【作者】 李英；

【导师】 高元勋；

【作者基本信息】 郑州大学 ， 呼吸内科学， 2004， 硕士

【摘要】 肺癌(Lung Cancer，LC)是世界上最常见的六大恶性肿瘤之一，占所有肿瘤发病率的19％，死亡率的29％，我国肺癌的死亡率已跃居第一位。肿瘤流行病学研究证实：吸烟是肺癌发生最重要的原因，吸烟人群患肺癌的相对危险性比不吸烟人群高20倍之多，但只有少于20％吸烟者有患肺癌的危险性，显然机体对烟草烟雾中致癌物的敏感性有很大个体差异。近年来的研究发现，肺癌的发生是环境暴露与遗传因素复杂交互作用的结果，外源性致癌物的代谢、DNA损伤与修复、细胞周期调控、细胞死亡与分化以及机体免疫监控等方面存在的基因多态现象，对个体肺癌易感性差异有显著影响。在外源性致癌物的代谢活化、DNA损伤与修复这两个环节中，药物代谢酶CYPs和GSTs最具代表性。研究发现，CYP1A1和GSTM1基因多态与肺癌的易感性密切相关。CYP1 A1多态在CYP1 A1基因的3′非编码区聚腺苷酸下游264bp处，由碱基T→C变异导致酶活性增高。GSTM1有缺陷型和功能型两种多态，缺陷型产生大量无活性酶，导致机体解毒能力下降。 我们假设，在河南地区人群中CYP1A1 m1基因突变所造成的酶活性增高及GSTM1表达缺陷，将会通过干扰正常烟草致癌物的代谢和清除过程而影响机体患肺癌的危险性或易感性。本课题对该地区人群进行回顾性“病例—对照”研究，分析此二种基因多态与支气管肺癌癌变的关系，来探讨其在肺癌诊断方面的价值，并为高危人群的筛选和防治提供有意义的信息和手段。 材料和方法： 实验组包括103例肺癌患者，所有病例均来自河南籍汉族人群，于2003年3～8月间在郑州大学第一、二附属医院气管镜室检查，经纤维支气管镜活检和／或刷检和／或灌洗液脱落细胞病理学检查确诊，为首次确诊病例，郑州大学20(只年硕士研究生毕业论文细胞色素P450 IAI和谷耽甘肚硫转移酶Ml基因多态与肺癌易感性关系研究并经综合临床分析，排除有其它恶性肿瘤病史者。正常对照组共138例，随机选自该地区志愿参与健康体检的人群，与病例组年龄性别相匹配。所有入选者均经详细问卷调查，以查明其疾病史并排除有肿瘤病史者。 DNA提取试剂采用美国Gentra公司的产品，以盐析法从支气管肺泡灌洗液或血凝块残留液中提取基因组DNA，采用PcR法及基于PcR基础上的限制性片段多态检测法(PCR一RFLP)，对各基因型进行检验和区分。采用回顾性“病例一对照”试验设计，所得的对照组数据采用Fisher Exact扩检验进行验证，确定其各基因型分布是否符合Hardy一weinberg平衡;危险度计算采用非条件性逻辑斯谛回归模型(Uneonditional logisticregression models)分别对年龄、性别进行校正后计算比数比(odds Ratios，OR)及95%可信区间(Confidential Intervals，Cl);以上计算均由SPSS10.0 (USA)统计软件进行分析，检验显著性水准均采用a=0.05。结果: 1.CYPIAI的wl野生型、ml突变型等位基因频率在对照组分别为72%和28%，在肺癌组分别为57%和43%，ml突变型等位基因频率在病例组明显高于对照组，两组间分布经扩检验差别显著;GsTMI的缺陷型基因(D)频率在对照组、肺癌组分别为44%和61%，其比例在病例组明显高于对照组，经扩检验差别显著。 2.对于CYPIAI，其各基因型的分布频率在对照组分别为A型 (wl/wl)52.9%、B型(ml/wl)39.1%、C型(ml/ml)8%，在肺癌组分别为A型(wl/wl)26.2%、B型(mr/wl)62.1%、C型(ml/ml)n.7%，两组间分布经扩检验差别显著。GsTMI缺陷型(D)和功能型(F)基因分布频率在对照组分别为44.2%、55.8%，在肺癌组分别为61.2%、38.8%，两组间基因型的分布经扩检验差别显著。 各基因型在对照组的分布均符合群体遗传学Hardy一weinberg平衡 (GSTMI，P== 0.291;CYPIAI，P=0.280)，表明研究对象的选择无群体遗传学偏差。 3.我们将CYP IAI(wl/wl)野生纯合型基因(A型)作为参考组，考查杂合型(B型)和纯合突变型(C型)患肺癌的危险度。与参考组基因型相比，B基因型患肺癌的危险度升高3.190倍(95%Cl，1.782一5.713)，郑州大学2仪抖年硕士研究生毕业论文细胞色素P450 IAI和谷脱甘肤硫转移酶Ml基因多态与肺癌易感性关系研究C基因型患肺癌的危险度升高2.607倍(95%Cl，x.O18一6.674)，二者合计患肺癌的危险度升高3.161倍(95%，Cl，1.821一5.489)，三者经统计学分析差别显著。 4.与GSTMI(F)型基因相比，GSTMI(D)型基因携带者患肺癌的危险度升高2.085倍(95%Cl，1.225~3.551)，具有显著性统计学意义。 5，将兼有GSTMI(F)和CYPIAI(A)型基因的携带者作为参考组，考查各类GSTMI与CYPIAI基因型组合(Combination)携带者患肺癌的危险度。相对于参考组，GSTMI(D)与CYPIAI(A)型基因型组合携带者患肺癌的危险度升高1.338倍(95%Cl，0.537一3.319)，差异无显著性;GSTMI(F)与CYPIAI(B或C)基因型组合携带者患肺癌的危险度升高2.127倍(95%Cl，0.929一4.827);GSTMI(D)与CYPIAI(B)型基因型组合携带者患肺癌的危险度最高，升高6.456倍(95%Cl，2.740~15.210)，经统计学分析差别显著;GSTMI(F)与CYPIAI(B)基因型组合携带者患肺癌的危险度升高2.163倍(95%Cl，0.982一5.040)，无统计?更多还原

