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Query: EC:2.7.10.2 (
focal adhesion kinase
)
44,029
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Acute megakaryoblastic leukaemia (AML-M7) is an uncommon disease, composing 0.5-1.2% of newly diagnosed adult acute myeloid leukaemias (AML). It is characterised by higher incidence and complexity of cytogenetic abnormalities. We report a rare case of Philadelphia (Ph) chromosome-positive AML-M7, presenting with extreme
thrombocytosis
and having a poor outcome. The diagnosis was established on the basis of morphological and flow cytometry data for megakaryoblastic proliferation in the bone marrow. Cytogenetics revealed 47,XX,+8,t(9;22)(q34;q11), and p190(BCR-
ABL
)-rearrangement was detected. MDR1-gene overexpression was not demonstrated; however, the patient was resistant to therapy and died in 6 months. The reported case contributes to the overt heterogeneity of Ph-positive AMLs, which warrants further investigation and understanding.
...
PMID:Acute megakaryoblastic leukaemia with extreme thrombocytosis and p190(bcr/abl)rearrangement. 1461 10
Chronic myeloproliferative disorders (CMPD) are neoplastic disorders of the hematopoietic stem cell. Four different entities are defined: chronic myeloid leukemia (CML), polycythemia vers, essential
thrombocythaemia
, and idiopathic myelofibrosis. In addition, overlapping entities within the CMPDs and between CMPDs and myelodysplastic syndrome have been described. Diagnostic measures are performed to classify the subtype exactly and to assess risk factors and prognosis. Cytogenetic and molecular analyses are mandatory for the characterization of the malignant clone. Hydroxyurea and interferon-alpha have proven effective in all CMPE. In CML, specific inhibition of the elevated
ABL
tyrosine kinase activity with imatinib is associated with high response rates. Allogeneic stem cell transplantation is the only curative treatment option for all entities. In CML, the decision-making analysis should be based on established scores. In BCR-
ABL
negative CMPDs an allogeneic stem cell transplantation should only be performed in patients with unfavorable prognosis.
...
PMID:[Chronic myeloproliferative diseases. Diagnosis and therapy]. 1467 16
Myeloproliferative disorders are clonal haematopoietic stem cell malignancies characterized by independency or hypersensitivity of haematopoietic progenitors to numerous cytokines. The molecular basis of most myeloproliferative disorders is unknown. On the basis of the model of chronic myeloid leukaemia, it is expected that a constitutive tyrosine kinase activity could be at the origin of these diseases. Polycythaemia vera is an acquired myeloproliferative disorder, characterized by the presence of polycythaemia diversely associated with
thrombocytosis
, leukocytosis and splenomegaly. Polycythaemia vera progenitors are hypersensitive to erythropoietin and other cytokines. Here, we describe a clonal and recurrent mutation in the JH2 pseudo-kinase domain of the
Janus kinase 2
(
JAK2
) gene in most (> 80%) polycythaemia vera patients. The mutation, a valine-to-phenylalanine substitution at amino acid position 617, leads to constitutive tyrosine phosphorylation activity that promotes cytokine hypersensitivity and induces erythrocytosis in a mouse model. As this mutation is also found in other myeloproliferative disorders, this unique mutation will permit a new molecular classification of these disorders and novel therapeutical approaches.
...
PMID:A unique clonal JAK2 mutation leading to constitutive signalling causes polycythaemia vera. 1579 61
Essential thrombocythaemia was first described over 70 years ago. This condition is dominated by thrombotic and haemorrhagic complications and, in the long-term, by risk of transformation to myelofibrosis and/or acute leukaemia. However, it is heterogeneous both clinically and biologically. Here, a review of current concepts in disease aetiology and management is offered with reference to recent focused reviews where appropriate. In addition, five specific areas are discussed in detail: the role of the trephine biopsy, the disease entity prefibrotic myelofibrosis; the recently described
Janus kinase 2
(
JAK2
) mutations; the leukaemogenicity of hydroxyurea (hydroxycarbamide); and lastly, the implications of the results of the Medical Research Council Primary
Thrombocythaemia
1 study are explored.
...
