Correlation of DNA Repair Gene Polymorphisms With Clinical Outcome in Patients With Locally Advanced Non–Small-Cell Lung Cancer Receiving Induction Chemotherapy Followed by Surgery

ObjectiveThe aim of this study was to evaluate whether xeroderma pigmentosum group D (XPD) and ribonucleotide reductase subunit M1 (RRM1) polymorphisms influenced clinical outcome in patients with stage IIIA-B non–small-cell lung cancer (NSCLC) treated with neoadjuvant gemcitabine/cisplatin/docetaxel followed by surgery.Materials and MethodsA total of 109 patients with stage IIIA and IIIB NSCLC were prospectively genotyped to examine a potential association between XPD 312 (aspartic acid [Asp]/asparagine [Asn]), XPD 751 (lysine [Lys]/glutamine [Gln]), and RRM1 (−37 C/A) polymorphisms with response and survival.ResultsThe median survival was 32.14 months for carriers of XPD 312 Asp/Asp and 12.04 months for those with the variant Asn allele (P = .05). In addition, event-free survival was longer for patients with the XPD 312 Asp/Asp genotype compared with patients with Asp/Asn or Asn/Asn (P = .03). A similar but nonsignificant trend was observed for the XPD 751 genotype. In a multivariate analysis, complete resection and age emerged as prognostic factors for overall survival; in patients with incomplete resection or exploratory thoracotomy, XPD 312 was the most significant prognostic factor (P = .03).ConclusionThe XPD 312 single nucleotide polymorphism is a prognostic factor for survival in patients with locally advanced NSCLC receiving induction chemotherapy followed by surgery. The Asn allele is associated with unfavorable outcome and could be used for better stratification of patients.     

XPD Polymorphisms and Risk of Squamous Cell Carcinoma of the Head and Neck in a Korean Sample

Objectives

XPD is a major player in nucleotide excision repair, which is one of the basic pathways of DNA repair. The objective of this study was to investigate the association of XPD single nucleotide polymorphisms (SNPs) and the risk of squamous cell carcinoma of the head and neck (SCCHN) in Koreans.

Methods

We performed XPD +23591G>A and +35931A>C genotyping in 290 SCCHN patients and 358 controls.

Results

The frequencies of the XPD +23591G>A (GG/GA/AA) genotypes were 89.0%/11.0%/0% in the patients and 90.3%/8.8%/0.9% in the controls, respectively. The odds ratio (OR) of the XPD +23591 GA genotype was 1.94 (0.92 to 4.08) in reference to the GG genotype. The frequencies of the XPD +35931A>C (AA/AC/CC) genotypes were 86.9%/12.0%/1.1% in the patients and 85.6%/13.8%/0.6% in the controls, respectively. The OR of the XPD +35931 AC and CC genotypes were 0.98 (0.51 to 1.88) and 2.68 (0.71 to 10.1), respectively, in reference to the AA genotype. On the subgroup analyses according to the smoking and drinking statuses, the SNPs and haplotypes of XPD showed no statistically significant association with the risk of SCCHN.

Conclusion

The results of this study suggest that the XPD +23591G>A and +35931A>C SNPs are not associated with the risk of SCCHN in Koreans; however, a further study with a larger number of subjects is necessary to verify this conclusion.     

XPD基因多态性与非霍奇金淋巴瘤发病风险

目的探讨核苷酸剪切修复基因(XPD)单核苷酸多态性与非霍奇金淋巴瘤(NHL)发病风险的关系。方法以309例NHL患者和305例健康对照者为研究对象,采用PCR-RFLP技术检测XPDG23591A、A35931C位点的基因多态。结果初步分析XPD G23591A和A35931C基因多态性与总的NHL无显著相关。对NHL亚类分析显示,在滤泡性淋巴瘤(FL)、弥漫性大B细胞淋巴瘤(DLBCL)、其他B细胞NHL和T细胞NHL中,XPD23591位点GA+AA型频率分别为16.3%、18.0%、10.5%、18.4%,对照组为12.5%,OR值分别为1.43、1.58、0.89和1.50,差异无统计学意义(P>0.05);XPD35931位点AC+CC型频率分别为15.2%、15.8%、18.4%、12.5%,对照组为11.5%,OR值分别为1.41、1.48、1.75和1.12,差异亦无统计学意义(P>0.05)。结论山东地区汉族人群XPD G23591A、G23591A位点多态性与非霍奇金淋巴瘤发病无关。     

Genetic polymorphisms in DNA repair gene APE1, XRCC1 and XPD and the risk of pre-eclampsia

Objective

Oxidative stress has been postulated as a major contributor to placental hypoperfusion and ischemia in pre-eclampsia (PE). Reactive oxygen species (ROS) generated during placental ischemia can cause oxidative damage to nucleic acids. Base excision repair (BER) and nucleotide excision repair (NER) are major pathways responsible for removing the oxidative DNA damage. Polymorphisms in DNA repair genes may be associated with differences in the repair efficiency of DNA damage.

