XRCC1和XRCC3单核苷酸多态性与晚期非小细胞肺癌铂类药物化疗疗效的相关性

背景与目的 DNA修复基因多态性预测铂类药物化疗敏感性对非小细胞肺癌(non-small cell lung cancer,NSCLC)个体化治疗具有重要意义.本研究旨在探讨X线修复交错互补基因1(X-ray repair cross complementing gene 1,XRCC1)和X线修复交错互补基因3(X-ray repair cross complementing gene 3,XRCC3)单核苷酸多态性与晚期NSCLC患者对铂类药物化疗疗效的关系.方法 采用PCR-RFLP方法检测130例以含铂方案化疗的晚期NSCLC患者外周血DNA中XRCC1 Arg194 Trp、Arg399 Gln和XRCC3 Thr241 Met基因多态性,分析其基因型与化疗疗效的关系.结果 130例晚期NSCLC患者采用含铂方案化疗2个周期后,化疗总有效率为33.8％.XRCC1 194和399基因多态性与铂类药物化疗敏感性相关,而XRCC3 241基因多态性与化疗敏感性无关(P=0.145).携带至少1个XRCC1 194 Trp等位基因者化疗有效率至少是携带Arg/Arg基因型患者的2.5倍(42.1％vs22.2％,OR=2.545,95％CI:1.159-5.590,P=0.020).携带XRCC1399 Arg/Arg基因型者的化疗有效率为45.5％,明显高于携带至少1个Gln等位基因者(21.9％)(OR=0.336,95％CI:0.156-0.722,P=0.005).XRCC1 194和399基因多态性之间存在联合作用,同时携带至少1个XRCC1 194 Trp等位基因和399 Arg/Arg基因型者的化疗有效率明显高于同时携带194 Arg/Arg和399 Arg/Gln基因型者(44.4％ vs 18.8％,OR=3.467,95％CI:1.223-9.782,P=0.019).XRCC1和XRCC3基因多态性在化疗敏感性方面存在一定的联合作用,携带至少1个XRCC1 194 Trp等位基因和399 Arg/Arg野生型基因同时又携带XRCC3 241 Thr/Met基因型者的化疗有效率明显高于其它基因型携带者.结论 XRCC1和XRCC3的多态联合可能与晚期NSCLC患者对铂类药物化疗疗效具有相关性.     

NP方案联合放疗治疗Ⅲ期NSCLC的近期疗效与XRCC1基因Codon399单核苷酸多态性的相关性

目的探讨XRCC1基因Codon399单核苷酸多态性与NP方案联合放疗治疗Ⅲ期非小细胞肺癌(NSCLC)近期疗效的关系。方法 52例Ⅲ期NSCLC患者,治疗前抽取静脉血,抽提全血基因组DNA,进行PCR扩增,对扩增产物行连接酶检测反应扩增,应用测序仪电泳分析得出XRCC1 Codon399基因型,分析Ⅲ期NSCLC化疗联合放疗有效组及无效组XRCC1基因Codon399单核苷酸多态性的分布情况。结果 52例NSCLC患者NP方案化疗联合放疗,总有效率为50.00%;XRCC1基因Codon399等位基因频率有效组和无效组分布情况无统计学差异(P>0.05);Codon399Arg/Arg、Arg/Gln+Gln/Gln基因型治疗有效率分别为54.16%、46.42%,两者比较差异无统计学意义(P>0.05)。结论 XRCC1基因Codon399单核苷酸多态性与NP方案联合放疗治疗Ⅲ期NSCLC的近期疗效无相关性。     

