Real-time quantitative miRNA PCR analysis of human plasma samples; circulating miRNAs miR-34a and miR-150 associated with colorectal cancer progression. Homo sapiens

Background: Screening for the early detection of colorectal cancer is important to improve patient survival. The aim of this study was to investigate the potential of circulating cell-free miRNAs as biomarkers of CRC, and their efficiency at delineating patients with polyps and benign adenomas from normal and cancer patient groups. Methods: The expression of 667 miRNAs was assessed in a discovery set of 48 plasma samples comprising normal, polyp, adenoma, and early and advanced cancer samples. Three miRNAs (miR-34a, miR-150, and miR-923) were further examined in a validation cohort of 97 subjects divided into the same five groups, and in an independent public dataset of 40 CRC samples and paired normal tissues. Results: High levels of circulating miR-34a and low miR-150 levels distinguished groups of patients with polyps from those with advanced cancer (AUC=0.904), and low circulating miR-150 levels separated patients with adenomas from those with advanced cancer (AUC=0.875). In addition, the altered expression of miR-34a and miR-150 in an independent public dataset of forty CRC samples and paired normal tissues was confirmed. Conclusion: We identified two circulating miRNAs capable of distinguishing patient groups with different diseases of the colon from each other, and patients with advanced cancer from benign disease groups. Overall design: qPCR miRNA expression profiling. Plasma samples from 48 donors comprising 8 normal, 8 polyp, 16 adenoma samples, 8 early stage cancer samples (stage I/II), and 8 advanced cancer samples (stage III/IV) were used. RNA was extracted from equal volumes of plasma from each donor.