Several Somatic Mutations of JAK2 Exon 12 Are Found in Patients with a JAK2 (V617F)-Negative Myeloproliferative Disorder That Is Mainly Characterized by Erythrocytosis.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 263-263
Author(s):  
Daniela Pietra ◽  
Sai Li ◽  
Angela Brisci ◽  
Francesco Passamonti ◽  
Elisa Rumi ◽  
...  
Keyword(s):  
Somatic Mutations ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Myeloproliferative Disorders ◽  
Myeloproliferative Disorder ◽  
Clinical Onset ◽  
Normal White Blood Cell ◽  
Sporadic Cases ◽  
Serum Erythropoietin ◽  
Low Serum

Abstract About 95% of patients with polycythemia vera (PV) carry the unique V617F mutation in JAK2 exon 14, which encodes a portion of the JH2 auto-inhibitory domain of the Jak2 kinase. Mutations in exon 12 have been recently reported in JAK2 (V617F)-negative patients with PV or idiopathic erythrocytosis. We searched for exon 12 mutations in 168 patients with JAK2 (V617F)-negative myeloproliferative disorders. The 2001 WHO criteria were employed for diagnosis. Of the 168 patients studied, 47 had sporadic PV, 11 had familial PV, 75 had essential thrombocythemia (ET), and 35 had primary myelofibrosis (PM). Seventeen patients with PV, including 15/47 sporadic cases and 2/11 familial cases, were found to carry deletions (n=15) or duplications (n=2) of exon 12 in circulating granulocytes but not in T-lymphocytes. None of the 110 patients with ET or PM was found to be positive. Mutations were detected by sequencing, and were then confirmed by sub-cloning in bacteria in 7/17 cases. Four of the 8 mutations detected were novel, while the most frequent ones were N542–E543del and E543–D544del. Mutations spanned from base 1606 to 1640, and the two duplications modified the rest of the sequence by adding 33 bp. In terms of protein, deletions predicted aminoacid changes spanning from phenylalanine 537 to aspartic acid 544, while duplications predicted changes from phenylalanine 547 onwards within the JH2 pseudokinase domain. Three categories of molecular lesions were identified: those involving a K539L substitution; those involving the E543del; and aminoacid duplications involving a substitution of phenylalanine 547. At clinical onset, 16/17 (94%) patients carrying a JAK2 exon 12 mutation had low serum erythropoietin (Epo) levels, indicating a combination of absolute erythrocytosis and suppressed endogenous Epo production. Moreover, 12/17 patients had erythrocytosis associated with normal white blood cell and platelet counts, i.e., isolated erythrocytosis. This frequency (71%) was significantly higher than that observed in 92 patients diagnosed with JAK2 (V617F)-positive PV at the Department of Hematology, IRCCS Policlinico San Matteo, Pavia, Italy (P<0.001). Most of these latter patients, in fact, had erythrocytosis combined with leukocytosis (WBC>12 x 109/L) and/or thrombocytosis (PLT>400 x 109/L), and only 22% of them had isolated erythrocytosis. Both patients with familial PV carrying an exon 12 mutation had an affected sibling with JAK2 (V617F)-positive PV. While the former showed isolated erythrocytosis, their JAK2 (V617F)-positive siblings had also thrombocytosis. In conclusion: several somatic mutations of JAK2 exon 12 - mostly 6 bp deletions - can be found in patients with a myeloproliferative disorder that is mainly characterized by erythrocytosis associated with low serum Epo levels; a genetic predisposition to acquisition of different JAK2 mutations is inherited in families with myeloproliferative disorders, and the mutation type (exon 12 vs exon 14) contributes to determining their variable clinical phenotype.

Somatic mutations of JAK2 exon 12 in patients with JAK2 (V617F)-negative myeloproliferative disorders

Blood ◽  
2008 ◽  
Vol 111 (3) ◽  
pp. 1686-1689 ◽  
Author(s):  
Daniela Pietra ◽  
Sai Li ◽  
Angela Brisci ◽  
Francesco Passamonti ◽  
Elisa Rumi ◽  
...  
Keyword(s):  
Blood Cell ◽  
Genetic Predisposition ◽  
Somatic Mutations ◽  
Jak2 V617f ◽  
Myeloproliferative Disorders ◽  
Myeloproliferative Disorder ◽  
Familial Cases ◽  
Clinical Onset ◽  
Affected Sibling ◽  
Sporadic Cases

