Comparative features and outcomes between paediatric T-cell and B-cell acute lymphoblastic leukaemia

RSK4 promotes the metastasis of clear cell renal cell carcinoma by activating RUNX1-mediated angiogenesis

Ribosomal S6 protein kinase 4 (RSK4), a member of the serine‒threonine kinase family, plays a vital role in the Ras‒MAPK pathway. This kinase is responsible for managing several cellular activities, including cell growth, proliferation, survival, and mobility. In this study, we observed higher RSK4 protein expression in clear cell renal cell carcinoma (ccRCC) than in normal kidney tissue, and the overexpression of RSK4 might predict poor outcomes for ccRCC patients. Notably, renal cell carcinoma (RCC) is rich in blood vessels; therefore, this study aimed to explore the biological function of RSK4 in ccRCC progression and its specific regulatory mechanism. We analyzed changes in the expression of target genes through transcriptomic and proteomic assessments. We also conducted tube formation assays and VEGF ELISAs to understand the role of RSK4 in angiogenesis. Additionally, we evaluated the regulatory effect of RUNX1 on EPHA2 transcription using a luciferase reporter gene assay and observed that the effect of RUNX1 on activating EPHA2 transcription was negated after the binding site was mutated. Our findings suggested that RSK4 enhanced tube formation by stimulating VEGF secretion. Concurrently, in vivo experiments confirmed that RSK4 expedited RCC metastasis and angiogenesis. This evidence indicates that RSK4 may serve as a new prognostic marker and play a vital role in RCC metastasis.

EBF1-induced CSRP2 boosts the progression of B-cell acute lymphocytic leukemia by inhibiting ferroptosis

B-cell acute lymphocytic leukemia (B-ALL) is a highly aggressive malignancy with poor prognosis. Developing diagnostic markers and therapeutic targets to identify and treat B-ALL early would improve the outcomes of B-ALL patients. Here, we conducted RNA next-generation sequencing using bone marrow (BM) specimens obtained from 7 B-ALL patients and 7 healthy donors. We found cysteine and glycine-rich protein 2 (CSRP2) upregulated in B-ALL. Down-regulation of CSRP2 resulted in suppressed cell proliferation and enhanced cell apoptosis in B-ALL. In addition, inhibition of CSRP2 increased cell ferroptosis in B-ALL cells. Mechanically, we revealed that transcription factor early B cell factor 1 (EBF1) regulated CSRP2 levels in B-ALL, and inhibition of EBF1 decreased CSRP2 levels in B-ALL. In conclusion, the dysregulation EBF1 led to CSRP2 upregulation and resulting in progression of B-ALL. The EBF1/CSRP2 axis could be of great potential as therapeutic targets for B-ALL treatment.

Nelarabine in T-cell acute lymphoblastic leukemia: intracellular metabolism and molecular mode-of-action

T-cell acute lymphoblastic leukemia (T-ALL) patients often have a poor 5-year event-free survival. The only T-ALL specific drug in clinical practice is nelarabine. A prodrug of the deoxyguanosine analog ara-G, nelarabine is a rationally designed agent selective for the treatment of T-cell malignancies. Originally approved for relapsed/refractory T-ALL, it is increasingly used in T-ALL therapy and is currently being evaluated in upfront treatment. Whilst the clinical use of nelarabine has been the topic of multiple review articles, a thorough overview of the preclinical data detailing the molecular underpinnings of its anti-leukemic activity is lacking, which is critical to inform mechanism-based use. Thus, in the present article we conducted a semi-systematic review of the literature and critically evaluated the preclinical knowledge on the molecular pharmacology of nelarabine. Whilst early studies identified ara-G triphosphate to be the principal active metabolite and nuclear DNA synthesis to be a key target, many fundamental questions remain that could inform upon future use of this therapy. These include the nature of nelarabine-induced DNA lesions and their repair, together with additional cellular targets of ara-G metabolites and their role in efficacy and toxicity. A critical avenue of research in need of development is investigation of nelarabine combination therapies, both in the context of current T-ALL chemotherapy regimens and with emerging anti-leukemic agents, and we highlight some areas to pursue. Altogether, we discuss what we can learn from the preclinical literature as a whole and present our view for future research regarding nelarabine treatment in T-ALL.

Treatment of T-cell Leukemia/Lymphoma in Children and Young Adults With the Memorial Sloan Kettering Cancer Center New York IIB Protocol

We described the Memorial Sloan Kettering Cancer Center New York IIB (MSK-NYII) protocol pilot in 1993, for the treatment of acute lymphoblastic leukemia (ALL) in children at high risk of early relapse. We now report MSK-NYII for the treatment of T-ALL/T-lymphoma over a 15-year period. A review of all patient charts identified 63 treated from 1/1/2000-12/31/2015, with a median follow-up of 9.9 years. Further follow-ups were confounded by the COVID pandemic. Remissions (CR) were defined as <5% marrow blast count on Day 28 and resolution of extramedullary disease. Forty-four had T-ALL, and 19 had stage III/IV lymphoblastic lymphoma (T-LL). Median age at diagnosis was 13.6 years (range 0.4 to 23.7). At diagnosis central nervous system (CNS) leukemia was present in 7/63 patients (11%), cranial nerve palsy in 3 (5%), CNS2 [<5cells/µL cerebrospinal fluid with blasts seen on cytospin] in 11 (17%), testicular enlargement in 3 (5%), and mediastinal mass in 45 (71%). On Day 8, 37 T-ALL (86%) were rapid early responders with <25% marrow blasts. 54 patients had an examination, cerebrospinal fluid, and marrow evaluation on day 28. Remission was demonstrated in 53 (98%) after prior marrow and CNS disease. The 19 T-lymphoma patients had no evidence of disease on day 28. Four relapses in marrow were recorded during therapy. Second remissions were able to be achieved. One patient died without having relapsed and is counted as an event in the event-free survival (EFS) analysis. Four patients, including 3 after the second CR transplant, died during follow-up. One unusual case of T-ALL recurred as T-LL of the colon 5.5 years after diagnosis, 3.5 years after therapy discontinuation. Fifteen years after diagnosis 88% (95% CI=78%-98%) survived event-free, and 91% (95% CI=82%-100%) survived. Twenty-five patients received irradiation. Three had RT to the testes, 3 had cranial RT for cranial nerve palsies, and 19 had cranial radiation for either CNS leukemia, CNS2, or for initial white blood cell >100,000/ µL. The MSK-NYIIB protocol, with a 94% 5-year and 88% 15-year EFS, is an effective therapy for the treatment of T-ALL/lymphoma, with similar toxicity to other high-risk regimens.

MOLECULAR PROFILING REVEALS NOVEL GENE FUSIONS AND GENETIC MARKERS FOR REFINED PATIENT STRATIFICATION IN PEDIATRIC ACUTE LYMPHOBLASTIC LEUKEMIA

Risk-adapted treatment protocols conferred remarkable improvement in the survival rates of pediatric acute lymphoblastic leukemia/lymphoma (ALL/LBL). Nevertheless, clinical management is still challenging in certain molecular subgroups and in the presence of alterations associated with an increased rate of relapse. In this study, disease-relevant genomic and transcriptomic profiles were established in a prospective, multicenter, real-world cohort involving 192 children diagnosed with ALL/LBL. Gene fusions were detected in 34.9% of B-ALL and 46.4% of T-ALL patients, with novel chimeric genes involving JAK2, KMT2A, PAX5, RUNX1 and NOTCH1, and with KMT2A-rearranged patients displaying the worst 3-year event-free survival (p=0.019). Non-synonymous mutations were uncovered in 74.9% of the analyzed patients, and a pairwise scrutiny of genetic lesions revealed recurrent clonal selection mechanisms commonly converging on the same pathway (e.g. Ras, JAK/STAT and Notch) in individual patients. Investigation of matched diagnostic and relapse samples unraveled complex subclonal variegation, and mutations affecting the NT5C2, TP53, CDKN2A, and PIK3R1 genes, emerging at the time of relapse. TP53 and CREBBP mutations, even as subclonal aberrations, were associated with shorter 3-year event-free survival among all patients with B-ALL (TP53 mutant vs wild-type: p=0.008, CREBBP mutant vs wild-type: p=0.010); and notably, B-ALL patients showing no measurable residual disease on day 33 could be further stratified based on TP53 mutational status (p<0.001). Our in-depth molecular characterization performed across all risk groups identified novel opportunities for molecularly targeted therapy in 55.9% of high-risk and in 31.6% of standard/intermediate-risk patients.