PMID:Essential thrombocythaemia: challenges and evidence-based management. 1602 44
Philadelphia-chromosome positive
thrombocythemia
without features of chronic myeloid leukemia in peripheral blood has been described in adults. It is rare in children. We present a case of Philadelphia positive
thrombocythemia
in a child who was managed with a combination of imatinib and hydroxyurea. Although a reduction in the BCR-
ABL
transcript was documented, the
thrombocytosis
was refractory to imatinib alone and required the addition of hydroxyurea.
...
PMID:Philadelphia-chromosome positive thrombocythemia in a child. 1610 85
Essential thrombocythemia, polycythemia vera, and myelofibrosis with myeloid metaplasia constitute the "classic" bcr/abl-negative myeloproliferative disorders (MPDs). Each of these MPDs represents a stem cell-derived clonal myeloproliferation with the respective features of
thrombocytosis
, erythrocytosis, and bone marrow fibrosis. Unlike with cases of chronic myeloid leukemia, in which the bcr/abl mutation is invariably detected, current diagnosis of essential thrombocythemia, polycythemia vera, and myelofibrosis with myeloid metaplasia is based on a consensus-driven set of clinical and laboratory criteria that have undergone substantial modification in recent times. The recent discovery of a recurrent activating Janus tyrosine kinase (
JAK2
) mutation (JAK2VG17F) in all 3 classic MPDs offers another opportunity for refining current diagnoses and disease classifications. In this article, we outline contemporary diagnostic algorithms for each of these disorders and provide an evidence-based approach to management.
...
PMID:bcr/abl-negative, classic myeloproliferative disorders: diagnosis and treatment. 1617 3
The combined use of bone marrow histopathology, biomarkers and clinical features has the potential to diagnose, stage and distinguish early and overt stages of ET, PV and idiopathic myelofibrosis, that has an important impact on prognosis and treatment of MPD patients. As the extension of the PVSG and WHO for ET, PV and agnogenic myeloid metaplasia (AMM), a new set of European clinical and pathological (ECP) criteria clearly distinct true ET from early or latent PV mimicking true ET, overt and advanced polycythemia vera (PV), and from
thrombocythemia
associated with prefibotic, early fibrotic stages of chronic megakaryocytic granulocytic metaplasia (CMGM) or chronic idiopathic myelofibrosis (CIMF). Cases of atypical MPD and masked PV are usually overlooked by clinicians and pathologists. Bone marrow biopsy will not differentiate between post-PV myelofibrosis versus so-called classical agnogenic myeloid metaplasia. The recent discovery of the
JAK2
V617F mutation can readily explain the trilinear megakaryocytic, erythroid and granulocytic proliferation in the bone marrow, but also the etiology of the platelet-mediated microvascular thrombotic complications at increased platelet counts and red cell mass in essential thrombocythemia and polycythemia vera.
...
PMID:Clinical, pathological and molecular features of the chronic myeloproliferative disorders: MPD 2005 and beyond. 1618 76
Polycythaemia vera (PV) is closely associated with both an acquired activating mutation of the
JAK2
tyrosine kinase (
JAK2
(V617F)) in granulocyte-derived DNA and increased granulocyte polycythaemia rubra vera-1 (PRV-1) expression. In order to explore the correlation between these two biological markers and compare their diagnostic utility, mutation analysis for
JAK2
(V617F) and quantitative measurement of granulocyte PRV-1 expression were performed on the same study sample from 100 participants: 38 with PV, 22 with essential
thrombocythaemia
(ET), 10 with agnogenic myeloid metaplasia (AMM), 19 with secondary polycythaemia (SP) and 11 healthy volunteers. The respective overall (homozygous)
JAK2
(V617F) mutational frequencies were 95% (26%), 55% (0%), 30% (0%), 0% and 0%. The corresponding figures for increased PRV-1 expression were 89%, 18%, 20%, 21% and 9%. In patients with either ET or AMM, the likelihood of detecting
JAK2
(V617F) was significantly higher in the presence of an increased PRV-1 expression (83% vs. 38%; P = 0.05). Similarly, in patients with PV, homozygous as compared with heterozygous
JAK2
(V617F) correlated with higher levels of PRV-1 expression (P = 0.11). The present study suggests an allele dose-dependent effect of
JAK2
(V617F) on granulocyte PRV-1 expression. However, compared with the PRV-1 assay, mutation screening for
JAK2
(V617F) displayed greater accuracy in distinguishing PV from SP.
