Similar to HIF-1α, Wang et al. suggested that HIF-2α expression is significantly correlated with tumor size, lymph node involvement, and metastasis, and high expression of the protein is associated with poor overall survival in BC patients.308 Thus, HIF-2α could be a valuable biomarker of BC progression and patient survival.308 It may promote the migration and invasion of human BC MCF-7 cells under hypoxic conditions by potentiating the Notch3 pathway.309 Bai et al. revealed that the downregulation of HIF-2α suppresses the stemness of human BC MDA-MB-231 cells and promotes apoptosis.310. This evidence concerns the gene EPAS1 and breast cancer.