Repurposing the Whole Expression Transcriptome Assay for the Genetic Diagnosis of T-Cell Acute Lymphoblastic Leukemia and Lymphoma

Unlike other cases of acute leukemia, the diagnosis of T-cell acute lymphoblastic leukemia/lymphoma (T-ALL/LBL) is uniquely based on morphology and flow cytometry. Although the genomic background has been broadly uncovered, the large spectrum of genes involved and the variability of the molecular mechanisms underlying gene deregulation have delayed the introduction of molecular cytogenetics into diagnostic flowcharts. To overcome these limitations and implement a genetic diagnosis of T-ALL/LBLs, we repurposed a whole transcriptome expression assay (WTEa) as a "priority test" to classify T-ALL/LBLs into the major genetic subtypes. We set up and applied a WTEa classifier based on a set of 312 probes on 215 T-ALL/LBLs, which properly assigned >95% of cases with subtype-defining alterations to the corresponding subgroups (ie, TAL/LMO, HOXA, TLX1, TLX3, BCL11B). Among them, it pinpointed cases that harbored cryptic alterations, such as noncoding mutations that generate a new enhancer at TAL1 and LMO2 loci (8% of TAL/LMO), and duplications of noncoding element downstream BCL11B (BETA) (18% of BCL11B). It was also suitable to classify lymphoma cases for which only formalin-fixed embedded tissues were available, as confirmed in cases harboring TLX1 or TLX3 rearrangements, and distinguished new putative subtypes. WTEa offers a unifying tool to provide a genetic classification of T-ALL/LBLs. If introduced in multicenter prospective studies, it will facilitate evaluation of the clinical impact of genetic classification.

Venetoclax and azacitidine in combination with homoharringtonine, cytarabine, and aclarubicin for salvage therapy of relapsed/refractory T cell acute lymphoblastic leukemia

BACKGROUND

The treatment of relapsed/refractory T cell acute lymphoblastic leukemia (R/R T-ALL) is a significant challenge in hematologic oncology, and no standard salvage treatment plan exists. Both Chinese and international clinical guidelines recommend combination chemotherapy including venetoclax.

METHODS

Efficacy and safety of venetoclax, azacitidine, homoharringtonine, cytarabine, and aclarubicin (VA-HAA) combination therapy were retrospectively analyzed in 3 patients with R/R T-ALL at the Department of Hematology, 920th Hospital of the Joint Logistics Support Force, Chinese People's Liberation Army.

RESULTS

The chemotherapy resulted in CR/CRi with negative flow MRD in all 3 patients. Quantitative negative conversion was achieved in 2 patients with fusion genes, and the frequency of monoclonal TCR gene rearrangements was significantly reduced in 1 patient. All patients received stem cell rescue after the chemotherapy. Hematologic toxicity may be manageable, with a median of 24 days for complete recovery of neutrophils (ANC) and 36 days for partial recovery of platelets. There were no major bleeding events or chemotherapy-related deaths.

CONCLUSION

VA-HAA may be an effective and safe salvage treatment for R/R T-ALL, and prospective clinical trials are needed to verify its specific clinical efficacy.

Imaging Flow Cytometric Identification of Chromosomal Defects in Paediatric Acute Lymphoblastic Leukaemia

Acute lymphoblastic leukaemia is the most common childhood malignancy that remains a leading cause of death in childhood. It may be characterised by multiple known recurrent genetic aberrations that inform prognosis, the most common being hyperdiploidy and t(12;21) ETV6::RUNX1. We aimed to assess the applicability of a new imaging flow cytometry methodology that incorporates cell morphology, immunophenotype, and fluorescence in situ hybridisation (FISH) to identify aneuploidy of chromosomes 4 and 21 and the translocation ETV6::RUNX1. We evaluated this new "immuno-flowFISH" platform on 39 cases of paediatric ALL of B-lineage known to have aneuploidy of chromosomes 4 and 21 and the translocation ETV6::RUNX1. After identifying the leukaemic population based on immunophenotype (i.e., expression of CD34, CD10, and CD19 antigens), we assessed for copy numbers of loci for the centromeres of chromosomes 4 and 21 and the ETV6 and RUNX1 regions using fluorophore-labelled DNA probes in more than 1000 cells per sample. Trisomy 4 and 21, tetrasomy 21, and translocations of ETV6::RUNX1, as well as gains and losses of ETV6 and RUNX1, could all be identified based on FISH spot counts and digital imagery. There was variability in clonal makeup in individual cases, suggesting the presence of sub-clones. Copy number alterations and translocations could be detected even when the cell population comprised less than 1% of cells and included cells with a mature B-cell phenotype, i.e., CD19-positive, lacking CD34 and CD10. In this proof-of-principle study of 39 cases, this sensitive and specific semi-automated high-throughput imaging flow cytometric immuno-flowFISH method has been able to show that alterations in ploidy and ETV6::RUNX1 could be detected in the 39 cases of paediatric ALL. This imaging flow cytometric FISH method has potential applications for diagnosis and monitoring disease and marrow regeneration (i.e., distinguishing residual ALL from regenerating haematogones) following chemotherapy.

How I treat ETP-ALL in children

ABSTRACT

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is a unique subtype of immature T-cell ALL that was initially associated with a dramatically inferior prognosis compared with non-ETP T-cell ALL (Not-ETP) when it was first described in 2009. Analyses of larger patient cohorts treated with more contemporary regimens, however, have shown minimal survival differences between ETP and Not-ETP. In this manuscript, we use representative cases to explore therapeutic advances and address common clinical questions regarding the management of children, adolescents, and young adults with ETP-ALL. We describe our recommended treatment approach for a child or adolescent with newly diagnosed ETP-ALL, with an emphasis on the prognostic significance of induction failure and detectable minimal residual disease and the role of hematopoietic stem cell transplant in first remission. We discuss the interplay between the ETP immunophenotype and genomic markers of immaturity in T-cell ALL. Finally, we review novel therapeutic approaches that should be considered when managing relapsed or refractory ETP-ALL.

Clinical outcomes and safety of CAR-T cells in treatment of T-Cell acute lymphoblastic leukemia/lymphoma

Relapsed or refractory T-cell acute lymphoblastic leukemia/lymphoma (r/r T-ALL/LBL) are frequently aggressive and associated with unfavorable prognoses. Pan-targeted Chimeric Antigen Receptor (CAR) T-cell therapy have shown promising results in clinical trials. In recent years, CD7 CAR T-cell and CD5 CAR T-cell demonstrate effectiveness in treating r/r T-ALL/LBL patients with bone marrow infiltration. However, nearly half of r/r T-ALL/T-LBL patients are accompanied by extramedullary disease (EMD), where comprehensive data on the efficacy and safety of CAR T-cell therapy remain limited. Additionally, CD7 CAR T-cell and CD5 CAR T-cell therapy can cause severe immunodeficiency and hematologic toxicity, complicating with difficult immune reconstitution. This review provides an in-depth analysis of the safety profile and adverse events associated with CAR T-cell therapy in r/r T-ALL/LBL, with a a particular emphasis on its impact in patients with EMD.

An inflammatory state defines a high-risk T-lineage acute lymphoblastic leukemia subgroup

T-lineage acute lymphoblastic leukemia (ALL) is an aggressive cancer comprising diverse subtypes that are challenging to stratify using conventional immunophenotyping. To gain insights into subset-specific therapeutic vulnerabilities, we performed an integrative multiomics analysis of bone marrow samples from newly diagnosed T cell ALL, early T cell precursor ALL, and T/myeloid mixed phenotype acute leukemia. Leveraging cellular indexing of transcriptomes and epitopes in conjunction with T cell receptor sequencing, we identified a subset of patient samples characterized by activation of inflammatory and stem gene programs. These inflammatory T-lineage samples exhibited distinct biological features compared with other T-lineage ALL samples, including the production of proinflammatory cytokines, prevalence of mutations affecting cytokine signaling and chromatin remodeling, an altered immune microenvironment, and poor treatment responses. Moreover, we found that, although inflammatory T-lineage ALL samples were less sensitive to dexamethasone, they exhibited unique sensitivity to a BCL-2 inhibitor, venetoclax. To facilitate classification of patients with T-lineage ALL, we developed a computational inflammatory gene signature scoring system, which stratified patients and was associated with disease prognosis in three additional patient cohorts. By identifying a high-risk T-lineage ALL subtype on the basis of an inflammatory score, our study provides a framework for targeted therapeutic approaches for these challenging-to-treat cancers.

Clinical Efficacy and Safety of CD7-Targeted CAR T Cell Therapy for T-cell Malignancies: A Systematic Review and Meta-analysis

OBJECTIVES

Although T-cell malignancies are relatively less prevalent compared to B-cell malignancies, they are highly malignant, and patients usually have poor prognoses. Employing CD7-targeted chimeric antigen receptor (CAR) T cell therapy as a novel immunotherapy to treat malignant T cells faces numerous challenges and is in its early phase. To evaluate this possibility, we aimed to review and meta-analyze the related clinical trials systematically.

METHODS

On October 9, 2023, the online databases of PubMed, Scopus, Embase, and Web of Science were systematically searched for pertinent studies. After completing a two-step title/abstract and full-text screening process, the eligible studies were included.

