Conventional cytogenetics in myelofibrosis: literature review and discussion

Molecular Genetic Profile of Myelofibrosis: Implications in the Diagnosis, Prognosis, and Treatment Advancements

Myelofibrosis (MF) is an essential element of primary myelofibrosis, whereas secondary MF may develop in the advanced stages of other myeloid neoplasms, especially polycythemia vera and essential thrombocythemia. Over the last two decades, advances in molecular diagnostic techniques, particularly the integration of next-generation sequencing in clinical laboratories, have revolutionized the diagnosis, classification, and clinical decision making of myelofibrosis. Driver mutations involving JAK2, CALR, and MPL induce hyperactivity in the JAK-STAT signaling pathway, which plays a central role in cell survival and proliferation. Approximately 80% of myelofibrosis cases harbor additional mutations, frequently in the genes responsible for epigenetic regulation and RNA splicing. Detecting these mutations is crucial for diagnosing myeloproliferative neoplasms (MPNs), especially in cases where no mutations are present in the three driver genes (triple-negative MPNs). While fibrosis in the bone marrow results from the disturbance of inflammatory cytokines, it is fundamentally associated with mutation-driven hematopoiesis. The mutation profile and order of acquiring diverse mutations influence the MPN phenotype. Mutation profiling reveals clonal diversity in MF, offering insights into the clonal evolution of neoplastic progression. Prognostic prediction plays a pivotal role in guiding the treatment of myelofibrosis. Mutation profiles and cytogenetic abnormalities have been integrated into advanced prognostic scoring systems and personalized risk stratification for MF. Presently, JAK inhibitors are part of the standard of care for MF, with newer generations developed for enhanced efficacy and reduced adverse effects. However, only a minority of patients have achieved a significant molecular-level response. Clinical trials exploring innovative approaches, such as combining hypomethylation agents that target epigenetic regulators, drugs proven effective in myelodysplastic syndrome, or immune and inflammatory modulators with JAK inhibitors, have demonstrated promising results. These combinations may be more effective in patients with high-risk mutations and complex mutation profiles. Expanding mutation profiling studies with more sensitive and specific molecular methods, as well as sequencing a broader spectrum of genes in clinical patients, may reveal molecular mechanisms in cases currently lacking detectable driver mutations, provide a better understanding of the association between genetic alterations and clinical phenotypes, and offer valuable information to advance personalized treatment protocols to improve long-term survival and eradicate mutant clones with the hope of curing MF.

Martin A, Wang Y, He M, Spellman SR, Wang T, Deeg HJ, Gupta V, Lee SJ, Bolon YT, Chanock SJ, Machiela MJ, Saber W, Gadalla SM. JAK2 V617F mutation and associated chromosomal alterations in primary and secondary myelofibrosis and post-HCT outcomes

JAK2 V617F is the most common driver mutation in primary or secondary myelofibrosis for which allogeneic hematopoietic cell transplantation (HCT) is the only curative treatment. Knowledge of the prognostic utility of JAK2 alterations in the HCT setting is limited. We identified all patients with MF who received HCT between 2000 and 2016 and had a pre-HCT blood sample (N = 973) available at the Center of International Blood and Marrow Transplant Research biorepository. PacBio sequencing and single nucleotide polymorphism-array genotyping were used to identify JAK2V617F mutation and associated mosaic chromosomal alterations (mCAs), respectively. Cox proportional hazard models were used for HCT outcome analyses. Genomic testing was complete for 924 patients with MF (634 primary MF [PMF], 135 postpolycythemia vera [PPV-MF], and 155 postessential thrombocytopenia [PET-MF]). JAK2V617F affected 562 patients (57.6% of PMF, 97% of PPV-MF, and 42.6% of PET-MF). Almost all patients with mCAs involving the JAK2 region (97.9%) were JAK2V617-positive. In PMF, JAK2V617F mutation status, allele burden, or identified mCAs were not associated with disease progression/relapse, nonrelapse mortality (NRM), or overall survival. Almost all PPV-MF were JAK2V617F-positive (97%), with no association between HCT outcomes and mutation allele burden or mCAs. In PET-MF, JAK2V617F high mutation allele burden (≥60%) was associated with excess risk of NRM, restricted to transplants received in the era of JAK inhibitors (2013-2016; hazard ratio = 7.65; 95% confidence interval = 2.10-27.82; P = .002). However, allele burden was not associated with post-HCT disease progression/relapse or survival. Our findings support the concept that HCT can mitigate the known negative effect of JAK2V617F in patients with MF, particularly for PMF and PPV-MF.

Advances in molecular evaluation of myeloproliferative neoplasms

Myeloproliferative neoplasms (MPN) are a group of clonal hematopoietic stem cell disorders with uncontrolled proliferation of one or more hematopoietic cell types, including myeloid, erythroid and megakaryocytic lineages, and minimal defect in maturation. Most MPN are associated with well-defined molecular abnormalities involving genes that encode protein tyrosine kinases that lead to constitutive activation of the downstream signal transduction pathways and confer cells proliferative and survival advantage. Genome-wide sequencing analyses have discovered secondary cooperating mutations that are shared by most of the MPN subtypes as well as other myeloid neoplasms and play a major role in disease progression. Without appropriate management, the natural history of most MPN consists of an initial chronic phase and a terminal blast phase. Molecular aberrations involving protein tyrosine kinases have been used for the diagnosis, classification, detection of minimal/measurable residual disease, and target therapy. We review recent advances in molecular genetic aberrations in MPN with a focus on MPN associated with gene rearrangements or mutations involving tyrosine kinase pathways.

Myelofibrosis and Survival Prognostic Models: A Journey between Past and Future

Among the myeloproliferative diseases, myelofibrosis is a widely heterogeneous entity characterized by a highly variable prognosis. In this context, several prognostic models have been proposed to categorize these patients appropriately. Identifying who deserves more invasive treatments, such as bone marrow transplantation, is a critical clinical need. Age, complete blood count (above all, hemoglobin value), constitutional symptoms, driver mutations, and blast cells have always represented the milestones of the leading models still used worldwide (IPSS, DIPSS, MYSEC-PM). Recently, the advent of new diagnostic techniques (among all, next-generation sequencing) and the extensive use of JAK inhibitor drugs have allowed the development and validation of new models (MIPSS-70 and version 2.0, GIPSS, RR6), which are continuously updated. Finally, the new frontier of artificial intelligence promises to build models capable of drawing an overall survival perspective for each patient. This review aims to collect and summarize the existing standard prognostic models in myelofibrosis and examine the setting where each of these finds its best application.

Essential Thrombocythemia and Post-Essential Thrombocythemia Myelofibrosis: Updates on Diagnosis, Clinical Aspects, and Management

Although several decades have passed since the description of myeloproliferative neoplasms (MPN), many aspects of their pathophysiology have not been elucidated. In this review, we discuss the mutational landscape of patients with essential thrombocythemia (ET), prognostic scores and salient pathology, and clinical points. We discuss also the diagnostic challenges of differentiating ET from prefibrotic MF. We then focus on post-essential thrombocythemia myelofibrosis (post-ET MF), a rare subset of MPN that is usually studied in conjunction with post-polycythemia vera MF. The transition of ET to post-ET MF is not well studied on a molecular level, and we present available data. Patients with secondary MF could benefit from allogenic hematopoietic stem cell transplantation, and we present available data focusing on post-ET MF.

Transcriptional configurations of myeloproliferative neoplasms

Myeloproliferative neoplasms (MPNs) is an umbrella term for several heterogenous diseases, which are characterized by their stem cell origin, clonal hematopoiesis and increase of blood cells of the myeloid lineage. The focus will be on BCR-ABL1 negative MPNs, polycythemia vera (PV), primary myelofibrosis (PMF), essential thrombocythemia (ET). Seminal findings in the field of MPN were driven by genomic analysis, focusing on dissecting genomic changes MPN patients. This led to identification of major MPN driver genes, JAK2, MPL and CALR. Transcriptomic analysis promises to bridge the gap between genetic and phenotypic characterization of each patient's tumor and with the advent of single cell sequencing even for each MPN cancer cell. This review will focus on efforts to mine the bulk transcriptome of MPN patients, including analysis of fusion genes and splicing alterations which can be addressed with RNA-seq technologies. Furthermore, this paper aims to review recent endeavors to elucidate tumor heterogeneity in MPN hematopoietic stem and progenitor cells using single cell technologies. Finally, it will highlight current shortcoming and future applications to advance the field in MPN biology and improve patient diagnostics using RNA-based assays.

