Inherited and Somatic Defects in DDX41 in Myeloid Neoplasms

Combination therapy with venetoclax and azacitidine for the treatment of myelodysplastic syndromes with DDX41 mutations

Myelodysplastic syndromes (MDS) patients with DEAD-box helicase 41 (DDX41) mutations have been reported to be treated effectively with lenalidomide; however, there are no randomized studies to prove it. Venetoclax and azacitidine are safe and effective in high-risk MDS/AML. In this study, we evaluated the efficacy of venetoclax and azacitidine combination therapy in eight consecutive MDS patients with DDX41 mutations at our centre from March 2021 to November 2023. We retrospectively analyzed the genetic features and clinical characteristics of these patients. Our findings suggest that MDS patients with DDX41 mutation may benefit from the therapy, for six subjects received this regimen as initial therapy and five of the six subjects achieved complete remission.

Prevalence and clinical outcomes of germline variants among patients with myeloid neoplasms

AIMS

Myeloid neoplasms (MNs) with germline predisposition have been recognised as a distinct entity. Emerging evidence suggests that sporadic myelodysplastic syndromes may also harbour undetected germline predispositions. We investigated germline alterations in a cohort of 122 adult Thai MNs.

METHODS

MN patients were recruited and tested for germline variants using deep targeted next-generation sequencing. The germline variant was filtered using American College of Medical Genetics classifications and then evaluated for the association with clinical characteristics and outcomes.

RESULTS

Our findings revealed pathogenic/likely pathogenic germline alterations in 12 (10%) of the patients. These germline lesions were commonly found in the DNA damage response pathway (n=6, 50%). We also identified novel deleterious FANCA A1219GfsTer59 variants in two patients diagnosed with secondary acute myeloid leukaemia (sAML) from aplastic anaemia and AML with myelodysplasia related. Among sAML, individuals with germline mutations had inferior overall survival compared with those with wild-type alleles (2 months vs 12 months) with HR 4.7 (95% CI 1.0 to 20), p=0.037. Therefore, the presence of pathogenic or likely pathogenic mutations may be linked to inferior survival outcomes.

CONCLUSIONS

Our study highlighted that the prevalence of germline predisposition in Southeast Asian populations is comparable to that in Caucasians. This underscores the importance of germline genetic testing within the Asian population.

Evaluation of the pathogenic potential of germline DDX41 variants in hematopoietic neoplasms using the ACMG/AMP guidelines

Clinical use of gene panel testing for hematopoietic neoplasms in areas, such as diagnosis, prognosis prediction, and exploration of treatment options, has increased in recent years. The keys to interpreting gene variants detected in gene panel testing are to distinguish between germline and somatic variants and accurately determine whether the detected variants are pathogenic. If a variant is suspected to be a pathogenic germline variant, it is essential to confirm its consistency with the disease phenotype and gather a thorough family history. Donor eligibility must also be considered, especially if the patient's variant is also detected in the expected donor for hematopoietic stem cell transplantation. However, determining the pathogenicity of gene variants is often complicated, given the current limited availability of databases covering germline variants of hematopoietic neoplasms. This means that hematologists will frequently need to interpret gene variants themselves. Here, we outline how to assess the pathogenicity of germline variants according to criteria from the American College of Medical Genetics and Genomics/Association for Molecular Pathology standards and guidelines for the interpretation of variants using DDX41, a gene recently shown to be closely associated with myeloid neoplasms with a germline predisposition, as an example.

A Brief Overview of the Molecular Landscape of Myelodysplastic Neoplasms

Myelodysplastic neoplasm (MDS) is a heterogeneous group of clonal hematological disorders that originate from the hematopoietic and progenitor cells and present with cytopenias and morphologic dysplasia with a propensity to progress to bone marrow failure or acute myeloid leukemia (AML). Genetic evolution plays a critical role in the pathogenesis, progression, and clinical outcomes of MDS. This process involves the acquisition of genetic mutations in stem cells that confer a selective growth advantage, leading to clonal expansion and the eventual development of MDS. With the advent of next-generation sequencing (NGS) assays, an increasing number of molecular aberrations have been discovered in recent years. The knowledge of molecular events in MDS has led to an improved understanding of the disease process, including the evolution of the disease and prognosis, and has paved the way for targeted therapy. The 2022 World Health Organization (WHO) Classification and the International Consensus Classification (ICC) have incorporated the molecular signature into the classification system for MDS. In addition, specific germline mutations are associated with MDS development, especially in pediatrics and young adults. This article reviews the genetic abnormalities of MDS in adults with a brief review of germline predisposition syndromes.

First report of familial mixed phenotype acute leukemia: shared clinical characteristics, Philadelphia translocation, and germline variants

While our understanding of the molecular basis of mixed phenotype acute leukemia (MPAL) has progressed over the decades, our knowledge is limited and the prognosis remains poor. Investigating cases of familial leukemia can provide insights into the role of genetic and environmental factors in leukemogenesis. Although familial cases and associated mutations have been identified in some leukemias, familial occurrence of MPAL has never been reported. Here, we report the first cases of MPAL in a family. A 68-year-old woman was diagnosed with MPAL and received haploidentical stem cell transplantation from her 44-year-old son. In four years, the son himself developed MPAL. Both cases exhibited similar characteristics such as biphenotypic leukemia with B/myeloid cell antigens, Philadelphia translocation (BCR-ABL1 mutation), and response to acute lymphoblastic leukemia-type chemotherapy. These similarities suggest the presence of hereditary factors contributing to the development of MPAL. Targeted sequencing identified shared germline variants in these cases; however, in silico analyses did not strongly support their pathogenicity. Intriguingly, when the son developed MPAL, the mother did not develop donor-derived leukemia and remained in remission. Our cases provide valuable insights to guide future research on familial MPAL.

Impaired binding affinity of YTHDC1 with METTL3/METTL14 results in R-loop accumulation in myelodysplastic neoplasms with DDX41 mutation

DEAD box helicase 41 (DDX41) mutations are the most prevalent predisposition to familial myelodysplastic syndrome (MDS). However, the precise roles of these variants in the pathogenesis of MDS have yet to be elucidated. Here, we discovered a novel mechanism by which DDX41 contributes to R-loop-induced DNA damage responses (DDR) in cooperation with the m6A-METTL complex (MAC) and YTHDC1 using DDX41 knockout (KO) and DDX41 knock-in (KI, R525H, Y259C) cell lines as well as primary samples from MDS patients. Compared to wild type (WT), DDX41 KO and KI led to increased levels of m6A RNA methylated R-loop. Interestingly, we found that DDX41 regulates m6A/R-loop levels by interacting with MAC components. Further, DDX41 promoted the recruitment of YTHDC1 to R-loops by promoting the binding between METTL3 and YTHDC1, which was dysregulated in DDX41-deficient cells, contributing to genomic instability. Collectively, we demonstrated that DDX41 plays a key role in the physiological control of R-loops in cooperation with MAC and YTHDC1. These findings provide novel insights into how defects in DDX41 influence MDS pathogenesis and suggest potential therapeutic targets for the treatment of MDS.

