Comprehensive analysis of CBFbeta-MYH11 fusion transcripts in acute myeloid leukemia by RT-PCR analysis

CBFbeta-MYH11 fusion transcripts are expressed in acute myeloid leukemias of the M4Eo subtype. Patients who express CBFbeta-MYH11 fusion transcripts respond favorably to high-dose chemotherapy and are generally spared allogeneic bone marrow transplantation. Hence it is important to identify this fusion in all patients with acute myeloid leukemia M4Eo leukemia. The fusion can be detected by cytogenetics, fluorescence in-situ hybridization (FISH), or by molecular analysis with RT-PCR. Multiple fusion transcripts arising as a result of various breakpoints in the CBFbeta and MYH11 have been identified. In this report we describe a comprehensive RT-PCR assay to identify all known fusion transcripts and provide an algorithm for molecular analysis of CBFbeta-MYH11 fusions from patient specimens. Further, identification of the fusion transcript by such an assay would help in the diagnosis and follow up of patients with cryptic inversion 16 translocations (such as patient 2 in this report) not detected by standard cytogenetics or FISH and for rational design of probes for quantitative analysis by real-time PCR.