Familial myelodysplastic syndromes: a review of the literature

P53 IHC Result as a Prognostic Tool in MDS

Background & Objective

Some of the patients with myelodysplastic syndrome (MDS) are categorized as good prognosis based on the Revised International Prognostic Scoring System (IPSS-R). However, these patients may have poor clinical outcomes. It seems that the current diagnostic tools and IPSS-R cannot consider genetic factors for determining the prognosis of MDS patients.

Methods

This cross-sectional study included all adult MDS patients of both genders who were admitted from March 2015 to March 2020 to the Hematology wards of two educational tertiary hospitals in Iran (Namazi and Faghihi, affiliated with Shiraz University of medical sciences). Study data included relevant retrospective data from medical records and the results of immunohistochemical p53 staining on bone marrow biopsies.

Results

Of the 84 patients, 65 (77.4%) showed p53 expression in bone marrow. They had shorter median survival than those without p53 expression. Considering both variables of P53 IHC results and IPSS-R score, the patients who died with low-risk IPSS-R score presented high p53 expression.

Conclusion

This study shows that the investigation of p53 expression by IHC at the time of diagnosis is a valuable indicator of survival rate in MDS patients. These data suggest that the immunohistochemical analysis of p53 can be a prognostic tool for MDS and should be used as an adjunct test to make decisions on the best therapeutic choice.

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.

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.

Molecular Drivers of Myelodysplastic Neoplasms (MDS)-Classification and Prognostic Relevance

Myelodysplastic neoplasms (MDS) form a broad spectrum of clonal myeloid malignancies arising from hematopoietic stem cells that are characterized by progressive and refractory cytopenia and morphological dysplasia. Recent advances in unraveling the underlying pathogenesis of MDS have led to the identification of molecular drivers and secondary genetic events. With the overall goal of classifying patients into relevant disease entities that can aid to predict clinical outcomes and make therapeutic decisions, several MDS classification models (e.g., French-American-British, World Health Organization, and International Consensus Classification) as well as prognostication models (e.g., International Prognostic Scoring system (IPSS), the revised IPSS (IPSS-R), and the molecular IPSS (IPSS-M)), have been developed. The IPSS-M is the first model that incorporates molecular data for individual genes and facilitates better prediction of clinical outcome parameters compared to older versions of this model (i.e., overall survival, disease progression, and leukemia-free survival). Comprehensive classification and accurate risk prediction largely depend on the integration of genetic mutations that drive the disease, which is crucial to improve the diagnostic work-up, guide treatment decision making, and direct novel therapeutic options. In this review, we summarize the most common cytogenetic and genomic drivers of MDS and how they impact MDS prognosis and treatment decisions.

Assessing patient attitudes toward genetic testing for hereditary hematologic malignancy

Since 2003, more than 15 genes have been identified to predispose to hereditary hematologic malignancy (HHM). Although the yield of germline analysis for leukemia appears like that of solid tumors, genetic referrals in adults with leukemia remain underperformed. We assessed leukemia patients' attitudes toward genetic testing and leukemia-related distress through a survey of 1093 patients diagnosed with acute or chronic leukemia, myelodysplastic syndrome, or aplastic anemia. Principal component analysis (PCA) was used to analyze patient attitudes. Distress was measured through the Impact of Event Scale-Revised (IES-R). Exactly 19.8% of eligible respondents completed the survey. The majority reported interest in (77%) or choosing to have (78%) genetic testing for HHM. Slightly over half identified worry about cost of genetic testing (58%) or health insurance coverage (61%) as possible barriers. PCA identified relevant themes of interest in genetic testing, impact on leukemia treatment, discrimination and confidentiality, psychosocial and familial impacts, and cost of testing. The majority reported low distress. Leukemia patients report high interest in genetic testing, few barriers, and relatively low distress.

Clinical utility of targeted next-generation sequencing for the diagnosis of myeloid neoplasms with germline predisposition

Myeloid neoplasms (MN) with germline predisposition (MNGP) are likely to be more common than currently appreciated. Many of the genes involved in MNGP are also recurrently mutated in sporadic MN. Therefore, routine analysis of gene panels by next-generation sequencing provides an effective approach to detect germline variants with clinical significance in patients with hematological malignancies. Gene panel sequencing was performed in 88 consecutive and five nonconsecutive patients with MN diagnosis. Disease-causing germline mutations in CEBPα, ASXL1, TP53, MPL, GATA2, DDX41, and ETV6 genes were identified in nine patients. Six out of the nine patients with germline variants had a strong family history. These patients presented great heterogeneity in the age of diagnosis and phenotypic characteristics. In our study, there were families in which all the affected members presented the same subtype of disease, whereas members of other families presented various disease phenotypes. This intrafamiliar heterogeneity suggests that the acquisition of particular somatic variants may drive the evolution of the disease. This approach enabled high-throughput detection of MNGP in patients with MN diagnosis, which is of great relevance for both the patients themselves and the asymptomatic mutation carriers within the family. It is crucial to make a proper diagnosis of these patients to provide them with the most suitable treatment, follow-up, and genetic counseling.

Myelodysplastic Syndromes: A New Decade

Myelodysplastic syndromes (MDS) are a group of heterogeneous clonal hematopoietic stem cell disorders. The 2020 Surveillance, Epidemiology, and End Results data demonstrates the incidence rate of MDS increases with age especially in those greater than 70 years of age. Risk stratification that impact prognosis, survival, and rate of acute myeloid leukemia (AML) transformation in MDS is largely dependent on revised International Prognostic Scoring System along with molecular genetic testing as a supplement. Low risk MDS typically have a more indolent disease course in which treatment is only initiated to ameliorate symptoms of cytopenias. In many, anemia is the most common cytopenia requiring treatment and erythroid stimulating agents, are considered first line. In contrast, high risk MDS tend to behave more aggressively for which treatment should be initiated rapidly with Hypomethylating Agents (HMA) being in the frontline. In those with high risk MDS and eligible, evaluation for allogeneic stem cell transplant should be considered as this is the only potential curative option for MDS. With the use of molecular genetic testing, a personalized approach to therapy in MDS has ensued. As the treatment landscape in MDS continues to flourish with novel targeted agents, we ambitiously seek to improve survival rates especially among the relapsed/refractory and transplant ineligible.