【Abstract】 Lung cancer (LC) is one of the six most common malignant diseases in the world . Lung cancer accounts for 19% of all cancer and 29% of all death. It is the commonest cause of cancer death to human in China. It has the highest mortality rate, too. Epidemiological study have shown that tobacco smoking is the most important etiological factor in the development of this cancer, and the risk is at least 20 times higher in long-term smoker compare nonsmokers. but only less than 20% persons risk to get the cancer. Obvoursely, there is a big deference to individuals’ susceptibility of this cancer. Recently, account of study shown there is a growing realization that the development of most cancers results from a complex interaction of both environmental and genetic factor. It is an important factor to lung cancer susceptibility of genetic polymorphism in the bioactivation of procarcinogens and detoxification of carcinogens. In the two fuction, CYPs and GSTs is the most important metabolize enzymes. The common polymorphism at the CYP1A1 gene nucleotide position 264 (T-C) and cause activity of the enzyme arise. Faction and deletion are the two polymorphisms for GSTM1 gene. The individual in deletion polymorphism produce a lot of enzyme without any normal function , and for this null allele are less efficient at conjugating and detoxifying specific substrate intermediates of carcinogens. The cancer risk were affected by polymorphic CYPs and GSTs together.We hypothesized that, with the mutation of CYP1A1 and GSTM1 gene, alterations of enzymes activities of CYP1A1 and GSTM1 caused by existing of genetic polymorphisms would raise the risk of lung carcinogenesis through disturbing bioactivation of procarcinogens and detoxification of carcinogens. And also may these polymorphisms contribute to the genetic basis of highlydistinguished and concordant geographical distribution of lung cancer in Henan Chinese people. To test our hypothesis, a retrospective case-control study was conducted to explore the associations, and then to provide informative evidences and useful methods for high-risk population screening, diagnosis and treatment. Materials and Methods:One hundred and three cases with lung cancer were recruited from the first and second affiliated hospital of Zhengzhou university, which were histopathologically confirmed from March to August in 2003. All cases were Chinese people from Henan areas and were investigated to exclude other simultaneous malignancies. One hundred and thirty-eight subjects with matched age and sex frequencies were randomly selected as control group from the same region in the field surveys between March and August in 2003.Genomic DNA was extracted from remnant liquid of blood clot or bronchoalveolar larage fluid (BALF) using protocols provided by Gentra Puregene DNA purification kit. Polymerase chain reaction (PCR) and PCR based restriction fragment length polymorphisms (PCR-RFLP) detection were applied to analyze genotypes of the polymorphisms. Retrospective case-control study was conducted and Fisher Exact x 2 test was adopted to check the accordance with Hardy-Weinberg equilibrium in the control group. For risk estimation, the risk was evaluated in terms of age-sex adjusted odds ratios (OR) and 95% confidence intervals (CD by unconditional logistic regression model. All of the statistical analyses were calculated by SPSS 10.0(USA) statistical software. (p<0.05 was regarded as significant) Results:1. For CYP1A1, the allele frequencies of ml were 28% and 43% in control and LC groups, respectively. For GSTM1, the allele frequencies of deletion were 44.2% and 61.2% in control and LC groups, respectively.2. The frequencies of CYP1A1 genotypes distribution were 52.3%, 39.1% and 8% for CYPlAlwl/wl ( A) , CYPlAlwl/ml (B) and CYP1A1 ml/ml( C ) in controls, respectively; For cases, the frequencies of CYP1 Al A, B, C, were 26.2%, 62.1% and 11.7% in individuals with LC, respectively. For GSTM1, frequencies of deletion were 44.2%. in controls, in cases with LC, fr更多还原