Detection of the JAK2 V617F Mutation by Real Time PCR in Granulocytes and Platelets of ET Patients.

Abstract Introduction. The JAK2 V617F mutation has been detected in 23%–57% of ET patients by direct sequencing or allele-specific (AS) PCR. It remains unknown, however, if the mutation detected in the granulocyte population, may be equally detected in platelets from these patients. Objective. To compare the detection of the JAK2V617F mutation in granulocytes and platelets from ET patients by real time AS RT-PCR. Patients and methods. Platelets and granulocytes from 50 ET patients from a single institution were studied. Patients were diagnosed according to the WHO criteria. At the time when JAK2 mutation was analyzed 16/50 patients were receiving platelet-lowering therapy ± ASA, 14/50 patients only received ASA and 20/50 received no specific treatment. JAK2 mutation was analyzed by real-time AS RT-PCR with probes specific for the mutated and the wild type form. Results. The V617F JAK2 mutation was detected in 18 out of 50 patients in both granulocytes and platelets by real time AS RT-PCR, and was negative in both cell populations in the remaining 32 patients. In the V617F JAK2 positive cases, the mean Ct(V617FJAK2)/Ct(wild type JAK2) ratio was 1.074±0.062 for granulocytes and 1.038±0.039 for platelets (p=0.048). These values corresponded to a 17.79 ±7.4% of mutated population when granulocytes were analyzed, whereas, a significantly higher percentage of mutated population was observed, 23.45±7.78 %, when platelets were analyzed (p=0.032). Conclusions. The results of V617FJAK2 mutation detection by AS RT-PCR were the same in granulocytes and platelets (either positive or negative). The percentage of clonal population detected in ET patients was significantly higher in platelets than in granulocytes.

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JAK2 (V617F) Mutation Status and Neutrophil Apoptotic Resistance in Myelofibrosis with Myeloid Metaplasia (MMM): Correlation and Potential Identification through Phosphorylation Status of STAT3.

Blood ◽

10.1182/blood.v106.11.3503.3503 ◽

2005 ◽

Vol 106 (11) ◽

pp. 3503-3503

Author(s):

Ruben A. Mesa ◽

Ayalew Tefferi ◽

Heather Powell ◽

Terra Lasho ◽

David Loegering ◽

...

Keyword(s):

Jak2 V617f ◽

Jak2 V617f Mutation ◽

Neutrophil Apoptosis ◽

Wild Type ◽

Jak2 Mutation ◽

Myeloid Metaplasia ◽

Mutation Status ◽

Stat3 Phosphorylation ◽

V617f Mutation ◽

Myelofibrosis With Myeloid Metaplasia

Abstract Background: We have previously described a resistance to the normal process of apoptosis in neutrophils of patients with myelofibrosis with myeloid metaplasia (MMM) (Blood2003;102:11). Most recently, an activating mutation of JAK2 (V617F) has been described in approximately half of the patients with MMM as well as in variable proportion of patients with other myeloproliferative disorders (MPD). In the current study, we investigated the correlation between JAK2 V617F mutation status and neutrophil apoptosis in MMM. Methods: Neutrophils were isolated by density centrifugation from patients with MMM, other MPDs, and normal controls and assessed for apoptosis at baseline and after 24 hours in culture (IMDM with 20% sterilized fetal calf serum to simulate spontaneous apoptosis). Apoptosis was quantified using three-color flow cytometry using CD45 (to confirm leukocyte presence), annexin V (AN) (marker of apoptosis; detects aberrant externalization of phosphatidylserine during apoptosis), and propidium iodide (PI) (marker of dead cells). Mutation analysis for JAK2 V617F was performed in DNA derived from the isolated neutrophils using genomic DNA amplified by PCR, or extracted from cytogenetic pellets in archived specimens. Apoptotic rates after 24 hours in culture were correlated between patients and controls for both JAK2 mutation status and clinical parameters. Immunoblotting was performed on a subset of patients for correlation of JAK2 mutation status and downstream phosphorylation of the JAK2 target, STAT3, which transcriptionally activates several antiapoptotic genes. Results: Spontaneous neutrophil apoptosis was significantly decreased in MMM patients (n=50; median % apoptotic cells at 41%) compared to both healthy volunteers (n=9; 66%) and patients with other MPD (n=11; 53%) (p=0.002). Resistance to apoptosis in MMM correlated with both anemia (p=0.01) and the presence of the JAK2 V617F mutation (p=0.01). Furthermore, the specific abnormality was more pronounced in patients with homozygous JAK2 V617F; median % apoptotic cells of 47% for patients with wild-type allele (n=22) vs. 39% for heterozygotes (n=23) vs. 22% for homozygotes (n=5; p=0.008). The JAK2 mutation status did not appear dependent on other peripheral blood or clinical features. Neutrophils from 14 MMM patients were assessed simultaneously for both JAK2 mutation and STAT3 phosphorylation status by immunoblotting. Strong expression of phosphorylation of STAT3 was seen in all 3 homozygotes and 4 of 5 heterozygotes, but only 1 of 6 with wild-type allele (p=0.026). Conclusions: Impaired neutrophil apoptosis in patients with MMM correlates with the functional presence of JAK2 V617F in an allele-dose dependent manner and STAT3 phosphorylation. The current observation supports a pathogenetic role for the specific mutation in sustaining clonal myeloproliferation.

