Myelodysplastic Syndromes: Diagnosis and Treatment

Communication Strategies of Transplant Hematologists in High-Risk Decision-Making Conversations

PURPOSE

Shared decision making (SDM) is essential to empower patients with blood cancers to make goal-concordant decisions about allogeneic hematopoietic cell transplantation. This study characterizes communication strategies used by hematologists to discuss treatment options and facilitate SDM with patients in this high-risk, high-reward setting.

METHODS AND MATERIALS

We recruited US hematologists who routinely perform allogeneic hematopoietic cell transplant through email. Participants conducted up to an hour-long video-recorded encounter with an actor portraying a 67-year-old man with recently diagnosed high-risk myelodysplastic syndrome. We transcribed and qualitatively analyzed video-recorded data.

RESULTS

The mean age of participants (N = 37) was 44 years, 65% male, and 68% White. Many hematologists included similar key points in this initial consultation, although varied in how much detail they provided. Their discussion of treatment options included transplant and chemotherapy and less commonly supportive care or clinical trials. They often emphasized transplant's potential for cure, discussed transplant chronologically from pretransplant considerations through the post-transplant course, and outlined risks, complications, and major outcomes. Hematologists referred to several elements that formed the basis of treatment decision making. The strength of their treatment recommendations ranged from strong recommendations for transplant or chemotherapy to deferrals pending more information. Hematologists also varied in the extent to which they indicated the decision was physician-driven, patient-led, or shared.

CONCLUSION

The transplant decision-making discussion is complex. Identification of similar content areas used by hematologists can be used as the basis for a communication tool to help hematologists discuss allogeneic hematopoietic cell transplant with patients.

Myelodysplastic Neoplasms (MDS) with Ring Sideroblasts or SF3B1 Mutations: The Improved Clinical Utility of World Health Organization and International Consensus Classification 2022 Definitions, a Single-Centre Retrospective Chart Review

Myelodysplastic neoplasms (MDS) with ring sideroblasts (RS) are diagnosed via bone marrow aspiration in the presence of either (i) ≥15% RS or (ii) 5-14% RS and an SF3B1 mutation. In the MEDALIST trial and in an interim analysis of the COMMANDS trial, lower-risk MDS-RS patients had decreased transfusion dependency with luspatercept treatment. A total of 6817 patients with suspected hematologic malignancies underwent molecular testing using a next-generation-sequencing-based genetic assay and 395 MDS patients, seen at our centre from 1 January 2018 to 31 May 2023, were reviewed. Of these, we identified 39 evaluable patients as having lower-risk MDS with SF3B1 mutations: there were 20 (51.3%) males and 19 (48.7%) females, with a median age of 77 years (range of 57 to 92). Nineteen (48.7%) patients had an isolated SF3B1 mutation with a mean variant allele frequency of 35.2% +/- 8.1%, ranging from 7.4% to 46.0%. There were 29 (74.4%) patients with ≥15% RS, 6 (15.4%) with 5 to 14% RS, one (2.6%) with 1% RS, and 3 (7.7%) with no RS. Our study suggests that a quarter of patients would be missed based on the morphologic criterion of only using RS greater than 15% and supports the revised 2022 definitions of the World Health Organization (WHO) and International Consensus Classification (ICC), which shift toward molecularly defined subtypes of MDS and appropriate testing.

Infectious Complications in Patients with Myelodysplastic Syndromes: A Report from the Düsseldorf MDS Registry

Despite notable advancements in infection prevention and treatment, individuals with hematologic malignancies still face the persistent threat of frequent and life-threatening complications. Those undergoing chemotherapy or other disease-modifying therapies are particularly vulnerable to developing infectious complications, increasing the risk of mortality. Myelodysplastic syndromes (MDS) predominantly affect the elderly, with the incidence rising with age and peaking at around 70 years. Patients with MDS commonly present with unexplained low blood-cell counts, primarily anemia, and often experience varying degrees of neutropenia as the disease progresses. In our subsequent retrospective study involving 1593 patients from the Düsseldorf MDS Registry, we aimed at outlining the incidence of infections in MDS patients and identifying factors contributing to heightened susceptibility to infectious complications in this population.

Phase Ib study of sabatolimab (MBG453), a novel immunotherapy targeting TIM-3 antibody, in combination with decitabine or azacitidine in high- or very high-risk myelodysplastic syndromes

The safety and efficacy of sabatolimab, a novel immunotherapy targeting T-cell immunoglobulin domain and mucin domain-3 (TIM-3), was assessed in combination with hypomethylating agents (HMAs) in patients with HMA-naive revised International Prognostic System Score (IPSS-R) high- or very high-risk myelodysplastic syndromes (HR/vHR-MDS) or chronic myelomonocytic leukemia (CMML). Sabatolimab + HMA had a safety profile similar to that reported for HMA alone and demonstrated durable clinical responses in patients with HR/vHR-MDS. These results support the ongoing evaluation of sabatolimab-based combination therapy in MDS, CMML, and acute myeloid leukemia.

Recent advances in the application of induced pluripotent stem cell technology to the study of myeloid malignancies

Acquired myeloid malignancies are a spectrum of clonal disorders known to be caused by sequential acquisition of genetic lesions in hematopoietic stem and progenitor cells, leading to their aberrant self-renewal and differentiation. The increasing use of induced pluripotent stem cell (iPSC) technology to study myeloid malignancies has helped usher a paradigm shift in approaches to disease modeling and drug discovery, especially when combined with gene-editing technology. The process of reprogramming allows for the capture of the diversity of genetic lesions and mutational burden found in primary patient samples into individual stable iPSC lines. Patient-derived iPSC lines, owing to their self-renewal and differentiation capacity, can thus be a homogenous source of disease relevant material that allow for the study of disease pathogenesis using various functional read-outs. Furthermore, genome editing technologies like CRISPR/Cas9 enable the study of the stepwise progression from normal to malignant hematopoiesis through the introduction of specific driver mutations, individually or in combination, to create isogenic lines for comparison. In this review, we survey the current use of iPSCs to model acquired myeloid malignancies including myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPN), acute myeloid leukemia and MDS/MPN overlap syndromes. The use of iPSCs has enabled the interrogation of the underlying mechanism of initiation and progression driving these diseases. It has also made drug testing, repurposing, and the discovery of novel therapies for these diseases possible in a high throughput setting.

