Expanding the understanding of telomere biology disorder with reports from two families harboring variants in ZCCHC8 and TERC.

Telomere biology disorder (TBD) can present within a wide spectrum of symptoms ranging from severe congenital malformations to isolated organ dysfunction in adulthood. Diagnosing TBD can be challenging given the substantial variation in symptoms and age of onset across generations. In this report, we present two families, one with a pathogenic variant in ZCCHC8 and another with a novel variant in TERC. In the literature, only one family has previously been reported with a ZCCHC8 variant and TBD symptoms. This family had multiple occurrences of pulmonary fibrosis and one case of bone marrow failure. In this paper, we present a second family with the same ZCCHC8 variant (p.Pro186Leu) and symptoms of TBD including pulmonary fibrosis, hematological disease, and elevated liver enzymes. The suspicion of TBD was confirmed with the measurement of short telomeres in the proband. In another family, we report a novel likely pathogenic variant in TERC. Our comprehensive description encompasses hematological manifestations, as well as pulmonary and hepatic fibrosis. Notably, there are no other reports which associate this variant to disease. The families expand our understanding of the clinical implications and genetic causes of TBD.

Chromothripsis in myeloid malignancies.

Chromothripsis refers to massive genomic rearrangements developed during a catastrophic event. In total acute myeloid leukemia (AML), the incidence of chromothripsis ranges from 0 to 6.6%, in cases of complex karyotype AML, the incidence of chromothripsis ranges from 27.3 to 100%, whereas in cases of AML with TP53 mutations, the incidence ranges from 11.1 to 90%. For other types of malignancies, the incidence of chromothripsis also varies, from 0 to 10.5% in myelodysplastic syndrome to up to 61.5% in cases of myelodysplastic syndrome with TP53 mutations.Chromothripsis is typically associated with complex karyotypes and TP53 mutations, and monosomal karyotypes are associated with the condition. ERG amplifications are frequently noted in cases of chromothripsis, whereas MYC amplifications are not. Moreover, FLT3 and NPM1 mutations are negatively associated with chromothripsis. Chromothripsis typically occurs in older patients with AML with low leukocyte counts and bone marrow blast counts. Rare cases of patients with chromothripsis who received intensive induction chemotherapy revealed low response rates and poor overall prognosis. Signal pathways in chromothripsis typically involve copy number gain and upregulation of oncogene gene sets that promote cancer growth and a concomitant copy number loss and downregulation of gene sets associated with tumor suppression functions.Patients with chromothripsis showed a trend of lower complete remission rate and worse overall survival in myeloid malignancy. Large-scale studies are required to further elucidate the causes and treatments of the condition.

Precision medicine in myeloid malignancies.

Myeloid malignancies have always been at the forefront of an improved understanding of the molecular pathogenesis of cancer. In accordance, over the last years, basic research focusing on the aberrations underlying malignant transformation of myeloid cells has provided the basis for precision medicine approaches and subsequently has led to the development of powerful therapeutic strategies. In this review article, we will recapitulate what has happened since in the 1980s the use of all-trans retinoic acid (ATRA), as a first targeted cancer therapy, has changed one of the deadliest leukemia subtypes, acute promyelocytic leukemia (APL), into one that can be cured without classical chemotherapy today. Similarly, imatinib, the first molecularly designed cancer therapy, has revolutionized the management of chronic myeloid leukemia (CML). Thus, targeted treatment approaches have become the paradigm for myeloid malignancy, but many questions still remain unanswered, especially how identical mutations can be associated with different phenotypes. This might be linked to the impact of the cell of origin, gene-gene interactions, or the tumor microenvironment including the immune system. Continuous research in the field of myeloid neoplasia has started to unravel the molecular pathways that are not only crucial for initial treatment response, but also resistance of leukemia cells under therapy. Ongoing studies focusing on leukemia cell vulnerabilities do already point to novel (targetable) "Achilles heels" that can further improve myeloid cancer therapy.

Incidence and Bayesian Mapping of Myeloid Hematologic Malignancies in Sardinia, Italy.