The Prognostic Role of Cytogenetics Analysis in Philadelphia Negative Myeloproliferative Neoplasms

Myeloproliferative neoplasms (MPNs) are clonal stem cell disorders characterized collectively by clonal proliferation of myeloid cells with variable morphologic maturity and hematopoietic efficiency. Although the natural history of these neoplasms can be measured sometimes in decades more than years, the cytogenetics analysis can offer useful information regarding the prognosis. Cytogenetics has a well-established prognostic role in acute leukemias and in myelodysplastic syndromes, where it drives the clinical decisions. NGS techniques can find adverse mutations with clear prognostic value and are currently included in the prognostic evaluation of MPNs in scores such as MIPSS, GIPSS, MIPSS-PV, and MIPSS-ET. We suggest that cytogenetics (considering its availability and relative cost) has a role regarding prognostic and therapeutic decisions.

Effect of pre-transplant JAK1/2 inhibitors and CD34 dose on transplant outcomes in myelofibrosis

Allogeneic hematopoeitic cell transplantation (allo-HCT) is the only curative treatment for myelofibrosis (MF). We evaluate the impact of various factors on survival outcomes post-transplant in MF. Data of 89 consecutive MF patients (primary 47%) who underwent allo-HCT between 2005 and 2018 was evaluated. Fifty-four percent patients had received JAK1/2 inhibitors (JAKi) pre-HCT. The median CD34 count was 7.1x10⁶ cells/kg. Graft failure was seen in 10% of the patients. Grade 3-4 acute GVHD (aGVHD) and moderate/severe chronic graft versus host disease (cGVHD) occurred in 24% and 40% patients, respectively. Two-year overall survival (OS) and relapse free survival (RFS) were 51% and 43%, respectively. Cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) at 2 years were 11% and 46%, respectively. Higher CD34 cell dose (≤5 × 10⁶ cells/kg vs 5-9 or ≥9 × 10⁶  cells/kg) and lower pre-HCT ferritin (</=1000 ng/ml) were associated with better OS, RFS and lower NRM. Grade 3-4 aGVHD was associated with higher NRM. Use of pre-transplant JAKi was associated with lower incidence of grade 3-4 aGVHD. In summary, higher CD34 cell dose is associated with better allo-HCT outcomes in MF and pre-HCT JAKi use is associated with reduced risk of severe aGVHD. These two modifiable parameters should be considered during allo-HCT for MF.

A provider's guide to primary myelofibrosis: pathophysiology, diagnosis, and management

Although understanding of the pathogenesis and molecular biology of primary myelofibrosis continues to improve, treatment options are limited, and several biological features remain unexplained. With an appropriate clinical history, exam, laboratory evaluation, and bone marrow biopsy, the diagnosis can often be established. Recent studies have better characterized prognostic factors and driver mutations in myelofibrosis, facilitated by use of next-generation sequencing. These advances have facilitated development of a management strategy that is based on both risk factors and clinical phenotype. For low-risk patients, treatment will depend on symptom severity. For patients with higher-risk disease, several treatments are available including JAK inhibitors, allogeneic hematopoietic stem cell transplant, and clinical trials using novel molecularly targeted therapies and rational drug combinations. In this review, we outline what is known about the disease pathogenesis, discuss an approach to reaching the diagnosis, review the prognosis of myelofibrosis, and detail current therapeutic strategies.

A distinct molecular mutational profile and its clinical impact in essential thrombocythemia and primary myelofibrosis patients

BACKGROUND

Classical MPNs including ET and PMF have a chronic course and potential for leukaemic transformation. Timely diagnosis is obligatory to ensure appropriate management and positive outcomes. The aim of this study was to determine the mutational profile, clinical characteristics and outcome of ET and PMF patients in Pakistani population.

METHODS

This was a prospective observational study conducted between 2012 and 2017 at NIBD. Patients were diagnosed and risk stratified according to international recommendations. Response to treatment was assessed by IWG criteria.

RESULTS

Of the total 137 patients analysed, 75 were ET and 62 were PMF. JAK2 positivity was seen in 51 cases (37.2%), CALR in 41 cases (29.9%), while triple-negative in 17 (12.4%) cases. None of the patients in the present study were MPL positive. Overall survival for patients with ET and PMF was 92.5 and 86.0% respectively and leukaemia free survival was 100 and 91.6% respectively, at a median follow-up of 12 months. Leukaemic transformation occurred in 6.5% of MF patients; among them, JAK2 mutation was frequently found. Molecular mutations did not influence the OS in ET whereas in PMF, OS was shortest in the triple-negative PMF group as compared to the JAK2 and CALR positive patient groups.

CONCLUSION

This study shows a different spectrum of molecular mutations in ET and PMF patients in Pakistani population as compared to other Asian countries. Similarly, the risk of leukaemic transformation in ET and PMF is relatively lower in our population of patients. The factors responsible for these phenotypic and genotypic differences need to be analysed in large scale studies with longer follow-up of patients.

Hippo kinase loss contributes to del(20q) hematologic malignancies through chronic innate immune activation

Heterozygous deletions within chromosome 20q, or del(20q), are frequent cytogenetic abnormalities detected in hematologic malignancies. To date, identification of genes in the del(20q) common deleted region that contribute to disease development have remained elusive. Through assessment of patient gene expression, we have identified STK4 (encoding Hippo kinase MST1) as a 20q gene that is downregulated below haploinsufficient amounts in myelodysplastic syndrome (MDS) and myeloproliferative neoplasm (MPN). Hematopoietic-specific gene inactivation in mice revealed Hippo kinase loss to induce splenomegaly, thrombocytopenia, megakaryocytic dysplasia, and a propensity for chronic granulocytosis; phenotypes that closely resemble those observed in patients harboring del(20q). In a JAK2-V617F model, heterozygous Hippo kinase inactivation led to accelerated development of lethal myelofibrosis, recapitulating adverse MPN disease progression and revealing a novel genetic interaction between these 2 molecular events. Quantitative serum protein profiling showed that myelofibrotic transformation in mice was associated with cooperative effects of JAK2-V617F and Hippo kinase inactivation on innate immune-associated proinflammatory cytokine production, including IL-1β and IL-6. Mechanistically, MST1 interacted with IRAK1, and shRNA-mediated knockdown was sufficient to increase IRAK1-dependent innate immune activation of NF-κB in human myeloid cells. Consistent with this, treatment with a small molecule IRAK1/4 inhibitor rescued the aberrantly elevated IL-1β production in the JAK2-V617F MPN model. This study identified Hippo kinase MST1 (STK4) as having a central role in the biology of del(20q)-associated hematologic malignancies and revealed a novel molecular basis of adverse MPN progression that may be therapeutically exploitable via IRAK1 inhibition.

Altered NFE2 activity predisposes to leukemic transformation and myelosarcoma with AML-specific aberrations

In acute myeloid leukemia (AML), acquired genetic aberrations carry prognostic implications and guide therapeutic decisions. Clinical algorithms have been improved by the incorporation of novel aberrations. Here, we report the presence and functional characterization of mutations in the transcription factor NFE2 in patients with AML and in a patient with myelosarcoma. We previously described NFE2 mutations in patients with myeloproliferative neoplasms and demonstrated that expression of mutant NFE2 in mice causes a myeloproliferative phenotype. Now, we show that, during follow-up, 34% of these mice transform to leukemia presenting with or without concomitant myelosarcomas, or develop isolated myelosarcomas. These myelosarcomas and leukemias acquired AML-specific alterations, including the murine equivalent of trisomy 8, loss of the AML commonly deleted region on chromosome 5q, and mutations in the tumor suppressor Trp53 Our data show that mutations in NFE2 predispose to the acquisition of secondary changes promoting the development of myelosarcoma and/or AML.

Assessing copy number aberrations and copy neutral loss of heterozygosity across the genome as best practice: An evidence based review of clinical utility from the cancer genomics consortium (CGC) working group for myelodysplastic syndrome, myelodysplastic/myeloproliferative and myeloproliferative neoplasms

Multiple studies have demonstrated the utility of chromosomal microarray (CMA) testing to identify clinically significant copy number alterations (CNAs) and copy-neutral loss-of-heterozygosity (CN-LOH) in myeloid malignancies. However, guidelines for integrating CMA as a standard practice for diagnostic evaluation, assessment of prognosis and predicting treatment response are still lacking. CMA has not been recommended for clinical work-up of myeloid malignancies by the WHO 2016 or the NCCN 2017 guidelines but is a suggested test by the European LeukaemiaNet 2013 for the diagnosis of primary myelodysplastic syndrome (MDS). The Cancer Genomics Consortium (CGC) Working Group for Myeloid Neoplasms systematically reviewed peer-reviewed literature to determine the power of CMA in (1) improving diagnostic yield, (2) refining risk stratification, and (3) providing additional genomic information to guide therapy. In this manuscript, we summarize the evidence base for the clinical utility of array testing in the workup of MDS, myelodysplastic/myeloproliferative neoplasms (MDS/MPN) and myeloproliferative neoplasms (MPN). This review provides a list of recurrent CNAs and CN-LOH noted in this disease spectrum and describes the clinical significance of the aberrations and how they complement gene mutation findings by sequencing. Furthermore, for new or suspected diagnosis of MDS or MPN, we present suggestions for integrating genomic testing methods (CMA and mutation testing by next generation sequencing) into the current standard-of-care clinical laboratory testing (karyotype, FISH, morphology, and flow).

