Recent developments in myelodysplastic syndromes

Inflamma-miRs Profile in Myelodysplastic Syndrome Patients

Etiological factors involved in myelodysplastic syndrome (MDS) include immunologic, oxidative stress and inflammatory factors, among others, and these are targets for microRNAs (miRNs). Here, we evaluated whether some miRNs may affect tumor development comparing untreated and 5-azacitidine (5-AZA) MDS-treated patients. Peripheral blood samples were collected from 20 controls and 24 MDS patients, and selected miRNs related to redox balance and inflammation (inflamma-miRs), including miR-18a, miR-21, miR-34a and miR-146a, were isolated and measured by quantitative real-time polymerase chain reaction (qRTPCR). A differential expression profile of miRNs was detected in untreated MDS patients and the 5-AZA group. Inflammation increases miRNs and, specifically, miR-18a, miR-21 and miR-34a were significantly overexpressed in untreated MDS, compared to controls. However, we did not observe any miRN profile alteration during the progression of the disease. On the other hand, 5-AZA treatment tends to restore miRN expression levels. Relating to prognostic risk factors, high-risk MDS groups (high Revised International Prognostic Scoring System (IPSS-R), high cytogenetic risk, high molecular risk (HMR) mutations) tended to be related with higher expression levels of miR-18a and miR-34a. Higher miRN expression is correlated with lower glutathione peroxidase activity, while they are related with a higher profile of pro-inflammatory cytokines (IL-2, IL-6, IL-8, TNF-α). Although our study was limited by the low number of MDS patients included, we identified miRN deregulation involved in MDS development that could regulate redox sensors and inflammatory responses. Finally, 5-AZA treatment is related with lower miRN expression levels in MDS patients.

Decitabine cytotoxicity is promoted by dCMP deaminase DCTD and mitigated by SUMO-dependent E3 ligase TOPORS

The nucleoside analogue decitabine (or 5-aza-dC) is used to treat several haematological cancers. Upon its triphosphorylation and incorporation into DNA, 5-aza-dC induces covalent DNA methyltransferase 1 DNA-protein crosslinks (DNMT1-DPCs), leading to DNA hypomethylation. However, 5-aza-dC's clinical outcomes vary, and relapse is common. Using genome-scale CRISPR/Cas9 screens, we map factors determining 5-aza-dC sensitivity. Unexpectedly, we find that loss of the dCMP deaminase DCTD causes 5-aza-dC resistance, suggesting that 5-aza-dUMP generation is cytotoxic. Combining results from a subsequent genetic screen in DCTD-deficient cells with the identification of the DNMT1-DPC-proximal proteome, we uncover the ubiquitin and SUMO1 E3 ligase, TOPORS, as a new DPC repair factor. TOPORS is recruited to SUMOylated DNMT1-DPCs and promotes their degradation. Our study suggests that 5-aza-dC-induced DPCs cause cytotoxicity when DPC repair is compromised, while cytotoxicity in wild-type cells arises from perturbed nucleotide metabolism, potentially laying the foundations for future identification of predictive biomarkers for decitabine treatment.

Transcription elongation defects link oncogenic SF3B1 mutations to targetable alterations in chromatin landscape

Transcription and splicing of pre-messenger RNA are closely coordinated, but how this functional coupling is disrupted in human diseases remains unexplored. Using isogenic cell lines, patient samples, and a mutant mouse model, we investigated how cancer-associated mutations in SF3B1 alter transcription. We found that these mutations reduce the elongation rate of RNA polymerase II (RNAPII) along gene bodies and its density at promoters. The elongation defect results from disrupted pre-spliceosome assembly due to impaired protein-protein interactions of mutant SF3B1. The decreased promoter-proximal RNAPII density reduces both chromatin accessibility and H3K4me3 marks at promoters. Through an unbiased screen, we identified epigenetic factors in the Sin3/HDAC/H3K4me pathway, which, when modulated, reverse both transcription and chromatin changes. Our findings reveal how splicing factor mutant states behave functionally as epigenetic disorders through impaired transcription-related changes to the chromatin landscape. We also present a rationale for targeting the Sin3/HDAC complex as a therapeutic strategy.

The Challenge for a Correct Diagnosis of Refractory Thrombocytopenia: ITP or MDS with Isolated Thrombocytopenia?

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by isolated thrombocytopenia. It is diagnosed in patients with a platelet count below 100,000 per cubic millimeter in whom other causes of thrombocytopenia have been ruled out, and its diagnosis is generally one of exclusion. Clinical manifestations of patients may vary from asymptomatic disease to mild mucocutaneous or life-threatening bleeding. Glucocorticoids are used as first-line treatment for ITP, while other second-line medications, mainly thrombopoietin-receptor agonists (TPO-RA) and rituximab, are given to patients in whom ITP does not remit, or relapses soon after glucocorticoid treatment. Refractoriness of ITP strongly questions its diagnosis and necessitates a thorough clinical and laboratory work-up to decide whether that is the case of refractory ITP or a misdiagnosis. The aim of this review is to summarize the conditions associated with isolated thrombocytopenia and highlight the characteristics of confusing cases. Even though the case of a myelodysplastic syndrome presented with isolated thrombocytopenia (MDS-IT) is relatively rare and not well-established in the literature, it constitutes one of the most predominant misdiagnoses of refractory ITP. MDS-IT patients are thought to present with multilineage dysplasia, normal karyotype and low risk prognostic score, based on IPSS-R. It has been shown that a significant proportion of MDS-IT patients are misdiagnosed as having the more common ITP. Therefore, it is crucial that in confusing cases of persistent thrombocytopenia a detailed diagnostic work-up is applied-including evaluation of peripheral-blood smear, bone marrow examination and cytogenetic testing-to avoid unnecessary therapy delay.

Luspatercept in low-risk myelodysplastic syndromes: a paradigm shift in treatment strategies

INTRODUCTION

In patients with myelodysplastic syndromes (MDS), anemia is prevalent affecting 80%-85% of low-risk (LR-MDS) patients, with 40% eventually requiring red blood cell (RBC) transfusions. Except forlenalidomide, exclusively approved for those with deletion of chromosome 5q,erythropoiesis-stimulating agents (ESAs) are the primary treatment choice for low-risk patients. Those unresponsive to ESAs face limited alternatives, eventually necessitating long-term RBC transfusions, leading to secondary iron overload and adversely affecting quality of life (QoL).

AREA COVERED

Luspatercept is a pioneering erythroid maturation agent. It received approval by both the European Medicines Agency (EMA) and the Food and Drug Administration (FDA) for treating adults experiencing transfusion-dependent anemia associated with LR-MDS or β-thalassemia. Recently, the FDA approved luspatercept as first- line therapy in patients with very low- to intermediate-risk MDS who require RBC transfusions and have not previously received ESAs. This review summarizes the historical impact of luspatercept intreating LR-MDS unresponsive to ESAs and illustrates its potential benefit asfrontline therapy in MDS and its employment in patients with myelofibrosis-induced anemia.

EXPERT OPINION

Luspatercept has revolutionized the therapeutic paradigm of LR-MDS, for which there was a limited therapeutic arsenal, especially in the setting of patients who did not respond or fail after ESA treatment.