Pathogenic GATA2 genetic variants utilize an obligate enhancer mechanism to distort a multilineage differentiation program

Mutations in genes encoding transcription factors inactivate or generate ectopic activities to instigate pathogenesis. By disrupting hematopoietic stem/progenitor cells, GATA2 germline variants create a bone marrow failure and leukemia predisposition, GATA2 deficiency syndrome, yet mechanisms underlying the complex phenotypic constellation are unresolved. We used a GATA2-deficient progenitor rescue system to analyze how genetic variation influences GATA2 functions. Pathogenic variants impaired, without abrogating, GATA2-dependent transcriptional regulation. Variants promoted eosinophil and repressed monocytic differentiation without regulating mast cell and erythroid differentiation. While GATA2 and T354M required the DNA-binding C-terminal zinc finger, T354M disproportionately required the N-terminal finger and N terminus. GATA2 and T354M activated a CCAAT/Enhancer Binding Protein-ε (C/EBPε) enhancer, creating a feedforward loop operating with the T-cell Acute Lymphocyte Leukemia-1 (TAL1) transcription factor. Elevating C/EBPε partially normalized hematopoietic defects of GATA2-deficient progenitors. Thus, pathogenic germline variation discriminatively spares or compromises transcription factor attributes, and retaining an obligate enhancer mechanism distorts a multilineage differentiation program.

Unraveling germline predisposition in hematological neoplasms: Navigating complexity in the genomic era

Genomic advancements have yielded pivotal insights into hematological neoplasms, particularly concerning germline predisposition mutations. Following the WHO 2016 revisions, dedicated segments were proposed to address these aspects. Current WHO 2022, ICC 2022, and ELN 2022 classifications recognize their significance, introducing more mutations and prompting integration into clinical practice. Approximately 5-10% of hematological neoplasm patients show germline predisposition gene mutations, rising with risk factors such as personal cancer history and familial antecedents, even in older adults. Nevertheless, technical challenges persist. Optimal DNA samples are skin fibroblast-extracted, although not universally applicable. Alternatives such as hair follicle use are explored. Moreover, the scrutiny of germline genomics mandates judicious test selection to ensure precise and accurate interpretation. Given the significant influence of genetic counseling on patient care and post-assessment procedures, there arises a demand for dedicated centers offering specialized services.

Nucleic acid-induced inflammation on hematopoietic stem cells

Hematopoiesis, the process of generating blood cells, starts during development with the primitive, pro-definitive, and definitive hematopoietic waves. The first two waves will generate erythrocytes and myeloid cells, although the definitive wave will give rise to hematopoietic stem cells (HSCs) that are multipotent and can produce most of the blood cells in an adult. Although HSCs are highly proliferative during development, during adulthood they remain quiescent in the bone marrow. Inflammatory signaling in the form of interferons, interleukins, tumor necrosis factors, and others is well-established to influence both developmental and adult hematopoiesis. Here we discuss the role of specific inflammatory pathways that are induced by sensing nucleic acids. We discuss the role of RNA-sensing members of the Toll-like, Rig-I-like, nucleotide-binding oligomerization domain (NOD)-like, and AIM2-like protein kinase receptors and the DNA-sensing receptors, DEAD-Box helicase 41 (DDX41) and cGAS. The main downstream pathways of these receptors are discussed, as well as their influence on developmental and adult hematopoiesis, including hematopoietic pathologies.

DDX41: exploring the roles of a versatile helicase

DDX41 is a DEAD-box helicase and is conserved across species. Mutations in DDX41 have been associated with myeloid neoplasms, including myelodysplastic syndrome and acute myeloid leukemia. Though its pathogenesis is not completely known, DDX41 has been shown to have many cellular roles, including in pre-mRNA splicing, innate immune sensing, ribosome biogenesis, translational regulation, and R-loop metabolism. In this review, we will summarize the latest understandings regarding the various roles of DDX41, as well as highlight challenges associated with drug development to target DDX41. Overall, understanding the molecular and cellular mechanisms of DDX41 could help develop novel therapeutic options for DDX41 mutation-related hematologic malignancies.

Mass spectrometry-based proteomics of cerebrospinal fluid in pediatric central nervous system malignancies: a systematic review with meta-analysis of individual patient data

BACKGROUND

The cerebrospinal fluid (CSF) proteome could offer important insights into central nervous system (CNS) malignancies. To advance proteomic research in pediatric CNS cancer, the current study aims to (1) evaluate past mass spectrometry-based workflows and (2) synthesize previous CSF proteomic data, focusing on both qualitative summaries and quantitative re-analysis. MAIN: In our analysis of 11 studies investigating the CSF proteome in pediatric patients with acute lymphoblastic leukemia (ALL) or primary brain tumors, we observed significant methodological variability. This variability negatively affects comparative analysis of the included studies, as per GRADE criteria for quality of evidence. The qualitative summaries covered 161 patients and 134 non-tumor controls, while the application of validation cohort varied among the studies. The quantitative re-analysis comprised 15 B-ALL vs 6 "healthy" controls and 15 medulloblastoma patients vs 22 non-tumor controls. Certain CSF proteins were identified as potential indicators of specific malignancies or stages of neurotoxicity during chemotherapy, yet definitive conclusions were impeded by inconsistent data. There were no proteins with statistically significant differences when comparing cases versus controls that were corroborated across studies where quantitative reanalysis was feasible. From a gene ontology enrichment, we observed that age disparities between unmatched case and controls may mislead to protein correlations more indicative of age-related CNS developmental stages rather than neuro-oncological disease. Despite efforts to batch correct (HarmonizR) and impute missing values, merging of dataset proved unfeasible and thereby limited meaningful data integration across different studies.

CONCLUSION

Infrequent publications on rare pediatric cancer entities, which often involve small sample sizes, are inherently prone to result in heterogeneous studies-particularly when conducted within a rapidly evolving field like proteomics. As a result, obtaining clear evidence, such as CSF proteome biomarkers for CNS dissemination or early-stage neurotoxicity, is currently impractical. Our general recommendations comprise the need for standardized methodologies, collaborative efforts, and improved data sharing in pediatric CNS malignancy research. We specifically emphasize the possible importance of considering natural age-related variations in CSF due to different CNS development stages when matching cases and controls in future studies.

Clonal hematopoiesis in the setting of hematopoietic cell transplantation

Clonal hematopoiesis (CH) in autologous transplant recipients and allogeneic transplant donors has genetic features and clinical associations that are distinct from each other and from non-cancer populations. CH in the setting of autologous transplant is enriched for mutations in DNA damage response pathway genes and is associated with adverse outcomes, including an increased risk of therapy-related myeloid neoplasm and inferior overall survival. Studies of CH in allogeneic transplant donors have yielded conflicting results but have generally shown evidence of potentiated alloimmunity in recipients, with some studies showing an association with favorable recipient outcomes.

