RESUMEN
BCR-ABL1-negative myeloproliferative disorders and chronic myeloid leukaemia are haematologic malignancies characterised by single and mutually exclusive genetic alterations. Nevertheless, several patients co-expressing the JAK2V617F mutation and the BCR-ABL1 transcript have been described in the literature. We report the case of a 61-year-old male who presented with an essential thrombocythaemia phenotype and had a subsequent diagnosis of chronic phase chronic myeloid leukaemia. Colony-forming assays demonstrated the coexistence of 2 different haematopoietic clones: one was positive for the JAK2V617F mutation and the other co-expressed both JAK2V617F and the BCR-ABL1 fusion gene. No colonies displayed the BCR-ABL1 transcript alone. These findings indicate that the JAK2V617F mutation was the founding genetic alteration of the disease, followed by the acquisition of the BCR-ABL1 chimeric oncogene. Our data support the hypothesis that a heterozygous JAK2V617F clone may have favoured the bi-clonal nature of this myeloproliferative disorder, generating clones harbouring a second transforming genetic event.
Asunto(s)
Proteínas de Fusión bcr-abl , Regulación Enzimológica de la Expresión Génica , Regulación Leucémica de la Expresión Génica , Janus Quinasa 2 , Leucemia Mielógena Crónica BCR-ABL Positiva , Mutación Missense , Trombocitemia Esencial , Sustitución de Aminoácidos , Ensayo de Unidades Formadoras de Colonias , Proteínas de Fusión bcr-abl/biosíntesis , Proteínas de Fusión bcr-abl/genética , Humanos , Janus Quinasa 2/biosíntesis , Janus Quinasa 2/genética , Leucemia Mielógena Crónica BCR-ABL Positiva/enzimología , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Leucemia Mielógena Crónica BCR-ABL Positiva/patología , Masculino , Persona de Mediana Edad , Trombocitemia Esencial/enzimología , Trombocitemia Esencial/genética , Trombocitemia Esencial/patologíaAsunto(s)
Janus Quinasa 2/genética , Policitemia Vera/diagnóstico , Trombocitemia Esencial/diagnóstico , Adolescente , Médula Ósea/patología , Niño , Preescolar , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Mutación Missense , Mutación Puntual , Policitemia Vera/enzimología , Policitemia Vera/genética , Policitemia Vera/patología , Trombocitemia Esencial/enzimología , Trombocitemia Esencial/genética , Trombocitemia Esencial/patologíaRESUMEN
An accurate histological diagnosis may distinguish essential thrombocythaemia (ET) from early primary myelofibrosis (early-PMF), which is associated with worse outcome. Outcome of ET is also negatively affected by the presence of the JAK2V617F mutation. To investigate the impact of JAK2V617F mutation burden and histology on outcome, we collected 475 WHO-diagnosed ET (69.2%) or early-PMF JAK2V617F -positive patients followed in 4 Italian haematology centers. JAK2V617F allele burden was ≤50% in 90% and 87% of ET and early-PMF patients, respectively (P = .34). During follow-up, 32 (9.7%) ET and 18 (12.3%) early-PMF patients experienced 59 thrombotic events, and 27 patients (5.6%) and 6 (1.2%) patients evolved to myelofibrosis and acute leukemia, respectively. At last contact, 28 (5.8%) patients had died. In early-PMF compared to ET, the 10-year mortality rates (6.7% and 4.3%, P = .73), leukemic transformation rates (1.4% and 1.2%, P = .45), and thrombosis rates (16.7% and 12.2%, P = .12) were comparable. Only progression to overt myelofibrosis at 10 years was significantly worse (11.4% and 1.5%, P = .004). In multivariate analysis, a higher (>50%) JAK2V617F burden was significantly correlated with fibrotic progression and histology. Considering JAK2V617F -positive disease, a higher (>50%) JAK2V617F burden and histological classification are independent prognostic risk factors for disease progression. These findings reinforce the need for standardized detection of this mutation.