Abstract We searched for JAK2 exon 12 mutations in patients with JAK2 (V617F)-negative myeloproliferative disorders. Seventeen patients with polycythemia vera (PV), including 15 sporadic cases and 2 familial cases, carried deletions or duplications of exon 12 in circulating granulocytes but not in T lymphocytes. Two of the 8 mutations detected were novel, and the most frequent ones were N542-E543del and E543-D544del. Most patients with PV carrying an exon 12 mutation had isolated erythrocytosis at clinical onset, unlike patients with JAK2 (V617F)-positive PV, most of whom had also elevations in white blood cell and/or platelet counts. Both patients with familial PV carrying an exon 12 mutation had an affected sibling with JAK2 (V617F)-positive PV. Thus, several somatic mutations of JAK2 exon 12 can be found in a myeloproliferative disorder that is mainly characterized by erythrocytosis. Moreover, a genetic predisposition to acquisition of different JAK2 mutations is inherited in families with myeloproliferative disorders.

scholarly journals In-Frame Exon 9 CALR Deletions Co-Occur with Other Alterations in the JAK-STAT Pathway in Myeloproliferative Neoplasms

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4588-4588 ◽  
Author(s):  
Yongbao Wang ◽  
Albert K Ho ◽  
Qiulu Pan ◽  
Frederick Karl Racke ◽  
Dan Jones
Keyword(s):  
Mutation Analysis ◽  
Somatic Mutations ◽  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Point Mutations ◽  
Jak2 V617f ◽  
Illumina Miseq ◽  
Primary Myelofibrosis ◽  
Ensembl Database ◽  
Stat Pathway

Abstract Introduction: Mutations in the chaperone gene calreticulin (CALR) have been recently identified in essential thrombocythemia (ET) and primary myelofibrosis (PMF), and are essentially mutually exclusive with JAK2 or MPL mutations. Normal and mutant CALR proteins may differentially affect the subcellular trafficking of JAK-STAT signaling components. CALR mutations previously reported in ET and PMF have been +1 frameshift (fs) mutations localized to exon (E) 9 that generate a novel C-terminal protein sequence with a shift from acidic to basic residues. CALR E9 in-frame (IF) deletions have been recently rarely reported as polymorphisms such as TMP_ESP_19_13054686_13054688 and TMP_ESP_19_13054650_13054658 (Ensembl database entries). We sought to determine the frequency and associated clinical features of CALR with E9 IF alterations in samples submitted for suspicion of a myeloproliferative neoplasm (sMPN). We also assessed whether CALR IF alterations are differentially associated with +1fs mutations or with JAK2 V617For other somatic mutations in MPN-associated genes. Materials and Methods: CALR mutation analysis of E9 was performed on genomic DNA extracted from blood, bone marrow (BM) aspirate or fixed BM biopsy sections using a Sanger sequencing assay with an analytic sensitivity of at least 15%. E9 IF cases were further assessed and mutations quantified by an Ion torrent sequencing panel assessing CALR, CSF3R, JAK2 and MPL, a second panel containing ASXL1, EZH2, IDH1, IDH2, KRAS, NRAS and TET2 and an Illumina MiSeq extended panel with 20 additional MPN-associated genes. These assays had a sensitivity of approximately 5%. JAK2 V617Fmutations were quantitated using a pyrosequencing assay with an analytic sensitivity of 1%. Results: We assessed CALR E9 mutation status in 733 sMPN samples that were negative for JAK2 V617F mutation. 148 (20.1%) had typical +1fs mutations (95 type 1 and variants, 53 type 2 and variants); 2 (0.3%) had point mutations (E381A and D7373M); 7 (1.0%) had IF deletions including E381_A382>A, D397_D400>D (n =4), D400_K401>D and E405_V409>V. All E9 IF deletions were present at ~50% of reads. Clinical diagnoses were cytopenia/BM fibrosis, ET, thrombocytosis/anemia, and sMPN unspecified. Mutation analysis for 27 additional MPN-associated genes revealed mutations in 5/7 (71.4%) IF deletion cases including in MPL (W515L,40%; D163Y,12%), CSF3R (A470T 46%), ASXL1 (D954fs*26, 45%) and ZRSR2 (S449_R450dup, 27%). No additional mutations were found in the 2 cases with non-synonymous CALR point mutations/SNPs. In a parallel set of 76 MPN samples that had JAK2 V617F at varying levels, we noted 1 E9 IF deletion (D397_D400>D) in a sMPN case with 21.6% JAK2 V617F, and a typical +1fs mutation (K385fs*47) in a case with low (4.2%) JAK2 V617F. All other JAK2 V617F cases had no E9 CALR alterations. Conclusions: CALR E9 in-frame deletions occur in up to 1% of sMPN samples and involve a variety of codons in the acidic domain. Therefore, sizing assays without DNA sequencing are not sufficient to unequivocally distinguish IF deletions from the characteristic +1 frameshift somatic mutations associated with ET and PMF. Given their level, these CALR IF deletions are likely germline sequence variants but are associated with a high frequency of somatic mutations in other MPN-associated genes but not with CALR +1fs mutations. Their co-occurrence with pathogenic somatic mutations in JAK2, MPL and CSF3R affecting the JAK-STAT pathway raises the possibility for a contributory role of altered CALR proteins produced by these E9 deletions in the pathogenesis of MPN. Disclosures Wang: Quest Diagnostics: Employment. Ho:Quest Diagnostics: Employment. Pan:Quest Diagnostics: Employment. Racke:Quest Diagnostics: Employment. Jones:Quest Diagnostics: Employment.

