Genetic Epidemiology

这个遗传流行病学项目的许多调查都来自于对癌症高风险家庭的观察或其他病因学研究。最近对来自费城和旧金山黑色素瘤诊所的718名非西班牙裔白人皮肤黑色素瘤患者的病例对照研究分析显示，在大部分时间使用防晒霜的易感人群中，黑色素瘤的风险略有下降，但不显著。年轻女性是最可能使用日光浴床的人群，而日光浴床的使用与患黑色素瘤的风险有关。那些使用美黑床的人更有可能在不经常暴露在阳光下的部位长黑色素瘤。这些观察结果可能有助于解释普通人群中年轻女性黑色素瘤发病率上升和分布变化的原因。在意大利东北部进行的183例黑色素瘤病例和179例对照病例的问卷调查数据、肿瘤和DNA研究显示，黑色素皮质素-1受体（MC1R）基因的种系变异与BRAF癌基因体细胞突变的黑色素瘤之间存在很强的相关性，这些患者的黑色素瘤发生在身体暴露在阳光下的区域，并且患有有限的慢性太阳损伤。我们在一个独立的人群中证实了这种关联。来自其他地中海人群的数据已被收集和协调，以扩大对黑色素瘤风险与若干风险因素（包括免疫相关基因）之间关系的分析。在这个联合样本中，我们确定了端粒相关基因在黑色素瘤病因学中的作用的暗示证据。此外，计划对地中海国家和适当对照的黑色素瘤病例进行全基因组关联研究。已收集黑色素瘤组织标本，并计划分析黑色素瘤病变与日晒、身体部位、痣数、易感基因和分子改变的关系。我们已经选择了一个由60个候选基因组成的小组，用于黑色素瘤的发展和进展，我们目前正在使用该基因小组测试从200个FFPE病变中提取的DNA。基于结果，我们可以将分析扩展到更大的黑色素瘤病变样本，以更准确地对该疾病进行分子分类。导致黑色素瘤发展的潜在途径之一包括失去对普通黑色素细胞痣的调节，这些黑色素细胞痣获得非典型或发育不良的特征，可以进一步发展为肿瘤。为了研究这一途径，我们目前正在意大利和西班牙收集来自同一受试者的正常皮肤、普通黑素细胞痣、发育不良痣、黑色素瘤和黑色素瘤转移瘤的多个组织样本。我们计划研究细胞周期中多个基因突变的表达和存在，以及一系列组织样本和种系DNA的转导途径，以探索黑色素瘤通过痣发展的机制。脊索瘤是一种罕见的原发性恶性骨肿瘤，主要发生在胚胎脊索干细胞未能正常退化的轴骨中。已经开展了一个扩大的项目，收集来自美国和加拿大各地散发性脊索瘤患者的个人和家族病史、颊细胞和肿瘤组织切片。该项目将收集多达400名在任何年龄和解剖部位被诊断患有脊索瘤的患者。利用从本研究中招募的100例散发性脊索瘤患者中提取的颊细胞DNA，我们评估了T基因的拷贝数变异（CNVs）和罕见序列变异，T基因是迄今为止唯一鉴定的脊索瘤易感基因。我们发现了与疾病风险相关的几种常见和罕见的T基因变异。我们的研究结果还表明，尽管种系T重复在脊索瘤家族中相当常见（44%），但在散发病例中极为罕见。我们的发现为T基因的遗传变异在家族性和散发性脊索瘤发病机制中的重要性提供了更多的证据。目前，我们正在使用全外显子组测序来鉴定无T重复脊索瘤家族以及散发性脊索瘤病例的其他易感基因。人们越来越认识到正常微生物组的改变在人类疾病中发挥作用。采用美国国立卫生研究院人类微生物组计划的方案，我们正在进行初步研究，以评估吸烟者和非吸烟者之间口腔微生物组的差异。试点研究正在与罗切斯特大学医学和牙科学院的研究人员合作进行。我们与耶鲁大学组织微阵列（TMA）核心设备合作，成功构建了波兰乳腺癌研究中收集的浸润性肿瘤的TMA。免疫组织化学（IHC）染色肿瘤（N=842）对18个参与激素生物合成、代谢和受体介导途径的分子标志物进行分析，表明乳腺癌的危险因素可能因分子亚型和以激素标志物共表达为特征的激素途径而异。除了对浸润性肿瘤的分析，我们也在评估乳腺癌病例中末端导管小叶单位（TDLUs）的形态和分子特征，TDLUs是乳腺癌产生的结构。我们发现，与管腔肿瘤相比，TDLU复旧在含有核心基底表型（CBP）肿瘤的乳房中明显不那么明显。我们正在开展多项国际合作，利用其他研究的材料来证实和扩展这些发现。我们还分析了150例波兰乳腺癌病例中正常TDLUs中ER、PR、CK5和EGFR的表达，发现靠近乳腺癌的TDLUs反映了场效应，而距离较远的TDLUs则显示了乳腺癌危险因素对高危乳腺组织的影响。除了固定组织中候选标记物的TMA分析外，我们还在波兰乳腺癌病例的肿瘤和邻近正常组织中进行了基因表达谱分析。我们发现，与胎次相关的分子变化在er阳性肿瘤的乳腺癌患者中得以保留，但在er阴性肿瘤患者中被破坏，这一发现可能部分解释了在这两种肿瘤亚型中观察到的胎次差异效应。我们目前正在分析表达谱数据，以确定TDLU对合和奇偶的分子特征。最近，我们在香港开展了一项新的基于组织的乳腺癌研究，我们计划从多达1000例乳腺癌病例中收集乳腺肿瘤和邻近正常组织，目的是确定与香港中国女性乳腺癌亚型的风险和临床因素相关的分子变化。我们正在继续开展血液恶性肿瘤的研究，使用瑞典相关登记数据来补充GEB的家庭研究。我们正在分析Waldenstrom巨球蛋白血症（WM）后的第二个肿瘤，并将瑞典的结果与SEER登记的结果进行比较。相关肿瘤的鉴定将为我们的基因研究提供信息。初步分析显示WM后实体瘤的风险显著增加。

Many of the investigations in this genetic epidemiology project arise from observations in families at high risk of cancer or in other etiologic studies. Recent analyses of a case-control study of 718 non-Hispanic white patients with cutaneous melanoma from melanoma clinics in Philadelphia and San Francisco showed modest, non-significant decreased risk of melanoma among susceptible individuals who used sunscreens most of the time. Young women were the individuals most likely to use tanning beds, and use was related to melanoma risk. Those who used tanning beds were more likely to have melanomas in sites not usually exposed to sun. These observations may help explain the increasing rates and changing distribution of melanoma among young women in the general population. Questionnaire data, tumor, and DNA from a case-control study of 183 incident melanoma cases and 179 controls conducted in North-Eastern Italy, showed a strong association between germline variants in the melanocortin-1 