[Familial platelet disorder with predisposition to myeloid leukemia (FPD/AML): a case report and literature review]

目的

探讨RUNX1胚系突变导致的家族性血小板疾病并急性髓系白血病倾向（FPD/AML）患儿及其家族成员的临床特点及基因突变情况。

方法

对2019年10月中国医学科学院血液病医院儿童血液诊疗中心收治的1例FPD/AML患儿及部分家族成员的临床资料及基因突变结果进行分析。并以“RUNX1胚系突变”“家族性血小板疾病并急性髓系白血病倾向”“RUNX1 germline mutation”“FPD/AML”为检索词，检索建库至2020年9月中文数据库（中国知网数据库、万方数据库及维普数据库）及PubMed数据库进行文献复习。

结果

患儿为5岁男孩，因发现血小板减少3年入院。体格检查提示存在皮肤出血点，其他无明显异常。辅助检查：外周血常规示WBC 6.38×10⁹/L，HGB 113 g/L，PLT 54×10⁹/L，中性粒细胞绝对计数4.03×10⁹/L，血小板平均体积（MPV）9.1 fl。骨髓涂片提示巨核系发育异常。涂片免疫CD42b及CD41酶标提示存在小巨核细胞。基因检测提示RUNX1（exon3: c.520delC:p.R174Efs*10, NM_001001890）的移码突变，经口腔上皮细胞验证为胚系突变。家族史中共有5名家族成员存在血液系统疾病并相继死亡。患儿母亲及外祖父先后进行了与血液肿瘤疾病相关的137个基因热点区域的基因检测，均检测到与患儿相同位点的RUNX1移码突变，但是三人的临床症状十分不同。文献检索共检索到相关英文文献37篇，报道了70多个FPD/AML家族，未检索到相关中文文献。

结论

RUNX1胚系突变是导致FPD/AML的病因，进展为髓系恶性肿瘤的风险极高，携带相同突变的家族成员可能表现出非常不同的临床症状和严重程度。

A novel RUNX1 exon 3 - 7 deletion causing a familial platelet disorder

Familial Platelet Disorder with associated Myeloid Malignancy (FPDMM) is a rare inherited disorder confirmed with the presence of a pathogenic germline RUNX1 variant and is thought to be heavily underdiagnosed. RUNX1 has also been found to be mutated in up to 10% of adult AML cases and other cell malignancies. We performed targeted next-generation sequencing and subsequent MLPA analysis in a kindred with multiple affected individuals with low platelet counts and a bleeding history. We detected a novel heterozygous exon 3-7 large deletion in the RUNX1 gene in all affected family members which is predicted to remove all of the Runt-homology DNA-binding domain and a portion of the Activation domain. Our results show that the combination of targeted NGS and MLPA analysis is an effective way to detect copy number variants (CNVs) which would be missed by conventional sequencing methods. This precise diagnosis offers the possibility of accurate counseling and clinical management in such patients who could go onto develop other cell malignancies.

Inherited thrombocytopenias: an updated guide for clinicians

The great advances in the knowledge of inherited thrombocytopenias (ITs) made since the turn of the century have significantly changed our view of these conditions. To date, ITs encompass 45 disorders with different degrees of complexity of the clinical picture and very wide variability in the prognosis. They include forms characterized by thrombocytopenia alone, forms that present with other congenital defects, and conditions that predispose to acquire additional diseases over the course of life. In this review, we recapitulate the clinical features of ITs with emphasis on the forms predisposing to additional diseases. We then discuss the key issues for a rational approach to the diagnosis of ITs in clinical practice. Finally, we aim to provide an updated and comprehensive guide to the treatment of ITs, including the management of hemostatic challenges, the treatment of severe forms, and the approach to the manifestations that add to thrombocytopenia.

Genetic predisposition in pediatric oncology

Identifying patients with a genetic predisposition for developing malignant tumors has a significant impact on both the patient and family. Recognition of genetic predisposition, before diagnosing a malignant pathology, may lead to early diagnosis of a neoplasia. Recognition of a genetic predisposition syndrome after the diagnosis of neoplasia can result in a change of treatment plan, a specific follow-up of adverse treatment effects and, of course, a long-term follow-up focusing on the early detection of a second neoplasia.

Responsible for genetic syndromes that predispose individuals to malignant pathology are germline mutations. These mutations are present in all cells of conception, they can be inherited or can occur de novo.

Several mechanisms of inheritance are described: Mendelian autosomal dominant, Mendelian autosomal recessive, X-linked patterns, constitutional chromosomal abnormality and non-Mendelian inheritance.

In the following review we will present the most important genetic syndromes in pediatric oncology.

Secondary leukemia in patients with germline transcription factor mutations (RUNX1, GATA2, CEBPA)

Recognition that germline mutations can predispose individuals to blood cancers, often presenting as secondary leukemias, has largely been driven in the last 20 years by studies of families with inherited mutations in the myeloid transcription factors (TFs) RUNX1, GATA2, and CEBPA. As a result, in 2016, classification of myeloid neoplasms with germline predisposition for each of these and other genes was added to the World Health Organization guidelines. The incidence of germline mutation carriers in the general population or in various clinically presenting patient groups remains poorly defined for reasons including that somatic mutations in these genes are common in blood cancers, and our ability to distinguish germline (inherited or de novo) and somatic mutations is often limited by the laboratory analyses. Knowledge of the regulation of these TFs and their mutant alleles, their interaction with other genes and proteins and the environment, and how these alter the clinical presentation of patients and their leukemias is also incomplete. Outstanding questions that remain for patients with these germline mutations or their treating clinicians include: What is the natural course of the disease? What other symptoms may I develop and when? Can you predict them? Can I prevent them? and What is the best treatment? The resolution of many of the remaining clinical and biological questions and effective evidence-based treatment of patients with these inherited mutations will depend on worldwide partnerships among patients, clinicians, diagnosticians, and researchers to aggregate sufficient longitudinal clinical and laboratory data and integrate these data with model systems.

