Prognostic MicroRNAs in cancer tissue from patients operated for pancreatic cancer - Five MicroRNAs in a prognostic index

摘要

Background: The aim of the present study was to identify a panel of microRNAs (miRNAs) that can predict overall survival (OS) in non micro-dissected cancer tissues from patients operated for pancreatic cancer (PC). Methods: MiRNAs were purified from formalin-fixed paraffin embedded (FFPE) cancer tissue from 225 patients operated for PC. Only a few of those patients received adjuvant chemotherapy. Expressions of miRNAs were determined with the TaqMan MicroRNA Array v2.0. Two statistical methods, univariate selection and the Lasso (Least Absolute Shrinkage and Selection Operator) method, were applied in conjunction with the Cox proportional hazard model to relate miRNAs to OS. Results: High expression of miR-212 and miR-675 and low expression of miR-148a*, miR-187, and let-7g* predicted short OS independent of age, gender, calendar year of operation, KRAS mutation status, tumor stage, American Society of Anesthesiologists (ASA) score, localization (not miR-148a*), and differentiation of tumor. A prognostic index (PI) based on these five miRNAs was calculated for each patient. The median survival was 1.09 years (Confidence Interval [CI] 0.98-1.43) for PI>median PI compared to 2.23 years (CI 1.84-4.36) for PI