PTEN and hepatocellular carcinoma: Several signaling pathways mediated by different modulators have been known to activate MMP-9 in invasion and metastasis of HCC cells, including focal adhesion kinase (FAK)/extracellular signal-regulated kinase (ERK) axis by epimorphin [36], NF-kappa B by interleukin 23 [37], PTEN/PI3K/AKT pathway by Bmi-1 [34].