...
PMID:Concomitant neutrophil JAK2 mutation screening and PRV-1 expression analysis in myeloproliferative disorders and secondary polycythaemia. 1644 42
Clinical correlates and long-term prognostic relevance of the
JAK2
(V617F) mutation was studied in 150 patients with essential
thrombocythaemia
(ET) from a single institution and followed for a median of 11.4 years. During this period, thrombotic complications were documented in 62 patients (41.3%) and transformation into acute myeloid leukaemia (AML), polycythaemia vera (PV), or myelofibrosis with myeloid metaplasia (MMM) occurred in 4 (2.7%), 8 (5.3%), and 15 (10%) patients, respectively.
JAK2
(V617F) was detected in either archived bone marrow or blood cells from 73 patients (48.7%) but none were homozygous for the mutant allele. Parameters at diagnosis that were significantly associated with the presence of
JAK2
(V617F) included advanced age and higher counts of both haemoglobin and leucocytes. During follow-up, patients with the mutation were more likely to transform into PV but the incidences of AML, MMM, or thrombotic events were similar between patients with and without the mutation. Multivariate analysis identified advanced age, higher haemoglobin level, and thrombosis history but not the presence of
JAK2
(V617F) as independent predictors of inferior survival. Therefore, although the presence of
JAK2
(V617F) in ET appears to promote a PV phenotype, it might not carry treatment-relevant information.
...
PMID:JAK2 mutation in essential thrombocythaemia: clinical associations and long-term prognostic relevance. 1619 51
Polycythemia vera (PV) is a clonal disorder of unknown etiology involving a multipotent hematopoietic progenitor cell that is characterized by the accumulation of phenotypically normal red blood cells, white blood cells, and platelets in the absence of a definable cause; extramedullary hematopoiesis, marrow fibrosis, and, in a few patients, transformation to acute leukemia can also occur. First described in 1892, the cause of the disease remains unknown and no potentially curative therapy other than bone marrow transplantation is currently available. It is commonly held that PV is a rare disorder, when in fact with a minimum incidence of 2.6 per 100,000 it is more common than chronic myelogenous leukemia (CML) and is particularly prevalent in persons of Ashkenazi Jewish ancestry. However, the incidence of PV is not as high as that of erythrocytosis from other causes collectively, which poses a problem in differential diagnosis when PV presents as isolated erythrocytosis. Characteristic features of PV are erythropoietin (Epo)-independent in vitro erythroid colony formation, as well as hypersensitivity to many other hematopoietic growth factors. Recently, a remarkable association between PV and a somatic point mutation of the
JAK2
tyrosine kinase (
JAK2
V617F) was described. Functional assays have revealed that
JAK2
V617F is capable of inducing constitutive STAT5-mediated signaling in vitro, as well as erythrocytosis in vivo in mice. These data suggest that the
JAK2
V617F mutation participates in the pathogenesis of PV. In current clinical practice, two different clinical approaches have been used to diagnose PV. One approach requires establishing the presence of absolute erythrocytosis by directly determining the red cell mass (RCM). A second approach utilizes a RCM-independent diagnostic algorithm based on the serum Epo level and bone marrow histology. Screening for
JAK2
V617F can now be added to both diagnostic algorithms. However, it is very clear that some patients with classical PV lack the
JAK2
V617F mutation, while some patients with other chronic myeloproliferative disorders such as idiopathic myelofibrosis (IMF) and essential thrombocytosis (ET) also express the
JAK2
V617F mutation. Therefore, by necessity, any discussion of PV must take into consideration these companion myeloproliferative disorders, and since erythrocytosis is the single clinical feature that sets PV apart from IMF and ET, it is clear that the presence of the
JAK2
V617F mutation cannot by itself establish a diagnosis of PV. Phlebotomy remains the mainstay of therapy for PV. In addition, both aspirin and cytoreductive therapy have been employed to control
thrombocytosis
and in the case of the latter, leukocytosis and extramedullary hematopoiesis as well. Despite recent progress in the field, several important issues remain controversial. In this review, we will present the areas of agreement, but also point out where the authors' personal viewpoints differ.
...
PMID:Polycythemia vera: scientific advances and current practice. 1621 34
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