DNA Methylation as a Risk Factor for Cervical Neoplasia

描述（由申请人提供）：虽然人乳头瘤病毒（HPV）在宫颈癌及其前体、宫颈上皮内瘤变II-III级或原位癌（大于或等于CIN2-3）风险中的核心作用已得到充分证实，但大多数HPV感染会自发消退，只有少数进展为宫颈癌。因此，基于 HPV 的筛查对于识别 SCIN2-3 女性的特异性通常较低。显然，HPV感染以外的因素在宫颈肿瘤的发病机制中也发挥着重要作用。在包括子宫颈癌在内的多种癌症中，已发现启动子区 CpG 岛甲基化导致某些关键基因功能丧失。几乎每种肿瘤类型似乎在多个基因中都存在 CpG 高甲基化，并且不同肿瘤存在独特的高甲基化谱。我们假设异常的 DNA 甲基化与宫颈肿瘤的风险相关，并且在常规筛查中获得的脱落细胞样本中检测到异常 DNA 甲基化可以作为识别具有大于或等于 CIN2-3 高风险的女性的生物标志物。我们建议通过对正在进行的 NCI 资助项目中收集的样本子集进行额外分析来有效地解决我们的假设，该项目名为“宫颈癌筛查方法（EVA）的评估”，该研究旨在评估用于检测大于或等于 CIN3 的各种筛查策略。访谈数据、细胞学和组织学以及 HPV 结果将可用于计划的研究。我们计划通过绘制 CIN2-3 大于或等于 CIN2-3 的女性（病例）和 CIN1 或组织学正常的女性（对照）之间 12 个或更多候选基因的 CpG 岛甲基化模式，定义一组与大于或等于 CIN2-3 的风险密切相关的基因（目标一）。根据病例和对照之间的甲基化模式，我们将设计一种高通量检测（MethyLight）来检测宫颈拭子样本中的高甲基化基因。在目标二中，我们将检查测试高甲基化基因组的性能，以识别 CIN2-3 大于或等于的女性。最后（目标三），在感染 HPV16 的女性中，我们将确定 HPV16 基因组长控制区的 CpG 低甲基化是否与大于或等于 CIN2-3、高水平 E7 mRNA 和重复 HPV16 阳性就诊的风险增加相关。拟议研究的数据不仅有助于我们了解 CpG 甲基化在宫颈肿瘤发展中的作用，而且有助于更好地设计未来的宫颈癌控制计划。

DESCRIPTION (provided by applicant): Although a central role of human papillomavirus (HPV) in risk for cervical cancer and its precursor, cervical intraepithelial neoplasia grades ll-lll or carcinoma in situ (greater than or equal to CIN2-3) has been well established, most of the HPV infections resolve spontaneously and only few progress to cervical cancer. Thus, an HPV-based screening usually suffers from a low specificity for identification of women with SCIN2-3. Clearly, factors other than HPV infection also play an important role in pathogenesis of cervical neoplasia. A loss of function of certain critical genes by methylation of CpG islands in promoter region has been found in a variety of cancers, including cancer of the cervix. Almost every tumor type appears to have CpG hypermethylation in multiple genes and a unique hypermethylation profile exists for different tumors. We hypothesize that aberrant DNA methylation is associated with risk of cervical neoplasia and its detection in the exfoliated cell sample obtained at the routine screening can serve as a biomarker for identification of women who are at high risk of greater than or equal to CIN2-3. We propose to efficiently address our hypotheses by performing additional analyses on a subset of samples collected in the ongoing NCI-funded project entitled "Evaluation of Cervical Cancer Screening Methods (EVA)," a study designed to evaluate a variety of screening strategies for detection of greater than or equal to CIN3. Interview data, cytology and histology, and HPV results will be available to the planned study. We plan to define a panel of genes that are closely related to risk of greater than or equal to CIN2-3 (Aim one) by mapping methylation patterns of CpG islands of the 12 or more candidate genes between women with greater than or equal to CIN2-3 (cases) and those with CIN1 or normal histology (controls). Based on the methylation patterns between the cases and controls, we will design a high throughput assay (MethyLight) for detecting the hypermethylated genes in cervical swab samples. In Aim two, we will examine performance of testing the panel of hypermethylated genes for identification of women with greater than or equal to CIN2-3. Lastly (Aim three), among women with HPV16 infection, we will determine whether CpG hypomethylation in the long control region of HPV16 genome is associated with an increased risk of greater than or equal to CIN2-3, high level of E7 mRNA, and repeated HPV16-positive visits. Data from the proposed study will not only shed light on our understanding of the role of CpG methylation in development of cervical neoplasia but also help to better design future cervical cancer control programs.