AIM.To investigate the expression of metallothioneins(MTs),which were recently thought to have closerelationship with tumors,in human hepatocellularcarcinoma.METHODS:Histological specimens of 35 cases of primaryhuman hepatocellular carcinoma with para-neoplasticliver tissue and 5 cases of normal liver were stainedfor MTs with monoclonal mouse anti-MTs serum(E9)by the immunohistochemical ABC technique.RESULTS:MTs were stained in the 35 cases of HCC,including 6 cases negative(17.1%),23 weaklypositive(65.7 %),and 6 strongly positive(17.1%).But MTs were stained strongly positive in all the fivecases of normal liver and 35 cases of para-neoplasticliver tissue.The differences of MTs expression betweenHCC and normal liver tissue or para-neoplastic livertissue were highly significant(P<0.01).The rate ofMTs expression in HCC grade I was 100 percent,higher than that in grade Ⅱ(81%)and grade Ⅲand Ⅳ(78 %).But the differences were notsignificant(P>0.05).No obvious correlationsbetween MTs expression in HCC and tumor size,clinical stage or serum alpha fetoproteinconcentration were found(P>0.05).CONCLUSION:Decrease of MTs expression in HCC mayplay a role in carcinogenesis of HCC.HTs are stainedheterogenously in HCC.We can choose the anticanceragents according to the HTs concentration in HCC,whichmay improve the results of chemotherapy for HCC. AIM.To investigate the expression of metallothioneins(MTs),which were thought to to have closerelationship with tumors,in human hepatocellularcarcinoma.METHODS:Histological specimens of 35 cases of primaryhuman hepatocellular carcinoma with para-neoplasticliver tissue and 5 cases of normal liver were stainedfor MTs with monoclonal mouse anti-MTs serum(E9) by the immunohistochemical ABC technique.RESULTS:MTs were stained in the 35 cases of HCC, including 6 cases negative(17.1%),23weakly positive(65.7 %), and 6 strongly positive( 17.1%).But MTs were stained strongly positive in all the fivecases of normal liver and 35 cases of para-neoplastic liver tissue.The differences of MTs expression betweenHCC and normal liver tissue or para-neoplastic livertissue were highly significant (P<0.01). The rate of MTs expression in HCC grade I was 100 percent,higher than that in grade II(81%)and grade IIIand IV(78 %).But the differences were not significant (P>0.05).No obvious correlationsbetween MTs expr Ession in HCC and tumor size,clinical stage or serum alpha fetoproteinconcentration were found(P>0.05).CONCLUSION:Decrease of MTs expression in HCC mayplay a role in carcinogenesis of HCC.HTs are stainedheterogenously in HCC.We can choose the anticanceragents according to The HTs concentration in HCC, whichmay improve the results of chemotherapy for HCC.