scholarly journals Clinical, Hematologic, Biologic and Molecular Characteristics of Patients with Myeloproliferative Neoplasms and a Chronic Myelomonocytic Leukemia-Like Phenotype

Cancers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1891
Author(s):  
Sonja Heibl ◽  
Bettina Gisslinger ◽  
Eva Jäger ◽  
Agnes Barna ◽  
Michael Gurbisz ◽  
...  
Keyword(s):  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Chronic Myelomonocytic Leukemia ◽  
Molecular Characteristics ◽  
Molecular Features ◽  
Cell Counts ◽  
Myelomonocytic Leukemia

Patients with a myeloproliferative neoplasm (MPN) sometimes show a chronic myelomonocytic leukemia (CMML)-like phenotype but, according to the 2016 WHO classification, a documented history of an MPN excludes the diagnosis of CMML. Forty-one patients with an MPN (35 polycythemia vera (PV), 5 primary myelofibrosis, 1 essential thrombocythemia) and a CMML-like phenotype (MPN/CMML) were comprehensively characterized regarding clinical, hematologic, biologic and molecular features. The white blood cell counts in MPN/CMML patients were not different from CMML patients and PV patients. The hemoglobin values and platelet counts of these patients were higher than in CMML but lower than in PV, respectively. MPN/CMML patients showed myelomonocytic skewing, a typical in vitro feature of CMML but not of PV. The mutational landscape of MPN/CMML was not different from JAK2-mutated CMML. In two MPN/CMML patients, development of a CMML-like phenotype was associated with a decrease in the JAK2 V617F allelic burden. Finally, the prognosis of MPN/CMML (median overall survival (OS) 27 months) was more similar to CMML (JAK2-mutated, 28 months; JAK2-nonmutated 29 months) than to PV (186 months). In conclusion, we show that patients with MPN and a CMML-like phenotype share more characteristics with CMML than with PV, which may be relevant for their classification and clinical management.

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.

Clinical Phenotype of Myeloproliferative Neoplasms with Activating CBL-mutations Resembles Chronic Myelomonocytic Leukemia.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3895-3895
Author(s):  
Juliana Popa ◽  
Susanne Schnittger ◽  
Philipp Erben ◽  
Tamara Weiss ◽  
Ayalew Tefferi ◽  
...  
Keyword(s):  
Myeloid Leukemia ◽  
Conflicts Of Interest ◽  
Clinical Phenotype ◽  
Myeloproliferative Neoplasms ◽  
Direct Sequencing ◽  
Jak2 V617f ◽  
Chronic Myelomonocytic Leukemia ◽  
A Genome ◽  
Length Mutations ◽  
Myelomonocytic Leukemia

