DNA修复基因XPD751单核苷酸多态性与 结直肠癌化疗疗效的相关性

 目的 研究结直肠癌患者DNA修复基因XPD751单核苷酸多态性与铂类药物化疗敏感度的关系。方法 经病理学确诊的晚期结直肠癌患者98例,均行草酸铂联合5-氟尿嘧啶的方案（FOLFOX）治疗。所有病例化疗前抽取静脉血并提取DNA,采用多聚酶链反应 限制性片段长度多态性分析（PCR RFLP）技术检测XPD751单核苷酸多态性。比较不同基因型与化疗疗效的关系。结果 （1）XPD751 Lys/Lys、Lys/Gln和Gln/Gln基因型频度分别为76（77.55%）、17（17.35%）和5（5.10%）。（2）XPD751 Lys/Lys、Lys/Gln 和Gln/Gln基因型有效率分别为50.00%、29.41%和20%,比较Lys/Lys、Lys/Gln的有效率,两者之间的差异有统计学意义（χ²=4.04,P<0.05）。在调整性别、年龄及不同转移部位的影响后,XPD751 Lys/Gln基因型患者化疗失败的可能性是Lys/Lys 基因型患者的3.8倍,OR=3.8,95%CI为0.985~14.698。结论 DNA修复基因XPD751单核苷酸多态性与结直肠癌对FOLFOX方案化疗敏感度相关,检测XPD751单核苷酸多态性可能成为预测结直肠癌患者接受FOLFOX方案化疗敏感度的指标。     

结直肠癌基因XPD751和XPD312单核苷酸多态性与FOLFOX方案疗效相关性分析

目的探讨DNA修复基因XPD751和XPD312单核苷酸多态性与FOLFOX方案治疗中国晚期结直肠癌患者疗效的相关性;探讨两种基因单核苷酸多态性在晚期结直肠癌患者预后评估中的预测价值。方法收集2008-01-01-2013-12-31我院经病理学确诊并接受FOLFOX方案治疗的晚期结直肠癌76例患者,采集患者化疗前外周静脉血,经DNA提取后采用限制性片段长度多态性聚合酶链反应（RFLP-PCR）技术检测XPD751和XPD312的单核苷酸多态性,比较不同基因型与化疗疗效及预后的相关性。结果 XPD751野生型和突变型的分布频度分别为76.3%和23.7%,XPD312野生型和突变型的分布频度分别为55.3%和44.7%;XPD751野生型组和突变型组的疾病控制率（DCR）分别为79.3%和77.7%,XPD312分别为64.2%和79.4%,XPD751野生型患者化疗有效率优于突变型患者,χ^2=5.141,P=0.007;Logistic回归分析显示,携带XPD751野生型患者接受FOLFOX方案化疗的敏感性是携带突变型患者的3.5倍,OR=3.500,P=0.015。XPD312野生型组和突变型组化疗疗效差异无统计学意义,χ^2=2.456,P=0.483。XPD751野生型和突变型的中位无进展生存期（PFS）分别为9.96和7.8个月,XPD312分别为9.88和8.41个月。XPD751两类基因型的中位PFS差异有统计学意义,χ^2=11.769,P=0.001;XPD312两类基因型的中位PFS差异无统计学意义,χ^2=1.479,P〉0.05。同时携带XPD751野生型和XPD312野生型的PFS为12.95个月,同时携带XPD751野生型和XPD312突变型的PFS为8.36个月,同时携带XPD751突变型和XPD312野生型的PFS为7.8个月,同时携带XPD751突变型和XPD312突变型的PFS为7.14个月,组间差异有统计学意义,χ^2=12.722,P=0.005。Cox回归分析性别、年龄、肿瘤转移部位及上述四类基因分型与PFS的相关性显示,只有基因分型与PFS相关,P〈0.001,RR=1.445;分析上述四类基因分型,只有同时携带XPD751野生型和XPD312野生型的基因分型与PFS相关,P=0.006,RR=0.357。结论DNA修复基因XPD751单     

