We evaluated the incidence, clinical characteristics, and prognostic impact of calreticulin (CALR) mutations in essential thrombocythemia (ET) and primary myelofibrosis (PMF) patients. In all, 48 ET and 14 PMF patients were enrolled, and the presence of CALR mutations was analyzed by direct sequencing. Patients were classified into three subgroups according to Janus kinase 2 (JAK2) V617F and CALR mutation status, and their clinical features and prognosis were compared. CALR mutations were detected in 15 (24.2%) patients, and the incidence increased to 50.0% in 30 JAK2 V617F mutation-negative cases. These included 11 patients with three known mutations (c.1092_1143del [seven cases], c.1154_1155insTTGTC [three cases], and c.1102_1135del [one case]) and 4 patients with novel mutations. ET patients carrying CALR mutation were younger, had lower white blood cell counts, and experienced less thrombosis during follow-up than those carrying JAK2 V617F mutation, while both patient groups showed similar clinical features and prognosis. In ET patients without JAK2 V617F mutation, CALR mutation did not significantly affect clinical manifestation and prognosis. In conclusion, CALR mutation analysis could be a useful diagnostic tool for ET and PMF in 50% of the cases without JAK2 V617F mutations. The prognostic impact of CALR mutations needs further investigation.
Adult ; Aged ; Calreticulin/*genetics ; DNA Mutational Analysis ; Exons ; Female ; Genotype ; Humans ; INDEL Mutation ; Janus Kinase 2/genetics ; Male ; Middle Aged ; Primary Myelofibrosis/diagnosis/epidemiology/*genetics ; Prognosis ; Republic of Korea ; Tertiary Care Centers ; Thrombocythemia, Essential/diagnosis/epidemiology/*genetics ; Young Adult

JAK2 V617F and MPL W515L/K mutations have been reported in approximately 50% and 5% of the patients with essential thrombocythemia (ET), respectively. We investigated the frequency of MPL W515L/K mutations in a series of consecutive patients with ET and post-essential thrombocythemia myelofibrosis (post-ET MF). The study subjects were 63 patients diagnosed either with ET (N=59) or post-ET MF (N=4) at our institution between June 2006 and February 2010. Among them, 35 (55.6%) had the JAK2 V617F mutation. MPL W515L/K mutations were detected by direct sequencing analyses of exon 10, and 2 patients were found to harbor the following MPL mutations: W515L in 1 patient with ET and W515K in 1 patient with post-ET MF. Neither of the patients had the JAK2 V617F mutation. The frequencies of the MPL W515L/K and JAK2 V617F-negative mutations in our subjects with ET/post-ET MF were 3.2% (2/63) and 7.1% (2/28), respectively. This is the first study to report the frequency of JAK2 V617F and MPL W515L/K mutations in Korean patients with ET/post-ET MF.
Aged ; Amino Acid Substitution ; Asian Continental Ancestry Group/*genetics ; Exons ; Female ; Humans ; Janus Kinase 2/*genetics ; Male ; Middle Aged ; *Mutation ; Polycythemia Vera/genetics ; Receptors, Thrombopoietin/*genetics ; Republic of Korea ; Sequence Analysis, DNA ; Thrombocythemia, Essential/diagnosis/*genetics

