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

Update on Recommendations for Surveillance for Children with Predisposition to Hematopoietic Malignancy

Children harboring certain germline gene variants have an increased risk of developing myelodysplastic syndrome (MDS) and other hematopoietic malignancies (HM), such as leukemias and lymphomas. Recent studies have identified an expanding number of these predisposition genes, with variants most prevalent in children with MDS but also found in children with other HM. For some hematopoietic malignancy predispositions (HMP), specifically those with a high risk of MDS, early intervention through hematopoietic stem cell transplantation can favorably impact overall survival, providing a rationale for rigorous surveillance. A multidisciplinary panel of experts at the 2023 AACR Childhood Cancer Predisposition Workshop reviewed the latest advances in the field and updated prior 2017 surveillance recommendations for children with HMP. In addition to general guidance for all children with HMP, which includes annual physical examination, education about the signs and symptoms of HM, consultation with experienced providers, and early assessment by a hematopoietic stem cell transplantation specialist, the panel provided specific recommendations for individuals with a higher risk of MDS based on the affected gene. These recommendations include periodic and comprehensive surveillance for individuals with those syndromes associated with higher risk of MDS, including serial bone marrow examinations to monitor for morphologic changes and deep sequencing for somatic changes in genes associated with HM progression. This approach enables close monitoring of disease evolution based on the individual's genetic profile. As more HMP-related genes are discovered and the disorders' natural histories are better defined, these personalized recommendations will serve as a foundation for future guidelines in managing these conditions.

Molecular pathophysiology of germline mutations in acute myeloid leukemia

Germline (GL) predisposition to acute myeloid leukemia (AML) has been established as an independent disease entity in the latest World Health Organization classification. Following the American College of Medical Genetics and Genomics guidelines, GL variants were interpreted as causal if they were classified as "pathogenic." GL predisposition can be divided into three groups with different phenotypes, and play an important role in the pathogenesis of adult-onset AML. The clinical course and age of onset of myeloid neoplasms varied considerably for each gene. For example, patients with GATA2 GL variants develop AML before the age of 30 along with bone marrow failure, whereas those with DDX41 GL variants tend to develop AML after the age of 50 without any preceding hematological abnormalities or organ dysfunction. A comprehensive analysis of adult-onset myelodysplastic syndromes in transplant donors showed a 7% frequency of pathogenic GL variants, with DDX41 being the most frequent gene mutation at approximately 3.8%. Future research on GL predisposition at any age of myeloid neoplasm onset will assist in early and accurate diagnosis, development of effective treatment strategies, and selection of suitable donors for stem cell transplantation.

Advances in pathogenesis research and challenges in treatment development for acute myeloid leukemia

Acute myeloid leukemia (AML) develops when hematopoietic stem cells acquire chromosomal and genetic abnormalities, transforming into leukemia stem cells (LSCs) and further gaining driver mutations. Advances in genomic analysis have identified numerous new gene mutations involved in AML development. Recent research has shown that individuals with germline mutations in genes like DDX41 and CEBPA develop AML upon acquiring additional somatic mutations, and the latest WHO classification separates AML with such mutations into distinct disease groups. LSCs are regulated by different metabolic processes than normal stem cells, contributing to drug resistance and relapse. LSCs rely on oxidative phosphorylation (OXPHOS) metabolism for energy production, and venetoclax inhibits this process, affecting LSCs. Resistant LSCs show enhanced glycolysis, which suggests that targeting both OXPHOS and glycolysis is crucial. While targeted therapies like FLT3, BCL-2, and IDH inhibitors have shown efficacy, resistance remains an issue, highlighting the need for new treatment strategies. CAR-T cell therapy is an emerging immunotherapy that shows particular promise for targeting CD123 and CLL-1, with acceptable toxicity. Future developments in CAR-T cell therapy and other immunotherapies are anticipated to improve AML treatment outcomes.

