VEGFA and neoplasm: As a member of the bHLH/PAS transcription factor family, ARNT2 regulates the transcription of its target genes, including hypoxia-inducible factor 1α (HIF-1α), which can combine with ARNT2 to form a complex and initiate hypoxia/nutrient deprivation-induced vascular endothelial growth factor expression, thereby promoting tumor angiogenesis [9, 13].