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Homologous Recombination of Wild TYPE JAK2, A NOVEL EARLY STEP In the DEVELOPMENT of Myeloproliferative Neoplasm

Blood ◽

10.1182/blood.v118.21.2805.2805 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2805-2805

Author(s):

Mathias Vilaine ◽

Damla Olcaydu ◽

Ashot Harutyunyan ◽

Jonathan Bergeman ◽

Tiab Mourad ◽

...

Keyword(s):

Homologous Recombination ◽

Snp Array ◽

Myeloproliferative Neoplasm ◽

Jak2 V617f ◽

Jak2 V617f Mutation ◽

Wild Type ◽

Jak2 Mutation ◽

Chromosome 9P ◽

V617f Mutation ◽

Array Analyses

Abstract Abstract 2805 Background: Adequate expression and function of Jak2 in hematopoietic progenitors is critical for normal myelopoiesis. The JAK2 46/1 (GGCC) haplotype, a congenital particularity, predisposes to myeloproliferative neoplasm (MPN) both independently and through mutation of the JAK2 gene. The JAK2 V617F mutation and acquired homozygous status for JAK2 V617F are frequent in MPN. JAK2 V617F homozygosity is currently explained acquisition of the JAK2 V617F mutation followed by mitotic homologous recombination (HR) of JAK2 occurred between wild-type and mutant alleles, leading to uniparental disomy (UPD) of chromosome 9p (9pUPD). Here we report the cases of 2 PV patients (Na1061 and Na1253) with acquired homozygous status for the JAK2 46/1 haplotype yet their granulocytes carried <20% JAK2 V617F. Aim: To determine whether HR of JAK2 can precede the V617F mutation in MPN. Methods: Granulocyte DNA and CD3+ lymphocyte DNA were examined in parallel with qPCR assays specific for the wild type and 46/1 haplotypes using rs12343867, a JAK2 intron 14 marker, as well as 4 other single nucleotide polymorphisms (SNP) on chromosome 9p. 9pUPD clonality and length were determined using SNP array studies. Results: For both patients, lymphocytes were heterozygous for the 46/1 haplotype, confirming that granulocyte 46/1 homozygosity was acquired. Direct sequencing of the JAK2 and GNE genes and SNP array analyses revealed homologous recombination of part of the JAK2 gene (exons 6–19, patient Na1061) and of the complete 46/1 JAK2 haplotype (patient Na1253). Furthermore, for both patients, full length sequencing of JAK2 cDNA revealed no additional mutation. In both cases, HR of wild-type JAK2 was associated with growth advantage and high expression of recombined JAK2. For both patients, further SNP array analyses revealed partial 9pUPD concerning <30% cells, which correlated with %JAK2 V617F and was consistent with 9pUPD having occurred after JAK2 V617F (Figure 1). The distortion of SNP allelic differences was higher at the telomeric end than in the centromeric region of chr. 9p. This indicated 2 distinct partial 9pUPDs for Na1061 and 1 partial 9pUPD for Na1253. Conclusion: Homologous recombination involving wild type JAK2 can precede JAK2 mutation and 9pUPD in MPN. Thus multiple paths and diverse alterations of the JAK2 gene can lead to MPN in individuals carrying the JAK2 GGCC haplotype. We propose a new model with JAK2 HR as early event, followed or not by JAK2 mutation, or/and JAK2 mutation(s) facilitating subsequent recombination resulting in 9pUPD and JAK2 V617F homozygosity. Disclosures: No relevant conflicts of interest to declare.

