Background: Chronic myeloid leukemia (CML) is typically associated with the Philadelphia chromosome, resulting in the production of BCR-ABL fusion oncoprotein with upregulated tyrosine kinase activity. We aimed to evaluate a new flow cytometric immunobead assay to detect BCR-ABL protein in a group of patients with CML.

Methods: We enrolled 49 patients with CML, whose qRT-PCR and/or cytogenetic analysis of Philadelphia chromosome aberration was available, including tyrosine kinase inhibitors (TKIs)-naïve and (TKIs)-treated patients with various levels of response. Twenty Philadelphia-negative healthy individuals were also enrolled to obtain analytical negative controls. Peripheral blood samples were analyzed for BCR-ABL fusion protein by flow cytometry.

Results: The BCR-ABL fusion protein flow cytometric assay seemed efficacious to both diagnose the presence (P-value <0.0001) and distinguish the levels (P-value = 0) of the Philadelphia chromosome aberration. Groups of TKI-naïve and TKI-treated patients as well as levels of molecular/cytogenetic response to TKI-therapy were effectively discriminated (P-value <0.01). The receiver operating characteristic (ROC) curve analysis indicated the diagnostic value of the assay as excellent (AUC = 0.95, P-value = 0).

Conclusions: The evaluated BCR-ABL fusion protein assay might be useful for diagnosing and monitoring Philadelphia chromosome aberration.