XRCC1 R399Q基因多态性与结直肠癌易感性的Meta分析

目的探讨X—rayrepair cross—complementing group1（XRCC1）RB99Q基因多态性与结直肠癌易感性的关系。方法通过计算机检索和手工检索,收集有关XRCC1 R399Q基因多态性与结直肠癌易感性关系的文献,筛选出符合条件的文献,应用Meta分析软件对各项研究进行异质性检验,计算合并OR值及其95％可信区间,并行敏感性分析和发表偏倚的评估。结果国内外共有21篇文献纳入研究（结直肠癌组6229例;对照组10692例）。Meta分析结果显示：XRCC1 R399Q基因多态性在整个人群中与结直肠癌无明显的关联性（OR QQvs、RR=1．10,95％CI=0．90～1．35;OR QQ/RQvs.RR=1．02,95％CI=0．90～1．16;OR QQvs.RR/RQ=1．12,95％CI=0．95～1．33）。通过种族的分层分析发现XRCC1 R399Q基因多态性与结直肠癌易感性在亚洲人群和欧洲人群中无差异。结论XRCC1 R399Q基因多态性与结直肠癌间不存在明显的易感性。     

DNA双链断裂修复基因XRCC4多态性与肺癌易感性的关系

目的:探讨DNA双链断裂修复基因X-射线修复交叉互补4(X-ray repair cross-complementing 4, XRCC4)基因单核甘酸多态性(single nucleotide polymorphism, SNP)与肺癌发生风险的关系.方法:采用病例-对照研究的方法,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, PCR-RFLP)技术和TaqMan探针基因分型技术对781例肺癌患者和781健康志愿者(作为对照)进行XRCC4 rs6869366、rs3734091和rs1056503多态性的检测;结合PCR和定点突变技术,分别构建含有XRCC4基因启动子rs6869366位点不同等位基因的重组质粒,以双荧光素酶报告系统检测SNP位点碱基突变对启动子活性的影响.结果:XRCC4 rs6869366位点携带G等位基因的基因型(T/G+G/G)可显著增加肺癌的患病风险[比值比(odds ratio, OR)=1.607, 95%可信区间(confidence interval,CI): 1.138~2.270];rs6869366与rs3734091存在连锁不平衡,携带由其构建的单体型GC或单体型对TC/GC者患肺癌的风险增加(OR=1.993,95%CI:1.194~3.329;OR=2.013,95%CI:1.174~3.452);含rs6869366不同等位基因的启动子转录活性差异无统计学意义.结论:XRCC4 rs6869366位点多态性与肺癌的易感性有关,其影响机制还需进一步研究.     

XRCC1 Arg399Gln位点多态性和结直肠癌易感性关系的Meta分析

[目的]探讨X射线交叉互补修复基因1（X-ray repair cross-complementing group1,XRCC1）的399位点（Arg399Gln）多态性与结直肠癌（CRC）易感性的关系。[方法]检索中国生物医学数据库（CBM）、PubMed、Springer等数据库,获取有关XRCC1Arg399Gln多态性同结直肠癌易感性关系的病例对照研究并进行Meta分析,以病例组及对照组XRCC1Arg399Gln等位基因分布的比值比（OR）为效应指标,应用Meta分析软件Review Manager（version5.0.10）对各研究原始数据进行统计处理及异质性检验,计算合并OR值及其95%可信区间（95%CI）。[结果]纳入11项病例对照研究,共2287例结直肠癌患者和3485例对照,Meta分析结果显示,Gln/Gln vs.Arg/Arg OR=1.12,95%CI为0.76～1.65,Z=0.58,POR=0.56;Gln/Gln＋Arg/Gln vs.Arg/Arg OR=1.11,95%CI为0.85～1.44,Z=0.78,POR=0.43;Gln/Glnvs.Arg/Arg＋Arg/Gln OR=1.07,95%CI为0.79～1.46,Z=0.43,POR=0.67;Arg/Gln vs.Arg/Arg OR=1.14,95%CI为0.88～1.48,Z=1.02,POR=0.31。[结论]XRCC1Arg399Gln多态性与结直肠癌易感性之间无显著相关性。     

