Advances in myelofibrosis: a clinical case approach

Renal extramedullary hematopoiesis as an epiphenomenon of bone marrow dysfunction in a patient with primary myelofibrosis: A rare case report

Extramedullary hematopoiesis represents a clinical compensatory condition characterized by the growth of hematopoietic tissue outside the bone marrow. It can mainly occur in patient with myeloproliferative disorders where alteration or neoplastic invasion of the bone marrow causes ineffective production of blood cells with the recruitment of progenitrix blood cells in non-hematopoietic organs, including kidneys. Renal extramedullary hematopoiesis is a rare condition manifesting as parenchymal or perirenal soft tissue masses with different patterns mimicking neoplasms, infectious or vascular diseases. We describe a unique case of a patient affected by primary myelofibrosis underwent ultrasound and magnetic resonance examinations showing bilateral perirenal alterations to be related to hemopoietic tissue. We also focused on the pathophysiology of this condition with imaging correlation. The case we present emphasises the importance of recognising the main radiological features of renal extramedullary hematopoiesis. MR examination should become part of the diagnostic pathway of the patient with primary myelofibrosis.

Detection of primary myelofibrosis in blood serum via Raman spectroscopy assisted by machine learning approaches; correlation with clinical diagnosis

Primary myelofibrosis (PM) is one of the myeloproliferative neoplasm, where stem cell-derived clonal neoplasms was noticed. Diagnosis of this disease is based on: physical examination, peripheral blood findings, bone marrow morphology, cytogenetics, and molecular markers. However, the molecular marker of PM, which is a mutation in the JAK2V617F gene, was observed also in other myeloproliferative neoplasms such as polycythemia vera and essential thrombocythemia. Therefore, there is a need to find methods that provide a marker unique to PM and allow for higher accuracy of PM diagnosis and consequently the treatment of the disease. Continuing, in this study, we used Raman spectroscopy, Principal Components Analysis (PCA), and Partial Least Squares (PLS) analysis as helpful diagnostic tools for PM. Consequently, we used serum collected from PM patients, which were classified using clinical parameters of PM such as the dynamic international prognostic scoring system (DIPSS) for primary myelofibrosis plus score, the JAK2V617F mutation, spleen size, bone marrow reticulin fibrosis degree and use of hydroxyurea drug features. Raman spectra showed higher amounts of C-H, C-C and C-C/C-N and amide II and lower amounts of amide I and vibrations of CH3 groups in PM patients than in healthy ones. Furthermore, shifts of amides II and I vibrations in PM patients were noticed. Machine learning methods were used to analyze Raman regions: (i) 800 cm-1 and 1800 cm-1, (ii) 1600 cm-1-1700 cm-1, and (iii) 2700 cm-1-3000 cm-1 showed 100 % accuracy, sensitivity, and specificity. Differences in the spectral dynamic showed that differences in the amide II and amide I regions were the most significant in distinguishing between PM and healthy subjects. Importantly, until now, the efficacy of Raman spectroscopy has not been established in clinical diagnostics of PM disease using the correlation between Raman spectra and PM clinical prognostic scoring. Continuing, our results showed the correlation between Raman signals and bone marrow fibrosis, as well as JAKV617F. Consequently, the results revealed that Raman spectroscopy has a high potential for use in medical laboratory diagnostics to quantify multiple biomarkers simultaneously, especially in the selected Raman regions.

Targeting Pim kinases in hematological cancers: molecular and clinical review

Decades of research has recognized a solid role for Pim kinases in lymphoproliferative disorders. Often up-regulated following JAK/STAT and tyrosine kinase receptor signaling, Pim kinases regulate cell proliferation, survival, metabolism, cellular trafficking and signaling. Targeting Pim kinases represents an interesting approach since knock-down of Pim kinases leads to non-fatal phenotypes in vivo suggesting clinical inhibition of Pim may have less side effects. In addition, the ATP binding site offers unique characteristics that can be used for the development of small inhibitors targeting one or all Pim isoforms. This review takes a closer look at Pim kinase expression and involvement in hematopoietic cancers. Current and past clinical trials and in vitro characterization of Pim kinase inhibitors are examined and future directions are discussed. Current studies suggest that Pim kinase inhibition may be most valuable when accompanied by multi-drug targeting therapy.

