Genetic predisposition syndromes: when should they be considered in the work-up of MDS?

The role of genetic factors in pediatric myelodysplastic syndromes with different outcomes

BACKGROUND

Pediatric myelodysplastic syndromes (MDS) are rare disorders with an unrevealed pathogenesis. Our aim is to explore the role of genetic factors in the pathogenesis of MDS in children with different outcomes and to discover the correlation between genetic features and clinical outcomes as well as disease characteristics.

METHODS

We conducted an analysis of archived genetic data from 26 patients diagnosed with pediatric MDS at our institution between 2015 and 2021, examining the association between different genetic characteristics and clinical manifestations as well as prognosis. Additionally, We presented three cases with distinct genetic background and outcomes as examples to elaborate the role of genetic factors in pediatric MDS with different prognoses.

RESULTS

Genetic variations were detected in 13 out of the 26 patients, including 8 patients with co-occurrence of somatic and germline mutations (CSGMs) and 5 patients with somatic mutations alone. Our analysis revealed that advanced MDS (4/8, 50% vs. 1/5, 20% and 4/11, 36.4%), PD (3/8, 37.5% vs. 1/5, 20% and 1/11 9.1%), and TD (6/8, 75% vs. 2/5, 40% and 2/11, 18.2%) were more common in patients with CSGMs than those with somatic mutations alone or without any mutations. We also found out in our study that 8 patients with CSGMs had evidently different clinical outcomes, and we presented 3 of them as examples for elaboration. Case 1 with germline and somatic mutations of unknown significance had a relatively slow disease course and a good prognosis. Case 2 with compound heterozygous germline SBDS variants and somatic mutations like del20q had a stable disease course and a reversed outcome. Case 3 with a germline GATA2 variant and somatic mutations including - 7 had a rapidly progressive disease course and a worst prognosis.

CONCLUSION

Our findings indicate that genetic background of pediatric MDS is closely linked with disease characteristics as well as outcomes and that CSGMs may lead to disease progression. It should be emphasized that the interaction between certain germline variants and somatic mutations, such as SBDS and del20q, may result in hematopoietic stem cell adaptation (improved hematopoiesis) and reversed clinical outcomes, which can facilitate the development of targeted therapy.

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.

Two-Time Multiplexed Targeted Next-Generation Sequencing Might Help the Implementation of Germline Screening Tools for Myelodysplastic Syndromes/Hematologic Neoplasms

Next-generation sequencing (NGS) tools have importantly helped the classification of myelodysplastic syndromes (MDS), guiding the management of patients. However, new concerns are under debate regarding their implementation in routine clinical practice for the identification of germline predisposition. Cost-effective targeted NGS tools would improve the current standardized studies and genetic counseling. Here, we present our experience in a preliminary study detecting variants using a two-time multiplexed library strategy. Samples from different MDS patients were first mixed before library preparation and later multiplexed for a sequencing run. Two different mixes including a pool of three (3×) and four (4×) samples were evaluated. The filtered variants found in the individually sequenced samples were compared with the variants found in the two-time multiplexed studies to determine the detection efficiency scores. The same candidate variants were found in the two-time multiplexed studies in comparison with the individual tNGS. The variant allele frequency (VAF) values of the candidate variants were also compared. No significant differences were found between the expected and observed VAF percentages in both the 3× (p-value 0.74) and 4× (p-value 0.34) multiplexed studies. Our preliminary results suggest that the two-time multiplexing strategy might have the potential to help reduce the cost of evaluating germline predisposition.

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

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

The Secondary Myelodysplastic Neoplasms (MDS) Jigsaw

There is a great deal of controversy in the hematologic community regarding the classification of secondary myelodysplastic neoplasms (MDSs). Current classifications are based on the presence of genetic predisposition and MDS post-cytotoxic therapy (MDS-pCT) etiologies. However, since these risk factors are not exclusive for secondary MDSs and there are multiple overlapping scenarios, a comprehensive and definitive classification is yet to come. In addition, a sporadic MDS might arise after a primary tumor fulfills the diagnostic criteria of MDS-pCT without a causative cytotoxicity. In this review, we describe the triggering pieces of a secondary MDS jigsaw: previous cytotoxic therapy, germline predisposition and clonal hematopoiesis. Epidemiological and translational efforts are needed to put these pieces together and ascertain the real weight of each of these pieces in each MDS patient. Future classifications must contribute to understanding the role of secondary MDS jigsaw pieces in different concomitant or independent clinical scenarios associated with the primary tumor.

