Pancreatic ductal adenocarcinoma (PDAC) is recognized for its lethality which is largely due to late clinical manifestation combined with rapid dissemination. In order to move forward the time of diagnosis, specific, sensitive and easily accessible markers are essential. MicroRNAs are an emerging class of molecules involved in tumorigenesis and metastasis. Additionally, they are disease specific and highly stable in blood, predestined to become a novel class of biomarkers.

96 patients were enrolled from 2009 to 2010: PDAC: n=53, pancreatitis: n=30, healthy control: n=13. RNA was isolated from serum samples of each patient using a modified TRIzol method and artificial miRNAs were spiked in at 5nM. MicroRNA-microarray was carried out by febit GmbH (Heidelberg, Germany) for 19 PDAC, 15 pancreatitis and 8 control samples. Significantly differentially expressed miRNAs were validated by quantitative reverse transcriptase PCR in all samples.

The following miRNAs were validated to be upregulated in PDAC vs. both pancreatitis and healthy controls: miR-190, −1246, −26a, −3152, −1265, −924, while miR-509-3-5p, −519c-5p, −501-3p, −548s-195* were downregulated. Using the validated miRNAs, PDAC was differentiated from pancreatitis with a sensitivity of 0.84 and specificity of 0.93.

This is the first investigation of circulating miRNAs as biomarkers for PDAC that has made use of microarrays to investigate global expression rather than employing qRT-PCR to focus on specific miRNAs. Thus, novel biomarker candidates have been identified. Further functional analysis of these miRNAs will uncover their significance and role in the progression of PDAC. (Supported by a grant from Foerderverein Peter Geiger e.V.).