MiR-194-5p in Pancreatic Ductal Adenocarcinoma Peritoneal Washings is Associated with Peritoneal Recurrence and Overall Survival in Peritoneal Cytology-Negative Patients

Background: Peritoneal dissemination is one of the major recurrence patterns in patients with pancreatic ductal adenocarcinoma (PDAC) and is associated with poor prognosis. Here, we assessed the diagnostic potential of microRNA (miRNA) profiles in peritoneal washings for prediction of peritoneal dissemination in PDAC. Patients and Methods: From January 2016 to July 2017, peritoneal washings were obtained prospectively from 59 patients with PDAC undergoing surgery the Yokohama City University Hospital. MiRNA expression was evaluated by Agilent human miRNA microarray and quantitative reverse-transcription polymerase chain reaction. Results: Microarray analysis identified upregulated and downregulated miRNAs in peritoneal washings of patients with peritoneal dissemination. We validated four miRNAs (miR-141-3p, miR-194-3p, miR-194-5p, and miR-200c-3p) with high expression in peritoneal washings. The cumulative incidence rate of peritoneal recurrence in peritoneal cytology-negative patients in the miR-194-5p high group was significantly higher than that in the miR-194-5p low group (p = 0.002). Univariate and multivariate analyses revealed that high miR-194-5p was associated with overall survival (OS). Conclusions: High expression of miR-194-5p in peritoneal washings is associated with peritoneal recurrence and poor OS in patients with peritoneal cytology-negative PDAC.