Cases Of Polycythemia Vera Research Articles

Clinical Analysis of Driver Mutations in Patients with Ph Negative Myeloproliferative Neoplasms

To explore the relationship between driver mutations and clinical characteristics in patients with Philadelphia chromosome (Ph) negative myeloproliferative neoplasms (MPN), so as to provide evidence for diagno-sis and treatment of the disease. The clinical data of 410 patients with classic Ph negative MPN including 150 cases of polycythemia vera (PV), 188 cases of essential thrombocythemia (ET) and 72 cases of primary myelofibrosis (PMF) from January 2013 to December 2016 in Fujian Medical University Union Hospital were retrospectively analyzed. The PCR or DNA sequencing were used for JAK2 V617F, JAK2 exon12, CALR and MPL W515L/K mutation analyses, and follow-up information on patients was updated by direct phone call or follow-up in outpatient. Among the 410 patients with Ph negative MPN, 136 (33.2%) cases were asymptomatic at diagnosis. 389 cases were sequenced and JAK2 V617F was detected in 87.1% (122/140) of PV, 64.1% (118/184) of ET, 64.6% (42/65) of PMF; JAK2 exon 12 mutation in 1 case of PV; MPL W515L/K mutation in 1 case of ET and PMF, respectively; CALR mutation in 18(9.8%) cases of ET and 5 (7.7%) cases of PMF. JAK2 V617F mutated PV patients ocourred in older age: the white blood cell count, platelet count and incidence of splenomegaly were higher than JAK2-negative PV cases(P<0.05). Compared with JAK2 V617F mutated ET patients, CALR mutated ET cases displayed younger age, lower leukocyte count, higher platelet count and lower incidence of thrombosis; JAK2-negative ET cases had younger age, lower leukocyte count, lower hemoglobin level, higher platelet count and lower incidence of thrombosis(P<0.05). The incidence of splenomegaly in JAK2 V617F or CALR mutated PMF patients was both higher than that in JAK2-negative PMF cases, but the incidence of leukemia transformation in JAK2-negative PMF patients was higher than that in JAK2 V617F mutated cases (P<0.05). The types of driver mutations are closely related with the clinical features and prognosis in Ph- negative MPN patients.

Molecular genetics of BCR-ABL1 negative myeloproliferative neoplasms in India.

Over the past decade, we have moved on from a predominantly morphological and clinical classification of myeloproliferative neoplasms (MPN) to a more evolved classification that accounts for the molecular heterogeneity that is unique to this subgroup of hematological malignancies. This usually incorporates mutations in Janus kinase 2 (JAK2), MPL, and calreticulin (CALR) genes. In this manuscript, we report the frequency of these mutations in a cohort of Indian patients at a tertiary cancer center. One hundred and thirty cases of MPN were included in this study. These cases were diagnosed and classified based on the World Health Organization 2008 criteria. JAK2 and MPL mutations were detected using high sensitivity allele-specific polymerase chain reaction using fluorescent labeled primers followed by capillary electrophoresis. A subset of JAK2 and CALR mutations were assessed using a fragment length assay. Among the MPN, we had 20 cases of polycythemia vera (PV), 34 cases of essential thrombocythemia (ET), and 59 of myelofibrosis (MF). JAK2, MPL, and CALR mutations were mutually exclusive of each other. Seventeen cases were categorized as MPN unclassifiable (MPN-U). JAK2p.V617F and MPL mutations were present in 60% (78 of 130) and 5.3% (7 of 130) of all MPN. All the PV cases harbored the JAK2 p.V617F mutation. A total of 23.8% (31 of 130) of patients harbored CALR mutations. CALR exon 9 mutations were detected in 60.8% (14 of 23) and 50% (5 of 10) of JAK2 and MPL negative MF and ET cases, respectively. MPN-U cases included three JAK2 p.V617F positive, two MPL p.W515 L, and 12 CALR positive cases. Ten different types of CALR indels (8 deletions and 2 insertions) were detected of which Type I and Type II mutations were the most common, occurring at a frequency of 45.1% (14 of 31) and 22.5% (7 of 31), respectively. We report frequencies of JAK2 p. V617F, MPL exon 10 and CALR mutations in 130 patients similar to those reported in western literature. These mutations carry not only diagnostic but also prognostic relevance.

Polycythemia Vera (PV) Complicated by Late Diagnosis of Multiple Splenic Infarcts: A Case Report

Polycythemia vera (PV) is a chronic myeloproliferative tumor where bone marrow makes more red blood cells and other bone marrow cells. Many patients initially are asymptomatic, however, other patients may develop symptoms and complications of this disease later on. One of the PV complications is developing thrombosis in different sites, one of these sites is splenic vessels causing splenic infarction. Here we are describing a JAK2 positive PV case who presented with vague abdominal pain and diagnosed by CT to have splenic infarction, and was treated medically without going to surgical options. In conclusion, splenic infarction is a rare and unique complication of PV. Early diagnosis is paramount to prevent complications and a team approach is highly recommended for the best outcomes.

JAK2 V617F hematopoietic clones are present several years prior to MPN diagnosis and follow different expansion kinetics.

