Myeloid Blast Crisis Research Articles

RNA-Binding Protein Lin28B Promotes Chronic Myeloid Leukemia Blast Crisis by Transcriptionally Upregulating miR-181d.

The blast crisis (BC) of chronic myeloid leukemia (CML) has poor efficacy against existing treatments and extremely short survival. However, the molecular mechanism of CML-chronic phase (CP) transformation to CML-BC is not yet fully understood. Here, we show that Lin28B, an RNA-binding protein, acted as an activator enhancing the transformation to CML-BC by mediating excessive cell proliferation. The level of Lin28B expression was apparently elevated in patients with CML-BC compared with newly diagnosed patients with CML-CP. The overexpression of Lin28B promoted the proliferation of leukemia cells. Mechanistically, we identified Lin28B as a DNA-binding protein by binding to the promoter region of miR-181d and upregulating its expression, which inhibited the expression of programmed cell death 4 (PDCD4) by binding to the PDCD4 3'UTR region, thereby enhancing the proliferation of CML cells. Overall, the "Lin28B-miR-181d-PDCD4" regulatory axis promoted CML blast crisis. Implications: Our findings highlight the oncogenic role of Lin28B in CML blast crisis, acting as a DNA-binding protein that transcriptionally upregulates miR-181d expression.

Combination therapies with ponatinib and asciminib in a preclinical model of chronic myeloid leukemia blast crisis with compound mutations

Combination therapies with ponatinib and asciminib in a preclinical model of chronic myeloid leukemia blast crisis with compound mutations

Асциминиб у больных хроническим миелолейкозом, не имеющих альтернативных методов лечения: результаты исследования в рамках программы расширенного доступа МАР (Managed Access Program, NCT04360005) в России

Aim. To assess the efficacy and tolerability of asciminib in chronic myeloid leukemia (CML) patients after failure of ≥ 2 lines of tyrosine kinase inhibitors (TKIs) therapy under the МАР (Managed Access Program, NCT04360005) in Russia. Materials & Methods. The study enrolled 68 patients with Ph-positive CML chronic phase (CF), over 18 years of age, after failure of ≥ 2 lines of TKI therapy. The analysis was conducted on data from 50 patients who were followed-up for at least 3 months and did not undergo allo-HSCT. Dosing regimens were prescribed depending on T315I mutation. Asciminib 200 mg per os was administered twice a day to 20 patients with this mutation, and asciminib 40 mg per os was administered twice a day to 30 patients without this mutation. By the time of admission into the MAP, there were 42 (82 %) CF CML patients as well as 8 patients with second CF after accelerated phase (AF, n = 7) and myeloid blast crisis (BC, n = 1). None of them could be treated with any therapeutic alternative. 92 % of patients had received ≥ 3 lines of prior TKI therapy. Overall survival (OS) and discontinuation-free survival were estimated by the Kaplan-Meier method. A cumulative incidence function (CIF) was used to calculate the probability of achieving response. Multivariate analysis was based on Cox regression model. Results. The median asciminib treatment duration was 11 months (range 4–30 months). The probable 2-year OS was 96 %. After 12 and 24 months, discontinuation-free survival was 92 % and 70 %, respectively. On asciminib therapy, complete cytogenetic (CCyR/МR2), major molecular (MMR), and deep molecular (MR4) responses were achieved in 17 (42 %), 14 (30 %), and 9 (19 %) patients who had not responded to prior treatment at the point of enrollment. After completing the 12- and 24-month therapy, the probability of CCyR/МR2 achievement was 44 % and 62 %, that of MMR achievement was 32 % and 40 %, and that of MR4 achievement was 26 % and 37 %, respectively. The patients treated with different doses did not significantly differ in achieving either CCyR/МR2 or MMR. By multivariate analysis, the independently significant factor impacting the probability of achieving MMR on asciminib treatment was the best MR (BCR::ABL1 < 1 % vs. 1–10 % vs. ≥ 10 %) after prior TKI therapy (hazard ratio 7.5873; p = 0.0072). In 22 (44 %) patients, adverse events (AEs) of all grades were observed, and 8 (16 %) patients showed AEs grade 3/4 (predominantly thrombocythemia and neutropenia). None of the patients discontinued asciminib treatment due to AEs. Conclusion. Asciminib demonstrated highly promising efficacy in previously TKI-treated patients with T315I mutation (200 mg BID) and without it (40 mg BID). Asciminib can be regarded as therapeutic option after failure of other TKIs. Different doses of asciminib were equally well tolerated, which makes it applicable for patients with intolerance to other TKIs and also provides ground for considering dose increases in non-responders. Good prospects are also expected for studying asciminib efficacy at earlier treatment stages (in first or second lines) as well as in combination with ATP-binding TKIs in CML patients with insufficient response to TKI treatment.