Molecular Markers and Prognosis of Myelofibrosis in the Genomic Era: A Meta-analysis

Molecular markers are important in guiding treatment and predicting outcome in the genomic era. Meta-analysis of molecular markers in myelofibrosis through a search of PubMed and Medline through October 31, 2017 was performed. Markers with more than 3 studies that compared overall survival (OS) and leukemia-free survival (LFS) were analyzed. A total of 16 studies were included. Hazard ratios (HRs) for OS were as follows: IDH 2.65 (95% confidence interval [CI], 1.66-4.21), SRSF2 2.12 (95% CI, 1.18-3.79), high-risk myeloma 2.11 (95% CI, 1.70-2.61), ASXL1 1.92 (95% CI, 1.60-2.32), EZH2 1.88 (95% CI, 1.32-2.67), JAK2 1.41 (95% CI, 1.04-1.93) in the univariate analysis and 1.49 (95% CI, 0.42-5.30) in the multivariate analysis. LFS of JAK2 and SRSF2 had HRs of 1.81 (95% CI, 0.42-5.30) and 0.36 (95% CI, 0.02-6.48), respectively. In conclusion, mutations in IDH, SRSF2, and ASXL1 had worse prognosis in OS with HRs around 2. JAK2 and SRSF2 mutation were not associated with increased leukemia transformation. The adverse effect of triple-negative, which was often compared with CALR mutation, needs to be explored.

High Frequency of Copy-Neutral Loss of Heterozygosity in Patients with Myelofibrosis

Myelofibrosis is the rarest and most severe type of Philadelphia-negative classical myeloproliferative neoplasms. Although mutually exclusive driver mutations in JAK2, MPL, or CALR that activate JAK-STAT pathway have been related to the pathogenesis of the disease, chromosome abnormalities have also been associated with the phenotype and prognosis of the disease. Here, we report the use of a chromosomal microarray platform consisting of both oligo and SNP probes to improve the detection of chromosome abnormalities in patients with myelofibrosis. Sixteen patients with myelofibrosis were tested, and the results were compared to karyotype analysis. Driver mutations in JAK2, MPL, or CALR were investigated by PCR and MLPA. Conventional cytogenetics revealed chromosome abnormalities in 3 out of 16 cases (18.7%), while chromosomal microarray analysis detected copy-number variations (CNV) or copy-neutral loss of heterozygosity (CN-LOH) alterations in 11 out of 16 (68.7%) patients. These included 43 CN-LOH, 14 deletions, 1 trisomy, and 1 duplication. Ten patients showed multiple chromosomal abnormalities, varying from 2 to 13 CNVs or CN-LOHs. Mutational status for JAK2, CALR, and MPL by MLPA revealed a total of 3/16 (18.7%) patients positive for the JAK2 V617F mutation, 9 with CALR deletion or insertion and 1 positive for MPL mutation. Considering that most of the CNVs identified were smaller than the karyotype resolution and the high frequency of CN-LOHs in our study, we propose that chromosomal microarray platforms that combine oligos and SNP should be used as a first-tier genetic test in patients with myelofibrosis.

3q26.2/EVI1 rearrangement is associated with poor prognosis in classical Philadelphia chromosome-negative myeloproliferative neoplasms

Classical Philadelphia chromosome-negative myeloproliferative neoplasms are a group of closely related myeloid disorders with different histologic features and clinical presentations at an early stage, but all later develop into a similar fibrotic stage with variable risk of acute transformation. The significance of 3q26.2/EVI1 rearrangement has been well recognized in acute myeloid leukemia, myelodysplastic syndrome, and chronic myeloid leukemia. However, the clinical importance of 3q26.2/EVI1 rearrangement in classical Philadelphia chromosome-negative myeloproliferative neoplasms is unknown. Here we reported 15 patients with classical Philadelphia chromosome-negative myeloproliferative neoplasms showing 3q26.2 rearrangement, including inv(3)(q21q26.2) (n=6), t(3;21)(q26.2;q22)(n=4), t(3;3)(q21;q26.2)(n=3), inv(3)(q13.3q26.2)(n=1), and t(3;12)(q26.2;p13)(n=1). In addition to 3q26.2 rearrangement, 9 of 15 cases had other concurrent karyotypical abnormalities, including -7/7q- and -5/5q-. There were 8 men and 7 women with a median age of 59 years (range, 35-79 years) at initial diagnosis of myeloproliferative neoplasms: 8 patients had primary myelofibrosis, 4 had polycythemia vera, and 3 had essential thrombocythemia. JAK2 V617F mutation was detected in 8/14 patients, including 4/4 with polycythemia vera. The median interval from the initial diagnosis of myeloproliferative neoplasms to the detection of 3q26.2 rearrangement was 44 months (range, 1-219 months). At time of emergence of 3q26.2 rearrangement, 11 patients were in blast phase and 2 patients had increased blasts (6-19%). Dyspoiesis, predominantly in megakaryocytes, were detected in all patients with adequate specimens at time of 3q26.2 rearrangement. Following 3q26.2 rearrangement, 12 patients received chemotherapy, but none of them achieved complete remission. Of 14 patients with follow-up information, all died with a median overall survival time of only 3 months (range 0-14 months) after the emergence of 3q26.2 rearrangement. In summary, 3q26.2 rearrangement in classical Philadelphia chromosome-negative myeloproliferative neoplasms is associated with other concurrent cytogenetic abnormalities, a rapid disease progression and blast transformation, a poor response to chemotherapy and a dismal prognosis.

A Rare Case of Primary Myelofibrosis in a 14-Year-Old Patient With Congenital Asplenia

Primary myelofibrosis (PMF) is rarely diagnosed in children, and in most cases in children younger than 3 years old. Pediatric PMF generally follows a benign course and is usually managed supportively with blood transfusions and prophylactic antibiotics for infections. We present a case of a 17-year-old girl diagnosed with PMF at the age of 14 years. A computed tomography scan performed at the time of an appendectomy showed congenital asplenism. To our knowledge, this is only the third case of myelofibrosis and congenital asplenism to be reported in the literature. Whether asplenism contributed to the development of myelofibrosis is not known.

Primary myelofibrosis: 2017 update on diagnosis, risk-stratification, and management

Disease overview: Primary myelofibrosis (PMF) is a myeloproliferative neoplasm (MPN) characterized by stem cell-derived clonal myeloproliferation that is often but not always accompanied by JAK2, CALR or MPL mutation, abnormal cytokine expression, bone marrow fibrosis, anemia, splenomegaly, extramedullary hematopoiesis (EMH), constitutional symptoms, cachexia, leukemic progression and shortened survival.

DIAGNOSIS

Diagnosis is based on bone marrow morphology. The presence of JAK2, CALR or MPL mutation is supportive but not essential for diagnosis; approximately 90% of patients carry one of these mutations and 10% are "triple-negative." None of these mutations are specific to PMF and are also seen in essential thrombocythemia (ET). According to the revised 2016 World Health Organization (WHO) classification and diagnostic criteria, "prefibrotic" PMF (pre-PMF) is distinguished from "overtly fibrotic" PMF; the former might mimic ET in its presentation and it is prognostically relevant to distinguish the two. Risk stratification: The Dynamic International Prognostic Scoring System-plus (DIPSS-plus) uses eight predictors of inferior survival: age >65 years, hemoglobin <10 g/dL, leukocytes >25 × 10⁹ /L, circulating blasts ≥1%, constitutional symptoms, red cell transfusion dependency, platelet count <100 × 10⁹ /L and unfavorable karyotype (i.e., complex karyotype or sole or two abnormalities that include +8, -7/7q-, i(17q), inv(3), 5/5q-, 12p-, or 11q23 rearrangement). The presence of 0, 1, "2 or 3" and ≥4 adverse factors defines low, intermediate-1, intermediate-2 and high-risk disease with median survivals of approximately 15.4, 6.5, 2.9 and 1.3 years, respectively. Most recently, DIPSS-plus-independent adverse prognostic relevance has been demonstrated for certain mutations including ASXL1 and SRSF2 whereas patients with type 1/like CALR mutations, compared to their counterparts with other driver mutations, displayed significantly better survival. Risk-adapted therapy: Observation alone is a reasonable treatment strategy for asymptomatic low or intermediate-1 DIPSS-plus risk disease, especially in the absence of high-risk mutations. All other patients with high or intermediate-2 risk disease, or those harboring high-risk mutations such as ASXL1 or SRSF2, should be considered for stem cell transplant, which is currently the only treatment modality with the potential to favorably modify the natural history of the disease. Non-transplant candidates should be encouraged to participate in clinical trials, since the value of conventional drug therapy, including the use of JAK2 inhibitors, is limited to symptoms palliation and reduction in spleen size. Specifically, JAK2 inhibitors have not been shown to induce complete clinical or cytogenetic remissions or significantly affect JAK2/CALR/MPL mutant allele burden. Splenectomy is considered for drug-refractory splenomegaly. Involved field radiotherapy is most useful for post-splenectomy hepatomegaly, non-hepatosplenic EMH, PMF-associated pulmonary hypertension and extremity bone pain. Am. J. Hematol. 91:1262-1271, 2016. © 2016 Wiley Periodicals, Inc.