Abstract Abstract 3895 Poster Board III-831 A genome-wide single nucleotide polymorphism (SNP) screen led to the identification of 11q aUPD in patients diagnosed with various subtypes of myeloproliferative neoplasms (MPN), e.g. chronic myelomonocytic leukemia (CMML), atypical chronic myeloid leukemia (aCML) and myelofibrosis (MF) (Grand et al., Blood 2009;113:6182). Further molecular analyses revealed acquired activating point and length mutations in CBL exons 8 and 9 in 10% of CMML, 8% of aCML and 6% of MF cases. Most variants were missense substitutions in the RING or linker domains that abrogated CBL ubiquitin ligase activity and conferred a proliferative advantage to 32D cells overexpressing FLT3. In this study, 160 patients with BCR-ABL and JAK2 V617F negative MPNs were screened for CBL mutations by PCR and direct sequencing. Eighteen known (Y371H, L380P [2x], C381R, C381Y [2x], C384Y, C396Y, H398P, H398Q, W408C, P417H, F418L, R420Q [5x]) and four new (F378L, G397V, I423N, V430M) missense mutations affecting fourteen residues were identified in 20 patients. Two patients harbored two different mutations. The clinical phenotype could be characterized more precisely in 17 patients. Median age was 68 years (range 59–85) with a slight female predominance (f, n=10; m, n=7). Striking hematological features were leukocytosis (14/17; 82%; median 29,000/μl, range 4,500-141,000) with continuously left-shifted granulopoiesis (blasts, promyelocytes, myelocytes, metamyelocytes) in 85% and elevated monocytes (median 2,500/μl, range 630-10,656) >1,000/μL in 88% (15/17) of patients. Eosinophilia (>1,500/μL) was rare (3/17, 18%). Anemia (normal values: f, Hb <12g/dL; m, Hb <14g/dL) was present in all 17 patients (f, median 10g/dL, range 8.7-11.8; m, median 11.2g/dL, range 8.6-12.9). Platelets did not exceed 300,000/μL in any patient while 11/17 (65%) patients presented with thrombocytopenia (median 125,000/μL, range 18,000-271,000). Splenomegaly was present in 11/17 patients (65%) and LDH was elevated (median 304U/L, range 189-729) in 9/17 patients (52%). Bone marrow histology and immunohistochemistry were available from 12 patients. Relevant features were hypercellularity, marked granulopoiesis and microlobulated megakaryocytes without clusters in 11/12 patients (92%), respectively. Increased fibres were seen in 8/12 (67%) patients of whom one showed severe fibrosis. Clinical follow-up was available from 17 patients. Thirteen patients (76%) have died because of progression to secondary acute myeloid leukemia/blast phase (n=7), cytopenia-related complications (n=2) or for unknown reasons (n=4) after a median of 23 months (range 3-60) following diagnosis. In conclusion, point mutations of CBL exons 8 and 9 are present in approximately 6-12% of BCR-ABL and JAK2 V617F negative MPNs. They are associated with a distinct clinical and hematological phenotype presenting with myeloproliferative features allowing diagnosis of a proliferative subtype of CMML rather than aCML or MF in the majority of cases. Patients with left-shifted leukocytosis, monocytosis, anemia and lack of thrombocytosis who are negative for BCR-ABL and point or length mutations of JAK2 should be routinely screened for CBL mutations. Disclosures: No relevant conflicts of interest to declare.

Response to induction or hypomethylating agent therapy among patients with myeloproliferative neoplasms progressing to accelerated or leukemic phase.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e18561-e18561
Author(s):  
Gabriela Hobbs ◽  
Jennifer Lombardi Story ◽  
Maura A. Blaney ◽  
Philip C. Amrein ◽  
Amir Tahmasb Fathi ◽  
...  
Keyword(s):  
Median Survival ◽  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Allogeneic Transplantation ◽  
Rank Test ◽  
Molecular Testing ◽  
Dismal Prognosis ◽  
Poor Outcomes

e18561 Background: Post-myeloproliferative neoplasm (MPN) acute myeloid leukemia (AML) and accelerated phase disease (AP) are associated with poor outcomes; the optimal management of these patients at transformation is uncertain in the era of widely available molecular testing. Methods: We performed a retrospective analysis of adult patients with MPN that had transformed into AML (greater than 20% blasts) or AP (10-19% blasts and dysplastic features) from 2006-2016. Patients were 18 or older at AML/AP diagnosis. Outcomes were described by Kaplan and Meier and the Log rank test. Results: We identified 30 patients, with transformed MPN into AML (n = 23) or AP (n = 7), including one patient in AP at presentation. Most were male (73%). Disease evolved from polycythemia vera (n = 6), essential thrombocythemia (n = 11), primary myelofibrosis (n = 9) and other MPN diagnoses (MPN/MDS overlap, n = 3; MPN NOS, n = 1). The median age at MPN diagnosis was 67.5 yrs, and at transformation 72 yrs. The median time from MPN diagnosis to transformation was 5.6 yrs (range 0.3-36.0). 12 patients had JAK2 V617F testing both at MPN diagnosis and AML diagnosis; 6 had JAK2 mutations at both time points and 2 lost JAK2 at transformation. At AML/AP transformation, 11 patients had NGS mutation testing; the most common somatic mutations were NRAS (5/11), RUNX1 (2/11), and SRSF2 (2/11). 20 patients received treatment outside of supportive care. Of these, 8 achieved a CR or CRi (40%; 7/10 with induction and 1/8 with HMA). The only HMA response was on a trial of HMA+SGN33a. The median survival from AML/AP transformation was 5.8 mo. Of treated patients, median survival was 7.4 mo; 37% of treated patients were alive at 1 yr. Nine patients (31%; 7 with AML and 2 with AP) underwent allogeneic transplantation; 2 relapsed during follow-up. 74% of patients treated with allo-HCT were alive at 1 yr after AML/AP transformation. Conclusions: AML or accelerated phase disease arising out of MPN carries a dismal prognosis. HMA monotherapy had little efficacy in this group (0/7 achieved remission). Allogeneic transplantation offered the best chance of survival at one year, but fewer than a third of patients were able to proceed to transplant.