Clinical implementation of genetic testing in adults for hereditary hematologic malignancy syndromes

PURPOSE

As research on hereditary hematologic malignancy syndromes (HHMS) are accumulating, cancer genetics clinics are identifying more adult hematology patients with an inherited component to their disease. However, investigations for HHMS are complex, and there is no formal consensus on genetic testing criteria.

METHODS

We developed genetic testing criteria for adult hematology patients through a comprehensive literature review and our experience at the Princess Margaret Cancer Centre. We validated our criteria by applying them retrospectively to patients referred to our clinic for HHMS assessment.

RESULTS

Our genetic testing criteria are comprehensive of myeloid malignancies, lymphoid malignancies, and bone marrow failure, including age at diagnosis, family history, and genetic test results in blood and bone marrow. Of the 104 patients who met the criteria, 26% had at least 1 actionable variant in any gene associated with an increased risk of cancer and 13% had an actionable variant resulting in an HHMS diagnosis. A total of 15 patients had incidental findings, including 11 patients with a pathogenic variant associated with carrier status for an autosomal recessive disorder and 4 patients with a mosaic result.

CONCLUSION

Our high gene positivity rate shows the utility of a broad approach to germline testing in an adult hematology population.

Assessment of All-Cause Cancer Incidence Among Individuals With Preeclampsia or Eclampsia During First Pregnancy

IMPORTANCE

Preeclampsia or eclampsia (preeclampsia/eclampsia) during pregnancy induces major physiological changes and may be associated with specific cancer occurrences in later life. The current data regarding the association between preeclampsia/eclampsia and cancer are heterogeneous, and cancer risk after preeclampsia/eclampsia could be different depending on the organ. These uncertainties warrant reexamination of the association between preeclampsia/eclampsia and the risk of cancer overall and by specific cancer type.

OBJECTIVE

To evaluate the risk of cancer, overall and by type, after preeclampsia/eclampsia during a first pregnancy.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used data from the French hospital discharge database to identify all female individuals who had a pregnancy-associated hospitalization between January 1, 2010, and December 31, 2019. To allow a minimum of 2 years for the detection of medical history, individuals with a first detected pregnancy before January 1, 2012, were excluded, as were those with a cancer-associated hospitalization before or during their first detected pregnancy. Exposures, comorbidities, and occurrences of cancer were evaluated using data from the medico-administrative registers of hospitalizations in private and public French hospitals. Cox proportional hazards models were used to analyze cancer risk according to the occurrence of preeclampsia/eclampsia during first pregnancy.

EXPOSURES

Preeclampsia/eclampsia-associated hospitalization during the first detected pregnancy.

MAIN OUTCOMES AND MEASURES

The primary outcome was the incidence of cancer, including myelodysplastic or myeloproliferative diseases, after a first pregnancy with and without preeclampsia/eclampsia.

RESULTS

After exclusions, a total of 4 322 970 female individuals (mean [SD] age at first detected pregnancy, 29.6 [6.2] years) with and without preeclampsia/eclampsia during their first pregnancy were included. Of those, 45 523 individuals (1.1%) were diagnosed with preeclampsia/eclampsia during their first detected pregnancy. The maximum follow-up was 8 years, during which 29 173 individuals (0.7%) were diagnosed with cancer. No significant difference in overall cancer incidence was found between those with and without preeclampsia/eclampsia during their first pregnancy (adjusted hazard ratio [AHR], 0.94; 95% CI, 0.84-1.05). Preeclampsia/eclampsia was associated with an increase in the risk of myelodysplastic syndromes or myeloproliferative diseases (AHR, 2.43; 95% CI, 1.46-4.06) and kidney cancer (AHR, 2.19; 95% CI, 1.09-4.42) and a decrease in the risk of breast cancer (AHR, 0.79; 95% CI, 0.62-0.99) and cervical cancer (AHR, 0.75; 95% CI, 0.58-0.96).

