STAT3 and hepatocellular carcinoma: After phosphorylation by AKT at serine residue 21 (pS21-EZH2), EZH2 can promote the methylation and phosphorylation of STAT3, thereby enhancing STAT3 activity, activating STAT3 signal transduction [46], and forming a positive feedback loop of STAT3/circ-LRIG3, which ultimately promotes the proliferation, migration, and invasion of HCC cells, and reduces cell apoptosis [47].