GENETIC INVESTIGATION OF NPC AND HCC IN A CHINESE POPULATION

中国人群中鼻咽癌和肝癌的基因研究

• 批准号: 7592946
• 负责人: Cheryl Winkler
• 金额: $ 44.15万
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7592946
• 关键词: Aflatoxin B1; Aflatoxins; Africa; African; Alleles; Animal Feed; Animals; Antibodies; Area; Asia; Biological Markers; Cancer Etiology; Candidate Disease Gene; Capsid; Carcinogens; Carcinoma; Case-Control Studies; Cause of Death; Cessation of life; Chemicals; China; Chinese People; Chromosomes, Human, Pair 4; Chronic; Chronic Active Hepatitis; Cirrhosis; Clinical; Code; Consumption; Country; DNA; Data; Data Collection; Databases; Detection; Developed Countries; Developing Countries; Development; Diet; Dietary Factors; Disease; Enrollment; Environmental Carcinogens; Environmental Exposure; Environmental Risk Factor; Epstein-Barr Virus Infections; Exposure to; Family; Family Study; Far East; Fishes; Food; Food Preservatives; Gene Targeting; Genes; Genetic; Genomics; Genotype; Goals; HIV Infections; Haplotypes; Hepatitis B Virus; Hepatocarcinogenesis; Herb; High Prevalence; Human; Human Herpesvirus 4; Immunoglobulin A; In Vitro; Incidence; Infection; Investigation; Laboratories; Leukocytes; Liver; Malignant Neoplasms; Meat; Metabolic Biotransformation; Methods; Microsatellite Repeats; Modeling; Nasopharynx Carcinoma; Nitrates; Nitrosamines; Occupational; Other Genetics; Outcome; Oxidative Stress; Participant; Pathway interactions; Patients; Peripheral; Persons; Phase; Phase I Clinical Trials; Phase II Clinical Trials; Phorbol Esters; Plants; Plasma; Population; Prevalence; Primary carcinoma of the liver cells; Production; Province; Quality Control; Questionnaires; RNA Splicing; Rate; Records; Relative Risks; Reporting; Research; Risk; Risk Factors; Role; Sampling; Simian B disease; Single Nucleotide Polymorphism; Site; Source; Southeastern Asia; Study Subject; Surveys; Testing; Therapeutic; Tissues; Triad Acrylic Resin; United States; Upper arm; Variant; Viral; Virus; Virus Replication; Water; base; cancer risk; carcinogenesis; case control; cohort; design; dosage; gene discovery; gene environment interaction; gene interaction; genetic analysis; genome-wide linkage; improved; nitrate; repaired; sample collection; tobacco exposure; urinary

The NPC collaborative study has as its primary objective the discovery of genes and characterization of variant alleles associated with the development of NPC in a Chinese population. NPC is a leading cause of cancer deaths in the Cantonese population in China. Case-control studies have indicated a strong role for environmental factors, including food preservatives (carcinogenic nitrosamines), salt-preserved fish, and phorbol esters in herbs and plants that are commonly consumed among ethnic populations with the highest NPC rates. Familial aggregation of NPC and evidence of linkage have been observed in China and in other countries. Since chronic EBV replication, as evidenced by detection of immunoglobulin A (IgA) antibody against EBV viral capsid, and exposure to dietary factors are predictive of NPC but do not explain all of the disease, we have hypothesized that there may also be genetic factors contributing to the development of NPC. We have therefore developed a case-control study to investigate the genetic correlates of NPC in a highly impacted region of southern China. HCC is one of the most common cancers worldwide and a leading cause of death in many countries, especially in East Asia and sub-Saharan African. HCC is also increasing in developed countries. In the