(101CAP1003-2) Development of a miRNAome---Based Pipeline for Verification of Targeted Cancer Biomarkers in Body Fluids (I)

MicroRNAs (miRNAs) are small RNA molecules which negatively regulate gene expression and control a wide variety of biological processes such as cell proliferation and differentiation, organ development, and cell homeostasis. Aberrant expression of miRNAs has been observed in many cancer types. Numerous studies also demonstrate that certain miRNAs may function as oncogenes or tumor suppressors. To utilize miRNAs as potential biomarkers, our laboratory has established a quantitative RT-PCR (qRT-PCR) method to simultaneously detect the expression levels of multiple miRNAs in small amounts of RNA obtained from clinical samples. Using the qRT-PCR platform technology, we profiled 270 miRNAs in 19 normal and 30 tumor tissues from patients with oral squamous cell carcinoma (OSCC) and identified 49 differentially expressed miRNAs. Clustering analysis indicates that the expression pattern of these differentially expressed miRNAs has significant power to discriminate OSCC samples from normal tissues. Ideally, biomarkers should be easily accessible such that they can be sampled non-invasively. Recently, miRNAs were found to be present at substantial levels in body fluids such as plasma, salivary and urine. Circulating miRNAs are either actively secreted by living cells or passively released from necrotic cells. Notably, certain miRNAs have been detected at unusual levels in plasma and saliva from cancer patients. Due to their roles in cancer processes, their observed stability, as well as their amiability for multiplexed detection, miRNAs in body fluids appear to be excellent molecular constituents of a multi-marker panel for noninvasive cancer detection. OSCC is one of the leading causes of cancer death in Taiwan. Early detection is crucial to ensure timely intervention for a good prognosis. However, the heterogeneous nature of tumor tissue makes it difficult to use a single biomarker to detect all OSCC patients with high specificity and sensitivity. To overcome this difficulty, prediction models using various statistical strategies and scoring methods have been developed to identify combination of biomarkers that can correctly identify cancer patients. The marker panel approach has been successfully demonstrated in other cancer types to produce diagnostic test with sufficient discriminating power for early cancer detection. We propose to use the qRT-PCR miRNA detection platform to verify promising miRNA candidates in plasma and saliva as biomarkers for oral cancer. The candidate miRNA pool will include 27 miRNAs compiled from literature survey and 13 in-house discovered miRNAs. The cohort will include healthy subjects, subjects with precancer lesions and patients with early stage OSCC. Through this study, we expect to identify a small number of plasma or salivary microRNA biomarkers that can accurately detect early OSCC. Using the expression levels of these miRNAs, we will construct a molecular classifier that can reach a high accuracy in the detection of the early OSCC. The multiplexed miRNA qRT-PCR assay, combined with the classifier algorithm, can be developed into a simple and reliable qRT-PCR based diagnostic assay to offer an accurate and standardized detection tool for early stage OSCC.

Project ID:PC10106-0038
External Project ID:NSC101-2325-B182-013