BCRABL Initial Screen

The BCR-ABL fusion gene is detected in 95% of CML cases, in 25-30% of adult ALL and 2-5% of childhood ALL .The BCRABL fusion transcript is the result of the reciprocal translocation between the long arms of chromosome 9 and chromosome 22 - [t(9;22)]. The breakpoint in the ABL-gene is generally 5’ of the exon a2. The major breakpoint region (M-bcr) identified in the BCR gene, lies within a 5.8kb large fragment, spanning exons b1 to b5. The most common M-bcr fusion transcripts are b3a2 and b2a2 or a mixture of both, although some other less common transcripts are also identified, ie b2a3, b3a3 .