New mutations and pathogenesis of myeloproliferative neoplasms

Blood ◽  
2011 ◽  
Vol 118 (7) ◽  
pp. 1723-1735 ◽  
Author(s):  
William Vainchenker ◽  
François Delhommeau ◽  
Stefan N. Constantinescu ◽  
Olivier A. Bernard
Keyword(s):  
Signaling Pathways ◽  
Intracellular Signaling ◽  
De Novo ◽  
Clonal Selection ◽  
Myeloproliferative Neoplasms ◽  
Blast Crisis ◽  
Chronic Phase ◽  
Janus Kinase ◽  
Prognostic Impact ◽  
Loss Of Function

Abstract Myeloproliferative neoplasms (MPNs) are clonal disorders characterized by excessive production of mature blood cells. In the majority of classic MPN—polycythemia vera, essential thrombocythemia, and primitive myelofibrosis—driver oncogenic mutations affecting Janus kinase 2 (JAK2) or MPL lead to constitutive activation of cytokine-regulated intracellular signaling pathways. LNK, c-CBL, or SOCSs (all negative regulators of signaling pathways), although infrequently targeted, may either drive the disease or synergize with JAK2 and MPL mutations. IZF1 deletions or TP53 mutations are mainly found at transformation phases and are present at greater frequency than in de novo acute myeloid leukemias. Loss-of-function mutations in 3 genes involved in epigenetic regulation, TET2, ASXL1, and EZH2, may be early events preceding JAK2V617F but may also occur late during disease progression. They are more frequently observed in PMF than PV and ET and are also present in other types of malignant myeloid diseases. A likely hypothesis is that they facilitate clonal selection, allowing the dominance of the JAK2V617F subclone during the chronic phase and, together with cooperating mutations, promote blast crisis. Their precise roles in hematopoiesis and in the pathogenesis of MPN, as well as their prognostic impact and potential as a therapeutic target, are currently under investigation.

Fusion Gene Detection Using Whole Transcriptome Analysis in Patients with Chronic Myeloproliferative Neoplasms and Secondary Acute Myeloid Leukemia

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4093-4093 ◽  
Author(s):  
Fiorella Schischlik ◽  
Jelena D. Milosevic Feenstra ◽  
Elisa Rumi ◽  
Daniela Pietra ◽  
Bettina Gisslinger ◽  
...  
Keyword(s):  
Myeloid Leukemia ◽  
Research Funding ◽  
De Novo ◽  
Fusion Gene ◽  
Myeloproliferative Neoplasms ◽  
Chronic Phase ◽  
Loss Of Function ◽  
Secondary Aml ◽  
De Novo Aml ◽  
Whole Transcriptome