Epigenetic Research in Stem Cell Bioengineering-Anti-Cancer Therapy, Regenerative and Reconstructive Medicine in Human Clinical Trials

The epigenome denotes all the information related to gene expression that is not contained in the DNA sequence but rather results from chemical changes to histones and DNA. Epigenetic modifications act in a cooperative way towards the regulation of gene expression, working at the transcriptional or post-transcriptional level, and play a key role in the determination of phenotypic variations in cells containing the same genotype. Epigenetic modifications are important considerations in relation to anti-cancer therapy and regenerative/reconstructive medicine. Moreover, a range of clinical trials have been performed, exploiting the potential of epigenetics in stem cell engineering towards application in disease treatments and diagnostics. Epigenetic studies will most likely be the basis of future cancer therapies, as epigenetic modifications play major roles in tumour formation, malignancy and metastasis. In fact, a large number of currently designed or tested clinical approaches, based on compounds regulating epigenetic pathways in various types of tumours, employ these mechanisms in stem cell bioengineering.

Nationwide epidemiological survey of familial myelodysplastic syndromes/acute myeloid leukemia in Japan: a multicenter retrospective study

Although several pedigrees of familial myelodysplastic syndromes/acute myeloid leukemia (fMDS/AML) have been reported, the epidemiology and clinical features has been poorly understood. To explore the epidemiology of this entity, we performed a retrospective nationwide epidemiological survey in Japan using questionnaire sheets. The questionnaire was sent to 561 institutions or hospitals certified by Japanese Society of Hematology, unearthing the existence of 41 pedigrees of fMDS/AML. Among them, we obtained the clinical information of 31 patients in 20 pedigrees. The median age of the initial diagnosis was 51 years (range 9-88 years) and the WHO classification 2008 ranged from refractory anemia (RA) to AML. Focusing on the familial MDS patients, refractory anemia with excess blasts (RAEB)-2 was the largest group (27.3%). The median overall survival (OS) of fMDS and fAML in this study were 71.6 and 12.4 months, and the five-year OS were 61.3 and 50%, respectively.

How I curate: applying American Society of Hematology-Clinical Genome Resource Myeloid Malignancy Variant Curation Expert Panel rules for RUNX1 variant curation for germline predisposition to myeloid malignancies

The broad use of next-generation sequencing and microarray platforms in research and clinical laboratories has led to an increasing appreciation of the role of germline mutations in genes involved in hematopoiesis and lineage differentiation that contribute to myeloid neoplasms. Despite implementation of the American College of Medical Genetics and Genomics and Association for Molecular Pathology 2015 guidelines for sequence variant interpretation, the number of variants deposited in ClinVar, a genomic repository of genotype and phenotype data, and classified as having uncertain significance or being discordantly classified among clinical laboratories remains elevated and contributes to indeterminate or inconsistent patient care. In 2018, the American Society of Hematology and the Clinical Genome Resource co-sponsored the Myeloid Malignancy Variant Curation Expert Panel to develop rules for classifying gene variants associated with germline predisposition to myeloid neoplasia. Herein, we demonstrate application of our rules developed for the RUNX1 gene to variants in six examples to show how we would classify them within the proposed framework.

ETV6: A Candidate Gene for Predisposition to "Blend Pedigrees"? A Case Report from the NEXT-Famly Clinical Trial

Background

The identification of germline mutations in familial leukemia predisposition genes by next generation sequencing is of pivotal importance. Lately, some “blend pedigrees” characterized by both solid and hematologic malignancies have been described. Some genes were recognized as related to this double predisposition, while the involvement of others is still a matter of debate. ETV6 was associated with hematologic malignancies, in particular myeloid malignancies, and recently described as mutated also in oncologic patients. No clear evidences in its involvement in blend pedigrees are known. Case Presentation. We present our recent experience in the identification of an ETV6 was associated with hematologic malignancies, in particular myeloid malignancies, and recently described as mutated also in oncologic patients. No clear evidences in its involvement in blend pedigrees are known. ETV6 was associated with hematologic malignancies, in particular myeloid malignancies, and recently described as mutated also in oncologic patients. No clear evidences in its involvement in blend pedigrees are known. ETV6 was associated with hematologic malignancies, in particular myeloid malignancies, and recently described as mutated also in oncologic patients. No clear evidences in its involvement in blend pedigrees are known.

Conclusion

This evidence supports the involvement of ETV6 in the predisposition to both solid and hematologic neoplasia and the importance of the investigation of the noncoding regions of the genes as recently suggested by different expert groups.ETV6 was associated with hematologic malignancies, in particular myeloid malignancies, and recently described as mutated also in oncologic patients. No clear evidences in its involvement in blend pedigrees are known.

