【作者】 都超群；

【导师】 张立玮； 王士杰；

【作者基本信息】 河北医科大学 ， 内科学， 2008， 硕士

【摘要】 目的:食管癌是世界上最常见恶性肿瘤之一,显著的地域性分布是其流行病学突出特征,高、低发区发病率和死亡率相差可达500倍。我国太行山南麓是世界上主要的食管癌高发区,近年来研究发现该地区贲门癌的发病率也处于较高水平,存在食管癌和贲门癌共同高发的现象。由于食管、贲门癌发病隐匿,就诊患者多为中晚期,术后5年生存率很低,因此筛选和建立与食管、贲门癌发生有关的基因多态作为鉴别易感个体的指标,将会为高发区食管、贲门癌的防治提供帮助。本研究旨在探讨促炎因子IL-8基因-251（A/T）位点单核苷酸多态性（Single nucleotide polymorphism,SNP）与太行山南麓食管癌高发区人群食管鳞状细胞癌（Esophageal squamous cell carcinoma,ESCC）和贲门腺癌（Gastric cardiac adenocarcinoma,GCA）发病风险的关系。方法:采用基于人群的病例-对照研究方法,对来自高发区320例食管鳞状细胞癌（Esophagealsquamous carcinoma, ESCC）、340例贲门腺癌（Gastric cardiac adenocarcinoma,GCA）和404例正常对照,均经内镜检查病理组织学确诊。幽门螺杆菌（Helicobacter pylori,H.pylori）感染情况通过活组织快速尿素酶试验（RUT）、病理切片HE染色和¹⁴C-尿素呼气试验(¹⁴C-UBT)检测,同时收集其个人史、疾病史、上消化道肿瘤家族史,并排除自身其它恶性肿瘤史。抽取2ml外周静脉血,经柠檬酸钠抗凝,提取DNA,应用聚合酶链反应-限制性片段长度多态性（Polymerase chain reaction-restriction fragment length polymorphism analysis, PCR-RFLP）方法检测研究对象IL-8各基因型的分布情况,任选显示不同基因型的标本进行DNA测序。比较各基因型频率的观察值与预期值并进行卡方检验行Hardy-Weinberg平衡分析。病例组与对照的基因型分布比较采用行×列表卡方检验。以非条件Logistic回归法计算经年龄、性别校正的相对风险度比值比（Odds ratio,OR）及其95%可信区间（Confidence interval, CI）。结果:1研究对象的一般特征:1.1 ESCC和GCA患者组中上消化道肿瘤（ Upper gastrointestinas cancers,UGIC）家族史阳性者的比例（分别为44.7%和48.6%）显著高于健康对照组（32.6%）（χ2=4.707和17.785,P<0.05）。因而,UGIC家族史阳性可显著增加ESCC和GCA的发病风险,经性别、年龄等调整后的OR值分别为1.721和3.679（95%CI=1.251-2.367和2.178-6.216）。1.2 ESCC和GCA患者组的吸烟者比例（51.3%和47.1%）与对照组（38.9%）相比均有显著性差异（χ²值为10.383和4.467, P值分别为0.001和0.035）,经年龄、性别、家族史和H. pylori感染（贲门癌）校正后的OR值分别为1.684和1.211（95%CI=1.215-2.336和0.736-1.992）,由此可见在剔除了其它影响因素后吸烟是食管癌发病的危险因素而与贲门癌的发病无关。1.3 GCA患者组中H. pylori感染阳性率（65.7%）明显高于对照组（35.1%）（χ²=4.896,P=0.001）,经年龄、性别、吸烟状况和家族史校正后的OR值为5.276（95%CI=3.230-8.618）。2健康对照组、ESCC组和GCA组中的IL-8多态位点的基因型分布均符合Hardy-Weinberg平衡（P>0.05）,三组IL-8-251 AA、AT、TT基因型频率分别为18.3%、49.5%、32.2%;15.6%、23.1%、29.7%和24.7%、49.7%、25.6%。IL-8-251A/T SNPs基因型和等位基因型总体分布在ESCC患者组和健康对照组之间均无显著性差异（P>0.05）。IL-8-251A/T SNP的A等位基因频率和AA基因型频率在GCA患者组（分别为49.6%和24.7%）均显著高于健康对照组（43.1%和18.3%）（χ2=6.26和6.299,P=0.012和0.043）,与TT基因型相比,携带AA基因可显著增加GCA的发病风险（OR=2.014,95%CI =1.017-3.990）。3根据个体吸烟状况进行分层分析发现,在吸烟组及非吸烟组均未发现IL-8-251A/T SNPs影响ESCC和GCA的发病风险。4根据有无UGIC家族史分层分析发现,与IL-8-251A/T的TT基因型相比,携带AA基因型可显著增加UGIC家族史阳性的个体ESCC和GCA的发病风险,经性别、年龄校正后的OR值分别为2.378（95%CI=1.075-5.258）和14.895（95%CI=2.889-76.516）。而IL-8-251A/T SNPs并不影响UGIC家族史阴性个体的ESCC和GCA的发病风险。5根据H. pylori感染状况分层分析发现,在H. pylori感染阳性组中,GCA组AA基因型频率明显高于健康对照组（P=0.017）,与携带TT基因型个体相比,GCA的发病风险显著升高,经性别、年龄、吸烟、家族史校正后的OR值为3.520（95%CI=1.249-9.918）,而在H. pylori感染阴性组中三种基因型分布频率未见统计学差异。结论:1.携带IL-8-251AA基因型个体显著增加贲门癌发病风险,尚未发现IL-8-251位点单核苷酸多态性与高发区人群ESCC的易感性有关。2.上消化道癌家族史阳性是食管、贲门癌的易感因素,家族史阳性携带IL-8-251AA基因型的个体贲门癌的发病风险显著增高,虽未提示基因型与食管癌患者发病有关,但有遗传家族史背景且携带AA基因型个体易患食管癌。3. H.pylori感染明显增加贲门癌的发病风险,H. pylori感染阳性携带IL-8-251AA基因型的个体显著增加贲门癌的发病风险。4.吸烟是食管癌发病的危险因素,与贲门癌的发病风险不明显,尚未发现IL-8-251AA基因型增加吸烟及非吸烟组食管、贲门癌的发病风险。更多还原

