MicroRNA in Blood as an Early Biomarker of Breast Cancer

描述(申请人提供)：乳腺癌是美国女性中最常见的癌症，不包括非黑色素瘤皮肤癌。虽然乳房X光检查的使用提高了乳腺癌的存活率，但需要更好的方法来筛查早期发现，特别是在年轻女性中。血液中循环肿瘤标志物的分析在乳腺癌筛查中可能是有用的。MicroRNAs(MiR)是一种小的(长度为22-25个核苷酸)的非编码RNA，通过与其3‘非翻译区(UTR)结合，可以有效地减少靶信使RNA的翻译。MIR被认为有助于肿瘤的发生，因为它们既可以作为肿瘤抑制因子发挥作用，也可以作为癌基因发挥作用。与相应的正常组织相比，观察到成熟和/或前体miR序列的异常表达水平。其他研究表明，在血液中可以发现MIR，而且非常稳定。这些结果导致了一种假设，即血浆MIR水平可能有助于癌症的早期诊断。这项提案寻求获得试点资金，以确定乳腺癌患者血浆中与对照相比过高表达的候选生物标记物miRs，并建立其在血浆中定量的实验室分析方法。乳腺肿瘤、邻近组织和相应的血液可以从哥伦比亚大学医学中心看到的新诊断的乳腺癌病例中获得。这些资源将使我们能够确定血浆MIR作为乳腺癌早期检测的有前景的新生物标记物。有两个具体目标。目的1将比较20例乳腺癌患者和20名年龄和种族匹配的对照组血浆样本的全基因组miR表达谱。然后，将使用实时定量聚合酶链式反应(RT-qPCR)分析在病例中过度表达的前5-10个miRs以确认阵列数据，然后将分析石蜡切片乳腺肿瘤/配对的邻近组织以确定它们是否也在肿瘤中与邻近组织相比过度表达。在目标2中，RT-qPCRs将用于确认病例/对照血浆的差异，使用一组独立的100例病例和匹配的对照。这项初步研究将为筛选乳腺癌特异性MIR提供资源，建立定量检测血浆MIR的实验室方法，并证明我们可以在诊断时发现乳腺癌。我们的长期目标是使用从乳腺癌家庭登记参与者那里收集的血液，这是一个关于乳腺癌高危家庭的国际登记，在诊断之前可以在其中获得血液。在高危人群中早期发现乳腺癌的筛查方法的发展将导致更好的治疗和生存。 公共卫生相关性：这项初步研究将确定乳腺癌患者血浆中上调的miRs与对照相比，后者可能被用于乳腺癌早期诊断的筛查。开发用于在血浆中测量它们的实时分析以及乳腺癌病例和对照的试点数据，对于未来资助一项大型前瞻性研究将是至关重要的。

DESCRIPTION (provided by applicant): Breast cancer is the most frequently diagnosed cancer in U.S. women, excluding nonmelanoma skin cancers. While mammography use has enhanced breast cancer survival, better methods are needed for screening for early detection, especially in younger women. Analysis of blood for circulating tumor markers may be useful in breast cancer screening. MicroRNAs (miR) are small (22-25 nucleotides in length) noncoding RNAs that can effectively reduce the translation of target messenger RNAs by binding to their 3' untranslated region (UTR). miRs have been proposed to contribute to oncogenesis because they can function either as tumor suppressors or oncogenes. Abnormal levels of expression for mature and/or precursor miR sequences compared with the corresponding normal tissues have been observed. Other studies have demonstrated that miRs can be found in the blood and are highly stable. These results have lead to the hypothesis that plasma levels of miRs might be useful for early diagnosis of cancer. This proposal seeks to obtain pilot funding to identify candidate biomarker miRs overexpressed in plasma of breast cancer cases compared to controls and to establish the laboratory assays for their quantitation in plasma. Breast tumor, adjacent tissues, and the corresponding bloods are available from consenting, newly-diagnosed breast cancer cases seen at Columbia University Medical Center. These resources will enable us to identify plasma miRs as promising novel biomarkers for early detection of breast cancer. There are two specific aims. Aim 1 will compare whole genome miR expression profiles in 20 plasma samples from breast cancer cases and 20 age- and ethnicity-matched controls. The top 5-10 miRs overexpressed in cases will then be assayed using a real time quantitative PCR (RT-qPCR) assay to confirm the array data and then paraffin section breast tumor/paired adjacent tissues will be analyzed to determine if they are also overexpressed in tumor compared with adjacent tissues. In Aim 2 the RT-qPCRs will be used to confirm case/control plasma differences using an independent set of 100 cases and matched controls. This pilot study will provide the resources to select breast cancer-specific miRs, establish the laboratory assays for quantitation of miRs in plasma, and demonstrate that we can detect breast cancer at the time of diagnosis. Our long term goal is to use bloods collected from participants in the Breast Cancer Family Registry, an international registry of families at high risk for breast cancer in which bloods are available prior to diagnosis. The development of screening methods for the early detection of breast cancer in high risk populations will lead to better treatment and survival. PUBLIC HEALTH RELEVANCE: This pilot study will identify miRs upregulated in plasma of breast cancer cases compared to controls that can potentially be used to screen for early diagnosis of breast cancer. The development of real time assays for their measurement in plasma and pilot data on breast cancer cases and controls will be essential for future funding of a large prospective study.