Animal studies indicate two chemokines—C-X-C motif chemokine–ligand–8 (CXCL8/IL-8) and monocyte chemoattractant protein-1 (CCL2/MCP-1)—especially important in the formation and rupture of cerebral aneurysms [17,18,19]. The gene discussed is CCL2; the disease is brain aneurysm.