scholarly journals Combination approach to diagnosis and treatment of an elderly patient with chronic Ph-negative myeloproliferative neoplasm and concomitant surgical pathology. Clinical observation

MD-Onco ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 61-65
Author(s):  
Yu. E. Ryabukhina ◽  
P. A. Zeynalova ◽  
O. I. Timofeeva ◽  
F. M. Abbasbeyli ◽  
T. V. Ponomarev ◽  
...  
Keyword(s):  
Elderly Patient ◽  
Essential Thrombocythemia ◽  
Early Stage ◽  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Left Femur ◽  
Hematopoietic Stem ◽  
Chronic Myeloproliferative Neoplasms

Chronic myeloproliferative neoplasms (CMPN), Ph-negative, are of clonal nature, develop on the level of hematopoietic stem cell and are characterized by proliferation of one or more hematopoietic pathways. Currently, the group of Ph-negative CMPN includes essential thrombocythemia, primary myelofibrosis, polycythemia vera, myeloproliferative neoplasm unclassifiable.Identification of mutations in the Jak2 (V617F), CALR, and MPL genes extended understanding of biological features of Ph-negative CMPN and improved differential diagnosis of myeloid neoplasms. Nonetheless, clinical practice still encounters difficulties in clear separation between such disorders as primary myelofibrosis, early-stage and transformation of essential thrombocythemia into myelofibrosis with high thrombocytosis. Thrombocytosis is one of the main risk factors for thromboembolic complications, especially in elderly people.A clinical case of an elderly patient with fracture of the left femur developed in the context of Ph-negative CMPN (myelofibrosis) with high level of thrombocytosis is presented which in combination with enforced long-term immobilization and presence of additional risk created danger of thrombosis and hemorrhage during surgery and in the postoperative period.

scholarly journals Expression of HMGA2 Collaborates with JAK2V617F to Progress Myeloproliferative Neoplasms

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 482-482
Author(s):  
Koki Ueda ◽  
Kazuhiko Ikeda ◽  
Kazuei Ogawa ◽  
Akiko Shichishima-Nakamura ◽  
Kotaro Shide ◽  
...  
Keyword(s):  
Disease Progression ◽  
Conflicts Of Interest ◽  
Myeloproliferative Neoplasms ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Extramedullary Hematopoiesis ◽  
Hematopoietic Stem ◽  
Cell Counts ◽  
Epigenetic Modifiers ◽  
One Year

