Epithelial-to-mesenchymal transition is a process by which epithelial cells acquire the characteristics of mesenchymal cells.28 Our group has proposed that EMT is an important pathway to VM formation.19,29 One study reported that STAT3 binds to the promoter of Hypoxia-Inducible Factor 1α (HIF-1α), indicating that p-STAT3 activation could regulate hypoxia-induced EMT.30 Another group of researchers came to a similar conclusion as ours that IL-6 induces STAT3 phosphorylation and further causes EMT changes in cancer cells.31 This evidence concerns the gene HIF1A and cancer.