New proposals of the WHO working group (2016) for the diagnosis of myelodysplastic syndromes (MDS): Characteristics of refined MDS types

MDS patient registries - achievements and challenges

Since the late 1980s, patient registries have played a pivotal role in the elucidation of rare diseases. For myelodysplastic syndromes (MDS), they revealed the disease actually to be diverse rather than rare. Registry data enabled the definition of various MDS subtypes and prognostic scores tailoring therapy. These classifications have been revised and refined several times, and the differential diagnosis of MDS has become increasingly complex. At the same time, the diagnosis has been made more commonly and no longer by specialized centers of expertise only. Consequently, several registries have collected data with different focuses and from different patient subpopulations. The current review presents three MDS registries and their rationale, scope, design, and achievements. All three complement each other and will remain a mainstay to advance the knowledge on MDS as well as to validate the outcomes of clinical trials. However, delineation of subtypes after the most recent WHO and IPC revisions, as well as the determination of the newest risk score M of the International Prognostic Scoring System (IPSS-M), no longer just shift cut-offs but are based on multivariate compilations of highly specific genetic information. This paradigm shift involves challenging registries with respect to the assignment of all patients for whom this information has not yet been available.

Significance of SF3B1 Mutations in Myeloid Neoplasms

Myelodysplastic neoplasm with low blasts and SF3B1 mutation (MDS-LB-SF3B1) has undergone significant classification changes in the past year with the publication of the 5th edition of the World Health Organization Classification of Tumors of Haematopoietic and Lymphoid Tissues and the International Consensus Classification. This article reviews the basic biology of SF3B1, iron metabolism, and dysfunction that leads to the formation of ring sideroblasts. It highlights neoplastic and non-neoplastic considerations to the differential diagnoses. Finally, a review on the evolution of the prognostic scoring system and treatment regimens that are available to patients with a diagnosis of MDS is presented.

Progress in construction of mouse models to investigate the pathogenesis and immune therapy of human hematological malignancy

Hematological malignancy is a disease arisen by complicate reasons that seriously endangers human health. The research on its pathogenesis and therapies depends on the usage of animal models. Conventional animal model cannot faithfully mirror some characteristics of human features due to the evolutionary divergence, whereas the mouse models hosting human hematological malignancy are more and more applied in basic as well as translational investigations in recent years. According to the construction methods, they can be divided into different types (e.g. cell-derived xenograft (CDX) and patient-derived xenograft model (PDX) model) that have diverse characteristics and application values. In addition, a variety of strategies have been developed to improve human hematological malignant cell engraftment and differentiation in vivo. Moreover, the humanized mouse model with both functional human immune system and autologous human hematological malignancy provides a unique tool for the evaluation of the efficacy of novel immunotherapeutic drugs/approaches. Herein, we first review the evolution of the mouse model of human hematological malignancy; Then, we analyze the characteristics of different types of models and summarize the ways to improve the models; Finally, the way and value of humanized mouse model of human immune system in the immunotherapy of human hematological malignancy are discussed.

Monocytosis at the time of diagnosis has a negative prognostic impact in myelodysplastic syndromes with less than 5% bone marrow blasts

The prognostic impact of monocytosis has not yet been determined in patients with myelodysplastic syndromes (MDS). We examined absolute monocyte counts in the peripheral blood at the time of diagnosis in 1949 patients with a bone marrow blast count < 5%, a condition we call MDS < EB1 (MDS with a blast percentage lower than that of MDS with excess blasts 1, according to the WHO classification). Monocytosis (> 600/µl) was associated with higher median hemoglobin, WBC, and ANC, and more favorable karyotype (p = .001). Nevertheless, monocytosis was associated with shorter overall survival (OS) (108 vs. 126 months, p = .002) and earlier transformation into AML (p < .001). In patients with sideroblastic phenotype, the percentage of ring sideroblasts significantly correlated with the monocyte count (p = .005), and OS was significantly shorter when monocytosis was documented (88 vs. 132 months, p = .004). The survival disadvantage of patients with MDS < EB1 and peripheral blood monocytosis suggests that these patients suffer from a CMML-like disease. Even though they are generally classified as MDS with persistent monocytosis, such patients should be considered candidates for therapeutic options employed in CMML.

