JAK2, CALR, MPL, and ASXL1 Mutations in 136 Thai Patients with Philadelphia-Negative Myeloproliferative Neoplasms and Their Correlations with Clinical Outcomes

Background: Philadelphia chromosome (Ph)-negative myeloproliferative neoplasms (MPN) are a group of hematological malignancies, including polycythemia vera (PV), essential thrombocytosis (ET), and primary myelofibrosis (PMF). Mutations of JAK2, CALR, MPL, and ASXL1 are associated with carcinogenesis and clinical characteristics of Ph-negative MPN. However, the availability of the data regarding these mutations is relatively limited in Thai population. Objective: To investigate these mutations in Thai Ph-negative MPN patients. Materials and Methods: One hundred thirty-six MPN (48 PV, 72 ET, and 16 PMF) cases were enrolled. Mutations of JAK2 V617F and MPL W515L/K mutations were investigated using allele-specific PCR (AS-PCR) and confirmed by sequencing. CALR and ASXL1 mutations were investigated using Sanger sequencing. Results: The JAK2 V617F mutation was detected in 83.3% of PV, 66.6% of ET, and 50.0% of PMF, and correlated with higher RBC, WBC, and PLT counts in PV. CALR mutations were detected in 16.7% of ET and 12.5% of PMF and associated with a higher PLT count in ET. The MPL W515L mutation was detected in one PMF patient. ASXL1 mutations were detected in 6.3% of PV, 8.3% of ET, and 12.4% of PMF, with c.1954G>A being the preponderant mutational form. ASXL1 mutations increased the risk (RR 27.6) and accelerated the onset of AML transformation. Conclusion: The present study provided the prevalence and clinical correlation of JAK2, CALR, MPL, and ASXL1 mutations among Thai Ph-negative MPN patients. The association of ASXL1 mutations with adverse clinical outcomes suggested the potential usefulness of these mutations as a prognostic marker for Ph-negative MPN patients. Keywords: JAK2, MPL, CALR, ASXL1, Thai, Philadelphia-negative myeloproliferative neoplasm (MPN)

Download Full-text

Calreticulin and JAK2 Exon 12 Mutation Screening in Patients with Myeloproliferative Neoplasms’ in Jeddah Region, Saudi Arabia

Journal of Pharmaceutical Research International ◽

10.9734/jpri/2021/v33i47a33029 ◽

2021 ◽

pp. 420-428

Author(s):

Heba Alkhatabi ◽

Heyam Abdulqayoom ◽

Raed Alserihi ◽

Raed Felimban ◽

Aisha Elaimi ◽

...

Keyword(s):

Myeloproliferative Neoplasms ◽

Direct Sequencing ◽

Mutation Screening ◽

Jak2 V617f ◽

Primary Myelofibrosis ◽

Pcr Analysis ◽

Allele Specific ◽

Pcr Method ◽

Calr Mutations ◽

The Impact

Background: The JAK2 V617F mutation’s discovery has largely facilitated the comprehension of the myeloproliferative neoplasms’(MPNs) pathogenesis. In recent times, calreticulin (CALR) mutations have been detected in patients with JAK2V617F negative primary myelofibrosis (PMF), and essential thrombocythemia (ET). Methods: This study analyzed the impact of JAK 2 Exon 12 and CALR common mutations in 65 patients with JAK2V617F negative MPN from the Jeddah region. An allele-specific polymerase chain reaction (PCR) method was used to screen four common mutations on Exon 12 and direct sequencing and PCR analysis were utilized to screen all patients for CALR. Results: None of the patients were positive for the Exon 12 mutation and eight patients were positive for CALR mutations. Conclusions: This is the first Saudi Arabian research that focused on screening CALR hotspot mutations and this mutation exists. This fact highlights the importance of implementing diagnostic screening of CALR on MPN patients, in general, and patients with high platelet count, in particular. Further screening of other predisposing genetic markers might facilitate the identification of an important genetic variant, which could aid in the understanding of disease pathogenesis.

