The clinicopathological spectrum and driver mutation profile in classic BCR-ABL1 negative myeloproliferative neoplasms: a three-year study from a tertiary care center in Kerala, South India

Background: Myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell disorders primarily of the adults. The 2016 World Health Organization (WHO) classification of MPNs include the molecular landscape as one of the diagnostic criteria. JAK2 exon14 (JAK2 V617F), JAK2 exon12, Myeloproliferative leukemia virus oncogene exon 10 (MPL 515), and calreticulin exon 9 (CALR) mutations are the main somatic driver mutations detected in classic BCR-ABL1 negative MPNs. Methods: A retrospective, cross-sectional study was conducted including 99 patients diagnosed with classic BCR-ABL1 negative MPNs during a 3-year time period, from March 2018 to February 2021 in the departments of pathology and clinical haematology- haemato oncology of a tertiary care teaching hospital. Clinical, haematological and morphological features were analysed and correlated with MPN associated mutation studies done in blood/bone marrow samples. Results: The prevalence of polycythaemia vera (PV) was found to be higher than other MPN, two third of which were JAK2 positive. More than half of the cases of primary myelofibrosis (PMF) and essential thrombocythemia (ET) also showed JAK2 mutation. CALR was positive in 17.4% of ET and 31.3% of PMF; MPL in 4.4% of ET and 3.1% of PMF. Conclusions: The prevalence of triple-negative MPN point towards the need for whole-exome sequencing of triple-negative MPN.

Analysis of mutation characteristics in TKI-resistant chronic myeloid leukemia patients based on next-generation sequencing technology / 白血病·淋巴瘤

Objective:To explore the characteristics and patterns of gene mutations in tyrosine kinase inhibitor (TKI)-resistant chronic myeloid leukemia (CML) patients and their relationship with TKI-resistant CML.Methods:A retrospective case series study was performed. Clinical data and next-generation sequencing results from TKI-resistant CML patients in Nanfang Hospital of Southern Medical University and Yuebei People's Hospital of Shantou University Medical College from August 2018 to November 2022 were retrospectively analyzed, and the gene mutations of the patients in general and at different disease stages were analyzed.Results:Sixty patients were enrolled, with the age [ M ( Q1, Q3)] of 41.5 years old (32 years old, 53 years old); 38 cases (63.33%) were male and 22 cases (36.67%) were female; 43 cases were in the chronic stage, and 17 cases were in the progression stage (3 cases were in the accelerated stage and 14 cases were in the blast stage). non-ABL1 mutations were detected in 30 patients (50.00%) including 45 times of 15 non-ABL1 genes. The number of non-ABL1 mutation gene was 1 (0, 2) in 60 patients. Of the 60 patients, 21 (35.00%) had ASXL1 mutations, 5 (8.33%) had DNMT3A mutations, 5 (8.33%) had RUNX1 mutations, and 3 (5.00%) had SETBP1 mutations; the proportions of patients with 1 and ≥2 non-ABL1 mutations were 33.33% (20/60) and 16.67% (10/60), respectively. The total detection rates of non-ABL1 mutations were 52.94% (9/17) and 48.84% (21/43), and the detection rates of ≥2 non-ABL1 mutations were 23.53% (4/17) and 13.95% (6/43) in patients with progression and patients with chronic disease, and the differences were not statistically significant ( χ2 = 0.08, P = 0.774; χ2 = 0.80, P = 0.370). Seventeen of 60 patients (28.33%) had mutations in the ABL1 kinase region, of which 14 (82.35%) had non-ABL1 mutations; of these 17 cases, 6 patients with progressive disease all had non-ABL1 mutations, in 11 patients with chronic disease, 8 patients had non-ABL1 mutations, and the difference was not statistically significant ( P = 0.452). Conclusions:Patients with TKI-resistant CML have high frequencies of non-ABL1 mutations, and there is a trend for higher mutation rates in patients with progressive disease than in patients with chronic disease, and these may be related to the abnormal activation of ABL1 kinase by BCR-ABL1 fusion gene in patients with drug-resistant CML, which leads to the genome-level and epigenome-level mutations, and driving disease progression from chronic phase to accelerated or blast phase.

