 The fusion gene AML1/ETO is a molecular marker for monitoring minimal residual disease (MRD) in acute myeloid leukemia with the t(8;21)(q22;q22) translocation.     ///    Patients whose AML1/ETO transcripts decreased by more than 2?log at CR had higher RFS (P?=?0.02).     ///    Quantitative analysis showed that there was no trend where higher relapse rate occurred in patients with higher levels of AML1/ETO transcripts at diagnosis (P?>?0.05).     ///    An increase of AML1/ETO transcripts (0.5?log) at any time after CR indicated increased risk of relapse (P?=?0.002).     ///    "In the qualitative group, AML1/ETO in 71.88 and 95.45?% patients became negative at six and 24?months after CR, respectively. "    ///    Our study shows that both qualitative and quantitative detection of AML1/ETO have prognostic value in MRD monitoring.     ///    Negative or continuous low expression of AML1/ETO indicates increased disease-free survival..     ///    "Patients negative for AML1/ETO at 6-12?months and 12-18?months after CR had lower relapse rate (P?=?0.003 and 0.000), higher relapse-free survival (RFS) (P?=?0.000 and 0.000), and overall survival (P?=?0.001 and 0.000) than patients with positive AML1/ETO. "    ///    "At the checkpoints of 3 and 5/6?months after CR, patients with lower AML1/ETO copy numbers showed lower probability of relapse (P?=?0.039 and 0.004). "    ///    "To evaluate the dynamic variation and prognostic significance of AML1/ETO, bone marrow samples from 52 patients at different periods were examined qualitatively (32 patients) or quantitatively (20 patients) using nested RT-PCR and RQ-PCR, respectively. "