Genetic Susceptibility And The Environment In Cancer Ris

摘要： 我们有一个关于遗传易感性与疾病风险相关的研究计划。我与流行病学分支机构中的许多PI合作，在他们对生殖、自身免疫和神经疾病的研究中增加了遗传易感性的衡量标准，而我自己的研究继续主要集中在膀胱癌和前列腺癌上。在过去的几年里，我的团队一直专注于DNA修复基因的多态，因为我们试图了解NIEHS环境基因组计划发现的DNA修复基因多态的风险和表型后果。大量的DNA修复基因(&gt；200)，加上大量的多态(平均每个基因85个)，提出了一个越来越令人生畏的问题，因为我们很少或根本没有关于多态的功能后果的信息，而且还没有技术来在病例对照研究中对数千个多态进行廉价的基因分型。我们正在采取两种方法来简化这个问题：1)我们一直致力于描述DNA修复基因的基因单倍型(变异等位基因的特定组合)和2)为了找到修复基因与表型的关联，我们正在使用单细胞凝胶电泳法(彗星试验)来测量从我们拥有完整基因(现在是单倍型)信息的大样本人群的细胞中DNA修复表型的比率。我们已经开始在现有的病例对照研究中应用我们新发现的单倍型信息，并计划进行一项关于前列腺癌的新的大型研究。此外，我们开始探索使用SELDI蛋白质组图谱作为了解疾病易感性的一种新的分子流行病学工具。 去年的进展： 单倍型发现：我们利用EGP从90个不同种族的样本中产生的基因型数据，对107个基因的单倍型进行了表征。我们发现，尽管基因有许多多态，但大多数只有几个单倍型，而且令人惊讶的是，几乎没有重组的证据。大多数基因的单倍型具有相互排斥的等位基因集，并在不同种族之间共享，这表明它们是10万年前人类迁出非洲之前古老进化瓶颈的结果。这些古老的单倍型代表了一种简单的基因多样性组织，使研究基因与疾病关联的基因分型要求减少了30倍。 人类群体DNA修复的表型测量：我们在我的实验室建立了彗星实验，能够测量单个细胞的DNA损伤水平。我们已经修改和扩展了这种方法，以测量细胞群体中的DNA修复速度。使用90人的永生化淋巴细胞作为EGP的一部分进行重新测序，我们正在表征过氧化氢和MMS损伤后的修复率。这两种暴露都会产生损伤，主要通过碱基切除修复途径修复。我们已经完成了对第一批65个人的刻画，并正在努力完成剩下的25个人。此外，我们与大卫·邓森合作，开发了分析彗星数据的新统计方法，并发表了一篇关于这些方法的论文，提交了一篇，还有一篇正在准备中。 前列腺癌研究：作为与北卡罗来纳大学和路易斯安那州立大学的1000万美元DOD联盟的一部分，我获得了资金，以研究DNA修复和激素代谢基因多态与种族和前列腺癌侵袭性的关系。该联盟的项目计划在未来3年招募2000名前列腺癌患者，其中一半是白人，一半是黑人。我是遗传易感性项目的派，是SELDI蛋白质组学项目的联合研究员，还有来自NIEHS的亚历克斯·梅里克和肯·托默，以及其他人。患者登记应于2004年2月开始。

Summary: We have an established program of research on genetic susceptibility in relation to disease risk. I collaborate with a number of PIs within the Epidemiology Branch to add measures of genetic susceptibility to their studies of reproductive, autoimmune, and neurologic diseases, while my own research continues to center primarily on bladder and prostate cancers. During the last few years my group has focused on DNA repair gene polymorphisms as we try to understand the risks and phenotypic consequences of the DNA repair gene polymorphisms that are being discovered by the NIEHS Environmental Genome Project. The large number of DNA repair genes (>200), coupled with the large number of polymorphisms (averaging >85 per gene) presents an increasingly daunting problem given that we have little or no information about the functional consequences of the polymorphisms, and do not yet have the technology to cheaply genotype thousands of polymorphisms in case-control studies. We are taking two approaches to simplify this problem: 1) we have been working to describe gene haplotypes (the specific combination of variant alleles) for DNA repair genes and 2) In order to find repair genotype-phenotype associations we are using single cell gel electrophoresis (the Comet assay) to measure rates of DNA repair phenotype in cells from a large sample of people where we have complete genotype (and now haplotype) information. We have started to apply our newly discovered haplotype information in our existing case-control studies, and are planning a new large study of prostate cancer. In addition, we are beginning to explore the use of SELDI proteomic profiling as a new molecular epidemiologic tool for understanding disease susceptibility. Last year's progress: Haplotype discovery: We characterized haplotypes in 107 genes using genotype data generated by the EGP from an ethnically diverse sample of 90 people. We find that although genes have many polymorphisms, most have only a few haplotypes and show surprisingly little evidence of recombination. The haplotypes of most genes have mutually exclusive sets of alleles and are shared across ethnic groups, suggesting that they are the consequence of ancient evolutionary bottlenecks prior to human migration out of Africa 100,000 years ago. These ancient haplotypes represent a simple organization to gene diversity that provides a 30-fold reduction in the genotyping requirements for studies of gene-disease association. Phenotypic measure of DNA repair in human populations: We have established the Comet assay in my laboratory to be able to measure levels of DNA damage in individual cells. We have adapted and extended this assay to measure rates of DNA repair in populations of cells. Using immortalized lymphocytes from the 90 people being resequenced as part of the EGP we are characterizing repair rates following damage with H2O2 and with MMS. Both exposures produce damage predominantly repaired via the base excision repair pathway. We have completed characterization of the first 65 individuals, and are working to finish the remaining 25. In addition, working in collaboration with David Dunson, we have developed new statistical methods for the analysis of Comet data and have one paper published, one submitted, and one in preparation on these methods. Prostate cancer study: I have obtained funding, as part of a $10M DOD Consortium with UNC and LSU to study DNA repair and hormone metabolism gene polymorphisms in relation ethnicity and prostate cancer aggressiveness. The Consortium project plans to enroll 2000 men with prostate cancer, half white, half black over the next 3 years. I am PI of the genetic susceptibility project and am a co-investigator, along with Alex Merrick and Ken Tomer from NIEHS, and others, on the SELDI proteomics project. Enrollment of patients should start in February 2004.