Efficacy and safety of switching to flumatinib in patients with chronic myeloid leukemia who have not achieved optimal response or are intolerant to TKI treatment / 陆军军医大学学报

Objective To observe the efficacy and safety of flumatinib conversion in chronic myelogenous leukemia-chronicphase(CML-CP)patients with suboptimal TKI response or intolerance.Methods Patients who did not have the best response or intolerance to first-line imatinib,dasatinib,and nilotinib and switched to flumatinib(600 mg/d)from February 2020 to August 2022 were collected from 5 hospitals from Chongqing and affiliated hospitals of North Sichuan Medical College.The efficacy and safety of flumatinib were observed.The optimal response rate,major molecular response(MMR),cumulative complete cytogenetic response(CCyR)rate,cumulative MMR rate,cumulative deep molecular response(DMR),progression-free survival(PFS),event-free survival(EFS)and adverse reactions in 3,6 and 12 months after treatment were observed and analyzed.Results A total of 100 patients with CML-CP were enrolled,with a median follow-up of 18(3～36)months.The optimal response rate was 92.6％(88/95),94.4％(85/90)and 92.9％(79/85)respectively,at 3,6 and 12 months after treatment.Till August 20,2023,the cumulative CCyR and MMR rate was 98.0％(98/100)and 81.9％(77/94),respectively,the median time to reach CCyR and MMR was 3 months,and cumulative DMR rate was 51.0％(51/100).PFS rate was 100.0％(100/100)and 1-year EFS rate was 85.6％(75/90).The most common non-hematologic adverse reactions of flumatinib were diarrhea and abdominal pain(7.0％),followed by renal dysfunction(6.0％)and musculoskeletal pain(2.0％).The main hematologic adverse reactions were thrombocytopenia(12.0％),anemia(6.0％)and leukopenia(2.0％).Conclusion Flumatinib has better MMR and DMR and is well tolerated in CML-CP patients with TKI resistance or intolerance.

Design, synthesis and structure-activity relationship of a series of novel BCR-ABL inhibitors / 中国药科大学学报

@#Abstract: In this study, molecular skeleton I N-phenylindoline-5-formamide was obtained by optimizing the structure of the existing allosteric BCR-ABL inhibitor asciminib. Based on this molecular skeleton, compounds 1-12 were designed and synthesized assisted by molecular docking. After characterizing their structures using ESI-MS and NMR, the anti-BCR-ABL1-dependent Luc-Ba/F3 cell proliferation activity of the target compounds in vitro was determined by CCK-8 assay. Finally, highly active lead compound 1 was screened out. For high clearance rate and short half-life period exposed in subsequent druggability evaluation, its druggability was optimized by introducing hydrophilic groups. Afterwards, compounds 13-22 were designed and synthesized. Compound 17 presented high cell inhibitory activity, low clearance rate and long half-life, and is expected to be used as a clinical candidate for further evaluation of biological activity and druggability.

Response to Tyrosine Kinase Inhibitors in Patients with BCR-ABL1 Positive Chronic Myeloid Leukemia; 13.5 Years’ Experience at Patan Hospital, Nepal

Background:Since the advent of Tyrosine Kinase Inhibitor (TKI), well controlled studies in developed world have shown that the life expectancy of patients with CML is comparable to normal people without the disease. But long-term follow up studies are lacking in resource poor setting. Methods:This is a retrospective follow up study looking at the molecular response and resistance to Tyrosine Kinase Inhibitors (TKI) in patients enrolled in the Max Access Program since February 2003 till March 2017. Patients with twoor more BCR-ABL1 levels by Karyotyping/ fluorescent in situ hybridization (FISH) / reverse transcriptase polymerase chain reaction (RT-PCR) were included. At baseline, complete blood count (CBC), renal function test (RFT), and liver function test (LFT) were evaluated. Bone marrow aspiration and biopsy for morphology, cytogenetic analysis by Karyotyping/FISH and/or molecular analysis by RT-PCR were also done if these tests were not performed earlier. FISH or RT-PCR was done on peripheral blood every 3–12 months as necessary if the patient could afford. Patients with warning response/failure underwent BCR-ABL1 Resistance Mutation Analysis (IRMA).Results:Three hundred and forty six (346) patients had two or more BCR-ABL1 monitoring tests done. Optimal response was seen in 49.42%. Similarly, suboptimal response and failure were seen in 16.5% and 34% respectively. Overall Survival is 89.6% (at 1.8 -165 months, mean 62 months) . If only CML related events is considered survival is 95.9%. Seventy seven (77) patients with a total of 80 BCR-ABL1 domain Imatinib Resistance Mutation Analyses (IRMA) showed 19 different types of mutations with the most common being T315I mutation (8 and 19.5%). About 22.25% of the total patients showed resistance to Glivec out of which 10.98% showed mutations. Nine patients underwent trial for treatment free response (TFR) and 5 of them relapsed between 2-8 months.Conclusions:Despite all the odds of having financial problem, accessibility problem due to distances, transportation, etc. and difficulty monitoring with routine BCR-ABL1 and IRMA, our findings show that the outcome of TKI therapy in our CML patients is comparable to well controlled studies done elsewhere. Overall survival, molecular and cytogenetic responses and mutations in our patients who developed resistance as well as TFR are also similar to other studies. The resistance rate of 22.25% is slightly higher compared to other studies in developed world. This is mainly because of poor monitoring due to unavailability of the test including IRMA in our country and affordability until 2012. It proves that TKI is very effective in CML even in a resource-poor, developing country

