Fibrosis-related miRNAs as serum biomarkers for pancreatic ductal adenocarcinoma

We investigated whether serum microRNAs (miRNAs) could be diagnostic or prognostic markers in pancreatic ductal adenocarcinoma (PDAC). We first identified miRNAs showing altered expression in human pancreatic stellate cells (hPSCs) co-cultured with PDAC cells (Panc-1 and BxPC-3) as compared to hPSCs cultured alone. Among the miRNAs with altered expression, let-7d exhibited reduced expression in an analysis of The Cancer Genome Atlas data. Inhibition of let-7d resulted in enhanced expression of fibrosis-related genes. We extracted serum miRNA from 45 PDAC patients and 42 healthy controls and quantified expression let-7d using digital PCR. Based on the level of let-7d expression, we were able to distinguish between PDAC patients and controls. Additionally, reduced let-7d expression correlated with poor overall survival. Thus, fibrosis-related miRNAs may be serum biomarkers for PDAC.