receptor (MC1R) gene and melanoma with somatic mutations in the BRAF oncogene, in subjects with melanoma arising on sun exposed areas of the body and with limited chronic solar damage. We confirmed this association in an independent population. Data from other Mediterranean populations have been collected and harmonized to extend the analyses of association between melanoma risk and several risk factors, also including immune-related genes. In this combined sample, we identified suggestive evidence for a role of telomere-related genes in the etiology of melanoma. Moreover, a genome-wide association study of melanoma cases from Mediterranean countries and appropriate controls is planned. Melanoma tissue specimens have been collected and analyses of melanoma lesions in relation to sun exposure, body site, nevi count, susceptibility genes and molecular alterations is planned. We have selected a panel of 60 candidate genes for melanoma development and progression and we are currently testing the DNA extracted from 200 FFPE lesions using this gene panel. Based on the results, we may extend the analyses to a larger sample of melanoma lesions for a more accurate molecular classification of the disease. One of the potential pathways that leads to the development of melanoma includes the loss of regulation of common melanocytic nevi, which acquire atypic or dysplastic characteristics that can further evolve in neoplasia. To study this pathway, we are currently collecting multiple tissue samples of normal skin, common melanocytic nevi, dysplastic nevi, melanoma and metastasis from melanoma from the same subjects from Italy and Spain. We are planning to study the expression and presence of mutations in multiple genes of the cell cycle, and transduction pathways in the serial tissue samples and germline DNA to explore the mechanisms involved in melanoma development through nevi. Chordoma is a rare primary malignant bone tumor that arises mainly in the axial skeleton from rests of embryonic notochordal stem cells that failed to undergo normal regression. An expanded project has been developed to collect personal and family medical history, buccal cells and slides of tumor tissue from sporadic chordoma patients from throughout the United States and Canada. The project will collect up to 400 patients diagnosed with chordoma at any age and anatomic site. Using buccal cell DNA extracted from 100 sporadic chordoma patients we have recruited in this study, we evaluated copy number variations (CNVs) and rare sequence variants in the T gene, which is the only susceptibility gene for chordoma identified so far. We identified several common and rare variants in the T gene that are related to disease risk. Our results also demonstrated that, although germline T duplication is fairly common in chordoma families (44%), it is extremely rare among sporadic cases. Our findings provide more evidence for the importance of genetic variations in the T gene in the pathogenesis of both familial and sporadic chordoma. Currently, we are using whole-exome sequencing to identify additional susceptibility genes in chordoma families