Evaluation of the JAK2 V617F gene mutation in myeloproliferative neoplasms cases: a one-center study from Eastern Anatolia

2019 ◽  
Vol 44 (4) ◽  
pp. 492-498
Author(s):  
Gonca Gulbay ◽  
Elif Yesilada ◽  
Mehmet Ali Erkurt ◽  
Harika Gozukara Bag ◽  
Irfan Kuku ◽  
...  
Keyword(s):  
Blood Cell ◽  
Essential Thrombocythemia ◽  
Myeloproliferative Neoplasms ◽  
Hematological Parameters ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Myeloproliferative Disorders ◽  
Jak2 V617f Mutation ◽  
V617f Mutation ◽  
The Difference

AbstractObjectiveDetection ofJAK2V617F in myeloproliferative neoplasms (MPNs) is very important in both diagnosis and disease progression. In our study, we investigated the frequency ofJAK2V617F mutation in patients with myeloproliferative disorders.MethodsWe retrospectively reviewed the records of 720 patients (174 females and 546 males) who were tested for JAK2 V617F mutation from January 2007 to December 2017.ResultsIn our patients were determined 22.6%JAK2V617F mutation. 33.3% in women, 19.2% in men have been positive forJAK2V617F mutation. In our studyJAK2V617F present in 48.6% of essential thrombocythemia, 80.5% of polycythemia rubra vera (PV), 47.5% of primary myelofibrosis, 10% of MPNs, unclassifiable, 0.8% of others. We also investigated the difference in hematological parameters [white blood cell, hemoglobin (Hb), hematocrit (HCT), red blood cell distribution widths (RDW) and platelets count (PLT)] betweenJAK2V617F positive andJAK2V617F negative patients.ConclusionsInvestigation of the JAK2 V617F mutation is very important in cases of MPNs. In our study JAK2 V617F mutation was higher in PV, essential thrombocythemia, and primary myelofibrosis patients. However, there were significant differences in Hb, HCT, RDW and PLT levels in mutation-positive patients.

Validation of a Novel Clonality Assay in Patients with Clonal Hematologic Disorders

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3718-3718
Author(s):  
Neeraj Agarwal ◽  
Sabina Swierczek ◽  
Roberto Nussenzveig ◽  
Scott James Samuelson ◽  
Charles J. Parker ◽  
...  
Keyword(s):  
X Chromosome ◽  
Elderly Women ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Myeloproliferative Disorders ◽  
The Elderly ◽  
Hematopoietic Stem ◽  
Hematologic Disorders ◽  
Hematological Disorders ◽  
Clonal Hematopoiesis

