Single nucleotide polymorphisms for DNA repair genes in breast cancer patients

BACKGROUND: The incidence rate for breast cancer (BC) has been increasing in many countries and BC still remains the most common form of cancer in female and continues to be a major health problem worldwide. We explored the association of single nucleotide polymorphisms (SNPs) in DNA repair genes with breast cancer. METHODS: SSCP and RFLP were used to analyze genotypes of DNA repair genes for NBS1, XPC, XPD and XRCC3. RESULTS: T/C in XRCC3 exon 7 had a somewhat deviation from HWE in BC group (P=0.08). The genotype frequency for heterozygote A/C in XPC exon 15 and T/C in XRCC3 exon 7, homozygote A/A in XPD exon 10 were significantly different between BC group and control group in Chinese population (P<0.05, OR=1.47, 95% CI, 1.00-2.16 for A/C in XPC exon 15; P<0.05, OR=1.79, 95% CI, 0.98-3.26 for T/C in XRCC3 exon 7; P<0.05, OR=0.51, 95% CI, 0.27-0.94 for G/A in XPD exon 10). For the SNPs in NBS1 exon 5 (Glu185Gln, G/C) and XPD exon 23 (Lys751Gln, A/C), no remarkable difference for genotype distributions and allele frequencies was observed between BC group and control group in the study. CONCLUSIONS: The genotypes of A/C in XPC exon 15, T/C in XRCC3 exon 7 and A/A in XPD exon 10 studied were significantly different between BC group and control group in Chinese population.     

DNA修复基因XPD、XPA单核苷酸多态性与乳腺癌发病风险的相关性研究

目的探讨人类着色性干皮病基因D(XPD)的rs238406,rs13181,rs3810366,rs1799793,rs50872及着色性干皮病基因A(XPA)的rs1800975单核苷酸多态性与南京地区女性乳腺癌发病风险、病理特征与乳腺癌相关激素受体水平的相关性。方法采用病例-对照研究,选取298例女性乳腺癌患者作为病例组,298例健康女性作为对照组,用Sequenom Mass Array技术检测6个多态性位点的基因型,Logistic回归模型分析不同基因型与乳腺癌发生、病理特征和相关激素受体水平包括雌激素受体(ER)、孕激素受体(PR)及原癌基因人类表皮生长因子受体2(HER2或Cer B-2)的关系。结果 rs3810366(χ2=14.993,P=0.001)、rs1800975(χ2=8.336,P=0.015)、rs50872(χ2=8.735,P=0.013)位点的各基因型在两组中分布差异有统计学意义。rs3810366 CG基因型(OR=0.54,95%CI:0.37~0.78)在乳腺癌组中的频率(31.54%)低于对照组(46.98%),GG/CG基因型发生乳腺癌的风险是健康人的0.71倍(OR=0.71,95%CI:0.51~1.00)。rs1800975位点的AG(OR=0.58,95%CI:0.39~0.85)、AA(OR=0.65,95%CI:0.42~0.90)、AA/AG(OR=0.60,95%CI:0.43~0.86)基因型与乳腺癌的发病风险均呈现负相关(OR1);rs50872 CT(OR=1.64,95%CI:1.16~2.32)及TT/CT(OR=1.66,95%CI:1.18~2.30)是乳腺癌的风险因素。ER及Cer B-2水平可影响rs3810366基因位点在病例组与对照组中分布(P0.01)。PR与Cer B-2水平影响rs1800975基因位点在两组中的分布(P0.05)。对rs50872位点进行分析,在ER、PR及Cer B-2水平正常时,基因型在病例组与对照组中分布差异有统计学意义(P0.01)。结论 XPD基因的rs3810366、rs1800975及rs50872位点的单核苷酸多态性与乳腺癌的发生风险具有相关性。对于不同基因位点,ER、PR及Cer B-2的水平与乳腺癌的发生、发展有关。     

Association of single nucleotide polymorphisms in IL-12 and IL-27 genes with colorectal cancer risk