Dynamic Changes in ABL1 Kinase Domain Mutations and Comparative Efficacy of Third-Generation Tyrosine Kinase Inhibitors across Different Stages in Acute Lymphoblastic Leukemia and Chronic Myeloid Leukemia Blast Crisis Patients

*Drs.Zixuan Li and Danyue Peng contributed equally. Drs.Mei Hong and Qiuling Wu are co-corresponding authors Background The development of first-generation and second-generation tyrosine kinase inhibitors (TKIs) has played a crucial role in the treatment of Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL) and chronic myeloid leukemia (CML). However, the emergence of mutations in the kinase domain (KD) of BCR-ABL1 has increasingly compromised the efficacy of TKIs and become the primary cause of TKI resistance. Testing BCR-ABL1 KD mutations in early phase accurately is of great value in predicting response and guiding therapeutic decisions. Next-generation sequencing (NGS) provided a more comprehensive and elaborate understanding of mutation status. Third-generation (3G) TKI has been designed to overcome resistance problems caused by BCR-ABL1 KD mutations, and it exhibited unique pharmacological profiles and response patterns relative to different mutations and disease characteristics. Therefore, the potential clinical relevance of mutations detected by NGS and the efficacy of 3G TKI are worth exploring. Methods NGS was used to analyze the dynamic changes of both clinically unreported mutations and reported resistant mutations in the ABL1 KD during three stages of the disease course (pretreatment, remission, and relapsed periods) in Ph+ ALL (n = 97) and chronic myeloid leukemia blast crisis (CML-BP) (n = 21) patients. Meanwhile, the comparative efficacy of three generations of TKIs in Ph+ ALL (n = 92) and CML-BP (n = 23) and the relationship between ABL1 KD mutations and different TKI selection were analyzed. Results In Ph+ ALL patients, single ABL1 KD unreported mutations were detected in 30.49% of patients before therapy and 39.73% in remission, which accounted for the highest proportion among other mutation types. Conversely, single ABL1 KD resistant mutations were found to be the most prevalent (54.5%) in relapsed patients ( P < 0.0001). Logistic analysis revealed that the presence of F401V/L in untreated Ph+ ALL patients was associated with a higher risk of relapse ( P < 0.1). Furthermore, through analyzing patients who received TKI treatment, we observed that 3G TKIs like olverembatinib exhibited advantages in prognosis, including achieving deep molecular response, rapid remission reduction, and decreased relapse probability, for both newly diagnosed and relapsed Ph+ ALL patients. Notably, 3G TKIs not only demonstrated strong inhibition against the T315I mutation, as previously reported, but also displayed superior effectiveness against certain ABL1 KD unreported mutations, such as R516L, K262T, and F401V. Similar trends were observed in CML-BP, although statistical significance was not reached likely due to the limited number of patients. Conclusion Overall, our findings indicate the prevalence and impact of ABL1 KD mutations in Ph+ ALL and CML-BP patients, highlighting the necessity for effective therapies targeting these mutations. The promising outcomes observed with 3G TKIs suggest their potential as a treatment option for both newly diagnosed and relapsed Ph+ ALL patients, offering advantages in terms of molecular response depth, rapid remission, and reduced relapse risk. Further investigations are warranted to explore the clinical significance of unreported ABL1 KD mutations and validate the effectiveness of 3G TKIs against them.

