Identification of a novel CBFB-MYH11 transcript: implications for RT-PCR diagnosis

The chromosome rearrangements inv(16)(p13q22) or t(16;16)(p13;q22) are present in approximately 10% of all cases with de novo acute myeloid leukemia and define a subgroup with a favorable prognosis. Both aberrations result in a CBFB-MYH11 fusion gene that can be detected by RT-PCR. To date, a total of 10 different in-frame CBFB-MYH11 fusion transcripts have been identified. A newly described transcript can not be amplified with the commonly used PCR primers since the MYH11 junction is located outside the amplified region (MYH11 cDNA position 2134). We describe here a robust two-step RT-PCR assay that reliably detects all known CBFB-MYH11 transcripts types, including the new variant. Because all previously established RT-PCR protocols may miss the new CBFB-MYH11 transcript, we propose to use the improved RT-PCR approach described here for the reliable detection of all known CBFB-MYH11 fusion transcripts.