Comprehensive analysis of BCR/ABL variants in chronic myeloid leukemia patients using multiplex RT-PCR.

BACKGROUND: A specific chromosomal abnormality, the Philadelphia chromosome (Ph), is present in 90 - 95% of patients with chronic myeloid leukemia (CML). This aberration results from a reciprocal translocation between chromosomes 9 and 22, creating a BCR/ABL fusion gene. The diagnosis of CML is based on the detection of BCR/ABL gene or Ph chromosome. Fusion proteins with different sizes are encoded depending on the breakpoint in the BCR gene. In general, 3 breakpoint cluster regions in the BCR gene have been described: major (M-bcr), minor (m-bcr), and micro (micro-bcr). The aim of this study was to search the BCR/ABL fusion gene in 60 Tunisian patients using multiplex reverse transcription polymerase chain reaction (RT-PCR) and compare our results with those of conventional cytogenetics.

METHODS: Bone marrow (BM) or peripheral blood (PB) samples, obtained at diagnosis, from 60 patients were analyzed by multiplex RT-PCR and conventional cytogenetics.

RESULTS: 45 patients examined were positive for some type of BCR/ABL rearrangement. The majority of the patients (97.77%) expressed one of the p210 BCR-ABL transcripts (63% with b3a2 and 36% with b2a2) while only one patient showed a rare e19a2 transcript.

CONCLUSIONS: Multiplex RT-PCR is a fast and reliable technique for improved detection of typical and atypical BCR/ABL transcripts.