Identification of Saliva Using MicroRNA Biomarkers for Forensic Purpose

In the forensic science community, microRNA (miRNA) profiling has started to be explored as an alternative tool for body fluid identification. Several origins of body fluid can be distinguished by measuring differential expression patterns of particular miRNAs. However, most of reported saliva miRNAs are nonoverlapping and debatable. The aim of this study was to develop a strategy of identifying saliva using miRNA biomarkers for forensic purpose. Eight miRNA candidates were selected to examine expression abundance in forensically relevant body fluids using hydrolysis probes quantitative real-time PCR (TaqMan qPCR). Results revealed that none of them was truly saliva specific, and only miR-200c-3p, miR-203a, and miR-205-5p were higher or more moderate expression in saliva. A stepwise strategy that combines each of three miRNAs with different body fluid-specific miRNAs was developed, and three miRNA combinations could effectively differentiate saliva from other body fluids.