Study design

In order to investigate the possible association between DNA repair genes and PE susceptibility, we analyzed genotype and allele distributions of APE1-148, XRCC1-194, XRCC1-399 and XPD-751 genes in 101 patients with PE and 107 healthy women. Differences in genotype distributions and allele frequencies in the cases and the controls were compared for statistical significance using the χ²-test. Haplotype frequencies were estimated using a contingency χ²-test. One-way ANOVA and Mann–Whitney U-test were used for the statistics of the clinical and biochemical parameters.

Results

No significant association between PE and the variant alleles of APE1 codon 148 (OR: 0.77, 95% CI = 0.51–1.15), XRCC1 codon 194 (OR: 0.64, 95% CI = 0.30–1.37), XRCC1 codon 399 (OR: 1.16, 95% CI = 0.78–1.74) and XPD codon 751 (OR: 1.21, 95% CI = 0.81–1.80) was observed. Results of our haplotype analysis demonstrated that there is a high linkage disequilibrium (D′: 1.0, r² = 0.042) between the haplotypes of XRCC1 codon 194 and codon 399 markers.

Conclusions

These preliminary results suggest that the polymorphic variants of APE1-148, XRCC1-194, XRCC1-399, and XPD-751 genes are not significant risk factors for PE development.     

ERCC1、ERCC2的多态性对常见消化系统肿瘤的影响

机体DNA修复系统如核苷酸切除修复在维持基因组功能整体性、修复致癌因素所致的损伤及抗癌过程中有着重要作用。一些核酸修复基因,如切除修复交叉互补基因1(ERCC1)及人类着色性干皮病基因D(XPD/ERCC2)的水平下降,可能会成为某种或某几种肿瘤的易感因素;但如果此种基因的水平较高,修复损伤的能力提高,对化疗药物所致基因损伤的修复能力也就增强了,那么可能对化疗药物产生耐药现象。以上两种基因的单核苷酸多态与以DDP、5-FU为基础的化疗方案的疗效存在一定关系,而消化道肿瘤又多应用铂剂及5-FU治疗,故本文对ERCC1、XPD/ERCC2与几种常见消化道肿瘤的发生及其化疗疗效的关系予以综述。     

ERCC2/XPD单核苷酸多态与苯并芘体外诱导DNA加合物损伤的关联性研究

目的评价环境致癌因子苯并芘(B[a]P)所致DNA损伤修复与ERCC2/XPD单核苷酸多态(SNP)的关联。方法收集282例辽宁地区汉族健康人群外周血8ml,常规提取淋巴细胞及DNA,采用Taqman实时定量PCR检测ERCC2/XPDLys751Gln(rs13181),Asp312Asn(rs1799793)和Arg156Arg(rs238406)的基因型;体外培养淋巴细胞,应用B[a]P及S9活化系统,诱导BPDE-DNA加合物的形成;高效液相色谱法检测BPDE-DNA加合物含量;分析BPDE-DNA加合物水平与ERCC2/XPD SNP位点的关联。结果携带ERCC2/XPD Arg156Arg位点AA基因型个体BPDE-DNA加合物水平显著高于CC基因型携带者;50～70岁和≥70岁年龄组人群的加合物水平高于≤30岁年龄组(P<0.05);多元线性回归分析同样显示,ERCC2/XPD Arg156Arg位点SNP及年龄对BPDE-DNA加合物含量的影响有统计学意义(P<0.05)。结论 ERCC2/XPD Arg156Arg位点A等位基因可能与BPDE-DNA加合物的DNA修复能力降低相关联,可能会增加肿瘤易感风险。     

