Aberrant DNA Methylation as a Biomarker of HSIL in Liquid-based Pap Tests

描述（由申请人提供）：在美国，目前使用巴氏涂片（Pap）检测宫颈癌的筛查项目旨在早期发现和治疗癌前高级鳞状上皮内病变（HSIL）。在每年超过350万在巴氏试验中有模棱两可或轻度细胞学异常的妇女中，近50万有潜在的HSIL。这些发现强调了单独使用巴氏试验检测HSIL的局限性。在不明确的非典型鳞状细胞病例中，检测致癌性HPV DNA并不是一种有效的分类检测方法，由于致癌性HPV的高患病率（bbb80 %），不能排除HSIL （ASC-H）和低级别SIL (LSIL)，因此，所有患有ASC-H和LSIL的女性都需要进行阴道镜检查。过度治疗的风险和与此管理策略相关的不必要费用强调需要额外的辅助检查来改善巴氏试验中HSIL的检测。肿瘤抑制基因（TSGs）的异常DNA启动子甲基化是一种表观遗传改变，有助于肿瘤的进展。TSGs的甲基化，如DAPK1和IGSF4，在50%的癌前HSIL和宫颈癌中被检测到。肿瘤特异性甲基化谱的鉴定以及基于pcr的敏感和特异性检测方法的可用性奠定了其作为分子生物标志物的潜在用途。本应用程序的总体目标是确定TSGs的异常DNA甲基化是否可以作为液体巴氏试验中HSIL的分子生物标志物，以提高HSIL的早期检测。本研究的具体目的是：1)为tsg开发一种定量甲基化特异性PCR （Q-MSP）检测方法，将HSIL与LSIL和阴性液体基巴氏试验区分出来；2)通过Q-MSP检测，确定伴有潜在HSIL的模糊和轻度异常液体基巴氏试验是否为tsg甲基化阳性。对于目标1，我们将使用实时定量PCR结合标准MSP方法和残液基巴氏试验来开发tsg的Q-MSP检测，包括DAPK1和IGSF4。对于目标2，我们将优化的Q-MSP检测应用于活检证实HSIL的ASC-H和LSIL残留液基巴氏试验，并使用统计方法分析检测性能。开发一种分子生物标志物，有助于在巴氏试验中检测HSIL，这给诊断和管理带来了挑战，为未来的临床试验奠定了基础，并可能对宫颈癌筛查产生重大影响。

DESCRIPTION (provided by applicant): In the United States, current screening programs for cervical cancer using the Papanicolaou (Pap) test are aimed at early detection and treatment of precancerous high-grade squamous intraepithelial lesions (HSIL). Of the greater than 3.5 million women who have equivocal or mild cytologic abnormalities on Pap tests each year, nearly 0.5 million have underlying HSIL. These findings highlight the limitations of the Pap test alone for the detection of HSIL. Testing for oncogenic HPV DNA is not an effective triage test in equivocal cases of atypical squamous cells, cannot exclude HSIL (ASC-H) and low-grade SIL (LSIL) due to the high prevalence of oncogenic HPV (>80%) and, as a result, all women with ASC-H and LSIL are referred to colposcopy. The risk of overtreatment and unnecessary costs related to this management strategy underscore the need for additional ancillary tests to improve the detection of HSIL in Pap tests. Aberrant DNA promoter methylation of tumor suppressor genes (TSGs) is an epigenetic alteration that contributes to tumor progression. Methylation of TSGs, such as DAPK1 and IGSF4, has been detected in >50% of precancerous HSIL and cervical cancers. Identification of tumor-specific methylation profiles and the availability of sensitive and specific PCR-based detection methods underlie its potential use as a molecular biomarker. The overall goal of this application is to determine if aberrant DNA methylation of TSGs can serve as a molecular biomarker of HSIL in liquid-based Pap tests to improve early detection of HSIL. The specific aims of this study are to 1) Develop a quantitative methylation-specific PCR (Q-MSP) assay for TSGs that distinguishes HSIL from LSIL and negative liquid-based Pap tests and 2) Determine if equivocal and mildly abnormal liquid-based Pap tests with underlying HSIL are positive forTSG methylation by the Q-MSP assay. For aim 1, we will use real-time quantitative PCR combined with standard MSP methods and residual liquid- based Pap tests to develop a Q-MSP assay for TSGs, including DAPK1 and IGSF4. For aim 2, we will apply the optimized Q-MSP assay to ASC-H and LSIL residual liquid-based Pap tests that have biopsy-confirmed HSIL and use statistical methods to analyze the assay performance. Development of a molecular biomarker that aids in the detection of HSIL in Pap tests that present diagnostic and management challenges forms the basis for future clinical trials and could have a major impact on cervical cancer screening.