The goal of the study was to examine the transcriptional profile of pancreatic tumors to identify molecular subtypes in order to develop validated clinically useful gene expression signature with the potential to guide therapy decision. Tissue was obtained by snap freezing in liquid nitrogen as soon as removed. All tissue samples were stored at -80C. Samples were embedded in OCT and a 4ug section was taken for H/E staining. After QC procedure to ensure high quality RNA (RIN>7) and confirm PDAC histology, 78 samples were subjected to microarray analysis. All patients signed an Institutional Review Board approved consent for bio-banking, clinical data extraction and molecular analysis. 85 samples (77 tumors, 3 normal and 5 pancreatitis) were compared to a mixed reference pool of 66 tumor samples to identify gene expression patterns.