VEGFA and cancer: Under hypoxic conditions, circ‐ZNF609 in EVs of ESCC elevates VEGFA (vascular endothelial growth factor A) by decreasing miR‐150‐5p levels and directly binds to HuR protein to inhibit the translation of ZO‐1, Occludin, and Claudin‐1 mRNA, thereby exacerbating cancer progression.141