Overexpression of HTRA1 promoted malignant phenotype of pancreatic tumor cells in vitro and pancreatitis-induced PDAC in KC mice, however, inhibiting HTRA1 blocked cell cycle at the G2/M phase, thereby inhibiting the malignant phenotype of tumor cells and promoting apoptosis in vitro, and inhibited the progression of PDAC in KC mice. This evidence concerns the gene HTRA1 and pancreatic neoplasm.