Ischemic stroke as the initial presentation in acute myeloid leukemia vs. myelodysplastic syndrome: a case report and literature review with pathophysiological and clinical exploration.

BACKGROUND: Myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) present intricate challenges due to their diverse clinical manifestations and thrombotic complications. Thromboembolism (TE) incidence in newly diagnosed AML patients is noteworthy, with arterial TE linked to poorer overall survival. Ischemic strokes, although relatively low in prevalence, carry significant clinical implications. CASE DESCRIPTION: We report the case of an 84-year-old male with Type 2 Diabetes, Hypertension, and Chronic Kidney Disease, presenting with seizures, focal neurological deficits, and pancytopenia. An unexpected diagnosis of AML or MDS emerged during the investigation. Despite interventions, the patient's condition deteriorated, leading to a fatal outcome weeks later. CONCLUSION: This case underscores the intricate relationship between hematologic malignancies and ischemic stroke. The rarity of this complication emphasizes the importance of understanding the multifaceted mechanisms at play, including hyperleukocytosis, pro-inflammatory cytokine release, coagulation cascade activation, and direct interactions with endothelial cells. In our literature review, analysis of 15 cases, including ours, revealed a wide age range (3-87 years) and a gender bias towards females. AML diagnosis was predominant, with uniformly low platelet counts. Cortical infarctions, especially in the anterior circulation, were common. Hyperleukocytosis, disseminated intravascular coagulation (DIC), and fatal outcomes were observed in a subset of cases. Despite the grim statistics and often poor prognosis, the identification of specific risk factors, such as thrombocytopenia and cytogenetic abnormalities, offers avenues for targeted prevention and management.

How I treat MDS after hypomethylating agent failure.

Hypomethylating agents (HMA) azacitidine and decitabine are standard of care for myelodysplastic syndrome (MDS). Response to these agents occurs in ∼50% of treated patients, and duration of response, although variable, is transient. Prediction of response to HMAs is possible with clinical and molecular parameters, but alternative approved treatments are not available, and in the case of HMA failure, there are no standard therapeutic opportunities. It is important to develop a reasoned choice of therapy after HMA failure. This choice should be based on evaluation of type of resistance (primary vs secondary, progression of disease [acute leukemia or higher risk MDS] vs absence of hematological improvement) as well as on molecular and cytogenetic characteristics reassessed at the moment of HMA failure. Rescue strategies may include stem-cell transplantation, which remains the only curative option, and chemotherapy, both of which are feasible in only a minority of cases, and experimental agents. Patients experiencing HMA failure should be recruited to clinical experimental trials as often as possible. Several novel agents with different mechanisms of action are currently being tested in this setting. Drugs targeting molecular alterations (IDH2 mutations, spliceosome gene mutations) or altered signaling pathways (BCL2 inhibitors) seem to be the most promising.

The central role of inflammatory signaling in the pathogenesis of myelodysplastic syndromes.

In cancer biology, tumor-promoting inflammation and an inflammatory microenvironment play a vital role in disease pathogenesis. In the past decade, aberrant innate immune activation and proinflammatory signaling within the malignant clone and the bone marrow (BM) microenvironment were identified as key pathogenic drivers of myelodysplastic syndromes (MDS). In particular, S100A9-mediated NOD-like receptor protein 3 (NLRP3) inflammasome activation directs an inflammatory, lytic form of cell death termed pyroptosis that underlies many of the hallmark features of the disease. This circuit and accompanying release of other danger-associated molecular patterns expands BM myeloid-derived suppressor cells, creating a feed-forward process propagating inflammasome activation. Furthermore, somatic gene mutations of varied functional classes license the NLRP3 inflammasome to generate a common phenotype with excess reactive oxygen species generation, Wnt/ß-catenin-induced proliferation, cation flux-induced cell swelling, and caspase-1 activation. Recent investigations have shown that activation of the NLRP3 inflammasome complex has more broad-reaching importance, particularly as a possible disease-specific biomarker for MDS, and, mechanistically, as a driver of cardiovascular morbidity/mortality in individuals with age-related, clonal hematopoiesis. Recognition of the mechanistic role of aberrant innate immune activation in MDS provides a new perspective for therapeutic development that could usher in a novel class of disease-modifying agents.

Lenalidomide induces ubiquitination and degradation of CK1α in del(5q) MDS.