Download Full-text

Clinical and Laboratory Features of JAK2 V617F, CALR, and MPL Mutations in Malaysian Patients with Classical Myeloproliferative Neoplasm (MPN)

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18147582 ◽

2021 ◽

Vol 18 (14) ◽

pp. 7582

Author(s):

Razan Hayati Zulkeflee ◽

Zefarina Zulkafli ◽

Muhammad Farid Johan ◽

Azlan Husin ◽

Md Asiful Islam ◽

...

Keyword(s):

Thrombotic Event ◽

Myeloproliferative Neoplasm ◽

Jak2 V617f ◽

Primary Myelofibrosis ◽

Genetic Profile ◽

Allele Specific ◽

Exon 9 ◽

Calr Mutations

Mutations of JAK2V617F, CALR, and MPL genes confirm the diagnosis of myeloproliferative neoplasm (MPN). This study aims to determine the genetic profile of JAK2V617F, CALR exon 9 Type 1 (52 bp deletion) and Type 2 (5 bp insertion), and MPL W515 L/K genes among Malaysian patients and correlate these mutations with clinical and hematologic parameters in MPN. Mutations of JAK2V617F, CALR, and MPL were analyzed in 159 Malaysian patients using allele-specific polymerase chain reaction, including 76 polycythemia vera (PV), 41 essential thrombocythemia (ET), and 42 primary myelofibrosis (PMF) mutations, and the demographics of the patients were retrieved. The result showed that 73.6% JAK2V617F, 5.66% CALR, and 27.7% were triple-negative mutations. No MPL W515L/K mutation was detected. In ET and PMF, the predominance type was the CALR Type 1 mutation. In JAK2V617F mutant patients, serum LDH was significantly higher in PMF compared to PV and ET. PV has a higher risk of evolving to post PV myelofibrosis compared to ET. A thrombotic event at initial diagnosis of 40.9% was high compared to global incidence. Only one PMF patient had a CALR mutation that transformed to acute myeloid leukemia. JAK2V617F and CALR mutations play an important role in diagnostics. Hence, every patient suspected of having a myeloproliferative neoplasm should be screened for these mutations.

Download Full-text

In-Frame Exon 9 CALR Deletions Co-Occur with Other Alterations in the JAK-STAT Pathway in Myeloproliferative Neoplasms

Blood ◽

10.1182/blood.v124.21.4588.4588 ◽

2014 ◽

Vol 124 (21) ◽

pp. 4588-4588 ◽

Cited By ~ 2

Author(s):

Yongbao Wang ◽

Albert K Ho ◽

Qiulu Pan ◽

Frederick Karl Racke ◽

Dan Jones

Keyword(s):