ObjectivesInterleukin-12 (IL-12) plays an important role in antitumor immunity. Interleukin-27 (IL-27) is a novel IL-12 family member. The present studies demonstrate that IL-27 mediates potent antitumor activity. However, No studies have examined the association of these polymorphism with colorectal cancer (CRC). Therefore, we investigated the relationship of IL-12 and IL-27 gene polymorphisms and CRC.Design and methodsWe analyzed polymorphisms of IL-12 gene 16974 A/C and IL-27 gene ? 964 A/G, 2905 T/G, 4730 T/C in 410 patients with CRC and 450 controls, using PCR-RFLP method.ResultsThere were no significant differences in the genotype and allele frequencies of IL-12 and IL-27 gene polymorphisms between the group of patients with CRC and the controls. Furthermore, no association was found between IL-12 family gene polymorphisms and different clinical stages in patients with CRC.ConclusionThese findings suggest that IL-12 and IL-27 gene polymorphisms may not be involved in susceptibility to CRC.     

Single nucleotide polymorphisms in genes associated with isoniazid resistance in Mycobacterium tuberculosis

Isoniazid (INH) is a central component of drug regimens used worldwide to treat tuberculosis. Previous studies have identified resistance-associated mutations in katG, inhA, kasA, ndh, and the oxyR-ahpC intergenic region. DNA microarray-based experiments have shown that INH induces several genes in Mycobacterium tuberculosis that encode proteins physiologically relevant to the drug's mode of action. To gain further insight into the molecular genetic basis of INH resistance, 20 genes implicated in INH resistance were sequenced for INH resistance-associated mutations. Thirty-eight INH-monoresistant clinical isolates and 86 INH-susceptible isolates of M. tuberculosis were obtained from the Texas Department of Health and the Houston Tuberculosis Initiative. Epidemiologic independence was established for all isolates by IS6110 restriction fragment length polymorphism analysis. Susceptible isolates were matched with resistant isolates by molecular genetic group and IS6110 profiles. Spoligotyping was done with isolates with five or fewer IS6110 copies. A major genetic group was established on the basis of the polymorphisms in katG codon 463 and gyrA codon 95. MICs were determined by the E-test. Semiquantitative catalase assays were performed with isolates with mutations in the katG gene. When the 20 genes were sequenced, it was found that 17 (44.7%) INH-resistant isolates had a single-locus, resistance-associated mutation in the katG, mabA, or Rv1772 gene. Seventeen (44.7%) INH-resistant isolates had resistance-associated mutations in two or more genes, and 76% of all INH-resistant isolates had a mutation in the katG gene. Mutations were also identified in the fadE24, Rv1592c, Rv1772, Rv0340, and iniBAC genes, recently shown by DNA-based microarray experiments to be upregulated in response to INH. In general, the MICs were higher for isolates with mutations in katG and the isolates had reduced catalase activities. The results show that a variety of single nucleotide polymorphisms in multiple genes are found exclusively in INH-resistant clinical isolates. These genes either are involved in mycolic acid biosynthesis or are overexpressed as a response to the buildup or cellular toxicity of INH.     

Polymorphisms of estrogen synthesizing and metabolizing genes and breast cancer risk in Japanese women

Recent success of chemoprevention with tamoxifen has opened a new era wherein prevention of breast cancer is much more emphasized than treatment of established breast cancer. Since tamoxifen has been shown to reduce the risk of estrogen receptor (ER)-positive, but not ER-negative, breast cancer in the chemoprevention trial (P-1), it seems to be important to develop risk factors for ER-positive breast cancer in order to select the candidates for chemoprevention more appropriately. Estrogens, the major risk factors for breast cancer, are speculated to affect breast cancer risk through ER, thus, genetic polymorphisms of the genes involved in the estrogens biosynthesis and metabolism are expected as risk factors for ER-positive breast cancer. Significance of polymorphisms of the genes involved in estrogens biosynthesis (CYP17, CYP19) and metabolism (CYP1A1, CYP1B1, COMT) in modulating the susceptibility to breast cancer is reviewed. The ethnic difference of the variant allele frequencies between Caucasian women and Asian women is also discussed.     

