Detection of Differentially Expressed microRNAs in Serum of Pancreatic Ductal Adenocarcinoma Patients: miR-196a Could Be a Potential Marker for Poor Prognosis

MicroRNAs (miRNAs) have long been established to remain stable in circulation, and dysregulated miRNAs in serum of tumor patients could potentially serve as novel biomarkers. To determine whether certain serum miRNAs could represent potential diagnostic and prognostic biomarkers for pancreatic ductal adenocarcinoma (PDAC). About 35 patients diagnosed with PDAC at different stages between August 2007 and January 2009 were enrolled in this study. Sera from 15 chronic pancreatitis (CP) patients and 15 healthy individuals were treated as controls. Quantitative real-time polymerase chain reaction assays specific to mature miRNAs were used to quantify the relative levels of those PDAC-associated serum miRNAs. Of the seven miRNAs detected, three were identified as differentially expressed in PDAC and control groups. miR-21 was able to distinguish PDAC patients from CP (p = 0.033) and healthy subjects (p = 0.001), whereas miR-155 and miR-196a were able to differentiate sera with sick pancreas (PDAC/CP) from normal pancreas (p = 0.0002 and 0.010, respectively). Serum miR-196a expression levels in unresectable PDAC (stages III and IV) patients were significantly higher than those in resectable (stages I and II) patients (p = 0.001). Furthermore, serum miR-196a expression level was found to have a potential value in predicting median survival time of PDAC patients (high-level miR-196a, 6.1 months, (95% CI, 4.49-7.72) versus low-level miR-196a, 12.00 months, (95% CI, 5.92-18.08), p = 0.007). Serum miR-196a could be a potential noninvasive marker for PDAC prognosis and selection of laparotomy.