pubmed > ABL1 > bcr-abl1 transcripts

Philadelphia chromosome-positive B-cell acute lymphoblastic leukemia with e1a3 BCR-ABL1 transcript in a Nigerian with sickle cell anemia: a case report.
The occurrence of acute leukemia in patients with sickle cell anemia is uncommon. The Philadelphia chromosome is the hallmark of chronic myeloid leukemia. However, it may also be associated with acute lymphoblastic leukemia and acute myeloblastic leukemia. The common BCR-ABL1 transcripts seen in acute lymphoblastic leukemia are e1a2, e13a2, and e14a2, while other transcripts such as e1a3, e13a3, and e6a2 occur rarely. This report describes the presentation, management, and outcome of the occurrence of B-cell acute lymphoblastic leukemia with the rare e1a3 BCR-ABL1 transcript in a patient with sickle cell anemia. A 19-year-old male Nigerian, a known sickle cell anemia patient was admitted on account of severe vaso-occlusive crisis. Examination revealed fever, palor, and jaundice. Full blood count showed anemia and leukocytosis. Peripheral blood and bone marrow smears revealed numerous large and small lymphoblasts in keeping with the L2 subtype of acute lymphoblastic leukemia based on the French-American-British classification. Further evaluation was in keeping with a diagnosis of BCR-ABL1-positive mature B-cell acute lymphoblastic leukemia associated with the rare e1a3 transcript. He was commenced simultaneously on induction chemotherapy and Imatinib while being prepared for allogeneic stem cell transplantation. However, he died  six  months after diagnosis from meningoencephalitis. The occurrence of acute lymphoblastic leukemia with a rare BCR-ABL1 e1a3 transcript in association with sickle cell anemia is uncommon and associated with poor prognosis.
Publication Date: 2021-10-10
Journal: Journal of medical case reports

Aleukemic Extramedullary Blast Crisis as an initial presentation of Chronic Myeloid Leukemia with E1A3 BCR-ABL1 Fusion Transcript.
Right neck swelling and pain occurred in a 49-year-old man. A Blood count showed a slight increase in platelet count without leukemoid reaction. After a biopsy of the cervical mass and bone marrow aspiration, a diagnosis of extramedullary blast crisis (EBC) of chronic myeloid leukemia (CML) was made. FISH analysis showed a BCR-ABL1 fusion signal, but results of RT-PCR for major and minor BCR-ABL1 transcripts were negative. We identified a rare e1a3 BCR-ABL1 fusion transcript. Administration of dasatinib resulted in disappearance of the extramedullary tumor. This is the first reported case of CML-EBC with e1a3 transcript. An aleukemic extramedullary tumor can be the initial presentation of CML.
Publication Date: 2021-09-14
Journal: Internal medicine (Tokyo, Japan)

H396P mutation in chronic myeloid leukaemia patient on nilotinib - A case report.
The advent of BCR-ABL1-targeted therapy with the tyrosine kinase inhibitor (TKI), for example, imatinib and nilotinib, marked a turning point in the therapy of chronic myeloid leukaemia (CML). However, a substantial proportion of patients experience primary or secondary disease resistance to TKI. There are multifactorial causes contributing to the treatment failure of which BCR-ABL1 kinase domain mutation being the most common. Here, we describe a case of a CML patient with H396P mutation following treatment with nilotinib. A 60-year-old woman presented with abdominal discomfort and hyperleukocytosis. She was diagnosed as CML in the chronic phase with positive BCR-ABL1 transcripts. Due to the failure to obtain an optimal response with imatinib treatment, it was switched to nilotinib. She responded well to nilotinib initially and achieved complete haematological and cytogenetic responses, with undetectable BCR-ABL1 transcripts. However, in 4 years she developed molecular relapse. Mutation analysis which was done 70 months after commencement of nilotinib showed the presence of BCRABL1 kinase domain mutation with nucleotide substitution at position 1187 from Histidine(H) to Proline(P) (H396P). Currently, she is on nilotinib 400mg twice daily. Her latest molecular analysis showed the presence of residual BCR-ABL1 transcripts at 0.22%. This case illustrates the importance of BCR-ABL1 mutation analysis in CML patients with persistent BCR-ABL1 positivity in spite of treatment. Early detection and identification of the type of BCRABL1 mutation are important to guide appropriate treatment options as different mutation will have different sensitivity to TKI.
Publication Date: 2021-04-28
Journal: The Malaysian journal of pathology