中国汉族人群维生素D受体基因3′区域单核苷酸多态性与前列腺癌基因危险性的关系

背景前列腺癌发病率有显著的种族差异,近来已有研究报告显示维生素D受体基因(vitamin D receptor gene,VDRG)多态性与前列腺癌的发病危险性有关,但大多集中在高发病的欧美人群.目的研究低发病的中国汉族人群VDRG单核苷酸多态性(single nucleotide polymorphism,SNP)与前列腺癌的关系,探讨前列腺癌发病种族差异的原因.设计非随机对照研究.地点和对象329受试者(103例前列腺癌患者、112例前列腺增生及114例对照者)外周血标本,采集自北京大学第一医院.所有受试者来自北方地区的汉族人群,均知情同意.干预收集中国北方地区汉族人群103例前列腺癌患者、112例前列腺增生及114例对照者外周血标本,应用基于PCR的限制性酶切片段长度多态(restriction fragment length polymorphism,RFLP)和变性高效液相色谱(denaturing high performance liquid chxomatograpy,DHPLC)方法,检测VDRG 3′区域三个单核苷酸多态位点TaqI,BsmI和ApaI,并对该位点SNP分布进行分析.主要观察指标VDRG 3′区域三个单核苷酸多态位点TaqI,BsmI和ApaI在病例与对照组中的分布,VDRG SNP分布与中国汉族人群前列腺癌发病危险及疾病进展的关系.结果VDRG 3′区域三个SNP位点基因型和等位基因在北方地区汉族前列腺癌患者及对照中的分布频率无显著差异(P＞0.05),但TaqI和BsmI位点基因型频率分布与高发患者群相比有显著不同.器官局限性前列腺癌组(T1～T2)Tt基因型以及携带等位基因A的纯合子(AA)或杂合子(Aa)的频率明显高于对照组(P＜0.05),此外,在低分级组(Gleason＜7)携带等位基因A的纯合子(AA)或杂合子(Aa)的频率明显高于对照组(P=0.031).结论结果显示VDRG 3′区域多态性在低发病的中国汉族人群与前列腺癌发病危险无关,但VDRG多态性在预测前列腺癌疾病进展有一定作用,TaqI和BsmI位点基因型频率分布与高发患者群有明显差异,可能是前列腺癌发病种族差异的原因之一.     

XRCC1、XPD单核苷酸多态性与肺癌铂类化疗的临床预后研究

目的DNA修复基因XRCC1和XPD是参与铂-DNA加合物修复中的关键因子。探讨肿瘤石蜡组织中XR- CC1、XPD单核苷酸多态性与接受铂类药物化疗非小细胞肺癌(NSCLC)患者临床预后之间的关系。方法采用TaqMan探针Real-time PER方法评价53例石蜡包埋NSCLC组织中DNA修复基因XRCC1第399位密码子、XPD第751位密码子的多态性,并比较不同基因型与NSCLC肿瘤组织临床病理及铂类化疗预后之间的关系。结果XRCC1 Arg399Gln、XPD Lys751Gln基因多态性与NSCLC患者临床及肿瘤病理特征均未见相关性。携带XRCC1 Arg/Arg或Arg/Gln基因型NSCLC患者经铂类化疗后的平均总生存时间为24.0月,而携带Gln/Gln基因型患者仅为8.0月,两者有统计学差异(P=0.02)。XPD Lys751Gln与NSCLC患者无进展生存期和总生存时间均未见显著性差异(P>0.05)。XPD和XRCC1的多态性联合分析显示变异型等位基因的个数增加与总生存时间(P=0.015)相关。Cox比例风险模型显示XRCC1 Arg399Gln可以独立预测NSCLC患者的总生存时间(P=0.011)。结论XRCC1 Arg399Gln、XPD Lys751Gln基因多态性与NSCLC肿瘤临床病理特征无关。XRCC1 Arg399Gln基因多态性与NSCLC患者的总生存时间有关,在一定程度上可以作为判断NSCLC患者铂类药物化疗的预后指标。XRCC1和XPD SNP在铂类药物化疗预后方面可能存在一定的联合作用。     

