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  • 1
    In: Blood, American Society of Hematology, Vol. 120, No. 21 ( 2012-11-16), p. 2411-2411
    Abstract: Abstract 2411 Forkhead Box P1 (FOXP1) is a member of the FOX family of transcription factors which play critical roles in immune responses, organ development and tumorigenesis. Multiple lines of evidence suggest that FOXP1 functions as an oncogene in B-cell neoplasms, being overexpressed in a variety of lymphomas and targeted by rare but recurrent translocations in marginal zone lymphoma (MZL) and diffuse large B-cell lymphoma (DLBCL). The most common translocation is t(3;14)(p13;q32) which brings FOXP1 under a transcriptional control of the IGH enhancers. Several cases with non-IG rearrangements of FOXP1 have been reported but thus far, not studied in details. Of note, Brown et al. (2008) demonstrated that FOXP1+ ABC-DLBCLs lacking FOXP1 rearrangements selectively express smaller N-truncated FOXP1 isoforms and subsequently hypothesized that the oncogenic role of FOXP1 is only exhibited by smaller isoforms. To unravel molecular consequences of non-IG aberrations of FOXP1 in lymphoma, we performed extensive FISH and molecular investigations of five cases harboring the rearrangements (index cases), complemented by studies of t(3;14)+ lymphoma and FOXP1+ and FOXP1-DLBCL/MZL. The index cases were presented with MZL, transforming MZL, CLL in Richter transformation and gastric DLBCL. The identified non-IG aberrations included t(2;3)(q36;p13), t(3;10)(p13;q24), inv(3)(p13q11) and an unknown IGH/IGK/IGL-negative translocation. One case displayed a microdeletion of FOXP1 spanning the region between exon 3 and 7, as shown by FISH and aCGH. The aberrations constituted a part of complex karyotypes and were subclonal in 3 cases. All tumors displayed a nuclear expression of the FOXP1 protein. FISH showed that the 3p13 breakpoints of index cases clustered within the coding region of FOXP1, contrasting with the 5' end breakpoints of a classical t(3;14)/IGH-FOXP1. Further FISH analysis of 3 available cases mapped the reciprocal breakpoints within AP1S3 (2q36) located in an opposite transcriptional orientation to FOXP1, in the 10q24 region harboring 3 genes (TMEM180- 〉 , C10orf95 〈 -, ACTRIA 〈 -), and in a gene poor region at 3q11, respectively. The applied 5'Race PCR additionally identified the PLEKHG1/FOXP1 fusion in one case of FOXP1+DLBCL. The fusion, however, occurred out of the reading frame of FOXP1 and was not functional. The pattern of FOXP1 expression was initially investigated using qRT-PCR. Both t(3;14)+cases, one FOXP1+DLBCL and non-malignant lymph nodes revealed an upregulation of all coding exons analyzed (6–18), while the index cases and the remaining FOXP1+DLBCLs displayed a significant upregulation of exons 7–18. Further RNA-sequencing of two index cases, 6 FOXP1+DLBCLs and 2 FOXP1-DLBCLs confirmed a general pattern of FOXP1 detected by qRT-PCR, and additionally identified several expressed FOXP1 isoforms. Their composition and a relative abundance differed in particular cases, but the most frequently expressed was the full length transcript and 3 N-truncated isoforms annotated by Ensembl as FOXP1–004, −203 and −009. The highest expression of the full length transcript was observed in cases with t(3;14) and FOXP1+GC-DLBCL; in the remaining cases a selective expression of N-truncated isoforms was noted. Results of transcriptomic studies were validated by Western analysis. Altogether, we showed that non-IG aberrations of FOXP1 are recurrent in B-cell lymphoma. These rearrangements are heterogeneous (reciprocal translocations, inversion, internal deletion) but constantly affect the coding part of the gene. They do not generate chimeric genes but result in an aberrant expression of N-truncated FOXP1 isoforms. Molecular mechanisms underlying these aberrations are largely unknown. Our findings suggest a dual role of FOXP1 in the pathogenesis of lymphoma: the full length FOXP1 upregulated by a primary IGH-mediated t(3;14) is a potent transforming factor implicated in development of lymphoma, while the N-truncated FOXP1 isoforms generated and activated by secondary non-IG aberrations, play a role in lymphoma progression. Of note, the latter variants are also overexpressed in ABC-DLBCL. Further studies of the wild type FOXP1 protein and N-truncated isoforms are required to demonstrate their oncogenic potential in vitro and in vivo. Disclosures: No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2012