Clinicopathologic evaluation of cytopenic patients with isolated trisomy 8: a detailed comparison between idiopathic cytopenia of unknown significance and low-grade myelodysplastic syndrome

The significance of an isolated trisomy 8 (+8) in the diagnosis of myelodysplastic syndrome (MDS) is not well established. It is common in MDS, but is not considered as an MDS-defining abnormality in the absence of morphologic dysplasia. We evaluated two groups of patients with isolated +8 and either low-grade MDS (LG-MDS) or idiopathic cytopenia of undetermined significance (ICUS). At presentation, ICUS patients had a lower platelet count (85.0 vs 163.5 × 10⁹ cells/L; p = 0.02), while MDS patients had more frequent incidence of isolated anemia (64% vs 0%, p = 0.007). A subset (36%) of ICUS patients progressed to MDS or AML. These patients presented with more severe neutropenia (0.9 vs 3.1 × 10³/μL, p = 0.01) and a trend toward a higher proportion (>50%) of +8 metaphases compared to those that did not progress (p = 0.05). Thus, ICUS patients with isolated +8 may progress to MDS and AML and deserve close clinical follow-up.

Allogeneic Hematopoietic Stem-Cell Transplantation for Myelofibrosis: A Practical Review

Myelofibrosis is a myeloproliferative neoplasm with cardinal features of extramedullary hematopoiesis, hepatosplenomegaly, cytopenias, and constitutional symptoms that result in shortened survival and leukemic transformation. It is a disease predominantly of the elderly, and currently available therapies only offer symptom control without curative benefit or ability to alter disease progression. Allogeneic hematopoietic stem-cell transplant (HSCT) is the only potentially curative intervention; however, this is only feasible in younger and medically fit patients and selectively offered to those with high-risk disease. Despite ongoing advancements, HSCT is associated with substantial morbidity and mortality, and the determination of which patients with myelofibrosis are ideal candidates and the selection of the opportune moment to proceed with transplantation remains challenging. This review summarizes our current recommendations for the role of and indications for HSCT in myelofibrosis.

A t(11;14)(p13;q11.2) in myelofibrosis following polycythemia vera

Chromosomal abnormalities at 14q11, which encodes the T-cell receptor α and δ chain genes, are generally specific for T-cell malignancies, and are rarely reported in other malignancies. We report a novel t(11;14)(p13;q11.2) in a patient with myelofibrosis (MF) following polycythemia vera (PV). This 55-year-old male developed post-PV MF 12 years after the initial diagnosis of PV. He had a normal karyotype at polycythemic disease stage, t(11;14)(p13;q11.2) was newly detected at the time of fibrotic transformation. Therefore, it is likely that this clonal chromosomal abnormality was associated with progression of disease.

Molecular Pathogenesis and Clinical Significance of Driver Mutations in Primary Myelofibrosis: A Review

Primary myelofibrosis (PMF) is a rare chronic BCR-ABL1-negative myeloproliferative neoplasm characterized by progressive bone marrow fibrosis, inefficient hematopoiesis, and shortened survival. The clinical manifestations of PMF include splenomegaly, consequent to extramedullary hematopoiesis, pancytopenias, and an array of potentially debilitating constitutional symptoms. The diagnosis is based on bone marrow morphology and clinical criteria. Mutations in the JAK2 (V617F), MPL (W515), and CALR (exon 9 indel) genes are found in approximately 90% of patients whereas the remaining 10% are so-called triple negatives. Activation of the JAK/STAT pathway results in overproduction of abnormal megakaryocytes leading to bone marrow fibrosis. These mutations might be accompanied by other mutations, such as ASXL1. The commonly used prognostication scoring for PMF is based on the International Prognostic Scoring System. The subsequently developed Dynamic International Prognostic Scoring System-plus employs clinical as well as cytogenetic variables. In PMF, CALR mutation is associated with superior survival and ASXL1 with inferior outcome. Patients with triple-negative PMF have a higher incidence of leukemic transformation and lower overall survival compared with CALR- or JAK2-mutant patients. The impact of genetic lesions on survival is independent of current prognostic scoring systems. These observations indicate that driver and passenger mutations define distinct disease entities within PMF. Accounting for them is not only relevant to clinical decision-making, but should also be considered in designing clinical trials.

Myeloproliferative neoplasms: Current molecular biology and genetics

Myeloproliferative neoplasms (MPNs) are clonal disorders characterized by increased production of mature blood cells. Philadelphia chromosome-negative MPNs (Ph-MPNs) consist of polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). A number of stem cell derived mutations have been identified in the past 10 years. These findings showed that JAK2V617F, as a diagnostic marker involving JAK2 exon 14 with a high frequency, is the best molecular characterization of Ph-MPNs. Somatic mutations in an endoplasmic reticulum chaperone, named calreticulin (CALR), is the second most common mutation in patients with ET and PMF after JAK2 V617F mutation. Discovery of CALR mutations led to the increased molecular diagnostic of ET and PMF up to 90%. It has been shown that JAK2V617F is not the unique event in disease pathogenesis. Some other genes' location such as TET oncogene family member 2 (TET2), additional sex combs-like 1 (ASXL1), casitas B-lineage lymphoma proto-oncogene (CBL), isocitrate dehydrogenase 1/2 (IDH1/IDH2), IKAROS family zinc finger 1 (IKZF1), DNA methyltransferase 3A (DNMT3A), suppressor of cytokine signaling (SOCS), enhancer of zeste homolog 2 (EZH2), tumor protein p53 (TP53), runt-related transcription factor 1 (RUNX1) and high mobility group AT-hook 2 (HMGA2) have also identified to be involved in MPNs phenotypes. Here, current molecular biology and genetic mechanisms involved in MNPs with a focus on the aforementioned factors is presented.

Myeloproliferative Neoplasms in Children

Myeloproliferative neoplasms (MPN) are a group of clonal hematopoietic stem cell disorders characterized by aberrant proliferation of one or more myeloid lineages often with increased immature cells in the peripheral blood. The three classical BCR-ABL-negative MPNs are: 1) polycythemia vera (PV), 2) essential thrombocythemia (ET), and 3) primary myelofibrosis (PMF), which are typically disorders of older adults and are exceedingly rare in children. The diagnostic criteria for MPNs remain largely defined by clinical, laboratory and histopathology assessments in adults, but they have been applied to the pediatric population. The discovery of the JAK2 V617F mutation, and more recently, MPL and CALR mutations, are major landmarks in the understanding of MPNs. Nevertheless, they rarely occur in children, posing a significant diagnostic challenge given the lack of an objective, clonal marker. Therefore, in pediatric patients, the diagnosis must rely heavily on clinical and laboratory factors, and exclusion of secondary disorders to make an accurate diagnosis of MPN. This review focuses on the clinical presentation, diagnostic work up, differential diagnosis, treatment and prognosis of the classical BCR-ABL-negative MPNs (PV, ET and PMF) in children and highlights key differences to the adult diseases. Particular attention will be given to pediatric PMF, as it is the only disorder of this group that is observed in infants and young children, and in many ways appears to be a unique entity compared to adult PMF.