Asunto(s)
Janus Quinasa 2/genética , Mielofibrosis Primaria/enzimología , Trombocitemia Esencial/enzimología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Estudios de Cohortes , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mutación , Mielofibrosis Primaria/genética , Mielofibrosis Primaria/mortalidad , Mielofibrosis Primaria/patología , Análisis de Supervivencia , Trombocitemia Esencial/genética , Trombocitemia Esencial/mortalidad , Trombocitemia Esencial/patología , Resultado del Tratamiento , Adulto JovenRESUMEN
Since its approval in 2011, the Janus kinase 1/2 (JAK1/2) inhibitor ruxolitinib has evolved to become the centerpiece of therapy for myelofibrosis (MF), and its use in patients with hydroxyurea resistant or intolerant polycythemia vera (PV) is steadily increasing. Several other JAK2 inhibitors have entered clinical testing, but none have been approved and many have been discontinued. Importantly, the activity of these agents is not restricted to patients with JAK2 V617F or exon 12 mutations. Although JAK2 inhibitors provide substantial clinical benefit, their disease-modifying activity is limited, and rational combinations with other targeted agents are needed, particularly in MF, in which survival is short. Many such combinations are being explored, as are other novel agents, some of which could successfully be combined with JAK2 inhibitors in the future. In addition, new JAK2 inhibitors with the potential for less myelosuppression continue to be investigated. Given the proven safety and efficacy of ruxolitinib, it is likely that ruxolitinib-based combinations will be a major way forward in drug development for MF. If approved, less myelosuppressive JAK2 inhibitors such as pacritinib or NS-018 could prove to be very useful additions to the therapeutic armamentarium in MF. In PV, inhibitors of histone deacetylases and human double minute 2 have activity, but their role, if any, in the future treatment algorithm is uncertain, given the availability of ruxolitinib and renewed interest in interferons. Ruxolitinib is in late-phase clinical trials in essential thrombocythemia, in which it could fill an important void for patients with troublesome symptoms.
Asunto(s)
Antineoplásicos/uso terapéutico , Janus Quinasa 2/antagonistas & inhibidores , Policitemia Vera/tratamiento farmacológico , Mielofibrosis Primaria/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/uso terapéutico , Pirazoles/uso terapéutico , Trombocitemia Esencial/tratamiento farmacológico , Hidrocarburos Aromáticos con Puentes/uso terapéutico , Expresión Génica , Humanos , Janus Quinasa 1/antagonistas & inhibidores , Janus Quinasa 1/genética , Janus Quinasa 1/metabolismo , Janus Quinasa 2/genética , Janus Quinasa 2/metabolismo , Mutación , Nitrilos , Seguridad del Paciente , Policitemia Vera/enzimología , Policitemia Vera/genética , Policitemia Vera/patología , Mielofibrosis Primaria/enzimología , Mielofibrosis Primaria/genética , Mielofibrosis Primaria/patología , Pirimidinas/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto , Trombocitemia Esencial/enzimología , Trombocitemia Esencial/genética , Trombocitemia Esencial/patología , Resultado del TratamientoRESUMEN
The 2016 World Health Organization (WHO) diagnostic criteria for myeloproliferative neoplasms (MPN) underscore the prognostically-relevant distinction between essential thrombocythemia (ET) and prefibrotic primary myelofibrosis (pre-PMF). In addition, leukocytosis has been identified as an important prognostic marker in otherwise WHO-defined ET. However, controversy remains regarding the objectivity of morphologic criteria in distinguishing ET from pre-PMF and the precise prognostic cutoff values for leukocytosis. Serum lactate dehydrogenase (LDH) level might be a biologically more accurate measure of leukocyte turnover and a more sensitive marker of pre-PMF, in otherwise WHO-defined ET. In the current study of 183 consecutive patients with WHO-defined ET, the presence of grade 1 bone marrow (BM) fibrosis did not affect presenting clinical or laboratory features; in contrast, increased serum LDH at diagnosis was associated with leukocytosis (p = .002), thrombocytosis (p < .001), palpable splenomegaly (p = .03) and higher international prognostic score (IPSET) (p = .002); serum LDH did not correlate with BM fibrosis, JAK2/CALR/MPL or TET2/ASXL1 mutations. In univariate analysis, risk factors for survival included age ≥60 years (p = .002; HR 10.2, 95% CI 2.3-44.6), male sex (p = .02; HR 3.2, 95% CI 1.2-8.2), leukocyte count ≥15 × 109 /L (p = .007; HR 4.7, 95% CI 1.5-14.6), and increased serum LDH (p = .002; HR 3.7, 95% CI 1.5-9.1), but not BM fibrosis (p = .17). In multivariable analysis, age, sex and serum LDH remained significant; serum LDH also remained significant, in the context of IPSET (p = .003) and in patients with leukocytosis (p = .003). We conclude that serum LDH level carries an independent prognostic value for survival in ET and might represent a biologically more accurate surrogate for leukocytosis.
