中国公共卫生  2009, Vol. 25 Issue (7): 802-804   PDF    
引用本文
祁荣, 宋铁华, 马业罡, 刘峥嵘, 孙晓玲, 孙中芙, 尹娇杨. 女性肺癌易感性与DNA修复基因多态性[J]. 中国公共卫生, 2009, 25(7): 802-804.
QI Rong, SONG Tie-hua, MA Ye-gan, et al. Polymorphisms of DNA repair gene XRCC1 Pro206Pro and Gln632Gln and genetic susceptibility of lung cancer among non-smoking Chinese women[J]. Chinese Journal of Public Health, 2009, 25(7): 802-804.
女性肺癌易感性与DNA修复基因多态性
祁荣1, 宋铁华1, 马业罡2, 刘峥嵘3, 孙晓玲4, 孙中芙1, 尹娇杨1     
1. 沈阳医学院辽宁省高校环境与人口健康重点实验室, 沈阳 110034;
2. 辽宁省肿瘤医院胸外科;
3. 辽宁省人民医院普外二科;
4. 沈阳东方医疗集团菁华医院
收稿日期: 2008-11-12
基金项目: 国家自然科学基金(30571016);辽宁省教育厅高等学校科学研究项目(A类, 05L438)
作者简介: 祁荣(1973-), 女, 辽宁人, 高级实验师, 本科, 主要从事分子生物学实验研究。
通讯作者: 尹娇杨
摘要: 目的 研究非吸烟女性群体中DNA修复基因XRCC1 (X-ray repair complementing defective repair in Chinese hamster cell 1)同义突变多态与肺癌遗传易感性. 方法 选择肿瘤医院55例非吸烟女性肺癌患者, 74名正常对照者进行PCR-限制性片段长度多态性(RFLP)分型, 分析XRCC1 Pro206Pro和Gln632Gln多态/单体型与肺癌的关联. 结果 XRCC1 Pro206Pro (G)变异等位基因携带者与AA野生等位基因纯合子个体相比较, 肺癌发生风险为3.93倍(OR=3.93, 95% CI=1.47~10.52, P < 0.004);单体型在肺癌组与对照组之间的总体分布差异有统计学意义(P=0.005);由2个同义突变等位基因结合的单体型1[Pro206Pro (G)-Gln632Gln (A)]是高风险性单体型(OR=4.04, 95% CI=1.36~11.96, P=0.007);2个多态之间存在强烈的连锁不平衡(D'=0.702). 结论 非吸烟女性群体中, XRCC1 Rro206Pro (G)等位基因及含其等位基因的单体型可能是肺癌易感性的重要因素.
关键词： DNA修复基因XRCC1     遗传多态性     肺癌     非吸烟女性    
Polymorphisms of DNA repair gene XRCC1 Pro206Pro and Gln632Gln and genetic susceptibility of lung cancer among non-smoking Chinese women
QI Rong, SONG Tie-hua, MA Ye-gan, et al     
Key Laboratory of Environment and Population Health of University in Liaoning Province, Shenyang Medical College, Shenyang 110034, China
Abstract: Objective To assess the relationship between the polymorphisms of DNA repair gene XRCC1 Pro206Pr and Gln632Gln and susceptibility of lung cancer among non-smoking Chinese women. Methods A hospital-based case-control study consisting of 55 newly diagnosed and previously untreated subjects with lung cancer and 74 cancer-free control subjects matched on age (±3 years), gender and ethnicity was conducted.All subjects were unrelated ethnic Han Chinese and lifetime non-smoking women from northeastern China.Genotypes were determined by PCR-RFLP method. Results Variant G-allele of XRCC1 Pro206Pro was significantly over-represented in lung cancer patients (G versus A, OR=3.69, 95% CI=1.46-9.34, P=0.004).Carriers of the variant G-allele of Pro206Pro were at significantly increased risk of lung cancer (AG+GG versus AA, OR=3.93, 95% CI=1.47-10.52, P=0.004).No significant effect was observed for polymorphism of XRCC1 Gln632Gln.Overall haplotype distribution was significant different between cases and controls (P=0.005).Hapolotype (Pro206Pro〔G〕-Gln632Gln〔A〕) defined by combination of variant alleles in the two polymorphisms was a high-risk haplotype of lung cancer susceptibility (OR=4.04, 95% CI=1.36-11.96, P=0.007).The two polymorphisms were in strong linkage disequilibrium (D'=0.702). Conclusion The present results are consistent with our previous findings that variant G-allele of DNA repair gene XRCC1 Pro206Pro or a haplotype encompassing it's alleles may be an important susceptibility factor in the process of lung cancer developonent in non-smoking Chinese women.Larger sample studies will be required further to validate these findings.
Key words: DNA repair gene XRCC1     genetic polymorphism     lung cancer     non-smoking women    

肺癌是一种多基因遗传病。DNA修复系统基因的遗传变异与癌症发生风险相关联。碱基切除修复(base excision repair, BER)是DNA修复系统之一。XRCC1 (X-ray repair complementing defective repain in Chinese hamster cell 1)蛋白分子是BER的重要组成成分〔1〕。XRCC1基因的功能意义尚不明确〔1〕。流行病学研究表明, DNA修复基因XRCC1同义突变单核苷酸多态性(single nucleotide polymorphism, SNP)和癌症发生风险有关联〔2-4〕, 我们也报道了中国人群DNA修复基因XRCC1多态/单体型与肺癌易感性相关联〔5〕。为了进一步验证XRCC1 Pro206Pro (rs915927)与Gln632Gln (rs3547)多态/单体型与肺癌易感性的关联, 对非吸烟女性群体进行了调查。

