Multiple cytokines expressed in the tumor microenvironment (TME), such as IL-4, IL-10, transforming growth factor β (TGF-β), tumor necrosis factor-α (TNF-α), CCL2, colony-stimulating factor 1 (CSF1), and vascular endothelial growth factor A (VEGFA), are known to regulate macrophage development, recruitment, differentiation, and/or M1/M2-like activation in cancer.4 The gene discussed is CSF1; the disease is neoplasm.