T rial of Imatinib after Ponatinib Induction (TIPI) in the Front-Line Treatment of Chronic Phase (CP) Chronic Myeloid Leukemia (CML) Setting. Report of the First Therapeutic Sequence

Introduction: The prevention ofdisease transformation which typically occurs during the first years of treatment, is one of the critical goals of the treatment of CP-CML with TKI. In addition, treatment free remission (TFR) represents now another major challenge. In vitro data show that ponatinib is one of the most powerful inhibitors of wild-type as well as mutated BCR::ABL1 TK and this has been translated in heavily pre-treated CML patients (pts) intolerant or resistant to other compounds. In this trial we assessed the safety and efficacy of a 6-months debulking strategy using ponatinib as front-line therapy in newly diagnosed CP-CML, followed by a maintenance with imatinib, in order to bring a high proportion of pts in TFR. Methods: This open-label phase II national academic trial (Clinical Trial: NCT04070443) enrolled newly diagnosed adult CP-CML pts ≤65 years, with a major BCR::ABL1 transcript and no significant underlying cardio-vascular disease, uncontrolled hypertension or diabetes with target organ damage, QTc prolongation and with adequate organ functions. They were stratified according to the ELTS score. The primary endpoint is the impact of ponatinib induction on the rate of pts reaching TFR criteria as defined by our group (Rea et al. Cancer, 2018) at M36. Secondary endpoints were the safety and clinical activity of this strategy, ponatinib pharmacokinetics (PK), QoL under both inhibitors and compliance. Pts were treated with ponatinib 30 mg QD for 6-months, followed by imatinib 400 mg QD until TFR criteria (i. e. MR4.5 ≥2 years) would been reached before M60. All molecular assessments were centralised and BCR::ABL1 transcripts were expressed in % on the international scale (IS). This analysis relies on the intention-to-treat principle. Results: One hundred and seventy-eight pts were screened, 170 enrolled and 169 treated between November 2019 and October 2022. Median age was 48 (18-65) years, 113 pts were males (67%). One pt had a cryptic Ph, and 15 (9%) pts harboured additional chromosomal abnormalities (ACA). Eighty-four (51.5%) pts had b2a2 and 99 (61%) b3a2 transcripts knowing that they could harbour both. ELTS were low for 67 (40%) pts, intermediate for 73 (44%) and high for 27 (16%). For 2 patients it could not be calculated (1 splenectomy, 1 no spleen assessment). European Society of Cardiology (ESC) score was <2% in 158/167 (93%) evaluable pts, 3-9% in 8 (5%) pts and >10% in 1 (2%) pt. One hundred and one (60%) pts never smoked, 46 (27%) were past smokers. The median follow-up at database lock was 18 (3-33) months. Only induction data are presented here. The median number of days on ponatinib is 172 (1-193) and the median dose of ponatinib delivered is 30 (16.5-32) mg daily. Overall, 135 grade 3-5 AEs occurred after a median of 51 (0-186) days: 123 (91%) grade 3, 11 (8%) grade 4 and 1 fatal AE; 49 (36%) were hematologic, and 86 (64%) non-hematologic, and 109 (81%) were considered as related to study treatment. Seven pts (5%) discontinued permanently ponatinib, and 56 (41.5%) received the full planned dose. Six (4.5%) Grade 3-5 cardiac events (1 fatal cardiac arrest) and 17 (12.5%) vascular events (15 newly hypertensive pts, 1 pulmonary embolism? 1 carotid stenosis) occurred. Their cumulative incidence is shown in Figure 1A. Digestive & clinical hepato-biliary events occurred in 10 (7.5%), infections in 7 (5%), lipase elevation in 15 (11%) and liver enzymes elevation in 20 (15%) pts. Eye, skin and neurologic events occurred in less than 2% of pts. Regarding efficacy, 147 evaluable pts/158 (93%) were in CHR at M1, 115 in CCyR (70.5%) at M3 and 158/163 (97%) in EMR. The median halving time (calculated with ABL1 as a reference gene) was 13.5 (11.5-17.5) days. The cumulative incidence of molecular response is shown in Figure 1B. Fourty-seven pts over 157 assessable (30%) were in deep molecular response at M6. One (0.6%) pt transformed into myeloid blast crisis, alive in CR before transplant. PK data and their relationship with safety and efficacy will be presented. Univariate analysis identified the halving time as the only factor impacting on MR4.5 at M6. Conclusions: Ponatinib displays high anti-leukemic activity as front-line therapy in selected newly diagnosed CP-CML pts with high early molecular response rates with non-negligible severe -in particular cardio-vascular- toxicity at 30 mg QD. Whether or not this will be translated into substantial TFR rates will be determined at later time points.

