Immune-dysregulation harnessing in myeloid neoplasms.

Myeloid malignancies arise in bone marrow microenvironments and shape these microenvironments in favor of malignant development. Immune suppression is one of the most important stages in myeloid leukemia progression. Leukemic clone expansion and immune dysregulation occur simultaneously in bone marrow microenvironments. Complex interactions emerge between normal immune system elements and leukemic clones in the bone marrow. In recent years, researchers have identified several of these pathological interactions. For instance, recent works shows that the secretion of inflammatory cytokines such as tumor necrosis factor-α (TNF-α), from bone marrow stromal cells contributes to immune dysregulation and the selective proliferation of JAK2V617F+ clones in myeloproliferative neoplasms. Moreover, inflammasome activation and sterile inflammation result in inflamed microenvironments and the development of myelodysplastic syndromes. Additional immune dysregulations, such as exhaustion of T and NK cells, an increase in regulatory T cells, and impairments in antigen presentation are common findings in myeloid malignancies. In this review, we discuss the role of altered bone marrow microenvironments in the induction of immune dysregulations that accompany myeloid malignancies. We also consider both current and novel therapeutic strategies to restore normal immune system function in the context of myeloid malignancies.

[Recent advances in bone marrow pathology for myeloproliferative neoplasms diagnosis].

Identification of driver genes and pathological bone marrow diagnosis were considered essential for subclassification of MPN in the revised 4th edition of the WHO classification, and this remained nearly unchanged in the 5th edition. Pathological diagnosis of primary myelofibrosis/pre-fibrotic stage by biopsy is now feasible and is becoming standardized. Progressive myelofibrosis and blast transformation are the advanced forms of MPN, and various therapeutic interventions for these forms have been devised. Observation of activated megakaryocytes on evaluation of megakaryocyte morphology could predict the progression of myelofibrosis. This paper describes recent progress in pathological diagnosis of MPN and how it is performed in practice.

[Clonal evolution in myeloproliferative neoplasms].

Recent advances in sequencing technologies have clarified the driver gene landscape in Philadelphia chromosomenegative (Ph-) myeloproliferative neoplasms (MPNs) and progressed understanding of MPN pathogenesis. Beyond mutations in the main three drivers of MPN, namely JAK2, MPL and CALR, somatic mutations in the epigenetic regulators and RNA splicing factors have been identified and their association with transformation to myelofibrosis and acute myeloid leukemia have been determined. Clonal expansion of hematopoietic cells with driver mutations (clonal hematopoiesis) has been detected in healthy individuals, especially in elderly people. In MPN patients, however, initial driver mutations such as those in JAK2 and DNMT3A have been shown to be acquired in utero or during childhood. In this review, I will summarize the recent findings about clonal evolution in MPN and the role of driver mutations.

Cytogenetics and genomics in CML and other myeloproliferative neoplasms.

Chronic myeloid leukemia is defined by the presence of the Philadelphia translocation t (9; 22) resulting in the BCR::ABL1 fusion. The other myeloproliferative neoplasms (MPN) subtypes also carry typical chromosomal abnormalities, which however are not pathognomonic for a specific entity of MPN. According to the WHO classification the distinction between these entities is still based on the integration of cytological, histopathological and molecular findings. Progression of CML into accelerated and blastic phase is usually driven by additional chromosome abnormalities and ABL1 kinase mutations. In the other MPN subtypes the additional mutations besides driver gene mutations in JAK2, MPL and CALR have a decisive impact on the propensity for progression. In addition, the sequence in which the driver mutations and risk conveying additional mutations have been acquired appears to play an important role. Here, we review cytogenetic and molecular changes in CML and MPN that should be evaluated during diagnosis and disease monitoring.

C-Mannosyl tryptophan is a novel biomarker for thrombocytosis of myeloproliferative neoplasms.

