RT-PCR diagnosis of patients with acute nonlymphocytic leukemia and inv(16)(p13q22) and identification of new alternative splicing in CBFB- MYH11 transcripts

Abstract

As acute nonlymphocytic leukemia (ANLL) with inv(16) (p13q22) or t(16;16)(p13;q22) has been shown to result from the fusion of transcription factor subunit core binding factor (CBFB) to a myosin heavy chain (MYH11), we sought to design methods to detect this rearrangement using reverse transcriptase-polymerase chain reaction (RT- PCR). In all of 27 inv(16)(p13q22) and four t(16;16)(p13;q22) cases tested, a chimeric CBFB-MYH11 transcript coding for an in-frame fusion protein was detected. In a more extensive RT-PCR analysis with different primer pairs, we detected a second new chimeric CBFB-MYH11 transcript in 10 of 11 patients tested. The CBFB-MYH11 reading frame of the second transcript was maintained in one patient but not in the others. We show that the different CBFB-MYH11 transcripts in one patient arise from alternative splicing. Translation of the transcript in which the CBFB-MYH11 reading frame is not maintained leads to a slightly truncated CBFB protein.

1 Molecular and cytogenetic abnormalities in acute myeloid leukaemia and myelodysplastic syndromes

“…Large follow-up series have not yet been reported. In analogy to the alternatively spliced AML1-ETO fusion transcripts, which may lead to truncated CBFo~ units, alternative splicing in the CBF[5 unit has also been identified (van der Reijden et al, 1995). In summary both inv(16) and t(8;21) are found in leukaemias with relatively good prognosis and both are associated with disturbances within the CBF transcription factor.…”

“…On 16p13 the smooth muscle myosin heavy chain gene is involved (MYHll) (Liu et al, 1993a;van der Reijden et al, 1993). On 16q22 the involved gene has been identified as the core binding factor-[5 gene…”

Acute myeloblastic leukemia (AML) with inv (16)(p13;q22) and the rare I type CBFβ-MYH11 transcript: report of two new cases

“…This rearrangement results in the disruption of the myosin heavy chain (MYH) gene at 16p13 and the core binding factor ␤ (CBF␤) gene at 16q22. 2 Until now, 10 different CBF␤-MYH11 transcripts have been reported [3][4][5][6] (A to J), but the frequency of each transcript is variable: 85% for the A type, 5% for each of the D and E types, other rearrangements being rare. Recently, a standardized RT-PCR technique, considered to be able to identify all CBF␤-MYH11 transcripts, has been reported.…”

Development of a biochip‐based assay integrated in a global strategy for identification of fusion transcripts in acute myeloid leukemia: a work flow for acute myeloid leukemia diagnosis

“…Moreover, three very rare alternative FT of AML1‐ETO with 46, 68 and 82 nucleotides insertion upstream the exon 2 of ETO are also described (Tighe & Calabi, 1994). In case of CBFβ‐MYH11 rearrangements, heterogeneity of breakpoints on both genes and alternative splicing result in 10 different CBFβ‐MYH11 FT (A–J subtypes) and some other variants (van der Reijden et al. , 1995; Shurtleff et al.…”