【Abstract】 Objective: Esophageal cancer is one of the most common malignant tumors in the world. A very remarkable feature of the cancer is the highly centralized occurrence in the high risk regions, with the difference in incidence and mortality rates as large as 500 times exist between the high and low risk areas. The South Taihang mountain region of our country has been well recognized as the highest incidence area for esophageal cancer in the world. Recently it is know that this area not only bears high risk for esophageal cancer, but also for cardiac cancer. However, early diagnosis of the cancer is hard to achieve because patients in the early stage have no obvious symptoms, and majority of patients treated in tumor hospital are in the late stage, so the five year survival rates after operation were low. So determination of individuals with high risk and detection of esophageal cancer and gastric cardiac cancer at earlier stages probably gives the best chance to improve prognosis.The aim of this study is to investigate whether the -251A/T polymorphism of the IL-8 promoter was associated with susceptibility to esophageal squamous cell carcinoma (ESCC) and gastric cardiac adenocarcinoma (GCA) in south of Taihang mountain, a high incidence area of China.Methods: This population-based case-control study included 320 cases esophageal squamous carcinoma, 340 cases gastric cardiac adenocarcinoma and 404 cases healthy controls ,came from high incidence region of Taihang mountain. The total patients were diagnosed by histopathology, and detected the infection of H.pylori in GCA by RUT ,histopathology and 14C-urea breath test. In the same period, we collected the disease history, personal history, family history,and so on. Genomic DNA was extracted by tiangen kit. IL-8 polymorphisms were analyzed by polymerase chain reaction(PCR)-restriction fragment length polymorphis -m (RFLP). Random sampling of DNA sequencing analysis was used to confirm the results of IL-8 genotyping. Hardy-Weinberg analysis was performed by comparing the observed and expected genotype frequencies in study groups using Chi-square test. Comparison of the IL-8 genotype and allelotype distribution in the study groups was performed by means of two-sided contingency tables using Chi-square test. The odds ratio (OR) and 95% confidence interval (CI) were calculated using an unconditional logistic regression model and adjusted by age and gender accordingly.Results: 1 Demographic characteristics of ESCC,GCA patients and healthy controls:1.1 The frequency of positive family history of upper gastrointestinal cancer (UGIC) in ESCC (44.7%) and GCA (48.6%) patients was significantly higher than that in healthy controls (32.6%) (χ~2= 4.707 and17.785, P <0.05),so family history of UGIC significantly enhanced the risk of developing ESCC and GCA[the age, gender, smoking status, and infection of H.pylori (GCA) adjusted odds ratio(OR)=1.721, 95% confident interval(CI)= 1.251-2.367; OR=3.679, 95%CI = 2.178-6.216].1.2 The proportion of smokers in ESCC and GCA patients(51.3% and 47.1% respectively) were significantly different from that in healthy controls (38.9%)(χ2=10.383 and 4.467, P =0.001 and 0.035, respectively),[the adjusted odds ratio(OR)=1.684,95% confident interval(CI)=1.215-2.336; OR=1.211, 95%CI= 0.736-1.992],so smoking significantly enhanced the risk of developing ESCC,but not GCA.1.3 Infection of H.pylori in GCA patients(65.7%)was significantly more common than that in healthy