Clinical Utility of Droplet Digital PCR to Monitor BCR-ABL1 Transcripts of Patients With Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia Post-chimeric Antigen Receptor19/22 T-Cell Cocktail Therapy.
Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph
Publication Date: 2021-04-27
Journal: Frontiers in oncology

Assessment of individual molecular response in chronic myeloid leukemia patients with atypical BCR-ABL1 fusion transcripts: recommendations by the EUTOS cooperative network.
Approximately 1-2% of chronic myeloid leukemia (CML) patients harbor atypical BCR-ABL1 transcripts that cannot be monitored by real-time quantitative PCR (RT-qPCR) using standard methodologies. Within the European Treatment and Outcome Study (EUTOS) for CML we established and validated robust RT-qPCR methods for these patients. BCR-ABL1 transcripts were amplified and sequenced to characterize the underlying fusion. Residual disease monitoring was carried out by RT-qPCR with specific primers and probes using serial dilutions of appropriate BCR-ABL1 and GUSB plasmid DNA calibrators. Results were expressed as log reduction of the BCR-ABL1/GUSB ratio relative to the patient-specific baseline value and evaluated as an individual molecular response (IMR). In total, 330 blood samples (2-34 per patient, median 8) from 33 CML patients (19 male, median age 62 years) were analyzed. Patients expressed seven different atypical BCR-ABL1 transcripts (e1a2, n = 6; e6a2, n = 1; e8a2, n = 2; e13a3, n = 4; e14a3, n = 6; e13a3/e14a3, n = 2; e19a2, n = 12). Most patients (61%) responded well to TKI therapy and achieved an IMR of at least one log reduction 3 months after diagnosis. Four patients relapsed with a significant increase of BCR-ABL1/GUSB ratios. Characterization of atypical BCR-ABL1 transcripts is essential for adequate patient monitoring and to avoid false-negative results. The results cannot be expressed on the International Scale (IS) and thus the common molecular milestones and guidelines for treatment are difficult to apply. We, therefore, suggest reporting IMR levels in these cases as a time-dependent log reduction of BCR-ABL1 transcript levels compared to baseline prior to therapy.
Publication Date: 2021-03-08
Journal: Journal of cancer research and clinical oncology

Glutathione S-transferase gene polymorphic sequence variations: Association with risk and response to Imatinib among Chronic Myeloid Leukemia patients of Kashmir.
Glutathione S-transferase (GST) gene deletion or polymorphic sequence variations lead to decreased enzyme activity that influences susceptibility and response to tyrosine kinase inhibitors in chronic myeloid leukemia (CML). We aimed to analyze relation of different GST gene sequence variants with susceptibility and response to Imatinib in CML. A total of 150 CML cases and equal number of age and gender matched healthy controls were genotyped for five GST polymorphisms by multiplex-PCR and PCR-RFLP techniques. BCR-ABL1 transcripts were quantified by quantitative Real Time PCR (qRT-PCR). GSTT1, GSTO1, and GSTO2 SNPs revealed no association, while as GSTM1 GSTM1
Publication Date: 2021-01-21
Journal: International journal of laboratory hematology

