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AIM: To investigate the expression of adenovirus-mediated human endostatin (Ad/hEndo) gene transfer and its effect on the growth of hepatocellular carcinoma (HCC) BEL-7402xenografted tumors.METHODS: Immunohistochemistry analysis with an anti endostatin antibody was preformed to detect endostatin protein expression in HCC BEL-7402 cells infected with Ad/hEndo. MTT assay was used to investigate the effects of Ad/hEndo on proliferation of human umbilical vein endothelial cells (HUVEC). Intra-tumoral injections of 1×109 pfu Ad/hEndo was given to treat BEL-7402 xenografted tumors in nude mice once weekly for 6 wk. Mice received injections of Ad/LacZ and DMEM were regarded as control groups. After intra-turmoral administration with Ad/hEndo, the endostatin mRNA expression in tumor tissue was analyzed by North blotting, and plasma endostatin levels were determined using enzyme-linked immunosorbent assay (ELTSA).RESULTS: High level expression of endostatin gene was detected in the infected HCC BEL-7402 cells. Ad/hEndo significantly inhibited HUVEC cell proliferation by 57.2％ at a multiplicity of infection (MOI) of 20. After 6-week treatment with Ad/hEndo, the growth of treated tumors was inhibited by 46.50％ compared to the Ad/ LacZ control group (t=2.729, P＜0.05) and by 48.56％ compared to the DMEM control group (t=2.485, P＜0.05). The ratio of mean tumor volume in treated animals to mean tumor volume in the control animals (T:C ratio) was less than 50％ after 24 d of treatment. Endostatin mRNA in tumor tissue was clearly demonstrated as a band of approximately 1.2 kb, which was the expected size of intact and functional endostatin.Plasma endostatin levels peaked at 87.52±8.34 ng/mL rnat d 3 after Ad/hEndo injection, which was significantly higher than the basal level (12.23±2.54 ng/mL). By d 7,plasma levels dropped to nearly half the peak level(40.34±4.80 ng/mL).CONCLUSION: Adenovirus-mediated human endostatin rngene can successfully express endogenous endostatin in vitro and in vivo, and significantly inhibit the growth of BEL-7402 xenografted liver tumors in nude mice.