Germline Variants and Characteristic Features of Hereditary Hematological Malignancy Syndrome

Due to the proliferation of genetic testing, pathogenic germline variants predisposing to hereditary hematological malignancy syndrome (HHMS) have been identified in an increasing number of genes. Consequently, the field of HHMS is gaining recognition among clinicians and scientists worldwide. Patients with germline genetic abnormalities often have poor outcomes and are candidates for allogeneic hematopoietic stem cell transplantation (HSCT). However, HSCT using blood from a related donor should be carefully considered because of the risk that the patient may inherit a pathogenic variant. At present, we now face the challenge of incorporating these advances into clinical practice for patients with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) and optimizing the management and surveillance of patients and asymptomatic carriers, with the limitation that evidence-based guidelines are often inadequate. The 2016 revision of the WHO classification added a new section on myeloid malignant neoplasms, including MDS and AML with germline predisposition. The main syndromes can be classified into three groups. Those without pre-existing disease or organ dysfunction; DDX41, TP53, CEBPA, those with pre-existing platelet disorders; ANKRD26, ETV6, RUNX1, and those with other organ dysfunctions; SAMD9/SAMD9L, GATA2, and inherited bone marrow failure syndromes. In this review, we will outline the role of the genes involved in HHMS in order to clarify our understanding of HHMS.

Case Report of a DDX41 Germline Mutation in a Family with Multiple Relatives Suffering from Leukemia

INTRODUCTION

Previously, it was assumed that genetic influence played a minor role in acute myeloid leukemia (AML). Increasing evidence of germline mutations has emerged, such as DDX41 germline mutation associated with familial AML.

CASE PRESENTATION

A 64-year-old male patient presented with reduced exercise tolerance and shortness of breath. Following confirmation of AML diagnosis, the patient was enrolled into the AMLSG-30-18 study with a requirement for allogenic stem cell transplantation. The sister was initially selected as a fully HLA-matched donor. However, the family history showed risks for familial AML. Due to the striking family history, further diagnostic steps were initiated to detect a germline mutation.

METHODS

Using NGS in the patients' bone marrow AML sample, a DDX41 mutation with a VAF of 49% was detected, raising the possibility of a germline mutation. DNA from cheek swabs and eyebrows were tested for the presence of the DDX41 mutation in all siblings.

RESULTS

DDX41 germline mutation was detected in 5 out of 6 siblings. The sister was excluded as a related donor and the search for an unrelated donor was initiated.

CONCLUSION

Obtaining family history of cancer patients plays a crucial role in oncology. If a germline mutation is suspected, further family work-up should be initiated.

The clinical and genomic landscape of patients with DDX41 variants identified during diagnostic sequencing

Deleterious germ line variants in DDX41 are a common cause of genetic predisposition to hematologic malignancies, particularly myelodysplastic neoplasms (MDS) and acute myeloid leukemia (AML). Targeted next-generation sequencing was performed in a large cohort of sequentially recruited patients with myeloid malignancy, covering DDX41 as well as 30 other genes frequently mutated in myeloid malignancy. Whole genome transcriptome sequencing data was analyzed on a separate cohort of patients with a range of hematologic malignancies to investigate the spectrum of cancer predisposition. Altogether, 5737 patients with myeloid malignancies were studied, with 152 different DDX41 variants detected. Multiple novel variants were detected, including synonymous variants affecting splicing as demonstrated by RNA-sequencing. The presence of a somatic DDX41 variant was highly associated with DDX41 germ line variants in patients with MDS and AML, and we developed a statistical approach to incorporate the co-occurrence of a somatic DDX41 variant into germ line variant classification at a very strong level (as per the American College of Medical Genetics and Genomics/Association for Molecular Pathology guidelines). Using this approach, the MDS cohort contained 108 of 2865 (3.8%) patients with germ line likely pathogenic/pathogenic (LP/P) variants, and the AML cohort 106 of 2157 (4.9%). DDX41 LP/P variants were markedly enriched in patients with AML and MDS compared with those in patients with myeloproliferative neoplasms, B-cell neoplasm, and T- or B-cell acute lymphoblastic leukemia. In summary, we have developed a framework to enhance DDX41 variant curation as well as highlighted the importance of assessment of all types of genomic variants (including synonymous and multiexon deletions) to fully detect the landscape of possible clinically relevant DDX41 variants.

Clonal evolution in inherited marrow failure syndromes predicts disease progression

Progression to myelodysplastic syndromes (MDS) and acute myeloid leukemia is one of the most serious complications of the inherited bone marrow failure and MDS-predisposition syndromes. Given the lack of predictive markers, this risk can also be a source of great uncertainty and anxiety to patients and their providers alike. Recent data show that some acquired mutations may provide a window into this risk. While maladaptive mechanisms, such as monosomy 7, are associated with a high risk of leukemogenesis, mutations that offset the inherited defect (known as somatic genetic rescue) may attenuate this risk. Somatic mutations that are shared with age-acquired clonal hematopoiesis mutations also show syndrome-specific patterns that may provide additional data as to disease risk. This review focuses on recent progress in this area with an emphasis on the biological underpinnings and interpretation of these patterns for patient care decisions.

Germline predisposition traits in allogeneic hematopoietic stem-cell transplantation for myelodysplastic syndromes: a survey-based study and position paper on behalf of the Chronic Malignancies Working Party of the EBMT

The recent application of whole exome or whole genome sequencing unveiled a plethora of germline variants predisposing to myeloid disorders, particularly myelodysplastic neoplasms. The presence of such variants in patients with myelodysplastic syndromes has important clinical repercussions for haematopoietic stem-cell transplantation, from donor selection and conditioning regimen to graft-versus-host disease prophylaxis and genetic counselling for relatives. No international guidelines exist to harmonise management approaches to this particular clinical scenario. Moreover, the application of germline testing, and how this informs clinical decisions, differs according to the expertise of individual clinical practices and according to different countries, health-care systems, and legislations. Leveraging the global span of the European Society for Blood and Marrow Transplantation (EBMT) network, we took a snapshot of the current European situation on these matters by disseminating an electronic survey to EBMT centres experienced in myelodysplastic syndromes transplantation. An international group of haematologists, transplantation physicians, paediatricians, nurses, and experts in molecular biology and constitutional genetics with experience in myelodysplastic syndromes contributed to this Position Paper. The panel met during multiple online meetings to discuss the results of the EBMT survey and to establish suggested harmonised guidelines for such clinical situations, which are presented here.