STIMULUS-MDS2 design and rationale: a phase III trial with the anti-TIM-3 sabatolimab (MBG453) + azacitidine in higher risk MDS and CMML-2

Patients with higher-risk myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML) unfit for hematopoietic stem cell transplantation have poor outcomes. Novel therapies that provide durable benefit with favorable tolerability and clinically meaningful improvement in survival are needed. T-cell immunoglobulin domain and mucin domain-3 (TIM-3) is an immuno-myeloid regulator expressed on immune and leukemic stem cells in myeloid malignancies. Sabatolimab is a novel immunotherapy targeting TIM-3 with a potential dual mechanism of reactivating the immune system and directly targeting TIM-3+ leukemic blasts suppressing the growth of cancer cells. Here, we describe the aims and design of the phase III STIMULUS-MDS2 trial, which aims to demonstrate the potential for sabatolimab plus azacitidine to improve survival for patients with higher-risk MDS and CMML-2 (NCT04266301). Clinical Trial Registration: NCT04266301 (ClinicalTrials.gov).

Splicing factor mutations in the myelodysplastic syndromes: Role of key aberrantly spliced genes in disease pathophysiology and treatment

Mutations of splicing factor genes (including SF3B1, SRSF2, U2AF1 and ZRSR2) occur in more than half of all patients with myelodysplastic syndromes (MDS), a heterogeneous group of myeloid neoplasms. Splicing factor mutations lead to aberrant pre-mRNA splicing of many genes, some of which have been shown in functional studies to impact on hematopoiesis and to contribute to the MDS phenotype. This clearly demonstrates that impaired spliceosome function plays an important role in MDS pathophysiology. Recent studies that harnessed the power of induced pluripotent stem cell (iPSC) and CRISPR/Cas9 gene editing technologies to generate new iPSC-based models of splicing factor mutant MDS, have further illuminated the role of key downstream target genes. The aberrantly spliced genes and the dysregulated pathways associated with splicing factor mutations in MDS represent potential new therapeutic targets. Emerging data has shown that IRAK4 is aberrantly spliced in SF3B1 and U2AF1 mutant MDS, leading to hyperactivation of NF-κB signaling. Pharmacological inhibition of IRAK4 has shown efficacy in pre-clinical studies and in MDS clinical trials, with higher response rates in patients with splicing factor mutations. Our increasing knowledge of the effects of splicing factor mutations in MDS is leading to the development of new treatments that may benefit patients harboring these mutations.

Precision analysis of mutant U2AF1 activity reveals deployment of stress granules in myeloid malignancies

Splicing factor mutations are common among cancers, recently emerging as drivers of myeloid malignancies. U2AF1 carries hotspot mutations in its RNA-binding motifs; however, how they affect splicing and promote cancer remain unclear. The U2AF1/U2AF2 heterodimer is critical for 3' splice site (3'SS) definition. To specifically unmask changes in U2AF1 function in vivo, we developed a crosslinking and immunoprecipitation procedure that detects contacts between U2AF1 and the 3'SS AG at single-nucleotide resolution. Our data reveal that the U2AF1 S34F and Q157R mutants establish new 3'SS contacts at -3 and +1 nucleotides, respectively. These effects compromise U2AF2-RNA interactions, resulting predominantly in intron retention and exon exclusion. Integrating RNA binding, splicing, and turnover data, we predicted that U2AF1 mutations directly affect stress granule components, which was corroborated by single-cell RNA-seq. Remarkably, U2AF1-mutant cell lines and patient-derived MDS/AML blasts displayed a heightened stress granule response, pointing to a novel role for biomolecular condensates in adaptive oncogenic strategies.

LncRNA BC200/miR-150-5p/MYB positive feedback loop promotes the malignant proliferation of myelodysplastic syndrome

Myelodysplastic syndrome (MDS) is a group of heterogeneous hematologic malignancies with a risk of transformation to acute myeloid leukemia. Understanding the molecular mechanisms of the specific roles of long noncoding RNAs (lncRNAs) in MDS would create novel ways to identify diagnostic and therapeutic targets. The lncRNA BC200 is upregulated and acts as an oncogene in various cancers; however, its expression, clinical significance, and roles in MDS remain unclear. Here, we found that BC200 was highly expressed in MDS patients compared with normal individuals. Knockdown of BC200 inhibited MDS cell proliferation, colony formation, and cell cycle progression in vitro and suppressed the growth and invasiveness of MDS cells in vivo. Mechanistic investigations revealed that BC200 functioned as a miRNA sponge to positively regulate the expression of MYB through sponging miR-150-5p and subsequently promoted malignant proliferation of MDS cells. Conversely, we found that BC200 was a direct transcriptional target of MYB, and knockdown of MYB abolished the oncogenic effect of BC200/miR-150-5p. Taken together, our results revealed that the BC200/miR-150-5p/MYB positive feedback loop promoted the proliferation of MDS cells and is expected to be a potential biomarker and therapeutic target in MDS.

The expression and clinical significance of CD59 and FLAER in Chinese adult AML patients

Background

The role of CD59 and fluorescently labeled aerolysin (FLAER) in acute myeloid leukemia (AML) remains unclear and requires further investigation. To explore the relationship between CD59, FLAER, and AML, we investigated CD59 and FLAER expression in AML and analyzed their relationship with clinical characteristics of AML patients.

Methods

We employed flow cytometry (FCM) to analyze CD59 and FLAER expression in 161 AML patients at Tianjin Medical University General Hospital and evaluated its association with sex, white blood cell (WBC) count, platelet (PLT) count, thrombin time (TT), prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), D‐Dimer(D‐D), and lactate dehydrogenase (LDH), followed by analyzing its connection with disease progression and complete remission (CR).

Results

CD59 and FLAER deficiencies were identified in AML patients. Compared with CR group, non‐CR group patients revealed more CD59 and FLAER deficiency. Compared with non‐acute promyelocytic leukemia (M3) group, M3 group patients had more CD59 and FLAER deficiency. CD59⁻ level in primordial cells of M3 patients was positively correlated with primordial cell ratio (r = 0.660, p = 0.003). Additionally, we discovered that the decline in CD59 and FLAER levels might be linked to higher D‐D and LDH in AML patients. The difference was statistically significant (p < 0.05).

Conclusions

We demonstrated that the decline in CD59 and FLAER levels was associated with leukemia cell proliferation and abnormal coagulation function in AML, suggesting that they could serve as a predictor of AML coagulation dysfunction, particularly in M3.