RUNX1 mutations enhance self-renewal and block granulocytic differentiation in human in vitro models and primary AMLs

To unravel molecular mechanisms by which Runt-related transcription factor 1 (RUNX1) mutations contribute to leukemic transformation, we introduced the RUNX1-S291fs300X mutation in human CD34⁺ stem/progenitor cells and in human induced pluripotent stem cells (iPSCs). In both models, RUNX1mut overexpression strongly impaired myeloid commitment. Instead, self-renewal was enhanced, as shown, by increased long-term culture-initiating cell frequencies and enhanced colony-forming cell replating capacity. Long-term suspension cultures with RUNX1mut-transduced cord blood (CB) CD34⁺ cells continued for more than 100 days, during which the cells displayed an immature granulocyte-macrophage progenitor-like CD34⁺/CD123⁺/CD45RA⁺ phenotype. The CD34⁺/CD38^- hematopoietic stem cell (HSC) population most likely acted as cell of origin, as HSCs provided the best long-term proliferative potential on overexpression of RUNX1mut. CEBPA expression was reduced in RUNX1mut cells, and reexpression of CEBPA partly restored differentiation. RNA-seq analysis on CB/iPSC systems and on primary patient samples confirmed that RUNX1 mutations induce a myeloid differentiation block, and that a common set of RUNX1mut-upregulated target genes was strongly enriched for gene ontology terms associated with nucleosome assembly and chromatin structure. Interestingly, in comparison with AML1-ETO binding in acute myeloid leukemias (AMLs), we found significantly distinct genomic distribution and differential expression for RUNX1mut of genes such as TCF4, MEIS1, and HMGA2 that may potentially contribute to the underlying difference in clinical outcomes between RUNX1mut and AML1-ETO patients. In conclusion, RUNX1mut appears to induce a specific transcriptional program that contributes to leukemic transformation.

Nordic Guidelines for Germline Predisposition to Myeloid Neoplasms in Adults: Recommendations for Genetic Diagnosis, Clinical Management and Follow-up

Myeloid neoplasms (MNs) with germline predisposition have recently been recognized as novel entities in the latest World Health Organization (WHO) classification for MNs. Individuals with MNs due to germline predisposition exhibit increased risk for the development of MNs, mainly acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Setting the diagnosis of MN with germline predisposition is of crucial clinical significance since it may tailor therapy, dictate the selection of donor for allogeneic hematopoietic stem cell transplantation (allo-HSCT), determine the conditioning regimen, enable relevant prophylactic measures and early intervention or contribute to avoid unnecessary or even harmful medication. Finally, it allows for genetic counseling and follow-up of at-risk family members. Identification of these patients in the clinical setting is challenging, as there is no consensus due to lack of evidence regarding the criteria defining the patients who should be tested for these conditions. In addition, even in cases with a strong suspicion of a MN with germline predisposition, no standard diagnostic algorithm is available. We present the first version of the Nordic recommendations for diagnostics, surveillance and management including considerations for allo-HSCT for patients and carriers of a germline mutation predisposing to the development of MNs.

In Silico Genetics Revealing 5 Mutations in CEBPA Gene Associated With Acute Myeloid Leukemia

Background:

Acute myeloid leukemia (AML) is an extremely heterogeneous malignant disorder; AML has been reported as one of the main causes of death in children. The objective of this work was to classify the most deleterious mutation in CCAAT/enhancer-binding protein-alpha (CEBPA) and to predict their influence on the functional, structural, and expression levels by various Bioinformatics analysis tools.

Methods:

The single nucleotide polymorphisms (SNPs) were claimed from the National Center for Biotechnology Information (NCBI) database and then submitted into various functional analysis tools, which were done to predict the influence of each SNP, followed by structural analysis of modeled protein followed by predicting the mutation effect on energy stability; the most damaging mutations were chosen for additional investigation by Mutation3D, Project hope, ConSurf, BioEdit, and UCSF Chimera tools.

Results:

A total of 5 mutations out of 248 were likely to be responsible for the structural and functional variations in CEBPA protein, whereas in the 3′-untranslated region (3′-UTR) the result showed that among 350 SNPs in the 3′-UTR of CEBPA gene, about 11 SNPs were predicted. Among these 11 SNPs, 65 alleles disrupted a conserved miRNA site and 22 derived alleles created a new site of miRNA.

Conclusions:

In this study, the impact of functional mutations in the CEBPA gene was investigated through different bioinformatics analysis techniques, which determined that R339W, R288P, N292S, N292T, and D63N are pathogenic mutations that have a possible functional and structural influence, therefore, could be used as genetic biomarkers and may assist in genetic studies with a special consideration of the large heterogeneity of AML.

Germline Predisposition to Hematolymphoid Neoplasia

OBJECTIVES

The 2017 Workshop of the Society for Hematopathology/European Association for Haematopathology aimed to review clinical cases with germline predisposition to hematolymphoid neoplasms.

METHODS

The Workshop Panel reviewed 51 cases with germline mutations and rendered consensus diagnoses. Of these, six cases were presented at the meeting by the submitting pathologists.

RESULTS

The cases submitted to the session covering germline predisposition included 16 cases with germline GATA2 mutations, 10 cases with germline RUNX1 mutations, two cases with germline CEBPA mutations, two germline TP53 mutations, and one case of germline DDX41 mutation. The most common diagnoses were acute myeloid leukemia (15 cases) and myelodysplastic syndrome (MDS, 14 cases).

CONCLUSIONS

The majority of the submitted neoplasms occurring in patients with germline predisposition were myeloid neoplasms with germline mutations in GATA2 and RUNX1. The presence of a germline predisposition mutation is not sufficient for a diagnosis of a neoplasm until the appearance of standard diagnostic features of a hematolymphoid malignancy manifest: in general, the diagnostic criteria for neoplasms associated with germline predisposition disorders are the same as those for sporadic cases.

Inherited thrombocytopenia and platelet disorders with germline predisposition to myeloid neoplasia

Advances in molecular genetic sequencing techniques have contributed to the elucidation of previously unknown germline mutations responsible for inherited thrombocytopenia (IT). Regardless of age of presentation and severity of symptoms related to thrombocytopenia and/or platelet dysfunction, a subset of patients with IT are at increased risk of developing myeloid neoplasms during their life time, particularly those with germline autosomal dominant mutations in RUNX1, ANKRD26, and ETV6. Patients may present with isolated thrombocytopenia and megakaryocytic dysmorphia or atypia on baseline bone marrow evaluation, without constituting myelodysplasia (MDS). Bone marrow features may overlap with idiopathic thrombocytopenic purpura (ITP) or sporadic MDS leading to misdiagnosis. Progression to myelodysplastic syndrome/ acute myeloid leukemia (MDS/AML) may be accompanied by progressive bi- or pancytopenia, multilineage dysplasia, increased blasts, cytogenetic abnormalities, acquisition of bi-allelic mutations in the underlying gene with germline mutation, or additional somatic mutations in genes associated with myeloid malignancy. A subset of patients may present with MDS/AML at a young age, underscoring the growing concern for evaluating young patients with MDS/AML for germline mutations predisposing to myeloid neoplasm. Early recognition of germline mutation and predisposition to myeloid malignancy permits appropriate treatment, adequate monitoring for disease progression, proper donor selection for hematopoietic stem cell transplantation, as well as genetic counseling of the affected patients and their family members. Herein, we describe the clinical and diagnostic features of IT with germline mutations predisposing to myeloid neoplasms focusing on mutations involving RUNX1, ANKRD26, and ETV6.