Identifying patients at risk for hereditary myeloid malignancy syndromes incorporating a novel, self-administered questionnaire to an initial screening platform

INTRODUCTION

Four to 10% of cases of myeloid malignancies are inherited. We report our experience on hereditary myeloid malignancy syndromes (HMMS) incorporating a novel questionnaire in the screening platform for patients with myeloid malignancies and aplastic anemia.

METHODS

The questionnaire was sent via electronic patient portal prior to clinic visits. Patients screened positive based on responses to questionnaire items, presence of suspicion disease characteristics (young age, family history, monosomy 7 etc.) and/or presence of signs of HMMS. Those deemed at-risk based on questionnaire responses, clinical features and/or somatic mutation profile were offered germline testing.

RESULTS

A total of 408 patients were screened, 141 (35%) were deemed at-risk. Fifty-four (38%) of at-risk patients were seen in the genetics clinic. Forty-one (76%) of the patients seen agreed to germline testing and 13 declined due to cost or personal decision. Twenty pathogenic (P)/likely-pathogenic (LP) germline mutations were identified in 16 (39%) of the tested patients. Five patients also had a variant of uncertain significance (VUS) and an additional 13 had at least 1 VUS without P/LP mutations (total 29 VUS's were found in 18 (44%) of tested patients). The median age of diagnosis for patients with P/LP mutations was 56 years versus 66 years in the entire cohort.

CONCLUSION

Incorporating an electronic questionnaire is an effective screening method for HMMS. Many patients declined testing due to cost. These results highlight the importance of germline testing in patients with myeloid malignancies, further research in HMMS, and coverage by healthcare plans.

Clinical and molecular correlates of somatic and germline DDX41 variants in patients and families with myeloid neoplasms

The diagnosis of germline predisposition to myeloid neoplasms (MN) secondary to DDX41 variants is currently hindered by the long latency period, variable family histories and the frequent occurrence of DDX41 variants of uncertain significance (VUS). We reviewed 4,524 consecutive patients who underwent targeted sequencing for suspected or known MN and analyzed the clinical impact and relevance of DDX41VUS in comparison to DDX41path variants. Among 107 patients (44 [0.9%] DDX41path and 63 DDX41VUS [1.4%; 11 patients with both DDX41path and DDX41VUS]), we identified 17 unique DDX41path and 45 DDX41VUS variants: 24 (23%) and 77 (72%) patients had proven and presumed germline DDX41 variants, respectively. The median age was similar between DDX41path and DDX41VUS (66 vs. 62 years; P=0.41). The median variant allele frequency (VAF) (47% vs. 48%; P=0.62), frequency of somatic myeloid co-mutations (34% vs 25%; P= 0.28), cytogenetic abnormalities (16% vs. 12%; P=>0.99) and family history of hematological malignancies (20% vs. 33%; P=0.59) were comparable between the two groups. Time to treatment in months (1.53 vs. 0.3; P=0.16) and proportion of patients progressing to acute myeloid leukemia (14% vs. 11%; P=0.68), were similar. The median overall survival in patients with high-risk myelodysplastic syndrome/acute myloid leukemia was 63.4 and 55.7 months in the context of DDX41path and DDX41VUS, respectively (P=0.93). Comparable molecular profiles and clinical outcomes among DDX41path and DDX41VUS patients highlights the need for a comprehensive DDX41 variant interrogation/classification system, to improve surveillance and management strategies in patients and families with germline DDX41 predisposition syndromes.

'From R-lupus to cancer': Reviewing the role of R-loops in innate immune responses

Cells possess an inherent and evolutionarily conserved ability to detect and respond to the presence of foreign and pathological 'self' nucleic acids. The result is the stimulation of innate immune responses, signalling to the host immune system that defence mechanisms are necessary to protect the organism. To date, there is a vast body of literature describing innate immune responses to various nucleic acid species, including dsDNA, ssDNA and ssRNA etc., however, there is limited information available on responses to R-loops. R-loops are 3-stranded nucleic acid structures that form during transcription, upon DNA damage and in various other settings. Emerging evidence suggests that innate immune responses may also exist for the detection of R-loop related nucleic acid structures, implicating R-loops as drivers of inflammatory states. In this review, we aim to summarise the evidence indicating that R-loops are immunogenic species that can trigger innate immune responses in physiological and pathological settings and discuss the implications of this in the study of various diseases and therapeutic development.

Diagnostic work-up of hematological malignancies with underlying germline predisposition disorders (GPD)

Hematological malignancies with underlying germline predisposition disorders have been recognized by the World Health Organization 5th edition and International Consensus Classification (ICC) classification systems. The list of genes and the associated phenotypes are expanding and involve both pediatric and adult populations. While the clinical presentation and underlying molecular pathogenesis are relatively well described, the knowledge regarding the bone marrow morphologic features, the landscape of somatic aberrations associated with progression to hematological malignancies is limited. These pose challenges in the diagnosis of low-grade myelodysplastic syndrome (MDS) to hematopathologists which carries direct implication for various aspects of clinical management of the patient, donor selection for transplantation, and family members. Here in, we provide a focused review on the diagnostic work-up of hematological malignancies with underlying germline predisposition disorders with emphasis on the spectrum of hematological malignancies associated with each entity, and characteristic bone marrow morphologic, somatic cytogenetic and molecular alterations at the time of diagnosis of hematological malignancies. We also review the key clinical, morphologic, and molecular features, that should initiate screening for these entities.

Characteristics and clinical outcomes of patients with myeloid malignancies and DDX41 variants

DDX41 is the most frequently mutated gene in myeloid neoplasms associated with germline predisposition including myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). We analyzed 3795 patients with myeloid neoplasms and identified 151 (4%) with DDX41 variants and a diagnosis of AML (n = 96), MDS (n = 52), and chronic myelomonocytic leukemia (n = 3). The most frequent DDX41 variants were the somatic variant p.R525H, followed by the germline variants p.M1I and p.D140fs. Most neoplasms had a normal karyotype (59%) and the most frequent co-mutations were TP53 (16%) and ASXL1 (15%). 30% of patients had no concomitant mutations besides DDX41 mutation. Patients with myeloid malignancies and DDX41 variants responded well to therapy, with an overall response rate for patients with treatment naïve AML and MDS of 87% and 84%, respectively. The median overall survival (mOS) of patients with treatment-naïve AML or MDS was 49 and 71 months, respectively. Patients with AML treated with low-intensity regimens including venetoclax had an improved survival (2-year OS 91% vs. 60%, p = .02) and lower cumulative incidence of relapse compared to those treated without venetoclax (10% vs. 56%, p = .03). In the 33% of patients receiving hematopoietic stem cell transplantation, the 2-year OS was 80% and 85% for AML and MDS, respectively.