RESULTS

We observed a pooled overall response rate (ORR) of 100%. Partial response (PR), stringent and/or complete response (sCR/CR), and relapse rate were 6%, 85%, and 18%, respectively. Additionally, the pooled rate of minimal residual disease (MRD) negativity was 85%. The most common grade ≥3 adverse events were related to hematological toxicities, including neutropenia (100%), thrombocytopenia (79%), and anemia (57%). Cytokine release syndrome (CRS) was also a frequent complication with a 100% rate; however, 81% of CRS events were low grades. No grade ≥3 GVHD was reported, and the immune effector cell-associated neurotoxicity syndrome (ICANS grade ≥3) was rare (4%).

CONCLUSION

CD7 is an active and safe target that shows promising results in the treatment of relapsed and/or refractory (r/r) T-cell malignancies.

A multiomic atlas identifies a treatment-resistant, bone marrow progenitor-like cell population in T cell acute lymphoblastic leukemia

Refractoriness to initial chemotherapy and relapse after remission are the main obstacles to curing T cell acute lymphoblastic leukemia (T-ALL). While tumor heterogeneity has been implicated in treatment failure, the cellular and genetic factors contributing to resistance and relapse remain unknown. Here we linked tumor subpopulations with clinical outcome, created an atlas of healthy pediatric hematopoiesis and applied single-cell multiomic analysis to a diverse cohort of 40 T-ALL cases. We identified a bone marrow progenitor (BMP)-like leukemia subpopulation associated with treatment failure and poor overall survival. The single-cell-derived molecular signature of BMP-like blasts predicted poor outcome across multiple subtypes of T-ALL and revealed that NOTCH1 mutations additively drive T-ALL blasts away from the BMP-like state. Through in silico and in vitro drug screenings, we identified a therapeutic vulnerability of BMP-like blasts to apoptosis-inducing agents including venetoclax. Collectively, our study establishes multiomic signatures for rapid risk stratification and targeted treatment of high-risk T-ALL.

Allogeneic CD5-specific CAR-T therapy for relapsed/refractory T-ALL: a phase 1 trial

Refractory or relapsed T cell acute lymphoblastic leukemia (r/r T-ALL) patients have poor prognoses, due to the lack of effective salvage therapies. Recently, CD7-targeting chimeric antigen receptor (CAR)-T therapies show efficacy in patients with r/r T-ALL, but relapse with CD7 loss is common. This study evaluates a CD5-gene-edited CAR-T cell therapy targeting CD5 in 19 r/r T-ALL patients, most of whom had previously failed CD7 CAR-T interventions. CAR-T products were derived from previous transplant donors (Cohort A) or newly matched donors (Cohort B). Primary endpoints were dose-limiting toxicity at 21 days and adverse events within 30 days. Secondary endpoints were responses, pharmacokinetics and severe adverse events after 30 days. A total of 16 received infusions, 10 at target dose of 1 × 106 kg-1. All encountered grade 3-4 cytopenias and one had a grade 3 infection within 30 days. All patients (100%) achieved complete remission or complete remission with incomplete blood count recovery by day 30. At a median follow-up of 14.3 months, four received transplantation; three were in remission and one died of infection. Of 12 untransplanted patients, 2 were in remission, 3 relapsed, 5 died of infection and 2 of thrombotic microangiopathy. CAR-T cells persisted and cleared CD5+ T cells. CD5- T cells, mostly CD5-gene-edited, increased but remained below normal levels. These results suggest this CD5-specific CAR-T intervention has a high remission rate for T-ALL patients. Evidence also suggests the risk of late-onset severe infection may be mitigated with consolidative transplantation. This study provides insights that could help to optimize this promising intervention. ClinicalTrials.gov registration: NCT05032599 .

Antitumor activity of niclosamide-mediated oxidative stress against acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is a heterogeneous clonal disease originated from B- or T-cell lymphoid precursor cells. ALL is often refractory or relapses after treatment. Novel treatments are anxiously needed in order to achieve a better response and prolonged overall survival in ALL patients. In the present study, we aimed at examining the antitumor effect of niclosamide on ALL. We investigated the effects of niclosamide on the proliferation and apoptosis in vitro, the growth of ALL cells in xenografted NOD-Prkdcem26Cd52 il2rgem26Cd22 /Nju (NCG) mice. The results showed that niclosamide treatment potently inhibited the growth of ALL cells and induced apoptosis via elevating the levels of reactive oxygen species and activating TP53. These findings suggest that niclosamide may be a promisingly potential agent for ALL therapy.

Epigenetic-modifying agents: The potential game changers in the treatment of hematologic malignancies

Hematologic malignancies are lethal diseases arising from accumulated leukemic cells with substantial genetic or epigenetic defects in their natural development. Epigenetic modifications, including DNA methylation and histone modifications, are critical in hematologic malignancy formation, propagation, and treatment response. Both mutations and aberrant recruitment of epigenetic modifiers are reported in different hematologic malignancies, which regarding the reversible nature of epigenetic regulations, make them a potential target for cancer treatment. Here, we have first outlined a comprehensive overview of current knowledge related to epigenetic regulation's impact on the development and prognosis of hematologic malignancies. Furthermore, we have presented an updated overview regarding the current status of epigenetic-based drugs in hematologic malignancies treatment. And finally, discuss current challenges and ongoing clinical trials based on the manipulation of epigenetic modifies in hematologic malignancies.

CD7-targeting pro-apoptotic extracellular vesicles: A novel approach for T-cell haematological malignancy therapy

T-cell haematological malignancies progress rapidly and have a high mortality rate and effective treatments are still lacking. Here, we developed a drug delivery system utilizing 293T cell-derived extracellular vesicles (EVs) modified with an anti-CD7 single-chain variable fragment (αCD7/EVs). Given the challenges of chemotherapy resistance in patients with T-cell malignancy, we selected cytochrome C (CytC) and Bcl2 siRNA (siBcl2) as therapeutic agents and loaded them into αCD7/EVs (αCD7/EVs/CytC/siBcl2). We found that αCD7/EVs efficiently targeted and were internalized by human T-ALL Molt-4 cells. In addition, the interaction between αCD7 and CD7 switched the EV entry pathway in Molt-4 cells from macropinocytosis-dependent endocytosis to clathrin-mediated endocytosis, thereby reducing EV-lysosome colocalization, ultimately improving CytC delivery efficiency and increasing the cytotoxicity of nascent EVs from EV-treated Molt-4 cells. Notably, αCD7/EVs/CytC/siBcl2 demonstrated similar efficacy against both Molt-4 and chemotherapy-resistant Molt-4 cells (CR-Molt-4). Furthermore, αCD7/EVs/CytC/siBcl2 exhibited high safety, low immunogenicity and minimal impact on human T cells. Therefore, αCD7/EVs/CytC/siBcl2 are promising therapeutic approaches for treating CD7+ T-cell malignancies.

Models for the marrow: A comprehensive review of AI-based cell classification methods and malignancy detection in bone marrow aspirate smears

Given the high prevalence of artificial intelligence (AI) research in medicine, the development of deep learning (DL) algorithms based on image recognition, such as the analysis of bone marrow aspirate (BMA) smears, is rapidly increasing in the field of hematology and oncology. The models are trained to identify the optimal regions of the BMA smear for differential cell count and subsequently detect and classify a number of cell types, which can ultimately be utilized for diagnostic purposes. Moreover, AI is capable of identifying genetic mutations phenotypically. This pipeline has the potential to offer an accurate and rapid preliminary analysis of the bone marrow in the clinical routine. However, the intrinsic complexity of hematological diseases presents several challenges for the automatic morphological assessment. To ensure general applicability across multiple medical centers and to deliver high accuracy on prospective clinical data, AI models would require highly heterogeneous training datasets. This review presents a systematic analysis of models for cell classification and detection of hematological malignancies published in the last 5 years (2019-2024). It provides insight into the challenges and opportunities of these DL-assisted tasks.

Fratricide-resistant CD7-CAR T cells in T-ALL

T cell acute lymphoblastic leukemia (T-ALL) is difficult to treat when it relapses after therapy or is chemoresistant; the prognosis of patients with relapsed or refractory T-ALL is generally poor. We report a case series of 17 such patients who received autologous chimeric antigen receptor (CAR) T cells expressing an anti-CD7 CAR and an anti-CD7 protein expression blocker (PEBL), which prevented CAR T cell fratricide. Despite high leukemic burden and low CAR T cell dosing, 16 of the 17 patients attained minimal residual disease-negative complete remission within 1 month. The remaining patient had CD7- T-ALL cells before infusion, which persisted after infusion. Toxicities were mild: cytokine release syndrome grade 1 in ten patients and grade 2 in three patients; immune effector cell-associated neurotoxicity syndrome grade 1 in two patients. Eleven patients remained relapse-free (median follow-up, 15 months), including all nine patients who received an allotransplant. The first patient is in remission 55 months after infusion without further chemotherapy or transplantation; circulating CAR T cells were detectable for 2 years. T cells regenerating after lymphodepletion lacked CD7 expression, were polyclonal and responded to SARS-CoV-2 vaccination; CD7+ immune cells reemerged concomitantly with CAR T cell disappearance. In conclusion, autologous anti-CD7 PEBL-CAR T cells have powerful antileukemic activity and are potentially an effective option for the treatment of T-ALL.

