CSF2 and cancer: Vascular endothelial growth factor (VEGF), granulocyte macrophage colony-stimulating factor (GM-CSF), and granulocyte colony-stimulating factor (G-CSF) promote MDSC activity in cancer [11, 17] but Qian et al has proved that these factors do not involved in induction of MDSC [7], so additional factors are required for induction of MDSCs by HSCs.