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  • 2
    In: Blood, American Society of Hematology, Vol. 119, No. 23 ( 2012-06-07), p. 5367-5373
    Abstract: The clinical value of chemotherapy sensitization of acute myeloid leukemia (AML) with G-CSF priming has remained controversial. Cytarabine is a key constituent of remission induction chemotherapy. The effect of G-CSF priming has not been investigated in relationship with variable dose levels of cytarabine. We randomized 917 AML patients to receive G-CSF (456 patients) or no G-CSF (461 patients) at the days of chemotherapy. In the initial part of the study, 406 patients were also randomized between 2 cytarabine regimens comparing conventional-dose (199 patients) versus escalated-dose (207 patients) cytarabine in cycles 1 and 2. We found that patients after induction chemotherapy plus G-CSF had similar overall survival (43% vs 40%, P = .88), event-free survival (37% vs 31%, P = .29), and relapse rates (34% vs 36%, P = .77) at 5 years as those not receiving G-CSF. However, patients treated with the escalated-dose cytarabine regimen benefited from G-CSF priming, with improved event-free survival (P = .01) and overall survival (P = .003), compared with patients without G-CSF undergoing escalated-dose cytarabine treatment. A significant survival advantage of sensitizing AML for chemotherapy with G-CSF was not apparent in the entire study group, but it was seen in patients treated with escalated-dose cytarabine during remission induction. The HOVON-42 study is registered under The Netherlands Trial Registry (www.trialregister.nl) as #NTR230.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2012
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  • 3
    In: Blood, American Society of Hematology, Vol. 133, No. 13 ( 2019-03-28), p. 1457-1464
    Abstract: The prevention of relapse is the major therapeutic challenge in older patients with acute myeloid leukemia (AML) who have obtained a complete remission (CR) on intensive chemotherapy. In this randomized phase 3 study (HOVON97) in older patients (≥60 years) with AML or myelodysplastic syndrome with refractory anemia with excess of blasts, in CR/CR with incomplete hematologic recovery (CRi) after at least 2 cycles of intensive chemotherapy, we assessed the value of azacitidine as postremission therapy with respect to disease-free survival (DFS; primary end point) and overall survival (OS; secondary end point). In total, 116 eligible patients were randomly (1:1) assigned to either observation (N = 60) or azacitidine maintenance (N = 56; 50 mg/m2, subcutaneously, days 1-5, every 4 weeks) until relapse, for a maximum of 12 cycles. Fifty-five patients received at least 1 cycle of azacitidine, 46 at least 4 cycles, and 35 at least 12 cycles. The maintenance treatment with azacitidine was feasible. DFS was significantly better for the azacitidine treatment group (logrank; P = .04), as well as after adjustment for poor-risk cytogenetic abnormalities at diagnosis and platelet count at randomization (as surrogate for CR vs CRi; Cox regression; hazard ratio, 0.62; 95% confidence interval, 0.41-0.95; P = .026). The 12-month DFS was estimated at 64% for the azacitidine group and 42% for the control group. OS did not differ between treatment groups, with and without censoring for allogeneic hematopoietic cell transplantation. Rescue treatment was used more often in the observation group (n = 32) than in the azacitidine maintenance group (n = 9). We conclude that azacitidine maintenance after CR/CRi after intensive chemotherapy is feasible and significantly improves DFS. The study is registered with The Netherlands Trial Registry (NTR1810) and EudraCT (2008-001290-15).
