CSF2 and neoplasm: Excessive levels of tumor-produced granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) cause the faulty myelopoiesis through downregulation of the transcription factor interferon regulatory factor 8 (IRF8) and alternatively activate these MDSC, equipping them with potent immunosuppressive activity [111,112,113].