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JAK2 V617F Mutation Is Infrequent in “5q-Syndrome” and 5q-Associated MDS.

Blood ◽

10.1182/blood.v108.11.4833.4833 ◽

2006 ◽

Vol 108 (11) ◽

pp. 4833-4833

Author(s):

Ling Zhang ◽

Saskia Gueller ◽

Sophie Raynaud ◽

Phillip H. Koeffler ◽

Stephen Lee

Keyword(s):

Bone Marrow ◽

Chromosomal Abnormalities ◽

Bone Marrow Aspiration ◽

K562 Cells ◽

Jak2 V617f ◽

Janus Kinase ◽

Jak2 V617f Mutation ◽

Wild Type ◽

Jak2 Mutation ◽

V617f Mutation

Abstract Background: V617F mutation in Janus Kinase 2 (JAK2) gene has been found in chronic myeloproliferative disorders (MPD) including polycythemia vera (90%), essential thrombocythemia and chronic idiopathic myelofibrosis (30–50%), and occasionally in myelodysplastic syndromes (MDS). “5q- Syndrome” is a MDS that shares features with MPD and characterized by an atypical megakaryocytic hyperplasia in bone marrow and usually thrombocytosis in peripheral blood. The most common deleted region for this syndrome is 5q13.3q33.1. An interstitial deletion with variable proximal (5q12-14) and distal (5q31-33) breakpoints has been found in other MDS with/without additional chromosomal abnormalities beyond “5q- Syndrome”. To date, JAK2 mutation was detected in 6/97(6.2%) of patients having diagnosis of MDS with “5q- Syndrome”. Design: In our study 21 MDS patients (10 with “5q- Syndrome” and 11 MDS with isolated or complex 5q-) whose diagnosis by both bone marrow aspiration/biopsy and conventional chromosomal analysis were confirmed. Materials and Method: Primers were created to amplify a 460 bp fragment containing the site of JAK2 V617F mutation. Forty-five cycles of PCR were performed at an annealing temperature of 57°C. Resulting PCR product was digested with 2 U BsaXI for 16 hours and with an additional 2 U BsaXI for another 16 hours at 37°C, then analyzed on a 2% agarose gel. The mutant allele remained undigested whereas the wild-type allele was digested into 241 bp, 189 bp and 30 bp fragments. All experiments included a positive (HEL cells) and negative (K562 cells) control. Results: PCR results showed clear wild type PCR patterns in all 21 cases. Conclusion: No JAK2 mutations were detected in 21 patients either with “5q- Syndrome” or other 5q- associated MDS suggesting that JAK2 mutations are infrequent in these MDS patients.

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Frequency of the JAK2 Mutation and Its Usefulness as a Marker for Treatment Response and Disease Progression in Korean Patients with Chronic Myeloproliferative Disorders.

Blood ◽

10.1182/blood.v108.11.4876.4876 ◽

2006 ◽

Vol 108 (11) ◽

pp. 4876-4876 ◽

Cited By ~ 1

Author(s):

Myung-Geun Shin ◽

Hyeoung Joon Kim ◽

Hye-Ran Kim ◽

Sun-Young Lee ◽

Il-Kwon Lee ◽

...