TO THE EDITOR: The JAK2 V617F mutation is the most common somatic mutation in the classical myeloproliferative neoplasms (MPNs), present in >95% of cases of polycythemia vera (PV) and ∼50% of essential thrombocythemia (ET) and myelofibrosis (MF).[1][1][⇓][2][⇓][3]-[4][4] It is usually the

Kidney transplantation in a patient with polycythemia vera

Polycythemia vera (PV) is a clonal over proliferation of hematopoietic stem cells, which increases red blood cell (RBC) mass and hematocrit, and is frequently accompanied with leukocytosis, thrombocytosis, or both. Few cases of renal involvement of PV have been reported to date. We present a case of PV based on JAK2 (Janus kinase 2) mutation that did not need any treatment after unrelated kidney transplantation. According to the rarity of kidney transplantation in PV, more clinical evidence is needed to determine the frequency of its improvement after transplantation

Sequencing myeloproliferative leukemia exon 10 mutations in iranian patients with breakpoint cluster region-abelson murine leukemia viral oncogene homolog 1-negative myeloproliferative neoplasm

Context: Breakpoint cluster region-Abelson murine leukemia viral oncogene homolog 1 (BCR-ABL1)-negative myeloproliferative neoplasms (MPNs), including essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF), are distinguished by the dysregulated Janus kinase (JAK)-signal transducer and activator of transcription functionality, abnormal hematopoiesis, and spontaneous proliferation. Moreover, a mutation in JAK2V617F as well as myeloproliferative leukemia (MPL) mutations have been reported in these patients, which could be important in the pathogenesis of diseases. MPL plays a role in the development of megakaryocytes and platelets as well as self-renewal of hematopoietic stem cells. Aims: The aim of the present study was to investigate the frequency of MPL mutations in patients with BCR-ABL1-negative MPNs. Settings and Design: This study was a cross-sectional study conducted as an analytical, descriptive review. Subjects and Methods: This study was performed on 54 newly diagnosed patients with BCR-ABL1-negative MPN (PV, ET, and PMF) who referred to Shafa Hospital, Ahvaz, Iran. Five milliliter whole blood was drawn from these patients; JAK2V617Fmutation and mutations in exon 10 of MPL gene were investigated using polymerase chain reaction and DNA sequencing techniques following the isolation of mononuclear cells from the blood.Statistical Analysis: All the data were presented as mean ± standard deviation and were analyzed by SPSS. Results: JAK2V617Fmutation was present in 33 patients, among whom there were 6 ET (35.3%), 7 PMF (41.2%), and 20 PV cases (100%). MPLW515 L/Kmutation was found in only one case of PMF, which was negative for JAK2V617Fmutation. The prevalence of these mutations was 1.8%, and the patient had splenomegaly with lower white blood cell counts and hemoglobin concentration than normal. Conclusions: Based on the results, MPL mutations rarely occur in patients with MPN. These mutations could be co-expressed with JAK2 mutations and might be helpful for detecting MPN patients with no BCR-ABL1 translocation or JAK2V617Fmutation.

Allogeneic Hematopoietic Cell Transplantation for Leukemic Transformation Preceded by Philadelphia Chromosome–Negative Myeloproliferative Neoplasms: A Nationwide Survey by the Adult Acute Myeloid Leukemia Working Group of the Japan Society for Hematopoietic Cell Transplantation

To clarify the outcome of allogeneic hematopoietic cell transplantation (HCT) for leukemic transformation (LT) preceded by Philadelphia chromosome–negative (Ph-neg) myeloproliferative neoplasms (MPNs), we conducted a retrospective study using the national registry database of the Japan Society for Hematopoietic Cell Transplantation. From 2000 to 2013, 39 patients underwent their first allogeneic HCT with related bone marrow or peripheral blood stem cells (n = 8), unrelated bone marrow (n = 15), and unrelated umbilical cord blood (n = 16). The median patient age was 57 years. The underlying Ph-neg MPNs included 21 cases of essential thrombocythemia, 11 cases of primary myelofibrosis, and 7 cases of polycythemia vera. The median interval between the diagnosis of LT and transplantation was 134 days. Thirty-two cases (82%) were not in remission at the time of transplantation. The 2-year overall survival rate was 29.2% (95% confidence interval [CI], 15.5% to 44.3%). The median follow-up of the surviving patients was 1989.5 days (range, 285 to 3270). The cumulative incidences of relapse and nonrelapse mortality at 2 years were 34.4% (95% CI, 19.6% to 49.8%) and 34.2% (95% CI, 19.6% to 49.4%), respectively. The study results suggested that allogeneic HCT provides long-term survival in approximately one-third of patients with LT preceded by Ph-neg MPNs.

Detection of JAK2 Exon 12 Mutations in JAK2 V617F-Negative Polycythemia Vera Patients by Cloning Technique

Introduction: The identification of mutations of the JAK2 gene is a useful marker in the diagnosis of polycythemia vera (PV) patients. We studied the frequency of JAK2 mutations in a group of PV patients because data are still very limited regarding this subject in Polish patients. Methods: The JAK2 V617F mutation was examined using the amplification refractory mutation system (ARMS)-PCR method. Direct sequencing and a cloning technique were performed to determine alternations in exon 12 of the JAK2 gene. Results: A group of 90 consecutive patients with a suspected diagnosis of polycythemia vera were investigated. In 91% of the cases, the JAK2 V617F mutation was identified. The remaining JAK2 V617F-negative patients were subjected to examination for JAK2 exon 12 by direct PCR product sequencing and the cloning technique. The following mutations were identified: H538-K539delinsL, E543-D544del and N542-E543del. These exon 12 mutants constituted 50% of PV JAK2 V617F-negative group and 4.4% (out of 90) of all PV patients (JAK2 V617F-positive and JAK2 V617F-negative). Conclusion: Our results demonstrate the prevalence of JAK2 mutations (V617F and in exon 12) in PV cases. Moreover, the data show that direct sequencing is not an adequate technique for exon 12 mutation identification; therefore, appropriate methodology should be considered for using this molecular marker in the process of diagnosis.