Del(20q) in patients with chronic lymphocytic leukemia: a therapy-related abnormality involving lymphoid or myeloid cells

Deletion 20q (Del(20q)), a common cytogenetic abnormality in myeloid neoplasms, is rare in chronic lymphocytic leukemia. We report 64 patients with chronic lymphocytic leukemia and del(20q), as the sole abnormality in 40, a stemline abnormality in 21, and a secondary abnormality in 3 cases. Fluorescence in situ hybridization (FISH) analysis revealed an additional high-risk abnormality, del(11q) or del(17p), in 25/64 (39%) cases. In most cases, the leukemic cells showed atypical cytologic features, unmutated IGHV (immunoglobulin heavy-chain variable region) genes, and ZAP70 positivity. The del(20q) was detected only after chemotherapy in all 27 cases with initial karyotypes available. With a median follow-up of 90 months, 30 patients (47%) died, most as a direct consequence of chronic lymphocytic leukemia. Eight patients developed a therapy-related myeloid neoplasm, seven with a complex karyotype. Combined morphologic and FISH analysis for del(20q) performed in 12 cases without morphologic evidence of a myeloid neoplasm localized the del(20q) to the chronic lymphocytic leukemia cells in 5 (42%) cases, and to myeloid/erythroid cells in 7 (58)% cases. The del(20q) was detected in myeloid cells in all 4 cases of myelodysplastic syndrome. In aggregate, these data indicate that chronic lymphocytic leukemia with del(20q) acquired after therapy is heterogeneous. In cases with morphologic evidence of dysplasia, the del(20q) likely resides in the myeloid lineage. However, in cases without morphologic evidence of dysplasia, the del(20q) may represent clonal evolution and disease progression. Combining morphologic analysis with FISH for del(20q) or performing FISH on immunomagnetically selected sub-populations to localize the cell population with this abnormality may help guide patient management.

Janus kinase-1 and Janus kinase-2 inhibitors for treating myelofibrosis

BACKGROUND

Myelofibrosis is a bone marrow disorder characterized by excessive production of reticulin and collagen fiber deposition caused by hematological and non-hematological disorders. The prognosis of myelofibrosis is poor and treatment is mainly palliative. Janus kinase inhibitors are a novel strategy to treat people with myelofibrosis.

OBJECTIVES

To determine the clinical benefits and harms of Janus kinase-1 and Janus kinase-2 inhibitors for treating myelofibrosis secondary to hematological or non-hematological conditions.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, the Cochrane Library 2014, Issue 11), Ovid MEDLINE (from 1946 to 13 November 2014), EMBASE (from 1980 to 12 January 2013), and LILACS (from 1982 to 20 November 2014). We searched WHO International Clinical Trials Registry Platform and The metaRegister of Controlled Trials. We also searched for conference proceedings of the American Society of Hematology (from 2009 to October 2013), European Hematology Association (from 2009 to October 2013), American Society of Clinical Oncology (from 2009 to October 2013), and European Society of Medical Oncology (from 2009 to October 2013). We included searches in FDA, European Medicines Agency, and Epistemonikos. We handsearched the references of all identified included trials, and relevant review articles. We did not apply any language restrictions. Two review authors independently screened search results.

SELECTION CRITERIA

We included randomized clinical trials comparing Janus kinase-1 and Janus kinase-2 inhibitors with placebo or other treatments. Both previously treated and treatment naive patients were included.

DATA COLLECTION AND ANALYSIS

We used the hazard ratio (HR) and 95% confidence interval (95% CI) for overall survival, progression-free survival and leukemia-free survival, risk ratio (RR) and 95% CI for reduction in spleen size and adverse events binary data, and standardized mean differences (SMD) and 95% CI for continuous data (health-related quality of life). Two review authors independently extracted data and assessed the risk of bias of included trials. Primary outcomes were overall survival, progression-free survival and adverse events.

MAIN RESULTS

We included two trials involving 528 participants, comparing ruxolitinib with placebo or best available therapy (BAT). As the two included trials had different comparators we did not pool the data. The confidence in the results estimates of these trials was low due to the bias in their design, and their limited sample sizes that resulted in imprecise results.There is low quality evidence for the effect of ruxolitinib on survival when compared with placebo at 51 weeks of follow-up (HR 0.51, 95% CI 0.27 to 0.98) and compared with BAT at 48 weeks of follow-up (HR 0.70, 95% CI 0.20 to 2.47). Similarly there was very low quality evidence for the effect of ruxolitinib on progression free survival compared with BAT (HR 0.81, 95% CI 0.47 to 1.39).There is low quality evidence for the effect of ruxolitinib in terms of quality of life. Compared with placebo, the drug achieved a greater proportion of patients with a significant reduction of symptom scores (RR 8.82, 95% CI 4.40 to 17.69), and treated patients with ruxolitinib obtained greater MFSAF scores at the end of follow-up (MD -87.90, 95% CI -139.58 to -36.22). An additional trial showed significant differences in EORTC QLQ-C30 scores when compared ruxolitinib with best available therapy (MD 7.60, 95% CI 0.35 to 14.85).The effect of ruxolitinib on reduction in the spleen size of participants compared with placebo or BAT was uncertain (versus placebo: RR 64.58, 95% CI 9.08 to 459.56, low quality evidence; versus BAT: RR 41.78, 95% CI 2.61 to 669.75, low quality evidence).There is low quality evidence for the effect of the drug compared with placebo on anemia (RR 2.35, 95% CI 1.62 to 3.41), neutropenia (RR 3.57, 95% CI 1.02 to 12.55) and thrombocytopenia (RR 9.74, 95% CI 2.32 to 40.96). Ruxolitinib did not result in differences versus BAT in the risk of anemia (RR 1.35, 95% CI 0.91 to 1.99, low quality evidence) or thrombocytopenia (RR 1.20; 95% CI 0.44 to 3.28, low quality evidence). The risk of non-hematologic grade 3 or 4 adverse events (including fatigue, arthralgia, nausea, diarrhea, extremity pain and pyrexia) was similar when ruxolitinib was compared with placebo or BAT. The rate of neutropenia comparing ruxolitinib with standard medical treatment was not reported by the trial.

AUTHORS' CONCLUSIONS

Currently, there is insufficient evidence to allow any conclusions regarding the efficacy and safety of ruxolitinib for treating myelofibrosis. The findings of this Cochrane review should be interpreted with caution as they are based on trials sponsored by industry, and include a small number of patients. Unless powered randomized clinical trials provide strong evidence of a treatment effect, and the trade-off between potential benefits and harms is established, clinicians should be cautious when administering ruxolitinib for treating patients with myelofibrosis.

Cytogenetic studies and their prognostic contribution in 565 Chinese patients with primary myelofibrosis

To study the feature and prognostic contribution of cytogenetic information in Chinese patients with primary myelofibrosis (PMF), we analyzed cytogenetic data from 565 patients with PMF. One hundred and sixty-two subjects (29%) had abnormal karyotypes, including trisomy 8 (45; 28%), deletion of 20q (25; 15%), deletion of 13q (13; 8%), deletion of 11q (12; 7%), and abnormal chromosome 1 (21; 13%); balanced translocations (14; 9%); a complex karyotype (CK; 30; 19%), and a monosomal karyotype (MK; 19; 12%). Using these data, we showed that the Dynamic International Prognostic Scoring System (DIPSS)-plus, which includes cytogenetic information, is a better survival predictor than the DIPSS. We next used our data to construct the following two cytogenetic-based cohorts: (1) favorable karyotype-subjects with a normal karyotype, a CK that is not a MK, +8 only or a balanced translocation only and (2) unfavorable karyotype-all others. The median survival times were not reached and were 52 month (95% CI, 32-72 months; P = 0.01) in patients with favorable and unfavorable karyotypes, respectively. These data provided the detailed cytogenetic information in Chinese patients with PMF and confirmed the impact of cytogenetic abnormalities on survival in Chinese patients.

Paediatric idiopathic myelofibrosis

Pediatric myelofibrosis is a rare disorder. It is usually secondary to other diseases. Rarely, when no underlying cause is found, it is termed idiopathic. We present here, a rare case of idiopathic myelofibrosis in a 10 year old male child. Bone marrow aspirate was dilute. Bone biopsy showed marrow fibrosis, with grade 2-3 reticulin fibres, with no evidence of granuloma, parasite or infilterative disorder. Acid fast bacillus stain was negative. Iliac lymph node biopsy showed reactive sinus histiocytosis with extramedullary hematopoeisis. Thus, diagnosis of pediatric idiopathic primary myelofibrosis was made. Idiopathic pediatric myelofibrosis should be suspected in a child with progressive pallor, hepatosplenomegaly and dry tap on bone marrow aspiration and marrow fibrosis on bone biopsy, after exclusion of secondary causes.

Primary myelofibrosis: 2014 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm characterized by stem cell-derived clonal myeloproliferation, abnormal cytokine expression, bone marrow fibrosis, anemia, splenomegaly, extramedullary hematopoiesis (EMH), constitutional symptoms, cachexia, leukemic progression, and shortened survival.