BTNL2基因多态性与广东汉族女性乳腺癌易感性的相关性研究

目的探讨位于基因BTNL2（butyrophilin-like2）位点chr6-32478813和chr6-32470723的单核苷酸多态性（single nucleotide polymorphisms,SNP）与广东汉族女性乳腺癌易感性的关系。方法采用MassARRAY-IPLEX SNP分型技术,以南方医科大学南方医院的216例广东汉族女性乳腺癌患者及216例同期女性健康体检者为研究对象,对以上2个多态性位点进行基因分型,利用χ2检验统计分析病例组和对照组的基因型频率有无差异,非条件Logistic回归计算比数比（odds ratio,OR）和95%可信区间（confidence interval,CI）,由此评价这两个位点多态性与乳腺癌的相关性。随后,将病例组按雌激素受体（estrogen receptor,ER）和孕激素受体（progesterone receptor,PR）免疫组化结果的不同进行进一步的分层分析。结果位点chr6-32478813和chr6-32470723基因型分布频率在病例-对照分组分析中无统计学差异（P〉0.05）;而进一步的分析发现这两位点的基因型分布频率在ER阴性（-）与ER阳性（＋）乳腺癌分组中有一定的差别,但统计学意义不显著;在PR阴性（-）与PR阳性（＋）分组中,差异有统计学意义（P〈0.05）,携带杂合基因型（chr6-32478813,CT;chr6-32470723,GA）的个体更倾向于PR（-）乳腺癌（OR=0.53,95%CI：0.29～0.94,P=0.028;OR=0.44,95%CI：0.19～0.99,P=0.043）。结论 BTNL2基因chr6-32478813和chr6-32470723位点多态性与乳腺癌患病风险均无明显相关性,但两位点的杂合基因型均与乳腺癌组织PR阴性（-）明显相关。     

Single nucleotide polymorphisms in the apoptosis receptor gene TNFRSF6

The homotrimeric Fas receptor, an inducer of lymphocyte apoptosis, plays a critical role in cellular pathways of immune homeostasis and immunologic tolerance. Inherited and acquired defects in the Fas gene, TNFRSF6 (tumor necrosis factor receptor superfamily member 6) have been associated with human autoimmune lymphoproliferative syndrome (ALPS) and a spectrum of other complex autoimmune diseases and malignancies. In addition to over 60 deleterious mutations associated with dominant inhibitory defects or null mutations of TNFRSF6, several sequence variants have been noted. To facilitate interpretation of genotypes of this important locus, we sequenced DNA from unrelated, healthy Caucasians and African Americans. Two new and 12 previously recorded SNPs were confirmed, and their allele frequencies were determined. We also investigated haplotype frequencies and linkage disequilibrium (LD) coefficients for these SNPs in Caucasians. Four TNFRSF6 SNP pairs were found to be in strong LD. The TNRFSF6 SNPs are useful for linkage and loss of heterozygosity studies probing the role of Fas-mediated apoptosis in autoimmune diseases and malignancies.     

