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WT1 overexpression is frequently identified in acute myeloid leukemia (AML) and has been reported to be a potential marker for monitoring measurable residual disease (MRD). We evaluated the use of postinduction WT1 MRD level as a prognostic factor, as well as the interaction between postinduction WT1 MRD response and the effect of allogeneic stem cell transplantation (allo-SCT) in the first complete remission (CR). In the ALFA-0702 trial, patients with AML, aged 18 to 59, had a prospective quantification of WT1 MRD. The occurrence of a WT1 MRD ratio >2.5% in bone marrow or >0.5% in peripheral blood was defined as MRDhigh, and ratios below these thresholds were defined as MRDlow. The prognostic value of MRD after induction chemotherapy was assessed in 314 patients in first CR by comparing the risk of relapse, the relapse-free survival (RFS), and the overall survival (OS). Interaction between MRD response and the allo-SCT effect was evaluated in patients by comparing the influence of allo-SCT on the outcomes of patients with MRDhigh with those with MRDlow. The results showed that patients with MRDhigh after induction had a higher risk of relapse and a shorter RFS and OS. The MRD response remained of strong prognostic value in the subset of 225 patients with intermediate-/unfavorable-risk AML who were eligible for allo-SCT, because patients with MRDhigh had a significantly higher risk of relapse resulting in worse RFS and OS. The effect of allo-SCT was higher in patients with MRDlow than in those with MRDhigh, but not significantly different. The early WT1 MRD response highlights a population of high-risk patients in need of additional therapy.

The independent prognostic impact of specific dysplastic features in acute myeloid leukemia (AML) remains controversial and may vary between genomic subtypes. We apply a machine learning framework to dissect the relative contribution of centrally reviewed dysplastic features and oncogenetics in 190 patients with de novo AML treated in ALFA clinical trials. One hundred and thirty-five (71%) patients achieved complete response after the first induction course (CR). Dysgranulopoiesis, dyserythropoiesis and dysmegakaryopoiesis were assessable in 84%, 83% and 63% patients, respectively. Multi-lineage dysplasia was present in 27% of assessable patients. Micromegakaryocytes (q = 0.01), hypolobulated megakaryocytes (q = 0.08) and hyposegmented granulocytes (q = 0.08) were associated with higher ELN-2017 risk. Using a supervised learning algorithm, the relative importance of morphological variables (34%) for the prediction of CR was higher than demographic (5%), clinical (2%), cytogenetic (25%), molecular (29%), and treatment (5%) variables. Though dysplasias had limited predictive impact on survival, a multivariate logistic regression identified the presence of hypolobulated megakaryocytes (p = 0.014) and micromegakaryocytes (p = 0.035) as predicting lower CR rates, independently of monosomy 7 (p = 0.013), TP53 (p = 0.004), and NPM1 mutations (p = 0.025). Assessment of these specific dysmegakarypoiesis traits, for which we identify a transcriptomic signature, may thus guide treatment allocation in AML.

Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic stem cell disorder with overlapping features of myelodysplastic syndromes (MDS) and myeloproliferative neoplasms (MPN). Median overall survival of this aggressive myeloid malignancy is only 2-3 years, with a 15-30% risk of acute leukemic transformation. The paucity of clinical trials specifically designed for CMML has made therapeutic management of CMML patients challenging. As a result, treatment paradigms for CMML patients are largely borrowed from MDS and MPN. The standard of care still relies on hydroxyurea, hypomethylating agents (HMA), and allogeneic stem cell transplantation, this latter option remaining the only potentially curative therapy. To date, approved drugs for CMML treatment are HMA, including azacitidine, decitabine, and more recently the oral combination of decitabine and cedazuridine. However, HMA treatment does not meaningfully alter the natural course of this disease. New treatment approaches for improving CMML-associated cytopenias or targeting the CMML malignant clone are emerging. More than 25 therapeutic agents are currently being evaluated in phase 1 or phase 2 clinical trials for CMML and other myeloid malignancies, often in combination with a HMA backbone. Several novel agents, such as sotatercept, ruxolitinib, lenzilumab, and tagraxofusp have shown promising clinical efficacy in CMML. Current evidence supports the idea that effective treatment in CMML will likely require combination therapy targeting multiple pathways, which emphasizes the need for additional new therapeutic options. This review focuses on recent therapeutic advances and innovative treatment strategies in CMML, including global and molecularly targeted approaches. We also discuss what may help to make progress in the design of rationally derived and disease-modifying therapies for CMML.