Lenalidomide is a highly effective treatment for myelodysplastic syndrome (MDS) with deletion of chromosome 5q (del(5q)). Here, we demonstrate that lenalidomide induces the ubiquitination of casein kinase 1A1 (CK1α) by the E3 ubiquitin ligase CUL4-RBX1-DDB1-CRBN (known as CRL4(CRBN)), resulting in CK1α degradation. CK1α is encoded by a gene within the common deleted region for del(5q) MDS and haploinsufficient expression sensitizes cells to lenalidomide therapy, providing a mechanistic basis for the therapeutic window of lenalidomide in del(5q) MDS. We found that mouse cells are resistant to lenalidomide but that changing a single amino acid in mouse Crbn to the corresponding human residue enables lenalidomide-dependent degradation of CK1α. We further demonstrate that minor side chain modifications in thalidomide and a novel analogue, CC-122, can modulate the spectrum of substrates targeted by CRL4(CRBN). These findings have implications for the clinical activity of lenalidomide and related compounds, and demonstrate the therapeutic potential of novel modulators of E3 ubiquitin ligases.

Exploiting the Role of Hypoxia-Inducible Factor 1 and Pseudohypoxia in the Myelodysplastic Syndrome Pathophysiology.

Myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal hematopoietic stem (HSCs) and/or progenitor cells disorders. The established dependence of MDS progenitors on the hypoxic bone marrow (BM) microenvironment turned scientific interests to the transcription factor hypoxia-inducible factor 1 (HIF-1). HIF-1 facilitates quiescence maintenance and regulates differentiation by manipulating HSCs metabolism, being thus an appealing research target. Therefore, we examine the aberrant HIF-1 stabilization in BMs from MDS patients and controls (CTRLs). Using a nitroimidazole-indocyanine conjugate, we show that HIF-1 aberrant expression and transcription activity is oxygen independent, establishing the phenomenon of pseudohypoxia in MDS BM. Next, we examine mitochondrial quality and quantity along with levels of autophagy in the differentiating myeloid lineage isolated from fresh BM MDS and CTRL aspirates given that both phenomena are HIF-1 dependent. We show that the mitophagy of abnormal mitochondria and autophagic death are prominently featured in the MDS myeloid lineage, their severity increasing with intra-BM blast counts. Finally, we use in vitro cultured CD34+ HSCs isolated from fresh human BM aspirates to manipulate HIF-1 expression and examine its potential as a therapeutic target. We find that despite being cultured under 21% FiO2, HIF-1 remained aberrantly stable in all MDS cultures. Inhibition of the HIF-1α subunit had a variable beneficial effect in all <5%-intra-BM blasts-MDS, while it had no effect in CTRLs or in ≥5%-intra-BM blasts-MDS that uniformly died within 3 days of culture. We conclude that HIF-1 and pseudohypoxia are prominently featured in MDS pathobiology, and their manipulation has some potential in the therapeutics of benign MDS.

Gene dosage effect of CUX1 in a murine model disrupts HSC homeostasis and controls the severity and mortality of MDS.

Monosomy 7 (-7) and del(7q) are high-risk cytogenetic abnormalities common in myeloid malignancies. We previously reported that CUX1, a homeodomain-containing transcription factor encoded on 7q22, is frequently inactivated in myeloid neoplasms, and CUX1 myeloid tumor suppressor activity is conserved from humans to Drosophila. CUX1-inactivating mutations are recurrent in clonal hematopoiesis of indeterminate potential as well as myeloid malignancies, in which they independently carry a poor prognosis. To determine the role for CUX1 in hematopoiesis, we generated 2 short hairpin RNA-based mouse models with ∼54% (Cux1mid) or ∼12% (Cux1low) residual CUX1 protein. Cux1mid mice develop myelodysplastic syndrome (MDS) with anemia and trilineage dysplasia, whereas CUX1low mice developed MDS/myeloproliferative neoplasms and anemia. In diseased mice, restoration of CUX1 expression was sufficient to reverse the disease. CUX1 knockdown bone marrow transplant recipients exhibited a transient hematopoietic expansion, followed by a reduction of hematopoietic stem cells (HSCs), and fatal bone marrow failure, in a dose-dependent manner. RNA-sequencing after CUX1 knockdown in human CD34+ cells identified a -7/del(7q) MDS gene signature and altered differentiation, proliferative, and phosphatidylinositol 3-kinase (PI3K) signaling pathways. In functional assays, CUX1 maintained HSC quiescence and repressed proliferation. These homeostatic changes occurred in parallel with decreased expression of the PI3K inhibitor, Pik3ip1, and elevated PI3K/AKT signaling upon CUX1 knockdown. Our data support a model wherein CUX1 knockdown promotes PI3K signaling, drives HSC exit from quiescence and proliferation, and results in HSC exhaustion. Our results also demonstrate that reduction of a single 7q gene, Cux1, is sufficient to cause MDS in mice.