Abstract Myeloproliferative neoplasms (MPN) are characterized by chronic proliferation of myeloid cells, extramedullary hematopoiesis and occasional leukemic transformation. Mutations in JAK2, CALR and MPL have been established as drivers of myeloproliferative phenotype, but their roles in disease progression with clonal expansion remain unclear. In addition, studies have shown mutations in epigenetic modifiers including TET2, DNMT3A, ASXL1 and EZH2, and aberrant expressions of microRNAs in MPN, but downstream of these changes is also largely unknown. Recently, we showed high expression of HMGA2 mRNA partly correlated with reduced microRNA let-7 in granulocytes of patients with MPN, including 100% patients with primary myelofibrosis (MF) and 20% polycythemia vera and essential thrombocythemia (Harada-Shirado et al, Brit J Haematol, 2015). In mice, loss of epigenetic modifiers such as BMI1 and EZH2, along with the Arf/Ink4a knockout (Oguro et al, J Exp Med, 2012) or the JAK2 V617F (Sashida et al, ASH, 2013), leads to overexpression of HMGA2 with accelerating MPN. We have generated transgenic (Tg) mice of Hmga2 cDNA with truncated 3'UTR (ΔHmga2) lacking binding sites of let-7 thatrepresses expression of HMGA2 (Ikeda et al, Blood, 2011). Δ Hmga2 mice overexpress HMGA2 and develop MPN-like disease, and represent a clonal advantage in competitive repopulations with serial bone marrow (BM) transplants (BMT). Here, to clarify if HMGA2 affect JAK2 V617F+ hematopoiesis, we crossed Δ Hmga2+/- mice with JAK2 V617F+/- Tg mice (Shide et al, Leukemia, 2008). Δ Hmga2-/-JAK2 V617F-/- wild type (WT), Δ Hmga2+/-JAK2 V617F-/- (Δ Hmga2 -Tg), Δ Hmga2-/-JAK2 V617F+/- (JAK2 V617F-Tg) and Δ Hmga2+/-JAK2 V617F+/- (double-Tg) mice were born at expected Mendelian ratios and we could analyze 5 - 6 of each. At 3 months old, leukocytosis, thrombocytosis, anemia and splenomegaly were most severe in double-Tg compared with JAK2 V617F-Tg or Δ Hmga2 -Tg mice. Relative to WT, peripheral leukocyte and platelet counts were nearly 16- and 4-fold higher in double-Tg, while 3- and 2-fold higher in JAK2 V617F-Tg mice, respectively. Mean spleen weights were 0.067, 0.10, 0.83 and 2.8 g in WT, Δ Hmga2 -Tg, JAK2 V617F-Tg and double-Tg mice, while BM cell counts were 2.4, 2.8, 0.4 and 1.2 x 107/femur, respectively. However, JAK2 V617F-Tg and double-Tg equally showed MF whereas no MF was detected in WT and DHmga2-Tg, suggesting that HMGA2 partly recovers cellularity in fibrotic BM. In the absence and presence of JAK2 V617F, HMGA2 augments lineage- Sca1+ Kit+ cells (WT: Δ Hmga2-Tg: JAK2 V617F-Tg: double-Tg= 0.17%: 0.19%: 0.17%: 0.27% in BM cells), endogenous erythroid colonies (1: 11: 13: 21 CFU-E/104 BM cells) and CD71+ Ter119+ erythroblasts (23%: 29%: 5.7%: 10% in BM and 2.0%: 4.4%: 7.9%: 16% in spleen cells), indicating HMGA2 contributes to expansion of hematopoietic stem/progenitor cells (HSPC) and erythroid commitment in JAK2 V617F+ hematopoiesis. Most Δ Hmga2-Tg and JAK2 V617F-Tg survived for over one year, but all double-Tg mice died within 4 months after birth due to severe splenomegaly and MF with no acute leukemia. To study the effect of HMGA2 on JAK2 V617F+ HSPC activity, we performed BMT with 0.25 x 106 Ly5.2+Δ Hmga2-Tg, JAK2 V617F-Tg or double-Tg cells with 0.75 x 106 Ly5.1+ competitor WT cells to lethally irradiated Ly5.1+ WT mice. Proportions of Ly5.2+ cells were higher in recipients of Δ Hmga2 -Tg than double-Tg cells, while JAK2 V617F-Tg cells were almost rejected at 8 weeks after BMT. To confirm role of HMGA2 without let-7 repression in JAK2 V617F+ hematopoiesis, we performed another BMT with 1 x 104 KIT+ cells of JAK2 V617F-Tg mice transduced with retroviral vector of Hmga2 with each let-7 -site-mutated full-length 3'UTR (Hmga2-m7) to sublethally irradiated WT mice. Recipients of JAK2 V617F-Tg cells with Hmga2-m7 developed MPN-like disease, whereas donor cells were rejected in recipients of JAK2 V617F cells with empty vector. In conclusion, HMGA2 may play a crucial role in hematopoiesis harboring JAK2 V617F by expanding HSPC, leading to disease progression. Disclosures No relevant conflicts of interest to declare.