Abstract Clonality assays, based on X-chromosome inactivation, discriminate active from inactive alleles. They are useful in the diagnosis and assessment of therapeutic response in clonal hematologic disorders, especially in absence of an identifiable somatic mutations. Skewing of X-chromosome allelic-usage, based on preferential methylation of one of the HUMARA alleles, was reported as evidence of clonal hematopoiesis in ~30% elderly women, precluding the use of this assay in elderly patient (>65 years of age). Using a quantitative, transcriptionally-based clonality assay, we did not detect clonal hematopoiesis in >200 healthy non-elderly women. In view of the susceptibility of aging hematopoietic stem cells to epigenetic dysregulation, we reinvestigated the issue of clonality in forty elderly women (age 65–92, mean 81.3 years), using a novel, quantitative qPCR transcriptional clonality assay. In this assay, mRNA transcribed from five X-chromosome polymorphic genes expressed in peripheral blood neutrophils is quantified by real time, allele specific RT-PCR. We did not detect clonal hematopoiesis in any of the elderly women. However, using HUMARA assay, 30% of these elderly women were detected to have monoallelic methylation of the HUMARA gene locus, consistent with previously reported literature. We concluded that our novel transcriptional clonality assay is suitable for evaluation of clonal hematopoiesis in all women including elderly women (Swierczek S, Agarwal N et al. Blood 2008, July 18 epub). Using this novel assay, we detected clonal hematopoiesis in 31 out of 32 well characterized patients with myeloproliferative disorders: polycythemia vera (all fourteen patients were clonal by our assay and all were JAK2V617F positive), essential thrombocytosis (nine out of ten patients were clonal by our assay, one out of ten patients was cMPLW515L positive, seven out of ten were JAK2 V617F positive; however one subject with low JAK2 V617F allelic burden was polyclonal by our assay), and primary myelofibrosis (all eight patients were clonal by our assay and two of them were positive for JAK2V617F). In addition, we detected clonal hematopoiesis in 4 patients with unexplained anemia (two eventually evolved in to myelodysplastic syndrome), and in one patient with persistent leukocytosis (eventually found to be cMPLW515L positive). Using our assay we did not detect clonal hematopoiesis in 10 patients with reactive or secondary erythrocytosis, thrombocytosis or leukocytosis. We conclude that our novel transcriptional clonality assay is suitable for detection of clonal hematopoiesis in patients with clonal hematologic disorders, especially in patients lacking known somatic mutation. Studies to detect an emerging clone in milieu of polyclonal hematopoiesis (such as seen in PNH or early stages of clonal hematological disorders) by comparison of X-chromosome allelic usage ratio in myeloid cells and in T lymphocytes are underway.

Molecular and clinical features of refractory anemia with ringed sideroblasts associated with marked thrombocytosis

Blood ◽  
2009 ◽  
Vol 114 (17) ◽  
pp. 3538-3545 ◽  
Author(s):  
Luca Malcovati ◽  
Matteo G. Della Porta ◽  
Daniela Pietra ◽  
Emanuela Boveri ◽  
Andrea Pellagatti ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Somatic Mutations ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Refractory Anemia ◽  
Ringed Sideroblasts ◽  
Myeloid Neoplasm ◽  
Normal Platelet ◽  
Cd34 Cells ◽  
Patient Groups

Abstract We studied patients with myeloid neoplasm associated with ringed sideroblasts and/or thrombocytosis. The combination of ringed sideroblasts 15% or greater and platelet count of 450 × 109/L or greater was found in 19 subjects fulfilling the diagnostic criteria for refractory anemia with ringed sideroblasts (RARS) associated with marked thrombocytosis (RARS-T), and in 3 patients with primary myelofibrosis. JAK2 and MPL mutations were detected in circulating granulocytes and bone marrow CD34+ cells, but not in T lymphocytes, from 11 of 19 patients with RARS-T. Three patients with RARS, who initially had low to normal platelet counts, progressed to RARS-T, and 2 of them acquired JAK2 (V617F) at this time. In female patients with RARS-T, granulocytes carrying JAK2 (V617F) represented only a fraction of clonal granulocytes as determined by X-chromosome inactivation patterns. RARS and RARS-T patient groups both consistently showed up-regulation of ALAS2 and down-regulation of ABCB7 in CD34+ cells, but several other genes were differentially expressed, including PSIP1 (LEDGF), CXCR4, and CDC2L5. These observations suggest that RARS-T is indeed a myeloid neoplasm with both myelodysplastic and myeloproliferative features at the molecular and clinical levels and that it may develop from RARS through the acquisition of somatic mutations of JAK2, MPL, or other as-yet-unknown genes.

