MicroRNA Expression Alterations in Duodenal Mucosa of Patients With IPMNs: Potential Diagnostic/Prognostic Biomarker

Abstract

Background: Diagnostic and prognostication of IPMNs represents a vexing and increasingly common clinical problem. Current diagnostic and prognostic approaches remain suboptimal. Our group has focused on field carcinogenesis detection for risk stratification (reviewed in Gastro 2011). We have noted that in the peri-ampullary duodenal biopsies, there are microarchitectural alterations as detectable by our novel optical technologies, low coherence enhanced backscattering spectroscopy and partial wave spectroscopy (Clin Cancer res 2007, Dis Biomarkers 2008, Cancer Res 2009). However, the biological basis of duodenal alterations has been LEBS (micro-architectural) alterations have been unexplored. MicroRNAs have been implicated in pancreatic carcinogenesis at both the initiation and progression phase. We wanted to compare the miRNA expression in duodenal mucosa in IPMN patients and control patients and correlate miRNA profile with the disease. Methods:We obtained endoscopic biopsies from patients with IPMNs undergoing endoscopic ultrasound for evaluation. Controls were age and gender matched. The RNA was recovered from formalin fixed paraffin embedded sections) using Ribopure kit (Ambion). The total RNA was then reverse transcribed using Taqman miRNA kit using Megaplex RT Primer set A (Applied Biosystems). The cDNA was then diluted and loaded into Taqman Low Density Array (TLDA) for miRNA (ABI). Real time RT-PCR was performed on ABI Prism 7900HT system. The data analysis was done using the SDS RQ manager and Data Assist software. Results: The comprehensive miRNA profiling of duodenal mucosal RNA from IPMN and control patients showed downregulation of 15 miRNAs and upregulation of miR-212, miR-130b and miR-100. Importantly, the miRNA reported to be upregulated in pancreatic cancer (miR-212 and MiR-100) were also seen to be upregulated in duodenal mucosa. Similarly, miR-24, which is the key regulator of p16, was also significantly modulated in the duodenal mucosa, thus underscoring the field effect for miRNA expression in pancreatic cancer. Conclusions: We report, herein, for the first time, that microRNA in the duodenal mucosa are dysregulated in patients harboring IPMNs when compared to matched controls. Importantly, these demonstrate important molecular alterations in extended field carcinogenesis of pancreas cancer. Future studies will be to develop prediction rules of duodenal microRNA with or without LEBS (microarchitectural biomarkers). The future goals are both for diagnostics and more significantly from a clinical perspective for prognosis/natural history.