The International Consensus Classification of myelodysplastic syndromes and related entities

The International Consensus Classification (ICC) of myeloid neoplasms and acute leukemia has updated the classification of myelodysplastic syndromes (MDSs) and placed MDS in a broader group of clonal cytopenias that includes clonal cytopenia of undetermined significance (CCUS) and related entities. Although subject to some interobserver variability and lack of specificity, morphologic dysplasia remains the main feature that distinguishes MDS from other clonal cytopenias and defines MDS as a hematologic malignancy. The ICC has introduced some changes in the definition of MDS whereby some cases categorized as MDS based on cytogenetic abnormalities are now classified as CCUS, while SF3B1 and multi-hit TP53 mutations are now considered to be MDS-defining in a cytopenic patient. The ICC has also recognized several cytogenetic and molecular abnormalities that reclassify some cases of MDS with excess blasts as acute myeloid leukemia (AML) and has introduced a new MDS/AML entity that encompasses cases with 10-19% blasts that lie on the continuum between MDS and AML. Two new genetically defined categories of MDS have been introduced: MDS with mutated SF3B1 and MDS with mutated TP53, the latter requiring bi-allelic aberrations in the TP53 gene. The entity MDS, unclassifiable has been eliminated. These changes have resulted in an overall simplification of the MDS classification scheme from 8 separate entities (including 1 that was genetically defined) in the revised 4th edition WHO classification to 7 separate entities (including 3 that are genetically defined) in the ICC.

Elucidating the Heterogeneity of Serum Metabolism in Patients with Myelodysplastic Syndrome and Acute Myeloid Leukemia by Raman Spectroscopy

Myelodysplastic syndrome (MDS) is difficult to diagnose and classify because it has the potential to evolve into acute myeloid leukemia (AML). Raman spectroscopy and orthogonal partial least squares discrimination analysis (OPLS-DA) are used to systematically analyze peripheral blood serum samples from 33 patients with MDS, 25 patients with AML, and 29 control volunteers to gain insight into the heterogeneity of serum metabolism in patients with MDS and AML. AML patients show unique serum spectral data compared to MDS patients with considerably greater peak intensities of collagen (859 and 1345 cm^-1) and carbohydrate (920 and 1123 cm^-1) compared to MDS patients. Screening and bioinformatics analysis of MDS- and AML-related genes based on the Gene Expression Omnibus (GEO) database shows that 1459 genes are differentially expressed, and the main signaling pathways are related to Th17 cell differentiation, pertussis, and cytokine receptor interaction. Statistical analysis of serological indexes related to glucose and lipid metabolism shows that patients with AML have increased serum triglyceride (TG) levels and decreased total protein levels. This study provides a spectral basis for the relationship between the massive serological data of patients and the typing of MDS and AML and provides important information for the rapid and early identification of MDS and AML.

Comparison of the revised 4th (2016) and 5th (2022) editions of the World Health Organization classification of myelodysplastic neoplasms