Keyword(s):

Disease Progression ◽

Treatment Response ◽

Real Time ◽

Real Time Pcr ◽

Jak2 V617f ◽

Jak2 V617f Mutation ◽

Quantitative Real Time Pcr ◽

Jak2 Mutation ◽

Korean Patients ◽

V617f Mutation

Abstract Background: The recent discovery of a single point mutation in the JAK2 gene (V617F) is a major advance in our understanding of the pathogenesis of BCR/ABL-negative chronic myeloproliferative disorders (CMPD). The frequency of the JAK2 V617F mutation in CMPD differs according to methods and research groups. We investigated the frequency of JAK2 mutations in Korean CMPD patients and demonstrated their usefulness as a new molecular marker for treatment response and disease progression in BCR/ABL-negative CMPD using quantitative real time PCR and pyrosequencing. Methods: Seventy-eight patients with BCR/ABL-negative CMPD comprising 42 cases of essential thrombocythemia (ET), 26 of polycythemia vera (PV), 7 with idiopathic myelofibrosis (MF), and 3 unclassifiable (UC) CMPD were enrolled in this study. A 364-bp PCR product containing the JAK2 V617F mutation was sequenced in both directions from total bone marrow cells. Restriction enzyme-based assessment with BsaXI was also used to search for JAK2 mutations. A quantitative real-time PCR-based allelic discrimination assay and pyrosequencing (Pyrosequencer PSQ96) were used to quantify the JAK2 V617F mutation status. Results: A single JAK2 V617F point mutation was identified in 20 (77%) of 26 patients with PV, 12 (26%) of 42 with ET, 7 (100%) of 7 with MF, and 2 (67%) of 3 with UC. The V617F mutation was present in over half of Korean patients with BCR/ABL-negative CMPD, giving an overall frequency of 53%. The proportion of mutant alleles ranged from 36 to 100% in the real-time PCR and pyrosequencing analysis. Patients with MF had a higher percentage of JAK2 mutant alleles than patients with ET (MF>PV>ET). PV patients (n=8) with a good response (phlebotomy only) had a relatively low proportion (58.9±20.1%) of the JAK2 mutant, while patients (n=9) showing a poor response (additional chemotherapy) initially had a higher proportion (76.6±19.0%; p=0.04185). Conclusion: The frequency of the JAK2 V617F mutation in Korean patients with PV was lower than that in reports from Western countries, although the overall frequency in Korean patients with BCR/ABL-negative CMPD was similar to previous reports. The results also suggest that the JAK2 mutation (quantification of JAK2 mutant alleles) can be used as a new marker for treatment response and disease progression in BCR/ABL-negative CMPD using quantitative real-time PCR or pyrosequencing.

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Myeloid Blasts in Transformed JAK2-V617F Positive Myeloproliferative Disorders Are Frequently Negative for the JAK2-V617F Mutation.

Blood ◽

10.1182/blood.v108.11.375.375 ◽

2006 ◽

Vol 108 (11) ◽

pp. 375-375 ◽

Cited By ~ 4

Author(s):

Alexandre Theocharides ◽

Marjorie Boissinot ◽

Richard Garand ◽

François Girodon ◽

Soon-Siong Teo ◽

...

Keyword(s):

