MDSCs influence the tumor microenvironment by producing several angiogenic factors and vascular-modulating enzymes, such as bombina variegata peptide 8 (Bv8, a homolog of endocrine gland-derived vascular endothelial growth factor) through G-CSF dependent STAT3 signaling, promoting angiogenesis and hematopoietic cell mobilization. The gene discussed is STAT3; the disease is neoplasm.