We used data from 852 consecutive subjects with myelodysplastic neoplasms (MDS) diagnosed according to the 2016 (revised 4th) World Health Organization (WHO) criteria to evaluate the 2022 (5th) edition WHO classification of MDS. 30 subjects previously classified as MDS with an NPM1 mutation were re-classified as acute myeloid leukaemia (AML). 9 subjects previously classified as MDS-U were re-classified to clonal cytopenia of undetermined significance (CCUS). The remaining 813 subjects were diagnosed as: MDS-5q (N = 11 [1%]), MDS-SF3B1 (N = 70 [9%]), MDS-biTP53 (N = 53 [7%]), MDS-LB (N = 293 [36%]), MDS-h (N = 80 [10%]), MDS-IB1 (N = 161 [20%]), MDS-IB2 (N = 103 [13%]) and MDS-f (N = 42 [5%]) and MDS-biTP53 (N = 53 [7%]). 34 of these subjects came from the 53 (64%) MDS-biTP53 previously diagnosed as MDS-EB. Median survival of subjects classified as MDS using the WHO 2022 criteria was 45 months (95% Confidence Interval [CI], 34, 56 months). Subjects re-classified as MDS-biTP53 and MDS-f had significantly briefer median survivals compared with other MDS sub-types (10 months, [8, 12 months] and 15 months [8, 23 months]). In conclusion, our analyses support the refinements made in the WHO 2022 proposal.

Assessing the Prognosis of Patients with Myelodysplastic Syndromes (MDS)

Prognostic stratification in patients with myelodysplastic syndrome (MDS) relies on a number of key factors. Combining such patient-related and disease-related prognostic parameters into useful assessment tools remains a challenge. The most widely used scoring systems include the international prognostic scoring system (IPSS), the revised IPSS (IPSS-R), the World Health Organization (WHO) Prognostic Scoring System (WPSS), and the new molecular IPSS (IPSS-M). Similar to the IPSS-R and the IPSS-M, the chronic myelomonocytic leukemia (CMML) prognostic scoring system (CPSS) and the CPSS molecular (CPSS-mol) are powerful and reliable prognostic tools that help to assess the individual prognosis of patients with CMML. The well-established prognostic assessment of MDS and CMML may be further augmented by additional disease-related parameters, such as somatic mutations, or patient-related factors, such as comorbidities. In this article, we briefly describe useful prognostic scoring systems for myelodysplastic syndromes and identify some open questions that require further investigation.

Iron overload-induced oxidative stress in myelodysplastic syndromes and its cellular sequelae

The myelodysplastic syndromes (MDS) are clonal hematopoietic stem cell disorders. MDS patients often require red blood cell transfusions, resulting in iron overload (IOL). IOL increases production of reactive oxygen species (ROS), oxygen free radicals. We review and illustrate how IOL-induced ROS influence cellular activities relevant to MDS pathophysiology. ROS damage lipids, nucleic acids in mitochondrial and nuclear DNA, structural proteins, transcription factors and enzymes. Cellular consequences include decreased metabolism and tissue and organ dysfunction. In hematopoietic stem cells (HSC), consequences of ROS include decreased glycolysis, shifting the cell from anaerobic to aerobic metabolism and causing HSC to exit the quiescent state, leading to HSC exhaustion or senescence. ROS oxidizes DNA bases, resulting in accumulation of mutations. Membrane oxidation alters fluidity and permeability. In summary, evidence indicates that IOL-induced ROS alters cellular signaling pathways resulting in toxicity to organs and hematopoietic cells, in keeping with adverse clinical outcomes in MDS.

Clinical, biological, and prognostic implications of SF3B1 co-occurrence mutations in very low/low- and intermediate-risk MDS patients