The Role of Hepcidin in Myelodysplastic Syndromes (MDS): A Systematic Review of Observational Studies

Iron overload emerges as a serious complication in myelodysplastic syndromes (MDS), particularly associated with frequent transfusions during the course of the disease. The discovery and description of hepcidin's mechanisms of action have contributed to a deeper understanding of iron metabolism. The existing literature reports a potential role of hepcidin in MDS, yet these data are fragmented and presented in an unstructured, somewhat chaotic manner. Hence, to address the existing data, we performed a systematic review of observational studies examining hepcidin levels in MDS. An extensive review of three bibliographic databases (Pubmed, Web of Science, and Scopus) enabled us to identify 12 observational studies. These studies focused primarily on adult patients with low-risk MDS who underwent transfusions and chelation therapy. An in-depth analysis of these manuscripts led to four main conclusions: (1) although high serum hepcidin levels are associated with MDS, most studies generally have not found a significant difference in these levels between patients and healthy individuals; (2) serum hepcidin levels are specific to MDS type; (3) serum hepcidin levels in MDS are strongly associated with transfusions and the genetic status of patients; and (4) high-risk MDS is associated with high serum hepcidin levels. While we have furnished a comprehensive summary of the significance of hepcidin in MDS, there are still gaps that future research should address. This pertains primarily to the capacity of hepcidin in predicting adverse outcomes for MDS patients and evaluating the efficacy of chelation therapy or the need for transfusion.

Ultrasensitive chimerism enhances measurable residual disease testing after allogeneic hematopoietic cell transplantation

Increasing mixed chimerism (reemerging recipient cells) after allogeneic hematopoietic cell transplant (allo-HCT) can indicate relapse, the leading factor determining mortality in blood malignancies. Most clinical chimerism tests have limited sensitivity and are primarily designed to monitor engraftment. We developed a panel of quantitative polymerase chain reaction assays using TaqMan chemistry capable of quantifying chimerism in the order of 1 in a million. At such analytic sensitivity, we hypothesized that it could inform on relapse risk. As a proof-of-concept, we applied our panel to a retrospective cohort of patients with acute leukemia who underwent allo-HCT with known outcomes. Recipient cells in bone marrow aspirates (BMAs) remained detectable in 97.8% of tested samples. Absolute recipient chimerism proportions and rates at which these proportions increased in BMAs in the first 540 days after allo-HCT were associated with relapse. Detectable measurable residual disease (MRD) via flow cytometry in BMAs after allo-HCT showed limited correlation with relapse. This correlation noticeably strengthened when combined with increased recipient chimerism in BMAs, demonstrating the ability of our ultrasensitive chimerism assay to augment MRD data. Our technology reveals an underappreciated usefulness of clinical chimerism. Used side by side with MRD assays, it promises to improve identification of patients with the highest risk of disease reoccurrence for a chance of early intervention.

Emerging Insights into Molecular Mechanisms of Inflammation in Myelodysplastic Syndromes

Inflammation impacts human hematopoiesis across physiologic and pathologic conditions, as signals derived from the bone marrow microenvironment, such as pro-inflammatory cytokines and chemokines, have been shown to alter hematopoietic stem cell (HSCs) homeostasis. Dysregulated inflammation can skew HSC fate-related decisions, leading to aberrant hematopoiesis and potentially contributing to the pathogenesis of hematological disorders such as myelodysplastic syndromes (MDS). Recently, emerging studies have used single-cell sequencing and muti-omic approaches to investigate HSC cellular heterogeneity and gene expression in normal hematopoiesis as well as in myeloid malignancies. This review summarizes recent reports mechanistically dissecting the role of inflammatory signaling and innate immune response activation due to MDS progression. Furthermore, we highlight the growing importance of using multi-omic techniques, such as single-cell profiling and deconvolution methods, to unravel MDSs' heterogeneity. These approaches have provided valuable insights into the patterns of clonal evolution that drive MDS progression and have elucidated the impact of inflammation on the composition of the bone marrow immune microenvironment in MDS.

Diamond-Blackfan anemia in adults: In pursuit of a common approach for a rare disease

Diamond-Blackfan anemia (DBA) is a rare bone marrow failure syndrome, usually caused by loss-of function variants in genes encoding ribosomal proteins. The hallmarks of DBA are anemia, congenital anomalies and cancer predisposition. Although DBA usually presents in childhood, the prevalence in later life is increasing due to an expanding repertoire of implicated genes, improvements in genetic diagnosis and increasing life expectancy. Adult patients uniquely suffer the manifestations of end-organ damage caused by the disease and its treatment, and transition to adulthood poses specific issues in disease management. To standardize and optimize care for this rare disease, in this review we provide updated guidance on the diagnosis and management of DBA, with a specific focus on older adolescents and adults. Recommendations are based upon published literature and our pooled clinical experience from three centres in the United Kingdom (U·K.). Uniquely we have also solicited and incorporated the views of affected families, represented by the independent patient organization, DBA U.K.

CCRL2 affects the sensitivity of myelodysplastic syndrome and secondary acute myeloid leukemia cells to azacitidine

Better understanding of the biology of resistance to DNA methyltransferase (DNMT) inhibitors is required to identify therapies that can improve their efficacy for patients with high-risk myelodysplastic syndrome (MDS). CCRL2 is an atypical chemokine receptor that is upregulated in CD34+ cells from MDS patients and induces proliferation of MDS and secondary acute myeloid leukemia (sAML) cells. In this study, we evaluated any role that CCRL2 may have in the regulation of pathways associated with poor response or resistance to DNMT inhibitors. We found that CCRL2 knockdown in TF-1 cells downregulated DNA methylation and PRC2 activity pathways and increased DNMT suppression by azacitidine in MDS/sAML cell lines (MDS92, MDS-L and TF-1). Consistently, CCRL2 deletion increased the sensitivity of these cells to azacitidine in vitro and the efficacy of azacitidine in an MDS-L xenograft model. Furthermore, CCRL2 overexpression in MDS-L and TF-1 cells decreased their sensitivity to azacitidine. Finally, CCRL2 levels were higher in CD34+ cells from MDS and MDS/myeloproliferative neoplasm patients with poor response to DNMT inhibitors. In conclusion, we demonstrated that CCRL2 modulates epigenetic regulatory pathways, particularly DNMT levels, and affects the sensitivity of MDS/sAML cells to azacitidine. These results support CCRL2 targeting as having therapeutic potential in MDS/sAML.

Significant improvement of bone marrow-derived MSC expansion from MDS patients by defined xeno-free medium

BACKGROUND

Robust and reliable in vitro and in vivo models of primary cells are necessary to study the pathomechanisms of Myelodysplastic Neoplasms (MDS) and identify novel therapeutic strategies. MDS-derived hematopoietic stem and progenitor cells (HSPCs) are reliant on the support of bone marrow (BM) derived mesenchymal stroma cells (MSCs). Therefore, isolation and expansion of MCSs are essential for successfully modeling this disease. For the clinical use of healthy MSCs isolated from human BM, umbilical cord blood or adipose tissue, several studies showed that xeno-free (XF) culture conditions resulted in superior growth kinetics compared to MSCs cultured in the presence of fetal bovine serum (FBS). In this present study, we investigate, whether the replacement of a commercially available MSC expansion medium containing FBS with a XF medium is beneficial for the expansion of MSCs derived from BM of MDS patients which are often difficult to cultivate.

METHODS

MSCs isolated from BM of MDS patients were cultured and expanded in MSC expansion medium with FBS or XF supplement. Subsequently, the impact of culture media on growth kinetics, morphology, immunophenotype, clonogenic potential, differentiation capacity, gene expression profiles and ability to engraft in immunodeficient mouse models was evaluated.

RESULTS

Significant higher cell numbers with an increase in clonogenic potential were observed during culture of MDS MSCs with XF medium compared to medium containing FBS. Differential gene expression showed an increase in transcripts associated with MSC stemness after expansion with XF. Furthermore, immunophenotypes of the MSCs and their ability to differentiate into osteoblasts, adipocytes or chondroblasts remained stable. MSCs expanded with XF media were similarly supportive for creating MDS xenografts in vivo as MSCs expanded with FBS.

CONCLUSION

Our data indicate that with XF media, higher cell numbers of MDS MSCs can be obtained with overall improved characteristics in in vitro and in vivo experimental models.