C-Mannosyl tryptophan (CMW), a unique glycosylated amino acid, is considered to be produced by degradation of C-mannosylated proteins in living organism. Although protein C-mannosylation is involved in the folding and secretion of substrate proteins, the pathophysiological function in the hematological system is still unclear. This study aimed to assess CMW in the human hematological disorders. The serum CMW levels of 94 healthy Japanese workers were quantified using hydrophilic interaction liquid chromatography. Platelet count was positively correlated with serum CMW levels. The clinical significance of CMW in thrombocytosis of myeloproliferative neoplasms (T-MPN) including essential thrombocythemia (ET) were investigated. The serum CMW levels of the 34 patients with T-MPN who presented with thrombocytosis were significantly higher than those of the 52 patients with control who had other hematological disorders. In patients with T-MPN, serum CMW levels were inversely correlated with anemia, which was related to myelofibrosis (MF). Bone marrow biopsy samples were obtained from 18 patients with ET, and serum CMW levels were simultaneously measured. Twelve patients with bone marrow fibrosis had significantly higher CMW levels than 6 patients without bone marrow fibrosis. Collectively, these results suggested that CMW could be a novel biomarker to predict MF progression in T-MPN.

TLR2 Derangements Likely Play a Significant Role in the Inflammatory Response and Thrombosis in Patients with Ph(-) Classical Myeloproliferative Neoplasm.

We investigated the role of toll-like receptors (TLRs) in inflammatory pathways in Philadelphia chromosome-negative myeloproliferative neoplasms (Ph(-)MPNs). TLR2 expression was increased in ET, PV, and MPN (grouped as (PV + (ET) + MF)), whereas TLR4 was elevated only in MPN. TLR3, 7, and 9 were not elevated. Cultured monocyte-derived dendritic cells and plasma assays in TLR2-elevated patients were found to secrete more cytokines than those from TLR2-normal patients. These facts suggest that TLR2 is the major inflammatory pathways in MPN. We also measured S100A9 and reactive oxygen species (ROS), revealing increased S100A9 in PV, MF, and MPN, while ROS were only increased in MF. These data suggests that MPNs initially involve TLR2, with minor contributions from TLR4, and with S100A9, leading to ROS formation, JAK2 mutation, and progression to MF or leukemia. Furthermore, patients with JAK2 mutations or leukocytosis exhibited higher TLR2 expression. In leukocyte-platelet interactions, cells from MPN patients displayed a stronger response to a TLR2 agonist than TLR4 agonist. A TLR2 inhibitor (but not a TLR4 inhibitor) attenuated this response. Thrombosis incidence was higher in TLR2-elevated patients (29%) than in TLR2-normal patients (19%). These findings suggest that TLR2 likely contributes to thrombosis in MPN.

Increased mRNA expression for serotonin receptor 1B (HTR1B) is associated with thrombosis in BCR::ABL1-negative myeloproliferative neoplasms.

BCR::ABL1-negative myeloproliferative neoplasms (MPNs) are clonal haematopoietic stem cell disorders characterized by specific driver mutations and an increased risk of both macrothrombosis and microthrombosis. Serotonin receptor type 1B (HTR1B) was found to be expressed by various solid tumours, and also primary bone marrow mononuclear cells from myelodysplastic neoplasm and acute myeloid leukaemia patients, representing a potential therapeutic target. In this study we assessed for the first time the expression levels of HTR1B mRNA in the peripheral blood mononuclear cells (PBMC) of 85 newly diagnosed MPN patients, consisting of 28 polycythemia vera, 25 essential thrombocythemia and 32 primary myelofibrosis cases. Levels of HTR1B expression between MPN subtypes and control group were not significantly different. However, at clinical data examination, it was observed that MPN patients with a recent history of major thrombosis and/or signs of impaired microcirculation exhibited significantly higher HTR1B expression levels compared to non-thrombotic MPNs and control group. Moreover, thrombotic MPN patients had significantly higher HTR1B expression than patients with recent thrombosis and absence of MPN diagnostic criteria. These findings suggest that increased levels of HTR1B expression in PBMC might be associated with thrombosis in MPN patients, but larger studies are needed for confirmation, including testing of the receptor protein expression level.

[Genetic Variation of SH2B3 in Patients with Myeloid Neoplasms].

