Flow cytometry in acute myeloid leukemia and detection of minimal residual disease.

Acute myeloid leukemia (AML) is a common type of acute leukemia (AL), belonging to malignant tumors of the hematopoietic system with the characteristics of rapid disease development, control with extreme difficulties, easy recurrence, poor prognosis, and incidence rate increasing with age. The traditionally diagnostic standard of French American British (FAB), being based on the morphological examination with high human subjectivity, can no longer meet the demand of clinical diagnosis and treatment of AML. Requirements of objective accuracy and low-dose sample, have become the indispensable method for AML diagnosis and monitoring prognosis. Flow cytometry is a modern technology that can quickly and accurately detect the series, antigen distribution, differentiation stage of AML cells, minimal residual lesions after AML therapy, so as to provide the great significance in guiding clinical diagnosis, hierarchical treatment, and prognosis judgement. This article will systematically elaborate on the application of flow cytometry in the diagnosis and classification of AML, and the detection of minimal residual lesions, thereby providing reference significance for dynamic monitoring and prognostic observation of AML with different immune subtypes of FAB.

Acute promyelocytic leukemia: A rare presentation without systemic disease.

Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia characterized by an abnormal proliferation of promyelocytes. It is often associated with an aggressive clinical presentation involving complex coagulopathies including disseminated intravascular coagulation, with a significant risk of bleeding and/or thrombosis if treatment with all-trans-retinoic acid (ATRA) is not rapidly initiated. Here we present a unique case of APL which was isolated to femoral bone lesions, without definitive evidence of peripheral blood or bone marrow involvement, and without systemic sequelae.

Case report: Combination therapy with selinexor, decitabine and half-dose CAG regimen for relapsed elderly acute myeloid leukemia.

The treatment of elderly patients diagnosed with acute myeloid leukemia (AML) poses significant challenges. Currently, one promising strategy in therapeutic interventions for geriatric individuals revolves around the utilization of small molecule targeted drugs either independently or in conjunction with demethylating agents. In this report, we present the successful attainment of complete remission in an elderly female patient with relapsed AML, the patient underwent treatment with a combination of Selinexor, decitabine, and a half-dose CAG regimen for two cycles. Subsequently, the patient has sustained this remission through consolidation therapy involving a medium dose of Ara-c. This therapeutic regimen has demonstrated favorable outcomes in the management of relapsed AML in elderly individuals. Furthermore, the adverse reactions were manageable. In order to devise an efficacious treatment regimen for elderly patients suffering from relapsed and refractory acute myeloid leukemia, it is imperative to incorporate a larger cohort of cases for clinical investigation.

Acute myeloid leukemia cells adhere to bone marrow and acquire chemoresistance by downregulating UNC5B expression.

Acute myeloid leukemia (AML) is a malignant tumor of the hematological system. Because of its characteristics of recurrence, refractory and chemoresistance, new therapeutic targets need to be identified. Adhesion and proliferation are characteristics of AML cells, and critical steps in inducing chemotherapy resistance. In this study, we reported that UNC5B inhibits AML cell bone marrow adhesion, inhibits AML cell proliferation and increases sensitivity to chemotherapy. Mechanistically, RNA sequencing (RNA-seq) and experimental results revealed that overexpression of UNC5B inhibits adhesion and proliferation signaling pathways and inhibits the expression of MPZL1, CLDN23, IGF2 and WNT7B. In conclusion, our findings suggest that UNC5B serves as a prognostic indicator and a potential therapeutic target for AML.

Efficacy and safety of CAR-T therapy targeting CLL1 in patients with extramedullary diseases of acute myeloid leukemia.

