Background Cytochrome P450 2E1 （CYP2E1） has an important role in the metabolic activation of precarcinogens such as N-nitrosoamines and other low relative molecular mass, organic compounds. This study examined whether CYP2E1 Rsal and Dral polymorphism are associated with susceptibility to esophageal squamous cell carcinoma and the correlation between the genotypes and expression levels of CYP2E1 mRNA.Methods Seventy-seven patients with newly diagnosed, untreated esophageal squamous cell carcinoma and 79 healthy controls matched in age, gender and residence were recruited for the control study. An Rsal polymorphism in the 5＇-flanking region and a Dral polymorphism in the sixth intron of the CYP2E1 gene, which could possibly affect its transcription, were determined in this study by polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP） and mRNA level of CYP2E1 was measured by quantitative real-time reverse transcription PCR.Results No significant association of Rsal or Dral polymorphism of CYP2E1 with susceptibility of esophageal squamous cell carcinoma were demonstrated （OR=1.67, 95%CI： 0.89-3.15, P=0.11; OR=1.11, 95%CI： 0.59-2.09, P=0.74, respectively）. With SHEsis software, no linkage disequilibrium was detected between Rsal and Dral polymorphism （D＇=0.528, r^2=0.27）. When combined Rsal polymorphism with Dral polymorphism, the association between that carrying c2 allele and DD genotype and the risk for esophageal squamous cell carcinoma were found （OR=5.77, 95%CI： 1.65-20.22）. Compared with the normal controls, the mRNA levels with Rsal polymorphism, Dral polymorphism, or any combined genotypes in cases showed no statistical difference.Conclusions This study suggests that carrying c2 allele and DD genotype conferreded an elevated risk for esophageal squamous cell carcinoma. There was no significant statistical relationship between the genotypes c1/c2, D/C, or the combined allele and mRNA expression.
[目的]应用全血PCR直接扩增技术检测准安汉族人群亚甲基四氢叶酸还原酶基因MTHFRC677T多态性并分析其地理分布特征，评价该技术在大规模现场人群基因多态性筛检中的应用价值。[方法]应用全血PCR直接扩增技术分析205例淮安汉族健康个体MTHFRC677T的基因型分布频率，并与传统的聚合酶链反应一限制性片段长度多态性（Polymerase chain reaction and restriction fragment length polymorphism，PCR—RFLP）技术检测结果进行比对。并将检测结果与已报道的不同地区汉族人群资料进行比较。[结果]全血PCR直接扩增技术与传统PCR—RFLP法测定MTHF RC677T多态性的分布频率具有高度一致性（Kappa=0.946，95％CI：0，906～0．985o结果表明淮安汉族人群MTHFRC677T的基因型频率分别为CC32，68％、CT46．83％、TY20.49％；C和T等位基因频率分别为56.10％和43．90％；结合其他9个地区的汉族人群MTHFR677T等位基因频率的趋势性x^2矿检验，发现MTHFR677T的分布随地理纬度的降低，T等位基因频率也降低（P=0．001。[结论]全血PCR直接扩增技术简便易行，适用于人群基因多态性的快速筛检。在所研究的10个中国汉族人群中MTHFRC677T多态性显示与不同地理纬度的地区分布有统计学相关性。