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2019
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  • 4
    In: Blood, American Society of Hematology, Vol. 129, No. 12 ( 2017-03-23), p. 1636-1645
    Abstract: Clofarabine integrated in standard induction therapy for newly diagnosed AML reduces relapse probability but does not improve survival. Clofarabine improves survival in intermediate-risk AML categories ELN-1 and the AML genotype without NPM1 and without FLT3-ITD gene mutations.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2017
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  • 5
    In: Blood, American Society of Hematology, Vol. 124, No. 21 ( 2014-12-06), p. 1081-1081
    Abstract: Background: EVI1 gene overexpression is found in approximately 10% of acute myeloid leukemia (AML) patients, with a higher frequency seen in AML carrying chromosome 3q26 abnormality or MLL gene rearrangement, and associated with a dismal prognosis. Deregulation of EVI1 expression has also been reported in ALL, but its prognostic impact is unclear. Here, we retrospectively analyzed EVI1 expression in a large cohort of adult ALL patients, its correlation with ALL subsets, and its impact on patient outcome. Patients and Methods: EVI1 gene expression was measured by RQ-PCR detecting all splicing variants, with PBGD as control gene. We used dilutions of EVI1+ SKOV3 (kindly provided by Peter Valk, Rotterdam, The Netherlands) and EVI1-neg HL-60 cell line cDNA to build EVI1 and PBGD standard curves. Results were expressed as EVI1/PBGD ratio x 100. Blast samples from 354 patients treated in the GRAALL-2003/2005 and GRAAPH-2005 trials (191 B-cell precursor [BCP]-ALL, including 138 Ph-neg and 53 Ph+; 163 T-ALL) and 62 controls were analyzed. Immunophenotype results were centrally reviewed. In controls, median EVI1 expression level was 0.33% (Q1-Q3, 0.20-0.69). For prognostic analysis, we used the 1st and 99th percentiles of the controls (0.05% and 1.65%) to define patients with low and high EVI1 expression, respectively. Clinical endpoints were cumulative incidence of failure (CIF, failure meaning primary refractoriness or relapse) and event-free survival (EFS). Results: As illustrated in Figure 1, we observed that, as in one AML series, EVI1 expression may be up or down regulated in adult ALL. When compared to controls, the proportions of low and high EVI1 patients were 21 and 23% in Ph-neg BCP-ALL, 9 and 42% in Ph+ ALL, and 21 and 18% in T-ALL, respectively. In BCP-ALL patients, median EVI1 expression was similar to controls (0.53%; Q1-Q3, 0.11-1.88; p=0.15), but higher in the Ph+ as compared to the Ph-neg subgroup (0.93% versus 0.36%; p 〈 0.001). In T-ALL patients, median expression tended to be lower than in controls (0.22%; Q1-Q3, 0.06-0.85; p=0.058). In these three ALL subgroups, EVI1 expression did not correlate with age or WBC. Among Ph-neg BCP-ALL patients, a lower expression was found in MLL-AF4+ t(4;11) cases (median, 0.04%; p 〈 0.001), while no differences were observed for cases with t(1;19), an14q32, low hypodiploidy/near triploidy, complex karyotype, or IKZF1 deletion. Among T-ALL patients, a lower expression was found in cases with complex karyotype (median, 0.05%; p=0.03), while no differences were observed for cases with TLX1 overexpression, NOTCH1/FBXW7 mutation, N/K-RAS mutation or PTEN alteration. Only one patient had 3q26 abnormality (T-ALL with high EVI1 expression). Low or high EVI1 expression had no prognostic impact in Ph-neg as well as Ph+ BCP-ALL patients. In T-ALL, the proportion of patients with low EVI1 expression was more frequent in early and mature than in cortical T-ALL (33% and 33% vs 11%; p=0.002 and 0.028, respectively) and associated with a higher CIF (HR, 2.03; p=0.017) and shorter EFS (HR, 1.59; p=0.072). Low EVI1 expression was also significantly associated with an early T-cell precursor (ETP) phenotype (37.5% vs 18%; p=0.028). After adjustment on cortical and ETP phenotypes, as well as on 4-gene (NOTCH1/FBXW7/RAS/PTEN) genetic profiles, low EVI1 expression and high-risk genetic profiles remained independently associated with higher CIF (p=0.015 and 〈 0.001, respectively) and shorter EFS (p=0.045 and 0.002, respectively). Conclusion: Overall, these results confirm that EVI1 gene expression is frequently deregulated in adult ALL. In BCP-ALL, down-regulation is observed in t(4;11) and up-regulation in BCR-ABL cases. Further studies are needed to confirm that, in T-ALL, a lower expression is associated with the early, mature and ETP phenotypes and independently predictive of a worse patient outcome. Figure 1 Figure 1. EVI1 gene expression in ALL and control samples. Disclosures No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2014
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  • 6
    In: Blood, American Society of Hematology, Vol. 124, No. 21 ( 2014-12-06), p. 5194-5194
    Abstract: Peripheral T-cell lymphoma - not otherwise specified (PTCL-NOS) is the largest, most common and very heterogeneous category of PTCL. To date three PTCL variants have been described, including follicular variant (PTCL-F), a rare and poorly understood entity. Cytogenetically, PTCL-F is associated with a recurrent t(5;9)(q33;q22) resulting in the fusion of two protein tyrosine kinase (PTK) genes, ITK and SYK, showing constitutive activation of SYK. Transforming capacities of ITK-SYK were documented both in vitro and in vivo. Involvement of other PTK genes in the pathogenesis of PTCL-F has been postulated, but is thus far, not evidenced. We present cytogenetic, molecular and functional studies of two PTCL-F cases recently identified in our institution. The first case was characterized by complex chromosomal rearrangements involving several chromosomal regions harboring PTK genes. Extensive FISH analysis eventually identified FES involvement in t(15;16)(q26;q22). Further RNA-sequencing of this sample detected an in-frame fusion of exon 24 of RLTPR (16q22) to exon 11 of FES. The rearrangement was confirmed by subsequent Sanger sequencing of the 500 bp fragment obtained by RLTPR-FES nested RT-PCR. The predicted chimeric protein likely consists of the SH2 and Kinase domain of FES fused to the LRR domain of RLTPR. The second case showed a sole t(1;5)(p34;q21) masking the FER-involving inv(5)(q21q33) identified by FISH. By RNA-sequencing, an in-frame fusion of exon 8 of ITK/5q33 to exon 12 of FER/5q21 was identified. The rearrangement was confirmed by Sanger sequencing of the 402 bp fragment obtained by ITK-FER nested RT-PCR. The predicted chimeric protein likely contains the SH2 and Kinase domain of FER fused to a part of the SH2 domain of ITK. Oncogenic potential of RLTPR-FES was studied in vitro and in vivo. We designed a chimeric expression construct, introduced it into the murine hematopoietic IL3-dependent Ba/F3 cell line and showed that RLTPR-FES was able to transform Ba/F3 cells to growth factor-independent growth upon IL3 withdrawal. In addition, we demonstrated that NVP-TAE684, a small molecule ATP-competitive inhibitor of ALK and FES, abrogates the activity of the novel RLTPR-FES chimera. Western blot analysis confirmed a decrease of a phosphotyrosine protein of approximately 131kDa, corresponding to the predicted molecular weight of RLTPR-FES, with an increasing dose of NVP-TAE684 inhibitor. In vitro study of the ITK-FER fusion is ongoing. In order to assess the in vivo role of RLTPR-FES, a murine bone marrow transplantation model was established. Between 42-88 days after BMT, 4 mice transplanted with RLTPR-FES-transduced bone marrow developed a fatal disease and were sacrificed. Histological examination showed a massive infiltration of myeloid origin in all tissues examined (i.e. spleen, liver, thymus, bone marrow and lymph nodes). FACS analysis also confirmed this strong enrichment of cells of myeloid origin. Taken together, these data pointed toward the development of a myeloproliferative malignancy in all mice. Overall, our study confirms