DIAGNOSIS

DIAGNOSIS is based on bone marrow morphology. The presence of JAK2, CALR, or MPL mutation is supportive but not essential for diagnosis; approximately 90% of patients carry one of these mutations and 10% are "triple-negative." None of these mutations are specific to PMF and are also seen in essential thrombocythemia (ET). Prefibrotic PMF mimics ET in its presentation and the distinction, enabled by careful bone marrow morphological examination, is prognostically relevant. Differential diagnosis also includes chronic myeloid leukemia, myelodysplastic syndromes, chronic myelomonocytic leukemia, and acute myeloid leukemia.

RISK STRATIFICATION

The Dynamic International Prognostic Scoring System-plus (DIPSS-plus) uses eight predictors of inferior survival: age >65 years, hemoglobin <10 g/dL, leukocytes >25 × 10(9) /L, circulating blasts ≥1%, constitutional symptoms, red cell transfusion dependency, platelet count <100 × 10(9) /L, and unfavorable karyotype (i.e., complex karyotype or sole or two abnormalities that include +8, -7/7q-, i(17q), inv(3), -5/5q-, 12p-, or 11q23 rearrangement). The presence of 0, 1, "2 or 3," and ≥4 adverse factors defines low, intermediate-1, intermediate-2, and high-risk disease with median survivals of approximately 15.4, 6.5, 2.9, and 1.3 years, respectively. High risk disease is also defined by CALR(-) /ASXL1(+) mutational status.

RISK-ADAPTED THERAPY

Observation alone is adequate for asymptomatic low/intermediate-1 risk disease, especially with CALR(+) /ASXL1(-) mutational status. Stem cell transplant is considered for DIPSS-plus high risk disease or any risk disease with CALR(-) /ASXL1(+) mutational status. Investigational drug therapy is reasonable for symptomatic intermediate-1 or intermediate-2 risk disease. Splenectomy is considered for drug-refractory splenomegaly. Involved field radiotherapy is most useful for post-splenectomy hepatomegaly, non-hepatosplenic EMH, PMF-associated pulmonary hypertension, and extremity bone pain.

Complex karyotype in a polycythemia vera patient with a novel SETD1B/GTF2H3 fusion gene

The patient had been diagnosed with polycythemia vera (PV) in 1999, at the age of 61, according to the criteria of the Polycythemia Vera Study Group (PVSG) on the basis of the increased red cell mass by isotope determination, normal oxygen saturation, low plasma erythropoietin level, presence of endogenous erythroid colonies (EEC), and splenomegaly. Histopathology of bone marrow biopsy was also consistent with polycythemia vera with no evidence of increased reticulin fibrosis. A karyotype analysis was not performed at that time. He had been treated initially with phlebotomies and then with hydroxyurea with the aim to obtain a better control of hematocrit; he was under low-dose aspirin. In 2009, 10 years after the diagnosis, while the patient was still being treated with hydroxyurea and phlebotomies, he noticed worsening of general conditions and fatigue, and the appearance of night sweats; he also reported that his spleen volume had increased rapidly in the past few months. He complained of severe pruritus especially after (but not limited to) a shower. He was referred to our center for further evaluation. At presentation, his blood counts were as follows: hemoglobin 157 g/L, hematocrit 54.7%, leukocytes 13.1 × 10⁹ /L, platelets 238 × 10⁹ /L, LDH 856 U/L (normal upper limit, 250 U/L). Blood film examination showed neutrophilia (8.9 × 10⁹ /L) but immature myeloid cells and nucleated erythroblasts were absent. The spleen was 14 cm below the left costal margin, the liver was at 4 cm below the right costal margin. He was found to harbor the JAK2V617F mutation with an allele burden of 85% and the circulating CD34⁺ cell count was 14 × 10⁶ /L. A bone marrow biopsy showed the presence of hyperplasia of myeloid and erythroid lineages, increased number of scattered megakarocytes without overt morphologic abnormalities; reticulin fibrosis was grade 1 according to the European classification. On these basis, we considered the patient as presenting the features of PV according to the 2008 WHO classification of myeloid neoplasms associated with grade 1 reticulin fibrosis.

Polyploidy in myelofibrosis: analysis by cytogenetic and SNP array indicates association with advancing disease

Background

Myelofibrosis occurs as primary myelofibrosis or as a late occurrence in the evolution of essential thrombocythaemia and polycythaemia vera. It is the rarest of the three classic myeloproliferative neoplasms (MPN). Polyploidy has only rarely been reported in MPN despite the prominent involvement of abnormal megakaryocytes. The use of peripheral blood samples containing increased numbers of haematopoietic progenitors has improved the output from cytogenetic studies in myelofibrosis and together with the use of single nucleotide polymorphism arrays (SNPa) has contributed to an improved knowledge regarding the diverse genetic landscape of this rare disease.

Results

Cytogenetic studies performed on a consecutive cohort of 42 patients with primary or post ET/PV myelofibrosis showed an abnormal karyotype in 24 cases and of these, nine showed a polyploid clone. Six of the nine cases showed a tetraploid (4n) subclone, whereas three showed mixed polyploid subclones with both tetraploid and octoploid (4n/8n) cell lines. The abnormal clone evolved from a near diploid karyotype at the initial investigation to a tetraploid karyotype in follow-up cytogenetic analysis in four cases. In total, six of the nine polyploid cases showed gain of 1q material. The remaining three cases showed polyploid metaphases, but with no detectable structural karyotypic rearrangements. Three of the nine cases showed chromosome abnormalities of 6p, either at diagnosis or later acquired. SNPa analysis on eight polyploid cases showed additional changes not previously recognised by karyotype analysis alone, including recurring changes involving 9p, 14q, 17q and 22q. Except for gain of 1q, SNPa findings from the polyploid group compared to eight non-polyploid cases with myelofibrosis found no significant differences in the type of abnormality detected.

Conclusions

The study showed the use of peripheral blood samples to be suitable for standard karyotyping evaluation and DNA based studies. The overall profile of abnormalities found were comparable with that of post-MPN acute myeloid leukaemia or secondary myelodysplastic syndrome and cases in the polyploidy group were associated with features of high risk disease. The above represents the first documented series of polyploid karyotypes in myelofibrosis and shows a high representation of gain of 1q.

Thalidomide treatment in a myelofibrosis patient with leukemia transformation

Primary myelofibrosis is a clonal disease of chronic myeloproliferative neoplasm, and is a progressive clinical course with short median survival of less than 5 years after diagnosis. Leukemic transformation occurs in 8-23 % of myelofibrosis patients, and survival is about 3 months after transformation to leukemia. Thalidomide, an oral immunomodulatory drug, has been used effectively in the treatment of primary myelofibrosis, in which some patients could become transfusion independent, and showed improvement in thrombocytopenia and reduction in spleen size. Here, we report a patient with primary myelofibrosis with leukemic transformation who survived for more than 6 years with thalidomide monotherapy. Thalidomide may be beneficial for some myelofibrosis patients with leukemic transformation for whom intensive chemotherapy is not indicated.

Morphologic and cytogenetic differences between post-polycythemic myelofibrosis and primary myelofibrosis in fibrotic stage

Polycythemia vera and primary myelofibrosis share a propensity to progress toward a myelofibrotic late stage with overlapping clinical characteristics. Bone marrow features potentially useful for distinguishing the two entities have not been thoroughly investigated and, currently, clinical history is used for purposes of disease classification. This study describes in detail the morphologic features of 23 cases of post-polycythemic myelofibrosis and 15 cases of primary myelofibrosis with a similar degree of fibrosis, from two large medical centers. Cytogenetic results were available in 19 post-polycythemic myelofibrosis and in 13 primary myelofibrosis cases. JAK2 status and follow-up information was available in all cases. Cellularity was increased in both groups, but more so in post-polycythemic myelofibrosis than in primary myelofibrosis. In post-polycythemic myelofibrosis, most megakaryocytes retained polycythemia vera-like features including normally folded and/or hyperlobulated nuclei devoid of severe maturation defects; only in a few cases were rare tight clusters present. In primary myelofibrosis cases, megakaryocytes showed pronounced anomalies, including increased nuclear:cytoplasmic ratio, abnormal clumping of chromatin and frequent tight clustering. No differences in blast number (<1%) or in the myeloid:erythroid ratio were observed. Post-polycythemic myelofibrosis showed a higher degree of karyotypic alterations and higher percentage of cases with complex karyotype and/or two or more clones. Chromosome 1 defects were common in post-polycythemic myelofibrosis, whereas isolated del(20q) was the most common alteration in primary myelofibrosis. No survival differences were noted between the two groups. Post-polycythemic myelofibrosis cases retain a distinct megakaryocytic morphology that represents a useful clue for differential diagnosis. In addition, they more often display a complex karyotype than do primary myelofibrosis cases. These results suggest that myelofibrosis in polycythemia vera represents a form of progression characterized by profound genetic damage whereas in primary myelofibrosis it is an intrinsic part of the phenotypic manifestation of the disease, not necessarily associated with adverse cytogenetics.

