PTGS2 and neoplasm: Transcriptome analysis of primary human macrophages cultured under hypoxic conditions identified upregulation of angiogenic factors such as VEGF, cyclooxygenase 2 (COX-2), angiopoietin, and fibroblast growth factor (FGF) [109] Consistently, HIF-1α-deficient macrophages cocultured with tumor spheroids demonstrate enhanced M2-type polarization with attenuated pro-angiogenic properties [110].