BRCA1基因单核苷酸多态性与广东汉族女性散发性乳腺癌易感相关性研究

目的探讨BRCA1基因启动子区rs799906位点和编码区rs799917位点单核苷酸多态性（single nucleotide polymorphism,SNP）与广东汉族女性散发性乳腺癌易感性的关系。方法利用Sequenom Mass Array iPLEX GOLD系统对107例散发性乳腺癌患者及93例健康对照者的BRCA1基因两个SNP位点（rs799906,rs799917）进行检测,并对检测结果进行χ2检验和非条件Logistic回归分析。结果 rs799906位点TT、TC和CC三种基因型在病例组和对照组的分布频率有差异（χ2=8.407,P=0.018）。相对TT基因型而言,TC杂合型能增加乳腺癌发生的危险性（OR=2.566;95%CI：1.101～5.983;P〈0.05）,但等位基因T和C的频率分布无显著差异（χ2=2.169,P=0.141）。rs799917位点CC、CT和TT三种基因型的频率和等位基因C和T的频率在病例组和对照组的分布均无显著性差异（χ2=3.994,P=0.136;χ2=0.903,P=0.342）。结论 BRCA1多态性位点rs799906TC杂合型与散发性乳腺癌发病风险有相关性;而rs799917位点多态性与散发性乳腺癌发病风险无相关性。     

8q24 rs13281615基因多态性与中国汉族女性乳腺癌患病风险及临床病理特征的关系

乳腺癌发病是多因素共同作用的结果.与家族性乳腺癌相比,大多数散发性乳腺癌的发生主要与低外显率基因的多态性有关.最近,Easton等[1]和Hunter等[2]的2项大规模的全基因组关联研究(GWAS)发现了几个新的乳腺癌易感基因位点.     

Identifying and counseling women at increased risk for breast cancer

Women at increased risk for breast cancer should be identified and counseled about options for risk reduction. Identifying such women is simplified with use of the National Cancer Institute Risk Assessment tool, a computer-based tool that incorporates information on 6 risk factors for estimating an individual's risk of developing breast cancer. However, the tool does not incorporate all known or possible risk factors and may underestimate risk, particularly among women with a complex family history of breast cancer for whom alternative models of risk assessment are more appropriate. Women found to have an increased risk of breast cancer should be counseled about options for management, including close surveillance, lifestyle modifications, chemoprevention with tamoxifen, enrollment in a breast cancer prevention clinical trial, and prophylactic mastectomy and/or oophorectomy. In the absence of consensus about which risk level is best suited to which option, decisions about risk reduction depend as much on an individual's priorities and risk aversion as on numerical risk estimates.     

Factor VII activating protease. Single nucleotide polymorphisms light the way

Factor VII activating protease (FSAP) is a circulating serine protease with high homology to fibrinolytic enzymes. A role in the regulation of coagulation and fibrinolysis is suspected based on in vitro studies demonstrating activation of FVII or pro-urokinase plasminogen activator (uPA). However, considering the paucity of any studies in animal models or any correlative studies in humans the role of FSAP in haemostasis remains unclear. In relation to vascular remodeling processes or inflammation it has been convincingly shown that FSAP interacts with growth factors as well as protease activated receptors (PAR). Against this sparse background there are a plethora of studies which have investigated the linkage of single nucleotide polymorphisms (SNP) in the FSAP gene (HABP2) to various diseases. The G534E SNP of FSAP is associated with a low proteolytic activity due to an amino acid exchange in the protease domain. This and other SNPs have been linked to carotid stenosis, stroke as well as thrombosis in the elderly and plaque calcification. These SNP analyses indicate an important role for FSAP in the regulation of the haemostasis system as well as fibroproliferative inflammatory processes.     

MR imaging in screening women at increased risk for breast cancer

Hereditary breast cancer accounts for 5% to 10% of the total breast cancer burden. Screening of this group of women has been done by palpation and conventional mammography until recently, but because of the age group, mammography has a limited value. MR mammography has been demonstrated to be a reliable imaging modality in this group of patients.     

单核苷酸多态性与血液肿瘤的研究进展

单核苷酸多态性(single nucleotide polymorphisms,SNPs)作为人体基因组单个核苷酸变异所导致的DNA序列多态性,是第3代分子遗传标志,它决定基因的功能单位和人群遗传变异的内在特征。SNPs反映了个体表型、疾病易感性以及对药物、环境等影响因素反应的差异。血液肿瘤是一种多基因遗传疾病,涉及到多个遗传易感基因的相互作用。本文拟就近年来SNPs在血液肿瘤研究领域的相关进展作一综述。