The role of flow cytometry in the classification of myeloid disorders.

The World Health Organization classification (WHO-HAEM5) and the International Consensus Classification (ICC 2022) of myeloid neoplasms are based on the integration of clinical, morphologic, immunophenotypic, and genomic data. Flow cytometric immunophenotyping (FCIP) allows the identification, enumeration, and characterization of hematopoietic cells, and is therefore apowerful tool in the diagnosis, classification, and monitoring of hematological neoplasms. The vast majority of flow cytometry (FCM) studies in chronic myeloid neoplasms focus on its role in myelodysplastic neoplasms (MDS). FCM can also be helpful for the assessment of myeloproliferative neoplasms (MPN) and MDS/MPN, including the early detection of evolving myeloid or lymphoid blast crisis and the characterization of monocytic subsets. The classification of acute myeloid leukemia (AML) is primarily based on cytogenetic and molecular findings; however, FCIP is needed for subclassification of AML, not otherwise specified (NOS; ICC)/AML defined by differentiation (WHO-HAEM5). The main role of FCM in AML remains in making arapid diagnosis and as atool for measurable residual disease monitoring. Machine learning and artificial intelligence approaches can be used to analyze and classify FCM data. This article, based on an invited lecture at the 106th Annual Meeting of the German Society of Pathology in 2023, reviews the role of FCM in the classification of myeloid neoplasms, including recent publications on the application of artificial intelligence.

A Phase I/II Study to Investigate the Addition of Venetoclax to Dasatinib and Steroids in Patients with Newly Diagnosed or Relapsed Philadelphia Chromosome Positive Acute Lymphoblastic Leukemia (Ph+ ALL): The Venda Trial, in Progress

Background: Acute Lymphoblastic Leukemia (ALL) is a hematologic malignancy of immature lymphocytes of either B cell or T cell origin. One particularly high -risk subset is Ph+ ALL, characterized by a translocation of chromosome 9 and 22, which generates the constitutively active BCR-ABL1 fusion tyrosine kinase capable of driving proliferation and survival of leukemic cells. Currently treatment options include multi-agent chemotherapy along with an ABL-specific tyrosine kinase inhibitor (TKI), though these regimens can lead to significant toxicity, particularly in older adults. Venetoclax is a potent and selective small molecule inhibitor of the B-cell lymphoma 2 (BCL-2) anti-apoptotic protein. Strong mechanistic and preclinical data have demonstrated strong synergistic activity between dasatinib and venetoclax I xenograft models and ex vivo patient samples, and provide an impetus to further explore the combination of BCR-ABL and BCL-2 inhibition in vivo. Based on these data, we designed a clinical trial to investigate the safety and preliminary efficacy of venetoclax in combination with the second generation TKI dasatinib in Ph+ ALL. Study Design and Methods This is an open label, Phase I/II investigator initiated trial evaluating the addition of venetoclax to dasatinib and steroids (with Rituximab in CD20+ patients). Phase I is the safety and dose-finding portion of the trial combining the BCL2 inhibitor venetoclax with dasatinib and steroids during the first 28 days of induction followed by dasatinib and venetoclax for the final 48 days of induction in newly diagnosed and relapsed Ph+ ALL and mixed phenotype acute leukemia (MPAL) patients, including patients with molecular only relapse. Primary inclusion criteria include a histologically confirmed diagnosis of Ph+ ALL or MPAL. Newly diagnosed Ph+ ALL or MPAL patients may not have received leukemia-directed therapy other than for steroids or hydrea, and relapsed patients must have not had prior dasatinib exposure. Key exclusion criteria include subjects with CML in myeloid blast crisis or Ph+ AML, ECOG < 2 and patients with a history of pleural effusions. n order to determine the maximum tolerated dose (MTD) and/or recommended phase 2 dose (RP2D), a Bayesian toxicity probability interval design applied to a pre-specified targeted dose limiting toxicity rate of 30%. Three dose cohorts investigating increasing doses of venetoclax will be enrolled. Once the RP2D dose has been identified, a Phase II expansion will examine preliminary efficacy of the combination. The primary endpoint is the rate of measureable residual disease (MRD) negative remission rate as assessed by both BCR-ABL RT-PCR and next generation sequencing (NGS) after induction. Secondary endpoints include relapse-free survival (RFS) and overall survival (OS). Correlative studies include BH3 profiling (measure of apoptosis) and ex vivo screening to dasatinib and venetoclax alone and in combination. Consolidation phase with blinatumomab plus dasatinib and venetoclax is planned for the cohort expansion group. Enrollment began in September 2022 and is expected to be complete by September 2025. This trial is registered at clinicaltrials.gov (NCT04872790).

