HIF1A and breast carcinoma: For example, of the hypoxia-induced circRNAs in human umbilical venous endothelial cells (circZNF292, circAFF1, circTHSD1, circDENND4C, circSRSF4 and circFOXJ3), only circDENND4C expression is HIF1α-dependent in breast cancer cell lines after hypoxia induction, which sponges miR-200b and miR-200c to promote breast cancer cell glycolysis, migration and invasion [26, 27].