Therefore, in the present study, we attempted to develop a HCC-specific gene therapy system by expressing a dominant negative mutant form of the PP2A catalytic subunit α (DN-PP2Acα) [13] under direct transcriptional control of the AFP enhancer/pgk promoter, and investigated the therapeutic effects of this system in HCC in vitro and in vivo. The gene discussed is PTPA; the disease is hepatocellular carcinoma.