OBJECTIVE: To observe the genetic variation of SH2B3 in patients with myeloid neoplasms. METHODS: The results of targeted DNA sequencing associated with myeloid neoplasms in the Department of Hematology, Xuanwu Hospital, Capital Medical University from November 2017 to November 2022 were retrospectively analyzed, and the patients with SH2B3 gene mutations were identified. The demographic and clinical data of these patients were collected, and characteristics of SH2B3 gene mutation, co-mutated genes and their correlations with diseases were analyzed. RESULTS: The sequencing results were obtained from 1 005 patients, in which 19 patients were detected with SH2B3 gene mutation, including 18 missense mutations (94.74%), 1 nonsense mutation (5.26%), and 10 patients with co-mutated genes (52.63%). Variant allele frequency (VAF) ranged from 0.03 to 0.66. The highest frequency mutation was p.Ile568Thr (5/19, 26.32%), with an average VAF of 0.49, involving 1 case of MDS/MPN-RS (with SF3B1 mutation), 1 case of MDS-U (with SF3B1 mutation), 1 case of aplastic anemia with PNH clone (with PIGA and KMT2A mutations), 2 cases of MDS-MLD (1 case with SETBP1 mutation). The other mutations included p.Ala567Thr in 2 cases (10.53%), p.Arg566Trp, p.Glu533Lys, p.Met437Arg, p.Arg425Cys, p.Glu314Lys, p.Arg308*, p.Gln294Glu, p.Arg282Gln, p.Arg175Gln, p.Gly86Cys, p.His55Asn and p.Gln54Pro in 1 case each. CONCLUSION: A wide distribution of genetic mutation sites and low recurrence of SH2B3 is observed in myeloid neoplasms, among of them, p.Ile568Thr mutation is detected with a higher incidence and often coexists with characteristic mutations of other diseases.

Mechanobiology and Primary Cilium in the Pathophysiology of Bone Marrow Myeloproliferative Diseases.

Philadelphia-Negative Myeloproliferative neoplasms (MPNs) are a diverse group of blood cancers leading to excessive production of mature blood cells. These chronic diseases, including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), can significantly impact patient quality of life and are still incurable in the vast majority of the cases. This review examines the mechanobiology within a bone marrow niche, emphasizing the role of mechanical cues and the primary cilium in the pathophysiology of MPNs. It discusses the influence of extracellular matrix components, cell-cell and cell-matrix interactions, and mechanosensitive structures on hematopoietic stem cell (HSC) behavior and disease progression. Additionally, the potential implications of the primary cilium as a chemo- and mechanosensory organelle in bone marrow cells are explored, highlighting its involvement in signaling pathways crucial for hematopoietic regulation. This review proposes future research directions to better understand the dysregulated bone marrow niche in MPNs and to identify novel therapeutic targets.

Myeloproliferative neoplasms: young patients, current data and future considerations.

The Philadelphia-negative chronic myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell disorders predominantly occurring in elderly, whereas in children and young adults are quite infrequent. Therefore, less is known about clinical presentation, genetic abnormalities, prognosis and best management strategies for this groups of patients. Currently, more cases of younger MPN patients are diagnosed. Nevertheless, diagnosis of MPNs, especially in childhood, may be difficult due to lower incidence of JAK2V617F and CALR mutations and differences in peripheral blood counts between adults and children. Challenges for younger MPN patients are longer life expectances, specific psychosocial need, fertility and pregnancy need and a long term therapy side effect (including second cancers). The most severe MPNs complication is transformation to secondary myelofibrosis (MF) or acute myeloid leukemia (AML). Optimal management of young MPNs remains a challenge as the classical risk scores fail in young MPNs. Moreover, the main objective of young MPNs therapy should be the disease outcome modification. Therefore, international collaborative work between pediatricians and "adult hematologists" is required to measure outcomes and generate protocol of management of young MPNs.

[Risk Prediction and Risk Factors of Thrombotic/Bleeding Events in Patients with Myeloproliferative Neoplasm].