Asunto(s)
Lactato Deshidrogenasas/sangre , Mielofibrosis Primaria/patología , Trombocitemia Esencial/patología , Anciano , Anciano de 80 o más Años , Biomarcadores , Femenino , Humanos , Leucocitosis/enzimología , Masculino , Persona de Mediana Edad , Pronóstico , Reticulina , Factores de Riesgo , Trombocitemia Esencial/enzimologíaRESUMEN
Essential thrombocythaemia (ET) is one of the severe rare clonal haematologic stem cell disorders that encompass myeloproliferative neoplasms. ET has a well-described association with peripheral arterial thrombosis, which presents a challenging clinical presentation. Further understanding into the underlying pathophysiology of thrombosis in ET has been made following the identification of the Janus Kinase 2 (JAK2) mutation, which is thought to confer a prothrombotic phenotype. Here we present a case of refractory arterial insufficiency associated with JAK2-positive ET.
Asunto(s)
Arteriopatías Oclusivas/genética , Janus Quinasa 2/genética , Mutación , Trombocitemia Esencial/genética , Amputación Quirúrgica , Angioplastia de Balón , Antibacterianos/uso terapéutico , Arteriopatías Oclusivas/diagnóstico , Arteriopatías Oclusivas/enzimología , Arteriopatías Oclusivas/terapia , Angiografía por Tomografía Computarizada , Análisis Mutacional de ADN , Desbridamiento , Femenino , Predisposición Genética a la Enfermedad , Humanos , Hidroxiurea/uso terapéutico , Persona de Mediana Edad , Fenotipo , Inhibidores de Agregación Plaquetaria/uso terapéutico , Recuento de Plaquetas , Trombocitemia Esencial/diagnóstico , Trombocitemia Esencial/tratamiento farmacológico , Trombocitemia Esencial/enzimología , Resultado del Tratamiento , Cicatrización de HeridasRESUMEN
Pharmacological inhibition of the kinase activity of JAK proteins can interfere with the signaling of immunomodulatory cytokines and block the constitutive activation of the JAK-STAT pathway that characterizes certain malignancies, including chronic myeloproliferative neoplasms. JAK inhibitors may, therefore, be useful to treat malignancies as well as inflammatory or immune disorders. Currently, the most significant advances have been made in the treatment of myelofibrosis, where these drugs may lead to a remarkable improvement in the control of hyperproliferative manifestations. However, available data suggest that this treatment is not curative of myelofibrosis. In general, JAK2 inhibition induces cytopaenias, with this being considered a class side-effect. By contrast, the extrahaematologic toxicity profile varies significantly among the different JAK inhibitors. At present, there are several clinical trials evaluating the combination of ruxolitinib with other drugs, in order to improve its therapeutic activity as well as reducing haematologic toxicity.
