Detection of chromosome translocations by bead-based flow cytometry.

Chromosome translocations resulting in fusion genes have been implicated in leukemogenesis. The paradigm involves the fusion of the genes encoding BCR and ABL, leading to a constitutively active tyrosine kinase. The detection of BCR-ABL has been limited to fluorescence in situ hybridization analysis, reverse transcription-polymerase chain reaction, of mRNA, and Western blot of analysis downstream effectors in the BCR-ABL activated pathway. Here, we describe a novel immunoassay that directly measures levels of BCR-ABL fusion protein and its phosphorylation in peripheral blood plasma and cell lysates. This approach has the potential for widespread application in the detection and quantitation of other fusion genes involved in hematological malignancies.