Chronic Myeloid Leukemia May Be Associated With Several bcr-ab1 Transcripts

In the majority of Philadelphia (Phi-positive chronic myeloid leukemia (CML) patients, the c-ab/ gene is fused to the bcr gene, resulting in the transcription of an 8.5 kb chimeric bcr-ab/ mRNA. which is translated into a fusion protein. In about 50% of the Ph-positive acute lymphoid leukemias (ALL), the bcr-ab1 gene fusion is identical to CML, while in 50% an alternative fusion between these two genes occurs, in which the central bcr-sequences are absent. This results in transcription of a 7 kb bcr-ab1 mRNA, encoding a P190bc‘-ab’ fusion protein. Cloning and sequencing of the chimeric part of bcr-ab1 cDNAs from two