Publication: Study on BCR-ABL1 positive chronic myeloid leukaemia patients and its associations with clinical, laboratory, prognostic profile and outcome
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Date
2022
Authors
Shakri, Nabihah Mohd
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Abstract
Objectives: Molecular detection of the BCR-ABL1 has been an important diagnostic marker in defining CML cases. This study aims to determine the distribution of BCR-ABL1 fusion transcripts among our CML patients and the association of the major fusion transcripts with clinical, laboratory, prognostic profiles and outcome. Methods: Ninety-eight (98) patients diagnosed as CML with BCR-ABL1 detected using One-Step Multiplex RT-PCR were identified from Haematology records in HUSM and HRPZII from January 2010 until December 2021 and distribution of the different fusion transcripts were studied. This twelve-year cross-sectional study was conducted using data extracted from patients’ medical records. In patients with positive BCR-ABL1 expressing major fusion transcripts (95 patients), further data obtained were the demographic data (age, gender, and ethnicity), clinical presentation (presenting symptoms, spleen size, phase of the disease), laboratory data (white blood cell, haemoglobin, platelet, eosinophil and basophil count, blast count, bone marrow blast count, cytogenetic study), prognostic profile and outcome (Sokal score, complete haematological response, transformation and overall survival). Only 72 patients were included in the study of 3-year overall survival, whom had a follow-up of more than 3 years (diagnosed from 2010 until 2018). Results: Out of 98 patients, 56% had e14a2, and 41% had e13a2 fusion transcripts. The remaining 2 patients had e14a3 while 1 patient co-expressed e13a2 and e14a2. Among patients with major BCR-ABL1 transcript type (e13a2 and e14a2), e14a2 patients showed older median age (p=0.025) while WBC count was significantly higher in patients with e13a2 fusion transcripts (p=0.014). In addition, there were significantly more patients with blastic transformation in e13a2 groups (p=0.038). Other parameters compared showed no significant associations with either group. The median age at transformation in patients with blastic transformation of CML (n=19) was 26 years old, with a median latency period of 12 months. The blast cell lineages were myeloid 68.4%, followed by B-lymphoid 26.3%, and mixed phenotypic 5.3%. Conclusion: In our population, e14a2 was the more common BCR-ABL1 fusion transcript type among CML patients. The difference in fusion transcripts expression might influence some parameters, including older age patients who were associated with e14a2 fusion transcript. Meanwhile, patients exhibiting e13a2 might be associated with higher WBC count at diagnosis, and more vulnerable to blastic transformation of CML. Hence, every suspected CML patient should be tested for BCR-ABL1 gene fusion with the identification of the fusion transcript type, as these might influence their disease phenotype.
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Keywords
CML , fusion transcripts