Previous reports indicated that EGFR phosphorylation is one of the most common events in pancreatic cancer progression, and we discovered that EGFR phosphorylation was downregulated in periostin-shRNA lentivirus-transfected SW1990 and BxPC-3 cells, whereas the total amount of EGFR was unchanged. The gene discussed is POSTN; the disease is pancreatic neoplasm.