BACKGROUND: Many methods are used to treat liver cancer. Among them, radiofrequency ablation (RFA) is a hot topic because of its advantages. This study was designed to determine the significance of blood alpha-fetoprotein mRNA (AFPmRNA) changes in patients with hepatocellular carcinoma (HCC) treated with RFA. METHODS: The AFPmRNA content in blood samples from HCC patients was determined by reverse transcriptase-polymerase chain reaction (RT-PCR) before RFA and 48 hours, 72 hours, 1 week and 2 weeks later. RESULTS: The blood of 183 patients was negative for AFPmRNA before RFA, but that of 62 of them was positive 72 hours later, then returned to negative after 2 weeks. The blood of 129 patients was positive for AFPmRNA before RFA, but that of 112 of them became negative 2 weeks later; 17 patients were still AFPmRNA positive 2 weeks after RFA. CONCLUSIONS: Blood AFPmRNA, which is increased temporarily after RFA, can be used as an objective index for the persistence and recurrence of HCC after RFA. BACKGROUND: Many methods are used to treat liver cancer. Among them, radiofrequency ablation (RFA) is a hot topic because of its advantages. This study was designed to determine the significance of blood alpha-fetoprotein mRNA (AFP mRNA) changes in patients with hepatocellular METHODS: The AFP mRNA content in blood samples from HCC patients was determined by reverse transcriptase-polymerase chain reaction (RT-PCR) before RFA and 48 hours, 72 hours, 1 week and 2 weeks later. RESULTS : The blood of 183 patients was negative for AFP mRNA before RFA, but that of 62 was it was positive 72 hours later, then returned to negative after 2 weeks. The blood of 129 patients was positive for AFP mRNA before RFA, but that of 112 of they became negative 2 weeks later; 17 patients were still AFP mRNA positive for 2 weeks after RFA. CONCLUSIONS: Blood AFP mRNA, which is more temporarily after RFA, can be used as an objective index for the persistence and recurrence of HCC a fter RFA.