Besides, as the tumor grows larger, the core becomes hypoxic, resulting in hypoxia-induced upregulation of pro-angiogenic factors such as vascular endothelial growth factor receptor (VEGFR) 1–3 and stabilization of hypoxia-inducible factor-1α (HIF-1α) activity [25, 26]. The gene discussed is HIF1A; the disease is neoplasm.