Isocitrate dehydrogenase 1 (IDH1) and 2 (IDH2) mutations in Myeloid Neoplams (MNs) exhibit DNA hypermethylation via 2-hydroxyglutarate (2HG) over-production. Clinical impact of azacitidine (AZA) re...

High-risk myelodysplastic syndrome/acute myeloid leukemia patients have a very poor survival after azacitidine failure. Guadecitabine (SGI-110) is a novel subcutaneous hypomethylating agent which results in extended decitabine exposure. This multicenter phase II study evaluated the efficacy and safety of guadecitabine in high-risk myelodysplastic syndrome and low blast count acute myeloid leukemia patients refractory or relapsing after azacitidine. We included 56 patients with a median age of 75 years [Interquartile Range (IQR) 69-76]. Fifty-five patients received at least one cycle of guadecitabine (60 mg/m2/d subcutaneously days 1-5 per 28-day treatment cycles), with a median of 3 cycles (range, 0-27). Eight (14.3%) patients responded, including two complete responses; median response duration was 11.5 months. Having no or few identified somatic mutations was the only factor predicting response (P=0.035). None of the 11 patients with TP53 mutation responded. Median overall survival was 7.1 months, and 17.9 months in responders (3 of whom had overall survival >2 years). In multivariate analysis, IPSS-R (revised International Prognostic Scoring System) score other than very high (P=0.03) primary versus secondary azacitidine failure (P=0.01) and a high rate of demethylation in blood during the first cycle of treatment (P=0.03) were associated with longer survival. Thus, guadecitabine can be effective, sometimes yielding relatively prolonged survival, in a small proportion of high-risk myelodysplastic syndrome/low blast count acute myeloid leukemia patients who failed azacitidine. (Trial registered at clinicaltrials.gov identifier: 02197676).

Chronic myelomonocytic leukemia (CMML) is a rare, heterogeneous myeloid malignancy classified as a myelodysplastic syndromes/myeloproliferative neoplasm (MDS/MPN) overlap syndrome by the World Health Organization (WHO). Its initial presentation can be incidental or associated with myelodysplastic or myeloproliferative symptoms and up to 20% of patients harbor a concurrent inflammatory or autoimmune condition. Persistent monocytosis is the hallmark of CMML but diagnosis can be challenging. Increased understanding of human monocyte subsets, chromosomal abnormalities, and somatic gene mutations have led to more accurate diagnosis and improved prognostication. A number of risk stratification systems have been developed and validated but using those that incorporate molecular information such as CMML Prognostic Scoring System (CPSS)-Mol, Mayo Molecular, and Groupe Francophone des Myelodysplasies (GFM) are preferred. Symptom-directed approaches forms the basis of CMML management. Outcomes vary substantially depending on risk ranging from observation for a number of years to rapidly progressive disease and acute myeloid leukemia (AML) transformation. Patients who are low risk but with symptoms from cytopenias or proliferative features such as splenomegaly may be treated with hypomethylating agents (HMAs) or cytoreductive therapy, respectively, with the goal of durable symptoms control. Allogeneic hematopoietic cell transplantation should be considered for intermediate to high risk patients. The lack of effective pharmaceutical options has generated interest in novel therapeutics for this disease, and early phase clinical trial results are promising.

The inclusion of familial myeloid malignancies as a separate disease entity in the revised WHO classification has renewed efforts to improve the recognition and management of this group of at risk individuals. Here we report a cohort of 86 acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) families with 49 harboring germline variants in 16 previously defined loci (57%). Whole exome sequencing in a further 37 uncharacterized families (43%) allowed us to rationalize 65 new candidate loci, including genes mutated in rare hematological syndromes (ADA, GP6, IL17RA, PRF1 and SEC23B), reported in prior MDS/AML or inherited bone marrow failure series (DNAH9, NAPRT1 and SH2B3) or variants at novel loci (DHX34) that appear specific to inherited forms of myeloid malignancies. Altogether, our series of MDS/AML families offer novel insights into the etiology of myeloid malignancies and provide a framework to prioritize variants for inclusion into routine diagnostics and patient management., Familial myeloid malignancies have recently been classified as separate disease entities. Here, using whole-exome sequencing of affected pedigrees - the authors highlight genetic variants associated with these conditions.