Vitamin B5 and succinyl-CoA improve ineffective erythropoiesis in SF3B1-mutated myelodysplasia

Patients with myelodysplastic syndrome and ring sideroblasts (MDS-RS) present with symptomatic anemia due to ineffective erythropoiesis that impedes their quality of life and increases morbidity. More than 80% of patients with MDS-RS harbor splicing factor 3B subunit 1 (SF3B1) mutations, the founder aberration driving MDS-RS disease. Here, we report how mis-splicing of coenzyme A synthase (COASY), induced by mutations in SF3B1, affects heme biosynthesis and erythropoiesis. Our data revealed that COASY was up-regulated during normal erythroid differentiation, and its silencing prevented the formation of erythroid colonies, impeded erythroid differentiation, and precluded heme accumulation. In patients with MDS-RS, loss of protein due to COASY mis-splicing led to depletion of both CoA and succinyl-CoA. Supplementation with COASY substrate (vitamin B5) rescued CoA and succinyl-CoA concentrations in SF3B1mut cells and mended erythropoiesis differentiation defects in MDS-RS primary patient cells. Our findings reveal a key role of the COASY pathway in erythroid maturation and identify upstream and downstream metabolites of COASY as a potential treatment for anemia in patients with MDS-RS.

Exploiting the ubiquitin system in myeloid malignancies. From basic research to drug discovery in MDS and AML

The ubiquitin-proteasome system is the crucial homeostatic mechanism responsible for the degradation and turnover of proteins. As such, alterations at this level are often associated with oncogenic processes, either through accumulation of undegraded pathway effectors or, conversely, excessive degradation of tumor-suppressing factors. Therefore, investigation of the ubiquitin- proteasome system has gained much attraction in recent years, especially in the context of hematological malignancies, giving rise to efficient therapeutics such as bortezomib for multiple myeloma. Current investigations are now focused on manipulating protein degradation via fine-tuning of the ubiquitination process through inhibition of deubiquitinating enzymes or development of PROTAC systems for stimulation of ubiquitination and protein degradation. On the other hand, the efficiency of Thalidomide derivates in myelodysplastic syndromes (MDS), such as Lenalidomide, acted as the starting point for the development of targeted leukemia-associated protein degradation molecules. These novel molecules display high efficiency in overcoming the limitations of current therapeutic regimens, such as refractory diseases. Therefore, in this manuscript we will address the therapeutic opportunities and strategies based on the ubiquitin-proteasome system, ranging from the modulation of deubiquitinating enzymes and, conversely, describing the potential of modern targeted protein degrading molecules and their progress into clinical implementation.

Historical expectations with DNA methyltransferase inhibitor monotherapy in MDS: when is combination therapy truly "promising"?

DNA methyltransferase inhibitors (DNMTIs) for patients with higher risk myelodysplastic syndromes (HR-MDS) have low complete remission rates and are not curative. Early DNMTI combination clinical trials in HR-MDS are often termed "promising," but many randomized trials subsequently failed to show benefit. Clearer understanding of when a combination is likely to improve upon DNMTI monotherapy would inform randomized studies. We reviewed MDS azacitidine or decitabine monotherapy studies. We collected baseline demographics including International Prognostic Scoring System (IPSS) risk, DNMTI, disease characteristics; and response variables including survival and marrow and hematologic responses. Aggregate estimates across studies were calculated using meta-analyses techniques. Using a binomial design, we estimated the necessary operating characteristics to design a phase 2 study showing improved efficacy of a combination over monotherapy. Among 1908 patients, the overall response rate (ORR) was 24% (n = 464; 95% confidence interval [CI], 0.22-0.26): 267 complete response (CR, 14%), 68 partial response (4%), and 129 marrow complete remission (7%). Among 1604 patients for whom a hematologic response was reported, 476 (30%; 95% CI, 0.27-0.32) reported hematologic improvement (HI). More patients treated with azacitidine achieved HI (38%; 95% CI, 0.35-0.41) compared with decitabine (15%; 95% CI, 0.13-0.19), whereas the marrow ORR rate was higher with decitabine (29%; 95% CI, 0.26-0.33) compared with azacitidine (21%; 95% CI, 0.19-0.23). CR rates were similar between DNMTIs: 13% with azacitidine and 16% with decitabine. Variables that influence MDS response include the specific DNMTI backbone and the distribution of IPSS risk of patients enrolled on a trial. Considering these factors can help identify which early combination approaches are worth assessing in larger randomized trials.

Gut Microbiome and Plasma Metabolomic Analysis in Patients with Myelodysplastic Syndrome

Myelodysplastic syndrome (MDS) is a heterogeneous group of clonal hematopoietic stem cell disorders. Studies have shown the involvement of an abnormal immune system in MDS pathogenesis. The gut microbiota are known to influence host immunity and metabolism, thereby contributing to the development of hematopoietic diseases. In this study, we performed gut microbiome and plasma metabolomic analyses in patients with MDS and healthy controls. We found that patients with MDS had a different gut microbial composition compared to controls. The gut microbiota in MDS patients showed a continuous evolutionary relationship from the phylum to the species level. At the species level, the abundance of Haemophilus parainfluenzae, Streptococcus luteciae, Clostridium citroniae, and Gemmiger formicilis increased, while that of Prevotella copri decreased in MDS patients compared to controls. Moreover, abundance of bacterial genera correlated with the percentage of lymphocyte subsets in patients with MDS. Metabolomic analysis showed that the concentrations of hypoxanthine and pyroglutamic acid were increased, while that of 3a,7a-dihydroxy-5b-cholestan was decreased in MDS patients compared to controls. In conclusion, gut microbiome and plasma metabolomics are altered in patients with MDS, which may be involved in the immunopathogenesis of the disease.

Effect of 5-Azacitidine Treatment on Redox Status and Inflammatory Condition in MDS Patients

This study focused on the impact of the treatment with the hypomethylating agent 5-azacitidine on the redox status and inflammation in 24 MDS patients. Clinical and genetic features of MDS patients were recorded, and peripheral blood samples were used to determine the activity of the endogenous antioxidant defense system (superoxide dismutase, SOD; catalase, CAT; glutathion peroxidase, GPx; and reductase, GRd, activities), markers of oxidative damage (lipid peroxidation, LPO, and advanced oxidation protein products, AOPP). Moreover, pro-inflammatory cytokines and plasma nitrite plus nitrate levels as markers of inflammation, as well as CoQ10 plasma levels, were also measured. Globally, MDS patients showed less redox status in terms of a reduction in the GSSG/GSH ratio and in the LPO levels, as well as increased CAT activity compared with healthy subjects, with no changes in SOD, GPx, and GRd activities, or AOPP levels. When analyzing the evolution from early to advanced stages of the disease, we found that the GPx activity, GSSG/GSH ratio, LPO, and AOPP increased, with a reduction in CAT. GPx changes were related to the presence of risk factors such as high-risk IPSS-R or mutational score. Moreover, there was an increase in IL-2, IL-6, IL-8, and TNF-α plasma levels, with a further increase of IL-2 and IL-10 from early to advanced stages of the disease. However, we did not observe any association between inflammation and oxidative stress. Finally, 5-azacitidine treatment generated oxidative stress in MDS patients, without affecting inflammation levels, suggesting that oxidative status and inflammation are two independent processes.