controls(35.1%)(χ~2=4.896, P =0.001),so infection of H.pylori was a risk factor of developing GCA[the adjusted odds ratio(OR)=5.276,95%CI= 3.230-8.618].2 The distribution of the IL-8 polymorphisms among ESCC,GCA patients and healthy conctrols did not significantly deviate from those expected by Hardy-Weinberg equilibrium(P >0.05).The frequency of the IL-8-251 AA、AT、TT in healthy controls were 18.3%、49.5%、32.2%,in ESCC patients were 15.6%、23.1%、29.7% and in GCA patients were 24.7%、 49.7%、25.6%。The allelotype and genotype distribution of the IL-8-251A/T SNPs in the overall ESCC patients were not significantly different from that in healthy controls(P >0.05).However, the frequency of IL-8-251 A allelotype and AA genotype distribution in GCA patients(49.6% and 24.7%,respectively)was significantly higher than that in healthy controls(43.1% and 18.3%)(χ~2=6.26 and 6.299, P =0.012 and 0.043, respectively).Compared with individuals with the TT genotype, individuals with the AA genotype had significantly higher risk to develop GCA[the adjusted OR=2.014,95%CI=1.017-3.990].3 Stratification analysis by smoking status found that the IL-8-251A/T polymorphisms didn’t increase the risk of developing ESCC and GCA in all subgroups.4 When stratified by family history of UGIC, a significant association of the IL-8-251 AA genotype with increased risk of ESCC and GCA were observed among individuals with positive family history, compared with the TT genotype[the adjusted OR=2.378 and 14.895,95%CI=1.075-5.258 and 2.889-76.516, respectively],while IL-8-251A/T polymorphisms didn’t increase the risk of developing ESCC and GCA among the subjects without family history of UGIC [the adjusted OR=0.497 and 1.120,95%CI=0.243-1.018 and 0.452-2.779, respectively].5 When stratified by infection of H.pylori, the frequency of AA genotype in the group of positive H.pylori infection was significantly higher than that in negative group(P =0.017), AA genotype significantly increased susceptibility to GCA among individuals with H.pylori infection[the adjusted OR=3.520, 95%CI=1.249-9.918].Conclusions: 1 IL-8-251AA genotype significantly increased the risk of developing GCA, while IL-8-251 polymorphisms might not be independent factors to predict the risk of the development of ESCC in South Taihang mountain.2 Family history of upper gastrointestinal cancer(UGIC) significantly enhanced the risk of developing ESCC and GCA, stratification analysis showed that IL-8-251AA genotype significantly enhanced susceptibilities to ESCC and GCA among the individuals with UGIC history, IL-8-251 polymorphisms might not be independent factors to predict the risk of the development of ESCC, notwithstanding.3 H.pylori infection increased the risk of developing GCA, IL-8-251AA genotype significantly enhanced susceptibilities to GCA among the individuals with H.pylori infection .4 Smoking significantly enhanced the risk of developing ESCC, while there was no relationship between smoking and GCA, no evidence was found that IL-8-251 AA genotype enhanced susceptibilities to ESCC and GCA among smokers or non-smokers.更多还原