Somatic mutational landscape of hereditary hematopoietic malignancies caused by germline variants in RUNX1, GATA2, and DDX41

Individuals with germ line variants associated with hereditary hematopoietic malignancies (HHMs) have a highly variable risk for leukemogenesis. Gaps in our understanding of premalignant states in HHMs have hampered efforts to design effective clinical surveillance programs, provide personalized preemptive treatments, and inform appropriate counseling for patients. We used the largest known comparative international cohort of germline RUNX1, GATA2, or DDX41 variant carriers without and with hematopoietic malignancies (HMs) to identify patterns of genetic drivers that are unique to each HHM syndrome before and after leukemogenesis. These patterns included striking heterogeneity in rates of early-onset clonal hematopoiesis (CH), with a high prevalence of CH in RUNX1 and GATA2 variant carriers who did not have malignancies (carriers-without HM). We observed a paucity of CH in DDX41 carriers-without HM. In RUNX1 carriers-without HM with CH, we detected variants in TET2, PHF6, and, most frequently, BCOR. These genes were recurrently mutated in RUNX1-driven malignancies, suggesting CH is a direct precursor to malignancy in RUNX1-driven HHMs. Leukemogenesis in RUNX1 and DDX41 carriers was often driven by second hits in RUNX1 and DDX41, respectively. This study may inform the development of HHM-specific clinical trials and gene-specific approaches to clinical monitoring. For example, trials investigating the potential benefits of monitoring DDX41 carriers-without HM for low-frequency second hits in DDX41 may now be beneficial. Similarly, trials monitoring carriers-without HM with RUNX1 germ line variants for the acquisition of somatic variants in BCOR, PHF6, and TET2 and second hits in RUNX1 are warranted.

Germline and somatic drivers in inherited hematologic malignancies

Inherited hematologic malignancies are linked to a heterogenous group of genes, knowledge of which is rapidly expanding using panel-based next-generation sequencing (NGS) or whole-exome/whole-genome sequencing. Importantly, the penetrance for these syndromes is incomplete, and disease development, progression or transformation has critical clinical implications. With the earlier detection of healthy carriers and sequential monitoring of these patients, clonal hematopoiesis and somatic driver variants become significant factors in determining disease transformation/progression and timing of (preemptive) hematopoietic stem cell transplant in these patients. In this review, we shed light on the detection of probable germline predisposition alleles based on diagnostic/prognostic 'somatic' NGS panels. A multi-tier approach including variant allele frequency, bi-allelic inactivation, persistence of a variant upon clinical remission and mutational burden can indicate variants with high pre-test probability. We also discuss the shared underlying biology and frequency of germline and somatic variants affecting the same gene, specifically focusing on variants in DDX41, ETV6, GATA2 and RUNX1. Germline variants in these genes are associated with a (specific) pattern or over-/underrepresentation of somatic molecular or cytogenetic alterations that may help identify the underlying germline syndrome and predict the course of disease in these individuals. This review is based on the current knowledge about somatic drivers in these four syndromes by integrating data from all published patients, thereby providing clinicians with valuable and concise information.

Prevalence and significance of DDX41 gene variants in the general population

Germ line variants in the DDX41 gene have been linked to myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) development. However, the risks associated with different variants remain unknown, as do the basis of their leukemogenic properties, impact on steady-state hematopoiesis, and links to other cancers. Here, we investigate the frequency and significance of DDX41 variants in 454 792 United Kingdom Biobank (UKB) participants and identify 452 unique nonsynonymous DNA variants in 3538 (1/129) individuals. Many were novel, and the prevalence of most varied markedly by ancestry. Among the 1059 individuals with germ line pathogenic variants (DDX41-GPV) 34 developed MDS/AML (odds ratio, 12.3 vs noncarriers). Of these, 7 of 218 had start-lost, 22 of 584 had truncating, and 5 of 257 had missense (odds ratios: 12.9, 15.1, and 7.5, respectively). Using multivariate logistic regression, we found significant associations of DDX41-GPV with MDS, AML, and family history of leukemia but not lymphoma, myeloproliferative neoplasms, or other cancers. We also report that DDX41-GPV carriers do not have an increased prevalence of clonal hematopoiesis (CH). In fact, CH was significantly more common before sporadic vs DDX41-mutant MDS/AML, revealing distinct evolutionary paths. Furthermore, somatic mutation rates did not differ between sporadic and DDX41-mutant AML genomes, ruling out genomic instability as a driver of the latter. Finally, we found that higher mean red cell volume (MCV) and somatic DDX41 mutations in blood DNA identify DDX41-GPV carriers at increased MDS/AML risk. Collectively, our findings give new insights into the prevalence and cognate risks associated with DDX41 variants, as well as the clonal evolution and early detection of DDX41-mutant MDS/AML.

How I diagnose myeloid neoplasms with germline predisposition

OBJECTIVES

Pathologists play a crucial role in the initial diagnosis of germline predisposition to myeloid neoplasia and subsequent surveillance for disease progression. The diagnostic workup can be challenging, particularly if clinical history, laboratory testing, or genetic studies are incomplete or unavailable.

METHODS

Through case-based examples, we illustrate common diagnostic challenges and pitfalls encountered during bone marrow examination of patients being evaluated for myeloid malignancy with potential germline predisposition to myeloid neoplasia.

RESULTS

Lack of familial disease, the absence of syndromic manifestations, and late-onset hematologic malignancy do not exclude an underlying germline predisposition syndrome. Targeted myeloid sequencing panels can help identify potential germline alterations but may not detect large deletions or insertions, noncoding, or novel variants. Confirmation of the germline nature of an alteration detected in the peripheral blood or bone marrow ideally requires genetic testing using nonhematopoietic germline DNA to definitively distinguish between germline and somatic alterations. The ideal tissue source for germline testing is cultured skin fibroblasts. Certain germline predisposition syndromes can contain characteristic baseline bone marrow dysplastic-appearing features associated with cytopenias without constituting myelodysplastic syndrome.

CONCLUSION

Recognizing germline predisposition to myeloid neoplasia is critical for proper disease management. This recognition is particularly important for patients who will undergo hematopoietic stem cell transplantation to screen potential related donors. Integration of the clinical history, bone marrow findings, cytogenetic studies, and specialized laboratory and molecular genetic testing is often essential for accurate diagnosis and subsequent disease monitoring.

Allogeneic Hematopoietic Cell Transplantation Improves Outcome in Myelodysplastic Syndrome Across High-Risk Genetic Subgroups: Genetic Analysis of the Blood and Marrow Transplant Clinical Trials Network 1102 Study

PURPOSE

Allogeneic hematopoietic cell transplantation (HCT) in patients with myelodysplastic syndrome (MDS) improves overall survival (OS). We evaluated the impact of MDS genetics on the benefit of HCT in a biological assignment (donor v no donor) study.