Coexisting JAK2V617F and CALR Exon 9 Mutations in Myeloproliferative Neoplasms - Do They Designate a New Subtype?

The classic BCR-ABL1-negative myeloproliferative neoplasm is an operational sub-category of MPNs that includes polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). The JAK2V617F mutation is found in ~ 95% of PV and 50-60% of ET or PMF. In most of the remaining JAK2V617F- negative PV cases, JAK2 exon 12 mutations are present. Amongst the JAK2V617F-negative ET or PMF 5-10% of patients carry mutations in the MPL gene. Prior to 2013, there was no specific molecular marker described in the remaining 30-40% ET and PMF. In December 2013, two research groups independently reported mutations in the gene CALR found specifically in ET (67-71%) and PMF (56-88%) but not in PV. Initially CALR mutations were reported mutually exclusive with JAK2 or MPL. However, co-occurrence of CALR mutations with JAK2V617F has been reported recently in a few MPN cases. Many studies have reported important diagnostic and prognostic significance of CALR mutations in ET and PMF patients and CALR mutation screening has been proposed to be incorporated into WHO diagnostic criteria for MPN. It is suggestive in diagnostic workup of MPN that CALR mutations should not be studied in MPN patients who carry JAK2 or MPL mutations. However JAK2V617F and CALR positive patients might have a different phenotype and clinical course, distinct from the JAK2-positive or CALR-positive subgroups and identification of the true frequency of these patients may be an important factor for defining the prognosis, risk factors and outcomes for MPN patients.

Hairy cell leukemia followed by polycythemia vera: report of the first case.

Hairy cell leukemia followed by polycythemia vera: report of the first case.

Clinical and Haematological Features of Genetic Mutations in MPN Patients with Diagnosis of Prefibrotic Idiopathic Myelofibrosis (MF0)

Background: Diagnosis of a prefibrotic state (MF0) presents histological diagnostic difficulties. MF0 has a worst prognostic impact than Essential Thrombocythemia (TE) as regard the thrombotic risk and a higher risk towards Idiopathic Myelofibrosis (MI) and acute leukemia evolution. For this reason it is very useful to identify this group of patients.Aims: The aim of this study was to evaluate clinical and hematological impact of the mutational status in patients with an MF0 diagnosis.Methods: A retrospective chart review was performed from January 2010 to July 2015 in a single center in 317 patients affected by Ph negative chronic myeloproliferative neoplasms. Polycythemia vera cases were excluded. Thirty-three patients have been classified as MF0 on the base of the bone marrow histological examination. Onset features include cytogenetics, blood counts, peripheral CD34-positive cells, spleen and liver size, thrombotic events (prior to and post-diagnosis) and thrombotic risk. Fragment analysis was performed to study exon 9 CALR mutation, Real-time PCR was applied for exon 14 JAK2 V617F mutation and Sanger sequencing was used to identify exon 10 MPL mutations for 505 and 515 codons. According to genetic results, patients were identified into four groups according to a positivity for JAK2, MPL, CALR and for triple negativity.Results: The 33 patients with MF0 were: 11 (33%) JAK2 positive, 10 (30%) CALR positive, (10) 30% triple negative and 2 (7%) MPL positive. The latter group was not further considered for analysis due to the low number of cases. Eighty percent of CALR positive patients had a deletion on the exon 9 of the gene (8 del52bp and 2 del46bp), while 20% had the type 2 mutation (ins5bp). The average of JAK2 allelic burden was 20%. The 3 groups of patients were comparable for age, white blood counts and hemoglobin values. There was a female prevalence (23 vs 10 males). Platelet count was higher (median 875.500 103 µl, interquartile range 303.000 103 µl , p = 0.008) in CALR positive patients compared to JAK2 positive (median 569.000 103 µl, interquartile range 433.000 103 µl) and to triple negative patients (median PLT count 629.500 103 µl, interquartile range 378.250 103 µl). Noteworthy, bone marrow cytogenetic exam was normal in all patients. JAK2 positive patients had a larger spleen compared to the other two groups. Pre-diagnosis thrombotic events were exclusive for JAK2 positive patients and absent in the other groups. Triple negative patients do not have a negative prognostic impact for the thrombotic risk.Conclusions: CALR deletion could be considered as an MF0 marker and should be included in diagnostic work-up. JAK2 positivity in MF0 is associated with a high thrombotic risk. DisclosuresNo relevant conflicts of interest to declare.

