The clinical presentation may be either insidious or abrupt. Most common symptoms are night sweats, unexplained fever of > 37.5°C and weight loss of more than 10% in the last 6 months [9]. Clinical findings may reveal splenomegaly, which invariably occurs as a result of extramedullary hematopoiesis [8]. GI irritation, portal hypertension and profuse weakness that leads to decreased physical activity are also encountered and are substantial causes of morbidity [8].

• Splenomegaly

  Our present case suggests the potential risk of TLS development after ruxolitinib treatment, particularly in patients with massive splenomegaly. [ncbi.nlm.nih.gov]

  The risk factors for post-PV MF transformation included WBC count 13 x 109/L, platelet count 550 109/L and splenomegaly at diagnosis of PV. [ash.confex.com]

  Progression of polycythemia vera characterized by decreased erythropoiesis and granulopoiesis, reticulin and collagen fibrosis of the bone marrow, leucoerythroblastic reaction in the peripheral blood, poikilocytosis, tear-drop shaped red blood cells, and splenomegaly [mycancergenome.org]

  PV 3 2012 Splenomegaly in myelofibrosis--new options for therapy and the therapeutic potential of Janus kinase 2 inhibitors. [allie.dbcls.jp]

• Palpable Spleen

  spleen size ( P 0.002) in post-PV MF. [nature.com]

  When the study commenced, 13% of patients were red blood cell (RBC) transfusion-dependent and 87% had palpable spleen, with a median size of 13 cm (range 0-18 cm ). [targetedonc.com]

  Increasing splenomegaly 66/67 (98)‡         Palpable spleen more than 5 cm from left costal margin 54 (82)         Appearance of a newly palpable splenomegaly 12 (18)     4. [ashpublications.org]

  Palpable spleen measuring 5 cm below the left lower costal margin or spleen volume of 450 cm3 by MRI or CT scan assessment 3. Confirmed diagnosis of PMF, post–PV-MF, or post–ET-MF according to the World Health Organization (WHO) criteria 4. [clinicaltrialsregister.eu]

• Anemia

  Myelofibrosis patients with ASXL1 lesions were more likely to have received anemia-directed therapy compared to those without lesions [15/26 (58%) versus 11/39 (23%); P 0.02]. [ncbi.nlm.nih.gov]

  However ruxolitinib can also cause risks of treatment-associated anemia and decreases in platelet cells that help blood clot (thrombocytopenia). The rate of discontinuation of ruxolitinib treatment at 1, 2, and 3 years is also high. [rush.edu]

  Anemia (Hg 100 g/L) and age 65 years at diagnosis of post-PV MF were identified as significant risk factors for poor survival of patients with post-PV MF. [ash.confex.com]

  Clinically, patients present with symptoms related to thrombocytosis/leukocytosis, anemia and/or progressive splenomegaly. [springermedizin.de]

• Fatigue

  The result is excessive fibrous (scar) tissue formation in the bone marrow, which can lead to severe anemia, weakness, fatigue and enlarged spleen and liver. The cancer develops when a mutation occurs in the DNA of a single blood forming stem cell. [rush.edu]

  Seventy-one percent of all patients reported fatigue at least once during the intervention period (maximum grade 2) and 50% reported diarrhea (maximum grade 2). Table 2. All reported adverse events (AEs) listed in regard to prevalence. [haematologica.org]

  Symptoms include heart attack, stroke, deep venous thrombosis, Headaches, lack of concentration and fatigue. The disease may be controlled by chemotherapy, transfusions, transplant and medications. [prnewswire.com]

  Subject with evidence of evaluable residual burden of disease following ruxolitinib monotherapy treatment, consisting of: Persistent or worsening disease-related symptoms, including but not limited to fatigue, pruritus, night sweats, early satiety, and [apps.winshipcancer.emory.edu]

  The most commonly reported non-hematologic adverse events (AEs) with ruxolitinib are headache, diarrhea, and fatigue; these are largely low-grade. [mpncanada.com]