Modulated Expression of BCL-xL and GATA-1 Genes Is a Common Feature in Myeloproliferative Disorders (MPD) Both in JAK2-V617F Positive and Negative Patients

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1533-1533
Author(s):  
Sarah Pozzi ◽  
Francesca Bertolotti ◽  
Silvio Parodi ◽  
Raffaella Ponassi ◽  
Barbara Biasotti ◽  
...  
Keyword(s):  
Mononuclear Cells ◽  
Statistical Significance ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Myeloproliferative Disorders ◽  
Expression Level ◽  
Jak2 V617f Mutation ◽  
Mutational Status ◽  
V617f Mutation

Abstract JAK2-V617F mutation has been identified in more than 90% of patients with Polycythemia Vera (PV) and in 50 to 60% of patients with Essential Thrombocythemia (ET) or Primary Myelofibrosis (PMF). The mutation has reinforced the original idea that ET, PV, and PMF have a common background; however, some key questions remain open: why, in JAK2-V617F patients, only a proportion of progenitors is bearing the mutation and the other is wild type (wt); why patients with the same mutation have a different disease; what have in common patients JAK2-V617F positive (mutated) and wt with the same disease. We observed that a new synthetic peptide (072RB) able to bind Bcl-xL molecule, exerting an apoptotic effect, inhibited the in vitro cord blood (CB) mononuclear cells (MNC) growth. Moreover, this effect correlated with a high expression level of Bcl-xL messenger (RQ-PCR). Since Bcl-xL was involved in erythropoiesis, we extended the expression studies to bone marrow (BM) MNC from16 PV (13/16 mutated),15 ET (9/15 mutated) and peripheral blood (PB) MNC from 18 PMF (9/18 mutated). JAK2 mutational status was assigned by allele-specific-PCR (AS-PCR). MNC from PV-BM and PMF-PB showed a Bcl-xL level of expression significantly higher than in MNC from healthy donors (NBM and NPB) both in mutated and in wt patients (PV: p=0.01 and p=0.004; PMF: p=0.005 and p=0.05 respectively). In ET, the expression level of Bcl-xL tended to be elevated compared to controls but did not reach the statistical significance. Since other factors can modulate Bcl-xL expression independently from the constitutive activation of JAK2/STATs pathway induced by JAK2-mutated, we analysed GATA-1 gene, a transcription factor that binds the Bcl-xL promoter and that is involved in erythropoiesis and megakariocytopoiesis. We observed that GATA-1 was highly expressed in PV-BM and PMF-PB MNC both in mutated and in wt patients (PV: p=0.01 and p=0.05; PMF: p=0.001 and p=0.03). In ET-BM MNC, GATA-1 followed the Bcl-xL pattern of expression. The highest messengers levels were observed PMF-PB MNC and CB MNC that, after in vitro 072RB peptide treatments, showed a 25%–50% of cells growth inhibition with respect to untreated controls. The protein expression was confirmed by cytofluorimetric analyses. Our finding may indeed be compatible with reduced apoptosis both in mutated and wt patients. Thus, the elevated expression levels of Bcl-xL and GATA-1 genes may represent a common feature in MPD, independent from the presence of the JAK2-V617F mutation and supports the hypothesis of a “phenotypic continuum” in MPD. It is noteworthy that in patients bearing the mutation, a variable proportion of hematopoietic progenitors in PV, ET and PMF have been documented to be wt. In this context, our findings may explain why wt hematopoiesis is not overtaken by the mutated counterpart. These results could open a new insight in the field of MPD molecular characterization and may lead to new therapeutic approaches.

The Analysis of JAK2 and MPL Mutation as Well as JAK2 SNPs in MPN Patients by MassARRAY Assay.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4989-4989
Author(s):  
Su-Jiang Zhang ◽  
Hongxia Qiu ◽  
Jianyong Li
Keyword(s):  
Conflicts Of Interest ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Myeloproliferative Disorders ◽  
Molecular Pathogenesis ◽  
Significant Difference ◽  
Positive Rate ◽  
Allele Specific ◽  
Polymerase Chain ◽  
Distribution Frequency

