OBJECTIVETo investigate the prevalence of JAK2V617F and MPLW515L/K mutation in patients with slightly elevated platelets (BPC) or hemoglobin (Hb) not meeting the criteria of polycythemia vera (PV) or essential thrombocythemia (ET).

METHODSGenomic DNA from bone marrow or blood mononuclear cells was screened with allele specific polymerase chain reaction (AS-PCR) for JAK2V617F and MPLW515L/K mutation. The history of thrombosis was assessed retrospectively by patients files.

RESULTSOf 30 patients, 14 (46.7%) were positive for the JAK2V617F mutation, none of them had the MPLW515L/ K. Five of these 14 patients had a history of thrombosis. Follow-up results were available in 22 patients. Among them, 12 patients with JAK2V617F mutation turned out to be MPD in 6-24 months; only 2 out of 10 patients without this mutation evolved to MPD.

CONCLUSIONJAK2V617F mutation could be one of the diagnosis criteria of early MPD. No MPLW515L/K expression was found in early MPD.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Early Diagnosis ; Female ; Follow-Up Studies ; Humans ; Janus Kinase 2 ; genetics ; metabolism ; Male ; Middle Aged ; Mutation ; Myeloproliferative Disorders ; diagnosis ; genetics ; metabolism ; Receptors, Thrombopoietin ; genetics ; metabolism ; Young Adult

BACKGROUND: We investigated the Janus kinase 2 (JAK2) mutation and its diagnostic value in patients suffering with non BCR/ABL myeloproliferative diseases (nMPD) or other reactive conditions. METHODS: We reviewed the clinical records of 83 patients who underwent bone marrow (BM) examinations with suspect of nMPD. The diagnoses of nMPD were made based on the WHO criteria since 2001 and the PVSG criteria before 2001. The JAK2 mutation was examined by PCR in 54 patients whose BM samples were available. RESULTS: The JAK2 mutation was detected in 25 patients (46%); 12 of 26 patients with essential thrombocythemia (ET), 9 of 12 patients with polycyhtemia vera (PV), one of 7 patients with chronic idiopathic myelofibrosis (CIM) and one patient with unclassifiable MPD. Additionally, JAK2 mutation was detected in each one patient with secondary polycythemia and reactive thrombocytosis. These two patients and two other patients among the JAK2 mutated ET did not meet the WHO PV criteria due to their initial low hemoglobin levels. These patients had liver cirrhosis and hypersplenism due to Budd-Chiari syndrome (1), gastrointestinal bleeding (1) or the initial hemoglobin level was slightly below the level as provided by the criteria, but the level showed a rising pattern despite cytoreductive therapy (2). With the results of the JAK2 mutation available, 4 patients' disease could be re-diagnosed as PV. Finally, the positive rate of the JAK2 mutation was 81% in PV, 48% in ET and 14% in CIM. The presence of JAK2 mutation closely correlated with PV (p=0.001), leukocytosis (p=0.001) and an increased cellularity of BM (p=0.024). CONCLUSIONS: The JAK2 mutation may help differentiate nMPD from secondary cytosis. Therefore, it should be incorporated into the guidelines for the nMPD work-up for making a more accurate diagnosis and administering proper treatment.
Retrospective Studies ; Proto-Oncogene Proteins c-bcr ; Polymerase Chain Reaction ; Myeloproliferative Disorders/*diagnosis/genetics/metabolism ; *Mutation ; Middle Aged ; Male ; Janus Kinase 2/*genetics ; Humans ; Genes, abl ; Female ; Diagnosis, Differential ; DNA/*genetics ; Biological Markers/metabolism ; Aged, 80 and over ; Aged ; Adult

Adenosine Triphosphate ; metabolism ; Colorectal Neoplasms ; diagnosis ; genetics ; DNA Methylation ; Diphosphates ; metabolism ; Glioma ; diagnosis ; genetics ; Humans ; Isocitrate Dehydrogenase ; genetics ; Janus Kinase 2 ; genetics ; Mutation ; Myeloproliferative Disorders ; diagnosis ; genetics ; Polymorphism, Single Nucleotide ; Proto-Oncogene Proteins ; genetics ; Proto-Oncogene Proteins p21(ras) ; Sequence Analysis, DNA ; methods ; Templates, Genetic ; ras Proteins ; genetics