1 对象与方法 1.1 对象

原发性肺癌55例和正常对照74名, 均为无亲缘关系的中国东北地区汉族人。病例为2002年3月-2006年3月在辽宁省肿瘤医院进行手术治疗的非吸烟女性患者。肺癌患者经术后组织病理学确诊, 并且尚未进行化疗、放疗及抗癌药物治疗。对照组的血样来自于同地区骨科病房非癌症个体。对照组与肺癌患者年龄(±3岁)、性别和民族相配对。所有研究对象均知情同意。

1.2 基因分型

采集1.5 mL外周血, 提取DNA, 使用Pure-gene DNA Isolation kit (Gentra Systems, Minneapolis, MN, USA)。基因分型采用改进的PCR-限制性片段长度多态性(RFLP)方法〔5〕。分型采用双盲法及阴性和已知基因型的对比控制。50%基因分型被重复, 其结果完全一致。分型成功率为94%。PCR引物(大连宝生物公司合成); 限制性内切酶(新英格兰生物实验室公司)。Pro206Pro: PCR引物为: F-GTC CCA TAG ATA GGA GTG AAA G; R-CCC TAG GAC ACA GGA GCA CA; 限制性内切酶为: MSPI[432 bp (A); 344, 88 bp (G)]。Gln632Gln: PCR引物为: R-GAG TGG CTG GGG AGT AGG A; F-GCC AAG CAG AAG AGA CAA A, 限制性内切酶为: HAE Ⅲ[256, 300 bp (A); 256, 192, 108 bp (G)]。

1.3 统计分析

应用SHEsis program〔6〕或SPSS 11.5软件进行Hardy-Weinberg平衡检验、基因频率、基因型频率、连锁不平衡、单体型频率、χ2检验(或Fisher's确切检验)、比值比(OR)和95% CI。所有统计学检验均为双侧概率检验。

2 结果 2.1 临床资料

肺癌组与对照组平均年龄差异无统计学意义(t'=0.18), 肺癌组(56±11)岁; 对照组(58±11)岁; 2组肺癌家族史差异有统计学意义[P=0.03(Fisher's确切检验)], 肺癌组(7.3%)有家庭史的人群比例明显高于对照组(0.0%)。

2.2 基因型分布与肺癌易感性(表 1)
表 1 XRCC1 Pro206和Gln632Gln SNPs基因型频率与肺癌易感性

对照组2个多态的基因型频率分布均符合Hardy-Weinberg遗传平衡定律[P=0.67, (Pro206Pro), P=0.34 (Gln632Gln)]。表 1可见, XRCC1 Pro206Pro (G)变异等位基因频率在肺癌组中差异有统计学意义的过高表达(G比A, OR=3.69, 95% CI=1.46~9.34, P=0.004); XRCC1 Pro206Pro (G)变异等位基因携带者与AA野生等位基因纯合型个体比较, 肺癌发生风险为3.93倍(OR=3.93, 95% CI=1.47~10.52, P=0.004)。对XRCC1 Gln632Gln单一SNP位点基因及基因型频率分布分析均未发现差异有统计学意义。

2.3 2个SNPs单体型频率及组成(表 2)
表 2 XRCC1 Pro206和Gln632gln SNPs单体型分析

2个SNPs所形成的4种可能的单体型, 均能被SHEsis软件所分析(SHEsis软件计算时默认值, 对于2个研究组, 如频率均 < 0.03的单体型将被自动删除), 但单体型3的OR值和95% CI值不能被计算。单体型在肺癌组与对照组之间的总体分布差异有统计学意义(P=0.005)。由2个多态的变异等位基因组成的单体型1是高风险性单体型(OR=4.04, 95% CI=1.36~11.96, P=0.007)。2个SNPs之间存在显著的连锁不平衡(D'=0.72)。

3 讨论

XRCC1基因定位在染色体19q 13.2区域, 它包含17个外显子及633个氨基酸, 目前已验证了XRCC1基因的60多个SNPs, 其中大约30个SNPs位于外显子或启动子区域〔1〕。研究涉及了XRCC1基因的2个外显子区的2个同义突变SNPs, 同义突变并不导致氨基酸的替换, 然而它可能影响mRNA的水平或转录效应。

XRCC1基因多态与不同癌症之间的遗传流行病学关联研究报道最多的是3个错义突变的多态: Arg195Trp, Arg280His和Arg399Gln。在一些研究中, Arg194Trp与肺癌、乳腺癌和膀胱癌发生风险相关联; Arg280His与肺癌和结直肠癌发生风险相关联; Arg399Gln与肺癌、乳腺癌、食管癌、前列腺癌、白血病、结直肠癌〔1〕和胃癌〔7〕发生风险相关联。反之, 一些研究未发现XRCC1基因与癌症发生风险相关联〔1〕。同一基因内的〔8-10〕或与其他变异等位基因结合的〔11-15〕单体型分析表明: XRCC1与肺癌、乳腺癌、食管癌、前列腺癌、白血病和胃癌发生风险相关联。

XRCC1基因多态与非吸烟女性肺癌易感性关联研究并不多见, 李鸣川等〔16〕对50例非吸烟女性肺癌配对病例-对照研究结果显示, XRCC1 Arg399Gln Gln/Gln基因型与非吸烟中国女性肺腺癌遗传易感性相关联。在丹麦高加索群体中, 未发现XRCC1 Pro206Pro或XRCC1 Gln632Gln与皮肤基底细胞癌发生风险相关联〔2〕。美国和英国高加索群体研究〔3, 4〕也未发现XRCC1 Pro206Pro或Gln632Gln与皮肤癌及膀胱癌发生风险相关联。

研究结果支持先前的发现〔5〕:中国人群中, 同义突变的XRCC1 Pro206Pro等位基因或者是在同一基因内或者是在其基因附近与其紧密连锁的其他多态可能是肺癌易感性的重要因素。

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