Clinical implications of conventional cytogenetics, fluorescence in situ hybridization (FISH) and molecular testing in chronic myeloid leukaemia patients in the tyrosine kinase inhibitor era - A review.
Chronic myeloid leukaemia (CML) provides an illustrative disease model for both molecular pathogenesis of cancer and rational drug therapy. Imatinib mesylate (IM), a BCR-ABL1 targeted tyrosine kinase inhibitor (TKI) drug, is the first line gold standard drug for CML treatment. Conventional cytogenetic analysis (CCA) can identify the standard and variant Philadelphia (Ph) chromosome, and any additional complex chromosome abnormalities at diagnosis as well as during treatment course. Fluorescence in situ hybridization (FISH) is especially important for cells of CML patients with inadequate or inferior quality metaphases or those with variant Ph translocations. CCA in conjunction with FISH can serve as powerful tools in all phases of CML including the diagnosis, prognosis, risk stratification and monitoring of cytogenetic responses to treatment. Molecular techniques such as reverse transcriptase-polymerase chain reaction (RT-PCR) is used for the detection of BCR-ABL1 transcripts at diagnosis whereas quantitative reverse transcriptase-polymerase chain reaction (qRTPCR) is used at the time of diagnosis as well as during TKI therapy for the quantitation of BCR-ABL1 transcripts to evaluate the molecular response and minimal residual disease (MRD). Despite the excellent treatment results obtained after the introduction of TKI drugs, especially Imatinib mesylate (IM), resistance to TKIs develops in approximately 35% - 40% of CML patients on TKI therapy. Since point mutations in BCR-ABL1 are a common cause of IM resistance, mutation analysis is important in IM resistant patients. Mutations are reliably detected by nested PCR amplification of the translocated ABL1 kinase domain followed by direct sequencing of the entire amplified kinase domain. The objective of this review is to highlight the importance of regular and timely CCA, FISH analysis and molecular testing in the diagnosis, prognosis, assessment of therapeutic efficacy, evaluation of MRD and in the detection of BCR-ABL1 kinase mutations which cause therapeutic resistance in adult CML patients.
Publication Date: 2020-12-29
Journal: The Malaysian journal of pathology

Discontinuation of Maintenance Tyrosine Kinase Inhibitors in Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia outside of Transplant.
The addition of tyrosine kinase inhibitors (TKIs) to chemotherapy has dramatically improved outcomes of patients with Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL). When allogeneic hematopoietic stem cell transplant (HSCT) is performed, maintenance TKI is generally given for a fixed duration. However, the optimal duration of TKI outside of HSCT remains unknown, and the common practice is to continue indefinitely. Here, we report characteristics and outcomes of 9 patients treated with chemotherapy + TKI without HSCT and later discontinued TKI. Among 188 patients with Ph-positive ALL who did not undergo HSCT, 9 of them discontinued maintenance TKI mainly due to side effects. Patients were closely monitored with serial PCR testing for the BCR-ABL1 transcript. Major molecular response (MMR) was defined as BCR-ABL1 transcript ≤0.1% on the international scale for p210 transcripts and a 3-log reduction from baseline for p190 transcripts. Deep molecular remission (DMR) was defined as the absence of quantifiable BCR-ABL1 transcripts with a sensitivity of 0.01%. Molecular relapse was defined as loss of MMR. Treatment-free remission (TFR) was defined from time of TKI discontinuation to molecular relapse, last follow-up, or death from any cause. At the time of TKI discontinuation, transcript level was undetected in 6 patients, <0.01% in 2 patients, and 0.01% in another patient. Prior to discontinuation, the median duration of TKI therapy and of DMR was 70 and 47 months, respectively. No morphological relapse occurred. Three patients (33%) had molecular relapse at a median of 6 months. All 3 resumed TKI therapy, and 2 of them regained DMR after a median of 13 months. After a median follow-up of 49 months, the median TFR was not reached, and the 4-year TFR rate was 65%. The median duration of DMR in patients with and without molecular relapse was 22 and 58 months, respectively (p = 0.096). TKI discontinuation outside of HSCT in Ph-positive ALL in the setting of compelling toxicity may be safe only among a highly selected group of patients with deep and prolonged DMR undergoing close and frequent monitoring. Validation of these findings in prospective clinical trials is highly needed.
Publication Date: 2020-11-26
Journal: Acta haematologica

Treatment-Free Remission in Chronic Myeloid Leukemia Harboring Atypical BCR-ABL1 Transcripts.
Publication Date: 2020-09-22
Journal: Mediterranean journal of hematology and infectious diseases

