The α-fetoprotein promoter (AFP) is a representative one to activate an exogenous gene specifically in hepatocellular carcinoma (HCC) (Tamaoki, 2000) and has been applied to targeted gene therapy for HCC (Kanai et al, 1996; Mawatari et al, 1998; Hallenbeck et al, 1999). This evidence concerns the gene AFP and hepatocellular carcinoma.