BACKGROUND: The epidemiology of myeloid hematologic malignancies in Italy has been poorly investigated. METHODS: We used a validated database of 1974-2003 incident cases of hematologic malignancies among the resident population (all ages) of Sardinia, Italy, to describe the incidence of myeloid malignancies overall (N = 4389 cases) and by subtype. We investigated the time trend of acute myeloid leukemia (N = 1227 cases), chronic myeloid leukemia (N = 613 cases), and myelodysplastic syndrome (N = 1296 cases), and used Bayesian methods to explore their geographic spread, and Poisson regression analysis to estimate their association with environmental and socio-economic factors. RESULTS: The annual standardized (world population) incidence rate (IR) of myeloid malignancies over the study period was 6.5 per 100,000 (95% CI 6.2-6.7). Myelodysplastic syndromes were the most prevalent subgroup (IR = 1.7, 95% CI 1.5-1.8). Incidence of all myeloid malignancies combined increased sharply during the study period with an annual percent change (APC) of 10.06% (95% CI 9.51-10.61), 19.77% for myelodysplastic syndromes (95% CI 19.63-19.91), and 3.18% (95% CI 2.99-3.37) for acute myeloid leukemia. Chronic myeloid leukemia did not show an upward trend. Apart from sporadic excesses in small rural communities and the major urban area, there was no evidence of spatial clustering. The risk of myeloid malignancies increased with increasing prevalence of sheep breeding. CONCLUSIONS: Our results might prompt further research on the local genetic and environmental determinants of myeloid hematologic malignancies.

Erdheim-Chester Disease with BRAF V600E Mutation and a Concomitant Myeloid Malignancy Sharing NRAS and IDH2 Mutations.

Erdheim-Chester disease (ECD) is a rare clonal histiocytic process that is characterized by a foamy (xanthomatous) proliferation often associated with Touton giant cells. The diagnosis is often challenging and not exclusively a histologic diagnosis, as it requires correlation with unique clinical, radiographic, and recently described molecular findings. Activating mutations involving the MAPK pathway including BRAF, ARAF, N/KRAS, and MEK are recurrent in the disease. However, it is increasingly being described that mutations associated with clonal hematopoiesis are also found in bone marrow specimens of patients with ECD, as well as higher frequency of overt concomitant myeloid malignancy including acute myeloid leukemia, myeloproliferative neoplasms, myelodysplastic syndromes, and mixed myeloproliferative neoplasms/myelodysplastic syndromes. Herein, we report a unique case of a patient presenting with BRAFV600E-positive ECD with peripheral blood findings consistent with a concurrent myeloid malignancy featuring co-occurrence of NRAS and IDH2 mutations.

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.

Disease-related thrombocytopenia in myelofibrosis is defined by distinct genetic etiologies and is associated with unique prognostic correlates.

BACKGROUND: Thrombocytopenia in patients with myelofibrosis (MF) is prognostically detrimental and poses a therapeutic challenge. MF patients with thrombocytopenia are considered high-risk by most prognostic models and their distinct phenotype has given rise to the emerging concept of cytopenic MF. Yet, the mechanisms underlying thrombocytopenia in MF are poorly understood. METHODS: This study aimed to highlight the genetic mechanisms driving low platelet counts in treatment-naive MF patients, establish their phenotypic correlates, and assess prognostic factors specific to this group of patients. RESULTS: The authors found that most patients presenting with low platelets had a clear thrombocytopenia-specific genetic abnormality involving a U2AF1 Q157 mutation, deletion 20q, molecular complexity (three or more mutations), or high-risk karyotype. Etiologic clustering did not correlate with prognosis; however, thrombocytopenic patients were found to have unique prognostic variables including low serum albumin and mutations of SRSF2 and TP53. This led to the proposal of a prognostic model (SRSF2, albumin, TP53 score) that stratifies thrombocytopenic patients as low, intermediate, or high-risk with corresponding median survivals of 93.5, 29.5, and 7.2 months, respectively. CONCLUSIONS: This study demonstrates that thrombocytopenia in MF is driven by different genetic mechanisms and is not uniformly high-risk. As novel agents with improved hematologic safety profiles enter the treatment landscape, thoughtful, risk-adapted therapeutic decisions will be required for MF patients with thrombocytopenia. LAY SUMMARY: A significant minority of patients with myelofibrosis (MF) present with low platelets. Historically, these patients have been viewed as having "high-risk" disease, but this may not be uniformly true. Our study shows that there are various different causes for low platelets in MF, some of which represent high-risk disease whereas others do not. Additionally, our study shows that genetic mutations affecting the genes SRSF2 and TP53 are uniquely problematic in this group, as is a low serum albumin level. This study helps to risk-stratify MF patients with thrombocytopenia, thereby providing more information to guide informed and individualized treatment decisions.

Signaling pathways, microenvironment, and targeted treatments in Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid malignancy in the "L-group" histiocytosis. Mitogen-activated protein kinase (MAPK) pathway activating mutations are detectable in nearly all LCH lesions. However, the pathogenic roles of MAPK pathway activation in the development of histiocytosis are still elusive. This review will summarize research concerning the landscape and pathogenic roles of MAPK pathway mutations and related treatment opportunities in Langerhans cell histiocytosis. Video abstract.