Asunto(s)
Janus Quinasa 2/antagonistas & inhibidores , Policitemia Vera/tratamiento farmacológico , Mielofibrosis Primaria/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/uso terapéutico , Trombocitemia Esencial/tratamiento farmacológico , Enfermedades Autoinmunes/tratamiento farmacológico , Enfermedades Autoinmunes/enzimología , Humanos , Nitrilos , Policitemia Vera/enzimología , Mielofibrosis Primaria/enzimología , Pirazoles/uso terapéutico , Pirimidinas , Trombocitemia Esencial/enzimología , Resultado del TratamientoRESUMEN
Patients with polycythaemia vera (PV), essential thrombocythaemia (ET) and primary myelofibrosis (PMF) are at increased risk of arterial and venous thrombosis. In patients with ET a positive correlation was observed between JAK-2 V617F mutation, that facilitates erythropoietin receptor signalling, and thrombotic events, although the mechanism involved is not clear. We previously demonstrated that heparanase protein forms a complex and enhances the activity of the blood coagulation initiator tissue factor (TF) which leads to increased factor Xa production and subsequent activation of the coagulation system. The present study was aimed to evaluate heparanase procoagulant activity in myeloproliferative neoplasms. Forty bone marrow biopsies of patients with ET, PV, PMF and chronic myelogenous leukaemia (CML) were immunostained to heparanase, TF and TF pathway inhibitor (TFPI). Erythropoietin receptor positive cell lines U87 human glioma and MCF-7 human breast carcinoma were studied. Heparanase and TFPI staining were more prominent in ET, PV and PMF compared to CML. The strongest staining was in JAK-2 positive ET biopsies. Heparanase level and procoagulant activity were higher in U87 cells transfected to over express JAK-2 V617F mutation compared to control and the effect was reversed using JAK-2 inhibitors (Ruxolitinib, VZ3) and hydroxyurea, although the latter drug did not inhibit JAK-2 phosphorylation. Erythropoietin increased while JAK-2 inhibitors decreased the heparanase level and procoagulant activity in U87 and MCF-7 parental cells. In conclusion, JAK-2 is involved in heparanase up-regulation via the erythropoietin receptor. The present findings may potentially point to a new mechanism of thrombosis in JAK-2 positive ET patients.
Asunto(s)
Médula Ósea/enzimología , Glucuronidasa/metabolismo , Janus Quinasa 2/genética , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Mutación , Policitemia Vera/genética , Mielofibrosis Primaria/genética , Trombocitemia Esencial/genética , Biopsia , Médula Ósea/efectos de los fármacos , Examen de la Médula Ósea , Análisis Mutacional de ADN , Marcadores Genéticos , Predisposición Genética a la Enfermedad , Humanos , Janus Quinasa 2/antagonistas & inhibidores , Janus Quinasa 2/metabolismo , Leucemia Mielógena Crónica BCR-ABL Positiva/sangre , Leucemia Mielógena Crónica BCR-ABL Positiva/enzimología , Lipoproteínas/metabolismo , Células MCF-7 , Fenotipo , Fosforilación , Policitemia Vera/sangre , Policitemia Vera/enzimología , Mielofibrosis Primaria/sangre , Mielofibrosis Primaria/enzimología , Inhibidores de Proteínas Quinasas/farmacología , Receptores de Eritropoyetina/metabolismo , Trombocitemia Esencial/sangre , Trombocitemia Esencial/enzimología , TransfecciónAsunto(s)
Trombosis Coronaria/etiología , ADN/genética , Janus Quinasa 2/genética , Mutación , Trombocitemia Esencial/genética , Adulto , Trombosis Coronaria/enzimología , Trombosis Coronaria/genética , Análisis Mutacional de ADN , Humanos , Janus Quinasa 2/metabolismo , Masculino , Recurrencia , Trombocitemia Esencial/complicaciones , Trombocitemia Esencial/enzimologíaAsunto(s)
Alopecia/tratamiento farmacológico , Pirazoles/uso terapéutico , Trombocitemia Esencial/tratamiento farmacológico , Adulto , Alopecia/complicaciones , Alopecia/enzimología , Alopecia/inmunología , Femenino , Humanos , Quinasas Janus/antagonistas & inhibidores , Quinasas Janus/genética , Nitrilos , Pirazoles/administración & dosificación , Pirimidinas , Trombocitemia Esencial/sangre , Trombocitemia Esencial/complicaciones , Trombocitemia Esencial/enzimología , Resultado del Tratamiento , Adulto JovenRESUMEN
JAK2-V617F is central to the pathogenesis of myeloproliferative neoplasms. We examined whether lestaurtinib decreased JAK2-V617F allele burden and evaluated its clinical benefits and tolerability in patients with polycythaemia vera (PV) and essential thrombocythaemia (ET). This phase 2, open-label, multicentre study was designed to detect ≥15% reduction in JAK2-V617F allele burden in 15% of patients. Eligible patients received lestaurtinib 80 mg twice daily for 18 weeks and could participate in a 1-year extension phase of treatment. Of 39 enrolled patients, 27 (69%) had PV; 12 (31%) had ET. While the pre-specified responder rate of 15% was not met, lestaurtinib modestly reduced JAK2-V617F allele burden and reduced spleen size in a subset of patients. Of 37 patients in the full efficacy analysis, 5 (14%) responded clinically. Every patient had ≥1 adverse event, most commonly gastrointestinal (95%). Fifteen patients (38%) experienced serious adverse events; 23 (59%) withdrew due to adverse events. This is the first reported study of JAK2-inhibitor treatment in patients with PV/ET and highlights both the need for further studies to assess the role of JAK2 inhibition in treatment of PV/ET and the use of JAK2-V617F as a biomarker for response. This trial was registered at www.clinicaltrials.gov as NCT00586651.