Microarray analysis reveals distinct immune signatures in BCR?ABL positive and negative myeloproliferative neoplasms

Background: BCR?ABL mutation on the Philadelphia chromosome is the key driver of chronic myeloid leukemia (CML) pathogenesis. However, there are certain cases of myeloproliferative neoplasms (MPN) wherein no inherent driver mutation is detected resulting in clinical phenotype. It is important to identify key genes and pathways in driving the disease. The aim of the study was to use a gene-based omics approach to molecularly characterize these mutation-positive and negative cases to further strengthen diagnostics and precision medicine. Methods: A microarray profiling was done on CD34 positive cells isolated from two BCR?ABL positive and five BCR?ABL negative samples. JAK2V617F mutation testing was also done to rule out the presence of any other mutation in the latter group. The fold change cut-off was taken as �5 with p?0.5 for significant genes. The gene network and pathway analysis were done using DAVID and STRING software. Results: The genes upregulated in BCR?ABL negative samples were shown to be involved in immune regulation, signal transduction and T- and B-cell signalling. The protein-protein interaction network of upregulated genes in these samples were enriched for various immunomodulatory genes such as HLADP, HLADQ , IL7R, CCR7, CD3 subtypes. These genes further formed a network with signal transduction genes such as LCK, FYN, RAG1, DOCK1, AKT3, SMAD3, LEF1. Conclusion: The results suggested a modulation of immune response genes and its subsequent effect on oncogenic signalling in BCR?ABL negative samples as compared to BCR?ABL positive samples. The protein network analysis was enriched for genes involved in Src, TGF-beta and PI3K-AKT pathway contributing to the proliferation of neoplastic clone.

Advances in the study of new BCR-ABL kinase inhibitors / 药学学报

The oncogenic product of BCR-ABL is an abnormal tyrosine kinase that causes chronic myeloid leukemia (CML). With further research into the pathogenesis of CML, the discovery of compounds that selectively inhibit abnormal BCR-ABL tyrosine kinases is a research focus worthy of attention. The first three generations of BCR-ABL inhibitors are orthosteric inhibitors, which competitively block the binding of ABL protein tyrosine kinase to ATP and prevent it from activating downstream signals. The fourth-generation BCR-ABL inhibitors allosterically inhibit ABL protein tyrosine kinase by binding to the myristoyl pocket, providing greater selectivity and maintaining activity against drug-resistant mutations proteins. Novel drug design strategies such as proteolytic targeting chimera (PROTAC), covalent inhibitors and dual targeting inhibitors also provide new directions for the development of BCR-ABL kinase inhibitors. This paper reviews recent research advances on BCR-ABL kinase inhibitors and discusses drug design strategies for various novel BCR-ABL inhibitors.

Progress of Wnt signaling pathway in peripheral T-cell lymphomas / 白血病·淋巴瘤

As a rare and heterogeneous group of non-Hodgkin lymphomas, most of peripheral T-cell lymphomas (PTCL) are highly aggressive and usually do not respond well to chemotherapy. The research found that the disorder of canonical Wnt signaling pathway is involved in the pathogenesis of some subtypes of PTCL. Canonical Wnt signaling pathway plays an important role in the development and differentiation of T-lymphocytes and tumorigenesis. In recent years, exploring the relationship between canonical Wnt signaling pathway and the development of PTCL is expected to provide new ideas and targets for the treatment of PTCL.