GATA2 deficiency syndrome: A decade of discovery.

GATA2 deficiency syndrome (G2DS) is a rare autosomal dominant genetic disease predisposing to a range of symptoms, of which myeloid malignancy and immunodeficiency including recurrent infections are most common. In the last decade since it was first reported, there have been over 480 individuals identified carrying a pathogenic or likely pathogenic germline GATA2 variant with symptoms of G2DS, with 240 of these confirmed to be familial and 24 de novo. For those that develop myeloid malignancy (75% of all carriers with G2DS disease symptoms), the median age of onset is 17 years (range 0-78 years) and myelodysplastic syndrome is the first diagnosis in 75% of these cases with acute myeloid leukemia in a further 9%. All variant types appear to predispose to myeloid malignancy and immunodeficiency. Apart from lymphedema in which haploinsufficiency seems necessary, the mutational requirements of the other less common G2DS phenotypes is still unclear. These predominantly loss-of-function variants impact GATA2 expression and function in numerous ways including perturbations to DNA binding, protein structure, protein:protein interactions, and gene transcription, splicing, and expression. In this review, we provide the first expert-curated ACMG/AMP classification with codes of published variants compatible for use in clinical or diagnostic settings.

GATA2 mutations in myeloid malignancies: Two zinc fingers in many pies.

The GATA family of transcription factors are zinc finger (ZF) DNA-binding proteins that regulate transcription during development and cell differentiation. GATA2 plays an essential role in the regulation of hematopoiesis. As a result, mutations in this gene or alterations in its expression level or function have been linked to a variety of human hematologic disorders. In this review, we summarize the findings and developments over the recent years regarding the clinical correlations and functional properties of distinct GATA2 mutations in hematopoietic malignancies, with particular focus on the mutational hotspots in the ZF domains.

LEF1-AS1, long non-coding RNA, inhibits proliferation in myeloid malignancy.

LEF1 antisense RNA 1 (LEF1-AS1) is an antisense long non-coding RNA encoded in the lymphoid enhancer-binding factor 1 (LEF1) locus. LEF1-AS1 is a conserved transcript dysregulated in hematopoiesis. This study aimed to functionally characterize the role of this transcript in myeloid malignancy and explore a possible regulatory effect of LEF1-AS1 upon LEF1. We show that LEF1-AS1 is highly expressed in normal hematopoietic stem cells but barely detectable in myeloid malignant cell lines. Additionally, bone marrow cells from myelodysplastic syndrome (n=12) and acute myeloid malignancy patients (n=28) expressed significantly reduced levels of LEF1-AS1 compared to healthy controls (n=15). Artificial LEF1-AS1 over-expression inhibited proliferation in HL60 and led to an upregulation of tumor suppressors p21 and p27, and reduced ERK1/2 activation. Unexpectedly, no underlying modulation of LEF1 was detected. Ectopic expression of LEF1-AS1 also inhibited proliferation in HELA, a cell line lacking endogenous expression of LEF1, supporting a LEF1-independent mechanism. Additionally, transient over-expression of LEF1-AS1 in AML patient cells also led to reduced proliferation and colony formation capacity. We used a mass spectrometry-based proteomics approach. Proteomic quantification identified the modulation of an important metabolic regulator, Fumarase, and concomitant accumulation of the metabolite fumarate.

Impact of Obesity on Clinical Outcomes of Elderly Patients Undergoing Allogeneic Hematopoietic Cell Transplantation for Myeloid Malignancies.

Allogeneic hematopoietic cell transplantation (allo-HCT) is a high-risk treatment option for patients with hematologic malignancies. Advanced age and obesity can impact outcomes after allo-HCT. Previous registry studies of all age groups found that obesity does not affect outcomes. However, obesity can accelerate age-related decline in physical function and exacerbate comorbid conditions in older patients. Studies evaluating the effect of obesity on elderly patients undergoing allo-HCT are lacking. We performed a retrospective analysis of 86 nonobese (body mass index [BMI] <30) and obese (BMI ≥30) patients age ≥60 years who underwent allo-HCT for myeloid malignancies between January 2010 and June 2015. We found no significant between-group differences in mean age, sex, comorbid conditions, cytogenetic risk, disease indication for transplantation, or donor type. The median overall survival (OS) was 36 months for the BMI <30 group and 24 months for the BMI ≥30 group (P = .55). The median progression-free survival (PFS) was 10.1 months in the BMI <30 group and 13.6 months in the BMI ≥30 group (P = .93). There were no significant between-group differences in acute graft-versus-host disease (GVHD) and cumulative incidence of chronic GVHD at 1 year post-transplantation. Among patients admitted for transplantation, the mean length of stay was 25 days in the BMI <30 group and 26 days in the BMI ≥30 group (P = .64). The rate of readmission within 30 days of discharge was significantly higher in the BMI ≥30 group (34% versus 16%; P = .045). Our data reveal that in these elderly patients with myeloid malignancies undergoing allo-HCT, clinical outcomes, including OS, PFS, and GVHD, were not affected by obesity. Thus, in elderly patients, obesity should not preclude consideration for curative allo-HCT and does not portend worse outcomes after allo-HCT.