• Fever

  The main manifestations of the disease are constitutional complaints such as weakness, malaise, low-grade fever and weight loss, while splenomegaly, as a result of secondary hematopoiesis, is the main clinical finding. [symptoma.com]

  Constitutional symptoms, such as night sweats, pruritus, weight loss and fever may be treated with Jakafi. [mpnresearchfoundation.org]

  Constitutional symptoms include fevers, pruritus, and the one that I find to be the most troubling is early satiety leading to weight loss. Once that starts to develop, patients tend to have a more rapid decline. [onclive.com]

  Other symptoms may include: Fatigue A general feeling of discomfort Difficulty breathing Weight loss Fever and night sweats Anemia Abnormal bleeding Patients with myelofibrosis have an increased risk of bleeding. [stanfordhealthcare.org]

  MF patients can also suffer from debilitating constitutional symptoms, such as drenching night sweats, fatigue, severe itching (pruritus), abdominal pain, fever and bone pain. [geron.com]

• Weight Loss

  loss and other constitutional symptoms. [symptoma.com]

  With regard to symptoms, 43% reported fatigue and 29% reported weight loss during the six months prior to inclusion. Patients’ characteristics and laboratory data at baseline are listed in Table 1. Table 1. Demographic data for included patients. [haematologica.org]

  Constitutional symptoms, such as night sweats, pruritus, weight loss and fever may be treated with Jakafi. [mpnresearchfoundation.org]

  Other symptoms may include: Fatigue A general feeling of discomfort Difficulty breathing Weight loss Fever and night sweats Anemia Abnormal bleeding Patients with myelofibrosis have an increased risk of bleeding. [stanfordhealthcare.org]

  Constitutional symptoms include fevers, pruritus, and the one that I find to be the most troubling is early satiety leading to weight loss. Once that starts to develop, patients tend to have a more rapid decline. [onclive.com]

• Weakness

  The result is excessive fibrous (scar) tissue formation in the bone marrow, which can lead to severe anemia, weakness, fatigue and enlarged spleen and liver. The cancer develops when a mutation occurs in the DNA of a single blood forming stem cell. [rush.edu]

  Dermatomyositis (DM) is an idiopathic autoimmune myopathy characterized by muscle weakness and purple-pigmented rashes. [oncologynurseadvisor.com]

  GI irritation, portal hypertension and profuse weakness that leads to decreased physical activity are also encountered and are substantial causes of morbidity. Patient history is the single most important part of the workup. [symptoma.com]

  Myelofibrosis causes extensive scarring in your bone marrow, leading to severe anemia that can cause weakness and fatigue. It can also cause a low number of blood-clotting cells called platelets, which increases the risk of bleeding. [mayoclinic.org]

  This causes symptoms such as anaemia, fatigue, weakness, and an enlarged spleen. The Jump clinical trial is an expanded access Phase 3b study of Jakavi for the treatment of MF. So far 2,233 MF patients have been involved with Jump. [patientworthy.com]

• Dyspnea

  Grade 3 AEs included anemia (n 3), neutrophil decrease (n 2), amylase increase (n 2), lipase increase (n 2), diarrhea (n 2), colitis (n 1), dyspnea (n 1), pneumonia (n 1), and other infections (n 2). The case of sepsis was the only grade 4 AE. [hematologytimes.com]

  The four most frequent non-hematologic adverse reactions reported at a higher frequency in the Jakavi group than in the BAT group were diarrhea (14.5%), muscle spasm (11.8%), dizziness (11.8%) and dyspnea (10.0%) respectively. [newswire.ca]

  Symptoms and Signs Polycythemia vera itself is often asymptomatic, but eventually the increased red cell volume and viscosity cause weakness, headache, light-headedness, visual disturbances, fatigue, and dyspnea. [msdmanuals.com]

