Objective    To detect the expression of Caveolin-1 in hepatitis B virus (HBV) related hepatocellular carcinoma (HCC) and determine the correlation between Caveolin-1 and HBV infection and HCC.     Methods    Immunohistochemical analyses were performed to detect the expression of Caveolin-1 in 40 tissue samples of HBV related HCC and 10 samples of non-related HCC

and their corresponding 50 paracarcinoma tissues. pcDNA3.1(+) Caveolin-1 eukaryotic expression vector was constructed and the recombinant plasmid was transiently transfected into HepG2.2.15 cells. The expression of pcDNA3.1(+) Caveolin-1 was detected by Western blotting. HBsAg expression of transfected cells were determined by ELISA.     Results    Immunohistochemical analyses results showed a lower expression of Caveolin-1 in 95% HBV-related HCC samples compared to their corresponding paracarcinoma samples (P0.05). Western blotting indicated that the recombinant plasmids was successfully transfected into HepG2.2.15 cells and Caveolin-1 was expressed. Using ELISA analysis we observed that the levels of HBsAg in  the supernatants of transfected HepG2.2.15 cells were reduced by 46.2% (48 h

P0.05) and 48.8% (72 h

P0.05) compared with the control one. And also a lower secretion of HBsAg was found in the transfected HepG2.2.15 cells (decreased by 41% for 48 h and 50% for 72 h

when compared with the non-transfected cells

P0.05).     Conclusion    Caveolin-1 is expressed at a low level in HBV induced HCC

while the overexpression of Caveolin-1 might down-regulate HBV HBsAg secretion.