Study on the mechanism of luteolin reversing multidrug resistance in leukemia K562/ADR cells / 天津医药

Objective To investigate the mechanism of luteolin's(Lut)reversal effect on multidrug resistance of chronic myeloid leukemia K562/ADR cells.Methods CCK-8 assay was used to detect drug resistance in K562 and K562/ADR cells 24 hours after treatment with different doses of adriamycin(ADR).CCK-8 assay was used to assess the cytotoxicity and sensitizing effect of Lut on ADR after K562/ADR cells were treated with Lut alone or in combination with ADR for 24 hours.K562/ADR cells in logarithmic growth phase were separated into three group:0μmol/L Lut,2μmol/L and 4μmol/L Lut groups.ADR accumulation in cells was measured using flow cytometry.Nuclear factor erythroid-2-related factor 2(Nrf2),multidrug resistance associated protein 1(MRP1),P-glycoprotein(P-gp)and glutathione-S-transferase-PI(GST-pi)mRNA and protein expressions were identified using RT-PCR and Western blot assay.Glutathione(GSH)kit was used to detect intracellular GSH content.Results Compared with K562 cells,K562/ADR cell line was significantly resistant to ADR,and the drug resistance was 53.69 times.K562/ADR cell proliferation was decreased to variable degrees by different doses of Lut when compared to the 0μmol/L Lut group(P＜0.05).The proliferation inhibition rates of K562/ADR cells treated with 2 and 4μmol/L Lut were less than 10%,indicating that the concentration of Lut was non-toxic.Compared with the 0 μmol/L Lut group,the 2 μmol/L Lut group and the 4 μmol/L Lut group showed significantly increased ADR growth inhibition rate on K562/ADR and increased accumulation of ADR in cells,improved the reversal resistance fold,and decreased GSH content in cells.MRP1,P-gp,GST-pi and Nrf2 mRNA and protein expression were reduced in cells(P＜0.05).The effect of 4 mol/L Lut was greater than that of 2 mol/L Lut.Conclusion Lut may decrease K562/ADR cell proliferation and reverse ADR medication resistance.The mechanism could be connected to the downregulation of Nrf2,MRP1,P-gp and GST-pi expression,which leads to an increase in ADR accumulation in K562/ADR cells.

Analytic performance validation of laboratory-developed real-time quantitative PCR (RQ-PCR) test for BCR::ABL1 p210 transcript in chronic myeloid leukemia / 中华检验医学杂志

Objective:To establish and validate analytic performance of laboratory-developed real-time quantitative polymerase chain reaction (RQ-PCR) test (LDT) for BCR::ABL1 p210 transcript.Methods:Using the primes and probes released by the Europe Against Cancer Program(EAC), we have established BCR::ABL1 p210 RQ-PCR test. The laboratory-specific conversion factor (CF) was determined by the WHO 1 st International Genetic Reference Panel, and a two-level internal control is developed using a mixture of K562 and HL60 cell lines was created to ensure traceability. Analytical performance, including analytical accuracy, analytical precision, linearity range, analytic sensitivity and specificity of RQ-PCR LDT test for BCR::ABL1 p210 transcript were validated according to CLIS guidelines. Furthermore, a comparison was made with an FDA-cleared RQ-PCR in vitro diagnostics (IVD) kit by Bland-Altman analysis. Results:The laboratory specific conversion factor (CF) for LDT RQ-PCR was determined to be 0.535 based on WHO 1 st International Genetic Reference Panel, which can be used to convert to the BCR::ABL international scale (BCR::ABL1 IS) reliably. The repeatability of BCR::ABL1 IS results at 4 different molecular response (MR0.5,MR1.5,MR2.5,MR3.5) levels are 7.44%, 5.33%, 9.12% and 18.06%, respectively, with total precision of 7.99%, 5.49%, 10.95% and 17.99%. The previous CAP proficiency test (PT) results from our laboratory were within the acceptable range of variation. MR results of our laboratory and MR mean value of all CAP-PT laboratory is highly correlated ( r=0.999, P<0.01), and consistent according to Bland-Altman analysis. Furthermore, the LDT method in our laboratory has a high correlation with the test results of FDA-cleared Qiagen IVD kit ( r=0.997, P<0.01). BCR::ABL1 IS results of BCR::ABL1 e13a2 transcript showed linearity within the range of 0.001%-7.454%, with a maximum coefficient of variation (% CV) 64.09%. The linearity range of e14a2 transcript BCR::ABL1 IS was 0.002%-12.398%, with a maximum % CV of 43.37%. The test has a limit of detection (LoD) of MR5.0 (0.001% IS) for e13a2 and MR4.8 (0.002% IS) for e14a2 transcript, respectively. The limit of quantitation (LoQ) for both e13a2 and e14a2 transcripts was MR4.7 (0.002% IS). The test exhibited 100% specificity, with no cross-reactivity observed between the p190 transcript and p210. Conclusions:The analytic performance of BCR::ABL1 p210 LDT RQ-PCR test from our laboratory is excellent, which can meet the clinical needs of BCR::ABL1 detection in patients with chronic myeloid leukemia.

