HIFs are stabilized in low oxygen conditions and activate the transcription of various genes that help the cell adapt to hypoxia. For instance, HIF-1α and HIF-2α induce the expression of vascular endothelial growth factor (VEGF), which promotes new blood vessel formation to improve oxygen supply to the tumor. They also upregulate genes involved in altering metabolism, enhancing survival pathways, and facilitating invasion and metastasis.