Isolated trisomy 8 (+8) is a frequent cytogenetic abnormality in the myelodysplastic syndromes (MDS), but its characteristics are poorly reported. We performed a retrospective study of 138 MDS patients with isolated +8, classified or reclassified as MDS (excluding MDS/myeloproliferative neoplasm). Myeloproliferative (MP) features were defined by the repeated presence of one of the following: white blood cell count >10 × 109 /l, myelemia (presence of circulating immature granulocytes with a predominance of more mature forms) >2%, palpable splenomegaly. Fifty-four patients (39·1%) had MP features: 28 at diagnosis, 26 were acquired during evolution. MP forms had more EZH2 (33·3% vs. 12·0% in non-MP, P = 0·047), ASXL1 (66·7% vs. 42·3%, P = 0·048) and STAG2 mutations (77·8% vs. 21·7%, P = 0·006). Median event-free survival (EFS) and overall survival (OS) were 25 and 27 months for patients with MP features at diagnosis, versus 28 (P = 0·15) and 39 months (P = 0·085) for those without MP features, respectively. Among the 57 patients who received hypomethylating agent (HMA), OS was lower in MP cases (13 months vs. 23 months in non-MP cases, P = 0.02). In conclusion, MP features are frequent in MDS with isolated +8. MP forms had more EZH2, ASXL1 and STAG2 mutations, responded poorly to HMA, and tended to have poorer survival than non-MP forms.

Assessment of minimal residual disease has emerged as a powerful prognostic factor in acute myeloid leukemia. In this study, we investigated the potential of IDH1/2 mutations as targets for minimal residual disease assessment in acute myeloid leukemia, since these mutations collectively occur in 15-20% of cases of acute myeloid leukemia and now represent druggable targets. We employed droplet digital polymerase chain reaction assays to quantify IDH1R132, IDH2R140, and IDH2R172 mutations on genomic DNA in 322 samples from 103 adult patients with primary IDH1/2 mutant acute myeloid leukemia and enrolled on Acute Leukemia French Association (ALFA) - 0701 or -0702 clinical trials. The median IDH1/2 mutant allele fraction in bone marrow samples was 42.3% (range, 8.2 - 49.9%) at diagnosis of acute myeloid leukemia, and below the detection limit of 0.2% (range

Chromosomal rearrangements of the human MLL/KMT2A gene are associated with infant, pediatric, adult and therapy-induced acute leukemias. Here we present the data obtained from 2345 acute leukemia patients. Genomic breakpoints within the MLL gene and the involved translocation partner genes (TPGs) were determined and 11 novel TPGs were identified. Thus, a total of 135 different MLL rearrangements have been identified so far, of which 94 TPGs are now characterized at the molecular level. In all, 35 out of these 94 TPGs occur recurrently, but only 9 specific gene fusions account for more than 90% of all illegitimate recombinations of the MLL gene. We observed an age-dependent breakpoint shift with breakpoints localizing within MLL intron 11 associated with acute lymphoblastic leukemia and younger patients, while breakpoints in MLL intron 9 predominate in AML or older patients. The molecular characterization of MLL breakpoints suggests different etiologies in the different age groups and allows the correlation of functional domains of the MLL gene with clinical outcome. This study provides a comprehensive analysis of the MLL recombinome in acute leukemia and demonstrates that the establishment of patient-specific chromosomal fusion sites allows the design of specific PCR primers for minimal residual disease analyses for all patients.

Purpose: TP53 is a tumor-suppressor gene that functions as a regulator influencing cellular responses to DNA damage, and TP53 alterations are associated with pejorative outcome in most B-lymphoid disorders. Little is known regarding TP53 alteration in Waldenstrom's macroglobulinemia (WM). Experimental Design: Here, we have explored the incidence of TP53 alteration using Sanger sequencing and ultradeep-targeted sequencing in 125 WM and 10 immunoglobulin M (IgM) monoclonal gammopathy of undetermined significance (MGUS), along with the clinical features and the associated genomic landscape using single-nucleotide polymorphism array and mutational landscape in an integrative study. Results: Overall, we have identified alteration of TP53 locus including mutation, deletion, and copy-neutral LOH in 11.2% of WM. TP53 mutation was acquired in 7.3% of patients with WM at diagnosis, being absent in IgM MGUS, and was highly correlated to deletion 17p. No correlation with CXCR4 mutations was observed. Patients with TP53 alteration had a greater number of genomic abnormalities. Importantly, WM with TP53 alteration had a significantly shorter overall survival, particularly in symptomatic WM, and independently of the international prognostic scoring system for Waldenstrom macroglobulinemia (IPSSWM) score. Specific treatment for WM with TP53 may have to be studied. Nutlin-3a–targeted p53 signaling induced cytotoxicity preclinically, along with new compounds such as ibrutinib, PrimaMet, or CP31398 that bypass p53 pathway in WM, paving the path for future treatment-tailored options. Conclusions: Our results highlight the clinical significance of detection of TP53 alteration in WM to determine the prognosis of WM and guide the treatment choice. Clin Cancer Res; 23(20); 6325–35. ©2017 AACR.