Comparison of BCR::ABL (P210) mRNA levels detected by dPCR and qPCR methods in patients with chronic myeloid leukemia / 中华血液学杂志

Objective: To compare digital polymerase chain reaction (dPCR) and real-time quantitative PCR (qPCR) measurements of BCR::ABL (P210) mRNA expression in patients with chronic myeloid leukemia (CML) . Methods: In this non-interventional, cross-sectional study, BCR::ABL (P210) mRNA was simultaneously measured by dPCR and qPCR in peripheral blood samples collected from patients with CML who underwent tyrosine kinase inhibitor therapy and who achieved at least a complete cytogenetic response from September 2021 to February 2023 at Peking University People's Hospital. The difference, correlation, and agreement between the two methods were evaluated using the Wilcoxon signed-rank test, Spearman's correlation, and Bland-Altman analysis, respectively. Results: In total, 459 data pairs for BCR::ABL mRNA expression measured by dPCR and qPCR from 356 patients with CML were analyzed. There was a significant difference in BCR::ABL mRNA expression between the two methods (P<0.001). When analyzed by the depth of the molecular response (MR), a significant difference only existed for patients with ≥MR4.5 (P<0.001). No significant difference was observed for those who did not achieve a major MR (no MMR; P=0.922) or for those who achieved a major MR (MMR; P=0.723) or MR4 (P=0.099). There was a moderate correlation between the BCR::ABL mRNA expression between the two methods (r=0.761, P<0.001). However, the correlation gradually weakened or disappeared as the depth of the MR increased (no MMR: r=0.929, P<0.001; MMR: r=0.815, P<0.001; MR4: r=0.408, P<0.001; MR4.5: r=0.176, P=0.176). In addition, the agreement in BCR::ABL mRNA expression between the two methods in those with MR4.5 was weaker than other groups (no MMR: ▉= 0.042, P=0.846; MMR:▉=0.054, P=0.229; MR4:▉=-0.020, P=0.399; MR4.5:▉=-0.219, P<0.001) . Conclusions: dPCR is more accurate than qPCR for measuring BCR::ABL (P210) mRNA expression in patients with CML who achieve a stable deep MR.

Efficacy and safety of flumatinib in treatment of imatinib-resistant or imatinib-intolerant patients with chronic myeloid leukemia / 白血病·淋巴瘤

Objective:To investigate the efficacy and safety of flumatinib in the treatment of imatinib-resistant or imatinib-intolerant patients with chronic phase chronic myelogenous leukemia (CML-CP).Methods:The clinical data of 9 CML-CP patients who received flumatinib after imatinib resistance or intolerance in Jining No. 1 People's Hospital from April 2020 to May 2021 were retrospectively analyzed. Patients were evaluated for the hematologic, cytogenetic and molecular responses, progression-free survival (PFS), event-free survival (EFS), and adverse reactions.Results:Among 9 CML-CP patients, there were 4 imatinib-resistant patients and 5 imatinib-intolerant patients. The median duration of flumatinib exposure was 17 months (1-25 months). Except for 1 case who discontinued flumatinib early due to grade 4 thrombocytopenia and other adverse reactions, 7 of the remaining 8 cases achieved the best response at 3, 6 and 12 months of flumatinib therapy. By the end of follow-up in April 2022, 7, 7 and 6 patients achieved complete cytogenetic response (CCyR), major molecular response (MMR) and molecular response 4.5 (MR4.5), respectively. The median time to achieving CCyR, MMR and MR4.5 was 4.5 months (3-6 months), 12 months (3-12 months) and 15 months (3-21 months), respectively. Within 17 months (11-25 months) of follow-up, 7 of the 9 patients had EFS and 8 patients with continuous flumatinib had PFS. Among 9 patients treated with flumatinib, hematologic adverse reactions were observed in 6 cases, and grade 3-4 hematologic adverse reactions occurred in 2 cases. Non-hematologic reactions events mainly included diarrhea (4 cases), muscle ache (2 cases), fatigue (2 cases) and liver damage (2 cases), which were all grade 1-2.Conclusions:Flumatinib is effective and well tolerated in the treatment of imatinib-resistant or imatinib-intolerant CML-CP patients.