Clinical Correlates of Autosomal Chromosomal Abnormalities in an Electronic Medical Record-Linked Genome-Wide Association Study: A Case Series

Although mosaic autosomal chromosomal abnormalities are being increasingly detected as part of high-density genotyping studies, the clinical correlates are unclear. From an electronic medical record (EMR)–based genome-wide association study (GWAS) of peripheral arterial disease, log-R-ratio and B-allele-frequency data were used to identify mosaic autosomal chromosomal abnormalities including copy number variation and loss of heterozygosity. The EMRs of patients with chromosomal abnormalities and those without chromosomal abnormalities were reviewed to compare clinical characteristics. Among 3336 study participants, 0.75% (n = 25, mean age = 74.8 ± 10.7 years, 64% men) had abnormal intensity plots indicative of autosomal chromosomal abnormalities. A hematologic malignancy was present in 8 patients (32%), of whom 4 also had a solid organ malignancy while 2 patients had a solid organ malignancy only. In 50 age- and sex-matched participants without chromosomal abnormalities, there was a lower rate of hematologic malignancies (2% vs 32%, P < .001) but not solid organ malignancies (20% vs 24%, P = .69). We also report the clinical characteristics of each patient with the observed chromosomal abnormalities. Interestingly, among 5 patients with 20q deletions, 4 had a myeloproliferative disorder while all 3 men in this group had prostate cancer. In summary, in a GWAS of 3336 adults, 0.75% had autosomal chromosomal abnormalities and nearly a third of them had hematologic malignancies. A potential novel association between 20q deletions, myeloproliferative disorders, and prostate cancer was also noted.

The clinical importance of moderate/severe bone marrow fibrosis in patients with therapy-related myelodysplastic syndromes

The presence of moderate to severe bone marrow (BM) fibrosis has been shown to be an adverse feature in patients with primary myelodysplastic syndromes (MDS). However, the clinical importance of BM fibrosis is not clear in therapy-related MDS. We retrieved all therapy-related MDS (t-MDS) cases (n = 266) diagnosed at our hospital over a 10-year period (2003-2012). Reticulin and trichrome stains were performed in cases in which BM fibrosis was suspected on initial evaluation of hematoxylin and eosin-stained slide. BM fibrosis was graded according to European consensus guidelines, and a score of MF2/MF3 was defined as moderate/severe fibrosis. Moderate/severe BM fibrosis was found in 47 (17%) patients. Compared to 219 patients with no/mild BM fibrosis, the patients with moderate/severe fibrosis presented with severer thrombocytopenia (p = 0.039) and higher numbers of circulating blasts (p = 0.051) but with similar degrees of anemia and neutropenia, transfusion requirements, and similar incidences of hepatosplenomegaly and constitutional symptoms. Histological examination revealed a comparable BM cellularity and BM blast percentage, but markedly increased megakaryocytes (p < 0.001) in the fibrotic group. Although the risk distribution of cytogenetic data was similar according to the New Comprehensive Cytogenetic Scoring criteria, -5 and -17 were more frequently observed in t-MDS with moderate/severe BM fibrosis (p = 0.031 and p = 0.043, respectively). With a median follow-up of 11.5 months, patients with moderate/severe BM fibrosis showed a similar risk of acute myeloid leukemia transformation and a comparable overall survival in univariate and multivariate analyses. Moderate/severe BM fibrosis in patients with t-MDS is associated with certain clinicopathological and genetic features. However, unlike the situation in patients with primary MDS, moderate/severe BM fibrosis does not add additional risk to patients with therapy-related MDS.

Array comparative genomic hybridization and sequencing of 23 genes in 80 patients with myelofibrosis at chronic or acute phase

Myelofibrosis is a myeloproliferative neoplasm that occurs de novo (primary myelofibrosis) or results from the progression of polycythemia vera or essential thrombocytemia (hereafter designated as secondary myelofibrosis or post-polycythemia vera/ essential thrombocythemia myelofibrosis). To progress in the understanding of myelofibrosis and to find molecular prognostic markers we studied 104 samples of primary and secondary myelofibrosis at chronic (n=68) and acute phases (n=12) from 80 patients, by using array-comparative genomic hybridization and sequencing of 23 genes (ASXL1, BMI1, CBL, DNMT3A, EZH2, IDH1/2, JAK2, K/NRAS, LNK, MPL, NF1, PPP1R16B, PTPN11, RCOR1, SF3B1, SOCS2, SRSF2, SUZ12, TET2, TP53, TRPS1). We found copy number aberrations in 54% of samples, often involving genes with a known or potential role in leukemogenesis. We show that cases carrying a del(20q), del(17) or del(12p) evolve in acute myeloid leukemia (P=0.03). We found that 88% of the cases were mutated, mainly in signaling pathway (JAK2 69%, NF1 6%) and epigenetic genes (ASXL1 26%, TET2 14%, EZH2 8%). Overall survival was poor in patients with more than one mutation (P=0.001) and in patients with JAK2/ASXL1 mutations (P=0.02). Our study highlights the heterogeneity of myelofibrosis, and points to several interesting copy number aberrations and genes with diagnostic and prognostic impact.

MPN patients harbor recurrent truncating mutations in transcription factor NF-E2

The molecular etiology of myeloproliferative neoplasms (MPNs) remains incompletely understood, despite recent advances incurred through the discovery of several different mutations in MPN patients. We have recently described overexpression of the transcription factor NF-E2 in MPN patients and shown that elevated NF-E2 levels in vivo cause an MPN phenotype and predispose to leukemic transformation in transgenic mice. We report the presence of acquired insertion and deletion mutations in the NF-E2 gene in MPN patients. These result in truncated NF-E2 proteins that enhance wild-type (WT) NF-E2 function and cause erythrocytosis and thrombocytosis in a murine model. NF-E2 mutant cells acquire a proliferative advantage, witnessed by clonal dominance over WT NF-E2 cells in MPN patients. Our data underscore the role of increased NF-E2 activity in the pathophysiology of MPNs.

TET2 Expression in Bone Marrow Mononuclear Cells of Patients with Myelodysplastic Syndromes and Its Clinical Significances

Objective

To investigate the expression of TET2 mRNA and protein in the bone marrow mononuclear cells (BMMNC) of patients with myelodysplastic syndrome (MDS) and its clinical significance.

Methods

The expression of TET2 mRNA and protein in bone marrow mononuclear cells (BMMNC) of 32 patients with MDS and 20 healthy donors was examined by qPCR and Western blot.

Results

The expression of TET2 mRNA in BMMNC was down-regulated in MDS patients compared with the donor group [(0.41±0.28)% vs. (1.07±0.56)%] (P<0.001). Compared with lower expression group (TET2<0.4) [(6.53±6.17)%], patients with higher expression of TET2 (≥0.4) presented significantly lower proportion of bone marrow blasts [(1.21±1.56)%] (P<0.05). The expression of TET2 mRNA in BMMNC of MDS patients was inversely correlated with malignant clone burden (r=-0.398, P<0.05) and IPSS (r=-0.412, P<0.05). The expression of TET2 protein was down-regulated in MDS patients compared with that in the donor group.

Conclusions

The mRNA and protein expression of TET2 in BMMNC of MDS patients is decreased, which might be useful as an important parameter for the evaluation of MDS clone burden.

Differential diagnosis of myelofibrosis based on WHO 2008 criteria: acute panmyelosis with myelofibrosis, acute megakaryoblastic leukemia with myelofibrosis, primary myelofibrosis and myelodysplastic syndrome with myelofibrosis

INTRODUCTION

The aim of this study was to characterize clinicopathological features of acute panmyelosis with myelofibrosis (APMF), acute megakaryoblastic leukemia with myelofibrosis (AMKL-MF), primary myelofibrosis (PMF) and myelodysplastic syndrome with myelofibrosis (MDS-MF) in order to provide the keys to the differential diagnosis of bone marrow (BM) fibrosis.

METHODS

We compared age, gender, splenomegaly, serum lactate dehydrogenase level, blood cell counts, blast counts in peripheral blood (PB) and BM, megakaryocyte counts, BM cellularity, dysplasia, and the karyotypes of patients with APMF (n = 6), AMKL-MF (n = 7), PMF (n = 44), and MDS-MF (n = 44).

RESULTS

APMF showed hyperplasia of all three lineages, increase in megakaryocyte count with dysplasia and frequent abnormal karyotypes. AMKL-MF was associated with elevated BM blast counts, decreased BM megakaryocyte count with rare megakaryocytic dysplasia and chromosome 21 abnormality. PMF patients displayed splenomegaly, rare blasts in PB/BM, and JAK2 V617F mutation. MDS-MF patients showed pancytopenia, dysplasia in all three lineages and recurrent chromosomal abnormalities involving chromosome 5,7,12, and 17.

