The goal of this phase I application is to establish feasibility for a quantitative molecular diagnostics technology based on the detection of microRNA (miRNA) using readily available clinical samples. Molecular diagnostics assays offer the potential for more sensitive, more accurate, and more objective clinical judgments. For prostate cancer (PrCa), the gold standard for pathological diagnosis is cytopathological analysis of biopsy tissue. However, this approach fails to detect ~20% of patients with cancer. Since nearly 1,000,000 prostate biopsies are performed each year, nearly 200,000 men each year harbor tumors that escape detection. The pathology of cancer is accompanied by numerous changes in the genome and transcriptome. Thus, there is significant opportunity to develop nucleic acid assays that correlate the presence of biomarker signatures with disease diagnosis, prognosis, or staging. MicroRNAs comprise an exciting new class of small, regulatory biomolecules. Data to date suggests that as many as half of all genes may be regulated by miRNA. Over the past few years, scientists have demonstrated that miRNAs play important roles in processes as diverse as early development, cell proliferation and differentiation, apoptosis and fat metabolism, and oncogenesis. Indeed, tumor-associated, differentially expressed miRNAs, termed "oncomirs," have been found in more than a half dozen different cancers and the number of oncomirs is growing rapidly. In this phase I application, we will demonstrate the feasibility for an integrated technology for the isolation and quantification of miRNA from PrCa diagnostic samples. We will optimize procedures for the extraction and detection of miRNA from two different clinical sample matrices, both of which are accessible from the current PrCa patient workflow: 1) fixed and embedded biopsy tissue, and 2) nitrocellulose prints ("tissue prints") of prostate biopsies. We will compare the yields and representation of miRNA for both samples with corresponding frozen tissue controls to determine which sample offers the best combination of sensitivity and robustness. Last, we will integrate procedures for the extraction and quantification of miRNA to enable a streamlined method for miRNA detection. In phase II, we will refine and apply this technology using emerging miRNA biomarkers to develop a PrCa molecular diagnostics assay with superior sensitivity to the standard cytopathological prostate biopsy. The goal of this project is to improve cancer diagnostics by developing an integrated technology that will augment current pathology practices and result in more accurate cancer diagnoses. We will apply this technology to prostate cancer to give physicians additional molecular information that may overcome limitations of the direct observation of cancer cells by a pathologist. This should result in fewer missed tumors and may be able to reduce the number of ambiguous diagnoses. [unreadable] [unreadable] [unreadable]