Pediatric chronic myeloid leukemia in myeloid blast crisis

ABSTRACT Chronic myeloid leukemia (CML) accounts for 2-3% of childhood leukemias. About 5% of cases present in a blastic phase of CML which clinically and morphologically mimics more common acute leukemias of childhood. We report a case of a 3-year-old male who presented with gradual onset swelling of the abdomen and extremities along with generalized weakness. Examination revealed massive splenomegaly, pallor, and pedal edema. Initial workup showed anemia, thrombocytopenia, and leukocytosis (120,000/uL) with a blast percentage of 35%. Blasts were positive for CD13, CD33, CD117, CD34 and HLA-DR, and stained negative for Myeloperoxidase and Periodic Acid Schiff. Fluorescence in situ hybridization was positive for b3a2/e14a2 junction BCR-ABL1 transcript and negative for RUNX1-RUNX1T1/t(8;21), clinching the diagnosis of CML in myeloid blast crisis. The patient expired within 17 days of diagnosis and initiation of therapy.

Role of ancillary techniques in diagnosis, therapy and prognosis of a case of precursor B-cell acute lymphoblastic leukemia in an elderly patient

The chromosomal abnormality of Philadelphia chromosome is mostly seen in Chronic Myeloid Leukemia (CML). But it is observed that the Philadelphia chromosome (Ph), t(9,22), is the most common cytogenetic abnormality in adult patients with acute lymphoblastic leukemia (ALL), occurring in about 20% to 30 % of all cases. Patients with Ph-positive ALL have breaks in the minor breakpoint region, m?BCR (exons 1?2) lead to a short fusion proteins (p190) and is most frequently associated with Ph chromosome- positive ALL. They have an increased risk for central nervous system (CNS) involvement, an aggressive clinical course and poor prognosis. Historically, they had an inferior outcome when compared with their Ph-negative counterparts. Adult Ph+ patients achieve Complete Remission rates comparable to Ph? ALL patients with standard chemotherapy, but the remissions are short and survival poor. The addition of tyrosine kinase inhibitors (TKIs) including imatinib has dramatically improved outcomes. We are presenting this case report of t(9;22), p190 BCR-ABL1 positive ALL in an elderly female patient of south Gujarat.

¿Es importante conocer el tipo de transcripto BCR-ABL en la leucemia mieloide crónica? / Is it important to know the type of BCR-ABL transcript in chronic myeloid leukemia?

La leucemia mieloide crónica se caracteriza por la ocurrencia de una translocación recíproca entre los cromosomas 9 y 22; que da origen a un cromosoma 22 derivativo conocido como Filadelfia. En el sitio de unión se forma el gen de fusión BCR-ABL que conlleva a la síntesis de una proteína híbridacon propiedades oncogénicas. El sitio de unión entre los cromosomas 9 y 22 es variable y da lugar a transcritos diferentes; los conocidos como e13a2 y e14a2 son los más frecuentes y estudiados. El análisis de las características clínico-hematológicas de presentación y la respuesta al tratamiento entre los pacientes portadores de e13a2 o e14a2 ha revelado diferencias que pueden ser útiles para la predicción del pronóstico. Se realizó una revisión de la literatura científica a través de PUBMED. Se analizó y resumió la información. Se evidencian diferentes características de presentación, pero no existe coincidencia entre todos los autores. Respecto al comportamiento de la respuesta al tratamiento con inhibidores de tirosina quinasa, algunos autores encuentran diferencias y algunos sugieren que puede tratarse de dos enfermedades diferentes. Puede ser importante conocer el tipo de transcripto BCR-ABL en la LMC ya que, al menos entre los dos más frecuentes, existen diferencias que pueden ser útiles en la predicción del pronóstico para el paciente, así como para el manejo del tratamiento(AU)

