Although the specific pathogenesis of hemangioma has not been fully elucidated, it is currently regarded as multifactorial condition involving vascular endothelial cell proliferation, uncontrolled angiogenesis, and abnormal cytokines/pathways under hypoxia induction, e.g., HIF-1α, VEGF, and PI3K/Akt. The gene discussed is HIF1A; the disease is hemangioma.