STX4 and hepatocellular carcinoma: For example, CD109 (a negative modulating factor of transforming growth factor β1 [TGF-β1] signaling [40, 41]), sodium bicarbonate cotransporter 3 (which participate in the reabsorption of Na+), myristoylated alanine-rich C-kinase substrate (which binds to actin), and syntaxin 4 (which mediates matrix metalloproteinase secretion via promoting vesicle docking to the plasma membrane [42, 43]), were upregulated in the highly metastatic HCC cell line.