microRNAs as novel biomarkers for management of breast cancer

描述（由申请人提供）：乳腺癌（BrCa）是美国女性第二常见的癌症（除了皮肤癌），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，而是一种复杂的异质性疾病，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 （HER2）的激活状态是诊断和预后的主要因素，并决定了治疗的选择。不幸的是，一些属于相同ER/PR/HER2亚型的肿瘤会对治疗有反应，而另一些则不会。这表明存在未被发现的关键遗传和表观遗传差异，并可能导致治疗反应的高度可变性。因此，迫切需要确定信息丰富的分子生物标志物，以更好地管理每个患者的个体需求并指导治疗选择。本提案的重点是microRNAs （miR- NAs）作为BrCa管理的一类新型生物标志物的临床应用。mirna是短的非编码RNA基因，作为基因表达的转录后调节因子。mirna特定亚群的表达改变与不同类型的血液学和实体肿瘤有关，因此，mirna被认为是早期检测、诊断和/或预后的有希望的生物标志物。我们和其他人使用整个乳房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，体外研究揭示了mirna与BrCa中具有临床意义的蛋白质编码基因之间的机制相互作用；值得注意的是，特定的mirna参与了ER和HER2信号的调节。由于BrCa的大多数诊断和预后评估是使用基于形态学的检测方法在福尔马林固定石蜡包埋的组织切片上进行的，我们最近实施了一种基于荧光的灵敏方法，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分析：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局相关的标志物；ii)在我们机构的独立患者队列中验证鉴定的miRNA签名；iii)评估识别特征在不同辅助治疗环境中预测治疗反应的潜在效用，以无复发生存期为终点标记，在新辅助治疗环境中以病理完全缓解为终点标记。

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.