The JAK2V617F Stem Cell Burden Is Mosaic, Dynamic and Correlates with Clinical Disease Burden in the MPN: An Exploitable Target

Introduction:Essential thrombocytosis (ET), polycythemia vera (PV), and myelofibrosis (MF; post ETMF, post PVMF and primary MF) share the JAK2V617F mutation, but differ with regard to clinical phenotype, rate of disease progression, and risk of transformation. Variation in the JAK2V617F neutrophil allele burden does not account for these observed differences in clinical behavior or natural history. We therefore investigated the JAK2V617F burden and JAK2 genotype composition in the hematopoietic stem cell (HSC) population of MPN patients.Methods:We studied 47 JAK2V617F-positive MPN patients during 51 distinct disease phases. Circulating CD34+ cells were flow-sorted based on the stem cell markers CD34, CD38 and aldehyde dehydrogenase (ALDH). CD34+ CD38- ALDH+ HSC were sorted into 96 well plates and single cell JAK2 genotypes (average 40 single cells genotyped/patient with >1000 total single cells genotyped) were obtained using a nested PCR assay. Additional genomic lesions and chromosomal copy number variation were investigated in the sorted, single cell fractions in informative patients by FISH or multiplex single cell PCR. Distribution of JAK2V617F stem cell genotypes were correlated with disease phenotype, neutrophil JAK2V617F allele burden, splenomegaly, white cell count, chemotherapy requirement and disease evolution.Results:In all MPN cases, regardless of disease class, the JAK2V617F mutation was detected in the CD34+ CD38- ALDH+ fraction - the same population in which normal HSC reside. All ET and MF patients, and the majority of PV patients, had three JAK2 genotypes coexisting in their respective HSC populations. ET was characterized by a high percentage of JAK2WT stem cells (>75%) despite the concomitant presence of JAK2V617F homozygous clones and disease durations >15 years. Importantly, in the ET patients where JAK2WT clones fell to less than 50%, a PV phase followed. MF was characterized by a relatively low percentage of JAK2WT stem cells (median 24%), regardless of disease duration. PV had the most variable JAK2 genotypes with a wide range of JAK2WT stem cells (4%-92%) and a wide range of JAK2V617F homozygous stem cells (2-100%), and in 5/16 PV cases, only JAK2WT and JAK2V617F homozygous stem cells were identified.PV patients with JAK2V617F homozygous clones comprising more than 50% of their stem cells, regardless of disease duration, had higher white cell counts, higher neutrophil allele burdens, larger spleens and higher prevalence of chemotherapy compared to PV patients who had less than 50% JAK2V617F homozygous HSCs. The percentage of JAK2V617F homozygous HSC did not correlate with disease duration: some PV patients with a disease duration of >18 years had less than 10 % JAK2V617F homozygous HSC.A JAK2V617F - positive PV patient with a high JAK2V617F HSC burden and a high neutrophil JAK2V617F burden transformed to a JAK2V617F-negative chronic myelomonocytic leukemia (CMMoL); at the time of HSC analysis, the neutrophil JAK2V617F allele burden was 0% (previously 90%) and the HSC JAK2V617F homozygous percentage fell to 3% (previously 60%). While this patient's CMMoL was molecularly undefined, lesions identified in other JAK2V617F-positive patients (including mutations of ASXL1, TET2, deletion of 5q, 7q and 11q, trisomy 8 and 9), were also found in the CD34+ CD38- ALDH+ HSCs using single cell techniques, sometime coexistent with JAK2V617F-positive HSC, and sometimes in JAK2WT HSC.Conclusion:Driver and progression lesions in the JAK2V617F-positive MPN are acquired at the primitive HSC level. Despite decades of disease, the HSC pool in the MPN is mosaic for acquired lesions and also retains JAK2WT clones. Dominance of a particular JAK2 genotype at the primitive HSC level is variable, and distinguishes ET, where JAK2WT stem cells outnumber JAK2V617F-positive HSC, from MF, where JAK2WT HSC are the minority. PV is the most variable of the three MPN with regard to JAK2 genotype mosaicism. The allelic burden of HSC JAK2V617F in PV correlates with clinical disease burden. However, neither time nor JAK2V617F genotype determines the HSC burden in ET and PV, indicating that an undefined factor is a modifier of this important disease-defining process. Understanding the biology of HSC JAK2V617F homozygous clonal dominance may define an exploitable target to control disease burden, and to mitigate disease progression and evolution. DisclosuresMoliterno:incyte: Membership on an entity's Board of Directors or advisory committees. Spivak:Incyte: Membership on an entity's Board of Directors or advisory committees.

Profile of Calreticulin (CALR) Somatic Mutations in a Cohort of Pakistani Patients with Myeloproliferative Neoplasms