Practical Laboratory Tools for Monitoring of BCR-ABL1 Transcripts and Tyrosine Kinase (TK) Domain Mutations in Chronic Myeloid Leukemia Patients Undergoing TK Inhibitor Therapy: A Single-Center Experience in Thailand.
The genetic hallmark of CML is known as the appearance of t(9;22)(q34.1;q11.2) (BCR-ABL1) which is present in more than 95% of cases. Here, we demonstrated practical laboratory tools for monitoring of BCR-ABL1 transcripts in chronic myeloid leukemia patients undergoing TK inhibitor therapy. Real time quantitative PCR and direct sequencing were performed for monitoring of BCR-ABL1 transcripts in 245 treated CML. At month 3 after first time point of monitoring, we found that 89% (218/245), 2% (5/245), and 9% (22/245) of patients are determined as optimal, warning, and failure response, respectively. The responses to TKI were slightly decreased at months 6 as following 73% optimal (180/245), 18% warning (43/245), and 9% failure response (22/245). Additionally, responses to TKI were gradually decreased at month 12 after first time point of monitoring as following 65% optimal (160/245), 13% warning (31/245), and 22% failure (54/245). We could detect 20% (49/245) of patients positive for BCR-ABL1 TKD mutations. Interestingly, one third (17 of 49) of TKD mutated cases were positive for compound/polyclonal mutation patterns. While major molecular response were observed in the majority of patients without TKD mutation, resistant to TKI were detected in patients with T315I mutation (n = 9; % mean IS = 8.1510, % median IS = 9.7000), compound/polyclonal mutations with T315I (n = 9; % mean IS = 13.0779, % median IS = 5.404), and other TKD mutations (n = 14; % mean IS = 8.1416, % median IS = 1.060), respectively. Conlusion: These practical laboratory techniques provided a more comprehensive understanding of CML progression during drug therapy and could be of benefit in earlier prognosis.
Publication Date: 2020-07-28
Journal: Asian Pacific journal of cancer prevention : APJCP

Early Prediction of Subsequent Molecular Response to Nilotinib in Patients with Chronic Myeloid Leukemia: Comparison of the Quantification of BCR-ABL1 Ratios Using ABL1 or GUSB Control Genes.
Molecular monitoring of BCR-ABL1 transcripts is a critical prognostic indicator of treatment response in chronic myeloid leukemia (CML). Quantification of BCR-ABL1 transcripts using ABL1 or GUSB as control genes on the early molecular response (MR) to frontline nilotinib was studied using data from 60 patients with chronic-phase CML from the Evaluating Nilotinib Efficacy and Safety in Clinical Trials as First-Line Treatment (ENEST1st) substudy. Effects of BCR-ABL1/ABL1 and BCR-ABL1/GUSB ratios at early time points as independent variables on subsequent MR were determined by logistic regression analyses and predictive cut-off values determined by receiver operating curve analyses. From day 45, concordance was found for both control genes' early transcript kinetics and ability to predict subsequent deep MR at 18 months. From baseline to 3 months, transcripts descended linearly with both control genes. Use of ABL1 allowed for an earlier prediction (2 months) of subsequent MR than with GUSB (3 months), with cut-off values of 1.5% and 0.19%, respectively. The dynamic determination of BCR-ABL1 transcripts using either internal control gene is valid and predictive of subsequent MR. The use of GUSB to predict an earlier and more accurate response than ABL1 is not supported in the results. Accurate early indicators of MR are essential to identify patients likely to have inferior outcomes who may benefit from treatment with an alternative tyrosine kinase inhibitor.
Publication Date: 2020-07-21
Journal: The Journal of molecular diagnostics : JMD

Genotype-phenotype correlation of unusual BCR-ABL1 transcripts in Philadelphia chromosome-positive leukaemia.
Publication Date: 2020-04-03
Journal: British journal of haematology

Frequency and spectrum of atypical BCR-ABL1 transcripts in chronic myeloid leukemia.
Publication Date: 2020-04-02
Journal: Experimental oncology