United States the incidence of HCC increased from 1.4 per 100,000 population for the period from 1976 to 1980 to 2.4 per 100,000 for the period from 1991 to 1995. Both aflatoxin B1 (AFB1) contamination and HBV infection are well-recognized risk factors for HCC. AFB1 is one of the most potent carcinogens to which humans are exposed. AFB1 has a wide distribution and high concentration in human and animal foods particularly in HCC endemic regions along the southeast seacoast. Among them Guangxi is a HCC high-risk region where both AFB1 contamination and HBV infection are common. In Southeast Asia and certain regions of Africa, aflatoxin consumption and infection by HBV are important factors giving rise to the extraordinarily high incidence rates (24.235.5/100 000) of HCC in these areas. HBV-induced chronic active hepatitis and cirrhosis constitute major factors in liver carcinogenesis. HBV is associated with 70-75% of all HCC cases in Asia, the continent with the highest prevalence of HBV. A synergistic effect of AFB1 and HBV in increasing risk for HCC has been reported in many studies. We hypothesize that if there is a host genetic effect on oxidative stress leading to the development of HCC, it would be most evident in a population exposed to environmental hepatocarcinogens where exposure and dosage is strong enough to manifest the genetic effects. Both animal and in vitro studies indicate that oxidative stress might contribute to the key pathways in either virus or chemical induced hepatocarcinogenesis. There is evidence for strong correlations between environmental carcinogens and oxidative stress in study participants with both HBV infection and exposures to environmental carcinogens, providing an opportunity to screen candidate genotypes/haplotypes for HCC risk in this unique population. We will be using a candidate gene approach selecting genes involved in oxidative repair pathways. For targeted genes, all SNPs within regulatory, splice sites or coding regions (both synonymous and nonsynonymous) will be selected and htSNPs added to capture >95% of the variation. Gene-gene and gene-environment interactions will be fully analyzed in this model. The findings will be further compared with a HBV outcome case-control study of subjects from northern China. Accomplishments: Completion of enrollment and data collection for the NPC study: Enrollment, data collection, and DNA extractions for the NPC study Phase I and Phase II of the NPC study have been completed. Family triads were enrolled for haplotype inference and for quality control assessment of the pilot. No Mendelian errors were observed within any of the family triads attesting to the fidelity of sample handling and genotyping. Phase II is a cross-sectional case-control study and included a questionnaire to capture environmental factors, including occupational, dietary and tobacco exposures. The completion of enrollment of Phase I and II participants (n=4000) and the addition of environmental exposure data provides adequate power to discover main effect genes and to test gene-environment interactions. Microsatellite survey of Chromosome 4 region implicated in family study: We have completed a microsatellite survey of the short arm of chromosome 4, a region implicated in a genome-wide linkage study to be associated with familial NPC, for association with non-familial NPC. Thirty-four microsatellite markers spanning 18 Mb on the short arm of chromosome 4 were genotyped in our Phase I cohort, to determine if specific alleles within this region: 1) were