Prior works have demonstrated that the hypoxia-inducible factor HIF1α can potentially induce the production of TWIST and SNAIL and promote epithelial interstitial transformation [34, 35], while HIF1α can promote extracellular matrix degradation by upregulating the expression of MMP2/MMP9, thus helping tumor cell metastasis [36, 37]. The gene discussed is MMP9; the disease is neoplasm.