Mutation Analysis ◽

Somatic Mutations ◽

Myeloproliferative Neoplasms ◽

Myeloproliferative Neoplasm ◽

Point Mutations ◽

Jak2 V617f ◽

Illumina Miseq ◽

Primary Myelofibrosis ◽

Ensembl Database ◽

Stat Pathway

Abstract Introduction: Mutations in the chaperone gene calreticulin (CALR) have been recently identified in essential thrombocythemia (ET) and primary myelofibrosis (PMF), and are essentially mutually exclusive with JAK2 or MPL mutations. Normal and mutant CALR proteins may differentially affect the subcellular trafficking of JAK-STAT signaling components. CALR mutations previously reported in ET and PMF have been +1 frameshift (fs) mutations localized to exon (E) 9 that generate a novel C-terminal protein sequence with a shift from acidic to basic residues. CALR E9 in-frame (IF) deletions have been recently rarely reported as polymorphisms such as TMP_ESP_19_13054686_13054688 and TMP_ESP_19_13054650_13054658 (Ensembl database entries). We sought to determine the frequency and associated clinical features of CALR with E9 IF alterations in samples submitted for suspicion of a myeloproliferative neoplasm (sMPN). We also assessed whether CALR IF alterations are differentially associated with +1fs mutations or with JAK2 V617For other somatic mutations in MPN-associated genes. Materials and Methods: CALR mutation analysis of E9 was performed on genomic DNA extracted from blood, bone marrow (BM) aspirate or fixed BM biopsy sections using a Sanger sequencing assay with an analytic sensitivity of at least 15%. E9 IF cases were further assessed and mutations quantified by an Ion torrent sequencing panel assessing CALR, CSF3R, JAK2 and MPL, a second panel containing ASXL1, EZH2, IDH1, IDH2, KRAS, NRAS and TET2 and an Illumina MiSeq extended panel with 20 additional MPN-associated genes. These assays had a sensitivity of approximately 5%. JAK2 V617Fmutations were quantitated using a pyrosequencing assay with an analytic sensitivity of 1%. Results: We assessed CALR E9 mutation status in 733 sMPN samples that were negative for JAK2 V617F mutation. 148 (20.1%) had typical +1fs mutations (95 type 1 and variants, 53 type 2 and variants); 2 (0.3%) had point mutations (E381A and D7373M); 7 (1.0%) had IF deletions including E381_A382>A, D397_D400>D (n =4), D400_K401>D and E405_V409>V. All E9 IF deletions were present at ~50% of reads. Clinical diagnoses were cytopenia/BM fibrosis, ET, thrombocytosis/anemia, and sMPN unspecified. Mutation analysis for 27 additional MPN-associated genes revealed mutations in 5/7 (71.4%) IF deletion cases including in MPL (W515L,40%; D163Y,12%), CSF3R (A470T 46%), ASXL1 (D954fs*26, 45%) and ZRSR2 (S449_R450dup, 27%). No additional mutations were found in the 2 cases with non-synonymous CALR point mutations/SNPs. In a parallel set of 76 MPN samples that had JAK2 V617F at varying levels, we noted 1 E9 IF deletion (D397_D400>D) in a sMPN case with 21.6% JAK2 V617F, and a typical +1fs mutation (K385fs*47) in a case with low (4.2%) JAK2 V617F. All other JAK2 V617F cases had no E9 CALR alterations. Conclusions: CALR E9 in-frame deletions occur in up to 1% of sMPN samples and involve a variety of codons in the acidic domain. Therefore, sizing assays without DNA sequencing are not sufficient to unequivocally distinguish IF deletions from the characteristic +1 frameshift somatic mutations associated with ET and PMF. Given their level, these CALR IF deletions are likely germline sequence variants but are associated with a high frequency of somatic mutations in other MPN-associated genes but not with CALR +1fs mutations. Their co-occurrence with pathogenic somatic mutations in JAK2, MPL and CSF3R affecting the JAK-STAT pathway raises the possibility for a contributory role of altered CALR proteins produced by these E9 deletions in the pathogenesis of MPN. Disclosures Wang: Quest Diagnostics: Employment. Ho:Quest Diagnostics: Employment. Pan:Quest Diagnostics: Employment. Racke:Quest Diagnostics: Employment. Jones:Quest Diagnostics: Employment.

Download Full-text

STAT5 is Expressed in CD34+/CD38− Stem Cells and Serves as a Potential Molecular Target in Ph-Negative Myeloproliferative Neoplasms

Cancers ◽

10.3390/cancers12041021 ◽

2020 ◽

Vol 12 (4) ◽

pp. 1021 ◽

Cited By ~ 3

Author(s):

Emir Hadzijusufovic ◽

Alexandra Keller ◽

Daniela Berger ◽

Georg Greiner ◽

Bettina Wingelhofer ◽

...

Keyword(s):