OBJECTIVE: To analyze the clinical characteristics and occurrence of thrombotic/bleeding events of patients with myeloproliferative neoplasm (MPN), and explore the main influencing factors, and create a risk prediction. METHODS: The clinical data of 126 MPN patients with BCR-ABL fusion gene negative in the Department of Hematology of Gansu Provincial Hospital from January 2016 to September 2021 were collected, and their clinical characteristics, occurrence of thrombotic/bleeding events and main influencing factors were analyzed and summarized retrospectively. Then, a risk prediction model for thrombotic/bleeding events in MPN patients was constructed. RESULTS: Among 126 MPN patients, 50 patients (39.7%) had experienced thrombotic/bleeding events, including 44 patients (34.9%) with thrombotic events and 6 patients (4.8%) with bleeding events. Among thrombotic diseases, cerebral thrombosis was the most common (23/44, 52.3%), followed by 9 cases of limb artery thrombosis mainly characterized by finger and toe tip artery ischemia, occlusion and gangrene (9/44, 20.5%). Bleeding events included intracerebral hemorrhage and gastrointestinal hemorrhage. Univariate analysis showed that hypertension, hyperhomocysteinemia, white blood cell (WBC) ≥10×109/L, hematocrit (HCT) ≥49%, platelet (PLT) ≥600×109/L and JAK2V617F gene mutation were risk factors for thrombotic/bleeding events in MPN patients, while CALR gene mutation was a protective factor. Multivariate analysis showed that hypertension and PLT≥600×109/L were independent risk factors for thrombotic/bleeding events in MPN patients. The goodness of fit of the constructed risk prediction model was 0.872, and the area under the ROC curve was 0.838. The model was validated with clinical data, the sensitivity, specificity and accuracy was 78.85%, 87.83% and 84.13%, respectively . CONCLUSION: The risk of thrombotic/bleeding events in MPN patients with high WBC count, hypertension and hyperhomocysteinemia is higher. Controlling hypertension and hyperhomocysteinemia and reducing WBC and PLT counts are helpful to prevent thrombotic/bleeding events and improve the life quality of patients.

DARS expression in BCR/ABL1-negative myeloproliferative neoplasms and its association with the immune microenvironment.

DARS, encoding for aspartyl-tRNA synthetase, is implicated in the pathogenesis of various cancers, including renal cell carcinoma, glioblastoma, colon cancer, and gastric cancer. Its role in BCR/ABL1-negative myeloproliferative neoplasms (MPNs), however, remains unexplored. This study aimed to elucidate the expression of DARS in patients with MPNs (PV 23, ET 19, PMF 16) through immunohistochemical analysis and to examine the profiles of circulating immune cells and cytokines using flow cytometry. Our findings indicate a significant overexpression of DARS in all MPNs subtypes at the protein level compared to controls (P < 0.05). Notably, elevated DARS expression was linked to splenomegaly in MPNs patients. The expression of DARS showed a negative correlation with CD4+ T cells (R = - 0.451, P = 0.0004) and CD4+ T/CD8+ T cell ratio (R = - 0.3758, P = 0.0040), as well as with CD68+ tumor-associated macrophages (R = 0.4037, P = 0.0017). Conversely, it was positively correlated with IL-2 (R = 0.5419, P < 0.001), IL-5 (R = 0.3161, P = 0.0166), IL-6 (R = 0.2992, P = 0.0238), and IFN-γ (R = 0.3873, P = 0.0029). These findings underscore a significant association between DARS expression in MPNs patients and specific clinical characteristics, as well as immune cell composition. Further investigation into the interplay between DARS and the immune microenvironment in MPNs could shed light on the underlying mechanisms of MPNs pathogenesis and immune dysregulation.

The impact of next-generation sequencing for diagnosis and disease understanding of myeloid malignancies.

INTRODUCTION: Defining the chromosomal and molecular changes associated with myeloid neoplasms (MNs) optimizes clinical care through improved diagnosis, prognosis, treatment planning, and patient monitoring. This review will concisely describe the techniques used to profile MNs clinically today, with descriptions of challenges and emerging approaches that may soon become standard-of-care. AREAS COVERED: In this review, the authors discuss molecular assessment of MNs using non-sequencing techniques, including conventional cytogenetic analysis, fluorescence in situ hybridization, chromosomal genomic microarray testing; as well as DNA- or RNA-based next-generation sequencing (NGS) assays; and sequential monitoring via digital PCR or measurable residual disease assays. The authors explain why distinguishing somatic from germline alleles is critical for optimal management. Finally, they introduce emerging technologies, such as long-read, whole exome/genome, and single-cell sequencing, which are reserved for research purposes currently but will become clinical tests soon. EXPERT OPINION: The authors describe challenges to the adoption of comprehensive genomic tests for those in resource-constrained environments and for inclusion into clinical trials. In the future, all aspects of patient care will likely be influenced by the adaptation of artificial intelligence and mathematical modeling, fueled by rapid advances in telecommunications.