BACKGROUNDS: The incidence of extramedullary diseases (EMDs) in patients diagnosed with acute myeloid leukemia (AML) is approximately 10-20%. These patients exhibit a significantly distinct etiology, therapeutic response, and prognosis compared to patients without EMDs. CLL1 CAR-T therapy has been demonstrated satisfactory efficacy and safety in the treatment of refractory and relapsed AML patients. However, concerns have been raised regarding the potential impact of extramedullary niduses on the effectiveness of CLL1 CAR-T therapy. METHODS: A total of 47 patients were enrolled in this study, including 27 patients with isolated AML tumor bone marrow infiltration and 20 patients with both extramedullary and bone marrow infiltration of AML. CLL1 CAR-T cells were manufactured and subjected to rigorous quality control in the hematology laboratory of Tianjin First Central Hospital. The efficacy and adverse reactions were assessed following CAR-T cell infusion, while expansion of CAR-T cells, levels of cytokines releasing, and other indicators were closely monitored. RESULTS: Among the 20 patients with EMDs and the 27 individuals without EMDs, complete remission in bone marrow was achieved by 65.00% and 81.48% of patients, respectively. Meanwhile, among the patients with EMDs, 55.00% achieved complete remission while 10.00% achieved partial remission when assessing the efficacy of CLL1 CAR-T cells against extramedullary niduses. Although the overall survival, progression-free survival, and duration of remission period appeared to be shorter for patients with EMDs compared to those without EMDs, this difference did not reach statistical significance. The incidence rates of complications were comparable between both groups. Meanwhile, there were no significant differences observed in the levels of CAR-T cell expansion and accompanying cytokines release between patients with and without EMDs. CONCLUSIONS: Our study findings have demonstrated the efficacy of CLL1 CAR-T therapy in the treatment of AML patients with EMDs, while also indicating manageable occurrence rates of complications within a tolerable range. The CLL1 CAR-T therapy, serving as an ideal strategy for AML patients irrespective of the presence of EMDs, effectively ameliorates the conditions of AML patients and provides them with an opportunity to undergo curative hematopoietic stem cell transplantation while significantly enhancing their prognosis.

Sorafenib maintenance after allogeneic stem cell transplantation in patients with FLT3+ AML receiving midostaurin during induction and consolidation: a retrospective analysis.

Introduction: Acute myeloid leukemia (AML) relapse is the main cause of death after allogeneic stem cell transplant (allo-SCT). In AML FLT3+, it was shown that Sorafenib used as maintenance therapy after allo-SCT, significantly reduces the risk of relapse and death. Methods: We analyzed 29 adult patients with FLT3m AML and underwent allogeneic stem cell transplant from 2019 to 2023. All patients received midostaurin plus conventional CT during induction and consolidation. After transplantation, Sorafenib maintenance was administered in all patients independently from MRD status at transplantation. Results: Sorafenib maintenance was applied in 18 patients out 29 patients (62%). Median time to start sorafenib was 100 days (range 37-225) and median duration of treatment was 775 days (range 140-1064). For the whole population (n=29), 2-year OS, LFS, and CIR was 76%, 68% and 28%, respectively. The median time to relapse was 137 days (range 49-246). For patients treated with sorafenib (n=18), the 2-year OS, LFS, and CIR were 94%, 84% and 11%, respectively. For the whole population, the 100-day NRM was 0% and 1-year NRM was 3%. Death was caused by transplant-associated thrombotic microangiopathy in 1 patient. For patients who were administered with Sorafenib, the 1-y NRM was 5%. Death was caused by transplant associated transplant-associated thrombotic microangiopathy. Discussion: This retrospective study suggests that sorafenib maintenance seem to be effective even in patients pre-treated with midostaurin.

Obesity Promotes the Ceramide-Mediated NADPH Oxidase in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a type of blood cancer of the myeloid cell lineage. Obesity is characterized by an increase in body weight that results in excessive fat accumulation. Obesity has been associated with an increased incidence of many cancers, including blood cancers. This study evaluated the role obesity in AML progression in a novel transgenic mouse model developed by crossing Flt3ITD mice with Lepob/ob mice. Leukemia burden was augmented in obese AML mice. In addition, it was determined that obesity upregulated the ceramide-mediated and ceramide-1-phosphate-mediated NADPH oxidase 2 (NOX2). Notably, increased oxidative pathways has been attributed to disease progression in AML. Taken together, this study demonstrates a direct link between obesity and the progression of AML in part by augmenting the ceramide mediated NOX2.