Stem Cells ◽

Myeloproliferative Neoplasms ◽

Jak2 V617f ◽

Primary Myelofibrosis ◽

Janus Kinase ◽

Signaling Cascades ◽

Nuclear Compartment ◽

Downstream Signaling ◽

Direct Targeting ◽

Calr Mutations

Janus kinase 2 (JAK2) and signal transducer and activator of transcription-5 (STAT5) play a key role in the pathogenesis of myeloproliferative neoplasms (MPN). In most patients, JAK2 V617F or CALR mutations are found and lead to activation of various downstream signaling cascades and molecules, including STAT5. We examined the presence and distribution of phosphorylated (p) STAT5 in neoplastic cells in patients with MPN, including polycythemia vera (PV, n = 10), essential thrombocythemia (ET, n = 15) and primary myelofibrosis (PMF, n = 9), and in the JAK2 V617F-positive cell lines HEL and SET-2. As assessed by immunohistochemistry, MPN cells displayed pSTAT5 in all patients examined. Phosphorylated STAT5 was also detected in putative CD34+/CD38− MPN stem cells (MPN-SC) by flow cytometry. Immunostaining experiments and Western blotting demonstrated pSTAT5 expression in both the cytoplasmic and nuclear compartment of MPN cells. Confirming previous studies, we also found that JAK2-targeting drugs counteract the expression of pSTAT5 and growth in HEL and SET-2 cells. Growth-inhibition of MPN cells was also induced by the STAT5-targeting drugs piceatannol, pimozide, AC-3-019 and AC-4-130. Together, we show that CD34+/CD38− MPN-SC express pSTAT5 and that pSTAT5 is expressed in the nuclear and cytoplasmic compartment of MPN cells. Whether direct targeting of pSTAT5 in MPN-SC is efficacious in MPN patients remains unknown.

Download Full-text

A Case Report on Coexisting JAK2 V617F and Calr exon 9 Mutation in Essential Thrombocythemia

Blood ◽

10.1182/blood.v126.23.5215.5215 ◽

2015 ◽

Vol 126 (23) ◽

pp. 5215-5215

Author(s):

Munazza Rashid ◽

Rifat Zubair Ahmed ◽

Shariq Ahmed ◽

Muhammad Nadeem ◽

Nuzhat Ahmed ◽

...

Keyword(s):

Essential Thrombocythemia ◽

Conflicts Of Interest ◽

Myeloproliferative Neoplasms ◽

Diagnostic Algorithm ◽

Jak2 V617f ◽

Primary Myelofibrosis ◽

Common Mutation ◽

Hypochondriac Region ◽

Exon 9 ◽

Calr Mutations

Abstract Myeloproliferative Neoplasms (MPNs) are a heterogeneous group of clonal disorders derived from multipotent hematopoietic myeloid progenitors. Classic "BCR-ABL1-negative" MPNs is an operational sub-category of MPNs that includes polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). These three disorders are characterized by stem cell-derived clonal myeloproliferation. The most common mutation in the MPNs PV, ET and PMF is JAK2 V617F. JAK2 V617F can be detected in about 95% of patients with PV while remaining 5% of PV patients carry a somatic mutation of JAK2 exon 12. Approximately one third of patients with ET or PMF do not carryany mutation in JAK2 or MPL. In December 2013 mutations were described in calreticulin (CALR) gene in 67-71% and 56-88% of JAK2 V617F and MPL negative patients with ET and PMF, respectively. Since this discovery, CALR mutations have not only been recommended to be included in the diagnostic algorithm for MPNs, but also CALR exon 9 mutations have been recognised to have clinical utility as mutated patients have a better outcome than JAK2 V617F positive patients.CALR mutations have also been reported to be mutually exclusive with JAK2 V617F or MPL mutations. According to our knowledge so farthere have been only six reports published,which described patients harbouring concurrent JAK2 V617F and CALR exon 9 mutations; seven ET, three PMF, one PV and one MPN-U. In the present study we are reporting ET patient with coexisting JAK2 V617F and CALR exon 9 mutations from our center. In July 2011, 55-years-old female patient was referred to our hospital with a history of gradual elevation of platelet counts accompanied with pain in right hypochondriac region and feet. Bone Marrow aspirate consisted of 'Stag-horn' appearance Megakarocytes. Multiple platelets aggregates and islands were seen throughout the aspirate smear. ARMS-PCR for JAK2 V617F mutation was positive whereas bidirectional Sanger sequencing for CALR exon 9 exhibited c.1214_1225del12 (p.E405_D408del) mutation pattern. Disclosures No relevant conflicts of interest to declare.

Download Full-text

Response to induction or hypomethylating agent therapy among patients with myeloproliferative neoplasms progressing to accelerated or leukemic phase.