Myeloproliferative Neoplasms Transcriptome Reveals Pro-Inflammatory Signature and Enrichment in Peripheral Blood Monocyte-Related Genes.

Myeloproliferative neoplasms (MPN) are hematological diseases associated with genetic driver mutations in the JAK2, CALR, and MPL genes and exacerbated oncoinflammatory status. Analyzing public microarray data from polycythemia vera (n = 41), essential thrombocythemia (n = 21), and primary myelofibrosis (n = 9) patients' peripheral blood by in silico approaches, we found that pro-inflammatory and monocyte-related genes were differentially expressed in MPN patients' transcriptome. Genes related to cell activation, secretion of pro-inflammatory and pro-angiogenic mediators, activation of neutrophils and platelets, coagulation, and interferon pathway were upregulated in monocytes compared to controls. Together, our results suggest that molecular alterations in monocytes may contribute to oncoinflammation in MPN.

Regulation of STAT5 phosphorylation and interaction with SHP1 by lnc-AC004893, a long non-coding RNA overexpressed in myeloproliferative neoplasms.

OBJECTIVES: Constitutive activation of Janus kinase 2 (JAK2)/signal transducer and activator of transcription (STAT) signaling pathway is central to the pathogenesis of myeloproliferative neoplasms (MPNs). Long noncoding RNAs (lncRNAs) regulate diverse biological processes. However, the role of lncRNAs in MPN pathogenesis is not well studied. METHODS: The expression of lnc-AC004893 in MPN patients was measured by quantitative real-time PCR (qRT-PCR). Gene-specific short hairpin RNAs (shRNAs) were designed to inhibit the expression of lnc-AC004893, and western blot was performed to explore the role of lnc-AC004893 via regulating the JAK2/STAT5 signaling pathway. Furthermore, co-IP was performed to determine the binding ability of lnc-AC004893 and STAT5 protein. Finally, the BaF3-JAK2V617F-transplanted mouse model was used to assess the biological role of lnc-ac004893 in vivo. RESULTS: We report that lnc-AC004893, a poorly conserved pseudogene-209, is substantially upregulated in MPN cells compared with normal controls (NCs). Knockdown of lnc-AC004893 by specific shRNAs suppressed cell proliferation and decreased colony formation. Furthermore, the knockdown of lnc-AC004893 reduced the expression of p-STAT5 but not total STAT5 in HEL and murine IL-3-dependent Ba/F3 cells, which present constitutive and inducible activation of JAK2/STAT5 signaling. In addition, inhibition of murine lnc-ac004893 attenuated BaF3-JAK2V617F-transplanted phenotypes and extended the overall survival. Mechanistically, knockdown of lnc-AC004893 enhanced the binding ability of STAT5 and protein tyrosine phosphatase SHP1. Furthermore, knockdown of lnc-AC004893 decreased STAT5-lnc-AC004893 interaction but not SHP1-lnc-AC004893 interaction. CONCLUSION: Lnc-AC004893 regulates STAT5 phosphorylation by affecting the interaction of STAT5 and SHP1. Lnc-AC004893 might be a potential therapeutic target for MPN patients.

Liver and spleen shear-wave elastography in the diagnosis and severity staging of myeloproliferative diseases and myelofibrosis.