ERCC 1和XRCC 1多态与非小细胞肺癌GP方案化疗敏感性的研究

目的:探讨DNA修复酶基因ER-CC1 118和XRCC1 194多态性与非小细胞肺癌(NSCLC)患者对吉西他滨/顺铂(GP)方案化疗敏感性的关系.方法:收集经病理确诊的NSCLC 57例,化疗前均抽静脉血,提取白细胞DNA,用PCR-RFLP技术检测ER-CC1 118和XRCC1 194基因型.患者均经GP化疗方案治疗.结果:1)在NSCLC患者中,ERCC1 118 C/C、C/T和T/T基因型频度分别为48.2%、51.9%和0;XRCC1 194Arg/Arg、Arg/Trp和Tm/Tm基因型频度分别为52.6%、40.4%和7.0%.化疗后,57例患者中19例有效,总有效率为33.3%.2)ERCC1 118 C/C和C/T基因型者的化疗有效率分别为23.1%和46.4%,差异无统计学意义,X2=3.164,P=0.075;XRCC1 194Trp/Trp和Arg/Arg基因型者的化疗有效率分别为50.0%、52.2%和16.7%.携带Trp等位基因者的化疗有效率(51.9%)显著高于A.Rg/Arg基因型者,x2=6.41,P=0.0113.XRCCl 194与ER-CC1 118多态之间在化疗敏感性方面存在明显的交互作用,同时携带XRCC1 194 Arg/Arg和ERCC1 118 C/C基因型者的化疗有效率仅为6.3%(1/16),而携带XRCC1 194Trp等位基因同时携带ERCC1 118 C/C、C/T基因型,其化疗的有效率均显著提高,P=0.011 9和0.007 6.结论:DNA修复酶基因ERCC1 118和XRCC1 194多态与NSCLC对GP方案化疗的敏感性有关,患者的基因型检测有可能作为预测NSCLC对GP方案化疗敏感性的指标.中华肿瘤防治杂志,2009,16(1),27-30     

ERCC1和XRCC1多态性与进展期非小细胞肺癌对铂类化疗的敏感性

目的探讨DNA修复基因ERCC1 118C/T和XRCC1 Arg194Trp多态性与进展期非小细胞肺癌(non-small cell lung cancer,NSCLC)患者铂类药物化疗敏感性的关系。方法采用PCR-RFLP技术检测149例经病理确诊的接受含铂两药方案化疗的NSCLC患者外周血ERCC1 118和XRCC1 194位点的基因型,并分析其与化疗疗效的关系。结果经2个周期化疗后,149例进展期NSCLC患者化疗有效率为32.9%。携带至少1个ERCC1 118T突变基因患者的化疗有效率至少是C/C野生型基因携带者的3倍(49.1%vs 23.4%,OR=3.156,95%CI:1.548～6.334,P=0.001)。携带至少1个XRCC1 194Trp突变基因患者的化疗有效率显著高于Arg/Arg基因型携带者(41.3%vs 23.2%,OR=2.326,95%CI:1.138～4.753,P=0.019)。ERCC1 118C/T和XRCC1 Arg194Trp 2个基因多态之间存在一定的联合作用,携带至少1个ERCC1 118 T突变基因同时又携带至少1个XRCC1 194Trp突变基因型者的化疗有效率明显高于同时携带ERCC1 118C/C和XRCC1 194Arg/Arg野生型基因者(66.7%vs 17.1%,OR=9.714,95%CI:3.104～30.406,P<0.001)。结论与单基因检测比较,2个基因的联合检测在预测铂类药物化疗敏感性中的价值更大。ERCC1 118和XRCC1 194基因多态联合与NSCLC患者对铂类药物化疗敏感性相关,ERCC1和XRCC1基因型的联合检测有可能成为预测铂类药物化疗敏感性的指标。     

