Abstract: Objective To evaluate serum level of microRNA-21（miR-21） in normal persons and patients with different liver diseases,and to investigate its effect in the diagnosis of hepatocellular carcinoma（HCC）. Methods The serum level of miR-21 in healthy controls （n=25）,patients with chronic hepatitis B（CHB,n=25）, cirrhosis（n=25）,and HCC（n=25） were measured by real-time quantitative RT-PCR. The relationships between serum miR-21 levels and clinical pathological features of HCC were also investigated. Results The relative serum levels of miR-21 in normal controls,CHB and cirrhotic patients were（1.1±1.7）,（2.3±2.6） and （2.8±2.5）,respectively,all of which were significantly lower than that in HCC patients（22.6±4.4）,P<0.001;The relative serum levels of miR-21 in HCC patients one week and one month after surgery were（18.4±3.5） and （3.1±2.7）,respectively,significantly lower than that before operation（22.6±4.4）,P<0.001;Serum levels of miR-21 were correlated with tumor size,tumor thrombosis and HBV infection,but not with tumor numbers,tumor differentiation and serum AFP levels. Conclusions Serum levels of miR-21 is elevated in HCC patients and might be used as a potential biomarker for the early diagnosis of HCC.

Key words: Hepatocellular carcinoma, MicroRNA-21, Serum, Diagnosis