Downregulation of miR-124 predicts poor prognosis in pancreatic ductal adenocarcinoma patients

Background and aims: miRNA-124 (miR-124) expression was known to be downregulated in patients with pancreatic ductal adenocarcinoma (PDAC). Downregulation of miR-124 was significantly associated with poor prognosis in patients with PDAC. Recent studies have shown that circulating miRNAs could be the potential biomarkers for invasive diagnostic as well as prognostic purposes. The purpose of the current study was to characterise the serum miR-124 levels and assess the clinical significance of serum miR-124 in patients with PDAC.Methods: Using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) assays, serum miR-124 levels were determined in serum from 126 patients with PDAC (53 resectable pancreatic cancer and 73 unresectable pancreatic cancer), 28 chronic pancreatitis patients and 47 healthy control individuals. The prognostic significance of miR-124 and other clinicopathological variables was determined using univariate and multivariate analyses.Results: Serum miR-124 levels were significantly decreased in patients with PDAC. Serum levels of miR-124 distinguished PDAC from chronic pancreatitis (P<0.001) and healthy control subjects (P<0.001). Low serum levels of miR-124 were significantly associated with lymph node metastasis, tumour node metastasis (TNM) stage and shorter survival time after surgery. In multivariate analysis, serum miR-124 (P=0.001, HR: 2.47, 95% CI: 1.25-4.05), high TNM stage (P = 0.001, HR = 3.24, 95% CI: 2.03-8.08) and lymph node metastasis (P = 0.015, HR = 1.66, 95% CI: 1.02-3.13) were significant predictors.Conclusions: Serum miR-124 levels have utility as diagnostic biomarkers in patients with PDAC. These findings suggest, for the first time, that serum miR-124 levels may have prognostic impact in patients with PDAC.