AIMS: Spleen and liver stiffness, investigated by VCTE (Vibration-Controlled Transient Elastography), have been associated with marrow fibrosis in patients with myeloproliferative neoplasms (MPNs). Tissue stiffness can be assessed by shear wave point (pSWE) and bidimensional elastography (2DSWE). Spleen stiffness (SS) values were higher in Myelofibrosis (MF) and Polycythemia Vera (PV) compared to Essential Thrombocythemia (ET). We aimed to identify SWE differences between MPN patients and healthy volunteers; to evaluate specific SWE features in patients with MF, PV and ET; to establish a correlation with bone marrow fibrosis in patients with myeloproliferative disease. METHODS: Patients with myeloproliferative disease and healthy volunteers performed evaluation of spleen and liver stiffness (LS) by pSWE and 2DSWE. RESULTS: A total of 218 subjects were included: 143 with myeloproliferative disease (64 MF, 29.4%, 33 PV, 15.1% and 46 ET, 21.1%), and 75 (34.4%) healthy volunteers. Compared to volunteers, MF patients had greater spleen (pSWE 40.9 vs. 26.3 kPa, p < 0.001; 2DSWE 34.9 vs. 20.1 kPa, p < 0.001), and liver stiffness (pSWE 7.72 vs. 5.52 kPa, p < 0.001; 2DSWE 6.96 vs. 5.01 kPa, p < 0.001). In low (0-1) (n = 81, 60.4%) versus high-grade bone marrow fibrosis (2-3) (n = 42, 39.6%), is evident a higher median stiffness in patients with higher grades of fibrosis both for liver (pSWE 5.2 vs. 6.65 kPa; 2DSWE 5.1 vs. 6.05 kPa) and spleen (pSWE 27.2 vs. 37.9 kPa, 2DSWE 21.7 vs 30.75 kPa-p < 0.001 in both). CONCLUSION: SWE evaluation distinguishes MF patients from HV and ET/PV and may help in MPN diagnosis. LS and SS values are associated with bone marrow fibrosis grade.

Advances with janus kinase inhibitors for the treatment of myeloproliferative neoplasms: an update of the literature.

INTRODUCTION: The hallmark discovery of hyperactivation of the janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway was a sentinel moment in the history of myeloproliferative neoplasms (MPNs). This finding paved the way for the development of JAK inhibitors, which now represent the foundation of myelofibrosis therapy. With four JAK inhibitors now approved for myelofibrosis, awareness of their clinical efficacy and safety data and recognition of their unique pharmacologic attributes are of critical importance. Additionally, ruxolitinib represents an integral part of the therapeutic arsenal for polycythemia vera. AREAS COVERED: This review provides a broad overview of the published literature supporting JAK inhibitor therapy for MPNs. Primarily focusing on myelofibrosis, each of the four available JAK inhibitors is reviewed in detail, including pharmacology, efficacy, and safety data. Failure of JAK inhibitors and future directions in JAK inhibitor therapy are also discussed. EXPERT OPINION: JAK inhibitors revolutionized the treatment of MPNs and have dramatically improved patient outcomes. However, data informing selection between currently available JAK inhibitors is limited. These agents are not curative and eventually fail most patients with myelofibrosis. Combining JAK inhibitors with novel targeted agents appears to be the most promising path to further improve outcomes.

A comparison of WHO-5 and ICC classifications in a series of myeloid neoplasms, considerations for hematopathologists and molecular pathologists.

OBJECTIVES: The International Consensus Classification (ICC) and 5th Edition of the World Health Organization Classification (WHO-5) made substantive updates to the classification of myeloid neoplasms. This study compares the systems in a series of myeloid neoplasms with increased blasts, analyzing implications for diagnostic workflow and reporting. METHODS: Bone marrow biopsies categorized as myelodysplastic syndrome with excess blasts (MDS-EB) or acute myeloid leukemia (AML) by WHO-R4 were identified. Results of morphology review, karyotype, fluorescence in situ hybridization, and next-generation sequencing were compiled. Cases were retrospectively re-classified by WHO-5 and ICC. RESULTS: 46 cases were reviewed. 28 cases (61 %) had ≥20 % blasts, with the remaining cases having 5-19.5 % blasts. The most common differences in classification were 1) the designation of MDS versus MDS/AML (10/46, 22 %) for cases with 10-19 % blasts and 2) the ICC's designation of TP53 variants as a separate classifier for AML (8/46, 17 %). Bi-allelic/multi-hit TP53 alterations were identified in 15 cases (33 %). Variants of potential germline significance were identified in 29 (63 %) cases. CONCLUSIONS: While terminology differences between WHO-5 and ICC exist, both systems invoke similar opportunities for improved reporting: standardized classification of pathogenic variants (notably TP53), streamlined systems to evaluate for potential germline variants, and integrated reporting of morphologic and genetic data.