S100A9 and neoplasm: These factors stimulate myelopoiesis leading to upregulation of STAT3 target genes (B-cell lymphoma XL (BCL-XL), cyclin D1, MYC, survivin, S100 calcium binding protein A8 (S100A8) and S100A9) and signaling pathways (STAT6, STAT1, and NF-κB) allowing infiltration of MDSC to tumor sites [65].