SF3B1 is a highly mutated gene in myelodysplastic syndrome (MDS) patients, related to a specific subtype and parameters of good prognosis in MDS without excess blasts. More than 40% of MDS patients carry at least two myeloid-related gene mutations but little is known about the impact of concurrent mutations on the outcome of MDS patients. In applying next-generation sequencing (NGS) with a 117 myeloid gene custom panel, we analyzed the co-occurrence of SF3B1 with other mutations to reveal their clinical, biological, and prognostic implications in very low/low- and intermediate-risk MDS patients. Mutations in addition to those of SF3B1 were present in 80.4% of patients (median of 2 additional mutations/patient, range 0-5). The most frequently mutated genes were as follows: TET2 (39.2%), DNMT3A (25.5%), SRSF2 (10.8%), CDH23 (5.9%), and ASXL1, CUX1, and KMT2D (4.9% each). The presence of at least two mutations concomitant with that of SF3B1 had an adverse impact on survival compared with those with the SF3B1 mutation and fewer than two additional mutations (median of 54 vs. 87 months, respectively: p = 0.007). The co-occurrence of SF3B1 mutations with specific genes is also linked to a dismal prognosis: SRSF2 mutations were associated with shorter overall survival (OS) than SRSF2wt (median, 27 vs. 75 months, respectively; p = 0.001), concomitant IDH2 mutations (median OS, 11 [mut] vs. 75 [wt] months; p = 0.001), BCOR mutations (median OS, 11 [mut] vs. 71 [wt] months; p = 0.036), and NUP98 and STAG2 mutations (median OS, 27 and 11 vs. 71 months, respectively; p = 0.008 and p = 0.002). Mutations in CHIP genes (TET2, DNMT3A) did not significantly affect the clinical features or outcome. Our results suggest that a more comprehensive NGS study in low-risk MDS SF3B1^mut patients is essential for a better prognostic evaluation.

Favorable prognostic phenotype in myelodysplastic syndrome with der(1;7)(q10;p10)

Unbalanced translocation der(1;7)(q10;p10) is a characteristic chromosomal abnormality in myelodysplastic syndrome (MDS). The current study revealed that among 13 MDS patients with der(1;7)(q10;p10), seven cases with no apparent dysplasia also had low numbers of myeloblasts in the bone marrow and a 3-year survival rate of 86%; in contrast, the remaining six cases had a 3-year survival rate of 0% (P = .003). It was therefore suggested that MDS patients with der(1;7)(q10;p10) are classified into a distinct group with a favorable prognosis and another distinct group with a very poor prognosis.

Deficiency and haploinsufficiency of histone macroH2A1.1 in mice recapitulate hematopoietic defects of human myelodysplastic syndrome

Background

Epigenetic regulation is important in hematopoiesis, but the involvement of histone variants is poorly understood. Myelodysplastic syndromes (MDS) are heterogeneous clonal hematopoietic stem cell (HSC) disorders characterized by ineffective hematopoiesis. MacroH2A1.1 is a histone H2A variant that negatively correlates with the self-renewal capacity of embryonic, adult, and cancer stem cells. MacroH2A1.1 is a target of the frequent U2AF1 S34F mutation in MDS. The role of macroH2A1.1 in hematopoiesis is unclear.

Results

MacroH2A1.1 mRNA levels are significantly decreased in patients with low-risk MDS presenting with chromosomal 5q deletion and myeloid cytopenias and tend to be decreased in MDS patients carrying the U2AF1 S34F mutation. Using an innovative mouse allele lacking the macroH2A1.1 alternatively spliced exon, we investigated whether macroH2A1.1 regulates HSC homeostasis and differentiation. The lack of macroH2A1.1 decreased while macroH2A1.1 haploinsufficiency increased HSC frequency upon irradiation. Moreover, bone marrow transplantation experiments showed that both deficiency and haploinsufficiency of macroH2A1.1 resulted in enhanced HSC differentiation along the myeloid lineage. Finally, RNA-sequencing analysis implicated macroH2A1.1-mediated regulation of ribosomal gene expression in HSC homeostasis.

Conclusions

Together, our findings suggest a new epigenetic process contributing to hematopoiesis regulation. By combining clinical data with a discrete mutant mouse model and in vitro studies of human and mouse cells, we identify macroH2A1.1 as a key player in the cellular and molecular features of MDS. These data justify the exploration of macroH2A1.1 and associated proteins as therapeutic targets in hematological malignancies.

Electronic supplementary material

The online version of this article (10.1186/s13148-019-0724-z) contains supplementary material, which is available to authorized users.