De Novo ◽

Jak2 V617f ◽

Myeloproliferative Disorders ◽

Jak2 V617f Mutation ◽

Jak2 Mutation ◽

Allelic Ratio ◽

Pcr Products ◽

Blast Cells ◽

V617f Mutation ◽

De Novo Aml

Abstract Acute myeloid leukemia (AML) is a common complication of myeloproliferative disorders (MPDs). The role of the JAK2-V617F mutation in this process is unknown. We performed a retrospective analysis of DNA samples from MPD patients with secondary AML. We analysed DNA samples taken at the time of transformation to AML from 54 MPD patients (24 PV, 21 ET, 9 IMF). In addition, DNA samples taken at diagnosis of MPD were obtained in 21 of these patients. DNA was extracted from bone marrow or peripheral blood films, purified granulocytes or frozen cells. FACS sorting of blast cells, T cells and neutrophils was performed in some of the samples. The allelic ratio of JAK2-V617F was determined by allele-specific quantitative PCR (AS-PCR). We obtained AS-PCR data on 52/54 samples taken at the time of transformation (96%), whereas 2 samples did not yield PCR products: 24/52 samples were negative for JAK2-V617F (46%) and 28/52 were positive (54%). For 14/24 negative patients (58%) we had additional DNA samples taken at the time of MPD diagnosis and interestingly, 5 of these 14 patients (36%) were positive for JAK2-V617F at this earlier time point before AML transformation. This suggests that in these patients the JAK2-V617F positive clone was lost during the evolution to AML. Furthermore, comparison of the JAK2-V617F allelic ratios with the percentage of blast cells in patient samples positive at transformation revealed 8/28 cases where the JAK2-V617F allelic ratio was markedly lower than the percentage of blasts, e.g. 8%T-allele and 52% myeloid blast cells. In these patients a JAK2-V617F negative AML clone most likely co-exists with a JAK2-V617F positive MPD clone. To address the question whether the AML clone arose independently from the JAK2-V617F clone, we analyzed loss of heterozygosity on chromosome 9p (9pLOH) in one informative patient who displayed a high allelic ratio of mutant JAK2 at diagnosis (94%T). The CD15+ cells from this patient showed 9pLOH at diagnosis, as demonstrated with two independent microsatellite markers. In contrast, the FACS sorted blast cells at the time of transformation contained both parental alleles in the 9p region and were JAK2-V617F negative by AS-PCR. This excludes the possibility that the AML clone lost the JAK2V617F in the process of undergoing mitotic recombination at a stage heterozygous for JAK2-V617F. Analysis of additional patients is under way. In summary, we found in a cohort of 54 MPD patients, 13 patients initially positive for JAK2-V617F that transformed into JAK2-V617F negative AML. Although not confirmed in the one patient analyzed, we cannot exclude that other patients the JAK2-V617F positive MPD clone lost the JAK2 mutation during the process of transformation. Alternatively, the AML clone could have developed de novo from a JAK2-V617F negative progenitor or stem cell. The latter model has difficulties explaining the high incidence of de novo AML (8/54 patients), unless the JAK2-V617F negative progenitor already carried an as yet unknown mutation and was part of the MPD clone.

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Correlation of JAK2 V617F Mutation Status and Cytogenetic Findings in Myeloproliferative Disorders.

Blood ◽

10.1182/blood.v108.11.3633.3633 ◽

2006 ◽

Vol 108 (11) ◽

pp. 3633-3633

Author(s):

Guoxian Sun ◽

Frank Buccini ◽

Elizabeth Fuentes ◽

James Weisberger

Keyword(s):

Jak2 V617f ◽

Myeloproliferative Disorders ◽

Chromosome Abnormalities ◽

Jak2 V617f Mutation ◽

Homozygous Mutation ◽

Jak2 Mutation ◽

Mutation Status ◽

Trisomy 9 ◽

V617f Mutation ◽

Trisomy 9P

Abstract Detection of JAK2 V617F mutation is quickly becoming a front-line screening test for suspected myeloproliferative disorders (MPDs), as the mutation shows high frequency and specificity in non-CML MPDs, PV, ET or CIMF. Routine cytogenetics can detect chromosome abnormalities in approximately 20% of MPDs and is very helpful in establishing or confirming the presence of aberrant clonality, although chromosome changes are often numerical gains and losses, deemed non-specific. To see if there is correlation between JAK2 mutation and karyotypes, we studied 57 consecutive patients with clinically and morphologically confirmed diagnosis of non-CML MPDs. JAK2 V617F mutation performed using allele-specific PCR (sensitive to 10% using pyrosequencing) was found in 72% of patients (41/57), whereas clonal chromosome abnormalities were observed in 15.8% (9/57). There was no correlation between JAK2 mutational status and karyotypes. In 41 patients positive for the JAK2 mutation, 6 were cytogenetically abnormal and 35 normal. In 16 patients negative for the mutation, 3 showed abnormal karyotypes and 13 had normal karyotypes (X2 test, p>0.5). Among 6 patients with both JAK2 mutation and an abnormal karyotype, JAK2 mutation was seen in >50% of each sample in 4 patients, consistent with a homozygous mutation. Interestingly, in two cases, one with PV and trisomy 9 and another with MPD unclassifiable and trisomy 9p resulting from an unbalanced translocation between chromosomes 9p and 13, JAK2 mutation was present in >65% of each sample. Trisomy 9 and trisomy 9p are common abnormalities in MPDs, particularly in PV, seen in over 20% of cytogenetically abnormal cases. JAK2 gene is located on 9p24. Mitotic recombination is considered the most likely cause of loss of heterozygosity (LOH) and thus mutant homozygosity which is undetectable at the cytogenetic level. However, in cases with trisomy 9 or 9p, the JAK2 allele genotypes may be G/T/T and/or T/T/T as well as the usual G/T and/or T/T. Our observations suggest that trisomy 9 or 9p should be taken into consideration when interpreting JAK2 mutation status and that further molecular studies are needed to delineate the implication of trisomy 9 or 9p in potential mutant allele selective advantage and clonal evolution in JAK2 mutation positive MPDs.

