HIF1A, identified as one of the transcription factors, has been found to play an essential role in oxygen homeostasis. This protein is a heterodimer composed of HIF-1beta subunit and one of three subunits(HIF- 1A, HIF-2A or HIF-3A). The activation of HIF1A is closely associated with a variety of tumors and oncogenic pathways. HIF1A consists of DNA binding domain(DBD domain), Dimerization domain and C-terminla regulatiory domains, including two transactivation domains(TAD), an oxygen-dependent degradation(ODD) domain, and inhibitory domains.