MMP9 and gastric cancer: We focused on the mRNA expression of MMP-2, MMP-9, urokinase plasminogen activator receptor (uPAR), urokinase plasminogen activator (uPA), and its inhibitor PAI-1 because their activation has been associated with peritoneal metastases in gastric cancer [37,38] and they are regulated by β-catenin as EMT-promoting effectors [20,39].