汉族晚期大肠癌ERCC1和XRCC1基因多态性与奥沙利铂化疗敏感相关性的研究

目的:探讨ERCC1Asn118Asn和XRCC1Arg399Gln多态性与中国汉族晚期大肠癌患者对奥沙利铂(Oxaliplatin,L-OHP)一线化疗临床效果的关系。方法:62例晚期大肠癌患者化疗前抽取静脉血并提取DNA,以RT-PCR法对ERCC1、XRCC1基因进行SNP分型。患者接受奥沙利铂为主的化疗方案化疗,比较不同基因型与化疗效果的关系。结果:ERCC1Asn118Asn基因突变频率为:C/C53.23%(33/62),C/T37.10%(23/62),T/T9.67%(6/62);XRCC1Arg399Gln基因突变频率为:G/G50.00%(31/62),G/A37.10%(23/62),A/A12.90%(8/62)。62例患者化疗2～3个周期后评价临床获益率为54.84%。ER-CC1基因Asn118Asn基因型C/C与C/T T/T在化疗获益组和化疗不敏感组中分布差异有统计学意义,χ2=6.289,P=0.021。XRCC1基因Arg399Gln基因型G/G与G/A A/A在化疗获益组和化疗不敏感组中分布差异也有统计学意义,χ2=6.513,P=0.021。两者联合多态性分析发现,同时携带ERCC1C/C和XRCC1G/G基因型患者化疗敏感性是同时携带ERCC1C/T T/T和XRCC1G/A A/A基因型患者的11.333倍,P=0.002。结论:ERCC1Asn118Asn、XRCC1Arg399Gln基因多态性与中国汉族晚期大肠癌患者接受奥沙利铂一线化疗后的临床效果有关。     

DNA修复酶XRCC1基因多态与非小细胞肺癌对GP方案化疗的敏感性

目的 研究DNA修复酶XRCC1基因Codon 194和Codon 399多态与非小细胞肺癌（NSCLC）患者对吉西他滨/顺铂（GP）方案化疗敏感性的关系.方法 收集经病理学确诊的NSCLC 57例,所有病例化疗前抽静脉血,提取白细胞DNA,用PCR-RFLP技术检测XRCC1 194和399基因型.所有患者均经PDD/GEM化疗方案治疗.结果 ①NSCLC患者中,XRCC1 194 Arg/Arg、 Arg/Trp 、Trp/Trp基因型者分别为30例（52.6%）、23例（40.4%）和4例（7.0%）;XRCC1 399 Arg/Arg、 Arg/Gln、Gln/Gln基因型者分别为31例（54.4%）、23例（40.3%）和3例（5.3%）.经化疗后,19例患者有效,总有效率33.3%.②XRCC1 194 Trp/Trp、Tp/Arg和Arg/Arg基因型者的化疗有效率分别为50.0%、52.2%和16.7%.携带Trp等位基因者的化疗有效率（51.9%）显著高于Arg/Arg基因型者（χ^2=6.41,P=0.0113）;XRCC1 399 Arg/Arg、Arg/Gln和Gln/Gln基因型者的化疗有效率分别为35.5%、34.8%和0,各组间的差异无显著性.XRCC1 194与XRCC1 399多态之间在化疗敏感性方面存在明显的交互作用,同时携带194 Arg/Arg和399 Arg/Arg基因型者的化疗有效率仅为7.7%（1/13）,而同时携带XRCC1 194 Trp等位基因和399 Arg/Arg基因型者的化疗有效率为58.8%（10/17）,2组之间差异显著（Fisher＇s双侧检验：P=0.0067）.结论 DNA修复酶基因XRCC1多态与NSCLC对GP方案化疗的敏感性有关,患者的基因型检测有可能作为预测NSCLC 对GP方案化疗敏感性的指标.     

XRCC1单核苷酸多态性预测晚期NSCLC铂类药物化疗的敏感性

目的研究XRCC1单核苷酸多态性与晚期非小细胞肺癌(non-small cell lung cancer,NSCLC)对以顺铂(cisplatin,DDP)或卡铂(carboplatin,CBP)为基础药物的化疗敏感性的关系。方法经病理学确诊的晚期NSCLC患者97例,采用DDP或CBP为基础药物的方案化疗,3个周期后进行疗效评价。以聚合酶链反应(PCR)结合限制性片段长度多态性(RFLP)检测XRCC1Arg194Trp和Arg399Gln基因型,并比较基因型与化疗敏感性的关系。结果(1)携带XRCC1194Arg/Trp的患者有效率高于携带Arg/Arg、Trp/Trp基因型的患者(P<0.05);携带至少一个Trp等位基因基因型患者的化疗敏感性是携带Arg/Arg基因型的3.4倍(OR=3.39,95%,CI=1.32~8.70,P<0.05)。(2)携带XRCC1399Arg/Arg、Arg/Gln、Gln/Gln基因型患者的有效率分别为36.4%、22.9%、28.6%,差异无统计学意义(P>0.05)。尚未发现XRCC1Arg194Trp和Arg399Gln基因多态性存在联合作用。结论XRCC1Arg194Trp单核苷酸多态性可能与晚期NSCLC对铂类药物的化疗敏感性相关。     