Secondary acute myeloid leukemia and de novo acute myeloid leukemia with myelodysplasia-related changes - close or complete strangers?

To compare the main features of patients with secondary acute myeloid leukemias (AMLs) after post-myelodysplastic syndrome (AML-post-MDS) or post-myeloproliferative neoplasms (AML-post-MPN) and myeloid blast crisis of chronic myeloid leukemia (CML-BC) vs. de novoAMLs with myelodysplastic characteristics (dn-AML-MDS).

Deciphering Potential Molecular Signatures to Differentiate Acute Myeloid Leukemia (AML) with BCR::ABL1 from Chronic Myeloid Leukemia (CML) in Blast Crisis.

Acute myeloid leukemia (AML) with BCR::ABL1 has recently been recognized as a distinct subtype in international classifications. Distinguishing it from myeloid blast crisis chronic myeloid leukemia (BC-CML) without evidence of a chronic phase (CP), remains challenging. We aimed to better characterize this entity by integrating clonal architecture analysis, mutational landscape assessment, and gene expression profiling. We analyzed a large retrospective cohort study including CML and AML patients. Two AML patients harboring a BCR::ABL1 fusion were included in the study. We identified BCR::ABL1 fusion as a primary event in one patient and a secondary one in the other. AML-specific variants were identified in both. Real-time RT-PCR experiments demonstrated that CD25 mRNA is overexpressed in advanced-phase CML compared to AML. Unsupervised principal component analysis showed that AML harboring a BCR::ABL1 fusion was clustered within AML. An AML vs. myeloid BC-CML differential expression signature was highlighted, and while ID4 (inhibitor of DNA binding 4) mRNA appears undetectable in most myeloid BC-CML samples, low levels are detected in AML samples. Therefore, CD25 and ID4 mRNA expression might differentiate AML with BCR::ABL1 from BC-CML and assign it to the AML group. A method for identifying this new WHO entity is then proposed. Finally, the hypothesis of AML with BCR::ABL1 arising from driver mutations on a BCR::ABL1 background behaving as a clonal hematopoiesis mutation is discussed. Validation of our data in larger cohorts and basic research are needed to better understand the molecular and cellular aspects of AML with a BCR::ABL1 entity.

CML with De Novo NPM1 Mutation and Rapid Progression to Myeloid Blast Cri-Sis despite Treatment with Imatinib: A Case Report

In this case we present a 41 year old male with chronic myeloid leukaemia who despite scoring low risk for Sokal progressed rapidly to blast crisis without warning and after having achieved a partial response to Imatinib therapy. We investigated using retrospective Next Generation Sequencing (NGS) and identified a novel NPM1 mutation at diagnosis and blast crisis together. We also found tyrosine kinase domain mutations using NGS not found with Sanger sequencing. We believe this case highlights the effectivity of NGS in identifying novel and existing mutations with higher sensitivity, which could help improve existing practice in prognostication and management of CML disease in patients not responding to treatment adequately.