Abstract Abstract 4989 Introduction Recent studies have shown that JAK2 V617F, MPL W515L/K and JAK2 exon 12 mutations underlie the major molecular pathogenesis of myeloproliferative disorders (MPN). Methods To ascertain the real prevalence of these mutations and the influence of genetic susceptibility in Chinese MPN patients, we applied Allele-Specific Polymerase Chain Reaction (AS-PCR), directly sequencing and MassARRAY assay into our study. Results The positive rate of JAK2 V617F in polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF) was 82.0%, 36.6% and 51.1% individually. We also found one ET patient, two PMF patients harboring MPL W515L mutation, and three PV patients harboring JAK2 exon 12 mutations. All of these patients were confirmed as JAK2 V617F negative. Moreover, clinical data demonstrated that PV patients with JAK2 exon 12 mutations had higher hemoglobin and lower age as well as WBC than PV patients with JAK2 V617F. In addition, through analysis of 4 polymorphic loci of JAK2 gene, no significant difference of distribution frequency was found among PV, ET and PMF patients. Distribution frequency of haplotype was not found to have significant difference among PV, ET and PMF patients either. Conclusion We conclude that JAK2 V617F is major molecular pathogenesis in Chinese MPN patients. MPL W515L mutation and JAK2 exon 12 mutations can also be found in JAK2 V617F negative MPN patients. Disclosures No relevant conflicts of interest to declare.

scholarly journals TET2 rs1548483 SNP Associating with Susceptibility to Molecularly Annotated Polycythemia Vera and Primary Myelofibrosis

2020 ◽  
Vol 10 (4) ◽  
pp. 259
Author(s):  
Diana L. Lighezan ◽  
Anca S. Bojan ◽  
Mihaela Iancu ◽  
Raluca M. Pop ◽  
Ștefana Gligor-Popa ◽  
...  
Keyword(s):  
Polycythemia Vera ◽  
Myeloid Leukemia ◽  
Somatic Mutations ◽  
Myeloproliferative Neoplasms ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
P Value ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide

Background: The complexity of myeloproliferative neoplasms (MPNs) cannot be characterized by acquired somatic mutations alone. Individual genetic background is thought to contribute to the development of MPNs. The aim of our study was to assess the association between the TET2 rs1548483 single nucleotide polymorphism (SNP) and the susceptibility to polycythemia vera (PV), essential thrombocythemia (ET), primary myelofibrosis (PMF) or chronic myeloid leukemia (CML). Methods: We evaluated the TET2 rs1548483 SNP through real-time PCR in 1601 MPN patients out of which 431 with PV, 688 with TE, 233 with PMF, 249 with CML and 197 controls. We included only patients with a molecularly proven driver mutation, such as JAK2 V617F, CALR or BCR-ABL1. Results: Significant association between TET2 rs154843 variant allele and JAK2 V617F-positive PV and PMF (OR = 1.70; 95% CI: 1.01–2.91; p-value = 0.046, and OR = 2.04; 95% CI: 1.10–3.77; p-value = 0.024, respectively), and type 2 CALR-positive PMF (OR = 2.98; 95% CI: 1.12–7.93; p-value = 0.035) was noted. Conclusions: The TET2 rs1548483 SNP is associated with the susceptibility to molecularly annotated PV and PMF.

scholarly journals A Case of Erythrocytosis in a Patient Treated with an Aromatase Inhibitor for Breast Cancer

2013 ◽  
Vol 2013 ◽  
pp. 1-3 ◽  
Author(s):  
Abhinav Iyengar ◽  
Dawn Sheppard
Keyword(s):  
Breast Cancer ◽  
Ductal Carcinoma ◽  
Jak2 V617f ◽  
Myeloproliferative Disorder ◽  
Pulmonary Diseases ◽  
Molecular Testing ◽  
Carcinoma Of The Breast ◽  
Obstructive Sleep ◽  
Serum Erythropoietin ◽  
Secondary Causes

A previously healthy 79-year-old female was referred to hematology for further evaluation of erythrocytosis. Two years earlier she had been diagnosed with ER/PR-positive ductal carcinoma of the breast and was receiving hormonal therapy with exemestane. No secondary cause of erythrocytosis was identified. Serum erythropoietin (EPO) level was normal, and molecular testing for the JAK2 V617F and exon 12 mutations was negative. A bone marrow biopsy showed a mild increase in erythropoiesis, and no spontaneous erythroid colonies were demonstrated. Erythrocytosis is common reason for referral to a hematologist. The myeloproliferative disorder, polycythemia vera, and the rare congenital polycythemias represent primary erythrocytosis. Common secondary causes include smoking, obstructive sleep apnea, and other pulmonary diseases. Erythrocytosis is well described with certain classes of drugs, including androgens. We hypothesize that exemestane contributed to the development of erythrocytosis in our patient. To our knowledge, erythrocytosis has not been previously described in association with aromatase inhibitors. These drugs prevent the conversion of androstenedione and testosterone to estrogen; thus the physiologic mechanisms may be similar to those responsible for erythrocytosis seen with exogenous androgens. These mechanisms are not well understood, but may include altered iron metabolism by a reduction in hepcidin levels.

