microRNAs as novel biomarkers for management of breast cancer

描述（由申请人提供）：乳腺癌（BrCa）是美国第二大流行癌症（除皮肤癌外），也是仅次于肺癌的第二大癌症相关死亡原因。BrCa不是一种单一的疾病，而是一组复杂而异质的疾病，具有不同的分子改变。雌激素受体（ER）、孕激素受体（PR）和人表皮生长因子受体样2（HER 2）的激活状态是主要的诊断和预后因素，并决定了治疗选择。不幸的是，一些肿瘤归因于相同的ER/PR/HER 2亚型将响应于治疗，而另一些则不会。这表明存在关键的未检测到的遗传和表观遗传差异，并可能导致治疗反应的高度变异性。因此，迫切需要鉴定信息分子生物标志物，其可以用于更好地管理每个患者的个体需求并指导治疗选择。该提案集中于microRNA（miR-NAs）作为用于BrCa管理的新型生物标志物的临床应用。miRNA是短的非编码RNA基因，其充当基因表达的转录后调节因子。miRNAs的特定亚群的表达改变与不同类型的血液肿瘤和实体瘤有关，因此，miRNAs被认为是早期检测、诊断和/或预后的有希望的生物标志物。我们和其他人已经使用整个乳腺组织活检作为表达谱分析的RNA来源，将一小部分miRNA与BrCa联系起来。独立地，体外研究已经揭示了miRNA和蛋白质编码基因之间的相互作用机制，其在BrCa中具有临床意义;值得注意的是，特异性miRNA参与了ER和HER 2信号传导的调节。由于大多数BrCa的诊断和预后评估是在福尔马林固定的石蜡包埋的组织切片上进行的，使用基于形态学的测定，我们最近实施了一种灵敏的基于荧光的方法，该方法使我们能够通过原位杂交（ISH）和免疫组织化学（IHC）在同一组织切片中共同检测miRNA表达，用于细胞类型共定位和功能研究。在这里，我们建议使用这种联合ISH/IHC测定：i）确定由NCI合作乳腺癌组织资源（CBCTR）设计的组织微阵列中的miRNA表达，以发现与疾病进展和疾病结果相关的标志物; ii）验证来自我们机构的独立患者队列中鉴定的miRNA标签; iii）评估鉴定的特征在使用无复发生存期作为终点标志物的不同辅助治疗环境中和在使用病理学完全反应作为终点标志物的新辅助治疗环境中预测治疗反应的潜在效用。 公共卫生相关性：MicroRNA是最近发现的一类短的非编码RNA基因，其迅速成为癌症生物学领域的新范式。在这项提案中，我们将研究microRNA作为疾病进展和结局风险评估指标以及治疗反应预测因子的临床效用。对于这些研究，我们将使用一种快速灵敏的基于荧光的方法，该方法与自动化临床免疫组织化学测定完全兼容。我们希望产生重要的新信息，可能对乳腺癌的管理产生很大的影响。我们的研究结果将为开发基于miRNA的临床检测方法提供坚实的基础，以帮助医生做出关于患者治疗的关键决策。

DESCRIPTION (provided by applicant): Breast cancer (BrCa) is the second most prevalent cancer (other than skin cancer) and the second most common cause of cancer-related death after lung cancer for women in the United States. BrCa is a not a single disease, but rather a complex and heterogeneous group of diseases with different molecular alterations. The activation status of the Estrogen Receptor (ER), Progesterone Receptor (PR) and Human Epidermal growth factor Receptor-like 2 (HER2) are the main diagnostic and prognostic factors and dictate treatment selection. Unfortunately, some tumors ascribed to the same ER/PR/HER2 subtype will respond to treatment while others will not. This indicates that key undetected genetic and epigenetic differ-ences exist and likely contribute to the high variability of treatment response. Thus, there is an urgent need to identify informative molecular biomarkers that can serve to better manage the individual needs of each patient and guide treatment selection. This proposal focuses on the clinical application of microRNAs (miR- NAs) as a novel class of biomarkers for BrCa management. MiRNAs are short non-coding RNA genes that act as post-transcriptional regulators of gene expression. Altered expression of specific subsets of miRNAs has been linked to different types of hematologic and solid tumors, and, consequently, miRNAs are being regarded as promising biomarkers for early detection, diagnosis and/or prognosis. We and others have linked a small subset of miRNAs to BrCa using whole breast tissue biopsies as RNA source for expression profiling analysis. Independently, in vitro studies have revealed mechanistic interactions between miRNAs and protein-encoding genes with clinical implications in BrCa; notably, specific miRNAs have been involved in the modulation of ER and HER2 signaling. Since most diagnostic and prognostic assessment for BrCa are conducted on formalin-fixed paraffin-embedded tissue sections using morphology-based assays, we have recently implemented a sensitive fluorescence-based method that will enable us to co-detect miRNA expression by in situ hybridization (ISH) and protein expression by immunohistochemistry (IHC) in the same tissue section for cell type co-localization and functional studies. Here, we propose to use this combined ISH/IHC assay: i) To determine miRNA expression in tissue microarrays which were designed by NCI Co-operative Breast Cancer Tissue Resources (CBCTR) to find marker associations with disease progression and disease outcome; ii) To validate identified miRNA signatures in an independent cohort of patients from our institution; iii) To assess the potential utility of identified signatures to predict treatment response in dif- ferent adjuvant therapy settings using recurrence-free survival as endpoint marker and in a neoadjuvant therapy setting using pathological complete response as endpoint marker. PUBLIC HEALTH RELEVANCE: MicroRNAs are a recently-discovered class of short non-coding RNA genes that rapidly emerged as a new paradigm in the field of cancer biology. In this proposal, we will investigate the clinical utility of microRNAs as indicators for risk assessment of disease progression and outcome, and predictors of treatment response. For these studies, we will use a quick and sensitive fluorescence-based method, which is fully compatible with automated clinical immunohistochemistry assays. We expect to generate important new information that could have a high impact with respect to management of breast cancer. Our results should provide a solid foundation to develop miRNA-based clinical assays to assist physicians in making crucial decisions with regards to treatment of patients.