The third generation AKR1C3-activated prodrug, ACHM-025, eradicates disease in preclinical models of aggressive T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy that expresses high levels of the enzyme aldo-keto reductase family 1 member C3 (AKR1C3). To exploit this finding, we developed a novel prodrug, ACHM-025, which is selectively activated by AKR1C3 to a nitrogen mustard DNA alkylating agent. We show that ACHM-025 has potent in vivo efficacy against T-ALL patient-derived xenografts (PDXs) and eradicated the disease in 7 PDXs. ACHM-025 was significantly more effective than cyclophosphamide both as a single agent and when used in combination with cytarabine/6-mercaptopurine. Notably, ACHM-025 in combination with nelarabine was curative when used to treat a chemoresistant T-ALL PDX in vivo. The in vivo efficacy of ACHM-025 directly correlated with AKR1C3 expression levels, providing a predictive biomarker for response. Together, our work provides strong preclinical evidence highlighting the potential of ACHM-025 as a targeted and effective therapy for aggressive forms of T-ALL.

Results of the prospective EORTC Children Leukemia Group study 58081 in precursor B- and T-cell acute lymphoblastic leukemia

Here, we report the results of the prospective cohort study EORTC-CLG 58081 and compare them to the control arm of the randomized phase 3 trial EORTC-CLG 58951, on which treatment recommendations were built. In both studies, patients aged 1-18 years with BCR::ABL1 negative acute lymphoblastic leukemia of the B-lineage (B-ALL) or T-lineage (T-ALL) were treated using a BFM backbone without cranial irradiation. Similarly to the control arm of 58951, prednisolone (PRED) 60 mg/m2/day was used for induction therapy, but a few modifications were made. Dexamethasone (DXM) was used in average-risk 2 (AR2) T-ALL and B-ALL during induction, 10 and 6 mg/m2/day, respectively. Leucovorin rescue was delayed to 42 h instead of 36 h after initiation of high-dose methotrexate, and a postconsolidation MRD time point was added to stratify patients. Between 2011 and 2017, 835 patients were prospectively enrolled in the 58081 study. Overall, the 5-year event-free survival (EFS) was 84.8% versus 83.6% (hazard ratio [HR], 0.96 [95% confidence interval [CI]: 0.76-1.21]) for 58081 versus 58951 considered as a control group, respectively, 84.3% versus 84.9% (HR, 1.06 [99% CI: 0.75-1.49]) in B-ALL but 87.3% versus 76.6% (HR, 0.59 [99% CI: 0.28-1.24]) in T-ALL. The comparison between the two studies regarding EFS differed by risk group (p = 0.012). The HR was 2.15 (99% CI: 0.67-6.85) for very low-risk but 0.34 (99% CI: 0.13-0.89) for AR2. The particularly favorable results observed in the T-ALLs and AR2 subgroups suggest the benefit of using DXM in specific patient groups and highlight the importance of risk stratification.

Unexpected Mediastinal Mass Etiology in B-Acute Lymphoblastic Leukemia

Leukemic masses are a known complication in patients with hematologic malignancies. Here we present a case regarding a patient with recently diagnosed B-acute lymphoblastic leukemia (B-ALL) who presented with multiple sites of extramedullary involvement including an anterior mediastinal mass. This mass persisted despite multiple rounds of multiagent cytotoxic therapy. In this report, we summarize the literature regarding mediastinal masses in the setting of B-ALL and illustrate that such masses in patients with leukemias may have surprising etiology, separate from the primary disease.

Folylpolyglutamate synthetase inactivation in relapsed ALL induces a druggable folate metabolic vulnerability

AIMS

The antifolate methotrexate (MTX) is an anchor drug used in acute lymphoblastic leukemia (ALL) with poorly understood chemoresistance mechanisms in relapse. Herein we find decreased folate polyglutamylation network activities and inactivating FPGS mutations, both of which could induce MTX resistance and folate metabolic vulnerability in relapsed ALL.

METHODS

We utilized integrated systems biology analysis of transcriptomic and genomic data from relapse ALL cohorts to infer hidden ALL relapse drivers and related genetic alternations during clonal evolution. The drug sensitivity assay was used to determine the impact of relapse-specific FPGS mutations on sensitivity to different antifolates and chemotherapeutics in ALL cells. We used liquid chromatography-mass spectrometry (LC-MS) to quantify MTX and folate polyglutamate levels in folylpoly-γ-glutamate synthetase (FPGS) mutant ALL cells. Enzymatic activity and protein degradation assays were also conducted to characterize the catalytic properties and protein stabilities of FPGS mutants. An ALL cell line-derived mouse leukemia xenograft model was used to evaluate the in vivo impact of FPGS inactivation on leukemogenesis and sensitivity to the polyglutamatable antifolate MTX as well as non-polyglutamatble lipophilic antifolate trimetrexate (TMQ).

RESULTS

We found a significant decrease in folate polyglutamylation network activities during ALL relapse using RNA-seq data. Supported by functional evidence, we identified multifactorial mechanisms of FPGS inactivation in relapsed ALL, including its decreased network activity and gene expression, focal gene deletion, impaired catalytic activity, and increased protein degradation. These deleterious FPGS alterations induce MTX resistance and inevitably cause marked intracellular folate shrinkage, which could be efficiently targeted by a polyglutamylation-independent lipophilic antifolate TMQ in vitro and in vivo.

CONCLUSIONS

MTX resistance in relapsed ALL relies on FPGS inactivation, which inevitably induces a folate metabolic vulnerability, allowing for an efficacious antifolate ALL treatment strategy that is based upon TMQ, thereby surmounting chemoresistance in relapsed ALL.

Unlocking the Complexity: Exploration of Acute Lymphoblastic Leukemia at the Single Cell Level

Acute lymphoblastic leukemia (ALL) is the most common cancer in children. ALL originates from precursor lymphocytes that acquire multiple genomic changes over time, including chromosomal rearrangements and point mutations. While a large variety of genomic defects was identified and characterized in ALL over the past 30 years, it was only in recent years that the clonal heterogeneity was recognized. Thanks to the latest advancements in single-cell sequencing techniques, which have evolved from the analysis of a few hundred cells to the analysis of thousands of cells simultaneously, the study of tumor heterogeneity now becomes possible. Different modalities can be explored at the single-cell level: DNA, RNA, epigenetic modifications, and intracellular and cell surface proteins. In this review, we describe these techniques and highlight their advantages and limitations in the study of ALL biology. Moreover, multiomics technologies and the incorporation of the spatial dimension can provide insight into intercellular communication. We describe how the different single-cell sequencing technologies help to unravel the molecular complexity of ALL, shedding light on its development, its heterogeneity, its interaction with the leukemia microenvironment and possible relapse mechanisms.

Precision Medicine for Acute Lymphoblastic Leukemia in Children: A Review

The clinical outcome for children diagnosed with acute lymphoblastic leukemia is a testimony to the success of modern medicine. Over the past few decades, survival has climbed from ∼10% to >90% for certain subgroups. Yet, the outcome for those with relapsed disease is often poor, and survivors struggle with a multitude of healthcare issues, some of which are lifelong. In recent years, the advent of the widespread sequencing of tumors has made available patients with previously unrecognized subtypes of leukemia, who have the potential to benefit from the addition of targeted therapies. Indeed, the promise of precision medicine, encompassing a person's environment, genetics and lifestyle, is likely to have profound impact on further tailoring therapies that are likely to improve outcomes, diminish toxicity and ultimately pave the pathway for a healthier population.

The pros and cons of probiotic use in pediatric oncology patients following treatment for acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) treatment, involving chemotherapy, radiotherapy, and pharmacotherapy (antibiotics, antineoplastics) perturbs the gut microbiota in pediatric patients, with enduring effects post-treatment. ALL treatments diminish microbial richness and diversity, favoring pathogenic bacteria. Probiotics may offer promise in mitigating these disruptions and associated side effects. This mini-review explores the impact of ALL treatment on the gut microbiota and the potential benefits of probiotics in pediatric oncology. Probiotics have shown promise in restoring gut microbial balance, reducing treatment-associated side effects, and potentially improving quality of life. However, potential adverse effects, particularly in immunocompromised patients, warrant caution. Notably, there's emerging interest in probiotics' role in bone health and mineral bioaccessibility. Further research is needed to elucidate probiotics' mechanisms and their broader impact on pediatric health. Integration of probiotics into ALL treatment and post-treatment regimens offers significant potential for improving patient outcomes and reducing treatment-related complications and long-lasting disruptions, although careful monitoring is essential.

