BACKGROUND: The prognosis of hepatocellular carcinoma (HCC) is poor and its early diagnosis is of the utmost importance. This study aimed to investigate the values of glypican-3 (GPC-3) expression in the liver and sera and its gene transcription for diagnosis and monitoring of metastasis of HCC. METHODS: Liver GPC-3 was analyzed in HCC tissues from 36 patients by immunohistochemistry and Western blotting. GPC-3 mRNA from circulating peripheral blood mononuclear cells from 123 HCC patients or 246 patients with other diseases or 36 HCC tissues was amplified by RT-PCR, quantitative realtime PCR, and confirmed by DNA sequencing. Circulating GPC-3 level was detected by ELISA. RESULTS: The increasing expression of GPC-3 was observed from non-cancerous to cancerous tissues, with brown granule-like staining localized in tumor parts of atypical hyperplasia and HCC formation. The positive rate of GPC-3 was 80.6% in HCC, 41.7% in their paracancerous tissues, and none in distal cancerous tissues (P<0.001), with no significant difference in differentiation grade and tumor number except for size (Z=2.941, P=0.003). Serum GPC-3 was detected only in HCC (52.8%) and significant difference was found between GPC-3 and tumor size (χ2 =6.318, P=0.012) or HBV infection (χ2 =23.362, P<0.001). Circulating GPC-3 mRNA was detected in 70.7% of HCC tissues, with relation to TNM stage, periportal cancerous embolus, and extra-hepatic metastasis (P<0.001). The combination ofcirculating GPC-3, GPC-3 mRNA and alpha-fetoprotein is of complementary value for HCC diagnosis (94.3%). CONCLUSION: Both GPC-3 overexpression and GPC-3 mRNA abnormality could be used as markers for the diagnosis of HCC and monitoring its metastasis. BACKGROUND: The prognosis of hepatocellular carcinoma (HCC) is poor and its early diagnosis is of the utmost importance. This study aims to investigate the values ​​of glypican-3 (GPC-3) expression in the liver and sera and its gene transcription for diagnosis and monitoring of metastasis of HCC. METHODS: Liver GPC-3 was analyzed in HCC tissues from 36 patients by immunohistochemistry and Western blotting. GPC-3 mRNA from circulating peripheral blood mononuclear cells from 123 HCC patients or 246 patients with other diseases or 36 HCC Circulating GPC-3 level was detected by ELISA. RESULTS: The increasing expression of GPC-3 was observed from non-cancerous to cancerous tissues, with brown granule -like staining localized in tumor parts of atypical hyperplasia and HCC formation. The positive rate of GPC-3 was 80.6% in HCC, 41.7% in their paracancerous tissues, and none in distal cancerous tissues ( P <0.001), no significant difference in differentiation grade and tumor number except for size (Z = 2.941, P = 0.003). Serum GPC-3 was detected only in HCC and tumor size (χ2 = 6.318, P = 0.012) or HBV infection (χ2 = 23.362, P <0.001). Circulating GPC-3 mRNA was detected in 70.7% of HCC tissues, with relation to TNM stage, periportal cancerous embolus, and extra-hepatic metastasis (P <0.001). The combination ofcirculating GPC-3, GPC-3 mRNA and alpha-fetoprotein was complementary value for HCC diagnosis (94.3%). CONCLUSION: Both GPC-3 overexpression and GPC- could be used as markers for the diagnosis of HCC and monitoring its metastasis.