CONCLUSIONS AND RELEVANCE

In this study, a history of preeclampsia/eclampsia during first pregnancy was associated with an increase in the incidence of myelodysplastic or myeloproliferative diseases and kidney cancer and a decrease in the incidence of cervical and breast cancers. These associations might reflect an underlying common factor among preeclampsia/eclampsia and these pathologies and/or an association between preeclampsia/eclampsia and the development of these cancers.

The Emerging Role of Hematopathologists and Molecular Pathologists in Detection, Monitoring, and Management of Myeloid Neoplasms with Germline Predisposition

PURPOSE OF REVIEW

Awareness, widespread availability, and routine use of sequencing techniques in work-up of myelodysplastic syndromes and acute myeloid leukemia have facilitated increased recognition of these entities arising in a background of germline predisposition disorders (GPD).

RECENT FINDINGS

The latest revisions to the WHO classification of myeloid neoplasms incorporate "myeloid neoplasms with germline predisposition" as a separate entity due to the therapeutic implications of this diagnosis. It has become apparent that some of these entities have unique recognizable morphologic findings that can be challenging to interpret at time. Hence, much needs to be studied, posing a new layer of complexity to hematopathologists and oncologists. A thorough understanding of cytogenetic and molecular findings during disease evolution is essential. Consequently, hematopathologists and molecular pathologists play an increasing role in recognition of bone marrow morphologic features that help in recognition of underlying GPD, monitoring, and prompt identification of progression.

Myelodysplastic syndrome with genetic predisposition

Myelodysplastic syndrome (MDS) refers to a heterogeneous group of clonal blood disorders characterized by ineffective hematopoiesis, cytopenia, dysplasia, and an increased risk of acute myeloid leukemia (AML). A growing number of inherited genetic loci that contribute to MDS/AML development are rapidly being identified. As genetic sequencing has become increasingly integrated into clinical practice, clearly defined syndromes have emerged, known as the MDS/AML predisposition syndrome. With more patients and families being identified with predisposing conditions, knowledge of the approach of evaluating and managing MDS with genetic predisposition is increasingly essential. This article reviews MDS with genetic predisposition and the practical aspects of management in patients with predisposition syndrome.

When Should We Think of Myelodysplasia or Bone Marrow Failure in a Thrombocytopenic Patient? A Practical Approach to Diagnosis

Thrombocytopenia can arise from various conditions, including myelodysplastic syndromes (MDS) and bone marrow failure (BMF) syndromes. Meticulous assessment of the peripheral blood smear, identification of accompanying clinical conditions, and characterization of the clinical course are important for initial assessment of unexplained thrombocytopenia. Increased awareness is required to identify patients with suspected MDS or BMF, who are in need of further investigations by a step-wise approach. Bone marrow cytomorphology, histopathology, and cytogenetics are complemented by myeloid next-generation sequencing (NGS) panels. Such panels are helpful to distinguish reactive cytopenia from clonal conditions. MDS are caused by mutations in the hematopoietic stem/progenitor cells, characterized by cytopenia and dysplasia, and an inherent risk of leukemic progression. Aplastic anemia (AA), the most frequent acquired BMF, is immunologically driven and characterized by an empty bone marrow. Diagnosis remains challenging due to overlaps with other hematological disorders. Congenital BMF, certainly rare in adulthood, can present atypically with thrombocytopenia and can be misdiagnosed. Analyses for chromosome fragility, telomere length, and germline gene sequencing are needed. Interdisciplinary expert teams contribute to diagnosis, prognostication, and choice of therapy for patients with suspected MDS and BMF. With this review we aim to increase the awareness and provide practical approaches for diagnosis of these conditions in suspicious cases presenting with thrombocytopenia.