How we diagnose Myelodysplastic syndromes

The Myelodysplastic syndromes (MDS) are a heterogenous group of clonal bone marrow (BM) stem cell myeloid neoplasms, characterized by ineffective hematopoiesis that results in dysplasia in hematopoietic cells and peripheral cytopenias, especially anemia, and a propensity to leukemic transformation. The suspicion of MDS is raised by a typical but not specific clinical picture and routine laboratory findings, but the gold standard for MDS diagnosis is still BM examination with the presence of uni-or multi-lineage dysplasia and increased blast percentage, together with exclusion of other reasons. Cytogenetics is also an essential part of the diagnostic and prognostic processes. Flow cytometry and full genetic characterization are helpful but not mandatory for MDS diagnosis. This review summarizes the current steps of diagnostic approach for a patient suspected of having MDS. We also express our hopes that within the near future, non-invasive technologies, especially digital and peripheral blood genetics, will mature and be introduced into practice.

FLT3 Agonists and Secondary Hematopoietic Malignancies: A Potential Class Effect

Expansion of conventional dendritic cells via FMS-like tyrosine kinase 3 agonism has promising therapeutic potential in the treatment of advanced solid tumors. In this study, we discuss the results of a clinical trial using GS-3583, an FMS-like tyrosine kinase 3 agonist, that was stopped after a patient in the study developed acute myeloid leukemia. See related article by Tolcher et al., p. 2954.

Insights into the Molecular Mechanisms of Genetic Predisposition to Hematopoietic Malignancies: The Importance of Gene-Environment Interactions

SUMMARY

The recognition of host genetic factors underlying susceptibility to hematopoietic malignancies has increased greatly over the last decade. Historically, germline predisposition was thought to primarily affect the young. However, emerging data indicate that hematopoietic malignancies that develop in people of all ages across the human lifespan can derive from germline predisposing conditions and are not exclusively observed in younger individuals. The age at which hematopoietic malignancies manifest appears to correlate with distinct underlying biological pathways. Progression from having a deleterious germline variant to being diagnosed with overt malignancy involves complex, multistep gene-environment interactions with key external triggers, such as infection and inflammatory stimuli, driving clonal progression. Understanding the mechanisms by which predisposed clones transform under specific pressures may reveal strategies to better treat and even prevent hematopoietic malignancies from occurring.Recent unbiased genome-wide sequencing studies of children and adults with hematopoietic malignancies have revealed novel genes in which disease-causing variants are of germline origin. This paradigm shift is spearheaded by findings in myelodysplastic syndrome/acute myeloid leukemia (MDS/AML) as well as acute lymphoblastic leukemia, but it also encompasses other cancer types. Although not without challenges, the field of genetic cancer predisposition is advancing quickly, and a better understanding of the genetic basis of hematopoietic malignancies risk affects therapeutic decisions as well as genetic counseling and testing of at-risk family members.

Chronic low salinity stress rescued masculinization effect in farmed Cynoglossus semilaevis population

Salinity, being an indispensable abiotic factor crucial for the survival of marine organisms, has demonstrated diverse alterations globally in response to the current trend of global warming. In this study, the effect of chronic low salinity stress on teleosts' sex differentiation was investigated using Cynoglossus semilaevis, an economically important fish with both genetic and environmental sex determination system. The cultivation experiment was conducted employing artificially simulated seawater of 20 ppt and ambient sea water of 30 ppt to rear juveniles C. semilaevis. Throughout the experiment, the growth performance was assessed and the histology of gonadal development was examined, a significantly lower masculinization rate was observed in LS group. To gain further insights, transcriptome analysis was conducted using raw reads obtained from 53 libraries derived from gonads of 55 days post fertilization (dpf) and 100 dpf juveniles in both LS and CT groups. GO/KEGG enrichment were further proceeded, Terms and pathways involved in reproduction ability, germ cell proliferation, immune function, steroid metabolism etc., were illuminated and a possible crosstalk between HPI and HPG axis was proposed. WGCNA was conducted and two hub genes, hspb8-like and Histone H2A.V were exhibited to be of great significance in the changes of masculinization rate. Our findings provided solid reference for sex differentiation study of GSD + ESD species in a constantly changing ocean environment, as well as practice guiding significance for the environmental management for the culture of C. semilaevis.