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Presence of JAK2 V617F Mutation in Peripheral Blood of Blood Donors with Upper-Limit Hematocrit and Platelet Values.

Blood ◽

10.1182/blood.v110.11.2533.2533 ◽

2007 ◽

Vol 110 (11) ◽

pp. 2533-2533

Author(s):

Paola Bianchi ◽

Elisa Fermo ◽

Fulvio Mozzi ◽

Maurizio Marconi ◽

Alberto Zanella

Keyword(s):

Polycythemia Vera ◽

Blood Donors ◽

Jak2 V617f ◽

Jak2 V617f Mutation ◽

Myeloid Metaplasia ◽

Specific Pcr ◽

Upper Limit ◽

Allele Specific ◽

V617f Mutation ◽

Allele Specific Pcr

Abstract The somatic mutation V617F of JAK2 gene has been identified as a pathogenic factor in typical chronic myeloproliferative diseases (MPDs), in particular polycythemia vera, essential thrombocythemia, and myelofibrosis with myeloid metaplasia. Recently, two studies showed the presence of this mutation also in 37/3935 subjects with non haematological diseases (Xu et al, 2006) and 5/52 healthy donors (Sidon et al, 2006), suggesting that V617F mutation may occur in the absence of MPD phenotype and that probably is not sufficient per se to induce MPDs. The aim of this study was to search for the presence of JAK2 V617F mutation in healthy blood donors with confirmed upper-limit Hct and/or Plts values. Actually, previous studies indicated that some subjects with upper-limit Hct levels have early stages of polycythemia vera (Zanella et al, 1987). We studied 177 consecutive repeat blood donors (92 M, 85 F; median age 45 years, range 19–66) displaying Hct and/or Plts values higher than the 75° percentile of the normal reference distribution (Hct > 0.47 for M and > 0.42 for F; Plts > 300×109/L), confirmed on at least two different occasions in the last 12 months. All subjects had been accepted for blood donation on the basis of negative clinical history and normal results on both physical examination and routine laboratory testing. 83 of them (55 M and 28 F) had upper-limit Hct levels (median 0.48, range 0.47-0.51 for M; 0.43, range 0.42-0.47 for F); 85 had Plts > 300×109/L (median 338×109/L, range 300–454), and 9 donors had both upper-limit Hct and Plts. DNA was extracted from whole blood; all samples were analyzed by allele-specific polymerase chain reaction (PCR) according to Baxter et al (2005), and by fluorescent allele specific PCR (McClure et al, 2006) on ABI PRISM 310 Genetic Analyzer. Ten subjects were found to be positive for V617F mutation by fluorescent PCR, showing a positive signal when compared to a positive control corresponding to 2% of V617F mutated allele. Six of them showed a positive band also on agarose gel when analyzed with allele specific PCR. The presence of mutation was confirmed by enzymatic digestion with BsaXI. Hematological data of mutated subject are reported in the table. No statistically significant differences of hematological parameters were present between V617F positive and negative subjects. In conclusion, the presence of a V617F positive clone (albeit in a small amount), was found in 4% (3 F and 1 M) donors with upper-limit Hct and in 6% (2 F, 4 M) donors with Plts > 300×109/L. The follow up of these subjects will ascertain whether V617F mutation is a prelude to a myeloproliferative disease. Sex Age (years) Hb (g/dl) Hct Plts (×109/L) WBC (x109/L) Upper-limit Hct 1 F 66 15.1 0.45 202 4.85 2 F 51 14.4 0.43 235 6.40 3 F 64 15.7 0.45 198 7.75 4 M 58 15.9 0.48 220 7.30 Plts > 300×109/L 5 F 53 13.7 0.40 360 6.97 6 F 63 13.5 0.40 301 9.2 7 M 47 15.2 0.45 334 8.64 8 M 47 13.8 0.41 316 6.35 9 M 19 15.2 0.44 321 8 10 M 37 16.1 0.45 379 7.9