Introduction:Calreticulin (CALR) is a calcium binding multifunctional protein encoded by the CALR gene, whose job is to bind to mis-folded proteins and prevent them from being exported from the endoplasmic reticulum to the golgi apparatus. Outside the endoplasmic reticulum it is found both intra- and extracellularly on the cell surface and has been implicated in diverse processes including proliferation, apoptosis, phagocytosis and immunogenic cell death.In December 2013, somatic mutations in exon 9 of CALR were identified as the second most prevalent acquired nucleotide changes in JAK2 mutation negative essential thrombocythosis (ET) and primary myelofibrosis (PMF) patients but not in polycythaemia vera (PV) patients. At that time CALR mutations were found mutually exclusive with JAK2 and MPL. Recently there have been some reports on co-occurence of JAK2 and CALR mutations, not only in ET and PMF but also in some PV cases. Indels in CALR have also been reported in a JAK2 mutation negative PV patient. All CALR mutations are insertions or deletions resulting in a frameshift and cluster in exon 9 which is the last exon of the gene. Thus far, more than 50 different types of mutations in CALR have been reported. Two specific mutations, Type I (52bp deletion) and Type II (5bp insertion), are most prevalent. Overall, these two mutation types are found in more than 80% of patients with mutant CALR. One report found absence of Type II mutations and scatter point mutations in PMF patients of India. In the light of currently available literature, reported from North America (USA), Europe (Cyprus/Italy/Spain), Eastern Europe (Poland), and East Asia (Mainland China/Taiwan China), indel mutations in CALR exon 9 occur with a similar frequency in both ET and PMF patients regardless of ethnic diversity. CALR mutations have been shown to have important diagnostic and prognostic significance in ET and PMF patients and will likely be incorporated into the World Health Organization diagnostic criteria for MPN.Methods:Clinical and hematological features were obtained from 51 MPN patients. We studied 10 patients with PV, 17 patients with ET, 12 patients with MF and 9 patients with Undifferentiated MPN. JAK2 V617F mutation was analyzed by DNA tetra-primer amplification refractory mutation system (ARMS-PCR). CALR mutations were identified by bi-directional Sanger sequencing.Results:In our cohort, CALR mutations were detected in 7 patients (13.7%; 7/51) of which one patients was positive for JAK2 V617F as well. All those who showed positive results for CALR mutations were ET patients (41.17%; 7/17). Type I mutation was found in 3 patients (42.8%; 3/7) and among them 2 had two new scattered point mutations (c.1081C>G and c.1086C>G) as well, Type II in 2 patients (28.5%; 2/7), and others in 2 patients (28.5%; 2/7). Among those 2 patients with CALR mutations other than Type I or Type II, one had novel CALR mutation pattern of 10bp deletion (c.1130_1139del) whereas other had reported CALR 12bp deletion (c.1214_1225del) profile.When CALR positive ET patients were statistically compared with JAK2 V617F positive patient, insignificant differences were found in platelet counts (p-value 0.198) and hemoglobin level (p-value 0.380) which might be due to the fact that there was only one JAK2 V617F positive patient in the cohort. No differences were also observed in hemoglobin, white blood cell, platelet counts, hepatomegaly, and splenomegaly between CALR positive and CALR negative patients (p-value >0.05).Conclusion:In our cohort of 51 MPN patients CALR mutations were found associated with ET only that is different from other studies worldwide. Prevalence of both scatter point and Type I and Type II CALR mutations are in agreement with worldwide studies but differ from the study conducted on Indian population which shows the need to conduct studies with large sample size in this region to explore the CALR mutation profile in the patients of MPN here. DisclosuresNo relevant conflicts of interest to declare.

Targeted Sequencing Reveals a Relationship Between Mutational Burden and Clinical Phenotype in MPNs