Immunotherapeutic Potential of Mutated NPM1 for the Treatment of Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a malignant disease of the blood and bone marrow that is characterized by uncontrolled clonal proliferation of abnormal myeloid progenitor cells. Nucleophosmin 1 (NPM1) gene mutations are the most common genetic abnormality in AML, detectable in blast cells from about one-third of adults with AML. AML NPM1mut is recognized as a separate entity in the World Health Organization classification of AML. Clinical and survival data suggest that patients with this form of AML often have a more favorable prognosis, which may be due to the immunogenicity created by the mutations in the NPM1 protein. Consequently, AML with NPM1mut can be considered an immunogenic subtype of AML. However, the underlying mechanisms of this immunogenicity and associated favorable survival outcomes need to be further investigated. Immune checkpoint molecules, such as the programmed cell death-1 (PD-1) protein and its ligand, PD-L1, play important roles in leukemogenesis through their maintenance of an immunosuppressive tumor microenvironment. Preclinical trials have shown that the use of PD-1/PD-L1 checkpoint inhibitors in solid tumors and lymphoma work best in novel therapy combinations. Patients with AML NPM1mut may be better suited to immunogenic strategies that are based on the inhibition of the PD-1 immune checkpoint pathway than patients without this mutation, suggesting the genetic landscape of patients may also inform best practice for the use of PD-1 inhibitors.

Corrigendum: Quantitative Dixon and intravoxel incoherent motion diffusion magnetic resonance imaging parameters in lumbar vertebrae for differentiating aplastic anemia and acute myeloid leukemia.

[This corrects the article DOI: 10.3389/fonc.2023.1277978.].

Identification of ANXA1 as a Novel Upstream Negative Regulator of Notch1 Function in AML.

Abnormal Notch1 expression has an important role in tumorigenesis. However, upstream control mechanisms for Notch1 are still insufficiently understood. Acute myeloid leukemia (AML) is one of the most common and lethal blood malignancies with limited possibilities for treatment. Thus, new therapeutic targets are urgently needed to improve current ineffective therapies. Herein, high Annexin A1 (ANXA1) expression is found correlated with hyperproliferation of AML cells, and then ANXA1 is identified as a novel negative regulator of Notch1 function in AML. Mechanistically, ANXA1 directly bound to the intracellular domain of Notch1 (NICD) to target this tumor suppressor for degradation. Furthermore, NICD executed its tumor suppressive function through activation of the p15 promoter. Thus, ablation of the Notch1-p15-mediated tumor suppression by ANXA1 provided a novel mechanism of AML proliferation. In human AML patients, a mutual exclusive relation is discovered between ANXA1 and Notch1/p15, corroborating mechanistic discovery. On the basis of these results, it is reasonably speculated that targeting ANXA1 would provide an effective approach for treatment of AML. In support of this new therapeutic paradigm, provided proof-of-concept data by antagonizing ANXA1 using NICD inhibitory peptides.

Modelling post-chemotherapy stem cell dynamics in the bone marrow niche of AML patients.

Acute myeloid leukemia (AML) is a stem cell-driven malignancy of the blood forming (hematopoietic) system. Despite of high dose chemotherapy with toxic side effects, many patients eventually relapse. The "7+3 regimen", which consists of 7 days of cytarabine in combination with daunorubicin during the first 3 days, is a widely used therapy protocol. Since peripheral blood cells are easily accessible to longitudinal sampling, significant research efforts have been undertaken to characterize and reduce adverse effects on circulating blood cells. However, much less is known about the impact of the 7+3 regimen on human hematopoietic stem cells and their physiological micro-environments, the so-called stem cell niches. One reason for this is the technical inability to observe human stem cells in vivo and the discomfort related to bone marrow biopsies. To better understand the treatment effects on human stem cells, we consider a mechanistic mathematical model of the stem cell niche before, during and after chemotherapy. The model accounts for different maturation stages of leukemic and hematopoietic cells and considers key processes such as cell proliferation, self-renewal, differentiation and therapy-induced cell death. In the model, hematopoietic (HSCs) and leukemic stem cells (LSCs) compete for a joint niche and respond to both systemic and niche-derived signals. We relate the model to clinical trial data from literature which longitudinally quantifies the counts of hematopoietic stem like (CD34+CD38-ALDH+) cells at diagnosis and after therapy. The proposed model can capture the clinically observed interindividual heterogeneity and reproduce the non-monotonous dynamics of the hematopoietic stem like cells observed in relapsing patients. Our model allows to simulate different scenarios proposed in literature such as therapy-related impairment of the stem cell niche or niche-mediated resistance. Model simulations suggest that during the post-therapy phase a more than 10-fold increase of hematopoietic stem-like cell proliferation rates is required to recapitulate the measured cell dynamics in patients achieving complete remission. We fit the model to data of 7 individual patients and simulate variations of the treatment protocol. These simulations are in line with the clinical finding that G-CSF priming can improve the treatment outcome. Furthermore, our model suggests that a decline of HSC counts during remission might serve as an indication for salvage therapy in patients lacking MRD (minimal residual disease) markers.

