It is overexpressed in many cancer types, including pancreatic cancer, colon cancer, lung cancer, ovary cancer, hepatocellular carcinoma, and GC.7–12 The expression of TMPRSS4 is associated with the epithelial to mesenchymal transition (EMT) and upregulates integrin-α5 to induce invasiveness.13, 14 Additionally, TMPRSS4 regulates urokinase-type plasminogen activator (uPA) via a dual mechanism through increasing the gene expression and processing of pro-uPA into its active form, which leads to an enhanced invasion.15 The gene discussed is PLAU; the disease is gastric cancer.