A novel all-trans retinoic acid derivative regulates cell cycle and differentiation of myelodysplastic syndrome cells by USO1

4-Amino-2-Trifluoromethyl-Phenyl Retinate (ATPR), a novel all-trans retinoic acid (ATRA) derivative, has been demonstrated that it had a variety of anti-tumor effects by exerting regulation on cellular proliferation, apoptosis and differentiation. Here, we found that ATPR is critical for alleviating myelodysplastic syndrome (MDS) and acute myelogenous leukemia. USO1, vesicle transport factor, belongs to tether protein family and involved in endoplasmic reticulum to Golgi trafficking of protein which is important to tumorigenesis. How USO1 contribute to MDS remain elusive. USO1 is aberrantly activated in MDS and AML in vivo and vitro, aberration of which might be a dominant mechanism for MDS cell survival. During the ATPR-induced remission of MDS, in vitro, USO1 presents a time and concentration-dependent decrease. Silencing of USO1 promotes myeloid differentiation of MDS cells and inhibits MDS cellular proliferation while USO1 over-expression has the opposite effect, suggesting that reduction of USO1 enhances the sensitivity of SKM-1 cells to ATPR treatment. Mechanistically, USO1 exerts its oncogenic role by inactivating Raf/ERK signaling, while ATPR is access to revise it. Notably, the activity of Raf/ERK pathway is required for the development and maintenance of MDS cell proliferation. Collectively, our results demonstrate the USO1- Raf/ERK signaling axis in MDS and highlight the negative role of USO1 in ATPR-regulated remission of MDS.

A Review of Romiplostim Mechanism of Action and Clinical Applicability

Thrombocytopenia results from a variety of conditions, including radiation, chemotherapy, autoimmune disease, bone marrow disorders, pathologic conditions associated with surgical procedures, hematopoietic stem cell transplant (HSCT), and hematologic disorders associated with severe aplastic anemia. Immune thrombocytopenia (ITP) is caused by immune reactions that accelerate destruction and reduce production of platelets. Thrombopoietin (TPO) is a critical component of platelet production pathways, and TPO receptor agonists (TPO-RAs) are important for the management of ITP by increasing platelet production and reducing the need for other treatments. Romiplostim is a TPO-RA approved for use in patients with ITP in the United States, European Union, Australia, and several countries in Africa and Asia, as well as for use in patients with refractory aplastic anemia in Japan and Korea. Romiplostim binds to and activates the TPO receptor on megakaryocyte precursors, thus promoting cell proliferation and viability, resulting in increased platelet production. Through this mechanism, romiplostim reduces the need for other treatments and decreases bleeding events in patients with thrombocytopenia. In addition to its efficacy in ITP, studies have shown that romiplostim is effective in improving platelet counts in various settings, thereby highlighting the versatility of romiplostim. The efficacy of romiplostim in such disorders is currently under investigation. Here, we review the structure, mechanism, pharmacokinetics, and pharmacodynamics of romiplostim. We also summarize the clinical evidence supporting its use in ITP and other disorders that involve thrombocytopenia, including chemotherapy-induced thrombocytopenia, aplastic anemia, acute radiation syndrome, perisurgical thrombocytopenia, post-HSCT thrombocytopenia, and liver disease.

Lower-dose decitabine improves clinical response compared with best supportive care in lower-risk MDS patients: a prospective, multicenter phase 2 study

Purpose: To explore the efficacy and safety of lower-dose decitabine in patients with lower-risk MDS, a prospective multicenter phase II study was conducted to compare decitabine with the best supportive care (BSC).

Methods: Patients diagnosed with lower-risk MDS from September 2013 to August 2018 were assigned to the decitabine group or the BSC group. Decitabine (12 mg/m²/day) was administered over 1 hour/day for 5 consecutive days in a 4-week cycle. BSC, including growth factors, transfusion, thalidomide, lenalidomide, and immunosuppressive agents were given consecutively. The endpoints included the proportion of patients who achieved overall response (OR) in the first 2 or 3 courses, event-free survival (EFS), and overall survival (OS).

Results: A total of recruited 82 patients were analyzed. In the decitabine group, 65.9% (27/41) achieved OR after 2 or 3 cycles of treatment, compared with 22.0% (9/41) in the BSC group (p <0.01). Besides, 44.0% (11/25) in the decitabine group became independent of RBC/Platelets transfusion, compared with 27.8% (5/18) in the BSC group. Patients with gene mutation and treated with decitabine achieved a higher OR rate, compared with those without gene mutation [72.0% (18/25) vs 11.5% (3/26), p <0.01]. There was no significant difference in the median EFS between the decitabine and BSC groups (20.6 vs 14.3 months respectively, p = 0.665). In the decitabine group, the most significant adverse events were infections of any grades or neutropenic fever (46.3%, 19/41) and one patient (4.2%) died of acute cerebral infarction within 6 weeks of treatment.

Conclusion: Lower-dose decitabine demonstrated promising clinical response with acceptable toxicity profiles in patients with low- and intermediate 1-risk MDS. A higher response rate to decitabine was observed in patients with mutated genes. Therefore, lower-dose decitabine can be advocated for patients with low-risk MDS and mutated genes.

TIFAB Regulates USP15-Mediated p53 Signaling during Stressed and Malignant Hematopoiesis

TRAF-interacting protein with a forkhead-associated domain B (TIFAB) is implicated in myeloid malignancies with deletion of chromosome 5q. Employing a combination of proteomic and genetic approaches, we find that TIFAB regulates ubiquitin-specific peptidase 15 (USP15) ubiquitin hydrolase activity. Expression of TIFAB in hematopoietic stem/progenitor cells (HSPCs) permits USP15 signaling to substrates, including MDM2 and KEAP1, and mitigates p53 expression. Consequently, TIFAB-deficient HSPCs exhibit compromised USP15 signaling and are sensitized to hematopoietic stress by derepression of p53. In MLL-AF9 leukemia, deletion of TIFAB increases p53 signaling and correspondingly decreases leukemic cell function and development of leukemia. Restoring USP15 expression partially rescues the function of TIFAB-deficient MLL-AF9 cells. Conversely, elevated TIFAB represses p53, increases leukemic progenitor function, and correlates with MLL gene expression programs in leukemia patients. Our studies uncover a function of TIFAB as an effector of USP15 activity and rheostat of p53 signaling in stressed and malignant HSPCs.

Niederkorn et al. identify TIFAB as a critical node in hematopoietic cells under stressed and oncogenic cell states. Their studies indicate that deregulation of the TIFAB-USP15 complex, as observed in del(5q) myelodysplasia or MLL-rearranged leukemia, modulates p53 activity and has critical functional consequences for stressed and malignant hematopoietic cells.