Fludarabine and busulfan plus low-dose TBI as reduced intensity conditioning in older patients undergoing allogeneic hematopoietic cell transplant for myeloid malignancies.

We have been using a combination of fludarabine/busulfan plus low-dose total body irradiation (TBI) as the reduced-intensity conditioning (RIC) regimen for patients age ≥ 60 years undergoing allogeneic hematopoietic cell transplantation (HCT) for myeloid malignancies. We retrospectively analyzed outcomes of 116 older patients (median age 64 years) who underwent HCT from 2006 to 2015 for myeloid malignancies, including acute myeloid leukemia (AML) in first complete remission (CR1). On univariate analysis, overall survival (OS) for the cohort at 3 years was 33% (95% CI 25-42). Cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) at 3 years were 24% (95% CI 16-32) and 43% (95% CI 34-52), respectively. Multivariable analysis for OS demonstrated AML patients to have superior outcome (HR 1.60 for other myeloid, 95% CI 1.01-2.54, p = 0.045), as well as related donors (HR 1.92 for unrelated, 95% CI 1.22-3.03, p = 0.005). For NRM, AML patients had superior outcome (HR 1.76 for other myeloid, 95% CI 1.03-3.01, p = 0.038), as well as patients with related donors (HR 1.81 for unrelated, 95% CI 1.07-3.07, p = 0.028). We then demonstrated that AML patients with related donors (n = 45) had superior 3-year OS of 51% (95% CI 36-65), compared to 21% (95% CI 12-32) for all other patients (p = 0.0003). We conclude that the RIC regimen used is effective for older patients, particularly AML patients in CR1 with matched related donors.

Cohesin mutations in human cancer.

Cohesin is a highly-conserved protein complex that plays important roles in sister chromatid cohesion, chromatin structure, gene expression, and DNA repair. In humans, cohesin is a ubiquitously expressed, multi-subunit protein complex composed of core subunits SMC1A, SMC3, RAD21, STAG1/2 and regulatory subunits WAPL, PDS5A/B, CDCA5, NIPBL, and MAU2. Recent studies have demonstrated that genes encoding cohesin subunits are somatically mutated in a wide range of human cancers. STAG2 is the most commonly mutated subunit, and in a recent analysis was identified as one of only 12 genes that are significantly mutated in four or more cancer types. In this review we summarize the findings reported to date and comment on potential functional implications of cohesin mutation in the pathogenesis of human cancer.

Clinical Utility of Wilms' Tumor 1 Monitoring in Patients with Myeloid Malignancy and Prior Allogeneic Hematopoietic Stem Cell Transplantation.

Although allogeneic hematopoietic stem cell transplantation (allo-HSCT) is 1 of the standard treatments for myeloid malignancy, relapse remains a major obstacle to cure. Early detection of relapse by monitoring of minimal residual disease (MRD) may enable us to intervene pre-emptively and potentially prevent overt relapse. Wilms' tumor 1 (WT1) is well known as a pan-leukemic marker. We retrospectively examined serially monitored WT1 levels of peripheral blood in 98 patients (84 with acute myeloid leukemia and 14 with myelodysplastic syndrome). At the time of allo-HSCT, 49 patients (50%) were in complete remission. Patients were divided into 3 groups according to WT1 levels (<50 copies/µg RNA, 50 to 500 copies/µg RNA and >500 copies/µg RNA). The cumulative incidence of relapse (CIR) and overall survival (OS) differed statistically according to the WT1 levels before allo-HSCT and at days 30 and 60 after allo-HSCT. In multivariate analysis, WT1 >500 copies/µg RNA before and at day 60 after allo-HSCT and WT1 ≥50 copies/µg RNA at day 30 were correlated with CIR. Moreover, WT1 >500 copies/µg RNA at day 60 after allo-HSCT was only correlated with worse OS. Our data suggest that serial monitoring of WT1 levels in peripheral blood may be useful for MRD monitoring and as a predictor of hematological relapse in allo-HSCT.

