PTK2 and hepatocellular carcinoma: Experimental data suggest that matrix stiffness might modulate HCC cells proliferation, invasion, angiogenesis through several pathways including extracellular signal-regulated kinase (ERK), protein kinase B (PKB/Akt), signal transducer and activator of transcription 3 (STAT3), integrin β1/GSK-3β/β-catenin [41] β1-integrin/focal adhesion kinase (FAK) [42], and β1-integrin/phosphatidylinositol-3- kinase (PI3K)/Akt signaling pathways [43].