超氧化物歧化酶2基因rs4880位点单核苷酸多态性与食管癌易感性的关系

目的探讨超氧化物歧化酶2（SOD2）基因rs4880位点单核苷酸多态性与食管鳞状细胞癌发生的关系。方法 收集2013年10月至2015年11月经病理确诊的380例食管鳞状细胞癌患者（食管癌组）的外周静脉血用基质辅助激光解吸／电离飞行时间质谱法（MALDI TOF MS）分析SOD2 rs4880的基因分型，同时收集380例非肿瘤患者（对照组）的外周静脉血进行对比。采用Hardy-Weinberg平衡分析SOD2 rs4880的遗传平衡情况，采用两分类Logistic多元回归比较两组SOD2 rs4880基因型和等位基因的分布差异，并计算比值比（OR）及其95％可信区间（95％CI）来评价发生食管鳞状细胞癌的相对风险。结果 食管癌组和对照组的SOD2 rs4880基因型频率均符合Hardy-Weinberg平衡。食管癌组和对照组的SOD2 rs4880 T＞C 3种基因型TT、TC、CC的分布频率分别为71.84％、22.37％、3.68％和74.74％、20.79％、3.42％，两组基因型分布频率的差异无统计学意义（P＞0.05）。两分类Logistic多元回归分析的结果显示：（1）与携带SOD2 rs4880 TT基因型的个体相比较，SOD2 rs4880 TC基因型、CC基因型发生食管癌的风险升高1.12倍，但差异无统计学意义（OR=1.12，95%CI：0.79～1.59，P＞0.05；OR=1.12，95%CI：0.52～2.43，P＞0.05）；（2）隐性模型中相对于TT+TC基因型，携带纯合突变CC基因型发生食管癌的风险升高1.09倍，差异无统计学意义（OR=1.09，95%CI：0.51～2.36，P＞0.05）；（3）经调整年龄、性别、吸烟及饮酒状态后，与携带SOD2 rs4880 TT基因型的个体相比较，携带SOD2 rs4880 CC基因型发生食管癌的风险升高1.10倍，差异亦无统计学意义（OR=1.10，95%CI：0.50～2.39，P＞0.05）。结论 SOD2 rs4880位点基因多态性可能不是食管鳞状细胞癌发生的易感因素，需要进一步扩大样本量予以证实。

Association of SOD2 gene polymorphism with susceptibility to esophageal squamous cell carcinoma

ObjectiveTo investigate the relationship between superoxide dismutase 2（SOD2） gene single nucleotide polymorphism（SNP）of rs4880 and the susceptibility to esophageal squamous cell carcinoma. Methods Peripheral blood samples were collected from 380 patients with pathologically confirmed esophageal squamous cell carcinoma（esophageal cancer group）and 380 patients without cancers（control group）form October 2013 to Nevember 2015. Genotypes were determined by the MALDI TOF MS method in 380 cases of esophageal cancer group and 380 cases of control group. Hardy Weinberg equilibrium analysis was used to analyze the genetic balance of SOD2 rs4880 in the esophageal cancer group and control group. Two classification logistic multiple regression analysis between the esophageal cancer group and control group in terms of rs4880 T＞C were made to calculate the odds ratio （OR） and its 95％ confidence interval （95％CI） to evaluate the relationship between SNPs and susceptibility to esophageal cancer. Results The distribution of 380 esophageal squamous cell carcinoma patients and 380 patients without cancers regarding SOD2 polymorphism of rs4880 T＞C were in accordance with the Hardy Weinberg equilibrium. The SOD2 rs4880 T＞C genotype frequencies were 71.84％（TT）， 22.37％（TC）， 3.68％（CC） in the esophageal cancer group and 74.74％（TT）， 20.79％（TC）， 3.42％（CC） in the control group respectively， there was no significant difference between the esophageal cancer group and the control group （P＞0.05）. Logistic regression analyses revealed that compared with SOD2 rs4880 TT gene type， SOD2 rs4880 TC and CC genotypes increased the risk of esophageal squamous cell carcinoma to 112 folds, but the difference was not statistically significant （OR=1.12，95%CI：0.79-1.59，P＞0.05； OR=1.12，95%CI：0.52-2.43，P＞0.05）. Compared with SOD2 rs4880 TT+TC genotype， SOD2 rs4880 CC genotype increased the risk of esophageal squamous cell carcinoma to 1.09 folds, but the difference was not statistically significant（OR=1.09，95%CI：0.51-2.36，P＞0.05）. After adjusting age, sex, smoking and drinking status, SOD2 rs4880 CC genotype increased the risk of esophageal squamous cell carcinoma to 1.10 folds compared with SOD2 rs4880 TT genotype, but the difference was not significant（OR=1.10，95%CI：0.50-2.39，P＞0.05）. Conclusion SOD2 rs4880 T＞C polymorphism may not serve as a protective biomarker of esophageal squamous cell carcinoma susceptibility. Further studies are warranted to verify these results.