The <Emphasis Type="Italic">Arg</Emphasis>194<Emphasis Type="Italic">Trp</Emphasis> polymorphism in DNA repair gene XRCC1 and the risk for sporadic late-onset Alzheimer's disease

Abstract Alzheimer's disease (AD) is defined pathologically by the presence of β-amyloid plaques, neurofibrillary tangles and extensive neuronal loss. Evidence indicates that increased DNA damage may contribute to neuronal loss in AD. Recently, it has been shown that in AD neurons have a reduced capacity for some types of DNA repair. Polymorphisms in DNA repair genes may be associated with differences in repair efficiency of DNA damage. Variants of several DNA repair genes, including the base excision repair gene XRCC1, have been described previously. We hypothesised that Arg194Trp polymorphism of XRCC1 gene may contribute to genetic susceptibility for AD. In order to test this hypothesis, we investigated Arg194Trp polymorphism at the XRCC1 gene in the DNA samples of 98 patients with AD and 95 healthy subjects. The frequency of the Trp allele was more pronounced among cases (11.2%) compared with controls (5.8%). On combining the homozygous and heterozygous variants of each codon, the variants seemed to be at twofold risk of AD, although the risk estimates were not statistically significant (OR=1.95, 95% CI 0.88–4.34, p=0.09). In addition, the 194Trp allele revealed a borderline significance (OR=2.05, 95% CI 0.96–4.37, p=0.056). According to our results, it may be speculated that the polymorphic variants of XRCC1 codon 194 have a role in the development of AD.     

XRCC1、hOGG1基因多态性与喉癌遗传易感性的关系

目的 探讨X线修复交叉互补组1基因(X-ray repair cross complementing group 1,XRCC1)、8-羟基鸟嘌呤修复酶基因(human 8-oxoguanine glycosylase I,hOGG1)多态性与喉癌遗传易感性的关系.方法 采用病例-对照设计,应用聚合酶链反应-限制性片段长度多态性分析法检测了72例经病理确诊的喉癌患者和随机抽样的72例无肿瘤、无遗传病对照者XRCC1-Arg399Gln、hOGG1-Ser326Cys多态性.结果 病例组XRCC1第399位密码子杂合型(Arg/Gln)及突变型(Gln/Gln)和hOGG1第326位密码子杂合型(Ser/Cys)及突变型(Cys/Cys)分布频率均高于对照组(P＜0.05),与携带XRCC1-399野生型(Arg/Arg)、hOGG1-326野生型(Ser/Ser)个体相比,携带该基因型的个体喉癌的发病风险分别升高了3.37和2.54倍.交互作用分析显示,吸烟组与不吸烟组相比,携带XRCC1、hOGG1各基因型的个体的喉癌发病风险差异未发现存在统计学意义(xH12=0.15,xH22=0.28,P＞0.05).结论 XRCC1-399位点Arg→Gln和hOGG1-326位点Ser→Cys的氨基酸替换可能导致喉癌的发病风险增加,XRCC1-Arg399Gln、hOGG1-Ser326Cys多态性可能与喉癌的遗传易感性有关.     

DNA repair gene XRCC1 Arg399Gln polymorphism is associated with increased risk of uterine leiomyoma

BACKGROUND: DNA repair gene XRCC1 Arg399Gln polymorphism has been associated with the risk of several human tumours. In the present study we investigated whether the XRCC1 polymorphism is related to the risk of uterine leiomyoma, the most common neoplasm of the female genital tract. METHODS: Three hundred and twenty-seven patients with uterine leiomyoma and 197 normal controls were enrolled, and XRCC1 genotyping was determined by PCR and restriction fragment length polymorphism. RESULTS: The proportions of individuals homozygous for 399Arg allele, heterozygous and homozygous for the 399Gln allele were 85.8%, 13.7% and 0.5% among the control group, and 46.2%, 53.2% and 0.6% in those with leiomyoma (P < 0.001), respectively. Logistic regression analysis (after adjusting for age, parity, menarche age and body mass index) showed a significant increased risk of uterine leiomyoma in women with the Arg/Gln genotype versus the Arg/Arg genotype (odds ratio 6.79; 95% confidence interval 4.20-10.99; P < 0.001). CONCLUSIONS: In Korean women, the 399Gln polymorphism of XRCC1 is associated with an increased risk of uterine leiomyoma.     