Purpose This study assessed the prognostic impact of postinduction NPM1-mutated ( NPM1m) minimal residual disease (MRD) in young adult patients (age, 18 to 60 years) with acute myeloid leukemia, and addressed the question of whether NPM1m MRD may be used as a predictive factor of allogeneic stem cell transplantation (ASCT) benefit. Patients and Methods Among 229 patients with NPM1m who were treated in the Acute Leukemia French Association 0702 (ALFA-0702) trial, MRD evaluation was available in 152 patients in first remission. Patients with nonfavorable AML according to the European LeukemiaNet (ELN) classification were eligible for ASCT in first remission. Results After induction therapy, patients who did not achieve a 4-log reduction in NPM1m peripheral blood-MRD (PB-MRD) had a higher cumulative incidence of relapse (subhazard ratio [SHR], 5.83; P < .001) and a shorter overall survival (OS; hazard ratio [HR], 10.99; P < .001). In multivariable analysis, an abnormal karyotype, the presence of FLT3-internal tandem duplication (ITD), and a < 4-log reduction in PB-MRD were significantly associated with a higher relapse incidence and shorter OS. In the subset of patients with FLT3-ITD, only age, white blood cell count, and < 4-log reduction in PB-MRD, but not FLT3-ITD allelic ratio, remained of significant prognostic value. In these patients with nonfavorable AML according to European LeukemiaNet, disease-free survival and OS were significantly improved by ASCT in those with a < 4-log reduction in PB-MRD. This benefit was not observed in those with a > 4-log reduction in PB-MRD, with a significant interaction between ASCT effect and PB-MRD response ( P = .024 and .027 for disease-free survival and OS, respectively). Conclusion Our study supports the strong prognostic significance of early NPM1m PB-MRD, independent of the cytogenetic and molecular context. Moreover, NPM1m PB-MRD may be used as a predictive factor for ASCT indication.

The monitoring of the minimal residual disease by Wilms' tumor 1 expression (MRDWT1) is a standardized test, which can be used in over 80% of patients with AML. To investigate the prognostic value of MRDWT1 in patients undergoing allogeneic stem cell transplantation (allo-SCT) for AML, MRDWT1 was monitored 3 months after transplantation in 139 patients. MRDWT1 positivity did not lead to any therapeutic intervention. Median follow-up was 39.3 (6.4-99.8) months. Patients with positive MRDWT1 at 3 months experienced more often post-transplant relapse (27/30, 90%) than those with negative MRDWT1 (16/109, 14.7%) (P

Recent advances in genomic technologies have revolutionized acute myeloid leukemia (AML) understanding by identifying potential novel actionable genomic alterations. Consequently, current risk stratification at diagnosis not only relies on cytogenetics, but also on the inclusion of several of these abnormalities. Despite this progress, AML remains a heterogeneous and complex malignancy with variable response to current therapy. Although copy-number alterations (CNAs) are accepted prognostic markers in cancers, large-scale genomic studies aiming at identifying specific prognostic CNA-based markers in AML are still lacking. Using 367 AML, we identified four recurrent CNA on chromosomes 11 and 21 that predicted outcome even after adjusting for standard prognostic risk factors and potentially delineated two new subclasses of AML with poor prognosis. ERG amplification, the most frequent CNA, was related to cytarabine resistance, a cornerstone drug of AML therapy. These findings were further validated in The Cancer Genome Atlas data. Our results demonstrate that specific CNA are of independent prognostic relevance, and provide new molecular information into the genomic basis of AML and cytarabine response. Finally, these CNA identified two potential novel risk groups of AML, which when confirmed prospectively, may improve the clinical risk stratification and potentially the AML outcome.

