophageal cancer may be different between the Han nationality and the Mongolia. It is necessary to study the susceptibility of esophageal cancer in a large sample of Mongolia.