Core-binding factor fusion downregulation of ADAR2 RNA editing contributes to AML leukemogenesis

AbstractAdenosine-to-inosine RNA editing, which is catalyzed by adenosine deaminases acting on RNA (ADAR) family of enzymes, ADAR1 and ADAR2, has been shown to contribute to multiple cancers. However, other than the chronic myeloid leukemia blast crisis, relatively little is known about its role in other types of hematological malignancies. Here, we found that ADAR2, but not ADAR1 and ADAR3, was specifically downregulated in the core-binding factor (CBF) acute myeloid leukemia (AML) with t(8;21) or inv(16) translocations. In t(8;21) AML, RUNX1-driven transcription of ADAR2 was repressed by the RUNX1-ETO additional exon 9a fusion protein in a dominant-negative manner. Further functional studies confirmed that ADAR2 could suppress leukemogenesis specifically in t(8;21) and inv16 AML cells dependent on its RNA editing capability. Expression of 2 exemplary ADAR2-regulated RNA editing targets coatomer subunit α and component of oligomeric Golgi complex 3 inhibits the clonogenic growth of human t(8;21) AML cells. Our findings support a hitherto, unappreciated mechanism leading to ADAR2 dysregulation in CBF AML and highlight the functional relevance of loss of ADAR2-mediated RNA editing to CBF AML.

Pediatric chronic myeloid leukemia in myeloid blast crisis

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.

Acquired Factor VII Deficiency Associated With Chronic Myeloid Leukemia Blast Crisis.

Factor VII (FVII) is an important, vitamin K-dependent clotting factor. Acquired FVII deficiency is a rare entity that is associated with serious bleeding complications. We report a case of acquired FVII deficiency in a patient with recurrent chronic myeloid leukemia in blast crisis who developed bilateral retinal hemorrhages. The coagulopathy was corrected with the initiation of chemotherapy and subsequent reduction in peripheral blast count.

Blast crisis in chronic myeloid leukemia: An immunophenotypic analysis

Background and Aim of Study: There are two different phases of untreated chronic myeloid leukemia – chronic phase, and blast crisis – according to the World Health Organization classification of Hematolymphoid tumors. The blast cells in the chronic myeloid leukemia blast crisis can express myeloid, lymphoid, bi-phenotypic, monocytic, megakaryocytic, and erythroid phenotypes. The immunophenotype of blast population determines how chronic myeloid leukemia – blast crisis patients respond to treatment, hence flowcytometric examination is required. The aim of the study: to assess immunophenotyping outcomes of flowcytometry performed on the chronic myeloid leukemia – blast crisis. Material and Methods: A five-year retrospective descriptive analysis was carried out in Pathology Department at King George’s Medical University Lucknow, India (2017-2021). The patient’s peripheral blood and bone marrow aspirate samples were analyzed. Clinical, hematological, and immunophenotypic data were retrieved. The flow cytometry samples were prepared using the standardized “lyse-stain-wash” method. Results: A total of 43 cases of chronic myeloid leukemia – blast crisis were retrieved from the departmental archive in 5 years. The mean age of study population was 39.62±14.86 years. There were 24 males and 19 females. 27 patients were diagnosed with myeloid blast crisis, 14 cases of B-lymphoid blast crisis and 2 cases of mixed phenotypic acute leukemia. Conclusions: Identification of the blast lineage of patients with chronic myeloid leukemia – blast crisis is crucial since the existence of atypical blast phenotypes influences the disease treatment and prognosis.

Molecular genetic characterization of Philadelphia chromosome-positive acute myeloid leukemia

BackgroundPhiladelphia chromosome-positive acute myeloid leukemia (Ph+ AML) is a provisional disease entity in the 2016 WHO classification, while its genetic profile of Ph+ AML remains poorly defined. In addition, the differentiating features of Ph+ AML and chronic myeloid leukemia in myeloid blast crisis (CML-MBC) remain controversial. MethodsWe conducted a retrospective study of 15 Ph+ AML patients to compare their clinical and laboratory profiles with 27 CML-MBC patients. ResultsCompared to CML-MBC, Ph+ AML patients presented with significantly higher peripheral WBC count and bone marrow blast percentage. The immunophenotypic profiles were largely similar between Ph+ AML and CML-MBC, except for CD4 expression, which was significantly enriched in CML-MBC. Ph+ AML patients less frequently harboured co-occurring additional cytogenetic abnormalities (ACA) compared to CML-MBC, and trisomy 19 (23%) and IDH1/2 (46%) were the most common ACA and mutated genes in Ph+ AML, respectively. Overall survival (OS) did not significantly differ between Ph+ AML and CML-MBC. Ph+ AML without CML-like features appeared to have a better outcome compared to Ph+ AML with CML-like features; ACA in Ph+ AML may confer an even worse prognosis. ConclusionsOur results indicate that patients with Ph+ AML share similar genetic profiles and clinical outcomes with those with CML-MBC, thus should be classified as a high-risk entity.

