Human cancer cell lines secrete cytokines able to impair macrophage anti-tumor properties, i.e., IL-10, TGF-β, and PGE2 stimulate myelopoiesis, producing granulocyte and macrophage growth factors, i.e., M-CSF (CSF-1), GM-CSF (CSF-2), and G-CSF (CSF-3). This evidence concerns the gene CSF2 and cancer.