Tumor-associated microglia notably break into the tumor mass in response to chemo-attractive cytokines released by the tumor it-self such as monocyte chemotactic protein-3 (MCP-3), colony-stimulating factor 1 (CSF-1) and granulocyte-colony stimulatory factor (G-CSF) [65,66]. The gene discussed is CCL7; the disease is neoplasm.