These results suggest that the oncogenesis of both AP-2α and POSTN as well as POSTN and TGFβ1 is dependent on the presence of the other protein and support our findings that the POSTN/TGFβ1 positive feedback loop activated AP-2α expression and is a key mediator of the oncogenic effect of POSTN in HCC. The gene discussed is TGFB1; the disease is hepatocellular carcinoma.