SRSF2 is Mutated in 47.2% (77/163) of Chronic Myelomonocytic Leukemia (CMML) and Prognostically Favorable in Cases with Concomitant RUNX1 mutations

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 274-274 ◽  
Author(s):  
Susanne Schnittger ◽  
Manja Meggendorfer ◽  
Alexander Kohlmann ◽  
Vera Grossmann ◽  
Kenichi Yoshida ◽  
...  
Keyword(s):  
Hot Spot ◽  
Myeloproliferative Neoplasm ◽  
Gene Mutations ◽  
Chronic Myelomonocytic Leukemia ◽  
Structural Basis ◽  
Employment Equity ◽  
Cell Counts ◽  
Number Of Genes ◽  
Equity Ownership ◽  
Myelomonocytic Leukemia

Abstract Abstract 274 Introduction: Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic malignancy characterized by features of both a myeloproliferative neoplasm and a myelodysplastic syndrome. We previously investigated 81 CMML cases and detected a number of genes frequently mutated (TET2 44.4%, CBL 22.2%, NRAS 22.2%, KRAS 12.3%, JAK2 9.8%, RUNX1 8.7%, EZH2 12.3% (Kohlmann et al., JCO, 2010; Grossmann et al., Leukemia, 2011). Recently, we detected a new candidate gene, SRSF2 (serine/arginine-rich splicing factor 2, also known as SC35) that is a component of the RNA splicing machinery and found it to be frequently mutated in MDS. Aim: As CMML has been increasingly characterized by a growing number of genes during the last years we here analyzed both the frequency of SRSF2 mutations in this entity and the relevance in the context of other previously described gene mutations, as well as to look for a potential prognostic implication. Patients and Methods: In total, 163 cases with CMML (CMML-1 n=105, CMML-2 n=58) were included. The cohort comprised 115 males and 48 females with a median age of 72.8 yrs (range: 21.9 – 88.8 yrs) including all 81 pts that have been published previously. 112 cases (69%) had a normal karyotype and 51 (31%) showed aberrant karyotypes. The mutational hot spot region of SRSF2 around Proline codon 95 (P95) was analyzed by Sanger sequencing in all cases. Data on further mutations were available in respective subcohorts: ASXL1 (n=128), CBL (n=162), EZH2 (n=134), JAK2V617F (n=162), KRAS (n=140), NRAS (n=79), RUNX1 (n=156), TET2 (n=143), TP53 (n=80). Results:SRSF2 mutations of P95 were detected in 77/163 (47.2%) of all cases (49/105, 46.7% in CMML-1, and 28/58, 48.3% in CMML-2). In detail, 74 cases had a missense mutation leading to a change of P95 to P95H (n=33), P95L (n=24), P95R (n=16) or P95A (n=1). In further 3 cases a newly described 24 bp (8 amino acids) deletion starting at P95 was observed. All cases had a mutation load of approximately 50%. The mutations were correlated with higher age (73.3 yrs vs 68.7 yrs in the SRSF2wt cases, p=0.010) and higher hemoglobin levels (11.4 vs 10.5 g/dl in the SRSF2wt cases, p=0.019) whereas white blood cell counts were not different. Further, SRSF2 mutations were mutually exclusive of EZH2 mutations (0/12, 0% vs. 66/122, 54.1% in the EZH2wt, p<0.001) whereas a high coincidence occurred with RUNX1 mutations (22/35, 62.9% vs 52/121, 43% in the RUNX1wt, p=0.054) and TET2 mutations (50/82, 61% vs 18/61, 29.5% in the TET2wt, p<0.001). With respect to associations with all other gene mutations investigated and karyotype no specific pattern was observed. In the total cohort no impact of SRSF2 on survival was observed. Because of the high coincidence of SRSF2mut with RUNX1mut and TET2mut, we performed an analysis in these specific subcohorts. No impact of SRSF2mut in the TET2mut subcohort was found. Whereas in the RUNX1mut subcohort SRSF2mut had a favorable impact on overall survival compared to SRSF2wt (median OS: 108.0 months vs 41.8 months, p=0.05). Conclusions:SRSF2 has recently been described as a new marker in CMML and demonstrated to be useful to delineate further the genetic defects of this disease. This very frequent new mutation is characterized by higher age, higher hemoglobin levels and a high coincidence with TET2 and RUNX1 mutations. It is mutually exclusive of EZH2 mutations. In the subset of RUNX1 mutated CMML SRSF2 mutations demonstrated a favorable impact on outcome. Furthermore, for the first time a 24 bp deletion was observed in three cases that may provide further insight into the structural basis for the abnormal function of SRSF2. Disclosures: Schnittger: MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Meggendorfer:MLL Munich Leukemia Laboratory: Employment. Kohlmann:MLL Munich Leukemia Laboratory: Employment. Grossmann:MLL Munich Leukemia Laboratory: Employment. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.