the critical role of PTKs in the pathogenesis of PTCL-F. In addition to SYK, we found FER and FES as targets of chromosomal aberrations in this tumor, and ITK, as a recurrent partner involved in the PTK fusions. Of note, FER and FES are the only two members of a distinct family of non-receptor PTKs, and thus far, their involvement in cancer-driving rearrangements has not been reported. Given that PTKs are ideal targets in the search for ‘molecularly-targeted’ cancer chemotherapy, PTCL-F patients may benefit from these novel therapeutic strategies. Disclosures No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2014
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  • 7
    In: Blood, American Society of Hematology, Vol. 124, No. 21 ( 2014-12-06), p. 542-542
    Abstract: Background. Allogeneic hematopoietic cell transplantation (allo-HCT) following nonmyeloablative conditioning is increasingly used as treatment for hematological malignancies in older patients or those with comorbidities. One of the most widely used nonmyeloablative conditioning associates fludarabine (90 mg/m² total dose) and 2 Gy total body irradiation (TBI) (Flu-TBI). This regimen can be safely performed in an outpatient setting but is associated with a relatively high incidence of graft-versus-host disease (GVHD). In an effort to prevent GVHD, the Stanford group have developed another nonmyeloablative conditioning that combines total lymphoid irradiation (TLI, 8 Gy total dose) with ATG (7.5 mg/kg Thymoglobulin® total dose) (TLI-ATG). As these 2 conditioning regimens have not been compared head to head, the Belgian Hematological Society (BHS)-transplantation committee initiated a phase II multicenter randomized study comparing nonmyeloablative allo-HCT with PBSC with either Flu-TBI (TBI arm) or TLI-ATG (TLI arm), and postgrafting immunosuppression with tacrolimus and mycophenolate mofetil. Here, we report the final analysis of the study. Methods. Patients were randomized 1/1 between TBI or TLI arm. Main inclusion criteria consisted of hematological malignancies not rapidly progressing, age ≤ 75 years of age, and having a HLA-identical sibling donor or 10/10 HLA-matched related or unrelated donors who is fit to donate PBSC. The primary endpoint was the 6-month incidence of grade II-IV acute GVHD. Results. 107 patients were randomized in the TBI (n=55) or TLI (n=52) arms between January 2008 and March 2011 in one of the 9 participating centers. Thirteen patients (6 in the TBI and 7 in the TLI arm) were excluded from the analyses because they did not meet the inclusion criteria at the time of the start of the conditioning (disease relapse before the start of the conditioning (n=5), ineligible for further irradiation (n=3), donor refusal to give PBSC (n=2), HLA-mismatched donor (n=2), and poor performance status (PS) precluding transplantation (n=1)). One patient randomized in the TBI arm received the TLI conditioning (and was analyzed in intention to treat in the TBI arm). Thus, the analysis includes data from 94 patients randomized to the TBI (n=49) or TLI (n=45) arm. The 2 groups were well balanced. Median follow-up for surviving patients was 45 (range, 19-65) months. The 180-day cumulative incidences of grade II-IV acute GVHD were 12.2% versus 8.9% in TBI and TLI patients, respectively (P=0.5). Two-year cumulative incidences of moderate/severe chronic GVHD were 40.8% versus 17.8% in TBI and TLI patients, respectively (P=0.017). Four-year cumulative incidences of relapse/progression were 22% and 50% in TBI and TLI patients, respectively (P=0.017). The difference remained statistically significant in multivariate analysis (HR=2.3, P=0.02). Four-year cumulative incidences of nonrelapse mortality were 24% and 13% in TBI and TLI patients, respectively (P=0.5). Finally, 4-year overall (OS) and progression-free survivals (PFS) were 53% and 54%, respectively, in the TBI arm, versus 54% (P=0.9) and 37% (P=0.12), respectively, in the TLI arm. Conclusions. In comparison to patients included in the TBI arm, patients included in the TLI arm had lower incidence of chronic GVHD, higher incidence of relapse and similar OS. The study was registered on ClinicalTrial.gov (NCT00603954). Disclosures Beguin: Genzyme / Sanofi: Research Funding. Baron:Genzyme / Sanofi: Honoraria, Research Funding.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2014