The European Medicines Agency Review of Luspatercept for the Treatment of Adult Patients With Transfusion-dependent Anemia Caused by Low-risk Myelodysplastic Syndromes With Ring Sideroblasts or Beta-thalassemia

Luspatercept is a recombinant fusion protein that selectively binds to ligands belonging to the transforming growth factor-beta superfamily, resulting in erythroid maturation and differentiation. On June 25, 2020, a marketing authorization valid through the European Union (EU) was issued for luspatercept for the treatment of adult patients with transfusion-dependent anemia caused by very low-, low-, and intermediate-risk myelodysplastic syndromes (MDS) with ring sideroblasts, or those with transfusion-dependent beta thalassemia (BT). Luspatercept was evaluated in 2 separate phase 3, double-blind, placebo-controlled multicentre trials. The primary endpoints of these trials were the percentage of patients achieving transfusion independence over ≥8 weeks or longer for patients with MDS, and the percentage of patients achieving a ≥33% reduction in transfusion burden from baseline to week 13–24 for patients with BT. In the MDS trial, the percentage of responders was 37.91% versus 13.16%, P < 0.0001, for patients receiving luspatercept versus placebo, respectively. In the BT trial, the percentage of responders was 21.4% versus 4.5% (P < 0.0001) for luspatercept versus placebo, respectively. Treatment with luspatercept led to similar incidences of adverse events (AEs), but higher incidences of grade ≥3 AEs and serious AEs compared to placebo. The most frequently reported treatment-emergent AEs (≥15%) in the pooled luspatercept group were headache; back pain, bone pain, and arthralgia; diarrhea; fatigue; pyrexia; and cough. The aim of this article is to summarize the scientific review of the application, which led to the regulatory approval in the EU.

Myelodysplastic Syndromes in the Postgenomic Era and Future Perspectives for Precision Medicine

Simple Summary

With demographic ageing, improved cancer survivorship and increased diagnostic sensitivity, incident cases of patients with Myelodysplastic Syndromes (MDS) are continuously rising, leading to a relevant impact on health care resources. Disease heterogeneity and various comorbidities are challenges for the management of the generally elderly patients. Therefore, experienced physicians and multidisciplinary teams should be involved in the establishment of the correct diagnosis, risk-assessment and personalized treatment plan. Next-generation sequencing allows for early detection of clonal hematopoiesis and monitoring of clonal evolution, but also poses new challenges for its appropriate use. At present, allogeneic hematopoietic stem cell transplantation remains the only curative treatment option for a minority of fit MDS patients. All others receive palliative treatment and will eventually progress, having an unmet need for novel therapies. Targeting compounds are in prospect for precision medicine, however, abrogation of clonal evolution to acute myeloid leukemia remains actually out of reach.

Abstract

Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal disorders caused by sequential accumulation of somatic driver mutations in hematopoietic stem and progenitor cells (HSPCs). MDS is characterized by ineffective hematopoiesis with cytopenia, dysplasia, inflammation, and a variable risk of transformation into secondary acute myeloid leukemia. The advent of next-generation sequencing has revolutionized our understanding of the genetic basis of the disease. Nevertheless, the biology of clonal evolution remains poorly understood, and the stochastic genetic drift with sequential accumulation of genetic hits in HSPCs is individual, highly dynamic and hardly predictable. These continuously moving genetic targets pose substantial challenges for the implementation of precision medicine, which aims to maximize efficacy with minimal toxicity of treatments. In the current postgenomic era, allogeneic hematopoietic stem cell transplantation remains the only curative option for younger and fit MDS patients. For all unfit patients, regeneration of HSPCs stays out of reach and all available therapies remain palliative, which will eventually lead to refractoriness and progression. In this review, we summarize the recent advances in our understanding of MDS pathophysiology and its impact on diagnosis, risk-assessment and disease monitoring. Moreover, we present ongoing clinical trials with targeting compounds and highlight future perspectives for precision medicine.

Novel spontaneous myelodysplastic syndrome mouse model

Background

Myelodysplastic syndrome (MDS) is a group of disorders involving hemopoietic dysfunction leading to leukemia. Although recently progress has been made in identifying underlying genetic mutations, many questions still remain. Animal models of MDS have been produced by introduction of specific mutations. However, there is no spontaneous mouse model of MDS, and an animal model to simulate natural MDS pathogenesis is urgently needed.

Methods

In characterizing the genetically diverse mouse strains of the Collaborative Cross (CC) we observed that one, designated JUN, had abnormal hematological traits. This strain was thus further analyzed for phenotypic and pathological identification, comparing the changes in each cell population in peripheral blood and in bone marrow.

Results

In a specific-pathogen free environment, mice of the JUN strain are relatively thin, with healthy appearance. However, in a conventional environment, they become lethargic, develop wrinkled yellow hair, have loose and light stools, and are prone to infections. We found that the mice were cytopenic, which was due to abnormal differentiation of multipotent bone marrow progenitor cells. These are common characteristics of MDS.

Conclusions

A mouse strain, JUN, was found displaying spontaneous myelodysplastic syndrome. This strain has the advantage over existing models in that it develops MDS spontaneously and is more similar to human MDS than genetically modified mouse models. JUN mice will be an important tool for pathogenesis research of MDS and for evaluation of new drugs and treatments.

Oligomonocytic and overt chronic myelomonocytic leukemia show similar clinical, genomic, and immunophenotypic features

Oligomonocytic chronic myelomonocytic leukemia (OM-CMML) is defined as those myelodysplastic syndromes (MDSs) or myelodysplastic/myeloproliferative neoplasms, unclassifiable with relative monocytosis (≥10% monocytes) and a monocyte count of 0.5 to <1 × 109/L. These patients show clinical and genomic features similar to those of overt chronic myelomonocytic leukemia (CMML), although most of them are currently categorized as MDS, according to the World Health Organization 2017 classification. We analyzed the clinicopathologic features of 40 patients with OM-CMML with well-annotated immunophenotypic and molecular data and compared them to those of 56 patients with overt CMML. We found similar clinical, morphological, and cytogenetic features. In addition, OM-CMML mirrored the well-known complex molecular profile of CMML, except for the presence of a lower percentage of RAS pathway mutations. In this regard, of the different genes assessed, only CBL was found to be mutated at a significantly lower frequency. Likewise, the OM-CMML immunophenotypic profile, assessed by the presence of >94% classical monocytes (MO1s) and CD56 and/or CD2 positivity in peripheral blood monocytes, was similar to overt CMML. The MO1 percentage >94% method showed high accuracy for predicting CMML diagnosis (sensitivity, 90.7%; specificity, 92.2%), even when considering OM-CMML as a subtype of CMML (sensitivity, 84.9%; specificity, 92.1%) in our series of 233 patients (39 OM-CMML, 54 CMML, 23 MDS, and 15 myeloproliferative neoplasms with monocytosis and 102 reactive monocytosis). These results support the consideration of OM-CMML as a distinctive subtype of CMML.

Diagnosis and prognosis are supported by integrated assessment of next-generation sequencing in chronic myeloid malignancies. A real-life study

Next-generation sequencing (NGS) is used to investigate the presence of somatic mutations. The utility of incorporating routine sequencing to guide diagnosis and therapeutic decisions remains unclear. We report the findings of an observational, multicenter study that aimed to assess the impact of somatic mutation testing by NGS in a reallife setting of chronic myeloid malignancies. A total of 177 patients were enrolled, partitioned into two overlapping groups. In group A (n=94), the indication was to search for clonal hematopoiesis, in a context of suspected myelodysplastic syndrome or myeloproliferative neoplasia. In group B (n=95), the theranostic impact of somatic mutations was studied. A panel of 34 genes was used on DNA extracted from blood or bone marrow samples. Within group A, the detection of clonal hematopoiesis supported the diagnosis of chronic myeloid malignancies for 31 patients while the absence of clonal hematopoiesis ruled out the suspected diagnosis in 47 patients. Within group B, NGS identified prognostically relevant somatic mutations in 32 patients, which had a therapeutic impact in 18 cases. By determining the presence or absence of somatic mutations, the application of NGS in daily practice was found to be useful for an integrated final diagnosis in 83% of the patients. Moreover, the search for somatic mutations had a prognostic impact that led to treatment modification in 19% of the cases. This study outlines the fact that adequate implementation of new investigations may have a significant positive medico-economic impact by enabling appropriate management of patients.

