Under hypoxic conditions, HIF-1α regulates a vast set of genes and pro-angiogenic factors both in tumor mass and vascular endothelial cells, including vascular endothelial growth factor (VEGF) (Forsythe et al., 1996), angiopoietin-2 (ANGPT-2) (Simon et al., 2008), stromal-derived factor-1α (SDF-1α) (Ceradini et al., 2004), stem cell factor (SCF) (Bosch-Marce et al., 2007), and platelet-derived growth factor-β (PDGF-β) (Kelly et al., 2003). Here, KITLG is linked to neoplasm.