Abstract Fusion oncogenes resulting from chromosomal aberrations are common disease drivers in myeloid malignancies. The most prominent example is BCR-ABL1 fusion present in chronic myeloid leukemia, which together with essential thromobocythemia (ET), primary myelofibrosis (PMF) and polycythemia vera (PV) belongs to the classic myeloproliferative neoplasms (MPN). The BCR-ABL1 negative MPNs are driven by somatic mutations in JAK2, MPL and CALR. MPN patients can progress to acute myeloid leukemia (AML) but the transformation process is not well understood. Studies using standard karyotyping and SNP microarrays have shown that disease progression is characterized by an increase in karyotype complexity. We aimed to identify novel fusion oncogenes in patients with BCR-ABL1 negative MPN during chronic phase and disease progression in high-throughput and cost-efficient manner using RNA-seq technology. In addition this approach enabled us to perform RNA-seq variant calling for identification of gene mutations on the same cohort of patients. Whole transcriptome sequencing was performed on 121 patients (112 chronic phase MPN and 9 secondary AML samples) and 23 healthy controls in a 100 base pair paired-end manner. The cohort consisted of 44% PMF, 22% ET, 12% PV and 6% secondary AML patients. The output of three fusion detection tools (Defuse, Tophat-fusion and SOAPfuse) was combined in order to increase sensitivity. Extensive filtering steps were applied in order to enrich for cancer specific fusion events, including filtering for fusions appearing in healthy individuals, filtering for read-throughs and false positives with external databases and manual inspection of sequencing reads. The outcome of analysis for Defuse, Tophat-fusion and SOAPfuse resulted in the total of 52, 54 and 38 candidate fusions, respectively. Candidate fusions were Sanger-sequenced and for Tophat-fusion and Defuse the validation rate was 60%, while for SOAPfuse only 20% could be validated. Approximately 70% of the fusion candidates were not shared among the 3 tools which underlines the importance of selecting the union of all calls from each tool rather than the intersect. We did not observe clustering of breakpoints along the genome. Most fusion candidates could be detected in PMF which corresponds to the disease entity that was most represented in the cohort (44% of patients). No enrichment for fusions was found in 7 triple negative (no JAK2, CALR, MPL mutations) cases. 42% of chromosomal aberrations were translocations, followed by duplication (31%), inversion (14%) and deletion events (11%). Among the intragenic fusions, approximately half had genomic breakpoints less than 1 Mb apart. 70% of validated fusions were out of frame, while 28% were in frame. In the leukemic samples a higher abundance of fusions was found (4/9). Typical fusions for de novo AML were not detected within secondary AML (sAML) samples. We did not detect a recurrent fusion oncogene in our patient cohort. In a PMF patient with JAK2-V617F mutation we identified a BCR-ABL1 fusion, indicating a clonal exchange which was consistent with patient's phenotype. Another PMF patient exhibited an inversion event involving the first exon of CUX1, causing a CUX1 loss of function. Other fusions in chronic MPN patients affected genes involved in histone modifications (SMYD3-AHCTF1, KDM4B-CYHR1). In post-MPN AML patients we identified a somatic in frame-fusion involving INO80D and GPR1 and a fusion truncating the first 3 exons of RUNX2 (XPO5-RUNX2). The high quality of RNA sequencing data, allowed us to set up a variant detection workflow that will be compared with matched samples that have been exome sequenced. Preliminary results could demonstrate that mutations in the JAK2 gene in a cohort of 96 patients were all correctly recalled, emphasizing its sensitivity. Fusion events among patients in chronic phase MPN are rare and the majority of these events imply loss of function of both fusion gene partners. This approach adds valuable information on the true frequency of inactivation of genes such as CUX1 in patients, as small inversions like the one described above would not be detectable by other methods. Detection of a subclone with BCR-ABL1 fusion underlines the strength of the fusion detection workflow for diagnostic purposes. Typical de novo AML fusions were not found in sAML and further suggests that de novo AML and sAML are distinct disease entities on a genetic level. Disclosures Gisslinger: Janssen Cilag: Honoraria, Speakers Bureau; Sanofi Aventis: Consultancy; AOP ORPHAN: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau; Geron: Consultancy. Kralovics:AOP Orphan: Research Funding; Qiagen: Membership on an entity's Board of Directors or advisory committees.

scholarly journals Study of intracellular signaling pathways in Chronic Myeloproliferative Neoplasms

2018 ◽  
Author(s):  
Serena Martinelli
Keyword(s):  
Signaling Pathways ◽  
Intracellular Signaling ◽  
Myeloproliferative Neoplasms ◽  
Mtor Pathway ◽  
Janus Kinase ◽  
Pi3k Inhibitor ◽  
Chronic Myeloproliferative Neoplasms ◽  
Intracellular Signaling Pathways

A gain-of-function mutation in Janus kinase 2 (JAK2V617F) is at the basis of the majority of chronic myeloproliferative neoplasms (MPN). Enhanced activation of other downstream pathways including the PI3K/mTOR pathway has been documented as well. In this study we evaluated the effects of JAK1/2 inhibitors, alone and in combination with mTOR, with a dual mTOR/PI3K inhibitor and with a pan PI3K inhibitor in in-vitro and in-vivo MPN models. Our findings of strong synergy between the JAK2 inhibitors and mTOR/PI3K inhibitor suggested that we might be able to administer these drugs at lower concentrations than when the drugs are used individually. This provides a framework for combination trials using compounds in patients with myeloproliferative neoplasms

scholarly journals Clonal evolution and clinical implications of genetic abnormalities in blastic transformation of chronic myeloid leukaemia

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yotaro Ochi ◽  
Kenichi Yoshida ◽  
Ying-Jung Huang ◽  
Ming-Chung Kuo ◽  
Yasuhito Nannya ◽  
...  
Keyword(s):  
Chronic Myeloid Leukaemia ◽  
Myeloid Leukaemia ◽  
Kinase Inhibitors ◽  
Blast Crisis ◽  
Clonal Evolution ◽  
Chronic Phase ◽  
Genetic Alterations ◽  
Prognostic Impact ◽  
Genetic Abnormalities ◽  
Prior Use