Integrated Analysis of Long Non-Coding RNA and mRNA Expression Profile in Myelodysplastic Syndromes.

BACKGROUND: Myelodysplastic syndromes (MDS) are a heterogeneous group of myeloid malignancies. The incidence of MDS is gradually increasing, but the pathogenesis is still not very clear. Studies have shown that long non-coding RNAs (lncRNAs) play a critical role in both oncogenic and tumor-suppressive pathways. However, the function of lncRNAs in MDS is still unknown. The purpose of this study was to investigate the expression profiles and biological function of the aberrantly expressed lncRNAs and mRNAs in MDS. METHODS: We downloaded two data sets (GSE4619 and GSE19429) from the Gene Expression Omnibus database and obtained differentially expressed (DE) lncRNAs and DE-mRNAs between MDS cases and healthy controls. Then we performed systematic bioinformatics analysis to know the biological function of DE-lncRNAs and DE-mRNAs in MDS. RESULTS: We identified 40 DE-lncRNAs and 643 DE-mRNAs between MDS cases and healthy controls. Gene Ontology (GO) and pathway analysis revealed that DE-lncRNAs and DE-mRNAs were mainly involved in necroptosis, apoptosis, immunodeficiency, p53 and FoxO signaling pathways. LncRNA-mRNA co-expression and lncRNA functional similarity network showed that twelve down-regulated lncRNAs co-regulated the same target gene and they were similar in function. CONCLUSIONS: The comprehensive analysis of lncRNA and mRNA is helpful in understanding the pathogenesis of MDS, and the synergistically down-regulated lncRNAs may contribute to the development of new diagnostic and therapeutic strategies.

The role of ASXL1 in hematopoiesis and myeloid malignancies.

Recent high-throughput genome-wide sequencing studies have identified recurrent somatic mutations in myeloid neoplasms. An epigenetic regulator, Additional sex combs-like 1 (ASXL1), is one of the most frequently mutated genes in all subtypes of myeloid malignancies. ASXL1 mutations are also frequently detected in clonal hematopoiesis, which is associated with an increased risk of mortality. Therefore, it is important to understand how ASXL1 mutations contribute to clonal expansion and myeloid transformation in hematopoietic cells. Studies using ASXL1-depleted human hematopoietic cells and Asxl1 knockout mice have shown that deletion of wild-type ASXL1 protein leads to impaired hematopoiesis and accelerates myeloid malignancies via loss of interaction with polycomb repressive complex 2 proteins. On the other hand, ASXL1 mutations in myeloid neoplasms typically occur near the last exon and result in the expression of C-terminally truncated mutant ASXL1 protein. Biological studies and biochemical analyses of this variant have shed light on its dominant-negative and gain-of-function features in myeloid transformation via a variety of epigenetic changes. Based on these results, it would be possible to establish novel promising therapeutic strategies for myeloid malignancies harboring ASXL1 mutations by blocking interactions between ASXL1 and associating epigenetic regulators. Here, we summarize the clinical implications of ASXL1 mutations, the role of wild-type ASXL1 in normal hematopoiesis, and oncogenic functions of mutant ASXL1 in myeloid neoplasms.

Relationship between Low Pretreatment Geriatric Nutritional Risk Index and Poor Tolerability of Azacitidine in Patients with Myelodysplastic Syndromes.