This study was aimed to investigate the clinical, pathological and biological features of a special case of chronic myeloid leukemia (CML) with marked thrombocythemic onset. The morphological changes of cells were analyzed by using bone marrow smear and biopsy; Ph chromosome, a specific marker of CML, was assayed by conventional chromosomal analysis and fluorescence in situ hybridization, bcr/abl fusion gene was detected by reverse transcription-polymerase chain reaction. The results indicated that CML mimicked essential thrombocythemia (ET) at presentation was relatively rare and might be misdiagnosed as ET, bone marrow smear and biopsy revealed, marked thrombocytosis and moderate leukocytosis; RT-PCR, FISH and conventional chromosomal analysis demonstrated the existence of Ph chromosome and bcr/abl fusion gene. This special CML could progress into accelerated phase or blast crisis. The megakaryocytes in Ph+ ET were smaller than normal ones and had typically hypolobulated round nuclei. Patients diagnosed as Ph+ ET might progress into CML and showed a high tendency to myelofibrosis and blastic transformation. It is concluded that the value of routine cytogenetical and molecular biological analysis in diagnosis for potential CML cases, which mimicked ET as in this presentation, is very distinctive, and the importance is magnified by the recent availability of imatinib, a specific inhibitor of the bcr/abl tyrosine kinase produced by the Philadelphia chromosome. Every case of "ET" should be tested for the Philadelphia chromosome and bcr/abl transcript.
Adult ; Diagnosis, Differential ; Female ; Fusion Proteins, bcr-abl ; genetics ; Gene Rearrangement ; Humans ; In Situ Hybridization, Fluorescence ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; complications ; diagnosis ; genetics ; Megakaryocytes ; pathology ; ultrastructure ; Philadelphia Chromosome ; Reverse Transcriptase Polymerase Chain Reaction ; Thrombocythemia, Essential ; diagnosis

To evaluate the frequency of jak2v617f mutation and analyze its correlation with clinical features of primary thrombocythemia (PT) patients, the mutation was detected by allele specific polymerase chain reaction (AS-PCR), the clinical and laboratory data in 66 PT patients with and without jak2v617f mutation were compared and clinical features of these PT patients were retrospectively analyzed. The results showed that among 66 patients, 27 patients (41%) had the mutation. The patients carrying the mutation displayed higher bone marrow erythropoiesis (26.9%+/-9.4% vs 16.3%+/-8.7%, p<0.05), higher ratio of granulopoiesis/erythropoiesis (2.9+/-1.8 vs 5.2+/-2.9, p<0.05) and higher incidence of microvascular disturbances (29.6% vs 5.1%, p<0.05). However, the age, gender, leukocyte and platelet counts, hemoglobin level, bone granulopoiesis, splenomegaly, history of thrombosis and hemorrhage had no difference between patients with and without the mutation. It is concluded that the frequency of jak2v617f mutation in primary thrombocythemia patients is 41%. The presence of the jak2v617f mutation is associated with a higher bone marrow erythropoiesis in primary thrombocythemia patients at diagnosis.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Alleles ; Erythropoiesis ; Female ; Humans ; Janus Kinase 2 ; genetics ; Male ; Middle Aged ; Point Mutation ; Polymerase Chain Reaction ; methods ; Retrospective Studies ; Thrombocythemia, Essential ; diagnosis ; genetics ; Young Adult

No abstract available.
Adult ; Biomarkers, Tumor/genetics ; Bone Marrow/pathology ; Calreticulin/genetics ; Erythropoietin/blood ; Female ; Fusion Proteins, bcr-abl/*genetics ; Hematocrit ; Hemoglobins/analysis ; Humans ; Janus Kinase 2/genetics ; Male ; Middle Aged ; Mutation ; Myeloproliferative Disorders/*diagnosis/genetics ; Polycythemia Vera/*diagnosis/genetics ; Receptors, Thrombopoietin/genetics ; Thrombocythemia, Essential/diagnosis ; World Health Organization

No abstract available.
Adolescent ; Adult ; Age Factors ; Aged ; Aged, 80 and over ; Amino Acid Sequence ; Calreticulin/*genetics ; Child ; DNA/chemistry/genetics/metabolism ; Exons ; Female ; Humans ; Janus Kinase 2/*genetics ; Male ; Middle Aged ; Molecular Sequence Data ; Polymorphism, Single Nucleotide ; Receptors, Thrombopoietin/genetics ; Sequence Analysis, DNA ; Sex Factors ; Thrombocythemia, Essential/*diagnosis/genetics ; Young Adult