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Analysis of JAK2 V617F Mutation and Its Clinical Significance in Patients with Thrombocythemia and Other Myeloproliferative Neoplasms in Chinese

Blood ◽

10.1182/blood.v118.21.4687.4687 ◽

2011 ◽

Vol 118 (21) ◽

pp. 4687-4687

Author(s):

Yue Xu ◽

Changxin Yin ◽

Han He ◽

Lingling Shu ◽

Fuqun Wu ◽

...

Keyword(s):

Polycythemia Vera ◽

Essential Thrombocythemia ◽

Conflicts Of Interest ◽

Myeloproliferative Neoplasms ◽

Jak2 V617f ◽

Jak2 V617f Mutation ◽

Jak2 Mutation ◽

Western Countries ◽

Arms Pcr ◽

V617f Mutation

Abstract Abstract 4687 JAK2 mutation is commonly found in Philadelphia-negative myeloproliferative neoplasms (MPNs). In Western countries, this mutation is found in approximately 96 percent of people with polycythemia vera, half of individuals with essential thrombocythemia or primary myelofibrosis. We used the method of amplification refractory mutation PCR (ARMS-PCR) to investigate MPN patients in China. We focused our study on patients with essential thrombocythemia (ET). ARMS-PCR was used to detect JAK2 V617F mutation in the bone barrow (BM) or peripheral blood of 37 MPN patients, which consisting of 7 ET, 5 polycythemia vera (PV), 5 chronic myeloid leukemia (CML), 5 chronic idiopathic myelofibrosis (CIMF), as well as 15 suspected MPNs. 17 cases of JAK2 V617F mutation (45.9%) were found in 37 patients, including 4 ET (57.1%), 4 PV (80.0%), 3 CIMF (60.0%), 6 suspected MPNs (40.0%). We did not find JAK2 V617F in the patients with CML. Our results indicated that the frequency of JAK2 V617F mutation in bcr/abl-negative MPNs in Chinese is similar to that in MPN patients in Western countries. At the same time, ARMS-PCR can distinguish the mutation is heterozygous or homozygous. Most patients were heterozygous for JAK2 but only a few were homozygous. In conclusion, our study showed that JAK2 V617F mutation frequency in Chinese MPN patients is similar to that in patients with this disorder in the West. It is the major molecular genetic abnormality in bcr-abl negative MPN and it can be used for diagnosis of MPN in China. Disclosures: No relevant conflicts of interest to declare.

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Somatic mutation of the V617F JAK2 gene in patients of the cardiovascular diseases

Terapevticheskii arkhiv ◽

10.26442/00403660.2019.07.000245 ◽

2019 ◽

Vol 91 (7) ◽

pp. 25-28

Author(s):

I A Olkhovskiy ◽

A S Gorbenko ◽

M A Stolyar ◽

D A Grischenko ◽

O A Tkachenko ◽

...