Next-Generation Sequencing of DDX41 in Myeloid Neoplasms Leads to Increased Detection of Germline Alterations

Previously considered rare, inherited hematologic malignancies are increasingly identified. Germline mutations in the RNA helicase DDX41 predispose to increased lifetime risks of myeloid neoplasms with disease often occurring later in life which presents challenges for germline recognition. To improve identification of germline DDX41, individuals presenting with ≥1 DDX41 alteration on an institutional MDS/AML next-generation sequencing based panel with at least one at >40% variant allele frequency were flagged for review and genetic counseling referral. Of 5,801 individuals, 90 (1.5%) had ≥1 DDX41 mutation(s) identified. Thirty-eight (42%) patients with a median age of 66 years were referred for genetic counseling; thirty-one were male (81.5%). Thirty-five (92%) referred patients elected to pursue germline evaluation and in 33/35 (94%) a germline DDX41 variant was confirmed. Twenty-two patients (66%) with germline variants reported antecedent cytopenias, seven (21%) had a prior history of malignancy, and twenty-seven (82%) reported a family history of cancer. Predictive genetic testing for healthy family members under consideration as stem cell transplant donors was successfully performed in 11 family members, taking an average of 15 days. Near-heterozygous DDX41 mutations identified on next-generation sequencing, particularly nonsense/frameshift variants or those at recurrent germline “hot spots” are highly suggestive of a germline mutation. Next-generation sequencing screening is a feasible tool to screen unselected myeloid neoplasms for germline DDX41 mutations, enabling timely and appropriate care.

GPX3 methylation is associated with hematologic improvement in low-risk myelodysplastic syndrome patients treated with Pai-Neng-Da

Objective

The aim of this prospective randomized controlled clinical trial was to explore the relationship between GPX3 methylation and Pai-Neng-Da (PND) in the treatment of patients with low-risk myelodysplastic syndrome (MDS).

Methods

There were 82 low-risk MDS patients who were randomly divided into the following two groups: androl, thalidomide, and PND capsule (ATP group, n = 41); or androl and thalidomide (AT group, n = 41). Hemoglobin and neutrophil and platelet counts and changes in GPX3 methylation level were assessed.

Results

The plasma hemoglobin level increased in both groups after treatment. However, the platelet count increased only in the ATP group. Patients in the ATP group had a better platelet response than the AT group, and GPX3 methylation markedly decreased after treatment with ATP but not after treatment with AT. Moreover, male patients had a significantly lower GPX3 methylation level than female patients, while platelet counts from male patients increased dramatically after the ATP regimens compared with female patients. GPX3 methylation changes were negatively correlated with platelet changes in ATP group.

Conclusion

PND can improve hematological parameters and decrease the GPX3 methylation level. Decreasing GPX3 methylation is associated with the hematologic response that includes platelet in GPX3 methylation.

China Clinical Trial Bureau (ChiCTR;http://www.chictr.org.cn/) registration number: ChiCTR-IOR-15006635.

AML through the prism of molecular genetics

Modern management of acute myeloid leukaemia (AML) relies on the integration of phenotypic and genetic data to assign classification, establish prognosis, enhance monitoring and guide treatment. The prism through which we can now disperse a patient's leukaemia, interpret and apply our understanding has fundamentally changed since the completion of the first whole-genome sequencing (WGS) of an AML patient in 2008 and where possible, many clinicians would now prefer to delay treatment decisions until the karyotype and genetic status of a new patient is known. The success of global sequencing initiatives such as The Cancer Genome Atlas (TCGA) have brought us significantly closer to cataloguing the full spectrum of coding mutations involved in human malignancy. Indeed, genetic capability has raced ahead of our capacity to apply much of this knowledge into clinical practice and we are in the peculiar position of having routine access to genetic information on an individual patient's leukaemia that cannot be reliably interpreted or utilised. This is a measure of how rapid the progress has been, and this rate of change is likely to continue into the foreseeable future as research intensifies on the non-coding genome and the epigenome, as we scrutinise disease at a single cell level, and as initiatives like Beat AML and the Harmony Alliance progress. In this review, we will examine how interrogation of the coding genome is revolutionising our understanding of AML and improving our ability to underscore differences between paediatric and adult onset, sporadic and inherited forms of disease. We will look at how this knowledge is informing improvements in outcome prediction and the development of novel treatments, bringing us a step closer to personalised therapy for myeloid malignancy.