AbstractBlast crisis (BC) predicts dismal outcomes in patients with chronic myeloid leukaemia (CML). Although additional genetic alterations play a central role in BC, the landscape and prognostic impact of these alterations remain elusive. Here, we comprehensively investigate genetic abnormalities in 136 BC and 148 chronic phase (CP) samples obtained from 216 CML patients using exome and targeted sequencing. One or more genetic abnormalities are found in 126 (92.6%) out of the 136 BC patients, including the RUNX1-ETS2 fusion and NBEAL2 mutations. The number of genetic alterations increase during the transition from CP to BC, which is markedly suppressed by tyrosine kinase inhibitors (TKIs). The lineage of the BC and prior use of TKIs correlate with distinct molecular profiles. Notably, genetic alterations, rather than clinical variables, contribute to a better prediction of BC prognosis. In conclusion, genetic abnormalities can help predict clinical outcomes and can guide clinical decisions in CML.

RUNX1 DNA-binding mutations and RUNX1-PRDM16 cryptic fusions in BCR-ABL+ leukemias are frequently associated with secondary trisomy 21 and may contribute to clonal evolution and imatinib resistance

Blood ◽  
2008 ◽  
Vol 111 (7) ◽  
pp. 3735-3741 ◽  
Author(s):  
Catherine Roche-Lestienne ◽  
Lauréline Deluche ◽  
Sélim Corm ◽  
Isabelle Tigaud ◽  
Sami Joha ◽  
...  
Keyword(s):  
Dna Binding ◽  
High Frequency ◽  
Trisomy 21 ◽  
De Novo ◽  
Blast Crisis ◽  
Clonal Evolution ◽  
Chronic Phase ◽  
Chromosome 21 ◽  
Imatinib Resistance ◽  
Molecular Abnormalities

Abstract Acquired molecular abnormalities (mutations or chromosomal translocations) of the RUNX1 transcription factor gene are frequent in acute myeloblastic leukemias (AMLs) and in therapy-related myelodysplastic syndromes, but rarely in acute lymphoblastic leukemias (ALLs) and chronic myelogenous leukemias (CMLs). Among 18 BCR-ABL+ leukemias presenting acquired trisomy of chromosome 21, we report a high frequency (33%) of recurrent point mutations (4 in myeloid blast crisis [BC] CML and one in chronic phase CML) within the DNA-binding region of RUNX1. We did not found any mutation in de novo BCR-ABL+ ALLs or lymphoid BC CML. Emergence of the RUNX1 mutations was detected at diagnosis or before the acquisition of trisomy 21 during disease progression. In addition, we also report a high frequency of cryptic chromosomal RUNX1 translocation to a novel recently described gene partner, PRDM16 on chromosome 1p36, for 3 (21.4%) of 14 investigated patients: 2 myeloid BC CMLs and, for the first time, 1 therapy-related BCR-ABL+ ALL. Two patients presented both RUNX1 mutations and RUNX1-PRDM16 fusion. These events are associated with a short survival and support the concept of a cooperative effect of BCR-ABL with molecular RUNX1 abnormalities on the differentiation arrest phenotype observed during progression of CML and in BCR-ABL+ ALL.

scholarly journals Expression of axl, a transforming receptor tyrosine kinase, in normal and malignant hematopoiesis

Blood ◽  
1994 ◽  
Vol 84 (6) ◽  
pp. 1931-1941 ◽  
Author(s):  
A Neubauer ◽  
A Fiebeler ◽  
DK Graham ◽  
JP O'Bryan ◽  
CA Schmidt ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Intracellular Signaling ◽  
Myeloid Leukemia ◽  
Blast Crisis ◽  
Chronic Phase ◽  
Lymphocytic Leukemia ◽  
Myelogenous Leukemia ◽  
Hematopoietic Tissue ◽  
Blood Leukocytes

