Abstract

Discovering Circulating MicroRNA Biomarkers Using a Highly Controlled qPCR Workflow

Lihan Zhou, Co Founder/Chief Technology Officer, MiRXES Pte Ltd

MicroRNAs (miRNAs) are non-coding RNAs which modulate the translation of mRNAs into proteins. MiRNA regulations are prevalent over a wide spectrum of biological pathways and often conserved across species. In recent years, aberrant miRNA expressions were found to be associated with the onset, progression and recurrence of many diseases. Unlike the larger mRNA and DNA molecules, the micro size (~22 nt) confers circulating miRNAs extraordinary stability in biofluids, making them highly attractive candidate biomarkers for non-invasive disease diagnosis and prognosis. Conversely, such short nucleotide sequences have made sensitive and robust detection of miRNAs a major challenge, especially for low expression miRNAs in biofluids and FFPE tissues. This has resulted in widespread data inconsistency and irreproducibility, and hampered the clinical translation of many promising miRNA biomarkers. Among the many technologies, qPCR is widely considered as the most sensitive and specific method to detect miRNA. We have thus designed a highly controlled qPCR workflow that centred on a novel miRNA qPCR assay technology and incorporated multi-layered control measures to account for intra- and inter-batch variations across both sample pre-analytical and analytical steps. This robust and high-throughput workflow has enabled our group to discover high performance serum biomarkers (AUC>0.9) and validate them in blinded and cross-population clinical studies. Several case studies including gastric and breast cancers will be presented to illustrate the application of this new miRNA qPCR technology for the discovery of circulating miRNA biomarkers.