Summary of animal models of myelodysplastic syndrome

Myelodysplastic syndrome (MDS) is a malignant tumor of the hematological system characterized by long-term, progressive refractory hemocytopenia. In addition, the risk of leukemia is high, and once it develops, the course of acute leukemia is short with poor curative effect. Animal models are powerful tools for studying human diseases and are highly effective preclinical platforms. Animal models of MDS can accurately show genetic aberrations and hematopoietic clone phenotypes with similar cellular features (such as impaired differentiation and increased apoptosis), and symptoms can be used to assess existing treatments. Animal models are also helpful for understanding the pathogenesis of MDS and its relationship with acute leukemia, which helps with the identification of candidate genes related to the MDS phenotype. This review summarizes the current status of animal models used to research myelodysplastic syndrome (MDS).

Applications of next-generation sequencing in hematologic malignancies

In the last decade, next-generation sequencing (NGS) has rapidly progressed from a research method to a core component of standard-of-care clinical testing. In oncology, tumor sequencing provides a critical tool to detect somatic driver mutations that not only characterize disease but also impact therapeutic decision-making. Here, we review the important role of NGS in the evaluation of hematopoietic neoplasms. We discusstechnical and practical considerations relevant in somatic mutation testing, emphasizing issues unique to blood cancers. Then, we describe how NGS data is being used to facilitate diagnosis, inform prognosis, guide therapy selection, and even monitor disease. This broad overview highlights the transformative impacts NGS data provides throughout the clinical course of patients with hematologic malignancies.

Arsenic Dispensing Powder Promotes Erythropoiesis in Myelodysplastic Syndromes via Downregulation of HIF1A and Upregulation of GATA Factors

Traditional Chinese Medicine (TCM) is a practical medicine based on thousands of years of medical practice in China. Arsenic dispensing powder (ADP) has been used as a treatment for MDS patients with a superior efficacy on anemia at Xiyuan Hospital of China Academy of Chinese Medical Sciences. In this study, we retrospectively analyzed MDS patients that received ADP treatment in the past 9 years and confirmed that ADP improves patients' anemia and prolongs overall survival in intermediate-risk MDS patients. Then, we used the MDS transgenic mice model and cell line to explore the drug mechanism. In normal and MDS cells, ADP does not show cellular toxicity but promotes differentiation. In mouse MDS models, we observed that ADP showed significant efficacy on promoting erythropoiesis. In the BFU-E and CFU-E assays, ADP could promote erythropoiesis not only in normal clones but also in MDS clones. Mechanistically, we found that ADP could downregulate HIF1A in MDS clones through upregulation of VHL, P53 and MDM2, which is involved in two parallel pathways to downregulate HIF1A. We also confirmed that ADP upregulates GATA factors in normal clones. Thus, our clinical and experimental studies indicate that ADP is a promising drug to promote erythropoiesis in both MDS and normal clones with a superior outcome than current regular therapies. ADP promotes erythropoiesis in myelodysplastic syndromes via downregulation of HIF1A and upregulation of GATA factors.

An IDH1-vitamin C crosstalk drives human erythroid development by inhibiting pro-oxidant mitochondrial metabolism

The metabolic changes controlling the stepwise differentiation of hematopoietic stem and progenitor cells (HSPCs) to mature erythrocytes are poorly understood. Here, we show that HSPC development to an erythroid-committed proerythroblast results in augmented glutaminolysis, generating alpha-ketoglutarate (αKG) and driving mitochondrial oxidative phosphorylation (OXPHOS). However, sequential late-stage erythropoiesis is dependent on decreasing αKG-driven OXPHOS, and we find that isocitrate dehydrogenase 1 (IDH1) plays a central role in this process. IDH1 downregulation augments mitochondrial oxidation of αKG and inhibits reticulocyte generation. Furthermore, IDH1 knockdown results in the generation of multinucleated erythroblasts, a morphological abnormality characteristic of myelodysplastic syndrome and congenital dyserythropoietic anemia. We identify vitamin C homeostasis as a critical regulator of ineffective erythropoiesis; oxidized ascorbate increases mitochondrial superoxide and significantly exacerbates the abnormal erythroblast phenotype of IDH1-downregulated progenitors, whereas vitamin C, scavenging reactive oxygen species (ROS) and reprogramming mitochondrial metabolism, rescues erythropoiesis. Thus, an IDH1-vitamin C crosstalk controls terminal steps of human erythroid differentiation.

Identification of miR-320 family members as potential diagnostic and prognostic biomarkers in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis and the abnormal differentiation of hematopoietic stem cells. An increasing number of researches have demonstrated that microRNAs play crucial roles in the pathogenesis of myelodysplastic syndromes. Herein, we aimed to identify novel potential microRNAs bound up with the diagnosis and prognosis of MDS. MiRNA microarray analysis was used to screen deregulated microRNAs in the bone marrow of MDS patients. qRT-PCR was employed to confirm the microarray results. All members of miR-320 family (miR-320a, miR-320b, miR-320c, miR-320d, and miR-320e) were significantly increased in MDS patients compared to normal control. Although we found no correlation between miR-320 family and most clinical characteristics, high miR-320c and miR-320d expression seemed to be associated with high numbers of bone marrow (BM) blasts and worse karyotype. High expression of all the members of the miR-320 family seemed to be associated with a high prognostic score based on International Prognostic Scoring System (IPSS). The areas under the miR-320 family member ROC curves were 0.9037 (P < 0.0001), 0.7515 (P = 0.0002), 0.9647 (P < 0.0001), 0.8064 (P < 0.0001) and 0.9019 (P < 0.0001). Regarding Kaplan-Meier analysis, high miR-320c and miR-320d expression were related to shorter overall survival (OS). Moreover, multivariate analysis revealed the independent prognostic value of miR-320d for OS in MDS. The expression of miR-320 family members was up-regulated in MDS, and miR-320 family members could serve as candidate diagnostic biomarkers for MDS. High expression of miR-320d was an independent prognostic factor for OS in MDS.

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.

Higher-risk myelodysplastic syndromes with del(5q): does the del(5q) matter?

Introduction: Myelodysplastic Syndrome (MDS) represents a group of cancers characterized by abnormal blood cell formation and maturation, leading to various degrees of cytopenias and potential transformation to acute myeloid leukemia. Deletion of the long arm of chromosome 5 (del(5q)) is the most common clonal chromosomal anomaly in MDS, yet the population in this disease subtype is quite heterogeneous. This manuscript analyzes literature on high-risk MDS with del(5q) abnormalities.Areas covered: The paper will review outcomes with lenalidomide among high-risk MDS patients with del(5q). It will discuss the implications of harboring TP53 gene mutations, and share the data for allogeneic hematopoietic stem cell transplantations in this setting. Finally, the report evaluates the risk of disease progression in these patients.Expert commentary: Improved characterization of MDS has enhanced our understanding of patients with anomalies involving del(5q). Emerging literature is exploring combination therapy beyond lenalidomide, and next-generation sequencing may identify secondary mutations that could be an additional avenue for treatment.

Expression Profiles of DNA Methylation and Demethylation Machinery Components in Pediatric Myelodysplastic Syndrome: Clinical Implications

Purpose

The aim of this study was to analyse the expression profiles of DNMT1, DNMT3A, DNMT3B (components of DNA methylation machinery), TET2 and APOBEC3B (components of DNA demethylation machinery) in pediatric MDS patients and investigate their associations with MDS subtypes, cytogenetics, evolution to acute myeloid leukemia (AML) and p15^INK4B methylation level.

