Fig. 2.

The pancreatic cancer microenvironment participates in metastasis. The pancreatic cancer microenvironment influences every step of metastasis via multiple signaling pathways. (1) The pancreatic cancer microenvironment can stimulate angiogenesis by cytokines to favor cancer cell survival and proliferation. (2) Molecules from the pancreatic cancer microenvironment can induce lymphangiogenesis to establish a pathway for lymphatic metastasis. (3) The pancreatic cancer microenvironment can facilitate the epithelial-mesenchymal transition to cause cancer cells to enter lymphatic vessel. (4) The pancreatic cancer microenvironment can play important roles in invasion and migration to facilitate metastasis. (5) Factors and exosomes derived from the pancreatic cancer microenvironment can induce pre-metastatic niche formation in liver and lung. These molecules or exosomes can activate hepatic stellate cells (HSCs) in liver for desmoplasia