[Management of myelodysplastic syndromes in 2019: An update]

Myelodysplastic syndromes are a heterogeneous group of clonal myeloid disorders characterized by peripheral cytopenias and an increased risk of progression to acute myeloid leukemia. Inflammatory, auto-immune or syndromic symptoms can make the diagnosis difficult. Diagnosis is currently based on bone marrow cytology but cytogenetics and molecular features are currently overpassing their initial prognostic function (allowing early diagnosis and prediction of therapeutic response). The prognostic classification is based on the Revised International Prognostic Scoring System, which also provides guidance for therapeutic management. The treatment of low-risk myelodysplastic syndromes is based on the correction of cytopenias (erythropoiesis stimulating agents, transfusions, lenalidomide, etc.), whereas in high-risk group, the goal is the control of the leukemic clone (hypomethylating agents, allograft of hematopoietic stem cell transplantation). Other molecules are used to manage complications of cytopenias or transfusion (anti-infectious prophylaxis and treatments, martial chelation). New molecules are being studied with some interesting results (luspatercept, venetoclax). This article aims to provide an update on the knowledge that an internist should know for the practical management of myelodysplastic syndromes in 2019.

Epidemiology of acute myeloid leukemia: Recent progress and enduring challenges

Acute myeloid leukemia (AML) is a malignant disorder of the bone marrow which is characterized by the clonal expansion and differentiation arrest of myeloid progenitor cells. The age-adjusted incidence of AML is 4.3 per 100,000 annually in the United States (US). Incidence increases with age with a median age at diagnosis of 68 years in the US. The etiology of AML is heterogeneous. In some patients, prior exposure to therapeutic, occupational or environmental DNA-damaging agents is implicated, but most cases of AML remain without a clear etiology. AML is the most common form of acute leukemia in adults and has the shortest survival (5-year survival = 24%). Curative therapies, including intensive chemotherapy and allogeneic stem cell transplantation, are generally applicable to a minority of patients who are younger and fit, while most older individuals exhibit poor prognosis and survival. Differences in patient outcomes are influenced by disease characteristics, access to care including active therapies and supportive care, and other factors. After many years without therapeutic advances, several new therapies have been approved and are expected to impact patient outcomes, especially for older patients and those with refractory disease.

C-terminal RUNX1 mutation in familial platelet disorder with predisposition to myeloid malignancies

Here we report a C-terminal RUNX1 mutation in a family with platelet disorder and predisposition to myeloid malignancies. We identified the mutation c.866delG:p.Gly289Aspfs*22 (NM_001754) (RUNX1 b-isoform NM_001001890; c.785delG:p.Gly262Aspfs*22) using exome sequencing of samples obtained from eight members of a single family. The mutation found in our pedigree is within exon eight and the transactivation domain of RUNX1. One of the affected individuals developed myelodysplastic syndrome (MDS), which progressed to acute myelogenous leukemia (AML). A search for the second hit which led to the development of MDS and later AML in this individual revealed the PHF6 gene variant (exon9:c.872G > A:p.G291E; NM_001015877), BCORL1 (exon3:c.1111A > C:p.T371P; NM_001184772) and BCOR gene variant (exon4:c.2076dupT:p.P693fs; NM_001123383), which appear to be very likely second hits participating in the progression to myeloid malignancy.

Diagnostics and Prognostication of Myelodysplastic Syndromes

MDS are a heterogeneous and complex group of clonal hematological neoplasms arising from a hematopoietic stem cell, and characterized by ineffective hematopoiesis, resulting in increased apoptosis in the bone marrow and peripheral cytopenia, which involves one or more lineages. Epigenetic changes are reported as ‘founder’ mutations in the case of MDS. Its incidence in the general population has been reported as five new MDS diagnoses per 100,000 people. It affects men more frequently than it does women, and its incidence increases with age. The diagnostic classification, now in use, is the one of the World Health Organization, revised in August 2016. It recognizes six distinct entities in addition to a provisional entity of childhood. In most of the cases, diagnosis is based on the morphologic quantitative and qualitative evaluation of the peripheral blood and bone marrow using basic hematological techniques. Bone marrow biopsy and flow cytometric immunophenotyping also offer support for further diagnostic elucidation, while cytogenetics and molecular genetics are presently fully integrated into prognostication, treatment processes, and decision-making.

Clinic, pathogenic mechanisms and drug testing of two inherited thrombocytopenias, ANKRD26-related Thrombocytopenia and MYH9-related diseases

Inherited thrombocytopenias (ITs) are a heterogeneous group of disorders characterized by low platelet count resulting in impaired hemostasis. Patients can have spontaneous hemorrhages and/or excessive bleedings provoked by hemostatic challenges as trauma or surgery. To date, ITs encompass 32 different rare monogenic disorders caused by mutations of 30 genes. This review will focus on the major discoveries that have been made in the last years on the diagnosis, treatment and molecular mechanisms of ANKRD26-Related Thrombocytopenia and MYH9-Related Diseases. Furthermore, we will discuss the use a Thrombopoietin mimetic as a novel approach to treat the thrombocytopenia in these patients. We will propose the use of a new 3D bone marrow model to study the mechanisms of action of these drugs and to test their efficacy and safety in patients. The overall purpose of this review is to point out that important progresses have been made in understanding the pathogenesis of ANKRD26-Related Thrombocytopenia and MYH9-Related Diseases and new therapeutic approaches have been proposed and tested. Future advancement in this research will rely in the development of more physiological models to study the regulation of human platelet biogenesis, disease mechanisms and specific pharmacologic targets.