Phyllanthin inhibits MOLT-4 leukemic cancer cell growth and induces apoptosis through the inhibition of AKT and JNK signaling pathway

Among cancers, leukemia is a multistep progression that involves genetic modifications of normal hematopoietic progenitor cells to cancerous cells. In recent times, leukemia cases and their mortality rate have increased rapidly. Therefore, the immense need for a therapeutic approach is crucial that can control this type of cancer. Phyllanthin is a lignan compound constituent from the Phyllanthus species and has numerous beneficial effects as a dietary component. The present study aims to determine the impact of phyllanthin on the MOLT-4 cytotoxic effect. MOLT-4 cells and MS-5 cells were cultured at different concentrations of phyllanthin (5, 10, 25, 50, 75, and 100 μM/ml), and the viability was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. The level of reactive oxygen species, the membrane potential of mitochondria, apoptosis by 2',7'-dichlorofluorescin-diacetate (DCF-DA), rhodamine, acridine orange (AO)/ethidium bromide (EB), 4',6-diamidino-2-phenylindole (DAPI)/propidium iodide (PI) staining, gene expression of signaling molecules, and protein levels were assessed by reverse-transcription polymerase chain reaction and western blot analysis. Phyllanthin did not show toxicity toward MS-5 cells and significantly decreased the cell viability of MOLT-4 cells with an IC₅₀ value of 25 µM/ml. Also, phyllanthin induced the production of reactive oxygen species and led to the loss of mitochondrial membrane potential. AO/EB and DAPI/PI staining fluorescent image confirmed the induction of apoptosis by phyllanthin treatment. The messenger RNA (mRNA) expression of cell cycle regulator cyclin D1, antiapoptotic gene Bcl-2, NF-κB, and TNF-α decreased, but the proapoptotic Bax mRNA expression was increased. The phosphorylated protein levels of p-PI3K1/2, p-ERK1/2, and p-AKT were decreased, whereas the levels of p-p38 and p-JNKT1/2 increased. Our results confirmed that phyllanthin inhibits the MOLT-4 cells, increases apoptosis, and inhibits MOLT-4 migration and cell invasion. Therefore, phyllanthin can be used as a potential target for leukemia treatment.

Potential Therapeutic Targets of Quercetin, a Plant Flavonol, and Its Role in the Therapy of Various Types of Cancer through the Modulation of Various Cell Signaling Pathways

Polyphenolic flavonoids are considered natural, non-toxic chemopreventers, which are most commonly derived from plants, fruits, and vegetables. Most of these polyphenolics exhibit remarkable antioxidant, anti-inflammatory, and anticancer properties. Quercetin (Qu) is a chief representative of these polyphenolic compounds, which exhibits excellent antioxidant and anticancer potential, and has attracted the attention of researchers working in the area of cancer biology. Qu can regulate numerous tumor-related activities, such as oxidative stress, angiogenesis, cell cycle, tumor necrosis factor, proliferation, apoptosis, and metastasis. The anticancer properties of Qu mainly occur through the modulation of vascular endothelial growth factor (VEGF), apoptosis, phosphatidyl inositol-3-kinase (P13K)/Akt (proteinase-kinase B)/mTOR (mammalian target of rapamycin), MAPK (mitogen activated protein kinase)/ERK1/2 (extracellular signal-regulated kinase 1/2), and Wnt/β-catenin signaling pathways. The anticancer potential of Qu is documented in numerous in vivo and in vitro studies, involving several animal models and cell lines. Remarkably, this phytochemical possesses toxic activities against cancerous cells only, with limited toxic effects on normal cells. In this review, we present extensive research investigations aimed to discuss the therapeutic potential of Qu in the management of different types of cancers. The anticancer potential of Qu is specifically discussed by focusing its ability to target specific molecular signaling, such as p53, epidermal growth factor receptor (EGFR), VEGF, signal transducer and activator of transcription (STAT), PI3K/Akt, and nuclear factor kappa B (NF-κB) pathways. The anticancer potential of Qu has gained remarkable interest, but the exact mechanism of its action remains unclear. However, this natural compound has great pharmacological potential; it is now believed to be a complementary—or alternative—medicine for the prevention and treatment of different cancers.

Changes in Apoptotic Pathways in MOLM-13 Cell Lines after Induction of Resistance to Hypomethylating Agents

We established the following two variants of the MOLM-13 human acute myeloid leukemia (AML) cell line: (i) MOLM-13/DAC cells are resistant to 5-aza-2′-deoxycytidine (DAC), and (ii) MOLM-13/AZA are resistant to 5-azacytidine (AZA). Both cell variants were obtained through a six-month selection/adaptation procedure with a stepwise increase in the concentration of either DAC or AZA. MOLM-13/DAC cells are resistant to DAC, and MOLM-13/AZA cells are resistant to AZA (approximately 50-fold and 20-fold, respectively), but cross-resistance of MOLM-13/DAC to AZA and of MOLM-13/AZA to DAC was not detected. By measuring the cell retention of fluorescein-linked annexin V and propidium iodide, we showed an apoptotic mode of death for MOLM-13 cells after treatment with either DAC or AZA, for MOLM-13/DAC cells after treatment with AZA, and for MOLM-13/AZA cells after treatment with DAC. When cells progressed to apoptosis, via JC-1 (5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethyl-imidacarbocyanine iodide) assay, we detected a reduction in the mitochondrial membrane potential. Furthermore, we characterized promoter methylation levels for some genes encoding proteins regulating apoptosis and the relation of this methylation to the expression of the respective genes. In addition, we focused on determining the expression levels and activity of intrinsic and extrinsic apoptosis pathway proteins.

SF3B1 mutant myelodysplastic syndrome: Recent advances

The myelodysplastic syndromes (MDS) are common myeloid malignancies. Mutations in genes encoding different components of the spliceosome occur in more than half of all MDS patients. SF3B1 is the most frequently mutated splicing factor gene in MDS, and there is a strong association between SF3B1 mutations and the presence of ring sideroblasts in the bone marrow of MDS patients. It has been recently proposed that SF3B1 mutant MDS should be recognized as a distinct nosologic entity. Splicing factor mutations cause aberrant pre-mRNA splicing of many target genes, some of which have been shown to impact on hematopoiesis in functional studies. Emerging data show that some of the downstream effects of different mutated splicing factors converge on common cellular processes, such as hyperactivation of NF-κB signaling and increased R-loops. The aberrantly spliced target genes and the dysregulated pathways and cellular processes associated with splicing factor mutations provided the rationale for new potential therapeutic approaches to target MDS cells with mutations of SF3B1 and other splicing factors.