  Symptoms of myelofibrosis, particularly those associated with splenomegaly (abdominal distention and pain, early satiety, dyspnea, and diarrhea) and constitutional symptoms, represent a substantial burden to patients. [haematologica.org]

  Occasionally, increased red cell volume and viscosity cause weakness, headache, light-headedness, visual disturbances, fatigue, and dyspnea. Pruritus often occurs, particularly after a hot bath. The face may be red and the retinal veins engorged. [mpncanada.com]

• Abdominal Pain

  MF patients can also suffer from debilitating constitutional symptoms, such as drenching night sweats, fatigue, severe itching (pruritus), abdominal pain, fever and bone pain. [geron.com]

  A severely enlarged spleen can cause abdominal pain and back pain. Growths in other areas of your body. [mayoclinic.org]

  The ASM SAF assesses the severity of 8 symptoms (pruritus, flushing, spots, nausea, vomiting, diarrhea, abdominal pain, and fatigue) on a 0–10 scale, and 2 items assess the frequency of diarrhea and vomiting. [ascopost.com]

  Symptoms that may develop as PV progresses include headache; dizziness; visual disturbances; severe itching, often triggered by a bath or shower; ruddy (or red) skin tone; abdominal pain; feeling of fullness or bloating in the left upper abdominal area [mpninfo.org]

• Left Upper Quadrant Pain

  TSS of 10 on the MPN-SAF TSS 2.0 or a single symptom score of 5 or two symptoms of 3, including only the symptoms of left upper quadrant pain, bone pain, itching, or night sweats 6. Age 18 years 7. [mountsinai.org]

  TSS of 10 on the MPN-SAF TSS 2.0 or patients with a single symptom score of 5 or two symptoms of 3, including only the symptoms of left upper quadrant pain, bone pain, itching, or night sweats. Age 18 years old. [mayo.edu]

  upper quadrant pain, bone pain, itching, or night sweats b) Or progressive disease any time while on ruxolitinib treatment as defined by any one of the following: • Spleen volume increase by 25% from the nadir as assessed by MRI or CT • Appearance of [clinicaltrialsregister.eu]

• Hepatomegaly

  Presence of diabetes or another neoplasia was associated with higher ROS levels (p 0.05), splenomegaly, hepatomegaly, and peripheral blasts with lower HoloTC levels (p 0.005). [ncbi.nlm.nih.gov]

  The presence of hepatomegaly and splenomegaly was based on physical examination at diagnosis. [tandfonline.com]

  If hepatomegaly occurs, patients might also have variceal bleeding related to portal hypertension or ascites. B. History Part 2: Prevalence: The peak incidence of primary myelofibrosis (PMF) is between 50-70 years of age. [clinicaladvisor.com]

  Hepatomegaly. Pallor. Petechiae and ecchymosis. Neutropenia may cause opportunistic infection - eg, oral thrush. Lymphadenopathy. Signs of portal hypertension. Gout. [patient.info]

  Less common symptoms associated with polycythemia vera include a tendency to bruise easily, frequent nosebleeds or bleeding from the gums, enlargement of the liver (hepatomegaly), and erythromelalgia, a condition characterized by a reddened or purplish [rarediseases.org]

• Night Sweats

  TSS of 10 on the MPN-SAF TSS 2.0 or a single symptom score of 5 or two symptoms of 3, including only the symptoms of left upper quadrant pain, bone pain, itching, or night sweats 6. Age 18 years 7. [mountsinai.org]

  Subject with evidence of evaluable residual burden of disease following ruxolitinib monotherapy treatment, consisting of: Persistent or worsening disease-related symptoms, including but not limited to fatigue, pruritus, night sweats, early satiety, and [apps.winshipcancer.emory.edu]

  TSS of 10 on the MPN-SAF TSS 2.0 or patients with a single symptom score of 5 or two symptoms of 3, including only the symptoms of left upper quadrant pain, bone pain, itching, or night sweats. Age 18 years old. [mayo.edu]