DNA修复基因XRCC1基因多态性与乳腺癌临床病理参数的相关性

目的 :研究XRCC1基因Arg194Trp和Arg399Gln多态性与中国女性乳腺癌临床病理参数的关系,探讨其在乳腺癌预后中的潜在意义。 方法 :采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法,对250例原发性乳腺癌患者进行XRCC1基因Arg194Trp、Arg399Gln多态性分析,用Pearsonχ²检验分析基因型与临床病理特征的关系。 结果 :XRCC1基因Arg194Trp和Arg399Gln多态性与乳腺癌患者的月经状态、肿瘤大小、腋窝淋巴结转移、TNM分期、雌激素受体均无显著相关性(P>0.05)。但该多态位点与乳腺癌患者的孕激素受体(PR)状态和C-erbB2蛋白表达显著相关。携带194纯合突变型的患者PR阴性率(81.0%)显著高于携带194野生型和杂合型患者(55.4%),(P=0.034);携带399纯合突变型的患者C-erbB2蛋白表达阳性率(61.1%)显著高于携带399野生型和杂合型的患者(29.3%),(P=0.006)。 结论 :PR阴性和(或)C-erbB2高表达的乳腺癌患者常提示预后不良。XRCC1基因多态性与PR阴性或C-erbB2高表达显著相关,提示携带XRCC1纯合突变(194或399)乳腺癌患者可能预后不良。     

DNA修复基因XRCC1多态性与肺癌易感性的关系

目的:研究碱基切除修复基因XRCC1多态性与肺癌易感性的关系。方法:采用病例-对照研究,收集太原市原发性肺癌患者111例为病例组,同时随机抽取210名健康居民作为对照组,并进行流行病学调查。应用PCR-RFLP方法分析由内切酶MspI识别XRCC1基因Arg399Gln位点的多态性,比较不同基因型与肺癌易感性的关系,以及基因多态性与吸烟之间对肺癌易感性的交互作用。结果:XRCC1密码子399杂合基因型Arg/Gln可能对鳞癌有较弱的保护效应,并可能降低吸烟者患肺癌的危险性。而纯合突变基因型Gln/Gln与和吸烟的存在协同作用可显著提高肺癌的危险度。结论:碱基切除修复基因XRCC1密码子399的多态性可能会对肺癌易感性产生影响,并可能与吸烟量之间存在一定的协同作用。     

代谢酶基因多态性与结直肠癌易感性

外源致癌物进入机体后，需经一系列酶系统代谢活化或转化，成为终致癌物或毒性降低后排出体外。代谢酶的基因多态性使酶的活性有差异，可能为结直肠癌易感性的重要机制。现综述Ⅱ相代谢酶基因多态性与结直肠癌易感性的关系。     

DNA修复基因XRCC1多态性与肺癌易感性研究进展

X线修复交叉互补基因1（XRCC1）是一种重要的DNA修复基因，参与DNA单链断裂和碱基损伤修复，其编码的蛋白质在碱基修复过程中是不可缺少的。该基因的多态性会导致相应的氨基酸改变，从而影响DNA修复，可能引起肿瘤的易感性。XRCC1基因多态性与吸烟交互作用对肺癌易感性的关系仍然存在争论，其相关性需进一步深入研究。     

DNA切除修复基因单核苷酸多态性与食管癌易感性的研究进展

食管癌是我国最常见的恶性肿瘤之一,目前普遍认为食管癌是多因素作用、多基因参与,多阶段发展的疾病,但其发生和发展的确切机制仍未阐明。研究发现食管癌具有很明显的地理分布差异,因而推测发病与环境有较大关系;但同样暴露于相似环境因素的人群中却只有少数人发生食管癌,提示个人的遗传因素可能有重要作用。有学对福建安溪县食管癌家族聚集性进行研究,发现具有明显家族聚集倾向,然而迄今尚无直接证据表明确实存在高度外显的食管癌易感基因。     

