Postoperative Prognosis Prediction of Pancreatic Cancer With Seven MicroRNAs

Objectives The aim of this study was to investigate microRNAs related to postoperative prognosis of pancreatic cancer by applying microarray analysis to stored surgical specimens. Methods We retrospectively analyzed the relationship between microRNA expression and postoperative survival of pancreatic cancer patients in Samsung Medical Center. After the correlation of microRNA expression between paraffin-embedded and fresh-frozen specimens was confirmed, we applied NanoString nCounter system to formalin fixed paraffin-embedded surgical specimens between 1995 September and 2010 June. Results Paired fresh and paraffin-embedded samples from 9 patients showed a high correlation (correlation coefficient > 0.91). Among 734 microRNAs, 7 microRNAs were found to be related to postoperative overall survival of 221 pancreatic cancer patients: hsa-miR-99a, hsa-miR-150, hsa-miR-194, hsa-miR-375, hsa-miR-664, hsa-miR-342-3p, and hsa-miR-487b (P < 0.01). The prognostic microRNA signature was consistent after adjustment of clinical parameters: resection status, stages, age, sex, adjuvant treatment, pathological differentiation and postoperative carbohydrate antigen 19-9 levels. Conclusions We found a prediction model for postoperative prognosis of pancreatic cancer using 7 microRNA expression patterns from archived formalin-fixed paraffin-embedded surgical specimens. The methods for microRNA detection and new microRNAs detected in this study provide new insights for new research of surgically resected pancreatic cancer samples and microRNAs.