Genetic predisposition to MDS: diagnosis and management

Myelodysplastic syndromes (MDS) are a heterogeneous group of disorders characterized by clonal hematopoiesis with a propensity to evolve into acute myeloid leukemia. MDS presenting in children and young adults is associated with features clinically and biologically distinct from MDS arising in older adults. MDS presenting in children and young adults is associated with a higher likelihood of an underlying genetic predisposition; however, genetic predisposition is increasingly recognized in a subset of older adults. The diagnosis of a genetic predisposition to MDS informs clinical care and treatment selection. Early diagnosis allows a tailored approach to management and surveillance. Genetic testing now offers a powerful diagnostic approach but also poses new challenges and caveats. Clinical expertise in these disorders together with scientific expertise regarding the affected genes is essential for diagnosis. Understanding the basic mechanisms of genetic predisposition to myeloid malignancies may inform surveillance strategies and lead to novel therapies. The cases presented in this article illustrate challenges to the diagnosis of germline genetic predisposition to MDS and how the diagnosis affects clinical management and treatment.

Bone Marrow Morphology Associated With Germline RUNX1 Mutations in Patients With Familial Platelet Disorder With Associated Myeloid Malignancy

Germline mutations in RUNX1 result in autosomal dominant familial platelet disorder with associated myeloid malignancy (FPDMM). To characterize the hematopathologic features associated with a germline RUNX1 mutation, we reviewed a total of 42 bone marrow aspirates from 14 FPDMM patients, including 24 cases with no cytogenetic clonal abnormalities, and 18 with clonal karyotypes or leukemia. We found that all aspirate smears had ≥10% atypical megakaryocytes, predominantly characterized by small forms with hypolobated and eccentric nuclei, and forms with high nuclear-to-cytoplasmic ratios. Core biopsies showed variable cellularity and variable numbers of megakaryocytes with similar features to those in the aspirates. Granulocytic and/or erythroid dysplasia (≥10% cells per lineage) were present infrequently. Megakaryocytes with separate nuclear lobes were increased in patients with myelodysplastic syndrome (MDS) and acute leukemia. Comparison to an immune thrombocytopenic purpura cohort confirms increased megakaryocytes with hypolobated eccentric nuclei in FPDMM patients. As such, patients with FPDMM often have atypical megakaryocytes with small hypolobated and eccentric nuclei even in the absence of clonal cytogenetic abnormalities; these findings are related to the underlying RUNX1 germline mutation and not diagnostic of MDS. Isolated megakaryocytic dysplasia in patients with unexplained thrombocytopenia should raise the possibility of an underlying germline RUNX1 mutation.

An Integrated Regulatory Network Based on Comprehensive Analysis of mRNA Expression, Gene Methylation and Expression of Long Non-coding RNAs (lncRNAs) in Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) are a heterogeneous group of disorders characterized by ineffective hematopoiesis, defective differentiation of hematopoietic precursors, and expansion of the abnormal clones. The prevalence of MDS has raised great concerns worldwide, but its pathogenetic mechanisms remain elusive. To provide insights on novel biomarkers for the diagnosis and therapy of MDS, we performed high-throughput genome-wide mRNA expression profiling, DNA methylation analysis, and long non-coding RNAs (lncRNA) analysis on bone marrows from four MDS patients and four age-matched healthy controls. We identified 1,937 differentially expressed genes (DEGs), 515 methylated genes, and 214 lncRNA that showed statistically significant differences. As the most significant module-related DEGs, TCL1A, PTGS2, and MME were revealed to be enriched in regulation of cell differentiation and cell death pathways. In addition, the GeneGo pathway maps identified by top DEGs were shown to converge on cancer, immunoregulation, apoptosis and regulation of actin cytoskeleton, most of which are known contributors in MDS etiology and pathogenesis. Notably, as potential biomarkers for diagnosis of MDS, four specific genes (ABAT, FADD, DAPP1, and SMPD3) were further subjected to detailed pathway analysis. Our integrative analysis on mRNA expression, gene methylation and lncRNAs profiling facilitates further understanding of the pathogenesis of MDS, and may promote the diagnosis and novel therapeutics for this disease.

