Integrative Molecular Epidemiology of Human Cancer

我们正在研究炎症在结肠癌和肺癌的风险和分子发病机制中的作用。结肠癌：炎症性肠病（IBD）患者患结直肠癌的风险高于一般人群。全基因组关联研究已经确定并复制了几个与IBD风险相关的基因座，但目前尚不清楚这些基因座是否也与结肠癌风险相关。我们在两项研究中发现STAT3中的rs744166与结肠癌风险相关；然而，在TP53突变肿瘤中，观察到的方向相反，可能是由于突变p53抵消了这种作用。总之，这些数据表明STAT3位点与IBD和癌症都有关。了解这种变异的功能，或者与其相关的一个基因的识别和功能，可能会解释这种基因在自身免疫和癌症中的作用。此外，对该位点的分析，特别是在IBD人群中，可能有助于解决该SNP与癌症之间的关系（Ryan BM等人，cancer epidemiology）。， In Press, 2014)。我们已经发现，NCF4和先天免疫基因的种系变异与结直肠癌风险增加有关。慢性炎症与结直肠腺瘤和癌症的病因有关；然而，很少有关键的炎症基因介导这种关系已被确定。在这项研究中，我们调查了先天免疫基因的种系变异与结直肠癌风险的关系。我们的研究是基于从前列腺、肺、结直肠癌和卵巢癌（PLCO）癌症筛查试验中收集的样本分析。我们在719例腺瘤病例、481例癌症病例和719例对照中研究了20个关键先天免疫基因的196个标签单核苷酸多态性（snp）与晚期结直肠腺瘤和癌症风险的关系。经Bonferroni校正，位于NCF4上游的rs5995355的AG/GG基因型与结直肠癌风险增加相关[优势比(OR)=2.43；95%置信区间（CI）： 1.73-3.39；P0.0001]。对rs5995355在NCF4中的功能影响的进一步研究可能有助于阐明炎症与结直肠癌之间的机制联系（Ryan等，intj .）。癌症,2014)。我们正在研究先天免疫基因多态性与结直肠癌风险的假设。调节先天免疫和炎症的基因遗传变异可能增加结直肠肿瘤的风险。为了评估这种关联，我们在PLCO筛选试验中对451例结直肠癌病例、694例结直肠癌晚期腺瘤病例和696例欧洲血统对照进行了巢式病例对照研究。共评估了98个基因的935个标签snp。16个snp与结直肠肿瘤风险相关（P0.01），但经多次检验调整后，只有rs2838732 （ITGB2）与结直肠肿瘤风险呈正相关(OR（每T等位基因）=0.68；95% CI: 0.57 ~ 0.83， P=7.7 × 10(-5)；调整P = 0.07)。ITGB2编码整合素β链家族中的CD18蛋白。ITGB2与结直肠癌的相关性比与腺瘤的相关性强得多，但在验证研究中没有重复。吸烟状态显著改变ITGB2 rs2838732关联。在从不吸烟者和曾经吸烟者中，它与结直肠肿瘤呈负相关，但在当前吸烟者中没有发现相关。在BPI/LBP和MYD88中观察到其他显著的snp发现。虽然研究结果还有待验证，但我们的研究结果表明，炎症相关基因的遗传变异可能与结直肠肿瘤的发生风险有关（Chang et al., Carcinogenesis, 2014）。口服避孕药（OC）的使用、激素替代疗法（HRT）与女性肺癌风险之间的关系仍存在争议。我们对国际肺癌协会提供的6项病例对照研究进行了汇总分析。使用多变量无条件逻辑回归和元分析模型调查潜在关联。采用多项逻辑回归来调查不同组织学类型的肺癌风险。研究发现，使用激素替代疗法的人患肺癌的风险较低。单独雌激素和雌激素+黄体酮HRT均可降低风险。未观察到剂量-反应关系与使用OC/HRT的年数。卵巢癌患者的鳞状细胞癌以及激素替代疗法患者的腺癌和小细胞癌的风险降低最大（Pesatori et al., Br.J.）。癌症,2013)。我们的研究结果表明外源性激素在肺癌病因学中起保护作用。肺癌：LDCT用于肺癌筛查的出现可能会导致I期肺癌的检测增加。目前，这些患者主要只接受手术治疗，大约30%的患者会复发并死亡。可以识别辅助化疗获益的患者的生物标志物可以显著降低患者的发病率和死亡率。在此，我们试图建立一个基于炎症的I期肺癌预后分类器。我们对前瞻性纳入PLCO研究的548例欧美肺癌病例进行了回顾性分析。在研究开始时收集的血清样本中，使用超灵敏的电化学发光免疫分析法测量CRP、IL-6、IL-8、TNFalpha和il -1 β。IL-6和IL-8均与较短的生存期相关。此外，IL-6和IL-8的联合分类器与I期肺癌患者和吸烟年龄大于或等于30包年的I期患者的不良预后显著相关。总之，这些结果进一步支持炎症标志物与肺癌预后之间的关联，并提示血清IL-6/IL-8联合分类器可能是指导I期肺癌患者治疗决策的有用工具（Ryan BM等，J Thorac）。肿瘤学，In Press, 2014)。我们还与David Schrump合作研究食管癌的端粒酶变异。尽管端粒酶突变与几种慢性炎症性疾病和血液恶性肿瘤的发病机制有关，但在人类癌症中尚未完全表征端粒酶突变。本研究旨在研究端粒酶突变在食管癌中的频率和潜在的临床相关性。应用测序技术评价143例食管癌（EsC）患者肿瘤及邻近正常粘膜端粒酶逆转录酶（TERT）及端粒酶RNA组分（TERC）的突变状态。测序分析显示一个缺失涉及TERC （TERC del 341-360）和两个非同义TERT变体[A279T（2个纯合，9个杂合）；A1062T（4杂合）]。与健康献血者相比，EsC患者A279T变异的次要等位基因频率高5倍（p0.01）。与wtert相比，A279T减少了端粒长度，破坏了tert - brg -1- β -连环蛋白复合物的稳定，显著减少了β -连环蛋白，下调了癌细胞中的典型Wnt信号传导；这些现象与EsC细胞增殖减少、额外的细胞骨架蛋白消耗、趋化性受损、化学敏感性增加和致瘤性显著降低相吻合（Zhang Y等，PLoS ONE, 9:e101010, 2014）。

We are investigating the role of inflammation in the risk and molecular pathogenesis of colon and lung cancer. Colon Cancer: Patients with inflammatory bowel disease (IBD) have a higher risk of developing colorectal cancer than the general population. Genome-wide association studies have identified and replicated several loci associated with risk of IBD however it is currently unknown whether these loci are also associated with colon cancer risk. We found that rs744166 in STAT3 was associated with colon cancer risk in two studies; however, the direction of the observation was reversed in TP53 mutant tumors possibly due to a nullification of the effect by mutant p53. In conclusion, these data suggest that the STAT3 locus is associated with both IBD and cancer. Understanding the function of this variant, or the identification and function of one in linkage