Selective Inhibition of Deamidated Triosephosphate Isomerase by Disulfiram, Curcumin, and Sodium Dichloroacetate: Synergistic Therapeutic Strategies for T-Cell Acute Lymphoblastic Leukemia in Jurkat Cells

T-cell acute lymphoblastic leukemia (T-ALL) is a challenging childhood cancer to treat, with limited therapeutic options and high relapse rates. This study explores deamidated triosephosphate isomerase (dTPI) as a novel therapeutic target. We hypothesized that selectively inhibiting dTPI could reduce T-ALL cell viability without affecting normal T lymphocytes. Computational modeling and recombinant enzyme assays revealed that disulfiram (DS) and curcumin (CU) selectively bind and inhibit dTPI activity without affecting the non-deamidated enzyme. At the cellular level, treatment with DS and CU significantly reduced Jurkat T-ALL cell viability and endogenous TPI enzymatic activity, with no effect on normal T lymphocytes, whereas the combination of sodium dichloroacetate (DCA) with DS or CU showed synergistic effects. Furthermore, we demonstrated that dTPI was present and accumulated only in Jurkat cells, confirming our hypothesis. Finally, flow cytometry confirmed apoptosis in Jurkat cells after treatment with DS and CU or their combination with DCA. These findings strongly suggest that targeting dTPI represents a promising and selective target for T-ALL therapy.

Enhancer looping protein LDB1 modulates MYB expression in T-ALL cell lines in vitro by cooperating with master transcription factors

BACKGROUND

Despite significant progress in the prognosis of pediatric T-cell acute lymphoblastic leukemia (T-ALL) in recent decades, a notable portion of children still confronts challenges such as treatment resistance and recurrence, leading to limited options and a poor prognosis. LIM domain-binding protein 1 (LDB1) has been confirmed to exert a crucial role in various physiological and pathological processes. In our research, we aim to elucidate the underlying function and mechanisms of LDB1 within the background of T-ALL.

METHODS

Employing short hairpin RNA (shRNA) techniques, we delineated the functional impact of LDB1 in T-ALL cell lines. Through the application of RNA-Seq, CUT&Tag, and immunoprecipitation assays, we scrutinized master transcription factors cooperating with LDB1 and identified downstream targets under LDB1 regulation.

RESULTS

LDB1 emerges as a critical transcription factor co-activator in cell lines derived from T-ALL. It primarily collaborates with master transcription factors (ERG, ETV6, IRF1) to cooperatively regulate the transcription of downstream target genes. Both in vitro and in vivo experiments affirm the essential fuction of LDB1 in the proliferation and survival of cell lines derived from T-ALL, with MYB identified as a significant downstream target of LDB1.

CONCLUSIONS

To sum up, our research establishes the pivotal fuction of LDB1 in the tumorigenesis and progression of T-ALL cell lines. Mechanistic insights reveal that LDB1 cooperates with ERG, ETV6, and IRF1 to modulate the expression of downstream effector genes. Furthermore, LDB1 controls MYB through remote enhancer modulation, providing valuable mechanistic insights into its involvement in the progression of T-ALL.

Epigenetic mechanisms and oral mucositis in children with acute lymphoblastic leukaemia

This study aimed to investigate the relationship between epigenetic mechanisms and oral mucositis (OM) in paediatric patients with acute lymphoblastic leukaemia. Oral cells were collected from 76 participants, including 15 healthy individuals, 10 patients with acute lymphoblastic leukaemia but without a history of OM and 51 acute lymphoblastic leukaemia patients with a history of OM (35 with active OM and 16 who had recovered from OM). Global DNA methylation in the miR-9-1 and miR-9-3 genes was performed. Seven polymorphisms rs1801131, rs1801133 (MTHFR), rs2228611 (DNMT1), rs7590760, rs1550117 (DNMT3A), rs6087990, rs2424913 (DNMT3B) were genotyped and an analysis of association with global DNA methylation was performed. The global methylation levels were lower in cancer patients recovered from OM than in the other groups. A higher frequency of unmethylated profile for miR-9-1 and partially methylated profile for miR-9-3 was observed in cancer patients regardless of OM history compared to healthy patients. The GG genotype of the rs2228611 (DNMT1) polymorphism was associated with higher levels of global methylation in cancer patients irrespective of OM. It was concluded that global methylation is associated with mucosal recovery. The effect of DNMT1 genotype on the global DNA methylation profile, as well as the methylation profile of miR-9-1 and miR-9-3 in cancer patients is independent of OM.

T cell receptor-directed antibody-drug conjugates for the treatment of T cell-derived cancers

T cell-derived cancers are hallmarked by heterogeneity, aggressiveness, and poor clinical outcomes. Available targeted therapies are severely limited due to a lack of target antigens that allow discrimination of malignant from healthy T cells. Here, we report a novel approach for the treatment of T cell diseases based on targeting the clonally rearranged T cell receptor displayed by the cancerous T cell population. As a proof of concept, we identified an antibody with unique specificity toward a distinct T cell receptor (TCR) and developed antibody-drug conjugates, precisely recognizing and eliminating target T cells while preserving overall T cell repertoire integrity and cellular immunity. Our anti-TCR antibody-drug conjugates demonstrated effective receptor-mediated cell internalization, associated with induction of cancer cell death with strong signs of apoptosis. Furthermore, cell proliferation-inhibiting bystander effects observed on target-negative cells may contribute to the molecules' anti-tumor properties precluding potential tumor escape mechanisms. To our knowledge, this represents the first anti-TCR antibody-drug conjugate designed as custom-tailored immunotherapy for T cell-driven pathologies.

Prognosis of pediatric BCP-ALL with IKZF1 deletions and impact of intensive chemotherapy: Results of SCCLG-2016 study

BACKGROUND

IKZF1 deletion (IKZF1del) is associated with poor prognosis in B-cell precursor acute lymphoblastic leukemia (BCP-ALL). But the prognosis of IKZF1del combined with other prognostic stratification factors remains unclear. Whether intensified treatment improves BCP-ALL prognosis has not been determined.

METHODS

A retrospective analysis was performed on 1291 pediatric patients diagnosed with BCP-ALL and treated with the South China Children's Leukemia 2016 protocol. Patients were stratified based on IKZF1 status for comparison of characteristics and outcome. Additionally, IKZF1del patients were further divided based on chemotherapy intensity for outcome assessments.

RESULTS

The BCP-ALL pediatric patients with IKZF1del in south China showed poorer early response. Notably, the DFS and OS for IKZF1del patients were markedly lower than IKZF1wt group (3-year DFS: 88.7% [95% CI: 83.4%-94.0%] vs. 93.5% [95% CI: 92.0%-94.9%], P = .021; 3-year OS: 90.7% [95% CI: 85.8% to 95.6%] vs. 96.1% [95% CI: 95% to 97.2%, P = .003]), with a concurrent increase in 3-year TRM (6.4% [95% CI: 2.3%-10.5%] vs. 2.9% [95% CI: 1.9%-3.8%], P = .025). However, the 3-year CIR was comparable between the two groups (5.7% [95% CI: 1.8%-9.5%] vs. 3.7% [95% CI: 2.6%-4.7%], P = .138). Subgroup analyses reveal no factor significantly influenced the prognosis of the IKZF1del cohort. Noteworthy, intensive chemotherapy improved DFS from 85.7% ± 4.1% to 94.1% ± 0.7% in IKZF1del group (P = .084). Particularly in BCR::ABL positive subgroup, the 3-year DFS was remarkably improved from 53.6% ± 20.1% with non-intensive chemotherapy to 100% with intensive chemotherapy (P = .026).

CONCLUSIONS

Pediatric BCP-ALL patients with IKZF1del in South China manifest poor outcomes without independent prognostic significance. While no factor substantially alters the prognosis in the IKZF1del group. Intensified chemotherapy may reduce relapse rates and improve DFS in patients with IKZF1del subset, particularly in IKZFdel patients with BCR::ABL positive.

Clinicopathologic features and outcomes of acute leukemia harboring PICALM::MLLT10 fusion

The PICALM::MLLT10 fusion is a rare but recurrent cytogenetic abnormality in acute leukemia, with limited clinicopathologic and outcome data available. Herein, we analyzed 156 acute leukemia patients with PICALM::MLLT10 fusion, including 12 patients from our institutions and 144 patients from the literature. The PICALM::MLLT10 fusion preferentially manifested in pediatric and young adult patients, with a median age of 24 years. T-lymphoblastic leukemia/lymphoma (T-ALL) constituted 65% of cases, acute myeloid leukemia (AML) 27%, and acute leukemia of ambiguous lineage (ALAL) 8%. About half of T-ALL were classified as an early T-precursor (ETP)-ALL. In our institutions' cohort, mediastinum was the most common extramedullary site of involvement. Eight of 12 patients were diagnosed with T-ALL exhibiting a pro-/pre-T stage phenotype (CD4/CD8-double negative, CD7-positive), and frequent CD79a expression. NGS revealed pathogenic mutations in 5 of 6 tested cases, including NOTCH1, and genes in RAS and JAK-STAT pathways and epigenetic modifiers. Of 138 cases with follow-up, pediatric patients (<18 years) had 5-year overall survival (OS) of 71%, significantly better than adults at 33%. The 5-year OS for AML patients was 25%, notably shorter than T-ALL patients at 54%; this distinction was observed in both pediatric and adult populations. Furthermore, adult but not pediatric ETP-ALL patients demonstrated inferior survival compared to non-ETP-ALL patients. Neither karyotype complexity nor transplant status had a discernible impact on OS. In conclusion, PICALM::MLLT10 fusion is most commonly seen in T-ALL patients, particularly those with an ETP phenotype. AML and adult ETP-ALL patients had adverse prognosis. PICALM::MLTT10 fusion testing should be considered in T-ALL, AML, and ALAL patients.

