CSF2 and breast cancer: Factors, such as granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF) (24-26), vascular endothelial growth factor (VEGF), PGE2, interleukin (ILs)s [IL-1 (27-29), IL-6, IL-13, IL-17, IL-20, IL-33, IL-34 (30-35)], macrophage migration inhibitory factor (MIF) (36), along with microRNAs (miRNAs/miRs), contribute to MDSC amplification and activation in BC (37).