BACKGROUND: Predicting tolerability and treatment-related risks associated with azacitidine (AZA) in patients with myelodysplastic syndromes (MDS) before the initiation of therapy is required for appropriate treatment. Thus, in this study, the nutritional status of patients with MDS prior to AZA treatment was evaluated using the geriatric nutritional risk index (GNRI). Tolerability and overall survival (OS) after AZA initiation were also investigated. METHODS: This was a single-center retrospective observational study. A total of 59 patients with MDS treated with AZA were assessed using GNRI, and a comparison of undernourished (GNRI <92, n = 27) and non-undernourished (GNRI ≥92, n = 32) patients was performed. RESULTS: The undernourished group had a significant reduction in the number of patients that successfully completed 4 cycles of AZA treatment compared with the non-undernourished group (undernourished group, 11/27 patients, 40.7% vs. non-undernourished group, 24/32 patients, 75.0%; p = 0.009). Factors associated with the difference included karyotype and GNRI. There was also a significant increase in the rate of infectious complications in the undernourished group compared with the non-undernourished group (undernourished group, 33/60 cycles, 55.0% vs. non-undernourished group, 31/92 cycles, 33.7%; p = 0.012). Lastly, a significant reduction in OS was observed in the undernourished group compared with the non-undernourished group (undernourished group, 11.5 months; 95% CI, 5.2-16.7 vs. non-undernourished group, 21.9 months; 95% CI, 13.8-24.0; p = 0.026). Factors associated with OS included both the revised International Prognostic Scoring System (IPSS-R) and GNRI. CONCLUSIONS: These results indicate that predicting treatment completion and adverse events in patients with MDS prior to AZA treatment is important. This study suggests GNRI may be a valuable nutritional assessment tool for determining tolerability and OS of AZA treatment.

Prognostic Markers of Myelodysplastic Syndromes.

Myelodysplastic syndrome (MDS) is a clonal disease characterized by multilineage dysplasia, peripheral blood cytopenias, and a high risk of transformation to acute myeloid leukemia. In theory, from clonal hematopoiesis of indeterminate potential to hematologic malignancies, there is a complex interplay between genetic and epigenetic factors, including miRNA. In practice, karyotype analysis assigns patients to different prognostic groups, and mutations are often associated with a particular disease phenotype. Among myeloproliferative disorders, secondary MDS is a group of special entities with a typical spectrum of genetic mutations and cytogenetic rearrangements resembling those in de novo MDS. This overview analyzes the present prognostic systems of MDS and the most recent efforts in the search for genetic and epigenetic markers for the diagnosis and prognosis of MDS.

Anthropometric factors and risk of myeloid leukaemias and myelodysplastic syndromes: a prospective study and meta-analysis.

There is insufficient evidence linking excess body weight to risk of myeloid malignancies. We investigated this association using data from the Cancer Prevention Study-II (CPS-II), and a meta-analysis of published cohort studies. Among 152 090 CPS-II participants, 387 acute myeloid leukaemias (AML), 100 chronic myeloid leukaemias (CML) and 170 MDS were identified over 21 years of follow-up. In CPS-II, body mass index (BMI) was weakly associated with risk of CML (hazard ratio [HR] = 1·04, 95% confidence interval [CI]: 0·99-1·09 per 1 unit increase in BMI), AML (HR = 1·01, 95% CI: 0·98-1·03) and MDS (HR = 1·03, 95% CI: 0·99-1·07). After controlling for other anthropometric factors, no clear association was observed for height, BMI at age 18 years or weight change. In the meta-analysis (n = 7117 myeloid leukaemias), BMI 25-29·9 kg/m2 (HRpooled  = 1·36, 95% CI: 1·12-1·59) and BMI ≥30 kg/m2 (HRpooled  = 1·43, 95% CI: 1·18-1·69) were associated with higher risk of myeloid leukaemia overall, compared to a BMI <25 kg/m2 . Likewise, BMI ≥25 kg/m2 was positively associated with both AML and CML risk individually in the meta-analysis. These results underscore the need for large studies to detect associations with rare cancers, and show a modest, but positive association between excess body weight and myeloid malignancy risk.

Genetic abnormalities and pathophysiology of MDS.

