中文摘要：

目的探讨各基因单核苷酸多态性及环境因素对直肠癌所造成的影响。方法采用病例对照研究方法,运用卡方检验、单因素及多因素非条件logistic回归分析模型对直肠癌发病的危险因素进行分析,并比较各因素对直肠癌的影响程度。结果结果显示基因XRCC194位点为杂合子A/a的人群、基因XRCC7位点为纯合子A/A型的人群以及有吸烟生活习惯的人群发生直肠癌的相对危险增加。本研究还发现XRCC194,XRCC7单核苷酸多态性与直肠癌易感性的关系不受年龄、性别及吸烟等因素的影响,说明XRCC194,XRCC7等位基因是直肠癌的独立危险因素。结论吸烟及遗传因素与直肠癌的发病有一定的关联。

英文摘要：

Objective In order to detect the effects of rectal cancer caused by gene polymorphisms and environmental factors.Methods The risk factors of rectal cancer are analyzed by chi-square test,univariate and multivariate non-conditional logistic regression model,and we compare the degree of influence of factors.Results The results show that gene XRCC194 locus for the heterozygote（A/a-type）populations,gene XRCC7 locus for the homozygote（A/A-type）populations and the smoking habits populations have relatively higher risk for rectal cancer.The study also finds the relationship between gene locus XRCC194,XRCC7 single nucleotide polymorphism and rectal cancers diseases is not affected by age,gender and smoking and other factors,the result reveals gene locus XRCC194,XRCC7 are independent risk factors.Conclusion Smoking habits and genetic factors are relative to rectal cancers diseases.