BACKGROUND: Mutations in calreticulin (CALR) have been reported to be key markers in the molecular diagnosis of myeloid proliferative neoplasms. In most previous reports, CALR mutations were analyzed by using Sanger sequencing. Here, we report a new, rapid, and convenient system for screening CALR mutations without sequencing. METHODS: Eighty-three bone marrow samples were obtained from 81 patients with thrombocytosis. PCR primers were designed to detect wild-type CALR (product: 357 bp) and CALR with type 1 (product: 302 bp) and type 2 mutations (product: 272 bp) in one reaction. The results were confirmed by Sanger sequencing and compared with results from fragment analysis. RESULTS: The minimum detection limit of the screening PCR was 10 ng for type 1, 1 ng for type 2, and 0.1 ng for cases with both mutations. CALR type 1 and type 2 mutants were detected with screening PCR with a maximal analytical sensitivity of 3.2% and <0.8%, respectively. The screening PCR detected 94.1% (16/17) of mutation cases and showed concordant results with sequencing in the cases of type 1 and type 2 mutations. Sanger sequencing identified one novel mutation (c.1123_1132delinsTGC). Compared with sequencing, the screening PCR showed 94.1% sensitivity, 100.0% specificity, 100.0% positive predictive value, and 98.5% negative predictive value. Compared with fragment analysis, the screening PCR presented 88.9% sensitivity and 100.0% specificity. CONCLUSIONS: This screening PCR is a rapid, sensitive, and cost-effective method for the detection of major CALR mutations.
Adult ; Aged ; Base Sequence ; Bone Marrow/metabolism ; Calreticulin/chemistry/*genetics/metabolism ; DNA Mutational Analysis ; Female ; Follow-Up Studies ; Genotype ; Humans ; Janus Kinase 2/chemistry/genetics/metabolism ; Male ; Middle Aged ; Mutation ; Myeloproliferative Disorders/complications/*diagnosis/genetics ; Polymerase Chain Reaction ; Thrombocytosis/complications/*diagnosis

BACKGROUND: JAK2 genetic variations have been described in a high proportion of patients with BCR/ABL1-negative myeloproliferative neoplasms (MPN). This study was designed to analyze the frequencies of JAK2 V617F and exon 12 variations, and their correlations with clinical characteristics of Korean patients with BCR/ABL1-negative MPN. METHODS: We examined a total of 154 patients with BCR/ABL1-negative MPN that included 24, 26, 89, and 15 patients with polycythemia vera (PV), primary myelofibrosis (PMF), essential thrombocythemia (ET), and unclassified myeloproliferative neoplasms (MPNU), respectively. We performed allele-specific PCR to detect V617F in all BCR/ABL1-negative patients, and performed direct sequencing to detect exon 12 variations in 47 V617F-negative MPN patients. JAK2 c.1641+179_183del5 variation was detected by restriction fragment length polymorphism assay in 176 healthy subjects. RESULTS: JAK2 V617F was detected in 91 patients (59.1%): PV (91.6%), PMF (46.2%), ET (52.8%), and MPNU (66.7%). In V617F-negative MPN patients, no mutations were found in exon 12. The c.1641+179_183del5 was detected in 68.1% of V617F-negative MPN patients and 45.4% of healthy subjects (P=0.008). JAK2 V617F was closely correlated with age and leukocytosis in BCR/ABL1-negative MPN patients (P<0.05). However, c.1641+179_183del5 was not related to age, sex, or complete blood cell count parameters in V617F-negative MPN patients and healthy subjects. The c.1641+179_183del5 was associated with an increased odds ratio for MPN (odds ratio, 2.6; 95% confidences interval, 1.3-5.1; P=0.007). CONCLUSIONS: Frequencies of V617F are similar to reported results. JAK2 exon 12 mutations may be rare and c.1641+179_183del5 may influence the occurrence of MPN in Korean patients with V6 17F-negative MPN.
Adolescent ; Adult ; Age Factors ; Aged ; Aged, 80 and over ; Alleles ; Amino Acid Substitution ; Asian Continental Ancestry Group/*genetics ; Child ; Exons ; Female ; Fusion Proteins, bcr-abl/*metabolism ; *Genetic Variation ; Humans ; Janus Kinase 2/*genetics ; Male ; Middle Aged ; Myeloproliferative Disorders/diagnosis/*genetics ; Odds Ratio ; Polymorphism, Restriction Fragment Length ; Republic of Korea ; Sequence Analysis, DNA

Polycythemia vera, essential thrombocythemia, and primary myelofibrosis are collectively known as 'Philadelphia-negative classical myeloproliferative neoplasms (MPNs).' The discovery of new genetic aberrations such as Janus kinase 2 (JAK2) have enhanced our understanding of the pathophysiology of MPNs. Currently, the JAK2 mutation is not only a standard criterion for diagnosis but is also a new target for drug development. The JAK1/2 inhibitor, ruxolitinib, was the first JAK inhibitor approved for patients with intermediate- to high-risk myelofibrosis and its effects in improving symptoms and survival benefits were demonstrated by randomized controlled trials. In 2011, the Korean Society of Hematology MPN Working Party devised diagnostic and therapeutic guidelines for Korean MPN patients. Subsequently, other genetic mutations have been discovered and many kinds of new drugs are now under clinical investigation. In view of recent developments, we have revised the guidelines for the diagnosis and management of MPN based on published evidence and the experiences of the expert panel. Here we describe the epidemiology, new genetic mutations, and novel therapeutic options as well as diagnostic criteria and standard treatment strategies for MPN patients in Korea.
Antineoplastic Agents/*therapeutic use ; Asian Continental Ancestry Group/genetics ; Humans ; Janus Kinase 2/*antagonists & inhibitors/genetics/metabolism ; Molecular Targeted Therapy ; Mutation ; Myeloproliferative Disorders/diagnosis/drug therapy/enzymology/ethnology/genetics ; Protein Kinase Inhibitors/*therapeutic use ; Republic of Korea/epidemiology ; Risk Factors ; Signal Transduction/drug effects ; Treatment Outcome