Abstract We previously reported the cloning, and characterization of a receptor tyrosine kinase, axl, from two patients with chronic myelogenous leukemia. Herein, we describe the expression pattern of axl in normal and malignant hematopoietic tissue axl message is detected in normal human bone marrow but not significantly in normal blood leukocytes. Cell separation experiments showed that axl is expressed in hematopoietic CD34+ progenitor and marrow stromal cells, at low levels in peripheral monocytes, but not in lymphocytes or granulocytes. Consistent with the normal pattern of axl expression, axl RNA was found predominantly in diseases of the myeloid lineage: 39 of 66 (59%) patients with myeloproliferative disorders (acute myeloid leukemia, chronic myeloid leukemia (CML) in chronic phase, CML in myeloid blast crisis, and myelodysplasia) showed significant axl transcription, as compared with 1 of 45 (2%) lymphoid leukemias (chronic lymphocytic leukemia, acute lymphocytic leukemia, and CML in lymphoid blast crisis). Treatment of K562 cells with the phorbol ester, 12-O- tetradecanoylphorbol-13-acetate (TPA), administration of interferon alpha (IFN alpha) to normal monocytes, and treatment of U937 cells with TPA and IFN tau significantly induced axl expression, supporting a role for this kinase in the intracellular signaling of myeloid cells through a variety of biochemical pathways. These results suggest that the axl kinase may be operative in normal and malignant myeloid biology.

Different Isoforms of the B-Cell Mutator Activation-Induced Cytidine Deaminase (AID) Are Aberrantly Over-Expressed in BCR-ABL1-Positive Acute Lymphoblastic Leukemia (ALL) Patients and Promote Genetic Instability.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1497-1497
Author(s):  
Ilaria Iacobucci ◽  
Annalisa Lonetti ◽  
Anna Ferrari ◽  
Simona Soverini ◽  
Emanuela Ottaviani ◽  
...  
Keyword(s):  
Genetic Instability ◽  
De Novo ◽  
Splice Variants ◽  
Cytidine Deaminase ◽  
Blast Crisis ◽  
Chronic Phase ◽  
Wild Type ◽  
Genome Wide ◽  
A Genome ◽  
Activation Induced Cytidine Deaminase

Abstract Background: BCR-ABL1-positive ALL is the most frequent and prognostically most unfavorable subtype of adult ALL. The main reason for the poor clinical outcome of BCR-ABL1-positive ALL is genetic instability. However, how normal B-cell precursor cells acquire the genetic changes that lead to transformation and progression has not been completely defined. Activation-induced cytidine deaminase (AID) produces immunediversity by inducing somatic hypermutations and class-switch recombinations in human immunoglobulin genes (Ig). Aim: Since at much lower frequency AID can also target non-Ig genes and may even act as a genome-wide mutator, we investigated whether AID was expressed in BCR-ABL1-positive ALL and in chronic myeloid leukemia (CML) at the time of progression to blast crisis. Patients and methods: We analyzed 61 adult de novo Ph+ ALL patients (pts) and 60 CML pts (chronic phase and myeloid/lymphoid blast crisis). AID cDNA, obtained from bone marrow or peripheral blood, was amplified with two pairs of oligonucleotides, the forward primer of each couple conjugated with a fluorescent dye (fluorescein) at its 5′ end. PCR products were then loaded on the ABI Prism 3730 DNA Analyzer for automated capillary gel electrophoresis and the results were plotted with the AbiPrism GeneMapper v3.5 software (Applied Biosystems). Results: On the 61 de novo adult BCR-ABL1-positive ALL pts, AID mRNA and protein were detected in 41 (67%). AID expression correlated with the BCR-ABL1 transcript levels and disappeared after treatment with tyrosine kinase inhibitors at the time of remission. Moreover, AID expression was also found in lymphoid blast crisis CML (60%), but not in myeloid lineage or in chronic phase CML. Different isoforms of AID were expressed. In 10/61 (16%) BCR-ABL1-positive ALL pts the full-length isoform (GeneBank accession number NM_020661) was identified, in 16/61 (26%) the co-expression of the wild-type isoform and of different AID splice variants was found and in 15/61 (25%) only the expression of splice variants was found. These can result from retention of intron 4 (Variant A), omission of exon 4 (Variant B) and 3 (Variant C), and from a deletion of 30 bp in the initial portion of exon 4 (Variant D). In the wild-type mRNA, codon 148 spans exons 3 and 4. In both variants A and B, mRNA splicing disrupts this codon and causes a frameshift, which results in a premature stop codon. If translated, the splice variants produce truncated proteins of 187 and 145 amino acids, respectively. However, the putative deaminase active site, encoded by exon 3, is preserved in both splice variants, but is lacking in the variant C. Since enforced expression of Pax5 induces endogenous AID gene expression, we analyzed the expression levels of Pax5 in all pts (ΔΔCt method, GAPDH as control gene). As expected, we found a very strong difference (p<0.0001) between chronic phase CML and BCR-ABL1-positive ALL, but total Pax5-transcripts did not differ significantly when BCR-ABL1-positive ALL/AID+ and BCR-ABL1-positive ALL/AID− were compared. To investigate whether AID introduces DNA-single strand breaks in BCR-ABL1-positive ALL, we performed a genome wide analysis by 250K NspI single nucleotide polymorphism (SNP) array (Affymetrix Inc., USA). We identified a region of high level amplification and homozygous deletion in all patients. Patients who expressed wild-type AID had a higher number of alterations compared to AID-negative patients (median copy number alteration of 14, range 5–27, versus 4, range 1–6, respectively, p<0.03). Recurring copy number abnormalities were identified in genes with an established role in leukemogenesis, such as IKZF1, CDKN2A, CDKN2B, PAX5, MELK, BTG1 and MDS1. AID consensus motifs (DGYW/WRCH) were mapped very close to the breakpoint cluster regions. Conclusions: Our findings show that BCR-ABL1-positive ALL cells aberrantly express different isoforms of AID that can act as a mutator outside the Ig gene loci in promoting genetic instability in leukemia cells.