Special Issue "Advances in Molecular Pathogenesis and Targeted Therapies for Myeloid Neoplasms"

Myeloid neoplasms (MNs) constitute a diverse group of haematological malignancies that includes myelodysplastic neoplasms (MDS), myeloproliferative neoplasms (MPN), MDS/MPN overlap syndrome, and acute myeloid leukaemia (AML) [...].

Efficacy of novel agents against cellular models of familial platelet disorder with myeloid malignancy (FPD-MM)

Germline, mono-allelic mutations in RUNX1 cause familial platelet disorder (RUNX1-FPD) that evolves into myeloid malignancy (FPD-MM): MDS or AML. FPD-MM commonly harbors co-mutations in the second RUNX1 allele and/or other epigenetic regulators. Here we utilized patient-derived (PD) FPD-MM cells and established the first FPD-MM AML cell line (GMR-AML1). GMR-AML1 cells exhibited active super-enhancers of MYB, MYC, BCL2 and CDK6, augmented expressions of c-Myc, c-Myb, EVI1 and PLK1 and surface markers of AML stem cells. In longitudinally studied bone marrow cells from a patient at FPD-MM vs RUNX1-FPD state, we confirmed increased chromatin accessibility and mRNA expressions of MYB, MECOM and BCL2 in FPD-MM cells. GMR-AML1 and PD FPD-MM cells were sensitive to homoharringtonine (HHT or omacetaxine) or mebendazole-induced lethality, associated with repression of c-Myc, EVI1, PLK1, CDK6 and MCL1. Co-treatment with MB and the PLK1 inhibitor volasertib exerted synergistic in vitro lethality in GMR-AML1 cells. In luciferase-expressing GMR-AML1 xenograft model, MB, omacetaxine or volasertib monotherapy, or co-treatment with MB and volasertib, significantly reduced AML burden and improved survival in the immune-depleted mice. These findings highlight the molecular features of FPD-MM progression and demonstrate HHT, MB and/or volasertib as effective agents against cellular models of FPD-MM.

Myelodysplastic neoplasms evolving from inherited bone marrow failure syndromes / germline predisposition syndromes: Back under the microscope

Inherited bone marrow failure syndromes and germline predisposition syndromes (IBMFS/GPS) are associated with increased risk for hematologic malignancies, particularly myeloid neoplasms, such as myelodysplastic neoplasms (MDS) and acute myeloid leukemia (AML). The diagnosis of MDS in these syndromes poses difficulty due to frequent bone marrow hypocellularity and the presence of some degree of dysplastic features related to the underlying germline defect causing abnormal maturation of one or more cell lines. Yet, the diagnosis of MDS is usually associated with a worse outcome in several IBMFS/GPS. Criteria for the diagnosis of MDS in IBMFS/GPS have not been standardized with some authors suggesting a mixture of morphologic, cytogenetic, and genetic criteria. This review highlights these challenges and suggests a more standardized approach to nomenclature and diagnostic criteria.

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.

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.

Hereditary platelet disorders associated with germ line variants in RUNX1, ETV6, and ANKRD26

Hereditary platelet disorders (HPDs) are a group of blood disorders with variable severity and clinical impact. Although phenotypically there is much overlap, known genetic causes are many, prompting the curation of multigene panels for clinical use, which are being deployed in increasingly large-scale populations to uncover missing heritability more efficiently. For some of these disorders, in particular RUNX1, ETV6, and ANKRD26, pathogenic germ line variants in these genes also come with a risk of developing hematological malignancy (HM). Although they may initially present as similarly mild-moderate thrombocytopenia, each of these 3 disorders have distinct penetrance of HM and a different range of somatic alterations associated with malignancy development. As our ability to diagnose HPDs has improved, we are now faced with the challenges of integrating these advances into routine clinical practice for patients and how to optimize management and surveillance of patients and carriers who have not developed malignancy. The volume of genetic information now being generated has created new challenges in how to accurately assess and report identified variants. The answers to all these questions involve international initiatives on rare diseases to better understand the biology of these disorders and design appropriate models and therapies for preclinical testing and clinical trials. Partnered with this are continued technological developments, including the rapid sharing of genetic variant information and automated integration with variant classification relevant data, such as high-throughput functional data. Collective progress in this area will drive timely diagnosis and, in time, leukemia preventive therapeutic interventions.