Sclt1 deficiency causes cystic kidney by activating ERK and STAT3 signaling

Ciliopathies form a group of inherited disorders sharing several clinical manifestations because of abnormal cilia formation or function, and few treatments have been successful against these disorders. Here, we report a mouse model with mutated Sclt1 gene, which encodes a centriole distal appendage protein important for ciliogenesis. Sodium channel and clathrin linker 1 (SCLT1) mutations were associated with the oral-facial-digital syndrome (OFD), an autosomal recessive ciliopathy. The Sclt1-/- mice exhibit typical ciliopathy phenotypes, including cystic kidney, cleft palate and polydactyly. Sclt1-loss decreases the number of cilia in kidney; increases proliferation and apoptosis of renal tubule epithelial cells; elevates protein kinase A, extracellular signal-regulated kinases, SMAD and signal transducer and activator of transcription 3 (STAT3) pathways; and enhances pro-inflammation and pro-fibrosis pathways with disease progression. Embryonic kidney cyst formation of Sclt1-/- mice was effectively reduced by an anti-STAT3 treatment using pyrimethamine. Overall, we reported a new mouse model for the OFD; and our data suggest that STAT3 inhibition may be a promising treatment for SCLT1-associated cystic kidney.

Identification of potential therapeutic target genes and miRNAs for primary myelofibrosis with microarray analysis

The aim of the present study was to identify potential therapeutic target genes and miRNAs for primary myelofibrosis (PMF). The dataset GSE53482 was downloaded from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) of peripheral blood (PB) cluster of differentiation (CD)34⁺ cells from PMF patients (PB-PMF group) and peripheral blood CD34⁺ cells from healthy individuals (PB-control group) were analyzed using the Linear Models for Microarray Data package in R. The Kyoto Encyclopedia of Genes and Genomes was used for pathway enrichment analysis. MiRNA-gene joint enrichment analysis was performed by ENViz and a miRNAs-gene regulatory network was constructed. A total of 1,182 DEGs (773 upregulated and 109 downregulated) and 48 DEMs (28 upregulated and 20 downregulated) were identified. According to the pathway enrichment analysis, a number of DEGs were enriched in metabolic pathways, including IDH1 and DNMT1. Other DEGs were enriched in the citrate cycle (tricarboxylic acid cycle; IDH1 and IDH3A) and certain DEGs were enriched in pyrimidine metabolism, including CARD8. For downregulated genes, certain DEGs were enriched in the spliceosome, including SF3B1 and CDC40. Furthermore, hsa-miR-127-3p, hsa-miR-140-3p and hsa-miR345 were associated with cell cycle-related biological processes, signal transduction and cell surface receptor signaling pathway. The DEM-DEG regulatory network indicated that hsa-miR-543 regulated 113 genes, including CARD8 and TIFA. The present study identified a number of genes, including IDH1, DNMT1, SF3B1 and CARD8, and miRNAs, including hsa-miR-127-3p and hsa-miR-140-3p, which may be therapeutic targets in the treatment of PMF.

Obstructive Uropathy as an Initial Presentation of Primary Myelofibrosis: Case Report and Review of Literature

Primary myelofibrosis (PMF) is a rare hematological disorder associated with progressive cytopenia and extra-medullary hematopoiesis. Acute kidney injury in this disease has been reported from diverse etiologies such as renal and peri-renal extramedullary hematopoiesis and tumor lysis syndrome. We report a patient who presented with obstructive uropathy from uric acid stones who was incidentally diagnosed with PMF during workup for persistent thrombocytosis and leukocytosis. Marrow histopathology was unique in presenting features of early PMF despite clinical picture mimicking essential thrombocythemia. Despite a common background of hyperuricemia in myeloproliferative neoplasms, AKI resulting from urate nephrolithiasis has seldom been reported in PMF. Published data on this association and clinical management is reviewed briefly.

