【作者】 晏冬；

【导师】 王喜艳；

【作者基本信息】 新疆医科大学 ， 外科学， 2010， 博士

【摘要】 目的：探讨人类X-射线修复交叉互补基因(XRCC1)、着色性干皮病基因D(XPD)单核苷酸多态性及其单体型与胰腺癌发病风险的相关性。方法：病例组为111例新疆汉族、维吾尔族胰腺癌患者；对照组为111例排除肿瘤性疾病的同期住院患者,对照按年龄(±5岁)、性别、民族因素与病例进行频数匹配。采用病例—对照研究方法,用SNaPshot SNP分型技术对XRCC1基因rs25487(SNP1)、rs3213403(SNP2)、rs731420(SNP3)、rs3213282(SNP4)、rs12611088(SNP5)、rs1001581(SNP6)和rs1799782(SNP7)位点多态基因型进行检测,同时进行单体型与胰腺癌的关联研究。针对临床胰腺癌发病相关因素,采用单因素及多因素Logistic回归分析,筛选影响胰腺癌发病的独立危险因素,并进行XRCC1基因与主要发病危险因素间交互作用的研究。采用同样技术对XPD基因rs13181(SNP1)、rs3916874(SNP2)、rs238415(SNP3)、rs50872(SNP4)、rs50871(SNP5)和rs238406(SNP6)位点多态基因型进行检测,同时进行单核苷酸多态性与胰腺癌遗传易感性的关联分析。结果：第一部分：采用单因素及多因素Logistic回归模型,分析影响胰腺癌发病的11项相关因素。单因素分析显示吸烟、饮酒是胰腺癌发病的可能危险因素；多因素分析显示,吸烟(P=0.022,OR=1.946,95%CI:1.099-3.445)是胰腺癌发病的独立危险因素。男性每日吸烟≥10支胰腺癌发病风险高于不吸烟患者(P=0.009,OR=1.610,95%CI：1.129～2.296)；女性生育1-2胎、3-4胎、≥5胎并未增加胰腺癌发病风险(P>0.05)；病例组患者1年内糖尿病发病率高于对照组,差异有统计学意义(P=0.044)。第二部分：(1)XRCC1基因SNP1位点GA、AA基因型和A等位基因频率在病例组均高于对照组,差异有统计学意义,P值分别为0.014和0.023。非条件logistic回归分析表明,在调整了年龄、性别、民族因素后,以GG基因型作为参照,携带GA基因型的个体较GG基因型,胰腺癌患病风险增加(P=0.007, adjusted OR=2.510,95%CI:1.309～4.889);携带AA基因型(P=0.021,adjusted OR=2.468,95% CI：1.110-5.511)、GA+AA基因型(P=0.005,adjustedOR=2.508,95% CI：1.334-4.732)的个体胰腺癌患病风险亦增加,差异有统计学意义。(2)SNP7位点CT、TT基因型和T等位基因频率在病例组均高于对照组,差异有统计学意义,P值分别为0.028和0.011。非条件logistic回归分析表明,在调整了年龄、性别、民族因素后,以CC基因型作为参照,携带CT基因型的个体较CC基因型,胰腺癌患病风险增加(P=0.015,adjusted OR=2.150,95% CI：1.191-3.866)；携带CT+TT基因型的个体胰腺癌患病风险亦增加(P=0.010,adjustedOR=2.149,95% CI：1.220-3.791),差异均有统计学意义。携带TT基因型的个体,并未增加胰腺癌的患病风险(P=0.298,adjusted OR=2.160,95% CI：0.479～9.501)。(3)以单体型Hap1-AACCTAG作为参考基线,Hap4-AGCTTGG与胰腺癌发病风险之间呈正相关(P=0.61,OR=1.19,95% CI:0.62-2.28),与Hap1-AACCTAG比较,Hap4-AGCTTGG单体型患胰腺癌的风险增加了0.19倍,差异无统计学意义。(4)在每天吸烟10支以上的个体中,比较GG基因型,携带SNP1位点至少一个突变等位基因(GA+AA)的个体发生胰腺癌的风险增加(P=0.005,adjustedOR=5.480,95% CI：1.563～19.426),差异有统计学意义；比较CC基因型,携带SNP7位点至少一个突变等位基因(CT+TT)的个体发生胰腺癌的风险亦增加(P=0.035,adjusted OR=4.012,95%CI:1.041-15.160),差异有统计学意义。第三部分：(1)XPD/ERCC2基因SNP1位点AC、CC基因型和C等位基因频率在病例组均高于对照组,差异有统计学意义,P值分别为0.023和0.003。非条件logistic回归分析表明,在调整了年龄、性别、民族因素后,以AA基因型作为参照,携带AC基因型的个体较AA基因型,胰腺癌患病风险增加了1.035倍(P=0.030,adjusted OR=2.035,95% CI：1.121～3.885)；携带AC+CC基因型的个体胰腺癌患病风险亦增加了1.029倍(P=0.007,adjusted OR=2.029,95% CI：1.255～3.712),二者差异均有统计学意义。携带CC基因型的个体胰腺癌患病风险亦增加(P=0.051,adjusted OR=2.251,95% CI.1.122～5.017),但差异无统计学意义。(2)XPD/ERCC2基因SNP1(rs13181)位点多态性与吸烟存在交互作用,在每天吸烟10支以上的个体中,比较AA基因型,携带SNP1位点至少一个突变等位基因(AC+CC)的个体发生胰腺癌的风险增加(P=0.033,OR=4.243,95% CI：1.123～16.857),差异有统计学意义。结论：吸烟是影响胰腺癌发病的独立危险因素。核苷酸切除修复基因XPD Lys751Gln、碱基切除修复基因XRCC1 Arg399Gln Arg194Trp突变均可导致DNA修复能力的下降,从而增加个体对胰腺癌的易感性,提示DNA修复基因XRCC1、XPD多态性与胰腺癌发生相关,有可能是决定胰腺癌个体遗传易感性的重要因素。更多还原

【Abstract】 Objective:To investigate the correlation of the single nucleotide polymorphisms and haplotypes of XRCC1 and XPD related to the risk of pancreatic cancer. Methods:A hospital-based case-control design was applied in this study. In brief, a total of 111 patients diagnosed with pancreatic cancer by histopathological confirmation and imaging with long-term follow-up. Cancer-free control subjects consisted of patients from the first affiliated