The Philadelphia-chromosome negative myeloproliferative neoplasms (MPNs) Essential Thrombocytosis (ET), Polycythemia Vera (PV), and Myelofibrosis (MF) are characterized by mutations, which drive JAK-STAT pathway activation. Several studies have demonstrated the presence of recurrent somatic mutations outside of the JAK-STAT pathway, which accumulate over time, and may impact disease phenotype and outcome. We sought to determine the influence of somatic mutations on clinical phenotype and prognosis.We sequenced a total of 30 genes recurrently mutated in myeloid malignancies in a cohort of 162 MPN patients (pts) using a next generation sequencing platform. The cohort included 49 pts with ET, 26 PV, 38 Primary Myelofibrosis (MF), 11 Post ET MF, 14 Post PV MF, 12 with leukemic transformations of MPN (LT), 7 with MPN-unclassified (MPN-U) and 5 others. Median age was 59 years and 79 were men. A Total of 288 gene mutations were identified with the most commonly mutated genes being JAK2 (n=121, 74%), TET2 (n=31, 19%), DNMT3A (n=18, 11%), ASXL1 (n=16, 10%), IDH2 (n=10, 6%), RAS (n=12, 7%), TYK2 (n=8, 5%) and TP53 (n=7, 4%). We did not find any mutations in NPM1, CBL, SRSF2 and no FLT3 -ITD. CALR was not assessed in 20 pts and these were excluded from mutation number analysis.Importantly, we identified a relationship between the absolute number of mutations found per pt, disease phenotype, and age (table 1). Pts with/without prior chemotherapy or radiotherapy exposure did not have a difference in mutation number (1.5 vs. 1.9). Cases of ET or PV with fibrotic transformation had more mutations in ASXL1, RAS, EZH2, PHF6 and MPL than pre fibrotic ET or PV suggesting these may be relevant in disease progression and development of fibrosis. Mutations in TET2, RAS and PHF6 were more frequent in cases with LT compared to those with chronic phase MPN.Pts over 40 were more likely to have mutations in TET2 (p=0.026) and JAK2 (p=0.019) and ASXL1 mutations were more common in pts with abnormal cytogenetics than in those with normal cytogenetics (p=0.003). Thrombotic events, which are an important cause of morbidity in MPN patients, negatively correlated with mutations in ASXL1 (p=0.044). Prognosis as measured by DIPPS and DIPSS-Plus scores appeared to correlate with the average number of mutations found in MF patients (table 2).We examined several cases for which serial samples were available, and noted the acquisition of new mutational events despite ongoing therapy. We noted that the most commonly acquired mutations occurred in epigenetic modifying (DNMT3A, TET, IDH, ASXL1) and in growth signaling pathway (RAS, CBL) genes. These occurred despite active therapy and often without an overt change in clinical phenotype. Further details of these serial samples will be presented.We conclude that the number and spectrum of somatic mutations correlate with disease phenotype of MPN. Younger pts have fewer mutations, as do pts with normal cytogenetics. JAK2 and TET2 mutations were more common in older pts. We show that a subset of pts acquire mutations in epigenetic modifiers and in genes involved in growth signaling pathways during disease course, and that mutations in TET2, RAS and PHF6 were enriched at the time of leukemic transformation. Taken together, these results indicate that mutations outside the JAK-STAT pathway influence disease phenotype, and that the acquisition of mutations over time may predict for disease progression. Serial evaluation of mutational burden over time therefore warrants exploration in the clinical setting.Table 1Average number of mutations appeared to correlate with disease phenotype, age and abnormal cytogenetics.Average Number of MutationsNMean (SD)P-valueAge < 40 years131.4 (0.9)0.026Age > 40 years122 (1)No Thrombosis1132 (1)0.712Thrombosis281.9 (1)Normal Cytogenetics641.8 (0.9)0.016Abnormal Cytogenetics402.3 (1.2)ET/PV/PMF991.8 (0.8)0.029LT103 (1.5)ET/PV661.6 (0.7)0.01Post ET/PV MF222.3 (1.1)ET441.6 (0.7)< 0.001PV221.5 (0.9)PMF332.2 (0.9)Post ET/PV MF222.3 (1.1)LT103 (1.5)Table 2Disease prognostic scores in MF appear to correlate with the average number of mutations found per patient.Risk categoryNAverage number mutationsDIPSSLow81.5Intermediate-1192.4Intermediate-291.8High15DIPSS-PlusLow61.5Intermediate-1122Intermediate-2142.2High15 [Display omitted] DisclosuresLevine:CTI BioPharma: Membership on an entity's Board of Directors or advisory committees; Loxo Oncology: Membership on an entity's Board of Directors or advisory committees; Foundation Medicine: Consultancy.

A Population-Based Study of Incidence of Myeloproliferative Neoplasms in Sweden Between 2000 and 2012

BackgroundThe Myeloproliferative neoplasms (MPNs) consists of the subtypes polycythemia vera (PV), essential thrombocythemia (ET), primary myelofibrosis (PMF), and MPN unclassifiable (MPN-U). The incidence rates of these diseases vary substantially between different reports, ranging from 1.15 to 4.99/100,000 person-years. However, in a recent metaanalysis, there was no significant difference in MPN incidence between Europe and North America and the variations in incidence may therefore reflect the quality of the cancer registers and reporting of MPNs. In addition, there is a limited number of reports on MPN incidence during more recent years. Therefore, we assessed the incidence of MPN based on the Swedish Cancer Register, a high-quality population-based cancer register between 2000 and 2012.Patients and MethodsThe Swedish Cancer Register was used to identify all patients diagnosed with an MPN between January 1st 2000 and December 31st 2012. These Swedish Cancer Registers have very high levels of quality and completeness. Between 2008 and 2012, the reporting of newly diagnosed MPN to the cancer register was >92%. Information on the Swedish population was obtained from the Human Mortality Database (www.mortality.org). Based on information from these registers, incidence rates of MPNs with 95% confidence intervals (CIs) were calculated. Confidence intervals were estimated on the log scale. In addition, the incidence rate in relation to MPN subtype, age group (18-39, 40-49, 50-59, 60-69, 70-79, and ³80 years), as well as calendar year of diagnosis was assessed.ResultsA total of 5,442 MPN patients were reported to the cancer register between 2000 and 2012. During these years, there were 1,810 incident cases of PV, 1,862 of ET, 636 of PMF, and 1,134 with MPN-U. Between January 1st 2000 and December 31st 2012, the population in Sweden increased from 8,861,426 to 9,555,893 inhabitants.The overall annual incidence rate of MPN was 5.83 (95% CI 5.68-5.99)/100,000 persons. The incidence rate of PV was 1.94 (1.85-2.03), ET 2.00 (1.91-2.09), PMF 0.68 (0.63-0.74), and MPN-U 1.22 (1.15-1.29) per 100,000 person-years. In addition, there was a strong correlation between age and incidence of MPN with incidence rates being substantially higher among the older age groups (Table).The overall incidence rate of MPNs increased during the study period, from 5.06 (4.55-5.62)/100,000 person-years in the year 2000 to 5.98 (5.45-6.55)/100,000 person-years in 2012. The incidence rate of PV was similar throughout the study period, the incidence was 2.05 (1.74-2.42)/100,000 person-years in 2000 and 2.12 (1.81-2.47)/100,000 person-years in 2012. The annual incidence rate of ET and PMF increased, from 1.62 (1.34-1.95) to 2.49 (2.15-2.87) per 100,000 persons for ET and from 0.36 (0.24-0.53) to 0.86 (0.67-1.10) per 100,000 persons for PMF between 2000 and 2012. Conversely, the incidence of MPN-U decreased, 1.03 (0.81-1.29) to 0.52 (0.38-0.71)/100,000 person-years between 2000 and 2012.Summary and ConclusionsIn this large population-based study, the incidence of MPN was higher than previously reported in both European and North American studies. As earlier lower incidence rates likely are an effect of limited coverage of cancer registers, there may be an underreporting of MPNs in many European and American countries. The increase in MPN incidence rates during the study period may reflect increasing life expectancy of the Swedish population, improved reporting to the cancer register as well as changes in the classification and diagnostic systems. Similarly, the decrease in incidence of MPN-U is also likely a result of improved diagnostics during more recent years. In conclusion, the MPN incidences rates reported here are presumably more accurate compared to earlier reports due to the high level of coverage and accuracy of the Swedish registers.Table 1Incidence rates of MPNs overall and in relation to subtype and age at diagnosisTotal number MPN diagnosed 2000-2012Incidence/100 000 person-years (95% confidence interval)All MPN5,4425.83 (5.68-5.99)SubtypePV1,8101.94 (1.85-2.03)ET1,8622.00 (1.91-2.09)PMF6360.68 (0.63-0.74)MPN-U1,1341.22 (1.15-1.29)Age at diagnosis (years)18-392260.67 (0.59-0.76)40-493612.26 (2.04-2.51)50-597694.92 (4.58-5.28)60-691,2289.54 (9.02-10.1)70-791,68018.99 (18.1-19.9)>801,17818.92 (17.87-20.03) DisclosuresLandgren:BMJ Publishing: Honoraria; Bristol-Myers Squibb: Honoraria; Medscape: Honoraria; Onyx: Honoraria; Celgene: Honoraria; International Myeloma Foundation: Research Funding; Medscape: Consultancy; BMJ Publishing: Consultancy; Onyx: Research Funding; Bristol-Myers Squibb: Consultancy; Onyx: Consultancy; Celgene: Consultancy.

