HIF1A and neoplasm: HIF-1α also induces the expression of several other hypoxia-responsive genes and subsequently the production and release of chemoattractants and soluble factors, such as CSF1, TGF-β, and vascular endothelial growth factor (VEGF); these in turn regulate the differentiation and maturation of different immunosuppressive cell types, such as Tregs, TAMs, and MDSCs, at the tumor site, as well as the secretion of immunosuppressive factors, such as prostaglandin E2 and IL-10 [36,50].