Exosome-encapsulated microRNA-4525, microRNA-451a and microRNA-21 in portal vein blood is a high-sensitive liquid biomarker for the selection of high-risk pancreatic ductal adenocarcinoma patients.

Background Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy with poor prognosis. This is due to late diagnosis and lack of reliable prognostic biomarkers. In this study, we focused on exosomal microRNA (miRNA) in portal vein blood (PVB) as a potential biomarker to identify patients at high-risk for recurrence and poor postoperative outcome. Methods Exosomal miR-4525, miR-451a and miR-21 expressions were assessed using PVB and peripheral blood (PB) collected from 55 PDAC patients during curative pancreatectomy. Correlation between the miRNA expressions and clinical outcomes, and target genes expressions was investigated. Results Exosomal miR-4525, miR-451a and miR-21 levels were upregulated in PVB, which were higher than those in the PB. High expression of miR-4525, miR-451a and miR-21 in PVB was associated with recurrence with a higher sensitivity, specificity, and accuracy than that in PB. Cox regression analysis showed miR-4525, miR-451a and miR-21 levels in PVB were independent prognostic factors for overall survival and disease-free survival. There was a negative correlation between the expressions of miR-4525 and MEN1 mRNA, miR-451a and CAB39 mRNA, and t miR-21 and PDCD4 mRNA. Conclusions miR-4525, miR-451a and miR-21 in PVB are potential biomarkers identifying patients at high-risk for recurrence and poor survival in resected PDAC patients.