SNAI1 and neoplasm: An in vivo study reported that the low level of expression of the EMT transcription factor, SNAIL1 in tumor cells, induced the M1 polarization of macrophages, whereas the higher level of expression of SNAIL1 in tumor cells elicited M2 polarization by SNAIL1-mediated production of the granulocyte-macrophage colony-stimulating factor (GM-CSF) [51].