Whereas in pathological angiogenesis, including tumor angiogenesis, hypoxia and VEGF are central to the acquisition of the angiogenic switch, alternative mechanisms leading to hypoxia-inducible factor 1-alpha (HIF-1α)-activation without hypoxia might also belong to the repertoire of an angiogenic phenotype in tumors [12,53]. This evidence concerns the gene HIF1A and neoplasm.