hospital of Xinjiang medical university at the same hospital during the same study period. All the control subjects were frequency-matched to the cases on age (±5 years), gender and nationality. The detailed information on each patient was investigated including the family history of cancer, the smoking and drinking history, demographic information and the history of digestive operation and so on. The genomic DNA was extracted from all peripheral blood samples. Based on genotype data from the international HapMap project, the tagging single nucleotide polymorphisms (tSNPs) initially were selected using haploview 4.0 software. And pairwise linkage disequilibrium values D’ and r2 were calculated in the control population using the Maximation likelihood method. Haplotype frequencies were estimated using Phase 2.0 software. The locus of XRCC1 gene including rs25487 (SNP1), rs3213403 (SNP2), rs731420 (SNP3), rs3213282 (SNP4), rs12611088 (SNP5), rs1001581 (SNP6), s1799782 (SNP7) were genotyped by snapshot method and the haplotype distribution was estimated. Aimed at the factors related to pancreatic cancer, univariate and multivariate logistic regression were performed to screen the independent risk factors to pancreatic cancer and interaction between XRCC1 gene and main risk factors was studied. The same way was used in testing the locus of XPD gene including rs13181 (SNP1), rs3916874 (SNP2), rs238415 (SNP3), rs50872 (SNP4), rs50871 (SNP5), rs238406 (SNP6), while the relationship of single nucleotide polymorphisms with genetic susceptibility to pancreatic cancer were investigated. Results:Section one:Univariate and multivariate analysis were performed to examine factors affecting the incidence of pancreatic cancer by Logistic regression model. Eleven factors were included in this study. Univariate analysis showed that smoking and drinking were all significant related factors to pancreatic cancer. Multivariate analysis showed smoking (P=0.022, OR=1.946,95%CI:1.099～3.445) was independent risk factor for pancreatic cancer. Risk of pancreatic cancer was higher in male patients with more than 10 cigarettes daily than in non-smoking patients (P=0.009, OR=1.610,95%CI:1.129～2.296). Female patients with number of births of 1～2,3～4 and more than 5 did not increase the risk of pancreatic cancer (P> 0.05). Morbility of diabetes mellitus within 1 year in case group was higher than in control group (P=0.044). Section two:seven common SNPs of XRCCl genes were chosen to be tagging SNPs. All polymorphisms were in Hardy-weinberg equilibrium both in control and in case groups. The distributions of GA, AA genotypes and A allele of XRCCl SNP1 (SNP rs25487) in case patients were higher than in control subjects and P equals to 0.014,0.023. In the unconditional logistic regression analysis, after adjustment for age, gender and nationality, the SNP rs25487 was significantly associated with an increased risk of pancreatic cancer (GA versus GG:P=0.007, OR=2.510,95% CI:1.309～4.889; AA versus