Keyword(s):

Somatic Mutation ◽

Venous Blood ◽

Jak2 V617f ◽

Jak2 V617f Mutation ◽

Vascular Pathology ◽

Thrombotic Risk ◽

Cardiovascular Patients ◽

Allele Specific ◽

Polymerase Chain ◽

V617f Mutation

The JAK2 V617F somatic mutation is one of the most frequent markers of CHIP (clonal hematopoiesis of indeterminate potential). CHIP is characterized by the presence of a myeloid cells clone in peripheral blood in the absence of the sufficient reasons to diagnose the hematologic disease. The CHIP is proposed as a potential independent risk factor for vascular pathology. The aim of this study is to identify carriers of JAK2 V617F mutation among patients admitted for planned hospitalization at the Federal Center of Cardiovascular Surgery of Krasnoyarsk. Materials and methods. The study included 930 venous blood samples. JAK2 V617F mutation was detected by using the allele - specific real time polymerase chain reaction. Results. JAK2 V617F mutation was detected in 15 (1.6%) patients, but only two of them had blood cell count that could cause a hematological disease to be suspected. Conclusion. The inclusion of the JAK2 V617F mutation detection in the complex of laboratory tests of the cardiovascular patients can facilitate the timely identification of patients with increased thrombotic risk, as well as the timely diagnosis of myeloproliferative diseases.

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Coexistence of a Heterozygous JAK2(V617F) Mutation and a Secondary BCR-ABL Translocation within the Compartment of Committed Myeloid Progenitors in Chronic Idiopathic Myelofibrosis.

Blood ◽

10.1182/blood.v108.11.4871.4871 ◽

2006 ◽

Vol 108 (11) ◽

pp. 4871-4871

Author(s):

Martin Bornhaeuser ◽

Brigitte Mohr ◽

Uta Oelschlaegel ◽

Peter Bornhauser ◽

Swen Jacki ◽

...

Keyword(s):

Bone Marrow ◽

Philadelphia Chromosome ◽

Jak2 V617f ◽

Janus Kinase ◽

Jak2 V617f Mutation ◽

Idiopathic Myelofibrosis ◽

Jak2 Mutation ◽

V617f Mutation ◽

Chronic Idiopathic Myelofibrosis ◽

Philadelphia Chromosome Positive

Abstract Myeloproliferative disorders such as polycythemia vera (PV), essential thrombocytosis (ET) and chronic idiopathic myelofibrosis (CIMF) are clonal hematopoietic diseases with clinical similarities including the risk of transformation into acute myelogeneous leukemia. By definition, these diseases have been separated from Philadelphia chromosome positive (Ph+) CML requiring negativity for the BCR-ABL transcript in PCR studies of bone marrow or peripheral blood. Several groups independently discovered a gain of function mutation of the Janus kinase 2 (JAK2) gene in Ph-negative myeloproliferative diseases. This mutation has been associated with the proliferation of clonogenic progenitors independently of exogenous cytokine stimulation. A sixty-six year old male patient presented with moderate splenomegaly (3 cm under the costal marigin), mild anemia (11.3 g/dl), elevated lactate deyhdrogenase, an increased count of circulating CD34+ cells and a dry bone marrow aspirate. Marrow histology confirmed a prefibrotic stage of chronic idiopathic myelofibrosis (CIMF). Metaphase cytogenetics as well as BCR-ABL FISH were performed on samples from bone marrow, blood and sorted CD34+, CD3+, CD19+ and CD14+ cells from a steady-state back-up leukapheresis. The JAK2(V617F) mutation was confirmed by an allele-specific PCR assay. A screen for BCR-ABL was performed by FISH and PCR in sorted cells as well as in individual colonies (CFU-GM and CFU-E). Four Philadelphia-chromosome positive metaphases could be detected out of 86 derived from the autologous leukapheresis product harvested and cryopreserved as back-up shortly after diagnosis. The BCR-ABL translocation could be detected by fluorescence in-situ hybridisation (FISH) in 2/16 (12.5%) isolated granulocyte/macrophage colonies only whereas all erythroid colonies were negative. The JAK2 mutation was detectable in all clones and was enriched in CD34+ selected cells. The patient experienced progressive splenomegaly despite the achievement of a molecular response measured by quantitative BCR-ABL PCR after treatment with imatinib mesylate. Our in-vitro investigations suggest that the secondary BCR-ABL translocation within the myeloid compartment was of minor pathophysiological relevance in this patient with CIMF harbouring a heterozygous JAK2 mutation.

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