Fit older adults with advanced myelodysplastic syndromes: who is most likely to benefit from transplant?

We conducted a prospective observational study of fit adults aged 60 to 75 with advanced MDS, enrolled hierarchically for adverse MDS risk (intermediate-2 or high-risk international prognostic score [IPSS], low or intermediate-1 IPSS with poor-risk cytogenetics, or therapy-related MDS) or standard risk with severe cytopenia. A total of 290 patients enrolled at two centers: 175 for adverse risk and 115 for standard risk with severe cytopenia. 113 underwent HCT after a median of 5 months; median follow-up for all was 39.5 months. In univariable analyses, the hazard ratio (HR) for death comparing HCT with no HCT was 0.84 (p=0.30). The HR for death was 0.64 (p=0.04) for HCT ≤5 months after enrollment and 1.20 (p=0.39) for HCT >5 months. In multivariable analyses controlling for age, gender, ECOG performance status, cytogenetic risk, and IPSS risk group, HR for death was 0.75 (p=0.13) for HCT compared to no HCT, 0.57 (p=0.01) for adverse MDS risk and 1.33 (p=0.36) for standard risk with severe cytopenia. In this large, prospective cohort of fit older adults with advanced MDS, we found that survival was significantly improved if HCT was performed early or for adverse risk disease but not for standard risk disease with severe cytopenia.

Hypomethylating agent based combinations in higher risk myelodysplastic syndrome

For over a decade the hypomethylating agents (HMA) azacitidine and decitabine have been the mainstay of therapy for myelodysplastic syndrome (MDS). There is a critical need to improve frontline therapy, given that only up to half of high-risk MDS patients will respond to HMA therapy, and responses are short-lived. Currently, a key strategy has been to combine HMAs with other novel agents to improve patient outcomes. While synergy of agents is the goal of combination therapy, combinations often come at the cost of increased side effects that are often intolerable in this vulnerable population. The purpose of this review is to critically examine clinically relevant HMA combinations and discuss the future of MDS management.

Comparison of Hypomethylator Monotherapy with Hypomethylator plus Chemotherapy for Intermediate/High-Risk MDS or AML: A Meta-Analysis

Aim: This meta-analysis aimed to compare the efficacy, survival benefit and safety of hypomethylating agents (HMA) monotherapy and combination with chemotherapy in patients with intermediate/high-risk MDS or AML.

Methods: Related articles published between January 2009 and April 2019 were selected and patients were separated as monotherapy group and combination group for meta-analysis. Studies on HMA combination therapy were further divided into two subgroups according to the intensity of combined chemotherapy. Meanwhile, subgroups with similar patients' baseline characteristics were selected for further analysis. Complete response (CR) rate, overall response (ORR) rate, two-year overall survival (OS) rate, one-month and 24-month death rate and the proportion of adverse events (AE) were pooled and compared.

Results: 21 RCT or cohort studies with 1764 patients (1266 patients for monotherapy group and 498 patients for HMA combination group) were selected for meta-analysis. For the pooled data, the age of patients was significantly younger and the percentage of patients with favorable/intermediate cytogenetic risk was significantly higher in the HMA combination group than that in the HMA monotherapy group. Combination therapy group had a significantly higher CR and ORR rate (55% vs 22%, P=0.000 for CR and 67% vs 42%, P=0.000 for ORR), and a higher two-year OS rate (37% vs 21%, P=0.000). However, the incidence of infection and gastrointestinal disorder was significantly higher (51% vs 23% for infection, P=0.000; 21% vs 0% for gastrointestinal disorder, P=0.000) in combination group. In subgroups with different intensity of combined chemotherapy, all baseline characteristics were compatible except that the percentage of patients with favorable/intermediate cytogenetic risk was significantly lower (63% vs 88%, P=0.000) in the HMA + high-intensity chemotherapy subgroup, and this group presented with a lower CR and ORR rate (46% vs 65% for CR, P=0.000; 57% vs 79% for ORR, P=0.000), but a compatible two-month to 24-month death rate compared with HMA + low-intensity chemotherapy subgroup (9% vs 14% for 2-month death rate, P=0.060; 58% vs 65% for 24-month death rate, P=0.242). In subgroup with similar patients' baseline characteristics, 208 and 205 patients were included in combination group and HMA monotherapy group, respectively. Although combination group had a significantly higher CR rate (62% vs 24%, P=0.000) and ORR rate (68% vs 48%, P=0.000), it finally had a lower two-year OS (30% vs 45%, P=0.001) compared with monotherapy group, and the death rate was significantly higher since the ninth month in combination therapy group than that in the monotherapy group (42% vs 31%, P=0.032). In this subgroup, patients with HMA+ high-intensity chemotherapy had a compatible CR, ORR and 1.5-year OS rate as compared with baseline-compatible patients with HMA + low-intensity chemotherapy.

Conclusions: HMA combined with chemotherapy could increase CR rate and ORR rate in all patients. HMA combined with high-intensity chemotherapy can rescue the 2-year OS with less favorable cytogenetic stratification to some extent. For patients with similar older age and risk stratification, combination therapy even had a lower long-term OS regardless of the intensity of combined chemotherapy.

Targeting Aberrant Splicing in Myelodysplastic Syndromes: Biologic Rationale and Clinical Opportunity

Myelodysplastic syndromes are enriched for somatic mutations in the pre-mRNA splicing apparatus, with recurrent acquired mutations most commonly occurring in SF3B1, SRSF2, U2AF1, and ZRSR2. These mutations appear to be early events in the pathogenesis of disease, and, given their frequency and central role in leukemogenesis, are of interest as potential therapeutic targets. Clinical trials are exploring targets that directly affect the spliceosome (splicing modulators or protein arginine methyltransferase 5 inhibitors) or that exploit possible vulnerabilities created by alternative splicing (inhibiting ATR). Future research is needed to explore novel targets and therapeutic combinations and understand how these mutations lead to clonal dominance.