P-Selectin Sustains Extramedullary Hematopoiesis in the Gata1 low Model of Myelofibrosis

Splenomegaly is a major manifestation of primary myelofibrosis (PMF) contributing to clinical symptoms and hematologic abnormalities. The spleen from PMF patients contains increased numbers of hematopoietic stem cells (HSC) and megakaryocytes (MK). These MK express high levels of P-selectin (P-sel) that, by triggering neutrophil emperipolesis, may cause TGF-β release and disease progression. This hypothesis was tested by deleting the P-sel gene in the myelofibrosis mouse model carrying the hypomorphic Gata1(low) mutation that induces megakaryocyte abnormalities that recapitulate those observed in PMF. P-sel(null) Gata1(low) mice survived splenectomy and lived 3 months longer than P-sel(WT) Gata1(low) littermates and expressed limited fibrosis and osteosclerosis in the marrow or splenomegaly. Furthermore, deletion of P-sel disrupted megakaryocyte/neutrophil interactions in spleen, reduced TGF-β content, and corrected the HSC distribution that in Gata1(low) mice, as in PMF patients, is abnormally expanded in spleen. Conversely, pharmacological inhibition of TGF-β reduced P-sel expression in MK and corrected HSC distribution. Spleens, but not marrow, of Gata1(low) mice contained numerous cKIT(pos) activated fibrocytes, probably of dendritic cell origin, whose membrane protrusions interacted with MK establishing niches hosting immature cKIT(pos) hematopoietic cells. These activated fibrocytes were not detected in spleens from P-sel(null) Gata1(low) or TGF-β-inhibited Gata1(low) littermates and were observed in spleen, but not in marrow, from PMF patients. Therefore, in Gata1(low) mice, and possibly in PMF, abnormal P-sel expression in MK may mediate the pathological cell interactions that increase TGF-β content in MK and favor establishment of a microenvironment that supports myelofibrosis-related HSC in spleen.

Recombinant interferon-α in myelofibrosis reduces bone marrow fibrosis, improves its morphology and is associated with clinical response

Recombinant interferon-α represents a well-established therapeutic option for the treatment of polycythemia vera and essential thrombocythemia. Recent studies also suggest a role for recombinant interferon-α in the treatment of 'early stage' primary myelofibrosis, but few studies have reported the bone marrow changes after clinically successful interferon therapy. The aim of the present study is to detail the histological responses to recombinant interferon-α in primary myelofibrosis and post-polycythemia vera/post-essential thrombocythemia myelofibrosis and to correlate these with clinical findings. We retrospectively studied 12 patients with primary myelofibrosis or post-polycythemia vera/post-essential thrombocythemia myelofibrosis, who had been treated with recombinant interferon-α. Six patients had received other prior cytoreductive therapies. Bone marrow biopsy was assessed for the following histological parameters: (i) cellularity; (ii) myeloid-to-erythroid ratio; (iii) megakaryocyte tight clusters; (iv) megakaryocyte and naked nuclei density; (v) megakaryocytic atypia; (vi) fibrosis; and (vii) the percentage of blasts. Clinical and laboratory data were included: (i) constitutional symptoms; (ii) splenomegaly, if present; and (iii) complete cell blood count. The clinical response to therapy was evaluated using the International Working Group for Myelofibrosis Research and Treatment/European LeukemiaNet response criteria. The Dynamic International Prognostic Scoring System (DIPSS) score was calculated before and after recombinant interferon-α administration. Successful interferon therapy for myelofibrosis was associated with a significant reduction of marrow fibrosis, cellularity, megakaryocyte density and naked nuclei density. The presence of JAK2(V617F) mutation correlated with improved DIPSS score. JAK2(V617F)-negative cases showed worsening of such score or evolution to acute myeloid leukemia. Cytogenetic analysis documented a normal karyotype in all cases. In conclusion, successful clinical response to interferon-α correlates well with an improvement of bone marrow morphology. The prognostic effect of such therapy may be influenced by the JAK2 mutational status. Additional studies are needed to confirm these preliminary data.