NPM1 Mutations Have a High Impact On the Development of Secondary AML.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 999-999
Author(s):  
Susanne Schnittger ◽  
Tamara Weiss ◽  
Frank Dicker ◽  
Jana Sundermann ◽  
Wolfgang Kern ◽  
...  
Keyword(s):  
De Novo ◽  
Myeloproliferative Neoplasms ◽  
Blast Crisis ◽  
Nras Mutation ◽  
Npm1 Mutation ◽  
Secondary Aml ◽  
Second Hit ◽  
Total Cohort ◽  
Equity Ownership ◽  
De Novo Aml

Abstract Abstract 999 Poster Board I-21 NPM1 mutations are frequently reported to be typical for de novo AML and are regarded as prognostically favorable if not associated with FLT3-ITD. These mutations have rarely been reported in secondary AML after myelodysplastic syndrome (MDS) or after myeloproliferative neoplasms (MPN). We have detected NPM1 mutations in 37/283 patients with AML after a previous MDS (s-AML) (13.1%) and in 6/67 after a previous MPN (9%). Here we describe the characteristics of these 43 NPM1 mutated s-AML cases to show the involvement of NPM1 mutations in development of secondary AML. The total cohort of 43 cases was composed of 22 males and 21 females with a median age of 71.3 years (range: 29.3-87.7 years). Cytogenetics was available in 40 of the 43 cases (93%). 27 of these had a normal karyotpye whereas 13 revealed one of these aberrations: +4 (n=3), t(1;14)(p34;q32) (n=1); -7 (n=1), del(9q) (n=2), +13 (n=1); +21 (n=1), -Y (n=1); i(X)(p10) (n=1), [+1,der(1;13)(q10;q10),+i(5)(p10),+8] (n=1) and a t(5;12)(q33;p13) (n=1). All 43 samples were analysed for MLL-PTD, FLT3-ITD, FLT3-TKD, NRAS, CEBPA, RUNX1 mutations as well as for KITD816 and JAK2V617F mutations. The incidence of additional cooperating mutations was similar to de novo AML. FLT3-ITD was detected in 14/37 AML after MDS (37.8%) and only once (1/6) after MPN. FLT3-TKD was observed in 3/37 case after MDS (8.1%) and never after MPN. In addition there was one case with RUNX1 and 4 cases (10.8%) with NRAS mutation after MDS. In none of the cases a CEBPA mutation or MLL-PTD was observed. Thus a total of 18/37 cases (48.8%) after MDS revealed a further molecular mutation in addition to NPM1. Of those without additional molecular mutations (only NPM1) 4 cases revealed cytogenetic aberrations resulting in 22/37 cases (59.5%) with additional cytogenetic or molecular mutations. Also in the 6 cases with NPM1 after MPN we detected a high proportion of additional mutations. Two of these 6 cases defined to be after MPN had a history of KITD816V mutated mastocytosis. Two further cases had preceding JAK2V617F mutated MPN and one additional carried an ETV6-PDGFRB rearrangement. In all these 5 transformed MPN cases the initial typical MPN mutation was retained in AML (blast crisis) whereas the NPM1 mutation was acquired and may have served as a second hit in the development to AML. One of the two JAK2+/NPM1+ cases in addition also acquired an FLT3-ITD. From 11 of the s-AML cases a paired sample from the timepoint of MDS was available. Retrospectively the NPM1 mutations was retraced by mutation specific realtime PCR and also all other markers were analysed. Three different patterns were observed: 1) in two cases the NPM1 mutation was not detectable in MDS (analysed 35 and 11 months before diagnosis of s-AML). In one case an NPM1/ABL1 level of 1.6% was detectable 6 months after diagnosis of MDS and a level of 2129% eleven months after diagnosis of MDS. 2) In six cases the NPM1 mutation was not detectable with standard methods in MDS, but with sensitive Real time PCR a ratio of 1-4 log below the s-AML level was already detectable 6-17 months before onset of s-AML. 3) In three further cases a high NPM1 level comparable to that in s-AML was already detectable in MDS 2-12 months before s-AML evolved. These three cases gained an FLT3-ITD at the time point of transformation from MDS to AML. These pattern show that NPM1 can be an early or a late event in transformation to s-AML and although the acquisition of mutations seems to be important in the transformation to AML the sequence of the single events seem to be secondary. As NPM1 have a favourable prognosis in de novo AML if not associated with FLT3-ITD we did a respective analysis for overall survival (OS) and (EFS) for our cohort of s-AML after MDS. For this analysis 278 s-AML patients were available: NPM1-/FLT3- (n=223); NPM1+/FLT3- (n=20), NPM1-/FLT3+ (n=20) and NPM1+/FLT3+ (n=12). The total cohort revealed a bad outcome (median OS: 56.6 days and median EFS: 43.5 days; range 2-1049 days for both). The median time for MDS until transformation to AML was 316 days (range: 15-6310 days). No difference with respect to outcome was detected between the four different molecular genetic subgroups. In conclusion, these data 1) show that NPM1 mutations play a major role in the evolution of AML following MDS or MPN. 2) NPM1 mutations can be the first as well as the second hit during transformation. 3) Support the theory of a multistep genetic principle in development of secondary AML. 4) s-AML with a NPM1+/FLT3-ITD- status can not be regarded as prognostically favorable. Disclosures: Schnittger: MLL Munich Leukemia Lab: Equity Ownership. Weiss:MLL Munich Leukemia Lab: Employment. Dicker:MLL Munich Leukemia Lab: Employment. Sundermann:MLL Munich Leukemia Lab: Employment. Kern:MLL Munich Leukemia Laboratory: Equity Ownership. Haferlach:MLL Munich Leukemia Lab: Equity Ownership. Haferlach:MLL Munich Leukemia Lab: Equity Ownership.