A High Sensitivity Detection Technique Reveals JAK2-V617F Mutation in Additional 20% of Patients with Essential Thrombocytemia, but Not in Patients with Primary Myelofibrosis, Considered Negative with a Conventional ASO-PCR

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2801-2801
Author(s):  
Francesca Bertolotti ◽  
Sarah Pozzi ◽  
Massimo Ulivi ◽  
Marina Podestà ◽  
Davide Imperiale ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
High Sensitivity ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Myeloproliferative Disorders ◽  
Jak2 V617f Mutation ◽  
The Real ◽  
V617f Mutation

Abstract Polycytemia Vera (PV), Essential Thrombocytemia (ET) and Primary Myelofibrosis (PMF) are defined as the major Philadelphia-negative myeloproliferative disorders (MPD). The JAK2-V617F gene mutation is a common feature of MPD but it is present in a variable proportion in patients: 95% of PV, 23 to 57% of ET and 30 to 57% of PMF patients. At the present, the most important role of JAK2-V617F mutation testing, over all during the initial evaluation of MPD patients, is that it can definitively confirm the diagnosis. In fact, its specificity permits to discriminate the considerable clinical overlap between reactive cellular proliferations and clonal myeloproliferative disorders. Moreover, because V617F is an acquired mutation that can be present in a small proportion of granulocytic populations, especially for ET, a highly sensitive detection method is essential. In fact, phenotypic effects ascribed to the presence of the JAK2-V617F mutation have been reported over all in studies with ET patients. Different sensitivity of various assays methods partially accounts for the wide range of mutation frequencies reported in literature for ET and PMF. Thus, to try to increase the sensitivity of JAK2 mutational status detection, we developed a Real-Time PCR technique that enhances allele discrimination between mutant and wild-type sequence. A Locked Nucleic Acid (LNA) clamping oligomer was added to the PCR reaction solution. In this macromolecules, the ribose moiety is modified with an extra bridge connecting the 2′ and 4′ carbons. The bridge “locks” the ribose in the 3′-end structural conformation. It binds preferentially the JAK2 wild type sequence preventing from polymerase elongation. The melting curve was used to analyse amplification products, avoiding post-PCR processing and supplying the diagnostic information immediately at the end of the amplification. 236 genomic DNA samples from healthy donors, ET and PMF patients were tested for JAK2-V617F mutation detection with a conventional allelespecific PCR (ASO-PCR, sensitivity: 1–3%). All samples were re-evaluated with a seminested PCR protocol and Real-Time PCR based method in order to improve the sensitivity. The cell line HEL DNA dilutions were used to assess the semi-nested PCR and the Real-Time PCR assay sensitivity level (0,1%). The frequency of JAK2-V617F point mutation increased from 52 to 72% in 168 ET samples. All results obtained with the new technique were confirmed by the semi-nested PCR protocol. In 58 PMF samples tested, 50% of patients were positive for the mutation in ASO-PCR while 55% resulted positive with the semi-nested protocol confirmed by the Real-Time PCR test. The high sensitivity in the JAK2-V617F mutation detection obtained with the semi-nested and the Real-Time PCR revealed that 20% of patients affected by ET and considered JAK2-V617F negative with a conventional ASO-PCR, were effectively positive. The comparison between three different analytical methods revealed that in ET but not in PMF patients, the mutation can be present only in a small proportion of granulocytic populations. Thus, since the prognostic relevance of V617F allele in ET, unlike in PMF, seems to be relevant, our high sensitive detection protocol can be effective for a correct molecular characterization and a diagnostic classification. The finding that a large proportion of ET patients bears a very small amount of JAK2-V617F mutated hematopoiesis further emphasizes the problem of the role of this small clone and warrants longitudinal analysis to understand whether this proportion remains stable or expands over time.

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