Distinct and convergent consequences of splice factor mutations in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are characterized by recurrent somatic alterations often affecting components of RNA splicing machinery. Mutations of splice factors SF3B1, SRSF2, ZRSR2 and U2AF1 occur in >50% of MDS. To assess the impact of spliceosome mutations on splicing and to identify common pathways/genes affected by distinct mutations, we performed RNA-sequencing of MDS bone marrow samples harboring spliceosome mutations (including hotspot alterations of SF3B1, SRSF2 and U2AF1; small deletions of SRSF2 and truncating mutations of ZRSR2), and devoid of other common co-occurring mutations. We uncover the landscape of splicing alterations in each splice factor mutant MDS and demonstrate that small deletions in SRSF2 cause highest number of splicing alterations compared with other spliceosome mutations. Although the mis-spliced events observed in different splice factor mutations were largely non-overlapping, a subset of genes, including EZH2, were aberrantly spliced in multiple mutant groups. We also verified aberrant splicing of key genes USP9X, USP24 (deubiquitinating enzymes), LUC7L2 (splice factor) and EED (PRC2 component) in MDS harboring small deletions of SRSF2. Pathway analysis revealed that mis-spliced genes in different mutant groups were enriched in RNA splicing and transport as well as several signaling cascades, suggesting converging biological consequences downstream of distinct spliceosome mutations. Our study reveals splicing signatures of each splice factor mutation and identifies shared and distinct sets of mis-spliced genes and affected biological processes in different spliceosome mutant MDS.

Impact of marrow blasts percentage on high-grade myelodysplastic syndrome assessed using revised international prognostic scoring system

Clinical trials and treatment guidelines for myelodysplastic syndrome depend on several prognostic scoring systems to stratify patients by risk. These include different variables: the degree of cytopenia, percentage of bone marrow blasts, and cytogenetics. Little is known about the impact of bone marrow blasts in patients with adverse cytogenetics. In this retrospective study, we analyzed 536 patients with high-grade myelodysplastic syndrome to examine the differences in survival for patients with different percentages of bone marrow blasts. The median overall survival in patients with ≥ 5% marrow blasts was not statistically different from that for patients with < 5% marrow blasts; however, the former group had a higher risk of progression to acute myeloid leukemia (p < 0.001). Therefore, cytogenetics is the most important factor in our prognostic tools to determine survival outcomes for patients with myelodysplastic syndrome, and patients with high-risk disease have poor prognosis irrespective of their marrow blasts percentage.

Treatment of Anemia in Transfusion-Dependent and Non-Transfusion-Dependent Lower-Risk MDS: Current and Emerging Strategies

Myelodysplastic syndromes (MDS) are a heterogeneous group of bone marrow disorders with a highly diverse clinical course. For lower-risk MDS patients, therapeutic objectives aim to correct chronic anemia and improve/maintain health-related quality of life (HRQoL). However, disease burden is often insufficiently recognized, and although some patients do not respond/lose response to standard treatment, many are treated late. This is the case for non-transfusion-dependent patients with symptomatic anemia, in whom delayed treatment initiation may lead to unnecessary morbidity. Current active treatment options for lower-risk MDS are limited. Standard care for lower-risk 5q deletion [del(5q)] MDS patients with anemia remains supportive, consisting of red blood cell (RBC) transfusions, iron chelation therapy, and treatment with erythropoiesis-stimulating agents (ESAs) in the case of low serum erythropoietin levels. Response rates to ESAs range from 15% to 63%, whereas 56% to 67% of patients with del(5q) MDS achieve RBC transfusion independence with lenalidomide. Treatment options for patients’ refractory to ESAs and/or lenalidomide, however, are limited. Frequent transfusions are associated with profound clinical, HRQoL, and economic consequences for transfusion-dependent patients. This review focuses on the multiple unmet clinical needs that exist in the treatment of anemia associated with lower-risk MDS and the current and future treatment options that may improve disease management and patient outcomes.

Splicing factor mutant myelodysplastic syndromes: Recent advances

The myelodysplastic syndromes (MDS) are common myeloid malignancies showing frequent progression to acute myeloid leukemia (AML). Pre-mRNA splicing is an essential cellular process carried out by the spliceosome. Mutations in splicing factor genes (including SF3B1, SRSF2, U2AF1 and ZRSR2) occur in over half of MDS patients and result in aberrant pre-mRNA splicing of many target genes, implicating aberrant spliceosome function in MDS disease pathogenesis. Recent functional studies have illuminated the impact on hematopoiesis of some aberrantly spliced target genes associated with splicing factor mutations. Emerging data show that the commonly mutated splicing factors have convergent effects on aberrant splicing of mRNAs that promote NF-κB signaling and on R-loop elevation leading to DNA damage, providing novel insights into MDS disease pathophysiology. It is recognized that the survival of splicing factor mutant cells is dependent on the presence of the wildtype allele, providing a rationale for the use of spliceosome inhibitors in splicing factor mutant MDS. Pre-clinical studies involving E7107 and H3B-8800 have shown the potential of these spliceosome inhibitors for the treatment of splicing factor mutant MDS and AML.

A man with polycythemia vera, myelodysplastic syndrome and acquired microcytosis

A 59-year-old white man with known myeloproliferative neoplasm (MPN) and myelodysplastic syndrome (MDS) presented with worsening leucocytosis and thrombocytosis in the setting of a presumed infection. The patient had been diagnosed 2 years earlier with an MPN/MDS overlap syndrome, based on characteristic mutations in JAK2, IDH1 and SRSF2. During his current evaluation, he was noted to have new microcytosis, with a mean corpuscular volume of ~70 fL down from his baseline of ~90 fL. His laboratory workup showed normal iron studies, normal haemoglobin electrophoresis, and no evidence of haemoglobin H or mutations in his ATRX coding region. Without any identifiable cause of his new microcytosis, he was given a presumptive diagnosis of acquired thalassemia in the setting of his unusual MPN/MDS overlap syndrome.

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.

Decitabine improves overall survival in myelodysplastic syndromes-RAEB patients aged ≥60 years and has lower toxicities: Comparison with low-dose chemotherapy

Decitabine and low-dose chemotherapy are common treatments for intermediate and high risk myelodysplastic syndromes (MDS). In this study, we retrospectively assessed the efficacy and toxicity of the two regimens for MDS-refractory anemia with excess blasts (MDS-RAEB) patients. A total of 112 patients with a diagnosis of MDS-RAEB are included. The overall response (OR) and complete remission (CR) rate was comparable between the two groups (OR: 64.1% vs. 66.7%, p = 0.60; CR: 23.4% vs. 31.3%, p = 0.64). The OR rates of 20 mg/m²/day and 15 mg/m²/day decitabine regimen were comparable (69.0% vs. 60.0%, p = 0.46). Overall survival (OS) did not differ significantly between the groups (20.7 vs. 13.5 months, p = 0.17). In a subgroup analysis that included only patients at ≥60 years of age, survival benefit of decitabine was apparent (20.6 vs. 10.0 months, p = 0.03). In hematological toxicities, the lowest count of platelet in the decitabine group was higher significantly. And, the incidence of Grade 3-4 infection in the decitabine group was lower significantly. Our results demonstrate that both decitabine and low-dose chemotherapy are effective for MDS-RAEB, but decitabine was safer. Decitabine might be a better choice for patients at ≥60 years of age.