The efficacy of azacitidine in patients with anemia and with lower-risk myelodysplastic syndromes, if relapsing after or resistant to erythropoietic stimulating agents, and the benefit of combining these agents to azacitidine in this setting are not well known. We prospectively compared the outcomes of patients, all of them having the characteristics of this subset of lower-risk myelodysplastic syndrome, if randomly treated with azacitidine alone or azacitidine combined with epoetin-β. High-resolution cytogenetics and gene mutation analysis were performed at entry. The primary study endpoint was the achievement of red blood cell transfusion independence after six cycles. Ninety-eight patients were randomised (49 in each arm). Median age was 72 years. In an intention to treat analysis, transfusion independence was obtained after 6 cycles in 16.3% versus 14.3% of patients in the azacitidine and azacitidine plus epoetin-β arms, respectively (P=1.00). Overall erythroid response rate (minor and major responses according to IWG 2000 criteria) was 34.7% vs. 24.5% in the azacitidine and azacitidine plus epoetin-β arms, respectively (P=0.38). Mutations of the SF3B1 gene were the only ones associated with a significant erythroid response, 29/59 (49%) versus 6/27 (22%) in SF3B1 mutated and unmutated patients, respectively, P=0.02. Detection of at least one “epigenetic mutation” and of an abnormal single nucleotide polymorphism array profile were the only factors associated with significantly poorer overall survival by multivariate analysis. The transfusion independence rate observed with azacitidine in this lower-risk population, but resistant to erythropoietic stimulating agents, was lower than expected, with no observed benefit of added epoetin, (clinicaltrials.gov identifier: 01015352).

Non-del(5q) transfusion-dependent low/intermediate-1 myelodysplastic syndrome (MDS) patients achieve an erythroid response with lenalidomide in 25% of cases. Addition of an erythropoiesis-stimulating agent could improve response rate. The impact of recurrent somatic mutations identified in the diseased clone in response to lenalidomide and the drug's effects on clonal evolution remain unknown. We investigated recurrent mutations by next-generation sequencing in 94 non-del(5q) MDS patients randomized in the GFM-Len-Epo-08 clinical trial to lenalidomide or lenalidomide plus epoetin β. Clonal evolution was analyzed after 4 cycles of treatment in 42 cases and reanalyzed at later time points in 18 cases. The fate of clonal architecture of single CD34(+)CD38(-) hematopoietic stem cells was also determined in 5 cases. Mutation frequency was >10%: SF3B1 (74.5%), TET2 (45.7%), DNMT3A (20.2%), and ASXL1 (19.1%). Analysis of variant allele frequencies indicated a decrease of major mutations in 15 of 20 responders compared with 10 of 22 nonresponders after 4 cycles. The decrease in the variant allele frequency of major mutations was more significant in responders than in nonresponders (P < .001). Genotyping of single CD34(+)CD38(-) cell-derived colonies showed that the decrease in the size of dominant subclones could be associated with the rise of founding clones or of hematopoietic stem cells devoid of recurrent mutations. These effects remained transient, and disease escape was associated with the re-emergence of the dominant subclones. In conclusion, we show that, although the drug initially modulates the distribution of subclones, loss of treatment efficacy coincides with the re-expansion of the dominant subclone. This trial was registered at www.clinicaltrials.gov as #NCT01718379.

EVI1 overexpression confers poor prognosis in acute myeloid leukemia (AML). Quantification of EVI1 expression has been mainly assessed by real-time quantitative PCR (RT-qPCR) based on relative quantification of EVI1-1D splice variant. In this study, we developed a RT-qPCR assay to perform quantification of EVI1 expression covering the different splice variants. A sequence localized in EVI1 exons 14 and 15 was cloned into plasmids that were used to establish RT-qPCR standard curves. Threshold values to define EVI1 overexpression were determined using 17 bone marrow (BM) and 31 peripheral blood (PB) control samples and were set at 1% in BM and 0.5% in PB. Samples from 64 AML patients overexpressing EVI1 included in the ALFA-0701 or -0702 trials were collected at diagnosis and during follow-up (n=152). Median EVI1 expression at AML diagnosis was 23.3% in BM and 3.6% in PB. EVI1 expression levels significantly decreased between diagnostic and post-induction samples, with an average variation from 21.6% to 3.56% in BM and from 4.0% to 0.22% in PB, but did not exceed 1 log10 reduction. Our study demonstrates that the magnitude of reduction in EVI1 expression levels between AML diagnosis and follow-up is not sufficient to allow sensitive detection of minimal residual disease.