with it, could possibly explain the role of this gene in autoimmunity and cancer. Furthermore, an analysis of this locus, specifically in the population with IBD, could help to resolve the relationship between this SNP and cancer (Ryan BM, et al., Cancer Epidemiol., In Press, 2014). We have discovered that germline variation in NCF4, and innate immunity gene, is associated with an increased risk of colorectal cancer. Chronic inflammation has been implicated in the etiology of colorectal adenoma and cancer; however, few key inflammatory genes mediating this relationship have been identified. In this study, we investigated the association of germline variation in innate immunity genes in relation to the risk of colorectal neoplasia. Our study was based on the analysis of samples collected from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. We investigated the association between 196 tag single nucleotide polymorphisms (SNPs) in 20 key innate immunity genes with risk of advanced colorectal adenoma and cancer in 719 adenoma cases, 481 cancer cases and 719 controls. After Bonferroni correction, the AG/GG genotype of rs5995355, which is upstream of NCF4, was associated with an increased risk of colorectal cancer [odds ratios (OR)=2.43; 95% confidence intervals (CI): 1.73-3.39; P0.0001]. Additional studies on the functional consequences of rs5995355 in NCF4 may help to clarify the mechanistic link between inflammation and colorectal cancer (Ryan et al., Int.J.Cancer, 2014). We are investigating the hypothesis that innate immunity gene polymorphisms and the risk of colorectal neoplasia. Inherited variation in genes that regulate innate immunity and inflammation may contribute to colorectal neoplasia risk. To evaluate this association, we conducted a nested case-control study of 451 colorectal cancer cases, 694 colorectal advanced adenoma cases and 696 controls of European descent within the PLCO Screening Trial. A total of 935 tag SNPs in 98 genes were evaluated. Sixteen SNPs were associated with colorectal neoplasia risk at P0.01, but after adjustment for multiple testing, only rs2838732 (ITGB2) remained suggestively associated with colorectal neoplasia (OR(per T allele)=0.68; 95% CI: 0.57-0.83, P=7.7 x 10(-5); adjusted P=0.07). ITGB2 codes for the CD18 protein in the integrin beta chain family. The ITGB2 association was much stronger for colorectal cancer than for adenoma, but it did not replicate in the validation study. The ITGB2 rs2838732 association was significantly modified by smoking status. Among never and former smokers, it was inversely associated with colorectal neoplasia, but no association was seen among current smokers. Other notable findings were observed for SNPs in BPI/LBP and MYD88. Although the results need to be replicated, our findings suggest that genetic variation in inflammation-related genes may be related to the risk of colorectal neoplasia (Chang et al., Carcinogenesis, 2014). The association between oral contraceptive (OC) use, hormone replacement therapy (HRT) and lung cancer risk in women is still debated. We performed a pooled analysis of six case-control studies contributing to the International Lung Cancer Consortium. Potential associations were investigated with multivariable unconditional logistic regression and meta-analytic models. Multinomial logistic regressions