Chronic myeloid leukemia is characterized by the occurrence of a reciprocal translocation between chromosomes 9 and 22; which gives rise to a derivative chromosome 22 known as Philadelphia. At the binding site, the BCR-ABL fusion gene is formed, which leads to the synthesis of a hybrid protein with oncogenic properties. The binding site between chromosomes 9 and 22 is variable and gives rise to different transcripts; those known as e13a2 and e14a2 are the most frequent and studied. The analysis of the clinical-hematological characteristics of presentation and the response to treatment among patients with e13a2 or e14a2 has revealed differences that may be useful for the prediction of prognosis. To describe the different characteristics reported for one or another transcript and to know if it is important to know the type of transcript in the CML. A review of the scientific literature was carried out through PUBMED. The information was analyzed and summarized. Different presentation characteristics are evident but there is no coincidence between all the authors. Regarding the behavior of the response to treatment with tyrosine kinase inhibitors, some authors find differences and some suggest that it may be two different entities. It may be important to know the type of BCR-ABL transcript in CML cause, at least between the two most frequent, there are differences that may be useful in predicting the prognosis for the patient as well as for the management of treatment(AU)

Brazilian chronic myeloid leukemia working group recommendations for discontinuation of tyrosine kinase inhibitors in chronic myeloid leukemia in clinical practice

ABSTRACT Introduction: Treatment-free remission (TFR) is a new goal of chronic myeloid leukemia (CML) therapy. TFR is feasible when the patient has achieved a deep and stable molecular response and met the criteria required to ensure its success. Treatment discontinuation should not be proposed to the CML patient if minimum conditions are not met. In Brazil, for example, molecular tests (BCR::ABL1) are not broadly available, making it difficult to monitor the patients adequately. Objective: In this sense, providing TFR recommendations for Brazilian physicians are therefore necessary. These recommendations include the main criteria checklist to start the TKIs treatment discontinuing process in patients diagnosed with CML and the population-eligible characteristics for treatment discontinuation. Method: Age, risk score at diagnosis, TKI treatment duration, BCR::ABL1 transcripts type, depth of the molecular response for treatment discontinuation, treatment adherence, patient monitoring and withdrawal syndrome are essential factors to consider in TFR. After TKI discontinuation, BCR::ABL1 transcripts monitoring should be more frequent. When a major molecular response loss is observed during the monitoring of a patient in TFR, the TKI treatment should be resumed. Conclusion: These recommendations should serve as a basis for medical professionals interested in proposing TKI discontinuation for CML patients in clinical practice. It is important to highlight that, despite the benefits of TFR for the patients and the health system, it should only be feasible following the minimum standards proposed in this recommendation.

Respuesta molecular profunda con ponatinib en leucemia mieloide crónica en fase crónica con resistencia a imatinib y dasatinib: Reporte de caso y revisión de la literatura / Profound molecular response with ponatinib in chronic phase of chronic myeloid leukemia with resistance to imatinib and dasatinib: Case report and review of the literature

RESUMEN Se reporta el caso de una mujer quien a la edad de 54 años fue diagnosticada de leucemia mieloide crónica en fase crónica; inició tratamiento con inhibidor de tirosina cinasa de primera generación, y evidenció falla por ausencia de respuesta hematológica y citogenética. A pesar del cambio de tratamiento a un inhibidor de tirosina cinasa de segunda generación (dasatinib), no fue posible alcanzar niveles óptimos de respuesta, documentándose la positividad para la mutación T315I en dominio ABL de la tirosina cinasa desregulada BCR/ABL, frente a la cual el único medicamento que muestra actividad es ponatinib. Luego de iniciar tratamiento con ponatinib, se evidenciaron niveles óptimos de respuesta citogenética y molecular, así como una adecuada calidad de vida de la paciente.

