Their ability to migrate toward tumor sites is mediated by chemokine receptors such as CXCR1, CXCR2, CXCR4, and CCR2, which respond to glioma-secreted signals such as IL-8, stromal cell-derived factor 1, and monocyte chemoattractant protein-1 (MCP-1).405,406 This glioma-tropic migration enables direct therapeutic intervention within the TME, significantly improving drug bioavailability and reducing systemic toxicity. The gene discussed is CXCR4; the disease is neoplasm.