METHODS

We performed targeted sequencing in 309 patients age 50-75 years with International Prognostic Scoring System (IPSS) intermediate-2 or high-risk MDS, enrolled in the Blood and Marrow Transplant Clinical Trials Network 1102 study and assessed the association of gene mutations with OS. Patients with TP53 mutations were classified as TP53multihit if two alleles were altered (via point mutation, deletion, or copy-neutral loss of heterozygosity).

RESULTS

The distribution of gene mutations was similar in the donor and no donor arms, with TP53 (28% v 29%; P = .89), ASXL1 (23% v 29%; P = .37), and SRSF2 (16% v 16%; P = .99) being most common. OS in patients with a TP53 mutation was worse compared with patients without TP53 mutation (21% ± 5% [SE] v 52% ± 4% at 3 years; P < .001). Among those with a TP53 mutation, OS was similar between TP53single versus TP53multihit (22% ± 8% v 20% ± 6% at 3 years; P = .31). Considering HCT as a time-dependent covariate, patients with a TP53 mutation who underwent HCT had improved OS compared with non-HCT treatment (OS at 3 years: 23% ± 7% v 11% ± 7%; P = .04), associated with a hazard ratio of 3.89; 95% CI, 1.87 to 8.12; P < .001 after adjustment for covariates. OS among patients with molecular IPSS (IPSS-M) very high risk without a TP53 mutation was significantly improved if they had a donor (68% ± 10% v 0% ± 12% at 3 years; P = .001).

CONCLUSION

HCT improved OS compared with non-HCT treatment in patients with TP53 mutations irrespective of TP53 allelic status. Patients with IPSS-M very high risk without a TP53 mutation had favorable outcomes when a donor was available.

Cytogenetics in the management of hematologic neoplasms with germline predisposition: guidelines from the Groupe Francophone de Cytogénétique Hématologique (GFCH)

The number of predisposing genes is continuously growing with the widespread availability of DNA sequencing, increasing the prevalence of hematologic malignancies with germline predisposition. Cytogenetic analyses provide an effective approach for the recognition of these malignancies with germline predisposition, which is critical for proper diagnosis, optimal treatment and genetic counseling. Based on the World Health Organization and the international consensus classifications as well as the European LeukemiaNet recommendations, this review first presents an advanced classification of neoplasms with germline predisposition focused on the acquired cytogenetic alterations during leukemogenesis. The various genetic rescue mechanisms and the progression to transformation are then explained. The review also outlines the specific constitutional and somatic cytogenetic aberrations indicative of germline predisposition disorders in B-acute lymphoblastic leukemia (ALL), T-ALL, bone marrow failure syndrome and myeloid neoplasms. An emphasis is made on monosomy 7 in the predisposition field, its frequency and diagnosis impact as well as its various circumstances of occurrence. Lastly, we propose cytogenetic technical recommendations and guidelines for clinical reporting of these specific aberrations.

Prevalence and clinical expression of germ line predisposition to myeloid neoplasms in adults with marrow hypocellularity

Systematic studies of germ line genetic predisposition to myeloid neoplasms in adult patients are still limited. In this work, we performed germ line and somatic targeted sequencing in a cohort of adult patients with hypoplastic bone marrow (BM) to study germ line predisposition variants and their clinical correlates. The study population included 402 consecutive adult patients investigated for unexplained cytopenia and reduced age-adjusted BM cellularity. Germ line mutation analysis was performed using a panel of 60 genes, and variants were interpreted per the American College of Medical Genetics and Genomics/Association for Molecular Pathology guidelines; somatic mutation analysis was performed using a panel of 54 genes. Of the 402 patients, 27 (6.7%) carried germ line variants that caused a predisposition syndrome/disorder. The most frequent disorders were DDX41-associated predisposition, Fanconi anemia, GATA2-deficiency syndrome, severe congenital neutropenia, RASopathy, and Diamond-Blackfan anemia. Eighteen of 27 patients (67%) with causative germ line genotype were diagnosed with myeloid neoplasm, and the remaining with cytopenia of undetermined significance. Patients with a predisposition syndrome/disorder were younger than the remaining patients and had a higher risk of severe or multiple cytopenias and advanced myeloid malignancy. In patients with myeloid neoplasm, causative germ line mutations were associated with increased risk of progression into acute myeloid leukemia. Family or personal history of cancer did not show significant association with a predisposition syndrome/disorder. The findings of this study unveil the spectrum, clinical expressivity, and prevalence of germ line predisposition mutations in an unselected cohort of adult patients with cytopenia and hypoplastic BM.

Needle in a haystack or elephant in the room? Identifying germline predisposition syndromes in the setting of a new myeloid malignancy diagnosis

Myeloid malignancies associated with germline predisposition syndromes account for up to 10% of myeloid neoplasms. They are classified into three categories by the proposed 5th Edition of the World Health Organization Classification of Hematolymphoid Tumors: (1) neoplasms with germline predisposition without a pre-existing platelet disorder or organ dysfunction, (2) neoplasms with germline predisposition and pre-existing platelet disorder, or (3) neoplasms with germline predisposition and potential organ dysfunction. Recognizing these entities is critical because patients and affected family members benefit from interfacing with hematologists who specialize in these disorders and can facilitate tailored treatment strategies. However, identification of these syndromes in routine pathology practice is often challenging, as characteristic findings associated with these diagnoses at baseline are frequently absent, nonspecific, or impossible to evaluate in the setting of a myeloid malignancy. Here we review the formally classified germline predisposition syndromes associated with myeloid malignancies and summarize practical recommendations for pathologists evaluating a new myeloid malignancy diagnosis. Our intent is to empower clinicians to better screen for germline disorders in this common clinical setting. Recognizing when to suspect a germline predisposition syndrome, pursue additional ancillary testing, and ultimately recommend referral to a cancer predisposition clinic or hematology specialist, will ensure optimal patient care and expedite research to improve outcomes for these individuals.

Current landscape of translational and clinical research in myelodysplastic syndromes/neoplasms (MDS): Proceedings from the 1st International Workshop on MDS (iwMDS) Of the International Consortium for MDS (icMDS)

Biological events that contribute to the pathogenesis of myelodysplastic syndromes/neoplasms (MDS) are becoming increasingly characterized and are being translated into rationally designed therapeutic strategies. Herein, we provide updates from the first International Workshop on MDS (iwMDS) of the International Consortium for MDS (icMDS) detailing recent advances in understanding the genetic landscape of MDS, including germline predisposition, epigenetic and immune dysregulation, the complexities of clonal hematopoiesis progression to MDS, as well as novel animal models of the disease. Connected to this progress is the development of novel therapies targeting specific molecular alterations, the innate immune system, and immune checkpoint inhibitors. While some of these agents have entered clinical trials (e.g., splicing modulators, IRAK1/4 inhibitors, anti-CD47 and anti-TIM3 antibodies, and cellular therapies), none have been approved for MDS. Additional preclinical and clinical work is needed to develop a truly individualized approach to the care of MDS patients.

