MDSC proliferation in cancer is caused by various growth factors and cytokines, like Granulocyte–macrophage colony-stimulating factor (GM-CSF), IL-6, vascular endothelial growth factor (VEGF), and Granulocyte-colony stimulating factor (G-CSF) (Ostrand-Rosenberg and Sinha 2009). Here, CSF3 is linked to cancer.