Journal of Clinical Oncology ◽

10.1200/jco.2017.35.15_suppl.e18561 ◽

2017 ◽

Vol 35 (15_suppl) ◽

pp. e18561-e18561

Author(s):

Gabriela Hobbs ◽

Jennifer Lombardi Story ◽

Maura A. Blaney ◽

Philip C. Amrein ◽

Amir Tahmasb Fathi ◽

...

Keyword(s):

Median Survival ◽

Myeloproliferative Neoplasms ◽

Myeloproliferative Neoplasm ◽

Jak2 V617f ◽

Primary Myelofibrosis ◽

Allogeneic Transplantation ◽

Rank Test ◽

Molecular Testing ◽

Dismal Prognosis ◽

Poor Outcomes

e18561 Background: Post-myeloproliferative neoplasm (MPN) acute myeloid leukemia (AML) and accelerated phase disease (AP) are associated with poor outcomes; the optimal management of these patients at transformation is uncertain in the era of widely available molecular testing. Methods: We performed a retrospective analysis of adult patients with MPN that had transformed into AML (greater than 20% blasts) or AP (10-19% blasts and dysplastic features) from 2006-2016. Patients were 18 or older at AML/AP diagnosis. Outcomes were described by Kaplan and Meier and the Log rank test. Results: We identified 30 patients, with transformed MPN into AML (n = 23) or AP (n = 7), including one patient in AP at presentation. Most were male (73%). Disease evolved from polycythemia vera (n = 6), essential thrombocythemia (n = 11), primary myelofibrosis (n = 9) and other MPN diagnoses (MPN/MDS overlap, n = 3; MPN NOS, n = 1). The median age at MPN diagnosis was 67.5 yrs, and at transformation 72 yrs. The median time from MPN diagnosis to transformation was 5.6 yrs (range 0.3-36.0). 12 patients had JAK2 V617F testing both at MPN diagnosis and AML diagnosis; 6 had JAK2 mutations at both time points and 2 lost JAK2 at transformation. At AML/AP transformation, 11 patients had NGS mutation testing; the most common somatic mutations were NRAS (5/11), RUNX1 (2/11), and SRSF2 (2/11). 20 patients received treatment outside of supportive care. Of these, 8 achieved a CR or CRi (40%; 7/10 with induction and 1/8 with HMA). The only HMA response was on a trial of HMA+SGN33a. The median survival from AML/AP transformation was 5.8 mo. Of treated patients, median survival was 7.4 mo; 37% of treated patients were alive at 1 yr. Nine patients (31%; 7 with AML and 2 with AP) underwent allogeneic transplantation; 2 relapsed during follow-up. 74% of patients treated with allo-HCT were alive at 1 yr after AML/AP transformation. Conclusions: AML or accelerated phase disease arising out of MPN carries a dismal prognosis. HMA monotherapy had little efficacy in this group (0/7 achieved remission). Allogeneic transplantation offered the best chance of survival at one year, but fewer than a third of patients were able to proceed to transplant.

Download Full-text

Combination approach to diagnosis and treatment of an elderly patient with chronic Ph-negative myeloproliferative neoplasm and concomitant surgical pathology. Clinical observation

MD-Onco ◽

10.17650/2782-3202-2021-1-1-61-65 ◽

2021 ◽

Vol 1 (1) ◽

pp. 61-65

Author(s):

Yu. E. Ryabukhina ◽

P. A. Zeynalova ◽

O. I. Timofeeva ◽

F. M. Abbasbeyli ◽

T. V. Ponomarev ◽

...

Keyword(s):

