HAS2 and neoplasm: The tumor microenvironment is characterized by an inflamed condition, due to both resident and immune cells’ release of a plethora of soluble factors, each able to alter HA production; HAS2 expression could be regulated by interleukin-1β [80], fibroblast growth factor-2 (FGF-2), PDGF, keratinocyte growth factor (KGF), and epidermal growth factor (EGF) [14] in non-cancer cells, while TGF-β exerts pleiotropic effects on both normal and tumor cells through autocrine and paracrine signaling mechanisms [81].