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  • 8
    In: Blood, American Society of Hematology, Vol. 122, No. 21 ( 2013-11-15), p. 5264-5264
    Abstract: Essential thrombocythemia (ET) is a myeloproliferative neoplasm featured by a sustained elevation of platelet count and a tendency for thrombosis and hemorrhage. Cytogenetic abnormalities are rare in ET. The most common molecular abnormality in ET is JAK2 V617F, found in approximately 50% of ET cases followed by MPL W515K/L, found in about 10% of cases. The molecular cause of the remaining ET cases is still largely unknown. As such, in a substantial fraction of ET cases, the underlying molecular cause is yet to be discovered. In a recent study by Hou et al., single cells derived from an ET JAK2 V617F-negative ET patient were sequenced using a method based on exome sequencing. Eight genes were identified as possible candidate drivers. However, their recurrence rate in ET was not established. Aims To establish the recurrence rate in JAK2 V617F-negative and MPL W515K/L-Negative ET of potential candidate driver mutations, as identified by Hou et al. Methods and Results We studied unfractionated blood or bone marrow samples from a series of 64 cases of JAK2 V617F-negative and MPL W515K/L-negative ET. In this series, we used PCR and Sanger sequencing to detect the following mutations: SESN2 P87S, TOP1MT S479L, ST13 Q349*, and DNAJC17 A292P, as they exhibited the highest scores in the study of Hou et al. In addition, we included NTRK1 N323S, a mutant tyrosine kinase. None of the mutations reported by Hou et al. was detected in our patients. However, we identified a novel acquired heterozygous mutation in TOP1MT (c.1400 A 〉 G, p.N467S) which is predicted to be damaging by polyphen 2. This mutation was not detected in the germline DNA from the buccal swab of the patient. TOP1MT is a mitochondrial topoisomerase encoded by the genomic DNA. It is a type IB enzyme, which sustains the appropriate conformation of DNA during replication, transcription, recombination, and repair. This mutation might affect the interaction of TOP1MT with the DNA molecule as suggested by the results of in silico analysis from I-Tasser. p.N467S mutation causes the gain of a helix and the loss of a β strand which are in close proximity to the bound DNA molecule. We screened exon 11 of TOP1MT gene in 38 additional JAK2 V617F-negative MPL W515K/L-negative ET cases, but did not find any additional cases. Conclusions In this series of 102 cases of JAK2 V617F-negative and MPL W515K/L-negative ET, only one case was identified with a mutation of TOP1MT. Mutations of SESN2, ST13, DNAJC17, or NTRK1, four other candidate driver genes as identified by Hou et al., could not be identified in a series of 64 cases. The functional role of TOP1MT in the pathogenesis of ET remains to be established. The absence of the mutations, as proposed by Hou et al., in our cohort raises questions about their role as potential driver mutations in JAK2 V617F-negative and MPL W515K/L-negative ET. The quest for the full complement of driver mutations in ET therefore remains open. Reference Hou, Y., et al., Single-cell exome sequencing and monoclonal evolution of a JAK2-negative myeloproliferative neoplasm. Cell, 2012. 148(5): p. 873-85. Disclosures: No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2013
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  • 9
    In: Blood, American Society of Hematology, Vol. 118, No. 21 ( 2011-11-18), p. 159-159