Asunto(s)
Carbazoles/uso terapéutico , Janus Quinasa 2/genética , Mutación , Policitemia Vera/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/uso terapéutico , Trombocitemia Esencial/tratamiento farmacológico , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Furanos , Humanos , Masculino , Persona de Mediana Edad , Policitemia Vera/enzimología , Policitemia Vera/genética , Policitemia Vera/patología , Trombocitemia Esencial/enzimología , Trombocitemia Esencial/genética , Trombocitemia Esencial/patología , Resultado del TratamientoRESUMEN
Thrombotic complications are a major cause of death in patients with Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs), which are closely associated with the JAK2 V617F activating mutation. However, whether the presence of the JAK2 V617F mutation affects thrombotic risk is currently unknown, although some reports have suggested a variable association with thrombosis. Therefore, we investigated the association between JAK2 V617F and various complications, including thrombosis, in Japanese patients with MPNs. We assessed the JAK2 V617F status in 140 patients who were diagnosed or doubted as having some type of MPN by utilizing a JAK2 V617F-specific guanine-quenching probe. JAK2 V617F was detected in 31 of 51 patients (60.8%) with essential thrombocythemia, all 16 patients (100%) with polycythemia vera, 4 of 11 patients (36.4%) with primary myelofibrosis, 2 of 18 patients (11.1%) with other types of MPNs, and none of the 44 patients with doubted MPN. In the 78 patients with classical MPN, JAK2 V617F correlated with a leukocyte count ≥10,000/µl (p=0.046). Complications of thrombosis, hemorrhage, and leukemic transformation occurred in 21 (41.2%), 4 (25.0%), and 3 (27.3%) patients with classical MPN, respectively, and thrombotic events (TE) occurred more frequently in patients with JAK2 V617F than without (p=0.047). Based on these findings, initial screening for the JAK2 mutation and careful monitoring for thrombotic events should be performed in patients with MPN.
Asunto(s)
Janus Quinasa 2/genética , Mutación , Trastornos Mieloproliferativos/genética , Tromboembolia/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Análisis Mutacional de ADN , Femenino , Predisposición Genética a la Enfermedad , Pruebas Genéticas/métodos , Humanos , Incidencia , Japón/epidemiología , Recuento de Leucocitos , Masculino , Persona de Mediana Edad , Trastornos Mieloproliferativos/sangre , Trastornos Mieloproliferativos/complicaciones , Trastornos Mieloproliferativos/enzimología , Trastornos Mieloproliferativos/epidemiología , Policitemia Vera/enzimología , Policitemia Vera/genética , Valor Predictivo de las Pruebas , Mielofibrosis Primaria/enzimología , Mielofibrosis Primaria/genética , Estudios Retrospectivos , Factores de Riesgo , Trombocitemia Esencial/enzimología , Trombocitemia Esencial/genética , Tromboembolia/sangre , Tromboembolia/enzimología , Tromboembolia/epidemiología , Adulto JovenRESUMEN
In patients not meeting the required hematocrit (HCT) or hemoglobin (Hb) thresholds according to BCSH and the WHO diagnostic criteria, the diagnosis of masked polycythemia vera (mPV) has been proposed. A comparison of HCT or Hb values with the expression of JAK2V617F, JAK2 exon 12, and CALR mutations in strictly WHO-defined 257 overt PV and 140 mPV (59 mPV according to BCSH) and 397 patients with essential thrombocythemia (ET) was performed. Hb and HCT thresholds of mPV patients were significantly higher than JAK2V617F ET (P < 0.0001). The best cut-off for Hb to discriminate JAK2-mutated ET from PV was 16.5 g/dL for males and 16.0 g/dL for females. For HCT, this was 49% in males and 48% in females. The proportion of patients correctly classified as ET or PV when regarding Hb or HCT levels was 95% in males and 93% in females and 94% in both males and females, respectively.
