DNA Methylation as a Risk Factor for Cervical Neoplasia

描述（由申请人提供）：尽管已经充分确定了人乳头瘤病毒（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CIN 2 -3）风险中的中心作用，但大多数HPV感染自发消退，只有少数进展为宫颈癌。因此，基于HPV的筛查对于识别SCIN 2 -3女性的特异性通常较低。显然，HPV感染以外的因素也在宫颈癌的发病机制中发挥重要作用。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的功能丧失。几乎每种肿瘤类型似乎在多个基因中具有CpG超甲基化，并且不同肿瘤存在独特的超甲基化谱。我们假设异常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大于或等于CIN 2 -3的高风险女性的生物标志物。我们建议有效地解决我们的假设，进行额外的分析，在正在进行的国家癌症研究所资助的项目中收集的样本的子集，题为“评估宫颈癌筛查方法（伊娃）”，一项研究，旨在评估各种筛查策略检测大于或等于CIN 3。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。我们计划通过绘制大于或等于CIN 2 - 3（病例）和CIN 1或正常组织学（对照）女性之间12个或更多候选基因的CpG岛甲基化模式，来定义一组与大于或等于CIN 2 - 3（目标一）风险密切相关的基因。基于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方法（MethyLight）用于检测宫颈拭子样本中的高甲基化基因。在目标二中，我们将检查用于鉴定具有大于或等于CIN 2 -3的女性的高甲基化基因组的测试性能。最后（目标三），在HPV 16感染的女性中，我们将确定HPV 16基因组长控制区的CpG低甲基化是否与大于或等于CIN 2 -3的风险增加、E7 mRNA高水平和重复HPV 16阳性访视相关。这项研究的数据不仅有助于我们了解CpG甲基化在宫颈肿瘤发生中的作用，还有助于更好地设计未来的宫颈癌控制方案。

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.