Genomic diversity in myeloproliferative neoplasms: focus on myelofibrosis

The classical myeloproliferative neoplasms (MPNs) are a group of clonal diseases comprising essential thrombocythaemia (ET), polycythaemia vera (PV) and primary myelofibrosis (PMF). PMF is the rarest disease sub type and has been challenging to address due to the lack of a specific genetic marker, inadequate risk identification models and a highly variable clinical course. Continuous efforts have over time, seen the inclusion of cytogenetic information in prognostic scoring models that have resulted in improved risk stratification models providing further rationale for therapeutic management. Technological advances using single nucleotide polymorphism arrays increased the detection of known and novel MPN related changes and variant detection by massively parallel sequencing provided a large scale screening tool for the multitude of somatic gene mutations that have more recently been described in MPN. Some of these mutations show an association with specific cytogenetic changes or phenotypes. While PMF occurs mainly in adults, it has also been described in paediatric cases and shows distinct histopathological, genetic and clinical features in comparison. This review provides an overview of the genomics landscape of PMF and current developments in MPN therapy.

Selective Janus associated kinase 1 inhibition as a therapeutic target in myelofibrosis

Hyperactive Janus associated kinase-signal transducers and activators of transcription (JAK-STAT) signaling has been shown to be integral to the pathogenesis of myelofibrosis (MF) regardless of the driver mutational status (JAK2V617F, JAK2 exon 12, MPL515L/K, CALR). Targeting of the JAK-STAT pathway has been the intense focus of therapeutic development and led to the approval of the JAK1/2 inhibitor, ruxolitinib. Despite the clear clinical success of ruxolitinib, dose limiting thrombocytopenia, treatment associated anemia and failure to effectively achieve bone marrow pathologic, cytogenetic and molecular remission remain shortcomings. JAK1 inhibition leads to depression in inflammatory cytokine expression associated with MF-related constitutional symptoms. The selective targeting of JAK1 may provide an opportunity to alleviate MF-related symptoms without anti-JAK2 therapy-related myelosuppression. Additionally, a JAK1 inhibitor may serve as an ideal candidate partner for combination therapeutic approaches in the treatment of MF. Current evaluation of selective JAK1 inhibition in MF will further clarify the relative contribution of aberrant JAK1 signaling to the pathogenesis of MF.

The JAK2 V617F mutational status and allele burden may be related with the risk of venous thromboembolic events in patients with Philadelphia-negative myeloproliferative neoplasms

INTRODUCTION

Patients with Philadelphia-negative myeloproliferative neoplasms (Ph(-) MPNs) are at increased risk of thromboembolic and hemorrhagic complications. The aim of the study was to determine the relationship between JAK2 V617F mutational status, JAK2 V617F allele burden and the risk of vascular complications occurrence.

MATERIALS AND METHODS

Analysis was performed in a cohort of 186 patients diagnosed with polycythemia vera (53), essential thrombocythemia (114), primary myelofibrosis (11), and unclassified MPN (8). The risk of vascular complications development was analyzed in 126 JAK2 V617F-positive patients with respect to allele burden assessed with allele-specific 'real-time' quantitative polymerase chain reaction (AS RQ-PCR).

RESULTS

Overall prevalence of any vascular complications was 44.6%. Arterial thrombosis occurred in 20.4%, venous thromboembolism (VTE) in 11.3%, bleeding episodes in 24.7% of patients. Individuals harboring JAK2 V617F mutation, regardless of MPN type, were at higher risk of VTE (OR=5.15, 95%CI: 1.16-22.90, P=0.024), mainly deep vein thrombosis (DVT). JAK2 allele burden higher than 20% identified patients with 7.4-fold increased risk of VTE (95%CI: 1.6-33.7, P=0.004), but not of arterial thrombosis, neither of bleeding complications, and remained the only significant VTE risk factor in multivariate logistic regression. High allele burdens (over 50%) were strikingly associated with proximal DVT cases, but not with distal DVT.

CONCLUSIONS

The group of MPN patients with JAK2 V617F allele burden higher than 20% may benefit the most from vigilant monitoring and appropriate prophylaxis against vascular events. Inclusion of JAK2 V617F mutant allele burden in new risk stratifications seems to be justified and requires controlled prospective trials.