ARNT and neoplasm: Excess HIF-2α is known to promote angiogenesis and tumor invasion, for example, through upregulation of hypoxia-induced genes such as VEGF and erythropoietin by heterodimerizing with aryl hydrocarbon receptor nuclear translocator (ARNT) to form the transcription factor hypoxia-inducible factor 1 (HIF-1) [15,16].