    Abstract: Abstract 159 AlloHSCT is considered standard consolidation therapy in adults with intermediate and poor-risk acute myeloid leukemia (AML) in first complete remission (CR1). Myeloablative (MAB) alloHSCT confers a survival advantage in younger AML patients (pts), but non-relapse mortality (NRM) may counterbalance a favorable effect on relapse, resulting in limited benefit in older pts. Meta-analyses have suggested that the advantage may already be limited beyond the age of 40. Reduced intensity conditioning (RIC) regimens were introduced to reduce NRM, while sparing graft versus leukemia (GVL) effects in older pts. Retrospective comparative studies have confirmed less NRM, but suggested that the net result in terms of overall outcome may not differ, as less NRM may be counterbalanced by more relapse. We evaluated within 4 consecutive prospective HOVON/SAKK cooperative studies (H29, H42, H42A, and H92) alloHSCT versus conventional consolidation in AML-CR1 pts between 40–60 years, with integrated comparison of alloHSCT using MAB versus RIC. Outcome measures included overall survival (OS), relapse free survival (RFS), as determined by relapse and NRM. The choice of conditioning regimen prior to alloHSCT (MAB or RIC) was solely based on center preference throughout the study period. 1105 pts between 40 and 60 years of age with newly diagnosed AML receiving consolidation in CR1, were studied, including 237 pts proceeding to MAB and 144 to RIC alloHSCT. 724 pts were consolidated with either a third cycle of chemotherapy (n=470) or an autograft (n=254). More pts with unfavourable karyotype or late CR proceeded to alloHSCT than to alternative consolidation. Recipients of MAB or RIC were comparable with respect to age, leukemia risk-status, donor/recipient gender combination, CMV-serology, time from diagnosis to HSCT, EBMT risk-score, and follow-up (median 24 versus 25 months, in RIC and MAB, respectively). Significant differences with respect to stem cell source, graft manipulation, and year of transplant were observed, with a higher proportion of RIC in recent years. Pts with alloHSCT showed better OS (55% ± 4) than pts receiving alternative consolidation (46% ±2), p 〈 0.01. In accordance with previous observations, pts in CR1, who received MAB alloHSCT had an OS of 50% (±3) at 5 years post HSCT, which appeared not different from consolidation by autografting, with OS of 49% (±3). However, pts receiving RIC alloHSCT experienced improved outcome with a 5 yr OS of 62% (±4%), p 〈 0.001, which improvement was noted among intermediate and poor-risk pts. RFS estimated 55% (±5%) versus 47% (±3%), in RIC and MAB pts, and RFS estimated 41% ±3% following autografting, p 〈 0.001. The 5 yr cumulative incidence of relapse was not significantly different between RIC and MAB conditioned pts (36% ±4% versus 29% ±3%, p=0.56), but recipients of RIC alloHSCT experienced significant less NRM (9% ±3% versus 24% ±3%, p 〈 0.001). Cox-regression analysis was performed with alloHSCT as a timedependent covariate and adjustment was done for age, time to CR, and cytogenetic risk. Comparing alloHSCT versus other consolidation treatments with respect to RFS, the overall hazard ratio (HR) for alloHSCT was 0.59 (95% CI, 0.49–0.70), P 〈 .0001, while specific HR's for RIC and MAB alloHSCT were 0.49 and 0.66, respectively, (both with p 〈 0.001). With endpoint OS, the overall HR for alloHSCT was 0.71 (95% CI, 0.76–0.90), p 〈 0.0001, while the HR for RIC was 0.53 (0.40–0.71), p 〈 0.001, and for MAB alloHSCT 0.82 (0.66–1.01), p=0.07. In addition, cytogenetic risk appeared an important risk factor, determining RFS and OS (HR 2.08 95%CI, 1.84–2.34, p 〈 0.0001). In conclusion, consolidation by alloHSCT significantly improves outcome as compared to either chemotherapy or autologous transplantation in CR1 pts aged 40–60 years, which was largely accounted for by RIC alloHSCT. These results suggest that: 1. similar to younger pts, alloHSCT can be considered standard consolidation therapy in intermediate and poor-risk AML in CR1, aged 40–60 years; 2. RIC and MAB alloHSCT may only slightly differ with respect to reduction of relapse in pts having benefited from intensive preceding induction/consolidation chemotherapy, while RIC is additionally associated with a significant reduction of NRM; 3. a prospective randomized trial comparing RIC and MAB in similarly pretreated AML pts, including younger pts in CR1, is advocated. Disclosures: Wijermans: Centocor Ortho Biotech Research & Development: Research Funding. Janssen:Novartis: Consultancy.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2011