associated with a propensity to develop chronic EBV replication as evidenced by IgA antibodies against EBV VCA; or 2) were associated with NPC. Although we observed significant association for 14 alleles associated with either NPC or chronic immunoglobulin A production (IgA+) (P=0.001-0.03), these were not significant after applying a correction for multiple comparisons. The Phase II study triples patient enrollment and includes environmental covariates offering the potential to validate this and other genomic regions that influence onset of NPC. We are now using the Phase II study to confirm associations found in Phase I. Sample collection and biomarker status for the HCC study: DNA from HCC liver tissues from HBV-infected persons and peripheral leukocytes of HBV-infected controls, together with plasma and urinary biomarkers of HIV infection, aflatoxin exposure and oxidative stress have been completed. Candidate genes and SNPs have been selected for genotyping using the Illumina Goldengate platform. These include genes involved in carcinogenesis, biotransformation and oxidative damage repair pathways. SNPs were selected based on their putative or known function or because they were haplotype tagging All samples are from HCC patients and local controls from Guangxi Province, a HCC endemic area in China where both AFB1 contamination and HBV infection are well-recognized risk factors. A database of all laboratory and clinical records, including carcinogen (aflatoxin) and oxidative stress biomarkers, has been established

鼻咽癌合作研究的主要目标是发现与中国人群鼻咽癌发展相关的基因和变异等位基因的特征。鼻咽癌是中国广东人癌症死亡的主要原因。病例对照研究表明，环境因素发挥着重要作用，包括食品防腐剂（致癌亚硝胺）、盐腌鱼以及NPC发病率最高的族群中常见的草药和植物中的佛波酯。在中国和其他国家都观察到了 NPC 的家族聚集性和相关性的证据。由于通过检测抗 EBV 病毒衣壳的免疫球蛋白 A (IgA) 抗体证明，慢性 EBV 复制以及暴露于饮食因素可以预测 NPC，但不能解释所有疾病，因此我们假设也可能有遗传因素导致利于NPC的发展。因此，我们开展了一项病例对照研究，以调查中国南方受影响严重的地区鼻咽癌的遗传相关性。 HCC 是全世界最常见的癌症之一，也是许多国家（尤其是东亚和撒哈拉以南非洲国家）的主要原因。 HCC 在发达国家也在增加。在美国，肝癌的发病率从 1976 年至 1980 年期间的每 10 万人口 1.4 例增加到 1991 年至 1995 年期间的每 10 万人口 2.4 例。黄曲霉毒素 B1 (AFB1) 污染和 HBV 感染都是公认的肝癌危险因素。肝癌。 AFB1 是人类接触的最强致癌物之一。 AFB1在人类和动物食品中分布广泛且浓度较高，特别是在东南沿海HCC流行地区。其中广西是肝癌高发地区，AFB1污染和HBV感染均多见。在东南亚和非洲部分地区，黄曲霉毒素消耗和乙型肝炎病毒感染是导致这些地区肝癌发病率极高（24.235.5/10万）的重要因素。 HBV引起的慢性活动性肝炎和肝硬化是肝癌发生的主要因素。亚洲是 HBV 患病率最高的大陆，70-75% 的 HCC 病例与 HBV 相关。许多研究报道了 AFB1 和 HBV 在增加 HCC 风险方面的协同作用。我们假设，如果宿主遗传对氧化应激有导致 HCC 发展的影响，那么这种影响在暴露于环境肝癌物质的人群中最为明显，因为暴露和剂量足以体现遗传影响。动物和体外研究表明，氧化应激可能是病毒或化学物质诱导肝癌发生的关键途径。有证据表明，在感染 HBV 并暴露于环境致癌物的研究参与者中，环境致癌物与氧化应激之间存在很强的相关性，这为筛选这一独特人群中 HCC 风险的候选基因型/单倍型提供了机会。我们将使用候选基因方法来选择参与氧化修复途径的基因。对于目标基因，将选择调控区、剪接位点或编码区（同义和非同义）内的所有 SNP，并添加 htSNP 以捕获 > 95% 的变异。该模型将全面分析基因-基因和基因-环境的相互作用。研究结果将进一步与针对中国北方受试者的乙型肝炎结果病例对照研究进行比较。成就： 完成 NPC 研究的入组和数据收集： NPC 研究的入组、数据收集和 DNA 提取 NPC 研究的第一阶段和第二阶段已经完成。家庭三合会被招募用于单倍型推断和试点的质量控制评估。在任何家族三联体中都没有观察到孟德尔错误，这证明了样本处理和基因分型的保真度。第二阶段是一项横断面病例对照研究，包括一份调查问卷以获取环境因素，包括职业、饮食和烟草暴露。 I 期和 II 期参与者 (n=4000) 的注册完成以及环境暴露数据的添加为发现主效应基因和测试基因-环境相互作用提供了足够的动力。与家族研究有关的 4 号染色体区域的微卫星调查：我们已经完成了对 4 号染色体短臂的微卫星调查，该区域涉及与家族性 NPC 相关的全基因组连锁研究，以了解与非家族性 NPC 的关联。在我们的 I 期队列中，对 4 号染色体短臂上跨越 18 Mb 的 34 个微卫星标记进行了基因分型，以确定该区域内的特定等位基因是否：1) 与发展慢性 EBV 复制的倾向相关，如 IgA 抗体所证明的那样。 EBV VCA；或 2) 与 NPC 有关。尽管我们观察到 14 个等位基因与 NPC 或慢性免疫球蛋白 A 产生 (IgA+) 相关（P=0.001-0.03），但在应用多重比较校正后这些并不显着。 II 期研究使患者入组人数增加了两倍，并纳入了环境协变量，有可能验证该基因组区域以及影响 NPC 发病的其他基因组区域。我们现在正在使用 II 期研究来确认 I 期中发现的关联。HCC 研究的样本收集和生物标志物状态：来自 HBV 感染者的 HCC 肝组织和 HBV 感染对照的外周白细胞的 DNA，以及血浆和尿液HIV感染、黄曲霉毒素暴露和氧化应激的生物标志物已经完成。使用 Illumina Goldengate 平台选择候选基因和 SNP 进行基因分型。这些包括参与致癌、生物转化和氧化损伤修复途径的基因。 SNP 的选择基于其假定或已知的功能，或者因为它们是单倍型标记。所有样本均来自广西省的 HCC 患者和当地对照，广西省是中国 HCC 流行区，AFB1 污染和 HBV 感染都是公认的危险因素。已建立所有实验室和临床记录的数据库，包括致癌物（黄曲霉毒素）和氧化应激生物标志物