PTK2 and hepatocellular carcinoma: For the impacts to the IGF1R downstream integrin/FAK/Src signaling, IGF1R knockdown markedly inhibited PSPC1-induced integrin β4 and β1 expression in SK-Hep1 and PLC5 cells, respectively, as well as suppressed FAK and/or Src activation in both HCC cells (Figure 4D,E).