Patients and Methods

The expressions of DNMT1, DNMT3A, DNMT3B, TET2, and APOBEC3B were evaluated in 39 pediatric MDS patients by real-time quantitative PCR (qPCR). The quantification of p15^INK4B methylation levels (MtL) was performed in 20 pediatric MDS patients by pyrosequencing. Mann–Whitney test was used to evaluate possible differences between the expression levels of selected in patients and donors, according to MDS subtypes, karyotypes, evolution to AML and p15^INK4B MtL. The correlations between the expression levels of the different genes were assessed by Spearman rank correlation coefficient.

Results

We found that DNMTs expression levels were higher in pediatric MDS compared to donors [DNMT1 (p<0.03), DNMT3A (p<0.03), DNMT3B (p<0.02)]. TET2 and APOBEC3B expression levels did not show a statistically significant difference between pediatric patients and donors. Considering MDS subtypes, patients at initial stage presented DNMT1 overexpression (p<0.01), while DNMT3A (p<0.02) and DNMT3B (p<0.007) were overexpressed in advanced subtypes. TET2 and APOBEC3B expression did not differ in MDS subtypes. DNMT1 (p<0.03), DNMT3B (p<0.03), and APOBEC3B (p<0.04) expression was higher in patients with normal karyotypes, while patients with abnormal karyotypes showed higher DNMT3A expression (p<0.03). Karyotypes had no association with TET2 expression. DNMTs overexpression was observed in patients who showed disease evolution. A positive correlation was found between DNMTs expression and between APOBEC3B and DNMT3A/DNMT3B. However, TET2 expression was not correlated with DNMTs or APOBEC3B. p15^INK4B MtL was higher in pediatric MDS patients compared with donors (p<0.03) and its hypermethylation was associated with increased DNMT1 expression (p<0.009).

Conclusion

Our results suggest that the overexpression of DNMTs and an imbalance between the expressions of the DNA methylation/demethylation machinery components play an important role in MDS development and evolution to AML. These results have clinical implications indicating the importance of DNMTs inhibitors for preventing or delaying the progression to leukemia in pediatric MDS patients.

Copper and Zinc Levels in Myelodysplastic Syndrome Patients versus Healthy Subjects

Background:

Myelodysplastic syndrome (MDS) is a heterogeneous hematological disease and certain serum factors are assumed to be involved in its pathogenesis and progression. Given this, our aim was to comparatively investigate the copper, zinc, and iron levels in MDS patients and healthy individuals.

Methods:

This case-control study was conducted on 31 patients with MDS (according to the WHO criteria after investigating laboratory tests such as peripheral blood smear and bone marrow aspiration) attending Bahonar Hospital, Kerman, Iran, and 31 healthy subjects from 2016 to 2018. The levels of copper, ceruloplasmin, zinc, ferritin, and iron were compared between the two groups.

Results:

Among the MDS patients, five individuals (16.13%) had low serum copper level (mean: 67.8 ± 4.35 µg/dl). Serum copper level was 111.3 ± 27.7 and 138.3 ± 26.6 in case and control groups, respectively (P = 0.0001). The serum zinc level and bone marrow iron level were also significantly different between the two groups (P < 0.05).

Conclusion:

Overall, it can be concluded that because only a small proportion of the MDS patients enrolled in this study were found to have lower copper levels compared with the MDS patients population, further studies with a larger sample size and also clinical trials in MDS patients with serum zinc, and copper deficiency are recommended, and post-treatment hematological reassessment would also be beneficial to achieving more definitive results.

Tumor genetic alterations and features of the immune microenvironment drive myelodysplastic syndrome escape and progression

The transformation and progression of myelodysplastic syndromes (MDS) to secondary acute myeloid leukemia (sAML) involve genetic, epigenetic, and microenvironmental factors. Driver mutations have emerged as valuable markers for defining risk groups and as candidates for targeted treatment approaches in MDS. It is also evident that the risk of transformation to sAML is increased by evasion of adaptive immune surveillance. This study was designed to explore the immune microenvironment, immunogenic tumor-intrinsic mechanisms (HLA and PD-L1 expression), and tumor genetic features (somatic mutations and altered karyotypes) in MDS patients and to determine their influence on the progression of the disease. We detected major alterations of the immune microenvironment in MDS patients, with a reduced count of CD4⁺ T cells, a more frequent presence of markers related to T cell exhaustion, a more frequent presence of myeloid-derived suppressor cells (MDSCs), and changes in the functional phenotype of NK cells. HLA Class I (HLA-I) expression was normally expressed in CD34⁺ blasts and during myeloid differentiation. Only two out of thirty-six patients with homozygosity for HLA-C groups acquired complete copy-neutral loss of heterozygosity in the HLA region. PD-L1 expression on the leukemic clone was also increased in MDS patients. Finally, no interplay was observed between the anti-tumor immune microenvironment and mutational genomic features. In summary, extrinsic and intrinsic immunological factors might severely impair immune surveillance and contribute to clonal immune escape. Genomic alterations appear to make an independent contribution to the clonal evolution and progression of MDS.

Metformin inhibits cell proliferation in SKM-1 cells via AMPK-mediated cell cycle arrest

Metformin, a widely used antidiabetic drug, has previously been demonstrated to exert anti-cancer effects in certain hematological malignancies, but its effects on the transformation of myelodysplastic syndromes to acute myeloid leukemia (AML-MDS) remain unclear. The present study aimed to investigate the effects of metformin on SKM-1 cells (an AML-MDS cell line) and its underlying mechanisms. SKM-1 cells were treated with different concentrations of metformin. Cell proliferation was assayed by CCK-8. Apoptosis and cell cycle phases were detected by flow cytometry, while cell cycle related proteins and AMPK were tested by Western blot. SKM-1 cells were transfected with LV-AMPKα1-RNAi to reduce the expression of AMPK. Metformin inhibited cell proliferation in a dose and time dependent manner by inducing G0/G1 phase arrest rather than apoptosis induction. Metformin promoted the expression of p-AMPK, P53, P21^CIP1 and P27^KIP1, while inhibited the expression of CDK4 and CyclinD1. AMPK knockdown attenuated the effects of metformin on SKM-1 cells. These findings suggested that metformin inhibited proliferation of SKM-1 cells, potentially through an AMPK-mediated cell cycle arrest.

The evolving role of next generation sequencing in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are clonal haematological disorders characterized by haematopoietic cell dysplasia, peripheral blood cytopenias, and a predisposition for developing acute myeloid leukaemia (AML). Cytogenetics have historically been important in diagnosis and prognosis in MDS, but the growing accessibility of next generation sequencing (NGS) has led to growing research in the roles of molecular genetic variation on clinical decision-making in these disorders. Multiple genes have been previously studied and found to be associated with specific outcomes or disease types within MDS and knowledge of mutations in these genes provides insight into previously defined MDS subtypes. Knowledge of these mutations also informs development of novel therapies in the treatment of MDS. The precise role of NGS in the diagnosis, prognosis and monitoring of MDS remains unclear but the improvements in NGS technology and accessibility affords clinicians an additional practice tool to provide the best care for patients.

The efficacy and toxicity of the CHG priming regimen (low-dose cytarabine, homoharringtonine, and G-CSF) in higher risk MDS patients relapsed or refractory to decitabine

PURPOSE

Myelodysplastic syndromes (MDSs) refractory or relapsed after hypomethylating agents (HMAs) remain a therapeutic challenge. The CHG regimen has been demonstrated to be effective in initially treating higher risk MDS. The current study evaluated the efficacy and toxicity of the CHG regimen in patients who were resistant to decitabine.