without T duplication as well as sporadic chordoma cases.Alterations in the normal microbiome are increasingly recognized to play a role in human disease. Using protocols adapted from the NIH Human Microbiome Project, we are conducting pilot studies to evaluate differences in the oral microbiome between smokers and nonsmokers. Pilot studies are being conducted in collaboration with investigators from the School of Medicine and Dentistry, University of Rochester. We collaborated with Yale University Tissue Microarray (TMA) core facility and successfully built TMAs of invasive tumors collected from the Polish Breast Cancer Study. Analyses of immunohistochemically (IHC) stained tumors (N=842) for 18 molecular markers involved in hormone biosynthesis, metabolism, and receptor mediated pathways suggested that risk factors for breast cancer may vary by molecular subtypes and by hormone pathways characterized by co-expression of the hormonal markers. In addition to the analysis of invasive tumors, we are also evaluating the morphology and molecular characteristics of terminal duct lobular units (TDLUs), the structures from which breast cancers arise, in breast cancer cases. We found that TDLU involution was significantly less pronounced in breasts containing core basal phenotype (CBP) tumors as compared to luminal tumors. We are developing multiple international collaborations to confirm and extend these findings using materials from other studies. We have also analyzed ER, PR, CK5, and EGFR expression in normal TDLUs in 150 Polish breast cancer cases and found that TDLUs near breast cancers reflected field effects, whereas those at a distance demonstrated influences of breast cancer risk factors on at-risk breast tissue. In addition to TMA analyses of candidate markers in fixed tissues, we have conducted gene expression profiling analyses in both tumor and adjacent normal tissues from a subset of Polish breast cancer cases. We found that parity-related molecular changes were preserved in breast cancer patients with ER-positive tumors but disrupted in patients with ER-negative tumors, a finding that may partially account for the observed differential effect of parity in these two tumor subtypes. We are currently analyzing the expression profiling data to identify molecular signatures for TDLU involution and parity. Recently, we have developed a new tissue-based breast cancer study in Hong Kong, in which we plan to collect breast tumor and adjacent normal tissues from up to 1,000 breast cancer cases with the goal of identifying molecular changes that are related to risk and clinical factors for breast cancer subtypes among Chinese women in Hong Kong. We are continuing to conduct studies of hematologic malignancies using the Swedish linked registry data to complement the family studies in GEB. We are in the process of analyzing second tumors after Waldenstrom Macroglobulinemia (WM) and also comparing the Swedish results with those from the SEER registry. The identification of associated tumors will inform our genetic studies. Preliminary analyses show a significantly increased risk of solid tumors after WM.