Prediction of Response to FDA-Approved Targeted Therapy and Immunotherapy in Acute Lymphoblastic Leukemia (ALL)

OPINION STATEMENT

Acute lymphoblastic leukemia (ALL) represents the predominant cancer in pediatric populations, though its occurrence in adults is relatively rare. Pre-treatment risk stratification is crucial for predicting prognosis. Important factors for assessment include patient age, white blood cell (WBC) count at diagnosis, extramedullary involvement, immunophenotype, and cytogenetic aberrations. Minimal residual disease (MRD), primarily assessed by flow cytometry following remission, plays a substantial role in guiding management plans. Over the past decade, significant advancements in ALL outcomes have been witnessed. Conventional chemotherapy has remarkably reduced mortality rates; however, its intensive nature raises safety concerns and has led to the emergence of treatment-resistant cases with recurrence of relapses. Consequently, The U.S. Food and Drug Administration (FDA) has approved several novel treatments for relapsed/refractory ALL due to their demonstrated efficacy, as indicated by improved complete remission and survival rates. These treatments include tyrosine kinase inhibitors (TKIs), the anti-CD19 monoclonal antibody blinatumomab, anti-CD22 inotuzumab ozogamicin, anti-CD20 rituximab, and chimeric antigen receptor (CAR) T-cell therapy. Identifying the variables that influence treatment decisions is a pressing necessity for tailoring therapy based on heterogeneous patient characteristics. Key predictive factors identified in various observational studies and clinical trials include prelymphodepletion disease burden, complex genetic abnormalities, and MRD. Furthermore, the development of serious adverse events following treatment could be anticipated through predictive models, allowing for appropriate prophylactic measures to be considered. The ultimate aim is to incorporate the concept of precision medicine in the field of ALL through valid prediction platform to facilitate the selection of the most suitable treatment approach.

In vivo monitoring of leukemia-niche interactions in a zebrafish xenograft model

Acute lymphoblastic leukemia (ALL) is the most common type of malignancy in children. ALL prognosis after initial diagnosis is generally good; however, patients suffering from relapse have a poor outcome. The tumor microenvironment is recognized as an important contributor to relapse, yet the cell-cell interactions involved are complex and difficult to study in traditional experimental models. In the present study, we established an innovative larval zebrafish xenotransplantation model, that allows the analysis of leukemic cells (LCs) within an orthotopic niche using time-lapse microscopic and flow cytometric approaches. LCs homed, engrafted and proliferated within the hematopoietic niche at the time of transplant, the caudal hematopoietic tissue (CHT). A specific dissemination pattern of LCs within the CHT was recorded, as they extravasated over time and formed clusters close to the dorsal aorta. Interactions of LCs with macrophages and endothelial cells could be quantitatively characterized. This zebrafish model will allow the quantitative analysis of LCs in a functional and complex microenvironment, to study mechanisms of niche mediated leukemogenesis, leukemia maintenance and relapse development.

Waning of Humoral Immunity to Vaccine-Preventable Diseases in Children Treated for Acute Lymphoblastic Leukemia: A Single-Center Retrospective Cross-Sectional Analysis

Objective

The survival rates of children with acute lymphoblastic leukemia (ALL) have improved over the years, but infections remain a significant cause of morbidity and mortality. Chemotherapy has a range of harmful side effects including the loss of protective antibodies against vaccine-preventable diseases. The objective of this study was to evaluate the serological status of pediatric ALL cases before and after intensive chemotherapy.

Materials and Methods

Children treated and followed for ALL at Dokuz Eylül University were included in this retrospective cross-sectional study. Antibody levels against hepatitis A, hepatitis B, and rubella were routinely assessed at both the time of diagnosis and 6 months after completion of chemotherapy. Measles, mumps, and varicella antibody levels were evaluated at only 6 months after treatment.

Results

Seventy-eight children who completed chemotherapy for ALL were enrolled in the study. All participants had non-protective antibody levels for at least one of the diseases. The highest seropositivity rate was found for hepatitis A (55.1%) and the lowest for measles (17.9%) after chemotherapy. Overall, 50.7%, 30.6%, and 45.7% of the patients significantly lost their humoral immunity against hepatitis B, hepatitis A, and rubella, respectively. Patients in the higher-risk group for ALL had lower seropositivity rates than patients of the other risk groups. There were statistically significant relationships between the protective antibody rates for hepatitis A and varicella and the ages of the patients. Except for hepatitis A vaccination, pre-chemotherapy vaccination did not affect post-chemotherapy serology. On the other hand, all children with a history of varicella before diagnosis showed immunity after chemotherapy.

Conclusion

Patients with ALL, including those previously fully vaccinated, are at great risk of infection due to the decrease in protective antibody levels after chemotherapy. There is a need for routine post-chemotherapy serological testing and re-vaccination based on the results obtained.

KMT2A Rearrangements in Leukemias: Molecular Aspects and Therapeutic Perspectives

KMT2A (alias: mixed-lineage leukemia [MLL]) gene mapping on chromosome 11q23 encodes the lysine-specific histone N-methyltransferase 2A and promotes transcription by inducing an open chromatin conformation. Numerous genomic breakpoints within the KMT2A gene have been reported in young children and adults with hematologic disorders and are present in up to 10% of acute leukemias. These rearrangements describe distinct features and worse prognosis depending on the fusion partner, characterized by chemotherapy resistance and high rates of relapse, with a progression-free survival of 30-40% and overall survival below 25%. Less intensive regimens are used in pediatric patients, while new combination therapies and targeted immunotherapeutic agents are being explored in adults. Beneficial therapeutic effects, and even cure, can be reached with hematopoietic stem cell transplantation, mainly in young children with dismal molecular lesions; however, delayed related toxicities represent a concern. Herein, we summarize the translocation partner genes and partial tandem duplications of the KMT2A gene, their molecular impact, clinical aspects, and novel targeted therapies.

Impact of Genetic Ancestry on T-cell Acute Lymphoblastic Leukemia Outcomes

The influence of genetic ancestry on biology, survival outcomes, and risk stratification in T-cell Acute Lymphoblastic Leukemia (T-ALL) has not been explored. Genetic ancestry was genomically-derived from DNA-based single nucleotide polymorphisms in children and young adults with T-ALL treated on Children's Oncology Group trial AALL0434. We determined associations of genetic ancestry, leukemia genomics and survival outcomes; co-primary outcomes were genomic subtype, pathway alteration, overall survival (OS), and event-free survival (EFS). Among 1309 patients, T-ALL molecular subtypes varied significantly by genetic ancestry, including increased frequency of genomically defined ETP-like, MLLT10, and BCL11B-activated subtypes in patients of African ancestry. In multivariable Cox models adjusting for high-risk subtype and pathways, patients of Admixed American ancestry had superior 5-year EFS/OS compared with European; EFS/OS for patients of African and European ancestry were similar. The prognostic value of five commonly altered T-ALL genes varied by ancestry - including NOTCH1 , which was associated with superior OS for patients of European and Admixed American ancestry but non-prognostic among patients of African ancestry. Furthermore, a published five-gene risk classifier accurately risk stratified patients of European ancestry, but misclassified patients of African ancestry. We developed a penalized Cox model which successfully risk stratified patients across ancestries. Overall, 80% of patients had a genomic alteration in at least one gene with differential prognostic impact by genetic ancestry. T-ALL genomics and prognostic associations of genomic alterations vary by genetic ancestry. These data demonstrate the importance of incorporating genetic ancestry into analyses of tumor biology for risk classification algorithms.

Label-Free and Ultra-Sensitive Detection of Dexamethasone Using a FRET Aptasensor Utilizing Cationic Conjugated Polymers

Dexamethasone (Dex) is a widely used glucocorticoid in medical practice, with applications ranging from allergies and inflammation to cerebral edema and shock. Despite its therapeutic benefits, Dex is classified as a prohibited substance for athletes due to its potential performance-enhancing effects. Consequently, there is a critical need for a convenient and rapid detection platform to enable prompt and accurate testing of this drug. In this study, we propose a label-free Förster Resonance Energy Transfer (FRET) aptasensor platform for Dex detection utilizing conjugated polymers (CPs), cationic conjugated polymers (CCPs), and gene finder probes (GFs). The system operates by exploiting the electrostatic interactions between positively charged CCPs and negatively charged DNA, facilitating sensitive and specific Dex detection. The label-free FRET aptasensor platform demonstrated robust performance in detecting Dex, exhibiting high selectivity and sensitivity. The system effectively distinguished Dex from interfering molecules and achieved stable detection across a range of concentrations in a commonly used sports drink matrix. Overall, the label-free FRET Dex detection system offers a simple, cost-effective, and highly sensitive approach for detecting Dex in diverse sample matrices. Its simplicity and effectiveness make it a promising tool for anti-doping efforts and other applications requiring rapid and accurate Dex detection.

