MMP9 and esophageal squamous cell carcinoma: Xia et al. [45] showed a reduction in cell proliferation and invasion in esophageal squamous cell carcinoma overexpressing HTRA1 due to blockage of the nuclear factor-κB signaling pathway coupled to a decrease in the Ki-67, Bcl-2 (B-cell lymphoma 2), Bcl-xL (B-cell lymphoma-extra large), cyclin D1 and MMP-9 (matrix metalloproteinase 9) proteins.