On the other hand, TAMs will also secrete chemokines including CCL20 and CCL18, induce the upregulation of matrix metalloproteinase 9 (MMP9) and vascular cell adhesion molecule 1 (VCAM-1) expression in pancreatic cancer cells, and enhance metastasis (21, 22). This evidence concerns the gene MMP9 and familial pancreatic carcinoma.