Expression and prognostic value of DNA sensors in hepatocellular carcinoma

DNA sensor proteins play an important role in transducing DNA signals to induce immune responses that initiate inflammation or clear pathogens. It has been previously shown that several DNA sensors are involved in regulating tumor biology and/or cancer immunology. However, a systemic analysis of DNA sensor expression and its correlation with prognosis has not been conducted. Here, we analyzed messenger RNA expression and protein abundance in liver cancer databases and found that the genes of 5 DNA sensors (POLR3A, PRKDC, DHX9, cGAS, and MRE11) were consistently upregulated in tumor tissue. Moreover, the expression of these DNA sensor genes correlated with patient survival. Using a gene alterations analysis, we discovered that patients with genetically altered DNA sensors had significantly lower survival compared with an unaltered group. Furthermore, receiver-operating characteristic curves confirmed that the signatures of the 5 DNA sensors were independent prognostic factors in hepatocellular carcinoma. Tumor-infiltrating immune cell analysis revealed that expression of all 5 DNA sensors correlated with the amount of B cells, CD8 T cells, CD4 T cells, Tregs, DCs, Mϕs, and neutrophils. Surprisingly, 4 of the DNA sensors (POLR3A, PRKDC, DHX9, and MRE11) were inversely correlated with the amount of γδ T cells. Gene set enrichment analysis showed that all 5 DNA sensor genes were enriched for oxidative phosphorylation and xenobiotic metabolism. These results suggest that expression of these DNA sensors is associated with a unique immune profile and metabolic regulation in hepatocellular carcinoma.

Therapeutic Targeting of RNA Splicing in Cancer

RNA splicing is a key regulatory step in the proper control of gene expression. It is a highly dynamic process orchestrated by the spliceosome, a macro-molecular machinery that consists of protein and RNA components. The dysregulation of RNA splicing has been observed in many human pathologies ranging from neurodegenerative diseases to cancer. The recent identification of recurrent mutations in the core components of the spliceosome in hematologic malignancies has advanced our knowledge of how splicing alterations contribute to disease pathogenesis. This review article will discuss our current understanding of how aberrant RNA splicing regulation drives tumor initiation and progression. We will also review current therapeutic modalities and highlight emerging technologies designed to target RNA splicing for cancer treatment.

Biallelic disruption of DDX41 activity is associated with distinct genomic and immunophenotypic hallmarks in acute leukemia

Introduction

Inherited DDX41 mutations cause familial predisposition to hematologic malignancies including acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), with the majority of DDX41 mutated MDS/AMLs described to date harboring germline DDX41 and co-occurring somatic DDX41 variants. DDX41-AMLs were shown to share distinguishing clinical features such as a late AML onset and an indolent disease associated with a favorable outcome. However, genotype-phenotype correlation in DDX41-MDS/AMLs remain poorly understood.

Methods

Here, we studied the genetic profile, bone marrow morphology and immunophenotype of 51 patients with DDX41 mutations. We further assessed the functional impact of ten previously uncharacterized DDX41 variants of uncertain significance.

Results

Our results demonstrate that MDS/AML cases harboring two DDX41 variants share specific clinicopathologic hallmarks that are not seen in other patients with monoallelic DDX41 related hematologic malignancies. We further showed that the features seen in these individuals with two DDX41 variants were concordant with biallelic DDX41 disruption.

Discussion

Here, we expand on previous clinicopathologic findings on DDX41 mutated hematologic malignancies. Functional analyses conducted in this study unraveled previously uncharacterized DDX41 alleles and further illustrate the implication of biallelic disruption in the pathophysiology of this distinct AML entity.

DHX9-mediated pathway contributes to the malignant phenotype of myelodysplastic syndromes

DHX9 is a member of the DEAH (Asp-Glu-Ala-His) helicase family and regulates DNA replication and RNA processing. DHX9 dysfunction promotes tumorigenesis in several solid cancers. However, the role of DHX9 in MDS is still unknown. Here, we analyzed the expression of DHX9 and its clinical significance in 120 MDS patients and 42 non-MDS controls. Lentivirus-mediated DHX9-knockdown experiments were performed to investigate its biological function. We also performed cell functional assays, gene microarray, and pharmacological intervention to investigate the mechanistic involvement of DHX9. We found that overexpression of DHX9 is frequent in MDS and associated with poor survival and high risk of acute myeloid leukemia (AML) transformation. DHX9 is essential for the maintenance of malignant proliferation of leukemia cells, and DHX9 suppression increases cell apoptosis and causes hypersensitivity to chemotherapeutic agents. Besides, knockdown of DHX9 inactivates the PI3K-AKT and ATR-Chk1 signaling, promotes R-loop accumulation, and R-loop-mediated DNA damage.

snoRNAs in hematopoiesis and blood malignancies: A comprehensive review

Small nucleolar RNAs (snoRNAs) are noncoding RNA molecules of highly variable size, usually ranging from 60 to 150 nucleotides. They are classified into H/ACA box snoRNAs, C/D box snoRNAs, and scaRNAs. Their functional profile includes biogenesis of ribosomes, processing of rRNAs, 2'-O-methylation and pseudouridylation of RNAs, alternative splicing and processing of mRNAs and the generation of small RNA molecules like miRNA. The snoRNAs have been observed to have an important role in hematopoiesis and malignant hematopoietic conditions including leukemia, lymphoma, and multiple myeloma. Blood malignancies arise in immune system cells or the bone marrow due to chromosome abnormalities. It has been estimated that annually over 1.25 million cases of blood cancer occur worldwide. The snoRNAs often show a differential expression profile in blood malignancies. Recent reports associate the abnormal expression of snoRNAs with the inhibition of apoptosis, uncontrolled cell proliferation, angiogenesis, and metastasis. This implies that targeting snoRNAs could be a potential way to treat hematologic malignancies. In this review, we describe the various functions of snoRNAs, their role in hematopoiesis, and the consequences of their dysregulation in blood malignancies. We also evaluate the potential of the dysregulated snoRNAs as biomarkers and therapeutic targets for blood malignancies.

Stagnation in quality of next-generation sequencing assays for the diagnosis of hereditary hematopoietic malignancies

Hereditary hematopoietic malignancies (HHMs) are inherited syndromes that confer the risk of blood cancer development. With the rapid acceleration of next-generation sequencing (NGS) into commercial biotechnology markets, HHMs are increasingly recognized by genetic counselors and clinicians. In 2020, it was demonstrated that most diagnostic test offerings for HHMs were insufficient for accurate diagnosis, failing to sequence the full spectrum of genetic events known to cause HHMs. We hypothesized the number of genes on commercially available HHM assay increased from 2020 to 2022, consistent with a more comprehensive sequencing approach. Here, we analyzed assays from eight commercial laboratories to determine the HHM-related genes sequenced by these assays. We compared these assays with panels from 2020 to determine trends in sequencing quality. Most HHM diagnostic assays did not change and remain insensitive for the detection of all HHM-related variants. Most (75%) HHM assays do not sequence CHEK2, the gene most frequently mutated in HHMs, and 25% of HHM assays does not sequence DDX41, the second most frequent HHM driver. The quality of HHM diagnostic assays stagnated despite the discovery of novel HHM-related genes and prior work demonstrating heterogeneity in the quality of HHM testing. Most commercially available HHM tests remain insufficient.