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  • 10
    In: Blood, American Society of Hematology, Vol. 126, No. 23 ( 2015-12-03), p. 2837-2837
    Abstract: Introduction: The JAK2 p.V617F, MPL p.W515K/L and CALR indels occur in a mutually exclusive pattern in 80-90% of cases with Essential Thrombocythemia (ET), but the driver mutations are unknown in the remaining 10-20%. In this study we aimed to identify driver mutations in the latter group of triple negative (TN) ET by exome sequencing of 10 such cases. Results: We found 27 somatic variants, including indels, in 6 out of 10 TN ET patients (range: 1-10 mutations/case; mean: 2,7 mutations/case), none of which were recurrent. In one case, we found a MPL c.610T 〉 C (p.S204P) mutation, which is located in the extracellular domain of the MPLreceptor. By Sanger sequencing of MPL exon 4 in 20 additional TN ET cases, an additional patient with the MPL S204P mutation was identified. Moreover, this mutation was previously reported in one case with idiopathic myelofibrosis1. In order to study the effect of this mutation on the function of MPL, we produced stable Ba/F3 cell lines expressing MPL S204P, MPL W515K or MPL WT, and assessed the dependence of their growth on exogenous thrombopoietin (TPO). Only MPL W515K transduced Ba/F3 cells proliferated in the absence of TPO, but growth of MPL S204P Ba/F3 and of MPL WT Ba/F3 could be rescued by exogenous TPO, indicating the proper surface expression and the functionality of the transduced receptors. The levels of phospho-JAK2 and phospho-STAT5 were low in cytokine-deprived MPL S204P cells but increased upon TPO stimulation. In contrast, phospho-JAK2 and phospho-STAT5 were detectable in MPL W515K transduced Ba/F3 in the absence of cytokines as assessed by Western blotting. Culture of MPL S204P transduced Ba/F3 in the presence of TPO over a range of concentrations (0,01-10 ng/ml) yielded growth curves comparable with MPL WT transduced Ba/F3. Using flow cytometry, we also explored cell surface marker expression on peripheral blood platelets from the two MPL S204P ET patients. Data were compared with healthy donors or ET patients with JAK2 or CALR mutations. MPL S204P ET platelets displayed higher expression of CD61 than platelets from healthy donors or from JAK2 or CALR mutated ET (p 〈 0,01). In addition, there was a trend for higher expression of KIT, CD36 and CD42b on platelets from the MPL S204P ET cases. Moreover, following platelet activation through the protease activated receptor 1, the degranulation response of platelets from MPL S204P ET was decreased in comparison with JAK2 or CALR mutated ET. Conclusion: The MPL S204P mutation is a recurrent mutation in TN ET, with a frequency of 7% (2/30) in this series, but this mutation does not induce TPO-independent growth nor increased TPO-sensitivity in Ba/F3 cells. However, preliminary phenotypic and functional evidence supports the notion that MPL S204P platelets display specific characteristics as compared with JAK2 or CALR mutated ET. The mechanisms by which the MPL S204P mutation influences megakaryopoiesis and platelet function remain to be elucidated. 1. Williams DM, et al. Phenotypic variations and new mutations in JAK2 V617F-negative polycythemia vera, erythrocytosis, and idiopathic myelofibrosis. Exp Hematol 2007; 35: 1641. Disclosures Graux: Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2015
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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