Genetic polymorphisms in DNA repair genes XPC,XPD, and XRCC4, and susceptibility to Helicobacter pylori infection‐related gastric antrum adenocarcinoma in Guangxi population,China

Genetic polymorphisms in DNA repair genes may influence individual variation in DNA repair capacity, which may be associated with risk of gastric antrum adenocarcinoma (GAA) related to Helicobacter pylori infection. This study, including 361 GAAs and 616 controls without any evidence of tumors, was designed to evaluate the association between the polymorphisms of DNA repair genes XPC Ala499Val (RS#2228000) and Lys939Gln (RS#2228001), XPD Lys751Gln (RS#13181), and XRCC4 Ala247Ser (RS#3734091) and Ser298Asn (RS#1805377), and GAA risk for Guangxi population by means of TaqMan‐PCR analysis. Increased risks of GAA were found for individuals with H. pylori positive [odds ratio (OR), 2.48; 95% confidence interval (CI), 1.84–3.33] or cagA positive (OR, 7.34; 95% CI, 5.46–9.87). No differences were observed among the studied groups with regard to the genotype distribution of XPC codons 499 and 939 and of XRCC4 codon 247; but XPD codon 751 genotypes with Gln [ORs (95% CI) were 2.67 (1.98–3.58) and 3.97 (2.64–5.99) for Lys/Gln and Gln/Gln, respectively] and XRCC4 codon 298 genotypes with Asn [ORs (95% CI) were 3.01 (2.21–4.10) and 4.78 (3.24–7.05) for Ser/Asn and Asn/Asn, respectively] increased the risk of GAA. Interestingly, there was an interactive effect between the risk genotypes of these two genes and cagA‐positive status in the GAA risk (OR_interact = 2.05 and 2.08, respectively). However, we did not find the gene–H. pylori‐status interaction effects on the risk of GAA (P_interact > 0.05). The results suggested that the polymorphisms of XPD codon 751 and XRCC4 codon 298 are associated with an increased risk of developing H. pylori‐related GAA among Guangxi population. © 2010 Wiley‐Liss, Inc.     

Genetic polymorphisms of DNA repair genes XRCC1 and XRCC3 and risk of colorectal cancer in Chinese population

Aim: The distribution of DNA repair gene XRCC1 and XRCC3 genotypes was used to assess the potential influence of genetic polymorphisms on risk of colorectal cancer, and interactions with other factors. Methods: a 1:2 matched case-control study was conducted with 485 cases and 970 controls. XRCC1 and XRCC2 genotype polymorphisms were based upon duplex polymerase-chain-reaction with the confronting-two-pairprimer (PCR-CTPP) method. Results:The XRCC1 399Cln allele polymorphism was found to be associated with an increased colorectal cancer risk, while an non-significant inversely association was noted for XRCC3 241Thr/Thr genotype. We also found that individuals with the XRCC1 399 Gln and XRCC3 241Met alleles had an elevated risk, while XRCC3241Thr/Thr was proctective. Conclusion: This study is the first to provide evidence of importance of XRCC1 and XRCC3 gene polymorphisms for risk of colorectal cancer in the Chinese population.     

Polymorphisms of DNA repair genes XRCC1 and XPD and their associations with risk of esophageal squamous cell carcinoma in a Chinese population

