Typically, cells will undergo apoptosis under such conditions, but tumor cells are able to upregulate both hypoxia-inducible factor 1 alpha (HIF-1α) and hypoxia-inducible factor 2 alpha (HIF-2α), which synergistically leads to the transcription of VEGF and hence the creation of more blood vessels [55]. Here, EPAS1 is linked to neoplasm.