Asunto(s)
Janus Quinasa 2/genética , Mutación , Policitemia Vera/diagnóstico , Trombocitemia Esencial/diagnóstico , Diagnóstico Diferencial , Femenino , Hematócrito , Hemoglobinas/genética , Hemoglobinas/metabolismo , Humanos , Masculino , Policitemia Vera/sangre , Policitemia Vera/enzimología , Policitemia Vera/genética , Factores Sexuales , Trombocitemia Esencial/sangre , Trombocitemia Esencial/enzimología , Trombocitemia Esencial/genéticaRESUMEN
The JAK2V617F allele burden has been identified as a risk factor for vascular events and myelofibrotic transformation in polycythemia vera (PV) and essential thrombocythemia (ET). However, all previous studies have evaluated a single time point JAK2V617F measurement. Therefore, the frequency and the clinical significance of changes in the JAK2V617F mutant load occurring during the disease evolution remain unknown. In the present study, JAK2V617F monitoring was performed during the follow-up of 347 patients (PV = 163, ET = 184). According to their JAK2V617F evolutionary patterns, patients were stratified as stable < 50% (n = 261), stable ≥50% (n = 52), progressive increase (n = 24) and unexplained decrease (n = 10). After a 2,453 person-years follow-up, a total of 59 thrombotic events, 16 major hemorrhages, and 27 cases of myelofibrotic transformations were registered. At multivariate analyses, patients with a persistently high (≥50%) or unsteady JAK2V617F load during follow-up had an increased risk of myelofibrotic transformation (Incidence rate ratio [IRR]: 20.7, 95% CI: 6.5-65.4; P < 0.001) and a trend for a higher incidence of thrombosis (IRR: 1.7, 1-3.3; P = 0.05) than patients with a stable allele burden below 50%. In conclusion, JAK2V617F monitoring could be useful in patients with PV and ET for predicting disease's complications, especially myelofibrotic transformation.
Asunto(s)
Janus Quinasa 2/sangre , Janus Quinasa 2/genética , Policitemia Vera/enzimología , Mielofibrosis Primaria/enzimología , Trombocitemia Esencial/enzimología , Trombosis/enzimología , Adulto , Anciano , Anciano de 80 o más Años , Alelos , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Policitemia Vera/sangre , Policitemia Vera/genética , Mielofibrosis Primaria/sangre , Mielofibrosis Primaria/genética , Análisis de Supervivencia , Trombocitemia Esencial/sangre , Trombocitemia Esencial/genética , Trombosis/sangre , Trombosis/genética , Adulto JovenRESUMEN
INTRODUCTION: We performed a comparative analysis of telomerase activity (TA) in patients with myeloproliferative neoplasm (MPN) and myelodysplastic syndrome (MDS). The relationships between TA and known prognostic factors were also analyzed. MATERIALS AND METHODS: A telomeric repeat amplification protocol was performed with bone marrow hematopoietic cells from 96 normal controls, 44 MPNs, and 40 MDSs. RESULT: TA (measured as molecules/reaction) showed no correlation with age in the control group (R(2)=0.0057, p=0.464). MPN showed elevated TA compared with controls (15,537.57 vs. 7775.44, p=0.020). Patients with essential thrombocythemia showed markedly elevated TA (22,688.56, p=0.030), particularly in cases with extreme thrombocytosis versus those without extreme thrombocytosis (34,522.19 vs. 9375.71, p=0.041). MDS patients showed a TA value of 7578.50. CONCLUSION: There was no association between age and TA in bone marrow hematopoietic cells. TA was elevated in MPN but borderline in MDS, probably because of differences in the nature of the diseases. Elevated TA in patients with essential thrombocythemia, especially those with extreme thrombocytosis, suggests that an anti-telomerase strategy could be beneficial in the prevention of thrombotic complications.