  […] fatigue, fever, night sweats and weight loss. [mpnresearchfoundation.org]

  So, malfunctioning bone marrow, anemia—low platelets in some patients—and low white cell count coupled with a very large spleen, enlargement of the liver, and very poor quality of life—bone aches and pains, night sweating, low-grade fevers, itching, night [onclive.com]

• Pierre Robin Syndrome

  ROBIN SYNDROME Zie ook: JAW DEVELOPMENT CONDITION Catel Manzke Syndrome Entry provided by the National Org. for Rare Diseases describes this hyperphalangy variant of the condition. [catsclem.nl]

Patient history is the single most important part of the workup. A prior diagnosis of PV should definitely raise suspicion of post-PV myelofibrosis in the setting of constitutional symptoms. Erythrocytosis may develop in numerous physiological and pathological conditions (e.g. hypoxic states, various malignancies, use of erythropoietin, renal disease, etc). For this very reason, specific diagnostic criteria have been proposed [2] [3]:

• Major criteria - Levels of hemoglobin > 18.5 g/dL in men and > 16.5 g/dL in women, indications of increased red cell volume (markedly increased hematocrit, elevated red cell mass greater than 25% above mean normal predicted value), or presence of V617F or other similar JAK mutations.
• Minor criteria - EPO levels below normal values, endogenous production of erythroid colonies in vitro (in the absence of EPO), or hypercellularity and prominent proliferation of erythroid, granulocytic and megakaryocytic lineages shown on bone marrow biopsy (known as panmyelosis) [10].

To confirm PV, either two major and one minor or one major and two minor criteria are necessary and a 97% success rate is predicted with this criteria [3]. In addition to PV, moderate-to-severe fibrosis of the bone marrow (2–3 on 0–3 scale or grade 3–4 on 0–4 scale) is a diagnostic hallmark of post-PV MF, while clinical findings such as splenomegaly and constitutional symptoms further support these findings [9].

• Decreased Platelet Count

  Anagrelide may also be used to decrease platelet counts. Prognosis PV is a chronic disease. [orpha.net]

  Decreasing platelet counts in ET to below 600 x 10 9 /L can decrease thrombotic complications. 46 High platelet counts ( 1,000 x 10 9 /L) are associated with acquired von Willebrand disease resulting from the adsorption of von Willebrand multimers onto [clevelandclinicmeded.com]

• Prolonged QT Interval

  heart failure, hypokalemia [defined as serum potassium 3.0 mEq/L that is persistent and refractory to correction], family history of long QT interval syndrome, or concomitant use of medications that may prolong QT interval). [mayo.edu]

• Torsades De Pointes

  de Pointes within 1 week or 5 half-lives (whichever is longer) prior to Cycle 1 Day 1. [apps.winshipcancer.emory.edu]

Until recently, palliative care through splenectomy, radiotherapy and use of various drugs (hydroxyurea, Thalidomide alkylating agents) have neither relieved symptoms nor prevented complications. [8]. Allogeneic hematopoietic stem cell transplant has shown to be the only potentially curative mode of therapy for patients with any form of myelofibrosis, but numerous challenges are faced when opting for this procedure - presence of one or more comorbidities due to advanced age of patients, optimal timing and a very limited number of suitable donors [11]. Recent introduction of JAK inhibitors in clinical practice has dramatically reduced the severity of symptoms, as a 45% reduction rate in post-PV MF was achieved through the use of ruxolitinib, a JAK2 and JAK1 inhibitor [11]. Drugs such as tasocitinib, lestaurtinib, pacritinib and several others have shown to significantly reduce the activity of various growth factors and pro-inflammatory cytokines and are undergoing phased clinical trials. [11]. Namely, ruxolitinib and other JAK2 inhibitors are potent inducers of anemia and thrombocytopenia that may be life-threatening for patients who present with lower RBC and platelet counts, which is why careful evaluation must be conducted prior to their administration [11]. Unfortunately, studies have so far concluded that the use of JAK2 inhibitors does not prolong survival rates of patients in a significant manner, but further research is necessary to determine their optimal utilization [11].

