PIGF and neoplasm: This hypoxic microenvironment triggers HIF-1α stabilization in tumor cells and the consequent release of pro-angiogenic factors, such as growth factors (VEGF, PDGF, PIGF, ANG-2), chemokines (CXCL8, CXCL12), cytokines (TNFα, IL1β, TGFβ), and metalloproteases (MMPs), which results in the sprouting of new vessels supporting cancer cells growth (102, 103).