Chemical Mutagenesis Screen Identifies Novel Drug Resistant JAK2 Variants in V617FJAK2 Mediated MPN and Predict HSP90 Inhibitors As Possible Agents to Overcome Drug Resistance

JAK2 V617F can be identified in the majority of polycythemia vera cases and in 50% of essential thrombocythemia and idiopathic myelofibrosis patients. JAK2 inhibitors including ruxolitinib, fedratinib and lestaurtinib display clinical activity in trials for PV, ET and IMF, and ruxolitinib has recently been approved for the treatment of primary and secondary myelofibrosis. In other malignancies it has been demonstrated that acquired resistance to kinase inhibitors emerge due to secondary resistance mutations in the targeted kinase. To identify JAK2 point mutations mediating ruxolitinib resistance and predict alternatively treatment strategies, we exposed JAK2 V617F expressing Ba/F3 cells to ruxolitinib. Surprisingly, sublines resistant to ruxolitinib at 1000nM, 2000nM and even 4000nM did not harbor point mutations neither in the kinase nor in the pseudokinase domain of JAK2. However, western blot analysis of sublines resistant to ruxolitinib revealed a 45-kDa JAK2 variant together with full length JAK2 V617F protein in 87% of the cases. Sequencing of the short form in drug resistant clones revealed a novel JAK2 variant missing amino acids 76 to 820 resulting in the N-terminal FERM domain directly fused to the kinase domain of JAK2 (FERM-JAK2). FERM-JAK2 was highly resistant to the ATP-competitive JAK2 inhibitors ruxolitinib and fedratinib. Phospho-deficient mutant studies provided evidence that FERM-JAK2 preferentially exist in an inactive state. This would impede drug binding and explain the resistant phenotype of FERM-JAK2.However, in this study we could not identify other genetic TKI resistant JAK2 variants than FERM-JAK2. This is in remarkable contrast to BCR-ABL mediated CML, where more than 90 residues have been described as TKI resistant variants and might indicate that in case of JAK2, the residues which mediate the drug resistance might comprise the JAK2 kinase function. Therefore, we treated JAK2 V617F expressing Ba/F3 cells with a chemical mutagen (ENU) to predict point mutations in JAK2 that might cause resistance towards the ruxolitinib. Surprisingly, after ENU pretreatment the frequency of drug resistant clones increased and most of the drug resistant clones displayed point mutations in the JAK2 kinase domain. In this screen, we identified L902Q, Y931C, L983F as the most frequent mutations and L902Q+R938E, L902Q+N947Q, L902Q+E1028K and L983F+Q959H as minor mutations. All these mutations confer cross-resistance across a panel of different JAK2 kinase inhibitors except L983FJAK2. L983FJAK2 reduces the sensitivity of JAK2-dependent cells to ruxolitinib and JAK inhibitor-1 but does not reduce the sensitivity of cell proliferation against fedratinib, thereby indicated that we identified a compound specific resistant mutations which is not an ATP-competitor specific mutation.Structure based modeling studies suggest that ruxolitinib is held by numerous hydrophobic interactions with residues Leu 855, Val 863, Ala 880, Val 911, Met 929, Leu 932 and Leu 983 that line the binding pocket. The aromatic ring of Tyr 931 is close enough to the pyrimidine ring to have p-p interaction. Surprisingly, this important interaction does not seem to be critical for the orientation of the inhibitor in the binding pocket as the Y931C mutation does not lead to a different binding pose. Leu 902 does not directly interact with ruxolitinib, however, it is close to the binding pocket and its mutation to Gln with a polar side chain significantly disturbs the inhibitor binding, thus explaining the high resistance of this mutation to ruxolitinib. Mutation of Leu 983 to Phe disrupts important hydrophobic interactions (e.g. Ala 880, Val 911, Met 929) with the pyrrolopyrimidine moiety and induces aromatic-aromatic interaction between the new phenyl ring and the pyrrol and pyrazol rings. Finally, our study also provided evidence that HSP90 inhibitors 17-AAG and geldanamycin are highly potent against TKI resistant FERM-JAK2, L902Q, Y931C and L983FJAK2 through JAK2 degradation and inhibition of the JAK2-STAT5 signaling axis. Taken together, our study highlight HSP90 inhibitors as a promising therapeutic agent in drug resistant mutations against tyrosine kinase inhibitors in MPN. DisclosuresNo relevant conflicts of interest to declare.