Diagnostic algorithm for lower-risk myelodysplastic syndromes

Rapid advances over the past decade have uncovered the heterogeneous genomic and immunologic landscape of myelodysplastic syndromes (MDS). This has led to notable improvements in the accuracy and timing of diagnosis and prognostication of MDS, as well as the identification of possible novel targets for therapeutic intervention. For the practicing clinician, however, this increase in genomic, epigenomic, and immunologic knowledge needs consideration in a "real-world" context to aid diagnostic specificity. Although the 2016 revision to the World Health Organization classification for MDS is comprehensive and timely, certain limitations still exist for day-to-day clinical practice. In this review, we describe an up-to-date diagnostic approach to patients with suspected lower-risk MDS, including hypoplastic MDS, and demonstrate the requirement for an "integrated" diagnostic approach. Moreover, in the era of rapid access to massive parallel sequencing platforms for mutational screening, we suggest which patients should undergo such analyses, when such screening should be performed, and how those data should be interpreted. This is particularly relevant given the recent findings describing age-related clonal hematopoiesis.

Acquired Aplastic Anemia: What Have We Learned and What Is in the Horizon?

Acquired aplastic anemia (aAA) characterized by peripheral pancytopenia and bone marrow aplasia is a rare and serious disorder. Differential diagnosis includes constitutional bone marrow failure syndromes and myelodysplastic disorders. Autoimmune reaction to altered hematopoietic stem cells highlights the underlying mechanism. Matched related donor allogeneic hematopoietic stem cell transplantation is the ideal pediatric treatment; alternative approaches include immunosuppressive therapy and use of eltrombopag. Progression to clonal disorders can occur. Recently, alternative donor hematopoietic stem cell transplantation outcomes have significantly improved. Despite advances, aAA continues to be a challenge for hematologists.

Atypical erythroblastosis in a patient with Diamond-Blackfan anemia who developed del(20q) myelodysplasia

Diamond-Blackfan anemia (DBA) is a congenital red cell aplasia arising from ribosomal protein (RP) defects. Affected patients present with neonatal anemia, occasional dysmorphism, and cancer predisposition. An anemic newborn was diagnosed with DBA due to RPL5 mutation (c.473_474del, p.K158SfsX26). Refractory anemia required regular transfusions and iron chelation therapy. Pancytopenia occurred at age 16 years. Bone-marrow studies showed myelodysplasia, erythroblastosis, and clonal evolution of del(20)(q11.2q13.3). Severe anemia required transfusions. Del(20q), including the L3MBTL1 gene, is reported to be relevant to the hematological phenotype of Shwachman-Diamond syndrome. A combined defect of RPL5 and L3MBTL1 may contribute to the aberrant erythropoiesis in the present case.

Uncoding the genetic heterogeneity of myelodysplastic syndrome

Myelodysplastic syndrome (MDS) is a clinically heterogeneous disease characterized by functional impairment of hematopoiesis and abnormal bone marrow morphology. The type and severity of hematopoietic dysfunction in MDS are highly variable, and the kinetics of disease progression are difficult to predict. Genomic studies have shown that MDS is typically driven by a multistep somatic genetic process affecting a core set of genes. By definition, recurrent MDS driver mutations all drive clonal dominance, although they can have stereotyped positions in the clonal hierarchy or patterns of comutation association and exclusivity. Furthermore, environmental context, such as exposures to cytotoxic chemotherapy or the presence of germ-line predisposition, can influence disease pathogenesis and clinical outcomes. This review will address how an enhanced understanding of MDS genetics may enable refinement of current diagnostic schema, improve understanding of the pathogenesis of therapy-related MDS, and identify germ-line predispositions to development of MDS that are more common than recognized by standard clinical evaluation.

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.

RUNX1 deficiency (familial platelet disorder with predisposition to myeloid leukemia, FPDMM)

In this review, we discuss disease-causing alterations of RUNT-related transcription factor 1 (RUNX1), a master regulator of hematopoietic differentiation. Familial platelet disorder with predisposition to myeloid leukemia (FPDMM) typically presents with (1) mild to moderate thrombocytopenia with normal-sized platelets; (2) functional platelets defects leading to prolonged bleeding; and (3) an increased risk to develop myelodysplastic syndromes (MDS), acute myeloid leukemia (AML), or T-cell acute lymphoblastic leukemia (T-ALL). Hematological neoplasms in carriers of a germline RUNX1 mutation need additional secondary mutations or chromosome aberrations to develop. If a disease-causing mutation is known in the family, it is important to prevent hematopoietic stem cell transplantation from a sibling or other relative carrying the familial mutation. First experiments introducing a wild-type copy of RUNX1 into induce pluripotent stem cells (iPSC) lines from patients with FPDMM appear to demonstrate that by gene correction reversal of the phenotype may be possible.

