Under physiological conditions, colony-stimulating factors (G-CSF, M-CSF, and GM-CSF) and transcription factors regulate the normal maturation of granulocytes, but the dysregulation resulting from tumor-secreted factors leads to the production of granulocytic (or polymorphonuclear) MDSCs (PMN-MDSCs) [103,104]. Here, CSF2 is linked to neoplasm.