Brief report Multiplex reverse transcriptase–polymerase chain reaction screening in childhood acute myeloblastic leukemia

To determine the incidence of leukemiaspecific rearrangements, 60 cases of childhood acute myeloblastic leukemia and transient myeloproliferative disorder were screened with a novel multiplex reverse transcriptase–polymerase chain reaction (RT-PCR) assay, and the results were correlated with the cytogenetic findings. The RT-PCR assay detects 28 different fusion genes and more than 80 different fusion transcript variants. RNA was isolated from methanol/acetic acid–fixed cells that had been routinely prepared for cytogenetic analysis. Nine different fusion transcripts were found in 40% of the cases, whereas 78.3% of the cases had abnormal karyotypes. Two cases with a t(6;11) and an MLL/AF6 gene fusion were missed cytogenetically. Conversely, cytogenetic analysis revealed 10 other welldefined chromosome rearrangements. Although cytogenetic analysis reveals a much broader range of abnormalities, multiplex RT-PCR serves as quality control and provides the essential information for minimal residual disease studies. Moreover, discrepant findings lead to the detection of new rearrangements on the molecular genetic level. (Blood. 2001;97:805-808)