Myelodysplastic syndromes (MDS) are a heterogeneous group of myeloid malignancies characterized by peripheral blood cytopenia and dishematopoiesis and frequently progress to acute myeloid leukemia. Genetic defects play a major role in pathogenesis of MDS, including cytogenetic abnormalities, gene mutations, and abnormal gene expression. Chromosomal abnormalities have been detected in approximately 50-60% of MDS patients, including the deletions of chromosome 5q and 7q, trisomy 8, and complex karyotypes. Newer genomic technologies, such as single-nucleotide polymorphism array and next-generation sequencing, revealed the heterozygous deletions resulting in haploinsufficient gene expression (e.g., CSNK1A1, DDX41 on chromosome 5, CUX1, LUC7L2, EZH2 on chromosome 7) involved in the pathogenesis of MDS. In addition, recurrent somatic mutations in more than 50 genes have been identified in 80-90% of MDS. The most recurrent genetic mutations are involved in the RNA splicing (e.g., SF3B1, SRSF2, U2AF1, ZRSR2, LUC7L2, DDX41) and epigenetic modifications, such as histone modification (e.g., ASXL1, EZH2) and DNA methylation (e.g., TET2, DNMT3A, IDH1/IDH2). TP53 mutation is associated with aggressive disease and frequently coincides with deletion of chromosome 5q. This review summarizes the recent progress in molecular pathogenesis of MDS. A better understanding of the specific subgroups of MDS patients will also aid in the development of new therapeutic approach for MDS.

A novel SAMD9 mutation causing MIRAGE syndrome: An expansion and review of phenotype, dysmorphology, and natural history.

Germline gain-of-function variants in SAMD9 have been associated with a high risk of mortality and a newly recognized constellation of symptoms described by the acronym MIRAGE: Myelodysplasia, Infection, Restriction of growth, Adrenal insufficiency, Genital phenotypes, and Enteropathy. Here, we describe two additional patients currently living with the syndrome, including one patient with a novel de novo variant for which we provide functional data supporting its pathogenicity. We discuss features of dysmorphology, contrasting with previously described patients as well as drawing attention to additional clinical features, dysautonomia and hearing loss that have not previously been reported. We detail both patients' courses following diagnosis, with attention to treatment plans and recommended specialist care. Our patients are the oldest known with arginine-substituting amino acid variants, and we conclude that early diagnosis and multidisciplinary management may positively impact outcomes for this vulnerable group of patients.

Myelodysplastic Syndromes Over Time: A Comparison of Two Patient Cohorts.

BACKGROUND: With advances in myelodysplastic syndromes (MDS), patient cohorts from different time periods might be different. OBJECTIVES: To compare presentation and outcomes between two cohorts. METHODS: Data were collected from George Washington University Medical Center, Washington, DC, USA 1986-1987 (DC), and Tel Aviv Medical Center, Israel 1999-2009 (TA). RESULTS: The study comprised 227 patients (139 TA, 88 DC). TA patients were older (75.4 ± 9.8 vs. 63.8 ± 14.3 years, P < 0.001) and had more cardiovascular diseases (56.8% vs. 14.8%, P < 0.001), fewer cytopenias (1.67 ± 0.82 vs. 2.0 ± 0.93, P = 0.003), and lower mean corpuscular volume (94.3 ± 9.9 fl vs. 100.5 ± 15.3 fl, P < 0.001). Hemoglobin, leukocyte, neutrophil, and platelet counts were similar. More TA patients had dysplasias. Bone marrow cellularity and cytogenetics were similar, but more TA patients had blasts < 5% (73.4% vs. 50.6%, P = 0.003). More TA patients had early French-American-British (FAB) disease (66.9% vs. 40.9%, P < 0.001) and lower risk disease per International Prognostic Scoring System (81% vs. 50%, P < 0.001). The 5 year survival (5YS) of TA patients was not significantly greater (62% vs. 55%). 5YS by FAB was also slightly greater for TA patients (77% vs. 65% for early FAB; 43% vs. 37% for advanced FAB, P > 0.05). CONCLUSIONS: Although patients diagnosed with MDS at a later period were older and had more cardiovascular co-morbidities, they had fewer cytopenias, tended to have earlier disease, and had minimally greater, but not significant, 5YS.

[Ineffective erythropoiesis in myelodysplastic syndrome].