XRCC1单核苷酸多态与晚期非小细胞肺癌对铂类药物化疗敏感性的相关性

背景与目的DNA修复能力与肿瘤细胞对铂类药物的敏感性密切相关。本研究探讨DNA修复基因XRCC1单核苷酸多态性与非小细胞肺癌(non-smallcelllungcancer,NSCLC)患者对顺铂(cisplatin,DDP)或卡铂(carboplatin,CBP)为主的化疗方案敏感性的关系。方法经病理学确诊的晚期NSCLC患者105例,采用DDP或CBP为主的方案化疗,2～3个周期后进行临床疗效评价。以PCR-RFLP进行XRCC1Arg194Trp和Arg399Gln多态的基因分型,比较不同基因型对化疗敏感性的影响。比值比(OR)及其95%可信区间(CI)由logistic回归模型计算。结果携带至少一个Trp等位基因者化疗有效率为43.1%,显著高于携带Arg/Arg基因型的20.3%(OR=2.97,95%CI=1.15～7.72;P<0.05)。携带XRCC1399Arg/Arg基因型者化疗有效率为41.5%,显著高于携带至少一个Gln等位基因者的21.2%(OR=2.65,95%CI=1.03～6.87;P<0.05)。这两个多态之间存在联合作用,同时携带194Arg/Trp和399Arg/Arg基因型的患者,治疗有效率为66.7%,明显高于携带其它基因型的患者(有效率20.0%～23.1%)。结论XRCC1基因多态与NSCLC患者对铂类药物化疗的敏感性相关。     

XRCC1基因多态性与晚期非小细胞肺癌铂类药物化疗敏感性的关系

目的: 研究DNA修复基因XRCC1的T-77C和Argl94Trp多态性与晚期肺癌患者铂类药物化疗敏感性的关系.方法: 收集经病理学确诊的、接受铂类药物为基础的化疗的晚期肺癌患者107例,提取外周血DNA,用聚合酶链式反应-限制性片段长度多态性(PCR-RFLP)技术检测基因型,分析各基因型与疗效的关系.结果: XRCC1-77位点携带至少1个C等位基因患者的化疗有效率较野生型者提高约46%,但未达到统计学意义(OR:1.46,95%CI:0.56-3.79,P=0.441).XRCC1 194位点携带至少1个Trp等位基因患者的治疗有效率是野生型者的2.51倍(OR=2.51,95%CI:1.12-5.62,P=0. 025).结论: XRCC1 Argl94Trp多态性与晚期肺癌铂类药物化疗敏感性相关,但未能发现XRCC1 T-77C多态性与化疗疗效存在明显关联.     