Elderly Patient ◽

Essential Thrombocythemia ◽

Early Stage ◽

Myeloproliferative Neoplasms ◽

Myeloproliferative Neoplasm ◽

Jak2 V617f ◽

Primary Myelofibrosis ◽

Left Femur ◽

Hematopoietic Stem ◽

Chronic Myeloproliferative Neoplasms

Chronic myeloproliferative neoplasms (CMPN), Ph-negative, are of clonal nature, develop on the level of hematopoietic stem cell and are characterized by proliferation of one or more hematopoietic pathways. Currently, the group of Ph-negative CMPN includes essential thrombocythemia, primary myelofibrosis, polycythemia vera, myeloproliferative neoplasm unclassifiable.Identification of mutations in the Jak2 (V617F), CALR, and MPL genes extended understanding of biological features of Ph-negative CMPN and improved differential diagnosis of myeloid neoplasms. Nonetheless, clinical practice still encounters difficulties in clear separation between such disorders as primary myelofibrosis, early-stage and transformation of essential thrombocythemia into myelofibrosis with high thrombocytosis. Thrombocytosis is one of the main risk factors for thromboembolic complications, especially in elderly people.A clinical case of an elderly patient with fracture of the left femur developed in the context of Ph-negative CMPN (myelofibrosis) with high level of thrombocytosis is presented which in combination with enforced long-term immobilization and presence of additional risk created danger of thrombosis and hemorrhage during surgery and in the postoperative period.

Download Full-text

46/1 Haplotype Permits to Follow JAK2 Homologous Recombination: Modeling JAK2V617F clonal Architecture in PV Patients

Blood ◽

10.1182/blood.v120.21.1757.1757 ◽

2012 ◽

Vol 120 (21) ◽

pp. 1757-1757

Author(s):

Salma Hasan ◽

Jean Pierre Le Couedic ◽

Fabrizia Favale ◽

Barbara Monte-Mor ◽

Catherine Lacout ◽

...

Keyword(s):

Homologous Recombination ◽

Conflicts Of Interest ◽

Myeloproliferative Neoplasms ◽

Primary Myelofibrosis ◽

Clonal Structure ◽

Hematopoietic Stem ◽

Clonal Architecture ◽

Specific Pcr ◽

Allele Specific ◽

Proliferative Advantage

Abstract Abstract 1757 Myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell (HSC) disorders characterized by excess proliferation of one or several myeloid lineages. More than 95% polycythemia vera (PV) and 50–60% essential thrombocythemia (ET) and primary myelofibrosis (PMF) patients harbor a somatic 1849 G>T mutation in JAK2 gene. Moreover about 30% of PV patients are homozygous for this mutation due to a loss of heterozygosity after a mitotic homologous recombination (HR). Among 92 haplotypes of chromosome 9p, 46/1 haplotype is strongly associated with the cis-aquisition of JAK2V617F mutation. The purpose of this study was to estimate the clonal frequency of WT, JAK2V617F/+ and JAK2V617F/V617F in progenitors compartments. Here, we have modeled the JAK2V617F clonal architecture in 9 PV patients heterozygous for the 46/1 haplotype by using the level of JAK2 and the 46/1 haplotype as a marker to follow HR. First we measured the global JAK2V617F and 46/1 allele burden in CD34+ cells either by allele-specific PCR or by Ion Torrent sequencing in order to calculate the expected WT, JAK2V617F/+ and JAK2V617F/V617F clones. Next, we compared the results with the experimental clonal frequency of WT, JAK2V617F/+ and JAK2V617F/V617F cells in individual colonies derived from the CD34+CD38+ compartment. In majority of patients, the observed values corresponded to the expected values suggesting that JAK2 46/1 haplotype can be used to estimate JAK2V617F clonal structure in PV patients. In three JAK2 46/1 heterozygous hemochromatosis patients used as controls, no JAK2 46/1 homozygous clone was observed showing that 46/1 haplotype itself was not responsible for HR. Furthermore, we have studied the proliferative advantage of the mutated clones in patients. No proliferative advantage of JAK2V617F clone has been observed in between CD34+CD38− and CD34+CD38+ progenitors stages whereas strong amplification of JAK2V617F clone was found in terminally differentiated polynuclear neutrophils (PNN). Moreover, during evolution of MPN in one patient, we observed an amplification of the JAK2V617F/V617F clone in both the CD34+CD38− and CD34+CD38+cell compartments suggesting acquisition of a proliferative advantage of the homozygous clone over time. This simple modeling could help to understand the effect of treatments on the JAK2V617F clonal structure without working at the unicellular level. Disclosures: No relevant conflicts of interest to declare.