Esophageal squamous cell carcinoma (ESCC), which is prevalent in China, is believed to be induced by environmental carcinogens. Accumulating evidence has shown that individual variation in DNA repair capacity resulting from genetic polymorphism influences risk of environmental carcinogenesis. We therefore investigated the associations between genetic polymorphisms in the DNA repair genes XRCC1 (Arg194Trp and Arg399Gln) and XPD (Asp312Asn and Lys751Gln) and risk of ESCC in an at-risk Chinese population. Genotypes were determined by a PCR-based approach in 433 patients with ESCC and 524 frequency-matched normal controls. We found that individuals with Trp/Trp genotype at XRCC1 Arg194Trp site had a 2-fold increased risk of this disease compared to Arg/Arg genotype (adjusted OR = 1.98; 95% CI 1.26-3.12). Furthermore, when compared to Arg/Arg and Arg/Trp genotype combined, homozygote for Trp/Trp genotype significantly increased the risk of developing ESCC, with the adjusted OR being 2.07 (95% CI 1.34-3.20). However, the XRCC1 Arg399Gln polymorphism was not significantly associated with risk of ESCC, with the adjusted OR being 0.87 (95% CI 0.55-1.37). Neither Asp312Asn nor Lys751Gln polymorphisms in the XPD gene influenced risk of ESCC in our study. These findings suggest that DNA repair gene XRCC1 but not XPD might play a role in esophageal carcinogenesis and might represent a genetic determinant in the development of the cancer.     

Polymorphisms in DNA repair genes XPD and XRCC1 and p53 mutations in lung carcinomas of never-smokers

The etiology of lung cancer in population with little or no tobacco exposure is not well understood. Individual genetic susceptibility factors have been suggested to contribute to lung cancer risk in this population. Mutations in the p53 tumor suppressor gene are implicated in the development of lung cancer as they are frequently found in lung tumors from both smokers and never-smokers. In order to determine whether genetic polymorphisms affecting DNA repair capacity modulate p53 mutations in lung tumors from never-smokers, we compared p53 mutations with genotypes of XPD 312, XPD 751, and XRCC1 399 in lung tumors from 43 lifetime never-smokers. p53 mutations were identified in 10 (23%) cases and consisted mostly of G/C to A/T transitions. No statistically significant association was found between p53 mutations and genotypes of XPD 312 or XPD 751. However, patients with the XRCC1 399 Gln allele, that results in a lower base excision repair capacity, were more likely to have p53 mutations, compared with patients the wild-type Arg allele (P = 0.03). In addition, the p53 mutation frequency increased with an increasing number of combined genotypes associated with a lower DNA repair capacity of XPD 312, XPD 751, and XRCC1 399 (P = 0.02). These results suggest that individuals who never smoked and had XRCC1 399 Gln allele may be at a greater risk of p53 mutations, especially if combined with the genotypes of XPD 312 and XPD 751 that may result in a lower DNA repair capacity.     

The association of XPC polymorphisms and tea drinking with colorectal cancer risk in a Chinese population

The xeroderma pigmentosum complementation group C (XPC) is responsible for removal of bulky helix-distorting DNA lesions. Several polymorphisms of XPC gene may modulate the colorectal cancer (CRC) susceptibility. We assessed the association of XPC Lys939Gln (A/C), Ala499Val (C/T), and PAT (-/+) polymorphisms with CRC risk in a population-based case-control study which included 421 CRC patients and 845 controls. For Lys939Gln, the CC genotype was associated with a significantly increased risk of CRC (odds ratio (OR)=1.5; 95% confidence interval (CI)=1.0-2.2) compared with the AA genotype. The subjects with PAT +/+ genotype had a significantly increased risk of CRC (OR=1.5; 95% CI=1.0-2.3), compared with those with PAT-/- genotype. Though no significant association between Ala499Val and CRC risk was observed, we found that individuals carrying the CT+TT genotypes showed a significantly decreased risk of rectal cancer (OR=0.7; 95% CI=0.5-1.0). Additionally, the haplotype C+C was associated with a significantly increased CRC risk (OR=1.3; 95% CI=1.0-1.6), compared with the most common haplotype A-T. Further, individuals with four or more risk alleles exhibited a significantly increased risk of CRC (OR=1.4; 95% CI=1.0-2.0), with a significant gene-dosage effect (P for trend=0.038). Besides, never tea drinking was associated with a significantly increased risk of CRC (OR=2.3; 95% CI=1.7-3.3). Our results suggest that the XPC polymorphisms may modulate CRC susceptibility independently or jointly, and tea drinking has a protective effect on CRC.     