Asunto(s)
Telomerasa/metabolismo , Trombocitemia Esencial/complicaciones , Trombocitemia Esencial/enzimología , Trombocitosis/complicaciones , Trombocitosis/enzimología , Adulto , Anciano , Envejecimiento/metabolismo , Estudios de Casos y Controles , Humanos , Persona de Mediana Edad , Síndromes Mielodisplásicos/complicaciones , Síndromes Mielodisplásicos/enzimología , Factores de Riesgo , Adulto JovenRESUMEN
The principal morbidity and mortality in patients with essential thrombocythemia (ET) and polycythemia rubra vera (PV) stems from thrombotic events. Most patients with ET/PV harbor a JAK2V617F mutation, but its role in the thrombotic diathesis remains obscure. Platelet function studies in patients are difficult to interpret because of interindividual heterogeneity, reflecting variations in the proportion of platelets derived from the malignant clone, differences in the presence of additional mutations, and the effects of medical treatments. To circumvent these issues, we have studied a JAK2V617F knock-in mouse model of ET in which all megakaryocytes and platelets express JAK2V617F at a physiological level, equivalent to that present in human ET patients. We show that, in addition to increased differentiation, JAK2V617F-positive megakaryocytes display greater migratory ability and proplatelet formation. We demonstrate in a range of assays that platelet reactivity to agonists is enhanced, with a concomitant increase in platelet aggregation in vitro and a reduced duration of bleeding in vivo. These data suggest that JAK2V617F leads to intrinsic changes in both megakaryocyte and platelet biology beyond an increase in cell number. In support of this hypothesis, we identify multiple differentially expressed genes in JAK2V617F megakaryocytes that may underlie the observed biological differences.
Asunto(s)
Plaquetas/enzimología , Janus Quinasa 2/sangre , Janus Quinasa 2/genética , Proteínas Mutantes/sangre , Proteínas Mutantes/genética , Mutación , Trombocitemia Esencial/sangre , Trombocitemia Esencial/genética , Animales , Plaquetas/patología , Modelos Animales de Enfermedad , Expresión Génica , Humanos , Megacariocitos/enzimología , Megacariocitos/patología , Ratones , Ratones Transgénicos , Agregación Plaquetaria/genética , Proteínas Recombinantes/sangre , Proteínas Recombinantes/genética , Trombocitemia Esencial/enzimología , Trombopoyesis/genéticaRESUMEN
Detection of the JAK2 p.V617F mutation and measurement of its allele burden can be performed using both peripheral blood (PB) and bone marrow (BM) samples from patients with myeloproliferative neoplasms (MPNs). However, the diagnostic accuracy of detecting the JAK2 p.V617F mutation and quantifying its allele burden in PB and BM samples has not been systematically compared. We retrospectively analyzed 388 patients with MPN who had been tested for JAK2 p.V617F allele burden using both PB and BM samples within 3 months of each other. The sensitivity and specificity of detecting JAK2 p.V617F in PB when compared with BM were both 100%. Furthermore, the JAK2 p.V617F allele burden measured in PB and BM were equivalent by linear regression analysis (R(2) = 0.991; P < .0001). We therefore conclude that PB is a reliable source for testing for the JAK2 p.V617F mutation and quantifying its allele burden in patients with MPN.