CONCLUSIONS

Although differential diagnosis among APMF, AMKL-MF, PMF, and MDS-MF is very challenging due to the overlapping clinical and morphological features, meticulous investigation of the patient with respect to splenomegaly, blood cell count, PB and BM findings, and karyotype will serve as a guide to correct diagnosis.

Myelofibrosis in Philadelphia chromosome-negative myeloproliferative neoplasms is associated with aberrant karyotypes

In Philadelphia chromosome-negative myeloproliferative neoplasms (Ph¯ MPN), non-specific chromosomal defects are detectable and essential thrombocythemia (ET) has the lowest rate of aberrations, whereas primary myelofibrosis (PMF) and post-polycythemia vera (PV) myelofibrosis have the highest rates of aberrations. The frequency of cytogenetic defects in pre-fibrotic stage PMF has not been characterized thus far and the underlying molecular defects of chromosomal instability are unknown. In this study, histopathological findings were correlated with cytogenetic data (n = 249). The expression of DNA repair factors ERCC1 and LIG4 were determined in Ph¯ MPN with and without cytogenetic aberrations. Pre-fibrotic PMF and ET have similarly low frequencies of karyotype anomalies. The expression of ERCC1, but not LIG4, is increased in fibrotic stage PMF but is not associated with accumulation of cytogenetic defects. In conclusion, aberrant karyotypes in Ph¯ MPN reflect the chromosomal instability in these diseases and, in comparison with pre-fibrotic stages, Ph¯ MPN with fibrosis has the highest frequency of cytogenetic aberrations.

Development of monocytosis in patients with primary myelofibrosis indicates an accelerated phase of the disease

Primary myelofibrosis is a type of chronic myeloproliferative neoplasm characterized by progressive bone marrow failure with worsening cytopenia and in a subset of patients, progression to acute leukemia. Published data in patients with myelodysplastic syndromes have shown that the development of monocytosis in the course of myelodysplastic syndromes is associated with a poor prognosis. A similar occurrence has been only sporadically reported in patients with primary myelofibrosis. Over a period of four years we identified 10 out of 237 cases of primary myelofibrosis who developed persistent absolute monocytosis (>1 × 10(9)/l) during the course of disease (5 men and 5 women; median age/range: 68 years/52-82). Monocytosis developed at a median interval of 42 months from diagnosis (range: 1-180) and persisted for a median period of 23 months (range: 2-57). Five patients died after developing monocytosis (range: 20-188 months) and two experienced worsening disease and became transfusion dependent. Monocytosis was associated with increased white blood cells, decreased hemoglobin, decreased platelet count, and the presence of circulating blasts. In three cases, bone marrow biopsies after the onset of monocytosis showed marked myelomonocytic proliferation with morphological shifting from a typical primary myelofibrosis marrow appearance to aspects compatible with an overt 'secondary' chronic myelomonocytic leukemia. Before the development of monocytosis, 5 of 10 patients carried the JAK2V617F mutation; five patients showed karyotypic alterations. No change in JAK2 mutational status or cytogenetic evolution were associated with the development of monocytosis. Four of nine patients analyzed showed KRAS mutation in codon 12 or 13 with low allele burden. This is the first study correlating monocytosis developing in primary myelofibrosis patients with bone marrow morphology, laboratory data, molecular analysis and clinical follow-up. Development of monocytosis in patients with established primary myelofibrosis is associated with rapid disease progression and these patients should be considered as a high-risk group associated with short survival.

Primary myelofibrosis: 2013 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm characterized by stem cell-derived clonal myeloproliferation, abnormal cytokine expression, bone marrow fibrosis, anemia, splenomegaly, extramedullary hematopoiesis (EMH), constitutional symptoms, cachexia, leukemic progression, and shortened survival.

DIAGNOSIS

Diagnosis is based on bone marrow morphology. The presence of fibrosis, JAK2/MPL mutation, or +9/13q- cytogenetic abnormality is supportive but not essential for diagnosis. Prefibrotic PMF mimics essential thrombocythemia in its presentation and the distinction is prognostically relevant. Differential diagnosis of myelofibrosis should include chronic myeloid leukemia, myelodysplastic syndromes, chronic myelomonocytic leukemia, and acute myeloid leukemia.

RISK STRATIFICATION

The Dynamic International Prognostic Scoring System-plus (DIPSS-plus) prognostic model for PMF can be applied at any point during the disease course and uses eight independent predictors of inferior survival: age >65 years, hemoglobin <10 g/dL, leukocytes >25 × 10⁹/L, circulating blasts ≥ 1%, constitutional symptoms, red cell transfusion dependency, platelet count <100 × 10⁹/L, and unfavorable karyotype (i.e., complex karyotype or sole or two abnormalities that include +8, -7/7q-, i(17q), inv(3), -5/5q-, 12p-, or 11q23 rearrangement). The presence of 0, 1, "2 or 3," and ≥ 4 adverse factors defines low, intermediate-1, intermediate-2, and high-risk disease with median survivals of approximately 15.4, 6.5, 2.9, and 1.3 years, respectively. A >80% two-year mortality is predicted by monosomal karyotype, inv(3)/i(17q) abnormalities, or any two of circulating blasts >9%, leukocytes ≥ 40 × 10⁹/L or other unfavorable karyotype. Most recently, mutations involving ASXL1, SRSF2, EZH2, and IDH1/2 or increased plasma IL-2R, IL-8, or serum-free light chain levels have been shown to adversely affect survival.

RISK-ADAPTED THERAPY

Observation alone is adequate for asymptomatic low/intermediate-1 risk disease. Allogeneic stem cell transplantation (ASCT) is often considered for high risk disease. Conventional or experimental drug therapy is reasonable for symptomatic intermediate-1 or intermediate-2 risk disease; however, ASCT is an acceptable treatment option for such patients in the presence of ASXL1 or other prognostically adverse mutations. Splenectomy and low-dose radiotherapy are used for drug-refractory splenomegaly. Radiotherapy is also used for the treatment of non-hepatosplenic EMH, PMF-associated pulmonary hypertension, and extremity bone pain.

Clinical, histopathologic, and genetic features of pediatric primary myelofibrosis--an entity different from adults

Primary myelofibrosis is a chronic myeloproliferative neoplasm characterized by cytopenias, leukoerythroblastosis, extramedullary hematopoiesis, hepatosplenomegaly and bone marrow fibrosis. Primary myelofibrosis is a rare disorder in adults; children are even less commonly affected by this entity, with the largest pediatric case series reporting on three patients. Most literature suggests spontaneous resolution of myelofibrosis without long term complications in the majority of affected children. We describe the clinical, pathologic, and molecular characteristics and outcomes of nineteen children with primary myelofibrosis treated in our center from 1984 to 2011. Most patients had cytopenia significant enough to require supportive therapy. No child developed malignant transformation and only five of the 19 children (26%) had spontaneous resolution of disease. Sequence analyses for JAK2V617F and MPLW515L mutations were performed on bone marrow samples from 17 and six patients, respectively, and the results were negative. In conclusion, analysis of this large series of pediatric patients with primary myelofibrosis demonstrates distinct clinical, hematologic, bone marrow, and molecular features from adult patients.

A novel murine model of myeloproliferative disorders generated by overexpression of the transcription factor NF-E2

Mice expressing a transgene encoding the transcription factor NF-E2 in hematopoietic cells exhibit features of myeloproliferative neoplasms, including thrombocytosis, Epo-independent colony formation, stem and progenitor cell overabundance, leukocytosis, and progression to acute myeloid leukemia.

The molecular pathophysiology of myeloproliferative neoplasms (MPNs) remains poorly understood. Based on the observation that the transcription factor NF-E2 is often overexpressed in MPN patients, independent of the presence of other molecular aberrations, we generated mice expressing an NF-E2 transgene in hematopoietic cells. These mice exhibit many features of MPNs, including thrombocytosis, leukocytosis, Epo-independent colony formation, characteristic bone marrow histology, expansion of stem and progenitor compartments, and spontaneous transformation to acute myeloid leukemia. The MPN phenotype is transplantable to secondary recipient mice. NF-E2 can alter histone modifications, and NF-E2 transgenic mice show hypoacetylation of histone H3. Treatment of mice with the histone deacetylase inhibitor (HDAC-I) vorinostat restored physiological levels of histone H3 acetylation, decreased NF-E2 expression, and normalized platelet numbers. Similarly, MPN patients treated with an HDAC-I exhibited a decrease in NF-E2 expression. These data establish a role for NF-E2 in the pathophysiology of MPNs and provide a molecular rationale for investigating epigenetic alterations as novel targets for rationally designed MPN therapies.