DNA修复基因XPD XPC XRCC4基因多态性与结直肠癌易感性的关联性研究

  目的  探讨DNA修复基因XPD rs13181（codon751A/C,Lys751Gln）、rs238406（codon156C/A,Arg156Arg）、XPC rs2279017（i11C/A）和XRCC4 rs3734091（codon247T/C,Ala247Ser）的单核苷酸多态性与结直肠癌易感性的关系。  方法  采用TaqMan技术对2013年4月至2016年1月北京肿瘤医院收治的338例结直肠癌患者（病例组）和315例健康者（对照组）进行多态位点基因型的检测。  结果  XPD rs13181基因型GT和等位基因G增加个体结直肠癌的发病风险（GT>TT,adjusted OR=1.69,95%CI:1.15~2.47,P=0.007;G>T,adjusted OR=1.77,95%CI:1.19~2.64,P=0.005）;XRCC4 rs3734091基因型GT和等位基因T增加个体结直肠癌的易感性（GT>GG,adjusted OR=9.02,95%CI:5.61~14.50,P＜0.001;T>G,adjusted OR=4.06,95%CI:2.49~6.61,P＜0.001）;XPD rs13181和rs238406的单倍体型GT显著降低结直肠癌的发病风险（adjusted OR=0.39,95%CI:0.18~0.85,P=0.018）。XPCrs2279017等位基因G和XRCC4 rs3734091等位基因T的联合效应（adjusted OR=28.43,95%CI:6.85~117.95,P＜0.001）以及XPD rs13181等位基因G和XRCC4 rs3734091等位基因T的联合效应（adjusted OR=10.24,95%CI:4.69~22.35,P＜0.001）显著增加个体结直肠癌的易感性。  结论  XPD rs13181和XRCC4 rs3734091位点的多态性与结直肠癌的易感性相关。      

人剪切修复基因XPD对肝癌细胞生长及ERG基因的影响

目的探讨人剪切修复基因XPD转染人肝癌细胞SMMC-7721后对细胞自身生长及癌基因ERG表达的影响。方法将XPD基因通过LipofectamineTM2000转染入人肝癌细胞SMMC-7721。实验分为4组,分别为重组质粒转染细胞SMMC-7721-pEGFP-N2-XPD组(XPD组)、空载质粒转染细胞SMMC-7721-pEGFP-N2组(N2组)、脂质体转染细胞SMMC-7721组(脂质体组)、肝癌细胞SMMC-7721无转染空白对照组(空白对照组)。分别用逆转录聚合酶链反应(RT-PCR)和Westernblot法检测各组细胞中XPD、ERG的mRNA和蛋白质的表达量,用四甲基偶氮唑盐比色法(MTT)检测各组细胞的增殖活力及流式细胞仪检测各组细胞的凋亡情况。结果与其他3组比较,XPD组中的ERGmRNA及蛋白表达量显著降低,而XPDmRNA及蛋白表达量明显升高(P<0.01)。转染了XPD的肝癌细胞SMMC-7721,其细胞增殖活性(0.455±0.009)显著降低,细胞凋亡率(42.06±0.01)%明显升高(P<0.001)。结论 XPD基因可以抑制癌基因ERG的表达,明显降低肝癌细胞的增殖活力并提高肝癌细胞的凋亡率。     

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.     

Use of biomarkers to characterize functions of polymorphic DNA repair genotypes

Inheritance of variant DNA repair genes is believed to influence individual susceptibility to the development of environmental cancer. However, the validity of the belief is dependent upon understanding the functions of the variant genes. Consequently, a variety of studies have been conducted to investigate the functions of variant DNA repair genes, e.g. using biomarkers. These studies on several representative polymorphic DNA repair genes are reviewed in this report. From a general overview, it appears that the biomarker investigations did not provide consistent observations. However, from a more careful evaluation, it is clear that the inconsistencies are probably caused by the use of populations and biomarkers that are not appropriate for investigating the repair activities of the genes. For example, the use of cigarette smokers and patients may not generate precise information for this type of investigations because these conditions can modify the functions of the investigated genes. Thus, the use of healthy non-smokers would be more appropriate. Other problems with these studies includes the small sample size used and the fact that some of the biomarkers used, such as sister chromatid exchanges, are not appropriate because the mechanisms for formation of the biomarkers and their biological significance are unknown. Nevertheless, the following conclusions can be derived from the review of the various biomarker studies that have been published. XRCC1 194Trp, OGG1 326Cys and APE1 148Glu probably have limited alterations in repair activities compared to the wild-type genotypes. XRCC1 399Gln and XRCC3 241Met are deficient in the repair of X-ray-, but not UV-light-induced chromosome aberrations, therefore the variant genes are defective in base excision repair. XPD 312Asn and XPD 751Gln are deficient in the repair of UV-light- but not X-ray-induced chromosome aberrations, therefore they are defective in nucleotide excision repair.