Prognostic Mutations in Myelodysplastic Syndrome after Stem-Cell Transplantation

BACKGROUND

Genetic mutations drive the pathogenesis of the myelodysplastic syndrome (MDS) and are closely associated with clinical phenotype. Therefore, genetic mutations may predict clinical outcomes after allogeneic hematopoietic stem-cell transplantation.

METHODS

We performed targeted mutational analysis on samples obtained before transplantation from 1514 patients with MDS who were enrolled in the Center for International Blood and Marrow Transplant Research Repository between 2005 and 2014. We evaluated the association of mutations with transplantation outcomes, including overall survival, relapse, and death without relapse.

RESULTS

TP53 mutations were present in 19% of the patients and were associated with shorter survival and a shorter time to relapse than was the absence of TP53 mutations, after adjustment for significant clinical variables (P<0.001 for both comparisons). Among patients 40 years of age or older who did not have TP53 mutations, the presence of RAS pathway mutations was associated with shorter survival than was the absence of RAS pathway mutations (P=0.004), owing to a high risk of relapse, and the presence of JAK2 mutations was associated with shorter survival than was the absence of JAK2 mutations (P=0.001), owing to a high risk of death without relapse. The adverse prognostic effect of TP53 mutations was similar in patients who received reduced-intensity conditioning regimens and those who received myeloablative conditioning regimens. By contrast, the adverse effect of RAS pathway mutations on the risk of relapse, as compared with the absence of RAS pathway mutations, was evident only with reduced-intensity conditioning (P<0.001). In young adults, 4% of the patients had compound heterozygous mutations in the Shwachman-Diamond syndrome-associated SBDS gene with concurrent TP53 mutations and a poor prognosis. Mutations in the p53 regulator PPM1D were more common among patients with therapy-related MDS than those with primary MDS (15% vs. 3%, P<0.001).

CONCLUSIONS

Genetic profiling revealed that molecular subgroups of patients undergoing allogeneic hematopoietic stem-cell transplantation for MDS may inform prognostic stratification and the selection of conditioning regimen. (Funded by the Edward P. Evans Foundation and others.).

Introduction to cancer genetic susceptibility syndromes

The last 30 years have witnessed tremendous advances in our understanding of the cancer genetic susceptibility syndromes, including those that predispose to hematopoietic malignancies. The identification and characterization of families affected by these syndromes is enhancing our knowledge of the oncologic and nononcologic manifestations associated with predisposing germ line mutations and providing insights into the underlying disease mechanisms. Here, we provide an overview of the cancer genetic susceptibility syndromes, focusing on aspects relevant to the evaluation of patients with leukemia and lymphoma. Guidance is provided to facilitate recognition of these syndromes by hematologists/oncologists, including descriptions of the family history features, tumor genotype, and physical or developmental findings that should raise concern for an underlying cancer genetic syndrome. The clinical implications and management challenges associated with cancer susceptibility syndromes are also discussed.

Discussing and managing hematologic germ line variants

With the introduction of genomic technologies, more hereditary cancer syndromes with hematologic malignancies are being described. Up to 10% of hematologic malignancies in children and adults may be the result of an underlying inherited genetic risk. Managing these patients with hereditary hematologic malignancies, including familial leukemia, remains a clinical challenge because there is little information about these relatively rare disorders. This article covers some of the issues related to the diagnosis and interpretation of variants associated with hereditary hematologic malignancies, including the importance of an accurate family history in interpreting genetic variants associated with disease. The challenges of screening other family members and offering the most appropriate early malignancy detection is also discussed. We now have a good opportunity to better define hereditary cancer syndromes with associated hematologic malignancies and contribute to clinically effective guidelines.

