CSF1 and neoplasm: Moreover, tumor cells secrete various cytokines and chemokines, such as granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF), macrophage colony-stimulating factor (M-CSF), IL-6, IL-10, and PGE2, to promote the expansion and recruitment of MDSCs from the bone marrow to the tumor site [87, 88].