Circulating exosomal microRNAs as novel detection biomarkers in pancreatic cancer

Abstract

Background Circulating exosomal microRNAs are reflective of the characteristics of the tumor, are valuable biomarkers in different types of tumors, and play important roles in tumor progression and metastasis. The purpose of this study was to investigate the circulating exosomal microRNAs miRNA-21 and miRNA-210 as novel biomarkers for patients with pancreatic cancer (PC).Methods Serum exosomal microRNAs were extracted from the serum of PC and chronic pancreatitis (CP) patients using an RNA Isolation kit. To identify the exosomes in the serum, we used transmission electron micrographs for the crystalline structure, western blotting, and NanoSight for exosomal markers and nanoparticle characterization. The relative expression levels of exosomal microRNAs were quantified using quantitative PCR and compared between PC and CP patients.Results A total of 40 serum samples (30 PC and 10 CP) were collected. The expression levels of both exosomal miRNA-21 and miRNA-210 were obviously higher in PC patients compared with those in CP patients (both P<0.001). However, no significant difference in the relative serum levels of free miR-21 and miR-210 was observed between these two groups (both P>0.05). Exosomal miRNA-21 and miRNA-210 were related to tumor stage, as well as other factors. The diagnostic of exosomal miRNA-21 and miRNA-210 levels was 83% and 85%, respectively. Furthermore, when combining the expression of exosomal miRNA with serum CA19-9, the accuracy increased to 90%.Conclusions We herein identified that the serum exosomal miRNAs miRNA-21 and miRNA-210 may be of value as potential biomarkers and therapeutic targets for the diagnosis and treatment of PC.