Multicellular model of signaling pathways in the tumor microenvironment. Schematic overview of intercellular and intracellular signal transduction in the pancreatic cancer cells and stellate cell. This model is composed of two pancreatic cancer cells (module A and C) and one stellate cell (module B). The suffix (a, b, c) in each node represents the cell (A, B, C) that a molecule belongs to. Blue nodes represent tumor-suppressor proteins, red nodes represent oncoproteins or lipids, arrows represent activation, and circle-headed arrows represent deactivation.