GG:P=0.021, OR=2.468,95% CI:1.110～5.511; GA+AA versus GG:P=0.005,OR=2.508,95% CI: 1.334～4.732). The distributions of CT, TT genotypes and T allele of SNP7 (rs1799782) in case patients were higher than in control subjects, and P equaled to 0.028,0.011 respectively. In the unconditional logistic regression analysis, after adjustment for age, gender and nationality, the SNP rs1799782 was significantly associated with an increased risk of pancreatic cancer (CT versus CC:P=0.015, OR=2.150,95% CI:1.191～3.866; CT+TT versus CC:P=0.010, OR=2.149,95% CI:1.220～3.791), the difference was statistically significant. Individuals carrying TT genotype did not increase risk of pancreatic cancer compared with the wild genotype (TT versus CC:P=0.298, OR=2.160, 95% CI:0.479～9.501).Compared with the haplotype Hapl-AACCTAG, the relationship between Hap4-AGCTTGG and the incidence of pancreatic cancer was positive (P=0.61, OR=1.19,95% CI:0.62～2.28). The haplotype analysis revealed that individuals with Hap4-AGCTTGG have a 0.19-fold excess risk of pancreatic cancer compared with individuals with the Hapl-AACCTAG haplotype, there was no statistically significant difference. Interaction between SNP1 locus and smoking over 10 cigarette per day revealed a increased risk of pancreatic cancer (GA+AA versus GG:P=0.005, adjusted OR=5.480,95% CI:1.563-19.426) as well as SNP7 locus (CT+TT versus CC:P=0.035, adjusted OR=4.012,95% CI:1.041-15.160), the difference was statistically significant. Section three:The distributions of AC, CC genotypes and C allele of XPD/ERCC2 tSNPs(SNP1 rs 13181 A35931C) in case patients were higher than in control subjects and P equals to 0.023,0.003. There were no statistically significant differences between cases and controls in genotype distribution of SNP2, SNP3, SNP4, SNP5 and SNP6 locus. In the unconditional logistic regression analysis, after adjustment for age, gender and nationality, individuals carrying AC genotype had a 1.035-fold increased risk of pancreatic cancer compared with the wild genotype (AC versus AA:P=0.030, OR=2.035, 95% CI:1.121-3.885), individuals carrying AC+CC genotype had a 1.029-fold increased risk of pancreatic cancer compared with the wild genotype (AC+CC versus AA: P=0.007, OR=2.029,95% CI:1.255-3.712), the difference was statistically significant. Those carrying CC genotype also had a increased risk (P=0.051, OR=2.251,95% CI: 1.122-5.017), there were no statistically significant differences. Interaction between SNP1 locus of XPD gene and smoking more than 10 cigarette per day revealed a increased risk of pancreatic cancer (AC+CC versus AA:P=0.033, OR=4.243,95% CI: 1.123-16.857).Conclusion:Smoking is significant independent risk factor for pancreatic cancer. Our study revealed that the polymorphisms of Arg399Gln and Arg194Trp in XRCCl and Lys751Gln in XPD might decrease the DNA repair ability and increase the susceptibility to pancreatic cancer. DNA repair gene XRCCl and XPD might be an important determinative factor for susceptibility to pancreatic cancer.更多还原