Impact of Additional Cytogenetic Alterations At Diagnosis on Prognosis of CML: Long-Term Observation From 1151 Patients of the Randomized CML Study IV

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 782-782
Author(s):  
Alice Fabarius ◽  
Armin Leitner ◽  
Andreas Hochhaus ◽  
Martin C Müller ◽  
Claudia Haferlach ◽  
...  
Keyword(s):  
Board Of Directors ◽  
Y Chromosome ◽  
Research Funding ◽  
Blast Crisis ◽  
Chronic Phase ◽  
Current Evidence ◽  
Prognostic Impact ◽  
Advisory Committees ◽  
Major Route ◽  
The Impact

Abstract Abstract 782 Introduction: Current evidence indicates that acquired genetic instability in chronic myeloid leukemia (CML) as a consequence of the t(9;22)(q34;q11) and the resulting BCR-ABL fusion causes the continuous acquisition of additional chromosomal aberrations (ACA) and mutations and thereby progression to accelerated phase and blast crisis (BC). Around 10 –12% of patients in chronic phase (CP) CML have ACA already at diagnosis. During the course of the disease this number rises to 80% in BC. Acquisition of ACA during treatment is considered as a poor prognostic indicator, whereas the impact of ACA at diagnosis is controversial. Patients and methods: Clinical and cytogenetic data of 1151 out of 1311 patients with Philadelphia and BCR-ABL positive CP CML randomized until 2009 to the German CML-Study IV were investigated in a prospective study. There were 459 females (40%) and 692 males (60%). Median age was 53 years (range, 16–88). All patients were treated with imatinib alone or in combination with interferon alpha or araC. The impact of ACA at diagnosis on time to complete cytogenetic and major molecular remission (CCR, MMR) and progression-free and overall survival (PFS, OS) was investigated. Written informed consent was obtained from all patients prior to entering the study. Results: At diagnosis 1003/1151 patients (87%) had the standard t(9;22)(q34;q11) only and 69 patients (6.0%) had a variant t(v;22). In 60 of 69 patients with t(v;22), only one further chromosome was involved in the translocation, in 7 patients two, and in 2 patients three further chromosomes were involved. Seventy-nine patients (6.9%) had ACA. Of these, 38 patients (3.3%) lacked the Y chromosome (-Y) and 41 patients (3.6%) had ACA except -Y. Sixteen of the 41 patients had major-route ACA (+8, i(17)(q10), +der(22)t(9;22)(q34;q11), ider(22)(q10)t(9;22)(q34;q11)) and 25 minor-route ACA [e.g. t(3;12), t(4;6), t(2;16), t(1;21)]. In patients with major-route ACA, trisomy 8 was the most frequent additional alteration (n=9). +der(22)t(9;22)(q34;q11) was observed in six patients, isochromosome (17)(q10) in five patients and ider(22)(q10)t(9;22)(q34;11) in three patients. After a median observation time of 5.3 years for patients with t(9;22), t(v;22), -Y, minor- and major-route ACA median times to CCR were 1.01, 0.95, 0.98, 1.49 and 1.51 years, to MMR 1.40, 1.58, 1.65, 2.49 and > 7 years, 5-year PFS 90%, 81%, 88%, 96% and 50% and 5-year OS 92%, 87%, 91%, 96% and 53%, respectively. In patients with major-route ACA times to CCR and MMR were longer. PFS and OS were shorter (p<0.001) than with standard t(9;22)(q34;q11). Loss of Y chromosome had no influence on time to CCR or MMR, PFS and OS. Conclusion: We conclude that the prognostic impact of additional cytogenetic findings at diagnosis of CML is heterogeneous and consideration of their types may be important. Major-route ACA identify a small group of patients with significantly poorer prognosis as compared to all other patients requiring early and more intensive intervention such as stem cell transplantation. Disclosures: Hochhaus: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Ariad: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Kneba:Hoffmann La Roche: Honoraria.