Molecular Aberrations in Acute Myeloid Leukemia (AML) and Myelodysplastic Syndrome with Excess Blast II (MDS-EB II) in Kuwait

Introduction: AML is a heterogeneous disease. Different mutational profiles have been described and correlate with variable outcomes. Genetic abnormalities are not well-described in our region. Our aim is to describe the molecular aberrations observed in the first cohort of patients. We recently introduced DNA based Oncomine Myeloid Gene Panel testing 55 genes. Method: we collected clinical, cytogenetic and molecular data prospectively since we introduced the test in late 2020. We also reviewed medical charts to collect baseline clinical data. We included patients aged 16 yrs and above with AML or MDS-EB II treated at Kuwait Cancer Center. Results: fifty-seven patients were included in the study with median age of 51 yrs. Almost one third of the patients were Kuwaitis (36%). Baseline demographic described in (table 1). We have 53 patients with AML (92%), 3 patients with MDS-EB II (5%) and 1 pt with chronic myeloid leukemia in myeloid blast crisis (CML-MBC). Most of the patients had at least one mutation (91%) detected by the panel. The most common mutations (figure1) were FLT3 (ITD & D835) detected 26.3%, followed by NPM-1 detected in 21%. We have noticed an increased PTPN11 mutation, detected in 17.5% of the cases. Conclusion: This is an important study showing extensive molecular abnormalities in AML patients in the region. This will facilitate more understanding of the disease biology and potentially guide therapeutic options

Histone chaperone ASF1A accelerates chronic myeloid leukemia blast crisis by activating Notch signaling

The blast crisis (BC) is the final deadly phase of chronic myeloid leukemia (CML), which remains a major challenge in clinical management. However, the underlying molecular mechanism driving blastic transformation remains unclear. Here, we show that ASF1A, an essential activator, enhanced the transformation to CML-BC by mediating cell differentiation arrest. ASF1A expression was aberrantly increased in bone marrow samples from CML-BC patients compared with newly diagnosed CML-chronic phase (CP) patients. ASF1A inhibited cell differentiation and promoted CML development in vivo. Mechanistically, we identified ASF1A as a coactivator of the Notch transcriptional complex that induces H3K56ac modification in the promoter regions of Notch target genes, and subsequently enhanced RBPJ binding to these promoter regions, thereby enhancing Notch signaling activation to mediate differentiation arrest in CML cells. Thus, our work suggests that targeting ASF1A might represent a promising therapeutic approach and a biomarker to detect disease progression in CML patients.

AML-419 Molecular Aberrations in Acute Myeloid Leukemia (AML) and Myelodysplastic Syndrome With Excess Blast II (MDS-EB II) in Kuwait

AML is a heterogeneous disease. Different mutational profiles have been described and correlate with variable outcomes. Genetic abnormalities are not well-described in our region. Our aim is to describe the molecular aberrations observed in the first cohort of patients. We recently introduced DNA based Oncomine Myeloid Gene Panel, testing 55 genes. We collected clinical, cytogenetic and molecular data prospectively since we introduced the test in late 2020. We also reviewed medical charts to collect baseline clinical data. We included patients aged 16 yrs and above with AML or MDS-EB II treated at Kuwait Cancer Center. Fifty-seven patients were included in the study with median age of 51 yrs. Almost one third of the patients were Kuwaitis (36%). We have 53 patients with AML (92%), 3 patients with MDS-EB II (5%), and 1 patient with chronic myeloid leukemia in myeloid blast crisis (CML-MBC). Most of the patients had at least one mutation (91%) detected by the panel. The most common mutations were FLT3 (ITD & D835), detected 26.3%, followed by NPM-1, detected in 21%. We have noticed an increased PTPN11 mutation, detected in 17.5% of the cases. This is an important study showing extensive molecular abnormalities in AML patients in the region. This will facilitate more understanding of the disease biology.