Programmed cell death-1 pathway inhibition in myeloid malignancies: implications for myeloproliferative neoplasms.

Myeloproliferative neoplasms (MPNs) are clonal hematopoietic diseases that belong to the spectrum of myeloid malignancies (MyMs), which also include myelodysplastic syndromes (MDS), acute myeloid leukemia (AML), and chronic myelogenous leukemia (CML). While hematopoietic stem cell transplantation (HSCT) is a potentially curative therapeutic approach to many MyMs, the associated morbidity and mortality have necessitated the development of non-HSCT therapeutics for symptom management and disease course modification. Immune checkpoint inhibition, in particular along the programmed cell death protein 1 (PD-1)/B7-H1 (PD-L1) axis, is an established strategy in solid tumors with potential as an adjunctive therapy in hematologic malignancies. Seminal studies suggest that the pro-inflammatory microenvironment of MyMs can suppress T lymphocyte-mediated immunity via PD-1 signaling and that response to mainstay epigenetic therapies for MyMs may be governed by PD-1 gene regulation. Although the role of PD-1 signaling in MPN pathogenesis and progression is as yet unclear, research in MPN patients has revealed expansion of myeloid-derived suppressor cells (MDSCs), which may effect host immune tolerance of tumor via temporally and spatially specific activation of PD-1/PD-L1 signaling. The current understanding of immune dysfunction in MPNs and analogous MyMs offers a compelling rationale to study PD-1/PD-L1 inhibition in patients as a novel treatment option.

Whole-exome sequencing enhances prognostic classification of myeloid malignancies.

PURPOSE: To date the standard nosology and prognostic schemes for myeloid neoplasms have been based on morphologic and cytogenetic criteria. We sought to test the hypothesis that a comprehensive, unbiased analysis of somatic mutations may allow for an improved classification of these diseases to predict outcome (overall survival). EXPERIMENTAL DESIGN: We performed whole-exome sequencing (WES) of 274 myeloid neoplasms, including myelodysplastic syndrome (MDS, N=75), myelodysplastic/myeloproliferative neoplasia (MDS/MPN, N=33), and acute myeloid leukemia (AML, N=22), augmenting the resulting mutational data with public WES results from AML (N=144). We fit random survival forests (RSFs) to the patient survival and clinical/cytogenetic data, with and without gene mutation information, to build prognostic classifiers. A targeted sequencing assay was used to sequence predictor genes in an independent cohort of 507 patients, whose accompanying data were used to evaluate performance of the risk classifiers. RESULTS: We show that gene mutations modify the impact of standard clinical variables on patient outcome, and therefore their incorporation hones the accuracy of prediction. The mutation-based classification scheme robustly predicted patient outcome in the validation set (log rank P=6.77 × 10(-21); poor prognosis vs. good prognosis categories HR 10.4, 95% CI 3.21-33.6). The RSF-based approach also compares favorably with recently-published efforts to incorporate mutational information for MDS prognosis. CONCLUSION: The results presented here support the inclusion of mutational information in prognostic classification of myeloid malignancies. Our classification scheme is implemented in a publicly available web-based tool (http://myeloid-risk. CASE: edu/).

A Predictive Algorithm for Discriminating Myeloid Malignancies and Leukemoid Reactions.

BACKGROUND: Adults presenting with a neutrophil-predominant leukocytosis (white cell count >50,000/µL) often necessitate urgent medical management. These patients are diagnosed with either acute presentations of chronic myeloid malignancies or leukemoid reactions, yet accurate models to distinguish between these entities do not exist. We used demographic and lab data to build a machine learning model capable of discriminating between these diagnoses. METHODS: The medical record at a tertiary care medical center was queried to identify adults with instances of white counts greater than 50,000/µL and >50% neutrophils from 2000 to 2021. For each patient, a full set of demographic and lab values were extracted at the time of their first presentation with a white count >50,000/µL. We generated a series of models in which the parameters most predictive of myeloid malignancies were identified, and a supervised machine learning approach was applied to the dataset. RESULTS: Our best model-using a support vector machine algorithm-produced a sensitivity of 96% and a specificity of 95.9% (area under the curve = 0.982) for identifying myeloid malignancies. We also identified a clinically meaningful and significant disparity in outcomes based on diagnosis-a 6-fold increase in 12-month mortality in those diagnosed with leukemoid reactions. CONCLUSIONS: These findings need to be validated but fill an unmet need for timely and accurate diagnosis in the setting of profound, neutrophil-predominant leukocytosis and support the use of predictive models as a means to improve patient outcomes.