Association Between EZH2 and Other Acquired Mutations In Myelofibrosis and Myelodysplastic/Myeloproliferative Neoplasms

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 625-625
Author(s):  
Thomas Ernst ◽  
Joannah Score ◽  
Claire E Hidalgo-Curtis ◽  
Amy V Jones ◽  
Andreas Hochhaus ◽  
...  
Keyword(s):  
Conflicts Of Interest ◽  
Myeloproliferative Neoplasms ◽  
Uniparental Disomy ◽  
Myeloproliferative Neoplasm ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Mutational Status ◽  
Significant Difference ◽  
Chromosome 7Q ◽  
Secondary Myelofibrosis

Abstract Abstract 625 We recently identified EZH2 as the major target of chromosome 7q acquired uniparental disomy (aUPD) in myeloproliferative neoplasm (MPN) and myelodysplastic syndromes (MDS). To determine the prevalence of EZH2 mutations we screened all coding exons for mutations in total of 624 cases with myeloid disorders (MPN, n=157; MDS, n=154; MDS/MPN, n=219; AML, n=54, CML in transformation, n=40) and found 49 monoallelic or biallelic EZH2 mutations in 42 individuals, most commonly MDS/MPN (27/219; 12%), primary or secondary myelofibrosis (4/30; 13%) and MDS (9/154; 6%). To determine if EZH2 mutations might co-operate with other known abnormalities or whether they might be mutually exclusive, we tested the mutational status of TET2, ASXL1, CBL, RUNX1, CEBPA, FLT3, NPM1, and WT1 in 187 of the 219 MDS/MPN cases that were screened for EZH2. We also tested an additional cohort of 52 primary myelofibrosis cases for both EZH2 and JAK2 V617F mutations. Of the 187 MDS/MPN cases (CMML, n=97; atypical CML, n=68; MDS/MPN-U, n=22), mutations were seen most frequently in TET2 (67/187; 36%), followed by ASXL1 (38/187, 20%; not including cases with the controversial c.1934dupG variant), RUNX1 (27/187; 14%), EZH2 (25/187; 13%), CBL (22/175; 13%), FLT3 (8/187; 4%), CEBPA (7/187; 4%), NPM1 (6/187; 3%) and WT1 (2/187; 1%). Sixty six (35%) cases tested negative for mutations in all 9 genes. Of the 25 cases with EZH2 mutations, 22 (88%) had mutations in at least one other gene, most frequently TET2 (n=11) and ASXL1 (n=10). EZH2 mutations were also seen in combination with mutations in CBL (n=5), CEBPA (n=4), RUNX1 (n=3) and FLT3 (n=2), however there was no significant difference in the frequency of other mutations on comparison of EZH2 mutated and EZH2 unmutated cases. When the analysis was restricted to the 10 cases with homozygous EZH2 mutations, a similar heterogeneity was observed with mutations in CBL, RUNX1, CEPBA and TET2 only (n=1 for each gene), ASXL1 only (n=2), TET2+ASXL1 (n=1), TET2+ASXL1+RUNX1 (n=1) or no other mutation (n=2). Analysis of CFU-GM from one case that tested positive for both EZH2 and TET2 mutations revealed a complex pattern with an EZH2 mutation clearly preceding the sequential acquisition of two TET2 mutations. Of the 82 primary and secondary myelofibrosis cases, 9 (11%) tested positive for an EZH2 mutation. Of these, 5 were positive for JAK2 V617F and 4 were negative. In 2 cases both EZH2 and JAK2 V617F were homozygous indicating that the predominant clone must harbor both mutations. Overall, these data indicate a complex interaction between different abnormalities with little indication of co-operativity or functional redundancy. Whilst these observations will need to be refined by detailed analysis of single clones, they do suggest that the development of both myelofibrosis and MDS/MPN requires functional alterations in multiple pathways. Disclosures: No relevant conflicts of interest to declare.