RUNX1 Mutations in Inherited and Sporadic Leukemia

RUNX1 is a recurrently mutated gene in sporadic myelodysplastic syndrome and leukemia. Inherited mutations in RUNX1 cause familial platelet disorder with predisposition to acute myeloid leukemia (FPD/AML). In sporadic AML, mutations in RUNX1 are usually secondary events, whereas in FPD/AML they are initiating events. Here we will describe mutations in RUNX1 in sporadic AML and in FPD/AML, discuss the mechanisms by which inherited mutations in RUNX1 could elevate the risk of AML in FPD/AML individuals, and speculate on why mutations in RUNX1 are rarely, if ever, the first event in sporadic AML.

Hereditary thrombocytopenias: a growing list of disorders

The introduction of high throughput sequencing (HTS) techniques greatly improved the knowledge of inherited thrombocytopenias (ITs) over the last few years. A total of 33 different forms caused by molecular defects affecting at least 32 genes have been identified; along with the discovery of new disease-causing genes, pathogenetic mechanisms of thrombocytopenia have been better elucidated. Although the clinical picture of ITs is heterogeneous, bleeding has been long considered the major clinical problem for patients with IT. Conversely, the current scenario indicates that patients with some of the most common ITs are at risk of developing additional disorders more dangerous than thrombocytopenia itself during life. In particular, MYH9 mutations result in congenital macrothrombocytopenia and predispose to kidney failure, hearing loss, and cataracts, MPL and MECOM mutations cause congenital thrombocytopenia evolving into bone marrow failure, whereas thrombocytopenias caused by RUNX1, ANKRD26, and ETV6 mutations are characterized by predisposition to hematological malignancies. Making a definite diagnosis of these forms is crucial to provide patients with the most appropriate treatment, follow-up, and counseling. In this review, the ITs known to date are discussed, with specific attention focused on clinical presentations and diagnostic criteria for ITs predisposing to additional illnesses. The currently available therapeutic options for the different forms of IT are illustrated.

Mean platelet diameter measurements to classify inherited thrombocytopenias

INTRODUCTION

Mean platelet volume (MPV) assists the differential diagnosis of inherited thrombocytopenia (IT) but lacks standardisation and varies between automated analysers. Classification of IT based on mean platelet diameter (MPD) has been proposed by an international collaborative study but has not been validated.

METHODS

To assess the applicability of MPD to classify forms of IT, digital images of blood films from patients with established genetic causes for IT were generated, and the MPD measured (ZEISS Axio-scanner and Image J software) by a blinded reviewer. Comparison was made to the proposed classification system.

RESULTS

Mean platelet volume was measured in thrombocytopenia with different genetic aetiologies, bilallelic BSS (bBSS) (n = 1), monoallelic BSS (mBSS) (n = 2), MYH9-related disorders (MYH9-RD) (n = 11), GFI1B-related thrombocytopenia (RT) (n = 15), FLI1-RT (n = 2), TUBB1-RT (n = 3), ITGA2B/ITGB3-RT (n = 1), RUNX1-RT (n = 2) and controls (n = 54). bBSS and 82% of MYH9-RD samples had MPD >4 μm which correlated with "IT with giant platelets." Only 55% of samples expected in the "large platelet group" had MPD meeting the classification cut-off (MPD >3.2 μm). FLI1-RT MPD were significantly larger than expected whilst ITGA2B/ITGB3-RT MPD were smaller than proposed. MPD in FPD/AML were "normal."

CONCLUSION

Platelet MPD measurements are a useful guide to classify IT, but the time taken to record measurements may limit clinical applicability.

Familial myelodysplastic syndrome/acute myeloid leukemia

A growing number of inherited genetic loci that contribute to myelodysplastic syndrome/acute myeloid leukemia (MDS/AML) development in both children as well as adults are rapidly being identified. In recognition of the clinical impact of this emerging field, the World Health Organization, National Comprehensive Cancer Network, and European LeukemiaNet have all added consideration of inherited predisposition to MDS/AML classification and management. Study of these disorders is providing unique insight into the biology of both sporadic and familial MDS/AML. International collaborative efforts to store germline tissue, document family histories, and pool data are essential to progress in diagnosing and treating both hereditary and sporadic forms of MDS/AML.

Familial Myelodysplastic/Acute Leukemia Syndromes-Myeloid Neoplasms with Germline Predisposition

Although most cases of myeloid neoplasms are sporadic, a small subset has been associated with germline mutations. The 2016 revision of the World Health Organization classification included these cases in a myeloid neoplasm group with a predisposing germline mutational background. These patients must have a different management and their families should get genetic counseling. Cases identification and outline of the major known syndromes characteristics will be discussed in this text.