METHODS

Patients with higher risk MDS relapsed or refractory to decitabine were enrolled in this study. Each patient received the CHG regimen (cytarabine (25 mg/day, days 1-14) and homoharringtonine (1 mg/day, days 1-14) intravenously with G-CSF (300 μg/day) subcutaneously from day 0 until neutrophil count recovery to 2.0 × 10⁹ cells/L). Next gene sequencing with a 31-gene panel was carried out in patients.

RESULTS

Thirty-three patients were enrolled, including 12 relapsed and 21 refractory cases. The overall response rate (ORR) was 39.4% (13 of 33), with 9 (27.3%) achieving complete remission (CR), 2 having marrow CR (mCR), and 2 achieving partial remission (PR). The CR rate was higher in patients harboring fewer gene mutations (0-1) (55.6%) than in those with more gene mutations (> 1) (12.5%) (p = 0.021). The median overall survival (OS) of the 33 patients was 7.0 months. Patients who achieved a response had significantly longer survival times than were found in those without a response (21.0 M vs. 4.0 M, p < 0.0001). The regimen was endurable for most of the patients.

CONCLUSIONS

The CHG priming regimen provided a safe and effective salvage regimen for higher risk MDS patients who were resistant to decitabine. Further studies involving larger samples will be needed. Clinical trial No. ChiCTR-ONC-11001501.

Myeloid maturation potentiates STAT3-mediated atypical IFN-γ signaling and upregulation of PD-1 ligands in AML and MDS

Interferon (IFN)-γ is the major mediator of anti-tumor immune responses; nevertheless, cancer cells use intrigue strategies to alter IFN-γ signaling and avoid elimination. Understanding the immune regulatory mechanisms employed by acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) cells upon exposure to IFN-γ is critical for development of immunotherapy and checkpoint blockade therapy approaches. This study aims to explore the influence of myeloid maturation on IFN-γ-induced PD-L1 and PD-L2 expression and on pro-leukemogenic transcription factor STAT3 signaling in AML and MDS. Stimulation of myeloid blasts’ maturation by all-trans retinoic acid (ATRA) or 1α,25-dihydroxyvitamin D3 (vitamin D) increased the CD11b⁺ fraction that expressed PD-1 ligands in response to IFN-γ. Intriguingly, STAT3 pathway was potently induced by IFN-γ and strengthened upon prolonged exposure. Nonetheless, STAT3-mediated atypical IFN-γ signaling appeared as a negligible factor for PD-L1 and PD-L2 expression. These negative influences of IFN-γ could be alleviated by a small-molecule inhibitor of STAT3, stattic, which also inhibited the upregulation of PD-L1. In conclusion, induction of myeloid maturation enhances the responsiveness of AML and MDS cells to IFN-γ. However, these malignant myeloid cells can exploit both STAT3 pathway and PD-1 ligands to survive IFN-γ-mediated immunity and maintain secondary immune resistance.

Factors predicting early mortality after new diagnosis of myelodysplastic syndrome: A population-based study

OBJECTIVE

Little prospective data regarding factors determining patient outcomes in myelodysplastic syndromes (MDS) are available. To establish features of early mortality in MDS, we compare characteristics of patients dying within 1 year of diagnosis with those surviving longer.

METHODS

We prospectively enrolled adults with a new MDS diagnosis in a population-based case-control study. Logistic regression was used to calculate odds ratios and 95% confidence intervals for potential predictors of early mortality. Subgroup analyses were conducted within the following groups: high-/very-high-risk IPSS-R; very-low-/low-/intermediate-risk IPSS-R; treated patients; and supportive care only patients.

RESULTS

We observed early mortality in those with abnormal cytogenetics (OR: 3.36, 95% CI: 1.52-7.46), three or greater cytogenetic abnormalities (OR: 3.48, 95% CI: 1.51-7.99), treatment at a community medical center (versus academic) (OR: 2.55, 95% CI: 1.18-5.47), and with 2-3 concurrent medical comorbidities (OR: 2.14, 95% CI: 1.08-4.22). Similarly, in subgroup analyses, abnormal cytogenetics remained the main predictor of early mortality.

CONCLUSION

Complex cytogenetics and prognostic risk category have been associated with early mortality without intervention. Our data confirm these associations in a large, prospectively followed cohort and highlight the significance of cytogenetic abnormalities and complexity regardless of IPSS-R risk categorization or treatment.

Myelodysplastic Syndrome related alterations of MAPK signaling in the bone marrow of experimental mice including stem/progenitor compartment

Myelodysplastic syndrome is considered globally as heterogenous group of neoplasm which often proclaims leukemic progression. The heterogeneity is reflected not only in clinical manifestations of the disease but also in salient causes of disease development. In spite of multiple therapeutic modalities, shortfall towards treatment of this disorder still persists. The focal point of tussle suggested toward defects, which are not confined to any unifying cellular signalling. The pathobiology of the disease often experiences an intriguing paradox involving 'hyperproliferative bone marrow with pancytopenic peripheral blood'. In our present study we have reported about MAPK signaling in the hematopoietic stem progenitor compartmental (HSPC) dysregulation during the course of alkylator(ENU) induced myelodysplasia. The phospho-protein status of RTK's(FLT3, PDGFR, EGFR) were markedly increased that activated MAPK signaling proteins which finally executed their tasks by transcription of c-Myc and Rb leading to uncontrolled cellular proliferation, simultaneously the activated c-Jun revealed stress related apoptosis. Altogether, the role of activated MAPK signaling in the HSPC's may have led to hyperproliferation and concurrent enhanced apoptosis of abnormal cells which gradually headed towards premalignant transformations during the course of disease. The phenotypic expression of the HSPC markers CD 150 and CD 90 also established a mechanistic correlation with MAPK signalling alterations and overall scenario.

Comparative assessment of conventional chromosomal analysis and fluorescence in situ hybridization in the evaluation of suspected myelodysplastic syndromes: A single institution experience

Background:

Myelodysplastic syndromes (MDSs) are a heterogeneous group of clonal hematopoietic neoplasms, roughly half of which harbor cytogenetic abnormalities with diagnostic, prognostic, and therapeutic significance. Fluorescence in situ hybridization (FISH) for the most commonly seen abnormalities (5/5q, –7/7q, +8, and –20/20q–) is routinely performed alongside conventional cytogenetics (CC) in the evaluation of suspected MDS despite conflicting reports of its relative contribution compared to CC alone.

Objectives:

To assess the additional diagnostic and prognostic value of performing concurrent FISH versus CC alone in cases of suspected MDS.

Materials and Methods:

A total of 127 bone marrow samples submitted to our cytogenetic laboratory with a presumptive diagnosis of MDS were evaluated by concurrent CC and an MDS FISH panel.

Results:

CC was used as the gold standard method with 100% sensitivity in detecting suspected MDS-associated cytogenetic abnormalities. FISH alone had a sensitivity of 76%, whereas CC alone achieved a sensitivity of 97%. The addition of FISH did not change the diagnosis nor change the Revised International Prognostic Scoring System score in any patient. Moreover, in 12 cases identified as positive by both CC and FISH, CC identified multiple chromosomal aberrations of clinical significance not interrogated by the FISH probe panel.

Conclusion:

CC alone is sufficiently sensitive in detecting suspected MDS-associated cytogenetic abnormalities that influence clinical decision-making. Routine FISH testing does not provide a significant increase in test sensitivity when an adequate karyotype is obtained. Therefore, FISH testing is best reserved for suspected MDS cases lacking sufficient metaphases.