Ineffective hematopoiesis is one of the hallmarks of myelodysplastic syndrome (MDS). Recently, several signaling pathways responsible for inefficient erythropoiesis in MDS have been uncovered. The p53-S100a8/S100a9-TLR4 pathway is involved in ineffective erythropoiesis in 5q minus (5q-) syndrome. Somatic mutations target multiple components of the messenger RNA (mRNA) splicing machinery including Splicing Factor 3 Subunit b1 (SF3b1) and Serine Arginine Rich Splicing Factor 2 (SRSF2) in patients with MDS. SF3b1 is the most frequently mutated spliceosome component in MDS and is mutated approximately 85% of the time in MDS with ring sideroblasts (MDS-RS). SF3b1 mutations are not simple loss-of-function or inactivating mutations but result in a change of function and cause aberrant splicing of genes that may be involved in the pathogenesis of MDS-RS. Recurrent mutations are also found in epigenetic regulator genes in MDS, including polycomb repressive complex 2 (PRC2) genes. The loss of enhancer of zeste homolog 2 (EZH2), an enzymatic component of PRC2 in mice, markedly accelerates the development of MDS in combination with representative driver mutations. The loss of EZH2 causes impaired erythropoiesis and increases ineffective hematopoiesis. Of interest, EZH2 is one of the targets of SRSF2 mutants in MDS, and mis-spliced EZH2 mRNA undergoes nonsense-mediated decay (NMD) -dependent degradation. All these data suggest that EZH2 insufficiency causes ineffective erythropoiesis.

Impact of anaemia on health-related quality of life and cardiac remodelling in patients with lower risk myelodysplastic syndromes. Results of GlobQoL study.

The aim of this study was to analyse the eventual changes in health-related quality of life (HRQoL) and left ventricular function (LVF) over a 1-year follow-up period in a cohort of patients with lower risk myelodysplastic syndromes (MDS) receiving standard supportive treatment, in order to identify potential clues for early clinical intervention, as well as to analyse how they relate to haemoglobin levels and other aspects of the disease. A total of 39 adult anaemic patients with lower risk MDS were included in a prospective, observational, multi-centre study. Changes in performance status, functional capacity and HRQoL were collected by using standardised measures (ECOG scale; SPPB, Short Physical Performance Battery; SF-36, Short-Form 36 questionnaire; QLQ-C30, Quality of Life Core Questionnaire; FACT-An, Functional Assessment of Cancer Therapy-Anaemia scale questionnaires respectively). Need for transfusion (Linear Analogue Scale Assessment), as perceived independently by the patient and the haematologist, was also recorded. No changes in HRQoL (or LVF) were found, except for slight reductions in SF-36 physical function (P = 0.034), SPPB gait speed (P = 0.038) and FACT-An score (P = 0.029), all without apparent immediate clinical relevance for HRQoL, that were unrelated to changes in haemoglobin level. Periodical evaluation of gait speed may assist the clinician in early detection of patient's occult functional decline before it becomes clinically relevant.

Extracellular vesicle miR-7977 is involved in hematopoietic dysfunction of mesenchymal stromal cells via poly(rC) binding protein 1 reduction in myeloid neoplasms.

The failure of normal hematopoiesis is observed in myeloid neoplasms. However, the precise mechanisms governing the replacement of normal hematopoietic stem cells in their niche by myeloid neoplasm stem cells have not yet been clarified. Primary acute myeloid leukemia and myelodysplastic syndrome cells induced aberrant expression of multiple hematopoietic factors including Jagged-1, stem cell factor and angiopoietin-1 in mesenchymal stem cells even in non-contact conditions, and this abnormality was reverted by extracellular vesicle inhibition. Importantly, the transfer of myeloid neoplasm-derived extracellular vesicles reduced the hematopoietic supportive capacity of mesenchymal stem cells. Analysis of extracellular vesicle microRNA indicated that several species, including miR-7977 from acute myeloid leukemia cells, were higher than those from normal CD34(+)cells. Remarkably, the copy number of miR-7977 in bone marrow interstitial fluid was elevated not only in acute myeloid leukemia, but also in myelodysplastic syndrome, as compared with lymphoma without bone marrow localization. The transfection of the miR-7977 mimic reduced the expression of the posttranscriptional regulator, poly(rC) binding protein 1, in mesenchymal stem cells. Moreover, the miR-7977 mimic induced aberrant reduction of hematopoietic growth factors in mesenchymal stem cells, resulting in decreased hematopoietic-supporting capacity of bone marrow CD34(+)cells. Furthermore, the reduction of hematopoietic growth factors including Jagged-1, stem cell factor and angiopoietin-1 were reverted by target protection of poly(rC) binding protein 1, suggesting that poly(rC) binding protein 1 could be involved in the stabilization of several growth factors. Thus, miR-7977 in extracellular vesicles may be a critical factor that induces failure of normal hematopoiesis via poly(rC) binding protein 1 suppression.