Unusual Presentation of Myeloid Sarcoma as Thigh Mass.

INTRODUCTION: Myeloid sarcoma (MS) is a tumor containing myeloid blasts, with or without maturation, involving any anatomical site other than the bone marrow. It can occur de novo or following a hematological malignancy. CASE: We report a 6-year-old female who presented with fever and a rapidly enlarging left thigh mass. The initial provisional diagnosis considered was tubercular hip arthritis with an abscess, but imaging investigations suggested neoplastic swelling. A biopsy of the mass showed a malignant small-round cell tumor. Bone marrow aspiration revealed the diagnosis of acute myeloid leukemia without the presence of blasts in the peripheral smear. CONCLUSION: MS is a rare malignancy. The diagnosis is often delayed due to a lack of clinical suspicion and the absence of blasts in peripheral blood. This report aims to enhance the awareness of pediatric nurse practitioners that MS should also be considered as a differential for an extremity mass.

Azacitidine in combination with shortened venetoclax treatment cycles in patients with acute myeloid leukemia.

The combination of venetoclax with hypomethylating agents is currently the standard of care for elderly patients with acute myeloid leukemia (AML) ineligible for intensive chemotherapy. Despite its favorable efficacy, clinical use is often associated with post-remission cytopenia, frequently necessitating treatment delays and dose modifications. This study aims to evaluate the efficacy and safety of shortened venetoclax treatment durations. A multicenter analysis was conducted involving 20 adult AML patients receiving venetoclax (7 or 14 days with 9 and 11 patients, respectively) combined with 5-azacitidine (5-7 days) between 2021 and 2024. The cohort included patients from four German academic centers all treated in first line. Outcome measures included bone marrow response, transfusion dependence, overall survival (OS) and progression-free survival (PFS). Median age was 73.5 years, with 70% of patients having secondary AML. Adverse molecular risk was observed in 75% of patients. The overall response rate (ORR) was 100%, with a composite complete remission rate of 78%. No significant differences in response rates were observed between the 7-day and 14-day venetoclax regimens. Median OS for the cohort was 15 months. Infection-related complications were observed in 55% of patients, with severe sepsis in 20% of cases. In this cohort, shortened venetoclax regimens demonstrated efficacy comparable to standard treatment protocols, with a potential reduction in hematologic toxicity. These findings support the individualization of treatment regimens to optimize clinical outcomes while potentially minimizing adverse effects.

JMJD1C forms condensates to facilitate a RUNX1-dependent gene expression program shared by multiple types of AML cells.

JMJD1C, a member of the lysine demethylase 3 (KDM3) family, is universally required for the survival of several types of acute myeloid leukemia (AML) cells with different genetic mutations, representing a therapeutic opportunity with broad application. Yet how JMJD1C regulates the leukemic programs of various AML cells is largely unexplored. Here we show that JMJD1C interacts with the master hematopoietic transcription factor RUNX1, which thereby recruits JMJD1C to the genome to facilitate a RUNX1-driven transcriptional program that supports leukemic cell survival. The underlying mechanism hinges on the long N-terminal disordered region of JMJD1C, which harbors two inseparable abilities: condensate formation and direct interaction with RUNX1. This dual capability of JMJD1C may influence enhancer-promoter contacts crucial for the expression of key leukemic genes regulated by RUNX1. Our findings demonstrate a previously unappreciated role for the non-catalytic function of JMJD1C in transcriptional regulation, underlying a mechanism shared by different types of leukemias.

Plasma Profiling of Acute Myeloid Leukemia With Fever- and Infection-Related Complications During Chemotherapy-Induced Neutropenia.

BACKGROUND: Acute myeloid leukemia (AML) is a heterogenous and complex blood cancer requiring aggressive treatment. Early identification and prediction of the complications following treatment is vital for effective disease management. AIMS: We explored associations between plasma protein levels and fever- and infection-related complications in 26 AML patients during chemotherapy-induced neutropenia. MATERIAL AND METHODS: Longitudinal plasma profiling was conducted using data-dependent mass spectrometry analysis. RESULTS: Mass spectrometry-based plasma profiling data correlated well with laboratory parameters, including C-reactive protein, and revealed a broader inflammation protein network associated with fever- and infection-related complications. DISCUSSION AND CONCLUSION: These data indicate the potential of longitudinal plasma profiling in AML patients for identifying and predicting complications that may aid in improved disease monitoring and treatment.

