Objective:To search the marker of micrometastatic hepatocellular carcinoma (HCC).Methods:Peripheral blood samples were obtained from 65 patients with hepatocellular carcinoma,21 non HCC malignant tumors,22 chronic hepatitis B or cirrhosis,and 21 normal healthy volunteers.To identify hepatocellular carcinoma cells in peripheral blood, liver specific alpha fetoprotein(AFP)mRNA was amplified from total RNA extracted from whole blood by nested reverse transcription polymerase chain reaction (Nested RT PCR).Results:AFP mRNA was not detected in the normal healthy volunteers and patients with non HCC malignant tumors.The presence of AFP mRNA in patients with HCC(44/65,67.7%)was higher than those with chronic hepatitis B or cirrhosis(2/22,9.1%, P