Detection of a novel CBFB-MYH11 fusion transcript in acute myeloid leukemia M1 with inv(16)(p13q22)

Abstract Acute myeloid leukemia (AML) with an inv(16)(p13q22) or t(16;16)(p13;q22) chromosomal abnormalityrepresents one of the most common subtypes of de novo cases. These chromosomal rearrangementsresult in multiple CBFB- MYH11 fusion transcripts, with type-A being the most frequent. We here describe a unique case of de novo AML-M1, with inv(16)(p13q22), leading to an unusual CBFB- MYH11 fusion transcript, and der(7)t(7;11)(q31;q21). The fusion transcriptinvolves a CBFB exon 5 with a breakpointat nucleotide 754, an insertion of a 13-bp sequence of CBFB intron 5 at the fusionpoint, and the MYH11exon 27 with a breakpointat nucleotide 3464. To our knowledge, this CBFB- MYH11 fusion transcripthas never been reported previously. The clinical characteristics of the present case are in line with previous reports suggesting that rare CBFB- MYH11 fusion transcriptslead to aberrant characteristics such as an atypical cytomorphology and additional cytogenetic abnormalities.