Malignant Cerebral Venous Sinus Thrombosis in Polycythemia.

Malignant Cerebral Venous Sinus Thrombosis in Polycythemia.

Analysis of JAK2V617F mutation in Jordanian patients with myeloproliferative neoplasms

Myeloproliferative neoplasms (MPNs) are heterogeneous clonal bone marrow stem cell disorders and include polycythemia vera (PV), essential thrombocythemia (ET), and idiopathic myelofibrosis (IMF) neoplasia. In 2005, the JAK2(V617F) mutation was identified in Philadelphia chromosome-negative patients. The aim of this study was to sequence coding exons 12 and 14 of the JAK2 gene in Jordanian patients with MPN. Both exons 12 and 14 of the JAK2 gene were amplified using polymerase chain reaction from DNA extracted from 68 blood and bone marrow samples belonging to 57 MPN patients and subjected to DNA sequencing. JAK2(V617F) mutations were detected in 26 of 57 Jordanian patients (45%) with different MPNs. JAK2(V617F) was identified in 70%, 31%, and 14% of PV, ET, and IMF cases, respectively. Five men diagnosed with PV were homozygous for JAK2(V617F), whereas the other 21 patients were heterozygous for the mutation. Neither the JAK2(V617F) mutation nor any DNA polymorphism in exon 12 or exon 14 of the JAK2 gene was detected among the 40 leukemic patients. A rare single nucleotide polymorphism, c.1860C→T (rs375442615), was detected in one patient with ET. This study is the first molecular investigation of the JAK2 gene in Jordan. We successfully identified the JAK2(V617F) mutation in Jordanian patients with Philadelphia chromosome-negative MPNs. Our results provide a basis for the early detection of this mutation and simplify the diagnostic workup for these disorders at the molecular level.

The Prevalence of JAK2, MPL, and CALR Mutations in Chinese Patients With BCR-ABL1-Negative Myeloproliferative Neoplasms.

To evaluate the mutation frequency of JAK2 V617F, JAK2 exon 12, MPL exon 10, and CALR exon 9 and the value of the combined tests in the diagnosis of BCR-ABL1-negative myeloproliferative neoplasms (MPNs). In the current study, mutations of JAK2 V617F, JAK2 exon 12, MPL exon 10, and CALR exon 9 were analyzed in 929 Chinese patients with BCR-ABL1-negative MPN, including 234 cases of polycythemia vera (PV), 428 ETs, 187 PMFs, and 80 unclassifiable MPNs (MPN-Us). Our result showed that the positive rate of any of four mutations in patients with PV, ET, PMF, and MPN-U was 89.3%, 83.4%, 87.2%, and 77.5%, respectively, which significantly improved the diagnostic rate, especially in ET and PMF. Meanwhile, we also found that the patients without any of four mutations were younger than those with one or more mutations. Unexpectedly, the coexistence of JAK2 V617F and CALR exon 9 was identified in six (0.6%) patients, and JAK2 V617F and MPL exon 10 were present simultaneously in two (0.2%) patients. In addition, we also identified several novel mutation types in CALR exon 9. The combined genetic tests of JAK2 V617F, JAK2 exon 12, MPL exon 10, and CALR exon 9 help improve the diagnostic rate for BCR-ABL1-negative MPN.

Polycythemia vera associated with IgA nephropathy: A case report and literature review.

A case of polycythemia vera (PV) associated with immunoglobulin A nephropathy (IgAN) in a 57-year-old man is described. The patient had a mild enlargement of the kidneys and elevated serum creatinine level, whereas the glomerular filtration rate was normal. Pathological observation under a light microscope showed mild mesangial hyperplasia. The urinary protein level was found to be positively correlated with changes in blood cell counts. After controlling blood pressure, anti-platelet, hydroxyurea treatment, the patient's proteinuria decreased and renal function remained in the normal range. PV associated with renal disease is rare and generally considered to be associated with hypervolemia or high-viscosity-induced renal hyperperfusion and hyperfiltration. This is a rare case of PV associated with IgAN without a high filtration rate. A review of the clinical features of PV associated with renal disease from previous literature was also conducted. The histological results of the cases varied and included IgAN, focal segmental glomerulosclerosis and membranoproliferative glomerulonephritis.