Metastatic cancer cells induce a proinflammatory response in osteoblasts that includes the release of IL-6, IL-8, monocyte chemoattractant protein-1 (MCP-1/CCL2), vascular endothelial growth factor (VEGF), and CXCL5, which further fuel osteoclastic differentiation as well as activity and drive cancer progression [84,85,86,87]. The gene discussed is CCL2; the disease is cancer.