Integrated genomic sequencing in myeloid blast crisis chronic myeloid leukemia (MBC-CML), identified potentially important findings in the context of leukemogenesis model

Chronic myeloid leukemia (CML) is a model of leukemogenesis in which the exact molecular mechanisms underlying blast crisis still remained unexplored. The current study identified multiple common and rare important findings in myeloid blast crisis CML (MBC-CML) using integrated genomic sequencing, covering all classes of genes implicated in the leukemogenesis model. Integrated genomic sequencing via Whole Exome Sequencing (WES), Chromosome-seq and RNA-sequencing were conducted on the peripheral blood samples of three CML patients in the myeloid blast crisis. An in-house filtering pipeline was applied to assess important variants in cancer-related genes. Standard variant interpretation guidelines were used for the interpretation of potentially important findings (PIFs) and potentially actionable findings (PAFs). Single nucleotide variation (SNV) and small InDel analysis by WES detected sixteen PIFs affecting all five known classes of leukemogenic genes in myeloid malignancies including signaling pathway components (ABL1, PIK3CB, PTPN11), transcription factors (GATA2, PHF6, IKZF1, WT1), epigenetic regulators (ASXL1), tumor suppressor and DNA repair genes (BRCA2, ATM, CHEK2) and components of spliceosome (PRPF8). These variants affect genes involved in leukemia stem cell proliferation, self-renewal, and differentiation. Both patients No.1 and No.2 had actionable known missense variants on ABL1 (p.Y272H, p.F359V) and frameshift variants on ASXL1 (p.A627Gfs*8, p.G646Wfs*12). The GATA2-L359S in patient No.1, PTPN11-G503V and IKZF1-R208Q variants in the patient No.3 were also PAFs. RNA-sequencing was used to confirm all of the identified variants. In the patient No. 3, chromosome sequencing revealed multiple pathogenic deletions in the short and long arms of chromosome 7, affecting at least three critical leukemogenic genes (IKZF1, EZH2, and CUX1). The large deletion discovered on the short arm of chromosome 17 in patient No. 2 resulted in the deletion of TP53 gene as well. Integrated genomic sequencing combined with RNA-sequencing can successfully discover and confirm a wide range of variants, from SNVs to CNVs. This strategy may be an effective method for identifying actionable findings and understanding the pathophysiological mechanisms underlying MBC-CML, as well as providing further insights into the genetic basis of MBC-CML and its management in the future.

CYTOLOGICAL DIAGNOSIS OF CUTANEOUS MYELOID SARCOMA-A RARE CASE REPORT

Introduction: Granulocytic sarcoma or myeloid sarcoma also known as chloroma is a rare extramedullary tumour which may occur as a manifestation of acute myeloid leukaemia, myelodysplastic syndrome or blast crisis in chronic myeloproliferative disorder or may precede systemic leukaemia. Most common site includes skin, soft tissue and lymph nodes. Orbit is most commonly involved in paediatric age group. Case Report: A case of 51 years old female was admitted in department of haematology, presented with multiple nodules in nasal cavity, forehead, bilateral arms and whole abdomen. Bone marrow aspiration cytology shows 21% myeloid blast with transformation of the CML to AML.FNAC was done from multiple nodules which showed plenty of myeloid precursors and blast and diagnosis of granulocytic sarcoma was given. BCR-ABL study came out positive and karyotyping for haematological malignancy showed t (5; 12)(q31;24.3). Patient was given chemotherapy, but showed no improvement. Conclusion: Granulocytic sarcoma (GS) is a rare malignant solid tumour in adults. Diagnosis of GS has been a problem for pathologist because of relatively immature nature of tumour cells and mostly misdiagnosed as Non Hodgkin's lymphoma. Diagnosis of GS is considered as an adverse prognostic factor but early conrmation of diagnosis and treatment initiation might improve the prognosis.