Download Full-text

Macrophage frequency in the bone marrow correlates with morphologic subtype of myeloproliferative neoplasm

Annals of Hematology ◽

10.1007/s00277-020-04304-y ◽

2020 ◽

Vol 100 (1) ◽

pp. 97-104

Author(s):

David C. A. Molitor ◽

Peter Boor ◽

Andreas Buness ◽

Rebekka K. Schneider ◽

Lino L. Teichmann ◽

...

Keyword(s):

Bone Marrow ◽

Stromal Cells ◽

Myeloid Leukemia ◽

Clinical Course ◽

Myeloproliferative Neoplasms ◽

Philadelphia Chromosome ◽

Myeloproliferative Neoplasm ◽

Primary Myelofibrosis ◽

Neoplastic Processes ◽

And Control

AbstractBone marrow (BM) fibrosis in myeloproliferative neoplasms (MPNs) is associated with a poor prognosis. The development of myelofibrosis and differentiation of mesenchymal stromal cells to profibrotic myofibroblasts depends on macrophages. Here, we compared macrophage frequencies in BM biopsies of MPN patients and controls (patients with non-neoplastic processes), including primary myelofibrosis (PMF, n = 18), essential thrombocythemia (ET, n = 14), polycythemia vera (PV, n = 12), and Philadelphia chromosome–positive chronic myeloid leukemia (CML, n = 9). In PMF, CD68-positive macrophages were greatly increased compared to CML (p = 0.017) and control BM (p < 0.001). Similar findings were observed by CD163 staining (PMF vs. CML: p = 0.017; PMF vs. control: p < 0.001). Moreover, CD68-positive macrophages were increased in PV compared with ET (p = 0.009) and reactive cases (p < 0.001). PMF had higher frequencies of macrophages than PV (CD68: p < 0.001; CD163: p < 0.001) and ET (CD68: p < 0.001; CD163: p < 0.001). CD163 and CD68 were often co-expressed in macrophages with stellate morphology in Philadelphia chromosome–negative MPN, resulting in a sponge-like reticular network that may be a key regulator of unbalanced hematopoiesis in the BM space and may explain differences in cellularity and clinical course.

Download Full-text

Bone marrow megakaryocytic activation predicts fibrotic evolution of Philadelphia-negative myeloproliferative neoplasms.

Haematologica ◽

10.3324/haematol.2020.264143 ◽

2020 ◽

pp. 0-0

Author(s):

Mattia Schino ◽

Vincenzo Fiorentino ◽

Elena Rossi ◽

Silvia Betti ◽

Monica Di Cecca ◽

...

Keyword(s):

Bone Marrow ◽

Myeloproliferative Neoplasms ◽

Rapid Evolution ◽

Progression Free Survival ◽

Jak2 V617f ◽

Primary Myelofibrosis ◽

Serum Levels ◽

Chronic Myeloproliferative Neoplasms ◽

Calr Mutations ◽

Wbc Count

Philadelphia-negative chronic myeloproliferative neoplasms (MPNs) have been traditionally considered as indistinctly slowly progressing conditions; recent evidence proves that a subset of cases have a rapid evolution, so that MPNs’ prognosis needs to be personalized. We identified a new morphological parameter, defined as Megakaryocytic Activation (M-ACT) based on the coexistence of megakaryocytic emperipolesis, megakaryocytes (MK) clusters formation and evidence of arrangement of collagen fibers around the perimeter of MK. We retrospectively analyzed the bone marrow biopsy of two MPNs cohorts of patients with polycythemia (PV) (n=64) and non-PV patients [including essential thrombocythemia (ET), and early/prefibrotic primary myelofibrosis (PMF)] (n=222). M-ACT showed a significant correlation with splenomegaly, white blood cell (WBC) count, and LDH serum levels in both groups, with JAK2 V617F allele burden in PV patients, and with CALR mutations, and platelet count in non-PV patients. Progression-free survival, defined as PV-to-secondary MF progression and non-PV-to-overt PMF, was worse in both PV and early/prefibrotic PMF patients with M-ACT in comparison to those without M-ACT (P<.0001). Interestingly, M-ACT was not found in the subgroup of ET patients. In conclusion, M-ACT can be helpful in the differential diagnosis of MPNs and can represent a new morphologic parameter with a predictive value for progression of MPNs.

Download Full-text