HIF1A has a role as a master transcriptional monitor of the adaptive response to hypoxia. Under hypoxic conditions HIF1A activates the transcription of over 40 genes， including， erythropoietin， glucose transporters， glycolytic enzymes， vascular endothelial growth factor， and genes whose protein products increase oxygen release or facilitate metabolic adaptation to hypoxia. HIF1A functions as an essential role in embryonic vascularization， tumor angiogenesis and pathophysiology of ischemic disease.