BCR-ABL Activates IGF-1 Expression and Signaling in Chronic Myelogenous Leukemia Blast Crisis Cell Lines.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1932-1932
Author(s):  
Elodie Pastural ◽  
Ashakumary Lakshmikuttyamma ◽  
Naoto Takahashi ◽  
Derek Pearson ◽  
David Sheridan ◽  
...  
Keyword(s):  
Growth Factor ◽  
Signaling Pathways ◽  
Cell Lines ◽  
Blast Crisis ◽  
Philadelphia Chromosome ◽  
Chronic Phase ◽  
Myelogenous Leukemia ◽  
Imatinib Treatment ◽  
Blocking Antibody ◽  
Receptor Blocking

Abstract CML blast crisis is characterized by the continued presence of the Philadelphia chromosome, which expresses the P210 BCR-ABL fusion protein, and the acquisition of additional molecular and chromosomal alterations. Evolution from CML chronic phase to blast crisis is associated with loss of heterozygosity at chromosome region 1p36, which contains the putative tumor suppressor RIZ1. We found that RIZ1 expression decreases during progression from CML chronic phase to myeloid blast crisis and that forced RIZ1 expression in CML blast crisis (CML-BC) cell lines decreases proliferation, increases apoptosis, and enhances differentiation. Furthermore, we found that RIZ1 represses IGF-1 autocrine production and blocks the activation of the IGF-1 receptor, AKT, and ERK signaling pathways in CML-BC cell lines thereby implicating RIZ1 control of the IGF-1 pathway in the regulation of these phenotypes. As BCR-ABL induces a growth factor independent phenotype due to the activation of autocrine growth factor production, we analyzed IGF-1 expression in CML-BC cell lines following exposure to imatinib. We found that imatinib treatment reduced IGF-1 mRNA and extracellular IGF-1 suggesting that RIZ1 may suppress blast crisis by counteracting the ability of BCR-ABL activate RIZ1 regulated genes. We characterized the signaling pathways used by BCR-ABL to activate IGF-1 expression and found that the HCK inhibitor PP2 and STAT5b shRNA reduced IGF-1 expression whereas the JAK2 inhibitor AG490 increased IGF-1 expression. These results suggest that BCR-ABL activates HCK, which in turn activates STAT5b and induces IGF-1 expression. To confirm the importance of BCR-ABL induced IGF-1 signaling to CML-BC cell line viability, proliferation and apoptosis, we characterized these cellular phenotypes in the presence of IGF-1 receptor blocking antibody and the IGF-1 receptor tyrosine kinase inhibitor AG1024. Blockage of autocrine IGF-1 signaling in CML-BC cell lines using an anti-IGF-1 receptor blocking antibody reduced cell viability and decreased proliferation. AG1024 treatment of CML-BC cell lines decreased proliferation and induced apoptosis. Together these results demonstrate that RIZ1 counteracts the ability of BCR-ABL to induce IGF-1 signaling in CML-BC cell lines, which influences cell proliferation, apoptosis, and differentiation. Our findings highlight RIZ-1 and IGF-1 signaling pathways as potential therapeutic targets for treating CML blast crisis.