SUMMARY We report the case of a woman who at the age of 54 years was diagnosed with chronic myeloid leukemia in chronic phase; she began treatment with a first-generation tyrosine kinase inhibitor, and evidenced failure due to the absence of a hematological and cytogenetic response. Despite changing treatment to a second-generation tyrosine kinase inhibitor (dasatinib), it was not possible to achieve optimal levels of response, documenting positivity for the T315I mutation in the ABL domain of the deregulated BCR/ABL tyrosine kinase, compared to ponatinib, the only drug that shows activity. After starting treatment with ponatinib, optimal levels of cytogenetic and molecular response were evidenced, as well as an adequate quality of life for the patient.

Leucemia mieloide crónica atípica BCR-ABL1 negativa: reporte de 2 casos / BCR-ABL1 negative chronic myeloid leukemia: report of two cases

BCR-ABL1 negative atypical chronic myeloid leukemia (aCML) is a rare type of myeloproliferative / myelodysplastic syndrome characterized by leukocytosis and proliferation of dysplastic neutrophilic precursors in the absence of positivity for the BCR-ABL1 fusion gene. We report a 66-year-old woman and a 57-year-old man with aCML, who initially presented with general malaise and weight loss, associated with anemia, thrombocytopenia, and leukocytosis with left shift and dysplasia in the neutrophil series. Both evolved unfavorably after admission and died a few days later due to multiple organ failure.

Status and significance of BCR-ABL1 kinase domain mutations in imatinib-resistant chronic myelogenous leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia patients from Northeast China / 白血病·淋巴瘤

Objective:To explore the characteristics of BCR-ABL1 kinase domain mutations in imatinib-resistant chronic myelogenous leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL) patients from Northeast China and their impact on prognosis. Methods:The clinical data of 252 CML patients and 49 Ph + ALL patients who were admitted to the First Hospital of Jilin University from January 2013 to October 2018 were retrospectively analyzed. The samples of bone marrow or peripheral blood were collected from patients when imatinib treatment was not effective. Nested polymerase chain reaction (PCR) was used to amplify the BCR-ABL1 kinase domain, and Sequencing Analysis v5.4 software was used to analyze the mutation of BCR-ABL1 kinase domain. Patients were followed up for 6-48 months, and the survival analysis was performed. Results:Among 252 CML patients, the mutations in ABL1 kinase domain were found in 57 patients (22.6%), including 25 patients in the chronic phase, 21 patients in the accelerated phase and 11 patients in the blast crisis; 50 patients had 20 types of single point mutation, and the most common mutation types were E255K (16.0%, 8/50), T315I (14.0%, 7/50), M244V (8.0%, 4/50) and G250E (8.0%, 4/50), which were all concentrated in the P-loop and C-helix domains; 7 patients had double mutations; patients with multiple mutations had the worst prognosis, with a median overall survival (OS) time of 3.2 months. Among 49 Ph + ALL patients, 17 cases (34.7%) were positive for mutations in the BCR-ABL1 kinase domain, 14 patients had 12 types of single point mutation, and 3 patients had multiple mutations; the median OS time of patients with multiple mutations, mutations located in the P-loop and C-helix domains and mutations located in the other domains was 2.0, 8.0 and 18.0 months, and the difference in OS among the three groups was statistically significant ( P < 0.01). Conclusions:Among the imatinib-resistant CML and Ph + ALL patients from Northeast China, point mutations in the P-loop and C-helix domains are most commonly found. Multiple mutations, mutations in the P-loop and C-helix domains are related to the poor prognosis of the patients.

Progress in molecular resistance mechanisms of targeted therapy for chronic myeloid leukemia / 白血病·淋巴瘤

Resistance or drug-resistant recurrence of targeted tumor therapy is a complex and multi-factorial process, with the final result of tumor clones that can evade treatment or have relative proliferation advantages under treatment pressure being selectively retained. The BCR::ABL1 fusion gene is the primary molecular abnormality of chronic myeloid leukemia (CML), and the development and application of tyrosine kinase inhibitors (TKI) targeting the BCR::ABL1 fusion protein pioneered the era of small molecule targeted therapeutics. Several TKI have been approved for clinical application or in development. Although most CML patients manifest an excellent response to TKI treatment, there are still some patients with poor primary response or relapse with drug resistance. With the increase in the number of patients with long-term maintenance therapy and the sequential use of multiple TKI, the resistance of TKI has become more complicated. This article introduces the research progress of CML molecular resistance mechanisms in recent years and shares the relevant cutting-edge reports at the 63rd American Society of Hematology Annual Meeting in 2021.