[Risk factors for recurrence of childhood acute lymphoblastic leukemia after treatment with the Chinese Children's Cancer Group ALL-2015 protocol]

OBJECTIVES

To investigate the cumulative incidence of recurrence (CIR) in children with acute lymphoblastic leukemia (ALL) after treatment with the Chinese Children's Cancer Group ALL-2015 (CCCG-ALL-2015) protocol and the risk factors for recurrence.

METHODS

A retrospective analysis was conducted on the clinical data of 852 children who were treated with the CCCG-ALL-2015 protocol from January 2015 to December 2019. CIR was calculated, and the risk factors for the recurrence of B-lineage acute lymphoblastic leukemia (B-ALL) were analyzed.

RESULTS

Among the 852 children with ALL, 146 (17.1%) experienced recurrence, with an 8-year CIR of 19.8%±1.6%. There was no significant difference in 8-year CIR between the B-ALL group and the acute T lymphocyte leukemia group (P>0.05). For the 146 children with recurrence, recurrence was mainly observed in the very early stage (n=62, 42.5%) and the early stage (n=46, 31.5%), and there were 42 children with bone marrow recurrence alone (28.8%) in the very early stage and 27 children with bone marrow recurrence alone (18.5%) in the early stage. The Cox proportional-hazards regression model analysis showed that positive MLLr fusion gene (HR=4.177, 95%CI: 2.086-8.364, P<0.001) and minimal residual disease≥0.01% on day 46 (HR=2.013, 95%CI: 1.163-3.483, P=0.012) were independent risk factors for recurrence in children with B-ALL after treatment with the CCCG-ALL-2015 protocol.

CONCLUSIONS

There is still a relatively high recurrence rate in children with ALL after treatment with the CCCG-ALL-2015 protocol, mainly bone marrow recurrence alone in the very early stage and the early stage, and minimal residual disease≥0.01% on day 46 and positive MLLr fusion gene are closely associated with the recurrence of B-ALL.

Differential impact of asparaginase discontinuation on outcomes of children with T-cell acute lymphoblastic leukemia and T-cell lymphoblastic lymphoma

BACKGROUND

Asparaginase is essential for treating T-cell acute lymphoblastic leukemia (T-ALL). Despite the ongoing debate on whether T-ALL and T-cell lymphoblastic lymphoma (T-LBL) are the same disease entity or two distinct diseases, patients with T-LBL often receive the same or similar treatment protocols as those with T-ALL.

METHODS

The outcomes of patients with or without L-asparaginase discontinuation were retrospectively analyzed among four national protocols: Japan Association of Childhood Leukemia Study (JACLS) ALL-02 and ALL-97 for T-ALL and Japanese Pediatric Leukemia/Lymphoma Study Group ALB-NHL03 and JACLS NHL-98 for T-LBL. The hazard ratio (HR) was calculated with the Cox regression model by considering L-asparaginase discontinuation as a time-dependent variable.

RESULTS

In total, 199 patients with T-ALL, and 133 patients with T-LBL were included. L-asparaginase discontinuation compromised event-free survival (EFS) of T-ALL patients (ALL-02: HR 3.32, 95% confidence interval [CI] 1.40-7.90; ALL-97: HR 3.39, 95%CI 1.19-9.67). Conversely, EFS compromise was not detected among T-LBL patients (ALB-NHL03: HR 1.39, 95%CI 0.41-4.68; NHL-98: HR 0.92, 95%CI 0.11-7.60).

CONCLUSION

The effects of L-asparaginase discontinuation differed between T-ALL and T-LBL. We assume that the differential impact results from (1) the inherent differential response to L-asparaginase between them and/or (2) a less stringent assessment of early treatment response in T-LBL than in T-ALL. Given the poor salvage rate of refractory or relapsed T-ALL and T-LBL, optimization of the frontline therapy is critical, and the current study provides a new suggestion for further treatment modifications. However, larger studies in contemporary intensified treatment protocols are required.

Predicting T-Cell Lymphoma in Children From 18F-FDG PET-CT Imaging With Multiple Machine Learning Models

This study aimed to examine the feasibility of utilizing radiomics models derived from 18F-FDG PET/CT imaging to screen for T-cell lymphoma in children with lymphoma. All patients had undergone 18F-FDG PET/CT scans. Lesions were extracted from PET/CT and randomly divided into training and validation sets. Two different types of models were constructed as follows: features that are extracted from standardized uptake values (SUV)-associated parameters, and CT images were used to build SUV/CT-based model. Features that are derived from PET and CT images were used to build PET/CT-based model. Logistic regression (LR), linear support vector machine, support vector machine with the radial basis function kernel, neural networks, and adaptive boosting were performed as classifiers in each model. In the training sets, 77 patients, and 247 lesions were selected for building the models. In the validation sets, PET/CT-based model demonstrated better performance than that of SUV/CT-based model in the prediction of T-cell lymphoma. LR showed highest accuracy with 0.779 [0.697, 0.860], area under the receiver operating characteristic curve (AUC) with 0.863 [0.762, 0.963], and preferable goodness-of-fit in PET/CT-based model at the patient level. LR also showed best performance with accuracy of 0.838 [0.741, 0.936], AUC of 0.907 [0.839, 0.976], and preferable goodness-of-fit in PET/CT-based model at the lesion level. 18F-FDG PET/CT-based radiomics models with different machine learning classifiers were able to screen T-cell lymphoma in children with high accuracy, AUC, and preferable goodness-of-fit, providing incremental value compared with SUV-associated features.

Association of long non-coding RNAs and ABO blood groups with acute lymphoblastic leukemia in Egyptian children

Acute lymphoblastic leukemia (ALL) is the most prevailing cancer among children. Despite extensive studies, ALL etiology is still an unsolved puzzle. Long non-coding RNAs (lncRNAs) emerged as key mediators in cancer etiology. Several lncRNAs are dysregulated in ALL, leading to oncogenic or tumor-suppressive activities. Additionally, a relation between ABO blood groups and hematological malignancies was proposed. The current study intended to explore the association of lncRNAs, ANRIL and LINC-PINT, and their downstream targets, CDKN2A and heme oxygenase-1 (HMOX1), with the incidence of ALL and treatment response, and to determine the distribution of blood groups across different childhood ALL phenotypes. Blood samples were taken from 66 ALL patients (at diagnosis and at the end of remission induction phase) and 39 healthy children. Whole blood was used for blood group typing. Expression of ANRIL, LINC-PINT and CDKN2A was analyzed in plasma by qRT-PCR. Serum HMOX1 was measured using ELISA. ANRIL and CDKN2A were upregulated, while LINC-PINT and HMOX1 were downregulated in newly diagnosed patients. All of which showed remarkable diagnostic performance, where HMOX1 was superior. HMOX1 was independent predictor of ALL as well. LINC-PINT and HMOX1 were significantly upregulated after treatment. Notably, ANRIL and LINC-PINT were associated with poor outcome. No significant difference in the distribution of ABO blood groups was observed between patients and controls. In conclusion, our results suggested an association of ANRIL and LINC-PINT with childhood ALL predisposition, at least in part, through altering CDKN2A and HMOX1 production. Furthermore, the impact of remission induction treatment was newly revealed.

Chimeric antigen receptor T-cell therapy for T-cell acute lymphoblastic leukemia

Chimeric antigen receptor (CAR) T-cell therapy is a new and effective treatment for patients with hematologic malignancies. Clinical responses to CAR T cells in leukemia, lymphoma, and multiple myeloma have provided strong evidence of the antitumor activity of these cells. In patients with refractory or relapsed B-cell acute lymphoblastic leukemia (ALL), the infusion of autologous anti-CD19 CAR T cells is rapidly gaining standard-of-care status and might eventually be incorporated into frontline treatment. In T-ALL, however, leukemic cells generally lack surface molecules recognized by established CAR, such as CD19 and CD22. Such deficiency is particularly important, as outcome is dismal for patients with T-ALL that is refractory to standard chemotherapy and/or hematopoietic stem cell transplant. Recently, CAR T-cell technologies directed against T-cell malignancies have been developed and are beginning to be tested clinically. The main technical obstacles stem from the fact that malignant and normal T cells share most surface antigens. Therefore, CAR T cells directed against T-ALL targets might be susceptible to self-elimination during manufacturing and/or have suboptimal activity after infusion. Moreover, removing leukemic cells that might be present in the cell source used for CAR T-cell manufacturing might be problematic. Finally, reconstitution of T cells and natural killer cells after CAR T-cell infusion might be impaired. In this article, we discuss potential targets for CAR T-cell therapy of T-ALL with an emphasis on CD7, and review CAR configurations as well as early clinical results.