Delayed time from RBC transfusion dependence to first cardiac event in lower IPSS risk MDS patients receiving iron chelation therapy

Transfused MDS patients are at risk for iron overload (IOL). IOL may exacerbate congestive heart failure (CHF), coronary artery disease (CAD) and arrythmias (ARR). We retrospectively examined cardiac events (CE) in red blood cell (RBC) transfusion dependent (TD) lower IPSS risk MDS patients. Patients were censored at death or MDS progression. 151 MDS patients were lower IPSS risk and RBC TD. Median number of cardiac risk factors (RF) per patient was 1 (1-4). CE following RBC TD occurred in 48 (32%) and were: CHF, n = 20; CAD, n = 15; ARR, n = 11. In univariate analysis factors significant for time to (TT) CE were: age at 1st RBC transfusion; number of RBCU transfused while lower IPSS risk; received iron chelation therapy (ICT); MDS treatment received; and number of cardiac RF/patient (p ≤ 0.02). Receiving ICT remained significant for TTCE in multivariate analysis (p = 0.03). Median TTCE in patients not receiving and receiving ICT was 7.0 (0.1-65.0) and 20.0 (0.1-148.6) months, respectively (p = 0.02). For lower IPSS risk RBC transfusion dependent MDS patients, time to first cardiac event following RBC TD was significantly longer in patients receiving ICT. These results suggest ICT may delay cardiac events in transfused patients. The results should be confirmed in larger numbers in prospective analyses.

Routes of Clonal Evolution into Complex Karyotypes in Myelodysplastic Syndrome Patients with 5q Deletion

Myelodysplastic syndrome (MDS) can easily transform into acute myeloid leukemia (AML), a process which is often associated with clonal evolution and development of complex karyotypes. Deletion of 5q (del(5q)) is the most frequent aberration in complex karyotypes. This prompted us to analyze clonal evolution in MDS patients with del(5q). There were 1684 patients with low and intermediate-risk MDS and del(5q) with or without one additional cytogenetic abnormality, who were investigated cytogenetically in our department, involving standard karyotyping, fluorescence in situ hybridization (FISH) and multicolor FISH. We identified 134 patients (8%) with aspects of clonal evolution. There are two main routes of cytogenetic clonal evolution: a stepwise accumulation of cytogenetic events over time and a catastrophic event, which we defined as the occurrence of two or more aberrations present at the same time, leading to a sudden development of highly complex clones. Of the 134 patients, 61% underwent a stepwise accumulation of events whereas 39% displayed a catastrophic event. Patients with isolated del(5q) showed significantly more often a stepwise accumulation of events rather than a catastrophic event. The most frequent aberrations in the group of stepwise accumulation were trisomy 8 and trisomy 21 which were significantly more frequent in this group compared to the catastrophic event group. In the group with catastrophic events, del(7q)/-7 and del(17p)/-17 were the most common aberrations. A loss of 17p, containing the tumor suppressor gene TP53, was found significantly more frequent in this group compared to the group of stepwise accumulation. This leads to the assumption that the loss of TP53 is the driving force in patients with del(5q) who undergo a sudden catastrophic event and evolve into complex karyotypes.

Normal and pathological erythropoiesis in adults: from gene regulation to targeted treatment concepts

Pathological erythropoiesis with consequent anemia is a leading cause of symptomatic morbidity in internal medicine. The etiologies of anemia are complex and include reactive as well as neoplastic conditions. Clonal expansion of erythroid cells in the bone marrow may result in peripheral erythrocytosis and polycythemia but can also result in anemia when clonal cells are dysplastic and have a maturation arrest that leads to apoptosis and hinders migration, a constellation typically seen in the myelodysplastic syndromes. Rarely, clonal expansion of immature erythroid blasts results in a clinical picture resembling erythroid leukemia. Although several mechanisms underlying normal and abnormal erythropoiesis and the pathogenesis of related disorders have been deciphered in recent years, little is known about specific markers and targets through which prognosis and therapy could be improved in anemic or polycythemic patients. In order to discuss new markers, targets and novel therapeutic approaches in erythroid disorders and the related pathologies, a workshop was organized in Vienna in April 2017. The outcomes of this workshop are summarized in this review, which includes a discussion of new diagnostic and prognostic markers, the updated WHO classification, and an overview of new drugs used to stimulate or to interfere with erythropoiesis in various neoplastic and reactive conditions. The use and usefulness of established and novel erythropoiesis-stimulating agents for various indications, including myelodysplastic syndromes and other neoplasms, are also discussed.

