Our results elucidated the incidence, lineage-specificity, and variant forms of TEL/AML1 fusion transcripts in childhood ALL.     ///    Detection and quantification of TEL/AML1 fusion transcripts by polymerase chain reaction in childhood acute lymphoblastic leukemia..     ///    "Since the percentage of other chromosomal translocations in childhood ALL is not more than 5%, TEL/AML1 transcript would be the most feasible clone-specific marker for these patients. "    ///    " We investigated TEL/AML1 fusion mRNA in 108 children with acute lymphoblastic leukemia (ALL) (86 B-lineage ALL, 15 T-ALL, two mixed lineage ALL, and five other phenotypes) using reverse transcriptase-polymerase chain reaction (RT-PCR). "    ///    "TEL/AML1 transcripts were found in 14 patients (13%) including three relapsed patients, and were unexceptionally limited to B-lineage ALL patients. "    ///    The reciprocal AML1/TEL transcripts were detected in 12 (86%) of the 14 cases expressing a TEL/AML1 transcript.     ///    The incidence of TEL/AML1 transcripts among B-lineage ALL was 16% (14/86).     ///    "In addition, our method could be a powerful tool for quantification of the TEL/AML1 transcript and for the detection of MRD.. "    ///    "To evaluate the amount of TEL/AML1 molecules for the quantification of a minimal residual disease (MRD), a plasmid vector which contained either a long TEL/AML1 PCR product (464 bp) or a short one (425 bp) was used as a competitor. "