BER通路中XRCC1多位点单核苷酸多态性与新疆不同民族喉癌易感性相关性研究

背景与目的:影响肿瘤遗传易感性的修复基因主要存在修复通路碱基切除修复(base excision repair,BER)途径,而X射线交错互补修复基因1(X-ray repair cross complementing group 1,XRCC1)是BER通路中的核心基因。近几年,国内外开展了许多有关基因多态性和喉癌易感性的研究。探讨BER通路DNA修复基因XRCC1多位点单核甘酸多态性与新疆不同民族喉癌易感性关系。方法:采用患者组与对照组的研究方法,选择58例喉癌(经病理证实为鳞状细胞癌)患者和120名体检正常的健康人对照,应用Multiplex SNa Pshot技术检测DNA碱基切除修复基因XRCC1的Gln632Gln(rs3547)、Arg399Gln(rs25487)、Arg280His(rs25489)、Arg194Trp(rs1799782)位点单核苷酸多态在患者组和正常对照组中的分布情况。结果:喉癌患者组中XRCC1Arg280His(rs25489)C/T(杂合型)及T/T(突变型)基因型的比例与对照组比较差异无统计学意义(P>0.05)。喉癌患者组中XRCC1的其余3个位点Gln632Gln(rs3547)C/T(杂合型)及T/T(突变型)基因型、Arg399Gln(rs25487)C/T(杂合型)及T/T(突变型)基因型、Arg194Trp(rs1799782)G/A(杂合型)及A/A(突变型)基因型的比例明显高于对照组(P<0.01)。其中汉、维、哈3个民族患者组Gln632Gln(rs3547)C/T(杂合型)及T/T(突变型)基因型、Arg399Gln(rs25487)C/T(杂合型)及T/T(突变型)基因型、Arg194Trp(rs1799782)G/A(杂合型)及A/A(突变型)基因型比例显著高于对照组(P<0.05),携带(rs3547)C/T及T/T基因型、(rs25487)C/T及T/T基因型、(rs1799782)G/A及A/A基因型个体较携带XRCC1(rs3547)C/C基因型、(rs25487)C/C基因型、(rs1799782)G/G基因型的个体患喉鳞状细胞癌的风险升高了分别为0.96倍、1.74倍、1.39倍;1.47倍、1.32倍、0.77倍,1.49倍、1.51倍、1.56倍。结论:汉、维、哈3个民族的XRCC1 Gln632Gln、Arg399Gln、Arg280His、Arg194Trp位点的单核苷酸多态性可能与喉癌遗传性有关联且有差异,XRCC1基因中的Gln632Gln、Arg399Gln、Arg194Trp位点的突变将导致喉癌的发病风险升高。而XRCC1基因中的Arg280His位点突变与喉癌发病的差异无统计学意义,可能该位点的突变与喉癌发病无关。     

XRCC1单核苷酸多态性与鼻咽癌铂类化疗敏感度的相关性

目的 探讨鼻咽癌铂类化疗敏感度与X射线交错互补修复基因1 codon194和codon399单核苷酸多态性的相关性。方法 收集广西医科大学第四附属医院2012年9月1日至2013年12月31日鼻咽部肿物活检确诊为鼻咽癌患者资料,采用限制性片段长度多态性聚合酶链反应技术检测鼻咽癌患者外周血DNA XRCC1 codon194和codon399单核苷酸多态性。顺铂+氟尿嘧啶方案诱导化疗2周期后复查MRI,按照RECIST 1.1标准评价其化疗敏感度,分析单核苷酸多态性（Single nucleotide polymorphism,SNP）与化疗敏感度的关系。结果 XRCC1 codon399 Gln/Gln基因型携带者化疗敏感度为Arg/Arg基因型携带者的3.500倍（P＜0.05）。XRCC1 codon399不含Arg基因型（即Gln/Gln）携带者化疗敏感度为含Arg基因型（Arg/Arg 和 Arg/Gln）携带者的3.274倍,（P＜0.05）。携带XRCC1 codon194各基因型患者化疗敏感度之间差异无明显统计学意义（P＞0.05）。结论 XRCC1 codon399 单核苷酸多态性有可能成为鼻咽癌铂类化疗敏感度的预测因子。     

Polymorphisms in DNA repair gene XRCC1 and increased genetic susceptibility to glioma

Background: The XRCC1 gene encodes the XRCC1 protein, which complexes with three other DNA repair enzymes involved in the base-excision repair (BER) pathways. Different XRCC1 polymorphisms may increase the risk of cancers by impairing interaction with other enzymatic proteins and consequently altering DNA repair activity, and result in carcinogenesis. Our study aimed to investigate any association between three polymorphisms of the XRCC1 gene at codon 194, 280 and 399 and potential glioma risk. Methods: We collected 127 patients with primary glioma and 249 controls who requested general health examinations from Union Hospital of Tongji Medical College hospital from March 2007 to September 2010. A total of 5 ml venous blood was drawn from each subject. The polymorphisms of XRCC1 gene at codons 194, 280 and 399 were analyzed based on duplex polymerase-chain-reactions with the confronting-two-pair primer (PCR-CTPP) method. Results: The homozygous Trp/Trp and heterozygotes Arg/Trp variants of codon 194 had a 2.12 fold and 1.46 fold increased risk of glioma compared to the homozygous Arg/Arg wide genotypes. The same effect was found in codon 399, the codon 399 Gln/Gln and Arg/Gln genotypes being associated with a 2.24 fold and 1.67 fold increased risk in glioma. When comparing the codon 194 Arg/Arg and 399 Arg/Arg genotypes, the combination of codon 194 Trp allele and 399 Gln allele had a heavy increase in glioma risk (OR=2.87, 95%CI=1.56-6.73). Conclusion: The present study provided evidence of a potential role for XRCC1 codon 194 and 399 polymorphisms in genetic predisposition to glioma among the Chinese population. This analysis of correlation of DNA repair genes and glioma may provide a deeper insight into the genetic and environment factors for cancer risk.     