Long-term results of a phase 2 trial of nilotinib 400 mg twice daily in newly diagnosed patients with chronic-phase chronic myeloid leukemia.
Nilotinib is a potent, second-generation inhibitor of BCR-ABL1 tyrosine kinase and has been approved as frontline and salvage therapy for patients with chronic-phase chronic myeloid leukemia (CP-CML). In this single-institution, phase 2 study, 122 patients with newly diagnosed CP-CML received nilotinib 400 mg twice daily. The median follow-up on study was 78.3 months (interquartile range, 58.4-96.5 months). Fifty-six percent of patients remained on therapy at the last follow-up. Both the complete cytogenetic response rate and the major molecular response (MR) rate were 91%. Seventy-five percent and 59% of patients achieved a ≥4.5-log reduction in BCR-ABL1 transcripts (MR4.5) and a sustained MR4.5 beyond 2 years, respectively. The estimated event-free survival and overall survival rates at 5 years were 89% and 93%, respectively, and the corresponding rates at 10 years were 85% and 88%, respectively. Treatment discontinuation due to toxicity occurred in 19% of patients, mostly because of cardiovascular events (10%) and biochemical abnormalities (6%). The top 3 nonhematologic toxicities were rash (55%), elevated bilirubin (57%), and elevated aminotransferases (48%). Hematologic toxicity was transient and mild. Ischemic cardiovascular adverse events occurred in 8% of patients. Four patients (3%) progressed to accelerated or blast phase while on therapy, and 7 patients (6%) died on study. The current data confirm the long-term efficacy of nilotinib 400 mg twice daily in patients with CP-CML. A majority of patients can achieve sustained MR4.5.
Publication Date: 2020-01-31
Journal: Cancer

Long-term results of frontline dasatinib in chronic myeloid leukemia.
Dasatinib is a second-generation tyrosine kinase inhibitor that, when used as frontline therapy, produces more and faster cytogenetic and molecular responses compared with imatinib. The authors report the long-term follow-up from the first study using dasatinib as initial therapy for chronic-phase chronic myeloid leukemia. Between November 2005 and August 2014, patients were randomly assigned to receive 100 mg daily or 50 mg twice daily. After June 2009, all patients started with 100 mg daily. With a median follow-up of 6.5 years, 94 of 149 treated patients (63%) were still receiving dasatinib on study. The median patient age was 48 years (interquartile range, 37-55 years), and 9% of patients had a high risk Sokal risk score. The cumulative complete cytogenetic response rate at 11 years was 92.6%, the major molecular response (MR) rate was 88.2%, and the MR4.5 rate (indicating a ≥4.5-log reduction in BCR-ABL1 transcripts) was 79.5%. The median time to a major MR and MR4.5 was 6 and 23 months, respectively. A sustained MR4.5 (≥2 years) was achieved in 82 patients (55%). The 10-year overall survival, transformation-free survival, event-free survival, and failure-free survival rates were 89%, 95%, 86%, and 65%, respectively. Univariate analysis showed that the achievement of a complete MR was associated with improved overall survival. The most common reasons for treatment discontinuation were toxicity and elective discontinuation. The most common treatment-emergent grade 3 and 4 adverse events were fatigue, thrombocytopenia, and infections. After this long-term follow-up, dasatinib continues to show an excellent safety profile and produces rapid cytogenetic responses and MRs, durable deep MRs, and excellent long-term survival outcomes in patients with chronic-phase chronic myeloid leukemia.
Publication Date: 2020-01-31
Journal: Cancer

Assessing Measurable Residual Disease in Chronic Myeloid Leukemia. BCR-ABL1 IS in the
Chronic myelogenous leukemia (CML) is a malignancy of the myeloid cell lineage characterized by a recurrent chromosomal abnormality: the Philadelphia chromosome, which results from the reciprocal translocation of the chromosomes 9 and 22. The Philadelphia chromosome contains a fusion gene called BCR-ABL1. The BCR-ABL1 codes for an aberrantly functioning tyrosine kinase that drives the malignant proliferation of the founding clone. The advent of tyrosine kinase inhibitors (TKI) represents a landmark in the treatment of CML, that has led to tremendous improvement in the remission and survival rates. Since the introduction of imatinib, the first TKI, several other TKI have been approved that further broadened the arsenal against CML. Patients treated with TKIs require sensitive monitoring of BCR-ABL1 transcripts with quantitative real-time polymerase chain reaction (qRT-PCT), which has become an essential part of managing patients with CML. In this review, we discuss the importance of the BCR-ABL1 assay, and we highlight the growing importance of BCR-ABL1 dynamics. We also introduce a mathematical correction for the BCR-ABL1 assay that could help homogenizing the use of the ABL1 as a control gene. Finally, we discuss the growing body of evidence concerning treatment-free remission. Along with the continuous improvement in the therapeutic arsenal against CML, the molecular monitoring of CML represents the
Publication Date: 2019-10-15
Journal: Frontiers in oncology

