GPI and hepatocellular carcinoma: PHI not only catalyzes reactions during glycolysis, but also acts as a cytokine, inducing invasion and metastasis. PHI binds to its receptor, Mr 78,000 glycoprotein (gp78), and promotes MMP-2 secretion, adhesion, and motility for enhanced invasive ability through Matrigel by activating β1 integrins in HCC cell lines