EZH2 and hepatocellular carcinoma: The tumor heterogeneity in HCC indicates that pathological subtypes could be helpful in the subclassification of HCC in addition to tumor staging, where glutamine synthase (GS), glypican-3 (GPC-3), heat shock protein 70 (Hsp70), and enhancer of zeste homologue 2 (EZH2) are the common markers for HCC diagnosis [8].