Efficacy of granulocyte colony stimulating factor in combination with erythropoiesis stimulating agents for treatment of anemia in patients with lower risk myelodysplastic syndromes: A systematic review

Anemic patients with lower risk myelodysplastic syndromes are frequently treated with erythropoiesis stimulating agents (ESA), eventually in combination with granulocyte colony stimulating factor (G-CSF). However, the evidence for the efficacy of a combined treatment remains controversial. The goal of our analysis was to assess the available evidence for a combined treatment. We performed a systematic review and identified only nine eligible studies. In two randomized controlled trials (n = 98), erythroid response rates were 33% and 40% after low-/standard-doses of ESA alone (10,000-30,000 rHuEPO equivalents/week) versus 65% and 73% after combination treatment. In seven trials with sequential drug administration (n = 393), erythroid response rates ranged from 12% to 71% after full-doses of ESA alone (60,000-80,000 rHuEPO equivalents/week) and from 35% to 74% after combination therapy. Our analysis supports an additional efficacy of G-CSF added to low-/standard-dose ESA, but the available data remains controversial, if G-CSF is added to full-dose ESA.

The polyphenol quercetin induces cell death in leukemia by targeting epigenetic regulators of pro-apoptotic genes

Background

In the present study, we investigated the molecular mechanisms underlying the pro-apoptotic effects of quercetin (Qu) by evaluating the effect of Qu treatment on DNA methylation and posttranslational histone modifications of genes related to the apoptosis pathway. This study was performed in vivo in two human xenograft acute myeloid leukemia (AML) models and in vitro using HL60 and U937 cell lines.

Results

Qu treatment almost eliminates DNMT1 and DNMT3a expression, and this regulation was in part STAT-3 dependent. The treatment also downregulated class I HDACs. Furthermore, treatment of the cell lines with the proteasome inhibitor, MG132, together with Qu prevented degradation of class I HDACs compared to cells treated with Qu alone, indicating increased proteasome degradation of class I HDACS by Qu. Qu induced demethylation of the pro-apoptotic BCL2L11, DAPK1 genes, in a dose- and time-dependent manner. Moreover, Qu (50 μmol/L) treatment of cell lines for 48 h caused accumulation of acetylated histone 3 and histone 4, resulting in three- to ten fold increases in the promoter region of DAPK1, BCL2L11, BAX, APAF1, BNIP3, and BNIP3L. In addition, Qu treatment significantly increased the mRNA levels of all these genes, when compared to cells treated with vehicle only (control cells) (*p < 0.05).

Conclusions

In summary, our results showed that enhanced apoptosis, induced by Qu, might be caused in part by its DNA demethylating activity, by HDAC inhibition, and by the enrichment of H3ac and H4ac in the promoter regions of genes involved in the apoptosis pathway, leading to their transcription activation.

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.

Myelodysplastic syndrome from theoretical review to clinical application view

Myelodysplastic syndromes (MDS), called ineffective hematopoiesis is indicated by bone marrow failure and tendency to acute myeloid leukemia transformation. Since the disease is more common in elderly with non- hematology co-morbidities, the research for less toxic and curative novel agents is essential. More than 12 years without new Food and Drug Administration approved drugs in MDS management through the whole course, only 5 drugs. We summarized the basic data in diagnosis, treatment guidelines and future direction.

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.

Antiplatelet Therapy in a Patient with Coronary Artery Disease and Myelodysplastic Syndrome with Thrombocytopenia

To date, there are no sufficient data to make firm recommendations on the treatment of patients with severe thrombocytopenia who require antiplatelet therapy after experiencing acute coronary syndrome. Therefore, we think that it is important to communicate the experience with individual cases. We report the case of a patient who presented with pericardial effusion causing cardiac tamponade. He had thrombocytopenia associated with myelodysplastic syndrome, and ten weeks before this admission, percutaneous transluminal coronary angioplasty with implantation of drug-eluting stents was performed for non-ST-segment elevation acute coronary syndrome. Platelets in myelodysplastic syndromes are dysfunctional, which exacerbates bleeding from thrombocytopenia, and the management of atherosclerotic cardiovascular disease in these patients is challenging.

Myelodysplastic syndromes current treatment algorithm 2018

Myelodysplastic syndromes (MDS) include a group of clonal myeloid neoplasms characterized by cytopenias due to ineffective hematopoiesis, abnormal blood and marrow cell morphology, and a risk of clonal evolution and progression to acute myeloid leukemia (AML). Because outcomes for patients with MDS are heterogeneous, individual risk stratification using tools such as the revised International Prognostic Scoring System (IPSS-R) is important in managing patients-including selecting candidates for allogeneic hematopoietic stem cell transplantation (ASCT), the only potentially curative therapy for MDS. The IPSS-R can be supplemented by molecular genetic testing, since certain gene mutations such as TP53 influence risk independent of established clinicopathological variables. For lower risk patients with symptomatic anemia, treatment with erythropoiesis-stimulating agents (ESAs) or lenalidomide (especially for those with deletion of chromosome 5q) can ameliorate symptoms. Some lower risk patients may be candidates for immunosuppressive therapy, thrombopoiesis-stimulating agents, or a DNA hypomethylating agent (HMA; azacitidine or decitabine). Among higher risk patients, transplant candidates should undergo ASCT as soon as possible, with HMAs useful as a bridge to transplant. Non-transplant candidates should initiate HMA therapy and continue if tolerated until disease progression. Supportive care with transfusions and antimicrobial drugs as needed remains important in all groups.

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.

Is bone marrow examination always necessary to establish the diagnosis of myelodysplastic syndromes? A proposed non-invasive diagnostic model

A non-invasive myelodysplastic syndromes (MDS) diagnostic model would allow for care while avoiding invasive bone marrow examinations (BME). BME-established MDS patients were compared to non-MDS (BME-excluded) patients. Variables (gender, age, hemoglobin (Hb), mean red blood cell corpuscular volume (MCV), platelet (PLT), and white blood cell (WBC)) were combined with multivariate logistic regression; a probability score (Y) was calculated. MDS (n = 48) and non-MDS (n = 63) patients were used to establish the model. The ROC was drawn, giving an AUC of 0.748 (95% CI: 0.656-0.84). Two cutoff values were used for Y. Y ≥ 0.633: high likelihood (positive predictive value (PPV) = 85%); Y ≤ 0.288: low likelihood (negative predictive value (NPV) = 81%) of MDS. The first group is defined as probable MDS (pMDS); the second, probably not MDS (pnMDS). The model was validated with 40 additional patients (20 with and 20 without MDS). Using clinical and lab data, we could diagnose or exclude MDS in about half of the patients, avoiding BME. Future work will use larger cohorts of patients to improve and further validate the model.

