In 12 samples from t(12;21)-positive patients at diagnosis, the levels of the TEL-AML1 fusion transcripts were found to vary up to 14-fold after normalization to beta2M.     ///    Rapid and sensitive minimal residual disease detection in acute leukemia by quantitative real-time RT-PCR exemplified by t(12;21) TEL-AML1 fusion transcript..     ///    "We then optimized PCR primers for the RQ-PCR system and, using the t(12;21)+ REH cell line in spiking experiments, found a linear detection of TEL-AML1 over at least five logs. "    ///    We initially determined the expression of the different alternatively spliced TEL-AML1 mRNAs found in t(12;21) breakpoint variants I and II.     ///    "Interestingly, in samples obtained from seven patients at diagnosis, during induction chemotherapy, or relapse, the level of TEL-AML1 in peripheral blood (PB) and bone marrow (BM) was found to differ only by threefold, suggesting that MRD may be evaluated in PB samples in most patients. "