Bone marrow pathologic abnormalities in familial platelet disorder with propensity for myeloid malignancy and germline RUNX1 mutation

A subset of patients with familial platelet disorder with propensity to myeloid malignancy and germline RUNX1 mutation develops hematological malignancies, often myelodysplastic syndrome/acute myeloid leukemia, currently recognized in the 2016 WHO classification. Patients who develop hematologic malignancies are typically young, respond poorly to conventional therapy, and need allogeneic stem cell transplant from non-familial donors. Understanding the spectrum of bone marrow morphologic and genetic findings in these patients is critical to ensure diagnostic accuracy and develop criteria to recognize the onset of hematologic malignancies, particularly myelodysplastic syndrome. However, bone marrow features remain poorly characterized. To address this knowledge gap, we analyzed the clinicopathologic and genetic findings of 11 patients from 7 pedigrees. Of these, 6 patients did not develop hematologic malignancies over a 22-month follow-up period; 5 patients developed hematologic malignancies (3 acute myeloid leukemia; 2 myelodysplastic syndrome). All patients had thrombocytopenia at initial presentation. All 6 patients who did not develop hematologic malignancies showed baseline bone marrow abnormalities: low-for-age cellularity (n=4), dysmegakaryopoiesis (n=5), megakaryocytic hypoplasia/hyperplasia (n=5), and eosinophilia (n=4). Two patients had multiple immunophenotypic alterations in CD34-positive myeloblasts; 1 patient had clonal hematopoiesis. In contrast, patients who developed hematologic malignancies had additional cytopenia(s) (n=4), abnormal platelet granulation (n=5), bone marrow hypercellularity (n=4), dysplasia in ≥2 lineages including megakaryocytes (n=3) and acquired clonal genetic aberrations (n=5). In conclusion, our study demonstrated that specific bone marrow abnormalities and acquired genetic alterations may be harbingers of progression to hematological malignancies in patients with familial platelet disorder with germline RUNX1 mutation.

Bleeding is not the main clinical issue in many patients with inherited thrombocytopaenias

Bleeding diathesis has been considered for a long time the main clinical issue impacting the lives of patients affected by inherited thrombocytopaenias. However, the number of known inherited thrombocytopaenias greatly increased in recent years, and careful evaluation of hundreds of patients affected by these 'new' disorders revealed that most of them are at risk of developing additional life-threatening disorders during childhood or adult life. These additional disorders are usually more serious and dangerous than low platelet count. For instance, it is known that mutations in RUNX1, ANKRD26 and ETV6 cause congenital thrombocytopaenia, but we now know that they also predispose to haematological malignancies. Similarly, MYH9 mutations result in congenital thrombocytopaenia and increase the risk of developing kidney failure, cataracts and hearing loss at a later stage, while MPL mutations cause a congenital thrombocytopaenia that almost always evolves into deadly bone marrow failure. Thus, identification of patients with these disorders is essential for evaluation of their prognosis, enabling effective genetic counselling, personalizing follow-up and giving appropriate treatments in case of development of additional diseases. Careful clinical evaluation and peripheral blood film examination are extremely useful tools in guiding the diagnostic process and identifying the candidate genes to be sequenced.

Hematopoietic transcription factor mutations: important players in inherited platelet defects

Transcription factors (TFs) are proteins that bind to specific DNA sequences and regulate expression of genes. The molecular and genetic mechanisms in most patients with inherited platelet defects are unknown. There is now increasing evidence that mutations in hematopoietic TFs are an important underlying cause for defects in platelet production, morphology, and function. The hematopoietic TFs implicated in patients with impaired platelet function and number include runt-related transcription factor 1, Fli-1 proto-oncogene, E-twenty-six (ETS) transcription factor (friend leukemia integration 1), GATA-binding protein 1, growth factor independent 1B transcriptional repressor, ETS variant 6, ecotropic viral integration site 1, and homeobox A11. These TFs act in a combinatorial manner to bind sequence-specific DNA within promoter regions to regulate lineage-specific gene expression, either as activators or repressors. TF mutations induce rippling downstream effects by simultaneously altering the expression of multiple genes. Mutations involving these TFs affect diverse aspects of megakaryocyte biology, and platelet production and function, culminating in thrombocytopenia and platelet dysfunction. Some are associated with predisposition to hematologic malignancies. These TF variants may occur more frequently in patients with inherited platelet defects than generally appreciated. This review focuses on alterations in hematopoietic TFs in the pathobiology of inherited platelet defects.

Non-infectious chemotherapy-associated acute toxicities during childhood acute lymphoblastic leukemia therapy

During chemotherapy for childhood acute lymphoblastic leukemia, all organs can be affected by severe acute side effects, the most common being opportunistic infections, mucositis, central or peripheral neuropathy (or both), bone toxicities (including osteonecrosis), thromboembolism, sinusoidal obstruction syndrome, endocrinopathies (especially steroid-induced adrenal insufficiency and hyperglycemia), high-dose methotrexate-induced nephrotoxicity, asparaginase-associated hypersensitivity, pancreatitis, and hyperlipidemia. Few of the non-infectious acute toxicities are associated with clinically useful risk factors, and across study groups there has been wide diversity in toxicity definitions, capture strategies, and reporting, thus hampering meaningful comparisons of toxicity incidences for different leukemia protocols. Since treatment of acute lymphoblastic leukemia now yields 5-year overall survival rates above 90%, there is a need for strategies for assessing the burden of toxicities in the overall evaluation of anti-leukemic therapy programs.

Bone marrow morphology and disease progression in congenital thrombocytopenia: a detailed clinicopathologic and genetic study of eight cases

Patients with congenital thrombocytopenia have an increased risk of developing myeloid neoplasms. In these cases, the morphologic distinction between disease at baseline and at progression is challenging. This report analyzes clinicopathologic features of congenital thrombocytopenia with long-term follow-up at one referral center. Records from the last 20 years were searched for cases of congenital thrombocytopenia with bone marrow biopsies and peripheral blood smears. The clinical, morphologic, immunophenotypic, and molecular features were analyzed. Six adult and two pediatric patients were identified (six male, two female). Age range at first biopsy was 1-47 (median, 31) years. Underlying diseases included thrombocytopenia-absent radius syndrome, congenital thrombocytopenia with radial-ulnar synostosis, MYH9-related disorder, shortened telomere syndrome, congenital thrombocytopenia with ANKRD26 mutation, and familial platelet disorder with predisposition to acute myeloid leukemia. Four patients had myelodysplastic/myeloproliferative neoplasm-like marrow changes such as hypercellularity, increased myeloid to erythroid ratio, numerous micromegakaryocytes (highlighted by CD42b), and marrow fibrosis. Two patients had marrow hypoplasia and two had unremarkable marrow morphology. Three patients-all in the myelodysplastic/myeloproliferative neoplasm-like group-developed disease progression characterized by erythroid and myeloid dysplasia, elevated bone marrow blasts, and new cytogenetic abnormalities. Unlike non-familial myeloid neoplasms, congenital thrombocytopenia patients in the myelodysplastic/myeloproliferative neoplasm-like group had a long and indolent clinical course (average age at disease progression, 47 years). In summary, three distinct morphologic types of congenital thrombocytopenia were identified: a hyperplastic myelodysplastic/myeloproliferative neoplasm-like group, a hypoplastic bone marrow failure-like group, and a group with relatively normal marrow morphology. Emergence of cytogenetic abnormalities and dysplasia in non-megakaryocyte lineages correlated with disease progression.