RUNX1 Mutations in Inherited and Sporadic Leukemia

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

Iron chelation therapy in lower IPSS risk myelodysplastic syndromes; which subtypes benefit?

BACKGROUND

Analyses suggest MDS patients with higher serum ferritin levels (SF) have inferior overall survival (OS), in one study across MDS subtypes. Multiple analyses suggest those with high SF receiving iron chelation therapy (ICT) have superior OS, but which MDS subtypes benefit from ICT remains undefined.

METHODS

We performed survival analyses of MDS subtypes by receipt of ICT.

RESULTS

182 MDS were lower IPSS risk and received red blood cell (RBC) transfusions; 63 received ICT. For the entire cohort, receiving ICT independently predicted superior OS in a multivariate analysis (hazard ratio for death 0.3, p=0.01). Features differing for ICT and non-ICT patients, respectively, were: age; IPSS risk group; number of RBC units transfused; and SF, p≤0.03 for all. At a median follow up of 76.5 and 28.4 months, 65.1% and 63.0% were alive. Median OS (months) for ICT and non-ICT patients was: RA, 140.9 and 36.3, p=0.0008; RARS/RARS-t, 133.4 and 73.3, p=0.02. For RCMD/RCMD-RS, p=NS, however, 3 (20%) had significant erythroid improvement with ICT; other subtypes had small numbers.

DISCUSSION

In this retrospective analysis, RA and RARS/RARS-t patients receiving ICT had superior OS to non-ICT patients. These findings should be verified and other MDS subtypes examined in larger prospective analyses.

Targeting Splicing in the Treatment of Myelodysplastic Syndromes and Other Myeloid Neoplasms

Genome sequencing of primary cells from patients with myelodysplastic syndromes (MDS) led to the identification of recurrent heterozygous mutations in gene encoding components of the spliceosome, the cellular machinery which processes pre-messenger RNA (mRNA) to mature mRNA during gene transcription. Splicing mutations are mutually exclusive with one another and collectively represent the most common mutation class in MDS, occurring in approximately 60 % of patients overall and more than 80 % of those with ring sideroblasts. Evidence from animal models suggests that homozygous splicing mutations are lethal, and that in heterozygously mutated models, any further disruption of splicing triggers apoptosis and cell death. MDS cells with spliceosome mutations are thus uniquely vulnerable to therapies targeting splicing, which may be tolerated by healthy cells. The spliceosome is emerging as a novel therapeutic target in MDS and related myeloid neoplasms, with the first clinical trial of a splicing modulator opening in 2016.

Splicing factor mutations in the myelodysplastic syndromes: target genes and therapeutic approaches

Mutations in splicing factor genes (SF3B1, SRSF2, U2AF1 and ZRSR2) are frequently found in patients with myelodysplastic syndromes (MDS), suggesting that aberrant spliceosome function plays a key role in the pathogenesis of MDS. Splicing factor mutations have been shown to result in aberrant splicing of many downstream target genes. Recent functional studies have begun to characterize the splicing dysfunction in MDS, identifying some key aberrantly spliced genes that are implicated in disease pathophysiology. These findings have led to the development of therapeutic strategies using splicing-modulating agents and rapid progress is being made in this field. Splicing inhibitors are promising agents that exploit the preferential sensitivity of splicing factor-mutant cells to these compounds. Here, we review the known target genes associated with splicing factor mutations in MDS, and discuss the potential of splicing-modulating therapies for these disorders.

A Tox21 Approach to Altered Epigenetic Landscapes: Assessing Epigenetic Toxicity Pathways Leading to Altered Gene Expression and Oncogenic Transformation In Vitro

An emerging vision for toxicity testing in the 21st century foresees in vitro assays assuming the leading role in testing for chemical hazards, including testing for carcinogenicity. Toxicity will be determined by monitoring key steps in functionally validated molecular pathways, using tests designed to reveal chemically-induced perturbations that lead to adverse phenotypic endpoints in cultured human cells. Risk assessments would subsequently be derived from the causal in vitro endpoints and concentration vs. effect data extrapolated to human in vivo concentrations. Much direct experimental evidence now shows that disruption of epigenetic processes by chemicals is a carcinogenic mode of action that leads to altered gene functions playing causal roles in cancer initiation and progression. In assessing chemical safety, it would therefore be advantageous to consider an emerging class of carcinogens, the epigenotoxicants, with the ability to change chromatin and/or DNA marks by direct or indirect effects on the activities of enzymes (writers, erasers/editors, remodelers and readers) that convey the epigenetic information. Evidence is reviewed supporting a strategy for in vitro hazard identification of carcinogens that induce toxicity through disturbance of functional epigenetic pathways in human somatic cells, leading to inactivated tumour suppressor genes and carcinogenesis. In the context of human cell transformation models, these in vitro pathway measurements ensure high biological relevance to the apical endpoint of cancer. Four causal mechanisms participating in pathways to persistent epigenetic gene silencing were considered: covalent histone modification, nucleosome remodeling, non-coding RNA interaction and DNA methylation. Within these four interacting mechanisms, 25 epigenetic toxicity pathway components (SET1, MLL1, KDM5, G9A, SUV39H1, SETDB1, EZH2, JMJD3, CBX7, CBX8, BMI, SUZ12, HP1, MPP8, DNMT1, DNMT3A, DNMT3B, TET1, MeCP2, SETDB2, BAZ2A, UHRF1, CTCF, HOTAIR and ANRIL) were found to have experimental evidence showing that functional perturbations played “driver” roles in human cellular transformation. Measurement of epigenotoxicants presents challenges for short-term carcinogenicity testing, especially in the high-throughput modes emphasized in the Tox21 chemicals testing approach. There is need to develop and validate in vitro tests to detect both, locus-specific, and genome-wide, epigenetic alterations with causal links to oncogenic cellular phenotypes. Some recent examples of cell-based high throughput chemical screening assays are presented that have been applied or have shown potential for application to epigenetic endpoints.