LINC00958 as new diagnostic and prognostic biomarker of childhood acute lymphoblastic leukaemia of B cells

Background

Paediatric acute B-cell lymphoblastic leukaemia is the most common cancer of the paediatric age. Although the advancement of scientific and technological knowledge has ensured a huge step forward in the management of this disease, there are 15%-20% cases of recurrence leading to serious complications for the patient and sometimes even death. It is therefore necessary to identify new and increasingly personalised biomarkers capable of predicting the degree of risk of B-ALL in order to allow the correct management of paediatric leukaemia patients.

Methods

Starting from our previously published results, we validate the expression level of LINC00958 in a cohort of 33 B-ALL and 9 T-ALL childhood patients, using in-silico public datasets as support. Expression levels of LINC00958 in B-ALL patients stratified by risk (high risk vs. standard/medium risk) and who relapsed 3 years after the first leukaemia diagnosis were also evaluated.

Results

We identified the lncRNA LINC00958 as a biomarker of B-ALL, capable of discriminating B-ALL from T-ALL and healthy subjects. Furthermore, we associated LINC00958 expression levels with the disease risk classification (high risk and standard risk). Finally, we show that LINC00958 can be used as a predictor of relapses in patients who are usually stratified as standard risk and thus not always targeted for marrow transplantation.

Conclusions

Our results open the way to new diagnostic perspectives that can be directly used in clinical practice for a better management of B-ALL paediatric patients.

Enhancing of cerebral Abeta clearance by modulation of ABC transporter expression: a review of experimental approaches

Clearance of amyloid-beta (Aβ) from the brain is impaired in both early-onset and late-onset Alzheimer's disease (AD). Mechanisms for clearing cerebral Aβ include proteolytic degradation, antibody-mediated clearance, blood brain barrier and blood cerebrospinal fluid barrier efflux, glymphatic drainage, and perivascular drainage. ATP-binding cassette (ABC) transporters are membrane efflux pumps driven by ATP hydrolysis. Their functions include maintenance of brain homeostasis by removing toxic peptides and compounds, and transport of bioactive molecules including cholesterol. Some ABC transporters contribute to lowering of cerebral Aβ. Mechanisms suggested for ABC transporter-mediated lowering of brain Aβ, in addition to exporting of Aβ across the blood brain and blood cerebrospinal fluid barriers, include apolipoprotein E lipidation, microglial activation, decreased amyloidogenic processing of amyloid precursor protein, and restricting the entrance of Aβ into the brain. The ABC transporter superfamily in humans includes 49 proteins, eight of which have been suggested to reduce cerebral Aβ levels. This review discusses experimental approaches for increasing the expression of these ABC transporters, clinical applications of these approaches, changes in the expression and/or activity of these transporters in AD and transgenic mouse models of AD, and findings in the few clinical trials which have examined the effects of these approaches in patients with AD or mild cognitive impairment. The possibility that therapeutic upregulation of ABC transporters which promote clearance of cerebral Aβ may slow the clinical progression of AD merits further consideration.

Cytogenomic characterization of pediatric T-cell acute lymphoblastic leukemia reveals TCR rearrangements as predictive factors for exceptional prognosis

BACKGROUND

T-cell acute lymphoblastic leukemia (T-ALL) represents a rare and clinically and genetically heterogeneous disease that constitutes 10-15% of newly diagnosed pediatric ALL cases. Despite improved outcomes of these children, the survival rate after relapse is extremely poor. Moreover, the survivors must also endure the acute and long-term effects of intensive therapy. Although recent studies have identified a number of recurrent genomic aberrations in pediatric T-ALL, none of the changes is known to have prognostic significance. The aim of our study was to analyze the cytogenomic changes and their various combinations in bone marrow cells of children with T-ALL and to correlate our findings with the clinical features of the subjects and their treatment responses.

RESULTS

We performed a retrospective and prospective comprehensive cytogenomic analysis of consecutive cohort of 66 children (46 boys and 20 girls) with T-ALL treated according to BFM-based protocols and centrally investigated cytogenetics and immunophenotypes. Using combinations of cytogenomic methods (conventional cytogenetics, FISH, mFISH/mBAND, arrayCGH/SNP and MLPA), we identified chromosomal aberrations in vast majority of patients (91%). The most frequent findings involved the deletion of CDKN2A/CDKN2B genes (71%), T-cell receptor (TCR) loci translocations (27%), and TLX3 gene rearrangements (23%). All chromosomal changes occurred in various combinations and were rarely found as a single abnormality. Children with aberrations of TCR loci had a significantly better event free (p = 0.0034) and overall survival (p = 0.0074), all these patients are living in the first complete remission. None of the abnormalities was an independent predictor of an increased risk of relapse.

CONCLUSIONS

We identified a subgroup of patients with TCR aberrations (both TRA/TRD and TRB), who had an excellent prognosis in our cohort with 5-year EFS and OS of 100%, regardless of the presence of other abnormality or the translocation partner. Our data suggest that escalation of treatment intensity, which may be considered in subsets of T-ALL is not needed for nonHR (non-high risk) patients with TCR aberrations.

Identifying Candidate Gene Drivers Associated with Relapse in Pediatric T-Cell Acute Lymphoblastic Leukemia Using a Gene Co-Expression Network Approach

Pediatric T-cell Acute Lymphoblastic Leukemia (T-ALL) relapses are still associated with a dismal outcome, justifying the search for new therapeutic targets and relapse biomarkers. Using single-cell RNA sequencing (scRNAseq) data from three paired samples of pediatric T-ALL at diagnosis and relapse, we first conducted a high-dimensional weighted gene co-expression network analysis (hdWGCNA). This analysis highlighted several gene co-expression networks (GCNs) and identified relapse-associated hub genes, which are considered potential driver genes. Shared relapse-expressed genes were found to be related to antigen presentation (HLA, B2M), cytoskeleton remodeling (TUBB, TUBA1B), translation (ribosomal proteins, EIF1, EEF1B2), immune responses (MIF, EMP3), stress responses (UBC, HSP90AB1/AA1), metabolism (FTH1, NME1/2, ARCL4C), and transcriptional remodeling (NF-κB family genes, FOS-JUN, KLF2, or KLF6). We then utilized sparse partial least squares discriminant analysis to select from a pool of 481 unique leukemic hub genes, which are the genes most discriminant between diagnosis and relapse states (comprising 44, 35, and 31 genes, respectively, for each patient). Applying a Cox regression method to these patient-specific genes, along with transcriptomic and clinical data from the TARGET-ALL AALL0434 cohort, we generated three model gene signatures that efficiently identified relapsed patients within the cohort. Overall, our approach identified new potential relapse-associated genes and proposed three model gene signatures associated with lower survival rates for high-score patients.

Pharmacodynamic and Toxicity Studies of 6-Isopropyldithio-2'-guanosine Analogs in Acute T-Lymphoblastic Leukemia

(1) Background: The research group has developed a new small molecule, 6-Isopropyldithio-2'-deoxyguanosine analogs-YLS004, which has been shown to be the most sensitive in acute T-lymphoblastic leukemia cells. Moreover, it was found that the structure of Nelarabine, a drug used to treat acute T-lymphoblastic leukemia, is highly similar to that of YLS004. Consequently, the structure of YLS004 was altered to produce a new small molecule inhibitor for this study, named YLS010. (2) Results: YLS010 has exhibited potent anti-tumor effects by inducing cell apoptosis and ferroptosis. A dose gradient was designed for in vivo experiments based on tentative estimates of the toxicity dose using acute toxicity in mice and long-term toxicity in rats. The study found that YLS010 at a dose of 8 mg/kg prolonged the survival of late-stage acute T-lymphoblastic leukemia mice in the mouse model study. (3) Conclusions: YLS010 has demonstrated specific killing effects against acute T-lymphoblastic leukemia both in vivo and in vitro. Preclinical studies of YLS010 offer a new opportunity for the treatment of patients with acute T-lymphoblastic leukemia in clinical settings.

Quantitative computed tomography analysis of body composition changes in paediatric patients with acute lymphoblastic leukaemia

Children with acute lymphoblastic leukaemia (ALL) are at risk for obesity and cardiometabolic diseases. To gain insight into body composition changes among children with ALL, we assessed quantitative computed tomography (QCT) data for specific body compartments (subcutaneous adipose tissue [SAT], visceral adipose tissue [VAT], total adipose tissue [TAT], lean tissue [LT], LT/TAT and VAT/SAT at lumbar vertebrae L1 and L2) at diagnosis and at off-therapy for 189 children with ALL and evaluated associations between body mass index (BMI) Z-score and clinical characteristics. BMI Z-score correlated positively with SAT, VAT and TAT and negatively with LT/TAT and VAT/SAT. At off-therapy, BMI Z-score, SAT, VAT and TAT values were higher than at diagnosis, but LT, LT/TAT and VAT/SAT were lower. Patients aged ≥10 years at diagnosis had higher SAT, VAT and TAT and lower LT and LT/TAT than patients aged 2.0-9.9 years. Female patients had lower LT and LT/TAT than male patients. Black patients had less VAT than White patients. QCT analysis showed increases in adipose tissue and decreases in LT during ALL therapy when BMI Z-scores increased. Early dietary and physical therapy interventions should be considered, particularly for patients at risk for obesity.