ABSTRACT
Philadelphia Chromosome (BCR/ABL) BCR/ABL results from the t(9 ;22)(q34 ;q l 1) chromosomal abnormality and
is present in 90-95% of cases of CM L at the time of diagnosis. The remaining cases have variants of this abnormality, some of which are cryptic, meaning they cannot be detected by routine chromosomal analysis (CG). Variations in the breakpoint on the B CR (breakpoint cluster region) gene result in abnormal fusion proteins of different sizes: M -BCR, μ-BCR and m-BCR.