Prevalence and Prognostic Impact of Allelic Imbalances Associated with Leukemic Transformation of Philadelphia Chromosome-Negative Myeloproliferative Neoplasms.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1280-1280
Author(s):  
Nils Heinrich Thoennissen ◽  
Utz O. Krug ◽  
Dhong Hyun Lee ◽  
Norohiko Kawamata ◽  
Terra L Lasho ◽  
...  
Keyword(s):  
Conflicts Of Interest ◽  
Myeloproliferative Neoplasms ◽  
Philadelphia Chromosome ◽  
Snp Array ◽  
Chronic Phase ◽  
Prognostic Impact ◽  
Genomic Alterations ◽  
Leukemic Transformation ◽  
Blast Phase ◽  
Hematopoietic Stem

Abstract Abstract 1280 Poster Board I-302 Philadelphia-chromosome negative myeloproliferative neoplasms (MPNs) including polycythemia vera (PV), essential thrombocytosis (ET), and primary myelofibrosis (PMF) are defined as clonal hematopoietic stem cell disorders. These disorders show an inherent tendency for transformation into leukemia (MPN-blast phase) which is hypothesized to be accompanied by acquisition of additional genomic lesions. We, therefore, obtained a comprehensive profile of genomic alterations associated with leukemic transformation by using single-nucleotide polymorphism (SNP) array in 88 MPN patients, as well as 71 cases with MPN-blast phase, and correlated these findings with their clinical parameters. A relatively high number of genomic alterations was found in MPN after leukemic transformation with 4.6 ± 0.6 abnormalities per sample compared to only 1.4 ± 0.2 changes per patient in chronic phase (p<0.001). Compared to the cytogenetic data, SNP-chip analysis detected about 47% additional chromosomal changes in the MPN samples, and 31% more in the MPN-blast phase cases, whereas SNP-array allelokaryotyping practically captured all cytogenetic abnormalities in our study population. Several additionally altered regions were detected in patients with MPN-blast phase compared to chronic phase, including both deletion and copy-number neutral-loss of heterozygosity (CNN-LOH) on chromosome 12p (9%) and 21q (9%), involving ETV6 and RUNX1. Notably, deletion and CNN-LOH on 17p involving TP53 were diagnosed in 18% of MPN-blast phase samples, which was highly associated with preceding treatment with alkylating agents (p=0.016). Moreover, trisomy 8, as well as amplification of 8q24.21 involving the MYC gene, were detected in 13% of patients with MPN-blast phase who were almost exclusively negative for the JAK2V617F mutation. Genome-wide inspection of further critical regions with promising new candidate genes involved in the evolution to the MPN-leukemic phase included deletion and CNN-LOH on 7q22.1 (SH2B2) in 18%, duplication/amplification on 19p13.2 (PIN1, ICAM1, CDC37) in 13% and 21q22.2 (ERG) in 9% of MPN patients with blast crisis. In contrast, we detected a decreased frequency of JAK2V617F in MPN-blast phase samples (52%) compared to chronic phase (71%). Also, the percentage of patients with homozygous mutant JAK2 as a result of CNN-LOH was lower in the MPN-blast phase (43%) compared to the chronic phase (53%). Taken together, the data suggest that gain-of-function mutation of JAK2 is not a perquisite for leukemic transformation. Remarkably, CNN-LOH on either 7q or 9p was related to decreased survival after leukemic transformation (p=0.02 and p=0.012, respectively). Given the variety of allelic imbalances, our data suggest that MPN-blast phase appears to be a heterogeneous disease prone to have evolved multiple mechanisms to provide a proliferative advantage to the abnormal leukemic clone. Our analysis of MPN genomes in the chronic compared to the leukemic stage provided new prognostic insights, as well as novel causative genes which might be involved in the transformation to MPN-blast phase. Disclosures No relevant conflicts of interest to declare.

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