MicroRNA expression profiles in pancreatic cystic tumors.

Abstract

e14579 Background: Short non-coding microRNAs (miRNAs) play a role in post-transcriptional gene regulation and can contribute to cancer development and progression. Expression profiles can distinguish between normal pancreas, chronic pancreatitis and pancreatic adenocarcinoma (PDAC) and may be able to correlate with disease progression from non-invasive precursor lesions to PDAC. We aimed to investigate the global miRNA expression profiles in pancreatic benign-cystic-tumours (BCT) compared with PDAC and carcinoma-ex-IPMN (CEI). Methods: Microarray analysis was conducted on 43 formalin-fixed paraffin-embedded (FFPE) pancreatic tumour surgical resection samples. These included 20 BCT, 9 CEI and 14 PDACs. The total RNA including the miRNA was isolated from the FFPE slides. Samples were analyzed with the Geniom Realtime Analyzer (febit gmbh, Germany) using the Geniom Biochip MPEA Homo sapiens. The probes are specific for all major mature miRNAs and miRNA* sequences in Sanger miRBase (version 13.0). Differential expression analysis was performed. We compared: BCT vs. CEI; BCT vs. PDAC, and CEI vs. PDAC. Certain miRNAs of interest were further investigated using quantitative real-time reverse-transcriptase polymerase chain reaction (RT- PCR). Results: There was a poor correlation in the intensity values between the BCT and PDAC groups. This led us to identify 20 significantly deregulated miRNAs in PDAC when compared to BCT. There were another 54 miRNAs found to be deregulated when we compared BCT to CEI and CEI to PDAC. Benign tumour subgroups were also analysed. Conclusions: There appear to be unique miRNA expression profiles in pancreatic cystic tumours and precursor lesions. In addition, 20 miRNAs have been identified which may be specific to PDAC. We aim to identify miRNAs for use as clinical biomarkers. No significant financial relationships to disclose.