Several reports have been published stating that less than 10% of patients progress to MF from PV [15], whereas a 15-year risk of PV progression to post-PV MF is around 6%, with an incidence rate of 5.1 per 1000 person years [6]. Other authors, however, suggest that the incidence rate of post-PV MF is up to 14% [15]. Although marked differences exist in patient outcomes, ranging from 1-10+ years [16], progressive hemoglobin and platelet reduction eventually develops in most cases and carries a poor prognosis, as median survival rates of 5.7-8 years are determined [6] [7]. Consequently, the severity of anemia implies worse outcomes, as does splenomegaly and findings of ≥ 10% blasts in peripheral blood or bone marrow [7] [16].

PV belongs to the group of "BCR-ABL1-negative" myeloproliferative diseases (MPNs), together with essential thrombocythemia and primary myelofibrosis, which turned the attention to other etiologic mechanisms [11]. In the past decade, two key mutations of the JAK2 molecule on chromosome 9 have been identified - substitution of valine to phenylalanine at amino acid position 617 (V617F) and exon 12 mutations (seen only in about 2-3% of PV cases) [2] [4]. Although the vast majority of patients are heterozygous for JAK2V617F, homozygous mutations through a phenomenon of uniparental disomy have also been discovered in some individuals [11]. Although JAK2 mutations are a constitutive finding in post-PV MF, it is hypothesized that they are not the only factors involved in the pathogenesis and some other genetic events are presumably involved as well [11] [12].

Large-scale European studies have established a prevalence of PV between 0.4-2.8 per 100,000 individuals per year, suggesting that it is rarely encountered in clinical practice [13]. Myelofibrosis (regardless of the underlying cause) has shown an even lower rate of occurrence: 0.1-1 per 100,000 individuals per year [13]. United States, on the other hand, has much higher prevalence rates of PV : 44-57 per 100,000 individuals. Unlike studies conducted in Europe, the rates of post-PV MF have been identified in the United States [5]. Namely, between 0.3-0.7 per 100,000 individuals develop this myeloproliferative disorder [5]. Most patients are either older adults or belong to the elderly population [6], supported by the fact that less than 20% of patients are < 50 years old [14]. Gender predilection is currently not determined. PV patients who are older than 60 years and have a history of previous thrombosis, as well as thrombocytosis are considered to be at greatest risk for development of myelofibrosis [3] [7], whereas a WBC count of > 15 × 109/L at the diagnosis of PV is a significant predictor of evolution of post-PV MF [6].

Under physiological circumstances, the JAK-STAT signaling pathway is crucial for he development of various cell lineages and functions of the immune system. More specifically, JAK2 is an essential component of EPO, granulocyte-macrophage colony stimulating factor (GM-CSF), thrombopoietin, growth hormone and interleukins 3 and 5 signaling [11], whereas signal transducers and activators of transcription (STAT) are the next step of the signaling cascade, resulting in expression of genes that trigger proliferation, migration differentiation and angiogenesis of numerous lineages [11]. Additionally, numerous pro-inflammatory cytokines, such as IL-12, IL-1, IL-6 (in addition to IL-3 and 5), have shown to be influenced by the JAK/STAT pathway, which could explain why myelofibrosis patients in general are in a hypercatabolic state and thus trigger chronic weight loss and other constitutional symptoms [11]. The pathogenesis of post-PV MF starts with enhanced gene expression as a result of hypersensitivity of JAK2 to cytokine signaling [4] [11], inducing aberrant production of erythrocytes, megakaryocytes and granulocytes [6] Upregulated gene expression occurs due to phosphorylation of proteins and a gain-of-function mutation that creates a profoundly more active JAK/STAT signaling pathway, hematopoietic proliferation [11].