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.

Iron overload in lower international prognostic scoring system risk patients with myelodysplastic syndrome receiving red blood cell transfusions: Relation to infections and possible benefit of iron chelation therapy

BACKGROUND

An increased incidence of infections and infectious mortality has been reported in myelodysplastic syndromes (MDS) patients receiving red blood cell (RBC) transfusions.

METHODS

We examined incidence of infections requiring antibiotics, antifungal or antiviral medications in transfused lower International Prognostic Scoring System (IPSS) risk MDS patients and whether this differed with iron chelation therapy (ICT).

RESULTS

138 transfused MDS patients were lower IPSS risk. 59 received ICT; median duration was 13 months. There was no significant difference between groups in neutrophil count at first RBC transfusion or first infection. Infections included: bacterial, n = 88; viral; fungal; and mycobacterial; n = 2 each. In ICT and non-ICT patients, respectively, infections were (number [%]): patients, 23 (40.0%) and 22 (27.8%); episodes (median [range]), 2 (1-6) and 2 (1-5); hospitalizations, 16 (27.1%) and 8 (10.1%); and deaths, 0 (0%) and 1 (1.3%), p = NS for all. Median overall survival (OS) from first RBC transfusion was superior in ICT patients, p = 0.01, and remained significant in a multivariate analysis (MVA), p = 0.003. Median time to first infection (TTI) was 27 and 7.8 months, respectively, p < 0.0001, and ICT remained significant for TTI in an MVA, p = 0.02, hazard ratio 0.3. For ICT patients with blast count <5%, TTI was significantly superior (p = 0.004).

CONCLUSIONS

In this retrospective analysis, for lower IPSS risk MDS patients receiving RBC transfusions, though number and type of infections were similar between groups and despite similar neutrophil counts, time to first infection was significantly longer in ICT patients (p < 0.0001). These results should be confirmed in larger, prospective analyses.

Proposed minimal diagnostic criteria for myelodysplastic syndromes (MDS) and potential pre-MDS conditions

Myelodysplastic syndromes (MDS) comprise a heterogeneous group of myeloid neoplasms characterized by peripheral cytopenia, dysplasia, and a variable clinical course with about 30% risk to transform to secondary acute myeloid leukemia (AML). In the past 15 years, diagnostic evaluations, prognostication, and treatment of MDS have improved substantially. However, with the discovery of molecular markers and advent of novel targeted therapies, new challenges have emerged in the complex field of MDS. For example, MDS-related molecular lesions may be detectable in healthy individuals and increase in prevalence with age. Other patients exhibit persistent cytopenia of unknown etiology without dysplasia. Although these conditions are potential pre-phases of MDS they may also transform into other bone marrow neoplasms. Recently identified molecular, cytogenetic, and flow-based parameters may add in the delineation and prognostication of these conditions. However, no generally accepted integrated classification and no related criteria are as yet available. In an attempt to address this challenge, an international consensus group discussed these issues in a working conference in July 2016. The outcomes of this conference are summarized in the present article which includes criteria and a proposal for the classification of pre-MDS conditions as well as updated minimal diagnostic criteria of MDS. Moreover, we propose diagnostic standards to delineate between ´normal´, pre-MDS, and MDS. These standards and criteria should facilitate diagnostic and prognostic evaluations in clinical studies as well as in clinical practice.