MicroRNAs encode the diversity between pancreatic head and body/tail cancers

Different clinical outcome has been found between pancreatic head cancer and pancreatic body/tail cancer. MicroRNAs (miRNAs) have been reported to play a potent functional role in the complex functional pathway networks controlling important cellular processes including tumor progression and invasion. To identify miRNA signatures that may encode a difference, microarrays comprising 887 human miRNAs in strictly matched early stage (I-II) pancreatic body/tail cancers and head cancers were performed and the results were further verified by qRT-PCR. We found remarkably down-regulated miR-501-3p and up-regulated miR-375 expressions in pancreatic body/tail cancer compared with head cancer. The recurrence rate was obviously lower in pancreatic body/tail cancer, and the down-regulation of miR-501-3p was significantly associated with low-risk of recurrence after curative surgery. By in vitro study, we provided first evidence that miR-501-3p could promote invasion of PDAC cells (Panc-1 and Colo357) possibly via decreasing the expression of E-Cadherin. Our results suggest that pancreatic body/tail cancer might be ‘less’ malignant than pancreatic head cancer and two miRNAs (miR-501-3p and -375) may encode this diversity.