Since myelofibrosis is considered to be a progression of PV, screening for JAK2 mutations may be of significant benefit in determining the possibility of post-PV MF [3]. Although much has been discovered in terms of pathogenesis, prevention of post-PV MF is currently not possible.

Myelofibrosis is considered to be a severe and life-threatening clonal hematopoietic stem cell malignancy that arises from primary hematologic diseases and secondary causes - essential thrombocytosis and polycythemia vera (PV), a disease primarily encountered in older patients (> 50 years) that is characterized by abnormal production of erythrocytes, platelets and granulocytes in the absence of an apparent physiologic stimulus [1] [2]. Until recently, the exact reason why PV can progress to myelofibrosis (now known as post-polycythemia vera myelofibrosis, or post-PV MF) was unknown, but studies have determined that mutations of janus kinase 2 (JAK2), a cytoplasmic signaling molecule, were identified in more than 95% of patients [3]. The V617F JAK mutation leads to hypersensitivity of bone marrow cells to erythropoietin (EPO) and several proliferative cytokines [4], leading to aberrant production of primarily erythrocytes, but also megakarocytes and granulocytes. Over time, constant stimulation of hematopoietic differentiation damages the bone marrow and causes extensive fibrosis, the hallmark of post-PV MF. Although it is considered to be a rare disease, with estimated prevalence rates of 0.3-0.7 per 100,000 individuals in the United States [5], early recognition is of vital importance in prolonging the life of the patient since survival rates range between 5-8 years from the time of diagnosis [6] [7]. The main manifestations of the disease are constitutional complaints such as weakness, malaise, low-grade fever and weight loss, while splenomegaly, as a result of secondary hematopoiesis [8], is the main clinical finding [9]. To make the diagnosis of post-PV MF, it is imperative to obtain a detailed patient history and confirm PV, followed by laboratory studies and bone marrow biopsy that will show panmyelosis [10]. Splenectomy, use of various immunomodulating drugs and palliative care have been used in these patients as main forms of therapy until the introduction of JAK inhibitors, which significantly reduce the burden of clinical symptoms [11]. Survival rates remain unchanged in these agents, however, and the only potentially curative procedure is allogeneic hematopoietic stem cell transplantation, but numerous risks (older age, co-morbidities, suitability of donors) impair its more frequent use [11]. Because myelofibrosis occurring on the grounds of PV may be fatal within several years, screening of at-risk patients for JAK2 mutations is advisable, so that early recognition of the disease may be possible [3].

Post-polycythemia vera myelofibrosis (post-PV MF) is a term that describes the evolution of polycythemia vera (a disorder of abnormal production of red and white blood cells, as well as platelets) into a malignant disease in which genetic mutations lead to profound stimulation of further cell production, ultimately causing scarring of the bone marrow. Until recently, the exact reason why this pathological event occurred was unknown. Now mutations of signaling molecules (JAK2) that stimulate cytokines and growth factors that promote cell production from the bone marrow have been identified in more than 95% of patients. This condition is most frequently diagnosed in older adults (> 60 years) and approximately 0.3-0.7 per 100,000 individuals develop post-PV MF in the United States. As a result of profound proliferation of cells from the bone marrow, inflammatory cytokines concentrations are released causing constitutional symptoms such as fatigue, weakness, weight loss, night sweats and low-grade fever. Additionally, an enlarged spleen is almost always observed, as it is over- worked destroying the abnormally elevated platelets and red blood cells. To make the diagnosis, it is imperative to obtain a detailed patient history and find out whether polycythemia vera was diagnosed in the past few decades based on the criteria defined for the disease. Treatment principles were initially directed toward palliative care, including removal of spleen, radiation and use of drugs that reduce inflammation and suppress the activity of the immune system, but because JAK2 mutations are discovered in more than 95% of patients, the group of JAK inhibitor drugs is becoming the mainstay of therapy. Despite the fact that stem cell transplantation may provide curative effects, elderly patients with multiple comorbidities may not be suitable for this procedure. The prognosis is currently not good, as median survival rates are between 5-8 years after diagnosis. Although the 10 and 15-year risk of PV progressing to myelofibrosis ranges between 5-14%, respectively, screening of all patients suffering from polycythemia vera for JAK mutations may be of significant benefit in long-term monitoring.

1. Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson J, Loscalzo J. eds. Harrison's Principles of Internal Medicine, 18e. New York, NY: McGraw-Hill; 2012.
2. Means RT. JAK2 V617F and the evolving paradigm of polycythemia vera. Korean J Hematol. 2010;45(2):90-94.
3. Tefferi A, Thiele J, Orazi A, Kvasnicka HM, Barbui T, Hanson CA, et al. Proposals and rationale for revision of the World Health Organization diagnostic criteria for polycythemia vera, essential thrombocythemia, and primary myelofibrosis: recommendations from an ad hoc international expert panel. Blood 2007;110:1092-1097.
4. James C, Ugo V, Le Couedic JP, et al. A unique clonal JAK2 mutation leading to constitutive signalling causes polycythaemia vera. Nature. 2005;434(7037):1144-1148.
5. Mehta J, Wang H, Iqbal SU, et al. Epidemiology of myeloproliferative neoplasms in the United States. Leuk Lymphoma 2014;55:595-600.
6. Passamonti F, Rumi E, Caramella M, et al. A dynamic prognostic model to predict survival in post-polycythemia vera myelofibrosis. Blood 2008;111:3383–3387.
7. Bai J, Ai L, Zhang L, et al. Incidence and risk factors for myelofibrotic transformation among 272 Chinese patients with JAK2-mutated polycythemia vera. Am J Hematol. September 2015; Sep 8.
8. Randhawa J, Ostojic A, Vrhovac R, Atallah E, Verstovsek S. Splenomegaly in myelofibrosis—new options for therapy and the therapeutic potential of Janus kinase 2 inhibitors. J Hematol Oncol. 2012;5:43.
9. Barosi G, Mesa RA, Thiele J, Cervantes F, Campbell PJ, Verstovsek S,et al. Proposed criteria for the diagnosis of post-polycythemia vera and post-essential thrombocythemia myelofibrosis: a consensus statement from the international working group for myelofibrosis research and treatment. Leukemia. 2008;22:437–438.
10. Barbui T, Barosi G, Birgegard G, et al. Philadelphia-negative classical myeloproliferative neoplasms: critical concepts and management recommendations from European LeukemiaNet. J Clin Oncol. 2011;29(6):761-770.
11. Sonbol MB, Firwana B, Zarzour A, et al. Comprehensive review of JAK inhibitors in myeloproliferative neoplasms. Ther Adv Hematol. 2013;4(1):15-35.
12. Nussenzveig RH, Swierczek SI, Jelinek J, et al. Polycythemia vera is not initiated by JAK2V617F mutation. Exp Hematol. 2007;35:32–38.
13. Moulard O, Mehta J, Fryzek J, et al. Epidemiology of myelofibrosis, essential thrombocythemia, and polycythemia vera in the European Union. Eur J Haematol 2014;92:289-297.
14. Beauverd Y, Alimam S, McLornan DP, Radia DH, Harrison CN. Disease characteristics and outcomes in younger adults with primary and secondary myelofibrosis. Br J Haematol. 2016; Jun 13.
15. Cerquozzi S, Tefferi A. Blast transformation and fibrotic progression in polycythemia vera and essential thrombocythemia: a literature review of incidence and risk factors. Blood Cancer J. 2015;5:e366.
16. Tam CS, Kantarjian H, Cortes J, et al. Dynamic model for predicting death within 12 months in patients with primary or post-polycythemia vera/essential thrombocythemia myelofibrosis. J Clin Oncol. 2009;27(33):5587–5593.