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). This evidence concerns the gene CXCL12 and neoplasm.