Asunto(s)
Janus Quinasa 2/sangre , Janus Quinasa 2/genética , Proteínas Mutantes/sangre , Proteínas Mutantes/genética , Mutación , Trastornos Mieloproliferativos/enzimología , Trastornos Mieloproliferativos/genética , Alelos , Sustitución de Aminoácidos , Médula Ósea/metabolismo , Humanos , Janus Quinasa 2/metabolismo , Modelos Lineales , Proteínas Mutantes/metabolismo , Trastornos Mieloproliferativos/sangre , Policitemia Vera/sangre , Policitemia Vera/enzimología , Policitemia Vera/genética , Mielofibrosis Primaria/sangre , Mielofibrosis Primaria/enzimología , Mielofibrosis Primaria/genética , Reproducibilidad de los Resultados , Estudios Retrospectivos , Trombocitemia Esencial/sangre , Trombocitemia Esencial/enzimología , Trombocitemia Esencial/genéticaRESUMEN
Dysregulated expression of signaling proteins may contribute to the pathophysiology of essential thrombocythemia (ET). This study aimed to characterize protein expression in ET and to correlate the dysregulated proteins with phenotypes and prognosis of ET patients. The expression of 128 proteins in peripheral blood neutrophils from 74 ET patients was assessed and compared with those from 29 healthy subjects and 35 polycythemia vera (PV) patients using protein pathway array. Fifteen proteins were differentially expressed between ET patients and normal controls. These dysregulated proteins were involved in the signaling pathways related with apoptosis and inflammation. Our results showed a significant overlap in protein expression between ET patients with JAK2V617F mutation and PV patients. In addition, nine proteins were associated with JAK2V617F mutation status in ET patients. Furthermore, estrogen receptor beta (ERß) and Stat3 were independent risk factors for subsequent thrombosis during follow-up on multivariable analysis. Our study shows a broad dysregulation of signaling protein in ET patients, suggesting their roles in ET pathogenesis. The expression levels of ERß and Stat3 could be promising predictors of subsequent thrombosis in ET patients.
Asunto(s)
Receptor beta de Estrógeno/genética , Regulación de la Expresión Génica , Péptidos y Proteínas de Señalización Intracelular/genética , Janus Quinasa 2/genética , Mutación/genética , Factor de Transcripción STAT3/genética , Trombocitemia Esencial/genética , Adulto , Anciano , Anciano de 80 o más Años , Receptor beta de Estrógeno/biosíntesis , Femenino , Estudios de Seguimiento , Pruebas Genéticas , Humanos , Péptidos y Proteínas de Señalización Intracelular/biosíntesis , Janus Quinasa 2/biosíntesis , Masculino , Persona de Mediana Edad , Policitemia Vera/enzimología , Policitemia Vera/genética , Policitemia Vera/metabolismo , Factores de Riesgo , Factor de Transcripción STAT3/biosíntesis , Trombocitemia Esencial/enzimología , Trombocitemia Esencial/metabolismo , Trombosis/genética , Trombosis/metabolismo , Adulto JovenRESUMEN
This study aimed to assess the antitumour effects, molecular mechanisms of action, and potential synergy of ruxolitinib with sorafenib, KNK437, dasatinib, and perifosine, in Philadelphia-negative chronic myeloproliferative neoplasms (MPN). Cytotoxic and cytostatic effects of the different compounds were determined in the JAK2 V617F-positive cell lines, HEL and Ba/F3 (JAK2V617F EPOR) , and in primary mononuclear and bone marrow CD34-positive cells from 19 MPN patients. Ruxolitinib [50% inhibitory concentration (IC50 )(PV) = 15 nmol/l], as well as sorafenib (IC50 PV=8µmol/l), KNK437 (IC50 PV=100µmol/l ), and perifosine (IC50 PV=15µmol/l ), were able to inhibit proliferation in cell line models and in primary cells from MPN patients. Dasatinib, KNK437, and sorafenib showed a strong synergistic effect in combination with ruxolitinib [combination index (CI)(PV) < 0·3]. Western blot confirmed that ruxolitinib blocked ERK, and consequently STAT5 activation, sorafenib inhibited ERK, P38 and STAT5, dasatinib blocked SRC and STAT5, and KNK437 decreased the stability of the JAK2 protein, reducing its expression. Inhibiting JAK2-related proliferative pathways has the potential to inhibit cell proliferation in MPNs. Furthermore, the combination of ruxolitinib with inhibitors that target these pathways has a strong synergistic effect, which may be due to decreased activation of the common effector, STAT5.