Germline Predisposition to Myelodysplastic Syndromes

ABSTRACT

While germline predisposition to myelodysplastic syndromes is well-established, knowledge has advanced rapidly resulting in more cases of inherited hematologic malignancies being identified. Understanding the biological features and main clinical manifestations of hereditary hematologic malignancies is essential to recognizing and referring patients with myelodysplastic syndrome, who may underlie inherited predisposition, for appropriate genetic evaluation. Importance lies in individualized genetic counseling along with informed treatment decisions, especially with regard to hematopoietic stem cell transplant-related donor selection. Future studies will improve comprehension of these disorders, enabling better management of affected patients and their families.

European standard clinical practice - Key issues for the medical care of individuals with familial leukemia

Although hematologic malignancies (HM) are no longer considered exclusively sporadic, additional awareness of familial cases has yet to be created. Individuals carrying a (likely) pathogenic germline variant (e.g., in ETV6, GATA2, SAMD9, SAMD9L, or RUNX1) are at an increased risk for developing HM. Given the clinical and psychological impact associated with the diagnosis of a genetic predisposition to HM, it is of utmost importance to provide high-quality, standardized patient care. To address these issues and harmonize care across Europe, the Familial Leukemia Subnetwork within the ERN PaedCan has been assigned to draft an European Standard Clinical Practice (ESCP) document reflecting current best practices for pediatric patients and (healthy) relatives with (suspected) familial leukemia. The group was supported by members of the German network for rare diseases MyPred, of the Host Genome Working Group of SIOPE, and of the COST action LEGEND. The ESCP on familial leukemia is proposed by an interdisciplinary team of experts including hematologists, oncologists, and human geneticists. It is intended to provide general recommendations in areas where disease-specific recommendations do not yet exist. Here, we describe key issues for the medical care of familial leukemia that shall pave the way for a future consensus guideline: (i) identification of individuals with or suggestive of familial leukemia, (ii) genetic analysis and variant interpretation, (iii) genetic counseling and patient education, and (iv) surveillance and (psychological) support. To address the question on how to proceed with individuals suggestive of or at risk of familial leukemia, we developed an algorithm covering four different, partially linked clinical scenarios, and additionally a decision tree to guide clinicians in their considerations regarding familial leukemia in minors with HM. Our recommendations cover, not only patients but also relatives that both should have access to adequate medical care. We illustrate the importance of natural history studies and the need for respective registries for future evidence-based recommendations that shall be updated as new evidence-based standards are established.

Deep genomic characterization highlights complexities and prognostic markers of pediatric acute myeloid leukemia

Pediatric acute myeloid leukemia (AML) is an uncommon but aggressive hematological malignancy. The poor outcome is attributed to inadequate prognostic classification and limited treatment options. A thorough understanding on the genetic basis of pediatric AML is important for the development of effective approaches to improve outcomes. Here, by comprehensively profiling fusion genes as well as mutations and copy number changes of 141 myeloid-related genes in 147 pediatric AML patients with subsequent variant functional characterization, we unveil complex mutational patterns of biological relevance and disease mechanisms including MYC deregulation. Also, our findings highlight TP53 alterations as strong adverse prognostic markers in pediatric AML and suggest the core spindle checkpoint kinase BUB1B as a selective dependency in this aggressive subgroup. Collectively, our present study provides detailed genomic characterization revealing not only complexities and mechanistic insights into pediatric AML but also significant risk stratification and therapeutic strategies to tackle the disease.

The Clinical Spectrum, Diagnosis, and Management of GATA2 Deficiency

Hereditary myeloid malignancy syndromes (HMMSs) are rare but are becoming increasingly significant in clinical practice. One of the most well-known syndromes within this group is GATA2 deficiency. The GATA2 gene encodes a zinc finger transcription factor essential for normal hematopoiesis. Insufficient expression and function of this gene as a result of germinal mutations underlie distinct clinical presentations, including childhood myelodysplastic syndrome and acute myeloid leukemia, in which the acquisition of additional molecular somatic abnormalities can lead to variable outcomes. The only curative treatment for this syndrome is allogeneic hematopoietic stem cell transplantation, which should be performed before irreversible organ damage happens. In this review, we will examine the structural characteristics of the GATA2 gene, its physiological and pathological functions, how GATA2 genetic mutations contribute to myeloid neoplasms, and other potential clinical manifestations. Finally, we will provide an overview of current therapeutic options, including recent transplantation strategies.

Targeting DEAD-box RNA helicases: The emergence of molecular staples

RNA helicases constitute a large family of proteins that play critical roles in mediating RNA function. They have been implicated in all facets of gene expression pathways involving RNA, from transcription to processing, transport and translation, and storage and decay. There is significant interest in developing small molecule inhibitors to RNA helicases as some family members have been documented to be dysregulated in neurological and neurodevelopment disorders, as well as in cancers. Although different functional properties of RNA helicases offer multiple opportunities for small molecule development, molecular staples have recently come to the forefront. These bifunctional molecules interact with both protein and RNA components to lock them together, thereby imparting novel gain-of-function properties to their targets. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Small Molecule-RNA Interactions RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.

Acute myeloid leukemia: 2023 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Acute myeloid leukemia (AML) is a frequently fatal bone marrow stem cell cancer characterized by unbridled proliferation of malignant marrow stem cells with associated infection, anemia, and bleeding. An improved understanding of pathophysiology, improvements in measurement technology and at least 10 recently approved therapies have led to revamping the diagnostic, prognostic, and therapeutic landscape of AML.

DIAGNOSIS

One updated and one new classification system were published in 2022, both emphasizing the integration of molecular analysis into daily practice. Differences between the International Consensus Classification and major revisions from the previous 2016 WHO system provide both challenges and opportunities for care and clinical research.

RISK ASSESSMENT AND MONITORING

The European Leukemia Net 2022 risk classification integrates knowledge from novel molecular findings and recent trial results, as well as emphasizing dynamic risk based on serial measurable residual disease assessment. However, how to leverage our burgeoning ability to measure a small number of potentially malignant myeloid cells into therapeutic decision making is controversial.

RISK ADAPTED THERAPY

The diagnostic and therapeutic complexity plus the availability of newly approved agents requires a nuanced therapeutic algorithm which should integrate patient goals of care, comorbidities, and disease characteristics including the specific mutational profile of the patient's AML. The framework we suggest only represents the beginning of the discussion.