Polymorphisms at XPD and XRCC1 DNA repair loci and increased risk of oral leukoplakia and cancer among NAT2 slow acetylators

Polymorphisms at N-acetyl transferase 2 locus (NAT2) lead to slow, intermediate and rapid acetylation properties of the enzyme. Improper acetylation of heterocyclic and aromatic amines, present in tobacco, might cause DNA adduct formation. Generally, DNA repair enzymes remove these adduct to escape malignancy. But, tobacco users carrying susceptible NAT2 and DNA repair loci might be at risk of oral leukoplakia and cancer. In this study, 389 controls, 224 leukoplakia and 310 cancer patients were genotyped at 5 polymorphic sites on NAT2 and 3 polymorphic sites on each of XRCC1 and XPD loci by PCR-RFLP method to determine the risk of the diseases. None of the SNPs on these loci independently could modify the risk of the diseases in overall population but variant genotype (Gln/Gln) at codon 399 on XRCC1 and major genotype (Lys/Lys) at codon 751 on XPD were associated with increased risk of leukoplakia and cancer among slow acetylators, respectively (OR = 4.2, 95% CI = 1.2-15.0; OR = 1.6, 95% CI = 1.1-2.3, respectively). Variant genotype (Asn/Asn) at codon 312 on XPD was also associated with increased risk of cancer among rapid and intermediate acetylators (OR = 1.9, 95% CI = 1.2-2.9). Variant C-G-A haplotype at XRCC1 was associated with increased risk of leukoplakia (OR = 1.7, 95% CI = 1.2-2.4) but leukoplakia and cancer in mixed tobacco users (OR = 3.1, 95% CI = 1.4-7.1, OR = 2.4, 95% CI = 1.1-5.4, respectively) among slow acetylators. Although none of the 3 loci could modulate the risk of the diseases independently but 2 loci in combination, working in 2 different biochemical pathways, could do so in these patient populations.     

修复基因XRCC1 Arg194Trp位点多态性与肝癌易感性的关系

目的：探讨DNA损伤修复基因XRCC1多态与肝癌遗传易感性的关系。方法：本研究选取了130例肝癌患者及130例性别、年龄相匹配的正常对照者进行研究,采用限制性片段长度多态性方法,比较不同基因型与肝癌发病的关系。结果：变异型等位基因XRCC1 Arg/Trp及Trp/Trp的出现率在肝癌组和对照组中分别是27.69%和10.77%,（P〈0.05）;而野生基因型XRCC1 Arg/Arg出现率在肝癌组和对照组中分别是72.31和89.23%,（P〉0.05）。结论：XRCC1基因Arg194Trp位点单核苷酸多态在肝癌的发生过程中起着至关重要的作用。     

DNA损伤修复基因XRCC1和XPD遗传多态与晚期非小细胞肺癌对铂类药物的敏感性

目的 探讨DNA损伤修复基因XRCC1和XPD的遗传多态与晚期非小细胞肺癌（NSCLC）对以铂类为主化疗药物敏感性的关系。方法 以聚合酶链反应（PCR）结合限制性片段长度多态性（RFLP）,检测200例以顺铂（DDP）或卡铂（CBP）为主要化疗方案的NSCLC患者XRCC1 Arg194Trp和XPD Lys751Gln多态基因型,并比较不同基因型与化疗敏感性的关系。结果 化疗总有效（CR＋PR）率为36．0％,其中CR1例,PR71例,SD94例,PD34例。携带XRCC1第194位密码子Arg／Trp或Trp／Trp基因型的个体化疗敏感性是XRCC1第194位密码子Arg／Arg基因型携带者的2．48倍（95％CI为1．36～4．51,P=0．003）;未发现XPD Lys751Gln多态与化疗敏感性的相关性。联合分析这两个遗传多态发现,XRCC1 Arg194Trp和XPD Lys751Gln多态在NSCLC对铂类药物敏感性中存在一定的联合作用（趋势检验,P=0．004）。结论XRCC1 Arg194Trp和XPDLys751Gin遗传多态可能与NSCLC铂类药物敏感性有关。