THE SIGNIFICANCE OF THE BCR::ABL1 BIOMARKER IN THE DIAGNOSIS AND TREATMENT MONITORING OF CHRONIC MYELOID LEUKEMIA: A NARRATIVE REVIEW

Julia Lenkiewicz; Marcin Trzciński; Oliwia Lenkiewicz; Agata Kotłowska; Zuzanna  Chmielewska; Wiktoria  Napiórkowska; Aleksandra Izabela Masłowska; Anna  Gwóźdź-Broczkowska; Gabriela Luba

doi:10.31435/ijitss.3(51).2026.6488

Authors

Julia Lenkiewicz Nicolaus Copernicus Hospital, Copernicus PL Sp. z o.o., Gdańsk, Poland https://orcid.org/0000-0002-6976-6990
Marcin Trzciński Nicolaus Copernicus Hospital, Copernicus PL Sp. z o.o., Gdańsk, Poland https://orcid.org/0000-0003-4817-7772
Oliwia Lenkiewicz Nicolaus Copernicus Hospital, Copernicus PL Sp. z o.o., Gdańsk, Poland https://orcid.org/0000-0002-4794-627X
Agata Kotłowska Nicolaus Copernicus Hospital, Copernicus PL Sp. z o.o., Gdańsk, Poland https://orcid.org/0000-0001-9665-8533
Zuzanna Chmielewska University Clinical Centre, Gdańsk, Poland https://orcid.org/0000-0003-1106-1119
Wiktoria Napiórkowska Military Institute of Medicine – National Research Institute, Szaserów 128, 04-141 Warsaw, Poland https://orcid.org/0009-0007-9546-3356
Aleksandra Izabela Masłowska Military Institute of Medicine – National Research Institute, Szaserów 128, 04-141 Warsaw, Poland https://orcid.org/0009-0006-7634-1006
Anna Gwóźdź-Broczkowska Military Institute of Medicine – National Research Institute, Szaserów 128, 04-141 Warsaw, Poland https://orcid.org/0009-0005-4839-5261
Gabriela Luba National Medical Institute of the Ministry of the Interior and Administration, Warsaw, Poland https://orcid.org/0009-0007-4262-2093

DOI:

https://doi.org/10.31435/ijitss.3(51).2026.6488

Keywords:

Chronic Myeloid Leukemia, BCR::ABL1, Molecular Monitoring, RT-qPCR, Tyrosine Kinase Inhibitors, Treatment-Free Remission

Abstract

Chronic myeloid leukemia is defined by the presence of the BCR::ABL1 fusion, which plays a central role in disease pathogenesis, diagnosis, treatment selection, and molecular monitoring. This narrative review aimed to summarize the current clinical significance of BCR::ABL1, with particular emphasis on diagnostic methods, assessment of response to tyrosine kinase inhibitors, mechanisms of resistance, and treatment-free remission. A literature search was conducted using PubMed and Google Scholar, focusing primarily on English-language guidelines, review articles, and clinically relevant studies published between 2015 and 2025, while also including earlier landmark publications. The review shows that cytogenetic analysis, fluorescence in situ hybridization, and reverse-transcription polymerase chain reaction provide complementary diagnostic information. Serial RT-qPCR measurement of BCR::ABL1 on the International Scale remains the standard method for assessing the depth and kinetics of molecular response. Interpretation should consider previous results, treatment adherence, dose modifications, assay variability, and the overall clinical context. Detection of kinase-domain mutations, particularly T315I, may explain treatment resistance and guide subsequent TKI selection. Targeted next-generation sequencing and digital PCR may improve the detection of resistant subclones and low-level residual disease, but their findings should not be used as isolated treatment criteria. Overall, accurate and standardized BCR::ABL1 monitoring remains essential for individualized CML management, while further research is needed to validate additional prognostic markers and improve prediction of treatment-free remission.

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