Lack of Influence of XRCC1 and XPD Gene Polymorphisms on Outcome of Platinum-based Chemotherapy for Advanced Non Small Cell Lung Cancers

Purpose: Genetic polymorphisms of DNA repair genes are associated with differential enzyme activity andmay help explain interindividual differences in response rates after platinum-based chemotherapy for non smallcell lung cancers (NSCLCs). This study was conducted to assess relationships between X-ray repair crosscomplementing group1 (XRCC1) and xeroderma pigmentosum group D (XPD) genetic polymorphisms andoutcome in NSCLC patients. Methods: From March 1, 2005 to December 31, 2008, the polymerase chainreaction-restriction fragment length polymorphism method was applied to evaluate genetic polymorphisms ofthe XRCC1 codon399 (Arg/Gln) and XPD codon751 (Lys/Gln) DNA repair genes in 108 patients with stage IIIBand IV NSCLCs treated with platinum-based chemotherapy in the Department of Chemotherapy of JiangsuCancer Hospital and Research Institute. Results: Among the assessed NSCLC patients, the overall responserate of chemotherapy was 21.6%. No association was found with either of the genetic polymorphisms, althoughthe XRCC1 399Arg/Arg genotype was associated with a non-significant higher median survival time (29 monthsversus 21 months for the Arg/Gln genotype and 15 months for the Gln/Gln genotype, P=0.09). Conclusion: Ourresults suggested no influence of the XRCC1 codon399 (Arg/Gln) and XPD codon751 (Lys/Gln) geneticpolymorphisms on treatment response and survival in advanced NSCLC patients with platinum-basedchemotherapy.     

Prediction Value of XRCC 1 Gene Polymorphism on the Survival of Ovarian Cancer Treated by Adjuvant Chemotherapy

Objective: We conducted a prospective study to test the association between three amino acid substitutionpolymorphismic variants of DNA repair genes, XRCC1 (Arg194Trp), XRCC1(Arg280His) and XRCC1(Arg399Gln), and clinical outcome of ovarian cancer patients undergoing adjuvant chemotherapy. Methods:195 patients with primary advanced ovarian cancer and treated by adjuvant chemotherapy were included in ourstudy. All were followed-up from Jan. 2007 to Jan. 2012. Genotyping of XRCC1 polymorphisms was conductedby TaqMan Gene Expression assays. Results: The XRCC1 194 Trp/Trp genotype conferred a significant riskof death from ovarian cancer when compared with Arg/Arg (HR=1.56, 95%CI=1.04-3.15). Similarly, thosecarrying the XRCC1 399 Gln/Gln genotype had a increased risk of death as compared to the XRCC1 399Arg/Arg genotype with an HR (95% CI) of 1.98 (1.09-3.93). Conclusion: This study is the first to provide evidencethat XRCC1 gene polymorphisms would well be useful as surrogate markers of clinical outcome in ovariancancer cases undergoing adjuvant chemotherapy.     

Lack of any Relationship between Chemotherapy Toxicity in Non-small Cell Lung Cancer Cases and Polymorphisms in XRCC1 Codon 399 or XPD Codon 751