Preleukemia: one name, many meanings

Definition of preleukemia has evolved. It was first used to describe the myelodysplastic syndrome (MDS) with a propensity to progress to acute myeloid leukemia (AML). Individuals with germline mutations of either RUNX1, CEBPA, or GATA2 can also be called as preleukemic because they have a markedly increased incidence of evolution into AML. Also, alkylating chemotherapy or radiation can cause MDS/preleukemia, which nearly always progress to AML. More recently, investigators noted that AML patients who achieved complete morphological remission after chemotherapy often have clonal hematopoiesis predominantly marked by either DNMT3A, TET2 or IDH1/2 mutations, which were also present at diagnosis of AML. This preleukemic clone represents involvement of an early hematopoietic stem cells, which is resistant to standard therapy. The same clonal hematopoietic mutations have been identified in older ‘normal' individuals who have a modest increased risk of developing frank AML. These individuals have occasionally been said, probably inappropriately, to have a preleukemia clone. Our evolving understanding of the term preleukemia has occurred by advancing technology including studies of X chromosome inactivation, cytogenetics and more recently deep nucleotide sequencing.

Discussing and managing hematologic germ line variants

With the introduction of genomic technologies, more hereditary cancer syndromes with hematologic malignancies are being described. Up to 10% of hematologic malignancies in children and adults may be the result of an underlying inherited genetic risk. Managing these patients with hereditary hematologic malignancies, including familial leukemia, remains a clinical challenge because there is little information about these relatively rare disorders. This article covers some of the issues related to the diagnosis and interpretation of variants associated with hereditary hematologic malignancies, including the importance of an accurate family history in interpreting genetic variants associated with disease. The challenges of screening other family members and offering the most appropriate early malignancy detection is also discussed. We now have a good opportunity to better define hereditary cancer syndromes with associated hematologic malignancies and contribute to clinically effective guidelines.

Evaluation of Patients and Families With Concern for Predispositions to Hematologic Malignancies Within the Hereditary Hematologic Malignancy Clinic (HHMC)

INTRODUCTION

Although multiple predispositions to hematologic malignancies exist, evaluations for hereditary cancer syndromes (HCS) are underperformed by most hematologist/oncologists. Criteria for initiating HCS evaluation are poorly defined, and results of genetic testing for hereditary hematologic malignancies have not been systematically reported.

PATIENTS AND METHODS

From April 2014 to August 2015, 67 patients were referred to the Hereditary Hematologic Malignancy Clinic (HHMC). Referral reasons included (1) bone marrow failure or myelodysplastic syndrome in patients ≤ 50 years, (2) evaluation for germ-line inheritance of identified RUNX1, GATA2, or CEBPA mutations on targeted next-generation sequencing panels, and (3) strong personal and/or family history of malignancy. Cultured skin fibroblasts were utilized for germ-line DNA in all patients with hematologic malignancy.

RESULTS

Eight patients (12%) were clinically diagnosed with a HCS: 4 patients with RUNX1-related familial platelet disorder (FPD)/acute myeloid leukemia (AML), and 1 patient each with dyskeratosis congenita, Fanconi anemia, germ-line DDX41, and Li-Fraumeni syndrome (LFS). Two patients with concern for FPD/AML and LFS, respectively, had RUNX1 and TP53 variants of unknown significance. Additionally, 4 patients with prior HCS diagnosis (1 LFS, 3 FPD/AML) were referred for further evaluation and surveillance.

CONCLUSION

In this HHMC-referred hematologic malignancy cohort, HCS was confirmed in 12 patients (18%). HCS identification provides insight for improved and individualized treatment, as well as screening/surveillance opportunities for family members. The HHMC has facilitated HCS diagnosis; with increased clinical awareness of hematologic malignancy predisposition syndromes, more patients who may benefit from evaluation can be identified. Mutation panels intended for prognostication may provide increased clinical suspicion for germ-line testing.

Myeloid Neoplasms with Germline Predisposition: A New Provisional Entity Within the World Health Organization Classification

The forthcoming update of the World Health Organization (WHO) classification of hematopoietic neoplasms will feature "Myeloid Neoplasms with Germline Predisposition" as a new provisional diagnostic entity. This designation will be applied to some cases of acute myeloid leukemia and myelodysplastic syndrome arising in the setting of constitutional mutations that render patients susceptible to the development of myeloid malignancies. For the diagnostic pathologist, recognizing these cases and confirming the diagnosis will demand a sophisticated grasp of clinical genetics and molecular techniques. This article presents a concise review of this new provisional WHO entity, including strategies for clinical practice.