Effects of the JAK2 mutation on the hematopoietic stem and progenitor compartment in human myeloproliferative neoplasms

Blood ◽  
2011 ◽  
Vol 118 (1) ◽  
pp. 177-181 ◽  
Author(s):  
Shubha Anand ◽  
Frances Stedham ◽  
Philip Beer ◽  
Emma Gudgin ◽  
Christina A. Ortmann ◽  
...  
Keyword(s):  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Jak2 V617f ◽  
Myeloid Differentiation ◽  
Jak2 Mutation ◽  
Hematopoietic Stem ◽  
Progenitor Compartment ◽  
Proliferative Advantage

Abstract The JAK2 V617F mutation is present in the majority of patients with a myeloproliferative neoplasm (MPN) and is sufficient to recapitulate an MPN in murine models. However, the consequences of JAK2 mutations for myeloid differentiation are poorly understood. After systematic analyses of a large cohort of JAK2-mutated MPN patients, we demonstrate in vivo that JAK2 mutations do not alter hematopoietic stem and progenitor cell com-partment size or in vitro behavior but generate expansion of later myeloid differentiation compartments, where homozygous expression of the mutation confers an added proliferative advantage at the single-cell level. In addition, we demonstrate that these findings may be partially explained by the expression pattern of JAK2, which markedly increases on myeloid differentiation. Our findings have potential clinical relevance, as they predict that JAK2 inhibitors may control myeloproliferation, but may have limited efficacy in eradicating the leukemic stem cells that sustain the human MPN.

scholarly journals Molecular Basis and Clinical Application of Growth-Factor-Independent In Vitro Myeloid Colony Formation in Chronic Myelomonocytic Leukemia

2020 ◽  
Vol 21 (17) ◽  
pp. 6057
Author(s):  
Klaus Geissler ◽  
Eva Jäger ◽  
Agnes Barna ◽  
Michael Gurbisz ◽  
Temeida Graf ◽  
...  
Keyword(s):  
Growth Factor ◽  
Colony Formation ◽  
Molecular Basis ◽  
Strong Predictor ◽  
Chronic Myelomonocytic Leukemia ◽  
Molecular Profile ◽  
Molecular Features ◽  
Increased Risk ◽  
Myelomonocytic Leukemia

We have originally reported that colony-forming units granulocyte/macrophage (CFU-GM) formation is an in vitro feature of chronic myelomonocytic leukemia (CMML) and a strong predictor for short survival. Elucidation of the molecular basis underlying this in vitro phenomenon could be helpful to define molecular features that predict inferior outcome in patients. We studied the correlation between the mutational landscape and spontaneous colony formation in 164 samples from 125 CMML patients. As compared to wildtype samples, spontaneous in vitro CFU-GM formation was significantly increased in samples containing mutations in NRAS, CBL and EZH2 that were confirmed as independent stimulatory factors by multiple regression analysis. Inducible expression of mutated RAS but not JAK2 was able to induce growth factor independence of Ba/F3 cells. Whereas high colony CFU-GM growth was a strong unfavorable parameter for survival (p < 0.00001) and time to transformation (p = 0.01390), no single mutated gene had the power to significantly predict for both outcome parameters. A composite molecular parameter including NRAS/CBL/EZH2, however, was predictive for inferior survival (p = 0.00059) as well as for increased risk of transformation (p = 0.01429). In conclusion, we show that the composite molecular profile NRAS/CBL/EZH2 derived from its impact on spontaneous in vitro myeloid colony formation improves the predictive power over single molecular parameters in patients with CMML.

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