were performed to investigate lung cancer risk across histologic types. A reduced lung cancer risk was found for OC and HRT ever users. Both oestrogen only and oestrogen+progestin HRT were associated with decreased risk. No dose-response relationship was observed with years of OC/HRT use. The greatest risk reduction was seen for squamous cell carcinoma in OC users and in both adenocarcinoma and small cell carcinoma in HRT users (Pesatori et al., Br.J.Cancer, 2013). Our findings suggest that exogenous hormones can play a protective role in lung cancer etiology. Lung Cancer: The advent of LDCT for lung cancer screening will likely lead to an increase in the detection of stage I lung cancer. Presently, these patients are primarily treated with surgery alone and approximately 30% will develop recurrence and die. Biomarkers that can identify patients for whom adjuvant chemotherapy would be a benefit could significantly reduce both patient morbidity and mortality. Herein, we sought to build a prognostic inflammatory-based classifier for stage I lung cancer. We performed a retrospective analysis of 548 European American lung cancer cases prospectively enrolled in the PLCO study. CRP, IL-6, IL-8, TNFalpha and IL-1beta were measured using an ultrasensitive electrochemiluminescence immunoassay in serum samples collected at the time of study entry. IL-6 and IL-8 were each associated with significantly shorter survival. Moreover, a combined classifier of IL-6 and IL-8 were significantly associated with poor outcome in stage I lung cancer patients and in stage I patients with greater than or equal to 30 pack-years of smoking. In conclusion, These results further support the association between inflammatory markers and lung cancer outcome and suggest that a combined serum IL-6/IL-8 classifier could be a useful tool for guiding therapeutic decisions in stage I lung cancer patients (Ryan BM, et al., J Thorac.Oncology, In Press, 2014). We are also collaborating with David Schrump to investigate telomerase variants in esophageal carcinoma. Although implicated in the pathogenesis of several chronic inflammatory disorders and hematologic malignancies, telomerase mutations have not been thoroughly characterized in human cancers. The present study was performed to examine the frequency and potential clinical relevance of telomerase mutations in esophageal carcinomas. Sequencing techniques were used to evaluate mutational status of telomerase reverse transcriptase (TERT) and telomerase RNA component (TERC) in neoplastic and adjacent normal mucosa from 143 esophageal cancer (EsC) patients. Sequencing analysis revealed one deletion involving TERC (TERC del 341-360), and two non-synonymous TERT variants [A279T (2 homozygous, 9 heterozygous); A1062T (4 heterozygous)]. The minor allele frequency of the A279T variant was five-fold higher in EsC patients compared to healthy blood donors (p0.01). Relative to wtTERT, A279T decreased telomere length, destabilized TERT-BRG-1-beta-catenin complex, markedly depleted beta-catenin, and down-regulated canonical Wnt signaling in cancer cells; these phenomena coincided with decreased proliferation, depletion of additional cytoskeletal proteins, impaired chemotaxis, increased chemosensitivity, and significantly decreased tumorigenicity of EsC cells (Zhang Y, et al., PLoS ONE, 9:e101010, 2014).