Clinical outcome of patients diagnosed with myelodysplastic syndrome-unclassifiable (MDS-U): single center experience

Myelodysplastic syndrome unclassifiable (MDS-U) is a small subtype of myelodysplastic syndromes (MDS). However, rare literature exists in terms of natural progression and clinical outcome of patients with MDS-U. In the present study, we investigated the characteristics and the clinical outcomes of patients categorized as MDS-U based on 2008 World Health Organization criteria (WHO) in a single center comparing to other MDS groups. Out of eight hundred and two patients who met WHO criteria for MDS at our institution, ninety patients (11%) were initially classified as MDS-U. Upon pathological review, only half of the cases were confirmed to be MDS-U. With follow up, half of the MDS-U cases were reclassified to another subtype. We found neither significant difference in median overall survival nor in risk of transformation to acute myeloid leukemia when comparing MDS-U to other MDS groups. Additional larger studies are needed to confirm our results.

Evaluation of SF3B1 Mutation Screening by High-Resolution Melting Analysis and its Clinical Utility for Myelodysplastic Syndrome with Ring Sideroblasts at the Point of Diagnosis

Background

SF3B1 (splicing factor 3B subunit-1) somatic mutation is specifically detected in myelodysplastic syndrome (MDS) with ring sideroblasts (MDS-RS). We investigated the sensitivity and utility of SF3B1 mutation analysis as a clinical laboratory test.

Method

Detection limit for SF3B1 mutations by high-resolution melting (HRM) analysis was investigated by plasmid mixture. In 67 MDS patients, we examined the association between SF3B1 mutation and prognostic evaluation using the Revised International Prognostic Scoring System and revalidated MDS classifications based on the revised 4th edition of the WHO classification.

Results

HRM analysis enabled mutation detection in the 12.5% SF3B1 mutant alleles. SF3B1 mutation was detected in 9 cases, mostly in the low-risk group. Cases of MDS with ring sideroblasts unrelated to SF3B1 mutation were detected in the high-risk group. Two cases were reclassified as MDS-RS after detecting SF3B1 mutation.

Conclusions

SF3B1 mutation analysis as an initial screening at diagnosis increases the accuracy of prognostic prediction and disease classification.

Genomic loss of HLA alleles may affect the clinical outcome in low-risk myelodysplastic syndrome patients

The Revised International Prognostic Score and some somatic mutations in myelodysplastic syndrome (MDS) are independently associated with transformation to acute myeloid leukemia (AML). Immunity has also been implicated in the pathogenesis of MDS, although the underlying mechanism remains unclear. We performed a SNP array on chromosome 6 in CD34⁺ purified blasts from 19 patients diagnosed with advanced MDS and 8 patients with other myeloid malignancies to evaluate the presence of loss of heterozygosity (LOH) in HLA and its impact on disease progression. Three patients had acquired copy-neutral LOH (CN-LOH) on 6p arms, which may disrupt antigen presentation and act as a mechanism for immune system evasion. Interestingly, these patients had previously been classified at low risk of AML progression, and the poor outcome cannot be explained by the acquisition of adverse mutations. LOH HLA was not detected in the remaining 24 patients, who all had adverse risk factors. In summary, the clinical outcome of patients with advanced MDS might be influenced by HLA allelic loss, wich allows subclonal expansions to evade cytotoxic-T and NK cell attack. CN-LOH HLA may therefore be a factor favoring MDS progression to AML independently of the somatic tumor mutation load.

Low clinical trial accrual of patients with myelodysplastic syndromes: Causes and potential solutions

Despite few effective therapies, only a small percentage of patients diagnosed with myelodysplastic syndromes (MDS) in the United States are enrolled in prospective, interventional clinical trials. MDS-specific barriers to trial accrual include a high frequency of elderly patients with comorbid conditions, atypical disease features and uncertainty regarding the diagnosis (because other nonclonal processes also can cause dysplasia and cytopenias), a history of another nonmyeloid neoplasm resulting in therapy-related MDS, rapid disease recurrence after allogeneic stem cell transplantation, and an arbitrary division between MDS and acute myeloid leukemia. In addition, barriers to accrual that are common to other oncology populations, such as difficulty traveling to clinical trial enrollment sites and narrow trial eligibility criteria, also prevent patients with MDS from enrolling in studies. Collectively these barriers must be assessed systematically, and creative solutions are needed to improve outcomes for this needy patient population.

Evaluation of bone marrow microenvironment could change how myelodysplastic syndromes are diagnosed and treated

Myelodysplastic syndromes are a heterogeneous group of clonal hematopoietic disorders. However, the therapies used against the hematopoietic stem cells clones have limited efficacy; they slow the evolution toward acute myeloid leukemia rather than stop clonal evolution and eradicate the disease. The progress made in recent years regarding the role of the bone marrow microenvironment in disease evolution may contribute to progress in this area. This review presents the recent updates on the role of the bone marrow microenvironment in myelodysplastic syndromes pathogenesis and tries to find answers regarding how this information could improve myelodysplastic syndromes diagnosis and therapy.

Impact of lenalidomide use among non-transfusion dependent patients with myelodysplastic syndromes

Chemotherapies approved for defined subgroups promise personalized oncologic care, but their off-label impact is unclear. Lenalidomide is approved for lower-risk, transfusion-dependent (TD) myelodysplastic syndromes (MDS) with del(5q), but frequently used in MDS outside this indication. We characterized lenalidomide use and outcomes among non-TD patients with MDS. Patients 65 or older diagnosed with MDS between 2007 and 2013 were identified using SEER; linked Medicare claims were evaluated for transfusions, lenalidomide use, and incident toxicities. TD was ≥2 transfusion episodes within an 8-week period; responses were transfusion independence (TI) and ≥50% transfusion reduction (minor response). We compared overall survival for non-TD patients receiving lenalidomide versus those not receiving lenalidomide, matched on disease and patient characteristics. We identified 676 patients who had received lenalidomide, including 275 (40.7%) TD and 401 (59.3%) non-TD; 18.5% (125/676) had zero claims for RBC transfusion prior to receiving lenalidomide. Incident toxicities among patients prescribed lenalidomide were similar in TD and non-TD groups, except incident thromboembolic events were higher among non-TD patients (10.8% vs. 6.0%, P = .04). Comparing 191 non-TD patients receiving lenalidomide within 6 months of MDS diagnosis to risk-matched MDS controls, lenalidomide was not associated with improved OS (P = .78). Among TD patients (n = 275), 31% achieved TI, and 30% achieved minor hematologic response, with a median time to TI of 4.1 weeks. In conclusion, we confirmed the benefit of lenalidomide among TD patients with MDS; however, many non-TD patients also received lenalidomide. These patients experienced accompanying toxicity without evidence of benefit in terms of transfusion needs or overall survival.

The prognostic significance of global aberrant alternative splicing in patients with myelodysplastic syndrome

Aberrant alternative splicing (AS) is a hallmark of cancer development. However, there are limited data regarding its clinical implications in myelodysplastic syndrome (MDS). In this study, we performed an in-depth analysis of global AS in 176 primary MDS patients with 20 normal marrow transplant donors as reference. We found that 26.9% of the expressed genes genome-wide were aberrantly spliced in MDS patients compared with normal donors. These aberrant AS genes were related to pathways involved in cell proliferation, cell adhesion and protein degradation. A higher degree of global aberrant AS was associated with male gender and U2AF1 mutation, and predicted shorter overall survival and time to leukemic change. Moreover, it was an independent unfavorable prognostic factor irrespective of age, revised international prognostic scoring system (IPSS-R) risk, and mutations in SRSF2, ZRSR2, ASXL1, TP53, and EZH2. With LASSO-Cox regression method, we constructed a simple prognosis prediction model composed of 13 aberrant AS genes, and demonstrated that it could well stratify MDS patients into distinct risk groups. To our knowledge, this is the first report demonstrating significant prognostic impacts of aberrant splicing on MDS patients. Further prospective studies in larger cohorts are needed to confirm our observations.