Purpose: To examine the association between genetic polymorphisms (at XRCC1codon 399 or XPD codon751) and chemotherapy related toxicities of non-small cell lung cancer. Methods: One hundred and fifteenpatients with histologically or cytologically confirmed stage IIIB and IV NSCLC recruited from Department ofChemotherapy of Jiangsu Cancer Hospital and Research Institute from 2005 to 2008, to evaluated the occurrenceof chemotherapy related toxicities and the association with single nucleotide polymorphisms in XRCC1codon399 or XPD codon 751. Results: No significant association was observed between grade 0 or grade 1-4 overalltoxicity and XRCC1 codon 399 (odds ratio=1.40, 95% confidence interval,0.73-2.66; adjusted odds ratio =1.43,95% confidence interval,0.71-2.88), or XPD codon 751 genetic polymorphisms (odds ratio =0.87, 95% confidenceinterval,0.33-2.26; adjusted odds ratio=0.74, 95% confidence interval,0.26-2.13); similar results were foundbetween hematologic, hepatic, gastrointestinal toxicities and XRCC1 399 or XPD 751 genetic polymorphisms.Conclusion: No statistically significant association was found between either XRCC1codon 399 or XPD codon751 genetic polymorphisms and chemotherapy related toxicities.     

Polymorphisms in DNA repair gene <Emphasis Type="Italic">XRCC1</Emphasis> and increased genetic susceptibility to breast cancer

X-ray repair cross-complementing 1 (XRCC1) gene encodes for a scaffolding protein, which plays an important role in base excision DNA repair by bringing together DNA polymerase beta, DNA ligase III and poly(ADP-Ribose) polymerase (PARP) at the site of DNA damage. Three polymorphisms of the XRCC1 gene at codons 194, 280 and 399 leading to a mino acid changes at evolutionary conserved regions are found to alter the efficiency of the resulting protein and may therefore constitute potential breast cancer risk. In the present study we sought to determine whether these genetic variants of the XRCC1 gene was associated with any increased risk of breast cancer among the South Indian women in a hospital based case control study using PCR-RFLP and DNA sequencing techniques. Our data showed a positive association between the polymorphisms of codons 194 (OR=1.98, 95% CI=1.13--3.48 for Trp allele) and 399 (OR=2.14, 95% CI=1.29--3.58 for Gln allele) and breast cancer risk. However, XRCC1 codon 280 genotype analysis showed no evidence for an association with increased risk of breast cancer. A combined analysis of the effect of XRCC1 codon 194 and 399 revealed the highest risk (OR=3.64, 95% CI=1.57--8.46) for carriers of the polymorphic alleles in both these codons. In conclusion, the present study suggested involvement of XRCC1 codon 194 and 399 polymorphisms in the genetic predisposition to breast cancer among South Indian women. Our preliminary results based on the analysis of functionally relevant polymorphisms in XRCC1 low penetrance gene may provide a better model that would exhibit additive effects on individual susceptibility to breast cancer.     

DNA repair gene polymorphism associated with sensitivity of lung cancer to therapy

This study aimed to investigate association between single-nucleotide polymorphisms (SNPs) of excision repair cross-complementing gene 1 (ERCC1), excision repair cross-complementing gene 2 (ERCC2), and X-ray repair cross-complementing group 1 (XRCC1) with sensitivity of advanced non-small cell lung cancer (NSCLC) patients to platinum-based chemotherapy. A total of 89 NSCLC patients were recruited and treated with two cycles of platinum-based chemotherapy. DNA was extracted from peripheral lymphocytes for detection of SNPs of ERCC1 Asn118Asn, ERCC2 Lys751Gln, and XRCC1 Arg399Gln. The overall response rate of these patients was 29.2%. There was no statistically significant difference of treatment response between the wild genotypes and the variant genotypes for the ERCC1 Asn118Asn and ERCC2 Lys751Gln gene. The distributions of genotypes XRCC1 Arg399Gln differed significantly between the response and non-response groups (76.9 vs. 23.1%, P = 0.001). The XRCC1 399Arg/Arg genotype carriers had a higher response rate than that of the Gln genotype carriers (OR = 4.81, 95%CI = 1.778-13.013, P = 0.002). The combination of the favorable genotypes of ERCC1, ERCC2, and XRCC1 had a higher response rate compared to that of patients with other genotypes. The combined polymorphisms of ERCC1, ERCC2, and XRCC1 may be associated with sensitivity of NSCLC to platinum-based chemotherapy. Further studies will verify these SNPs as biomarkers for prediction of platinum-based chemotherapy responses of NSCLC patients.