[Recommendations from the French CML Study Group (Fi-LMC) for BCR-ABL1 kinase domain mutation analysis in chronic myeloid leukemia].
In the context of chronic myeloid leukemia (CML) resistant to tyrosine kinase inhibitors (TKIs), BCR-ABL1 tyrosine kinase domain (TKD) mutations still remain the sole biological marker that directly condition therapeutic decision. These recommendations aim at updating the use of BCR-ABL1 mutation testing with respect to new available therapeutic options and at repositioning different testing methods at the era of next generation sequencing (NGS). They have been written by a panel of experts from the French Study Group on CML (Fi-LMC), after a critical review of relevant publications. TKD mutation testing is recommended in case of treatment failure but not in case of optimal response. For patients in warning situation, mutation testing must be discussed depending on the type of TKI used, lasting of the treatment, kinetic evolution of BCR-ABL1 transcripts along time and necessity for switching treatment. The kind and the frequency of TKD mutations occasioning resistance mainly depend on the TKI in use and disease phase. Because of its better sensitivity, NGS methods are recommended for mutation testing rather than Sanger's. Facing a given TKD mutation, therapeutic decision should be taken based on in vitro sensitivity and clinical efficacy data. Identification by sequencing of a TKD mutation known to induce resistance must lead to a therapeutic change. The clinical value of testing methods more sensitive than NGS remains to be assessed.
Publication Date: 2019-07-30
Journal: Bulletin du cancer

Efficacy of Dasatinib in a Very Elderly CML Patient Expressing a Rare E13a3
We report the case of an 89-year-old male diagnosed with chronic-phase CML and expressing a rare e13a3 BCR-ABL1 fusion transcript. His cytogenetic analysis showed the t(9;22) translocation generating the Philadelphia chromosome (Ph), with a multiplex RT-PCR detecting an atypical fragment. Using two primers complementary to exon 10 of BCR and exon 4 of ABL1, a larger PCR product was observed, where after Sanger sequencing, an e13a3 BCR-ABL1 transcript was revealed. Given the diagnosis, the patient received 100 mg of dasatinib every other day and was then monitored by measuring both hematological and cytogenetic parameters, while his BCR-ABL1 transcripts were examined by PCR and semi-nested-PCR. According to the 2013 European Leukemia Network criteria, after six months of dasatinib the patient's response was classified as warning as he displayed 20% of Philadelphia-positive metaphases. Sequencing of the ABL1 catalytic domain did not detect point mutations. A complete cytogenetic response was achieved after one year of dasatinib. However, semi-nested-PCR confirmed the presence of the e13a3 BCR-ABL1 fusion transcript that has persisted up to the latest follow-up visit.
Publication Date: 2019-07-03
Journal: Anticancer research

Clinical characteristics and prognostic significance of chronic myeloid leukemia with rare BCR-ABL1 transcripts.
The prognostic significance of rare BCR-ABL1 transcripts is uncertain in the tyrosine kinase inhibitor (TKI) era. In this retrospective study, 40 (1.7%) patients with rare BCR-ABL1 transcripts were identified from a cohort of 2331 chronic myeloid leukemia (CML) patients; 4 types of rare transcripts were identified, including e1a2 (0.9%), e19a2 (0.4%), e13a3 (0.1%), and e14a3 (0.3%). Compared to patients with the typical transcript, those with the e1a2 transcript had an inferior response to TKIs and a worse outcome. Patients with the e19a2 transcript had a high rate of early optimal response to TKIs, but most of them later lost the complete cytogenetic response (CCyR) due to BCR-ABL1 mutations, resulting in a poor prognosis. Patients with the e13a3/e14a3 transcript responded well to TKIs and had a good outcome. These findings indicate that the type of BCR-ABL1 transcript should be considered when determining the treatment for CML patients in the TKI era.
Publication Date: 2019-07-02
Journal: Leukemia & lymphoma

Low-level BCR-ABL1 transcripts in individuals without overt hematologic malignancy.
Publication Date: 2019-05-03
Journal: Leukemia research

bcr-abl1 kinase domain(4)

bcr-abl1 fusion transcript(4)

bcr-abl1 rna levels(2)

response mmr(4)

response ccyr(3)

disease mrd(3)

halving time(2)

pcr rq-pcr(2)

gene fg(2)