Importantly, IL-33 secreted by gastric cancer tissue can activate ST2+ mast cells, which then release granulocyte-macrophage colony-stimulating factor (GM-CSF), monocyte chemoattractant protein-3 (MCP-3), and macrophage inflammatory proteins 1α and 1β (MIP-1α and MIP-1β). Here, CCL7 is linked to gastric cancer.