Telomerase and telomere biology in hematological diseases: A new therapeutic target

Telomeres are structures confined at the ends of eukaryotic chromosomes. With each cell division, telomeric repeats are lost because DNA polymerases are incapable to fully duplicate the very ends of linear chromosomes. Loss of repeats causes cell senescence, and apoptosis. Telomerase neutralizes loss of telomeric sequences by adding telomere repeats at the 3' telomeric overhang. Telomere biology is frequently associated with human cancer and dysfunctional telomeres have been proved to participate to genetic instability. This review covers the information on telomerase expression and genetic alterations in the most relevant types of hematological diseases. Telomere erosion hampers the capability of hematopoietic stem cells to effectively replicate, clinically resulting in bone marrow failure. Furthermore, telomerase mutations are genetic risk factors for the occurrence of some hematologic cancers. New discoveries in telomere structure and telomerase functions have led to an increasing interest in targeting telomeres and telomerase in anti-cancer therapy.

The wide-ranging clinical implications of the short telomere syndromes

There is an increasing number of inherited disorders in which excessive telomere shortening underlies the molecular defect, with dyskeratosis congenita (DC) being the archetypal short telomere syndrome. DC is classically described as a mucocutaneous triad of oral leukoplakia, nail dystrophy and abnormal skin pigmentation. However, excessive telomere shortening can affect almost any organ system, so the clinical manifestations are protean, including developmental delay, cerebellar hypoplasia, exudative retinopathy, aplastic anaemia, acute myeloid leukaemia, idiopathic pulmonary fibrosis, idiopathic hepatic cirrhosis, head and neck cancer and dental abnormalities, and may be multi-systemic. Undiagnosed patients may be seen by essentially any medical subspecialist. Correct diagnosis is important to ensure appropriate management, and for initiating investigations to identify affected family members. Treatment is often supportive, with transplantation offering cure for pulmonary fibrosis or bone marrow failure. Higher rates of mortality and morbidity with transplantation often require regimen alterations, underscoring the need for correct diagnosis. Short telomeres result from mutations in genes essential for telomere maintenance (e.g. genes encoding subunits of the telomerase enzyme complex). Disease severity reflects not only the severity of the defect, but also the inheritance of short telomeres, giving rise to incomplete penetrance and genetic anticipation. Attendees of the inaugural Australian Short Telomere Syndrome Conference were updated on the current scientific and clinical understanding of these disorders, and discussed the best approach for management of these patients in the Australian context. This review will include recommendations from the conference and aims to increase awareness of short telomere disorders.

The genetics of myelodysplastic syndrome: from clonal haematopoiesis to secondary leukaemia

Myelodysplastic syndrome (MDS) is a clonal disease that arises from the expansion of mutated haematopoietic stem cells. In a spectrum of myeloid disorders ranging from clonal haematopoiesis of indeterminate potential (CHIP) to secondary acute myeloid leukaemia (sAML), MDS is distinguished by the presence of peripheral blood cytopenias, dysplastic haematopoietic differentiation and the absence of features that define acute leukaemia. More than 50 recurrently mutated genes are involved in the pathogenesis of MDS, including genes that encode proteins involved in pre-mRNA splicing, epigenetic regulation and transcription. In this Review we discuss the molecular processes that lead to CHIP and further clonal evolution to MDS and sAML. We also highlight the ways in which these insights are shaping the clinical management of MDS, including classification schemata, prognostic scoring systems and therapeutic approaches.

Clinical Assessment and Diagnosis of Germline Predisposition to Hematopoietic Malignancies: The University of Chicago Experience

With the increasing use of clinical genomics to guide cancer treatment and management, there is a rise in the identification of germline cancer predisposition syndromes and a critical need for patients with germline findings to be referred for surveillance and care. The University of Chicago Hematopoietic Malignancies Cancer Risk Team has established a unique approach to patient care for individuals with hereditary hematologic malignancies through close communication and coordination between our pediatric and adult programs. Dedicated program members, including physicians, nurses, genetic counselors, and clinical research assistants, screen individuals for cancer predisposition at initial diagnosis through survivorship, in addition to testing individuals with an established family history of a cancer predisposition syndrome. Sample procurement, such as a skin biopsy at the time of bone marrow aspirate/biopsy in individuals with a positive screen, has facilitated timely identification of clinical germline findings or has served as a pipeline for translational research. Our integrated translational research program has led to the identification of novel syndromes in collaboration with other investigators, which have been incorporated iteratively into our clinical pipeline. Individuals are referred for clinical assessment based on personal and family history, identification of variants in susceptibility genes via molecular tumor testing, and during evaluation for matched related allogeneic stem cell transplantation. Upon referral, genetic counseling incorporates education with mindfulness of the psychosocial issues surrounding germline testing at different ages. The training and role of genetic counselors continues to grow, with the discovery of new predisposition syndromes, in the age of improved molecular diagnostics and new models for service delivery, such as telemedicine. With the identification of new syndromes that may predispose individuals to hematologic malignancies, surveillance guidelines will continue to evolve and may differ between children and adults. Thus, utilizing a collaborative approach between the pediatric and adult oncology programs facilitates care within families and optimizes the diagnosis and care of individuals with cancer predisposition syndromes.