广西人群DNA修复基因XRCC3多态性与肝细胞癌遗传易感性关联分析

目的 探讨DNA修复基因X线修复交叉互补因子3(X-ray cross-complementing group 3,XRCC3)基因Thr241Met多态性与黄曲霉毒素B1(aflatoxin B1,AFB1)相关性肝细胞癌(hepatocellular carcinoma,HCC)遗传易感性的相关性.方法 应用PCR技术对AFB1高污染区广西地区257例HCC患者和711名对照人群的XRCC3基因多态性进行检测,进行的病例对照研究.结果 (1)XRCC3 3种基因型(Thr/Thr、Thr/Met、Met/Met)中带有Met者与HCC的易感性相关,且这种相关性与Met数量呈正相关(校正风险值OR分别为2.20和8.56);(2)XRCC3突变基因型多态与血白细胞AFB1-DNA加合物水平在HCC发生过程中存在协同作用(校正OR:2.34～20.44,P＜0.01).结论 XRCC3多态性与HCC易感性相关,且这种多态性与AFB1暴露水平在HCC发生中存在协同作用.     

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。      

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。     

Confirmation of genetic variants associated with lethal prostate cancer in a cohort of men from hereditary prostate cancer families

Germline genetic variants have been suggested as prognostic biomarkers for identifying patients at high risk for lethal prostate cancer (PCa). Validation studies have confirmed the association of several single nucleotide polymorphisms (SNPs) with fatal PCa, but whether these variants affect PCa‐specific mortality (PCSM) in patients with an inherited predisposition to PCa, based on familial history, is unknown. For this study, a cohort of 957 PCa patients from 270 hereditary prostate cancer families of European ancestry was genotyped for a panel of 22 PCSM‐associated SNPs. Death certificates were reviewed to confirm cause of death. Mixed‐effect Cox proportional hazards models were used to assess survival according to genotypes, accounting for relatedness and clinicopathological factors. Within this cohort, 98 PCa deaths were confirmed over an average follow‐up period of 12.7 years after diagnosis. Variant allele carriers for three SNPs had significantly altered risk for PCSM [rs635261 at RNASEL, hazard ratio (HR), 0.35, 95% CI, 0.18–0.66; p = 0.002; rs915927 in XRCC1, HR, 1.91, 95% CI, 1.21–3.02; p = 0.009; and rs2494750 at AKT1, HR, 0.45, 95% CI, 0.23–0.90; p = 0.016). These results confirm the association of genetic variation in three genes with PCa lethality in a cohort of men with an inherited susceptibility to the disease and provide validation evidence that germline SNPs provide prognostic information for PCa patients. Development of a panel of germline biomarkers with clinical utility for distinguishing patients at detection who have an increased risk for fatal PCa is warranted.     

Alterations of DNA damage response pathway: Biomarker and therapeutic strategy for cancer immunotherapy

Genomic instability remains an enabling feature of cancer and promotes malignant transformation. Alterations of DNA damage response (DDR) pathways allow genomic instability, generate neoantigens, upregulate the expression of programmed death ligand 1 (PD-L1) and interact with signaling such as cyclic GMP–AMP synthase-stimulator of interferon genes (cGAS–STING) signaling. Here, we review the basic knowledge of DDR pathways, mechanisms of genomic instability induced by DDR alterations, impacts of DDR alterations on immune system, and the potential applications of DDR alterations as biomarkers and therapeutic targets in cancer immunotherapy.     

Worldwide Distribution of Four SNPs in X‐Ray and Repair and Cross‐Complementing Group 1 (XRCC1)

Purpose

X‐ray repair cross‐complementing group 1 (XRCC1) repairs single‐strand breaks in DNA. Several reports have shown the association of single nucleotide polymorphisms (SNPs) (Arg194Trp, Pro206Pro, Arg280His, Arg399Gln) in XRCC1 to diseases. Limited population data are available regarding SNPs in XRCC1, especially in African populations. In this study, genotype distributions of four SNPs in worldwide populations were examined and compared with those reported previously.

Materials and Methods

Four SNPs (Arg194Trp, Pro206Pro, Arg280His, Arg399Gln) in XRCC1 from genomic DNA samples of 10 populations were evaluated by using polymerase chain reaction followed by restriction fragment length polymorphism analysis.

Results

The frequency of the minor allele corresponding to the Trp allele of XRCC1Arg194Trp was higher in Asian populations than in African and Caucasian populations. As for XRCC1Pro206Pro, Africans showed higher minor allele frequencies than did Asian populations, except for Tamils and Sinhalese. XRCC1 Arg280His frequencies were similar among Africans and Caucasians but differed among Asian populations. Similarly, lower mutant XRCC1 Arg399Gln frequencies were observed in Africans.

Conclusions

This study is the first to show the existence of a certain genetic heterogeneity in the worldwide distribution of four SNPs in XRCC1.