The Importance of Confirming False Homozygosity in Pretransplant HLA Typing Results of Patients with Hematologic Malignancies.

Loss of heterozygosity (LOH) on chromosome 6p, where the HLA genes are located, can result in incorrect homozygosity findings during HLA genotyping in patients with hematologic malignancies. The degree of HLA compatibility between donor and recipient is crucial in hematopoietic stem cell transplantation. Therefore, we present a case of false homozygosity in HLA genotyping due to LOH on chromosome 6p in a patient diagnosed with acute myeloid leukemia (AML). HLA molecular typing was conducted on both peripheral blood and buccal swab samples. The analysis included sequence-based typing (SBT) and next-generation sequencing-based typing. Additionally, chromosomal microarray analysis (CMA) was performed. A 68-year-old male presented with anemia and thrombocytopenia. Subsequent bone marrow examination confirmed AML. High-resolution HLA genotyping of Peripheral blood during blast crisis revealed homozygosity at the -A, -B, and -C loci. Conventional karyotyping showed a normal karyotype, 46,XY[20]. Retesting of HLA genotyping one week later confirmed the homozygous results. Subsequently, HLA typing was repeated using buccal swab specimens, confirming heterozygosity at all 4 HLA loci. CMA on peripheral blood samples during blast crisis revealed a large terminal region of copy-neutral LOH spanning approximately 43.5 Mb in the chromosome region 6p25.3p21.1. LOH at the HLA gene locus can significantly impact donor selection, potentially leading to the selection of mistakenly identified homozygous donors. Clinicians and laboratory personnel should be aware of these issues to prevent erroneous HLA typing results in patients with hematologic malignancies. It is advisable to confirm the HLA typing of recipients with hematologic malignancies whenever homozygosity is detected at any locus. This can be achieved through careful interpretation of low peaks in SBT, and by using buccal swab samples or peripheral blood collected after achieving remission.

[Pediatric acute myeloid leukemia].

Acute myeloid leukemia (AML) accounts for approximately 25% of pediatric leukemia cases in Japan, with approximately 150 patients being newly diagnosed with AML annually. Pediatric acute myeloid leukemia is classified into three groups: myeloid leukemia associated with Down syndrome (ML-DS), acute promyelocytic leukemia (APL), and de novo AML. Patients with ML-DS have an event-free survival rate over 80%; however, relapsed patients have dismal outcomes, even if they receive hematopoietic cell transplantation. APL is curable with all-trans retinoic acid and arsenic trioxide. In de novo AML, 10% of patients fail to achieve remission, and approximately 30% of patients who successfully achieve remission subsequently experience AML relapse. This review highlights the therapeutic approach for these three diseases with context from past clinical studies in Japan, and shares promising new therapeutic options for relapsed/refractory de novo AML.

ß-Thalassemia Major Complicated by Acute Myeloid Leukemia.

This report describes the rare co-occurrence of acute myeloid leukemia (AML) French-American-British type M2 in a 4.5-year-old boy with previously diagnosed thalassemia major, an inherited hemoglobinopathy, typically presenting with severe, transfusion-dependent anemia. Chronic transfusions, though lifesaving, can lead to iron overload, which may generate free radicals and potentially contribute to malignancy. Our case highlights the importance of close monitoring for secondary malignancies in thalassemia patients. Our patient born to consanguineous parents, presented with persistent fever, abdominal pain, and splenomegaly. Hematological investigations revealed severe cytopenias (low blood cell counts) and many immature blood cells (blasts). Bone marrow examination confirmed AML M2, characterized by an overabundance of myeloid blasts. Despite the initiation of myeloid leukemia-directed aggressive chemotherapy, the patient, unfortunately, succumbed to the disease within a month of diagnosis.

Influences on the Hematopoietic Stem Cell Niche.

Hematopoietic stem cells (HSCs) are supported by the bone marrow microenvironment to maintain normal production of blood cells. The niche may be considered an "ecosystem" that support the function of HSCs and other supportive cells. Alterations in the bone marrow niche are commonly observed in hematologic malignancies. Here, we review recent insights into the location and the molecular and cellular components of the bone marrow niche. Moreover, we discuss how the niche interacts with HSCs to drive the pathogenesis of hematopoietic malignancies. Overall, a better understanding of the influences on the HSC niche may drive therapeutic development targeting defective and aberrant hematopoiesis.