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Somatic mutations contribute to the heterogeneous prognosis of chronic myelomonocytic leukemia (CMML). Hypomethylating agents (HMAs) are active in CMML, but analyses of small series failed to identify mutations predicting response or survival. We analyzed a retrospective multi-center cohort of 174 CMML patients treated with a median of 7 cycles of azacitidine (n = 68) or decitabine (n = 106). Sequencing data before treatment initiation were available for all patients, from Sanger (n = 68) or next generation (n = 106) sequencing. Overall response rate (ORR) was 52%, including complete response (CR) in 28 patients (17%). In multivariate analysis, ASXL1 mutations predicted a lower ORR (Odds Ratio [OR] = 0.85, p = 0.037), whereas TET2mut/ASXL1wt genotype predicted a higher CR rate (OR = 1.18, p = 0.011) independently of clinical parameters. With a median follow-up of 36.7 months, overall survival (OS) was 23.0 months. In multivariate analysis, RUNX1mut (Hazard Ratio [HR] = 2.00, p = .011), CBLmut (HR = 1.90, p = 0.03) genotypes and higher WBC (log10(WBC) HR = 2.30, p = .005) independently predicted worse OS while the TET2mut/ASXL1wt predicted better OS (HR = 0.60, p = 0.05). CMML-specific scores CPSS and GFM had limited predictive power. Our results stress the need for robust biomarkers of HMA activity in CMML and for novel treatment strategies in patients with myeloproliferative features and RUNX1 mutations., Highlights • TET2mut/ASXL1wt genotype predicts higher complete response rate and prolonged survival in CMML with hypomethylating agents. • Conversely, RUNX1mut and CBLmut genotypes are associated with poorer outcome, independently of higher leukocyte count. • CPSS and GFM prognostic scores showed modest performance when calculated at initiation of hypomethylating agents. Somatic mutations contribute to the heterogeneous prognosis of chronic myelomonocytic leukemia (CMML). Hypomethylating agents (HMAs) are active in CMML. Response and survival in MDS and AML patients treated with HMAs is difficult to predict. We explore the predictive role of recurrent somatic mutations in a large retrospective cohort of 174 HMA-treated CMMLs. Consistent with MDS studies, we report a higher response rate in TET2mut/ASXL1wt patients. We also identify a CMML-specific molecular pattern (RUNX1mut or CBLmut) associated with shorter survival. Our results can inform treatment decision in CMML, for instance by using HMAs prior to transplant in TET2mut/ASXL1wt patients.

Paraneoplastic leukemoid reaction (PLR), described in cancer patients, is defined as white blood cell (WBC) count higher than 40–50 G/L, predominantly composed of neutrophils and myeloid precursors...

Fil: Antony Debre, I.. Albert Einstein College of Medicine; Estados Unidos. Universite de Paris XI; Francia

// Jean-Emmanuel Bibault 1,3,* , Martin Figeac 2,3,* , Nathalie Helevaut 1 , Celine Rodriguez 1 , Sabine Quief 2,4 , Sheherazade Sebda 2,4 , Aline Renneville 1,3,5 , Olivier Nibourel 1,3,5 , Philippe Rousselot 6 , Berengere Gruson 7 , Herve Dombret 8 , Sylvie Castaigne 6 and Claude Preudhomme 1,3 1 Laboratory of Hematology, CHRU de Lille, France 2 Functional and Structural Genomic Platform, Lille, France 3 University of Lille Nord de France, Lille, France 4 Institut Pour la Recherche sur le Cancer de Lille, Lille, France 5 Inserm, UMR-S1172, Lille, France 6 Department of Hematology, Hopital de Versailles, Le Chesnay, Universite de Versailles-Saint Quentin, Versailles, France 7 Department of Hematology, CHU d’Amiens, Amiens, France 8 Department of Hematology, Hopital Saint Louis, AP-HP, Paris, France * These authors have contributed equally to this work Correspondence to: Claude Preudhomme, email: // Keywords : acute myeloid leukemia, FLT3 internal tandem duplication, minimal residual disease, next-generation sequencing Received : November 08, 2014 Accepted : May 25, 2015 Published : June 02, 2015 Abstract Minimal Residual Disease (MRD) detection can be used for early intervention in relapse, risk stratification, and treatment guidance. FLT3 ITD is the most common mutation found in AML patients with normal karyotype. We evaluated the feasibility of NGS with high coverage (up to 2.4.10 6 PE fragments) for MRD monitoring on FLT3 ITD. We sequenced 37 adult patients at diagnosis and various times of their disease (64 samples) and compared the results with FLT3 ITD ratios measured by fragment analysis. We found that NGS could detect variable insertion sites and lengths in a single test for several patients. We also showed mutational shifts between diagnosis and relapse, with the outgrowth of a clone at relapse different from that dominant at diagnosis. Since NGS is scalable, we were able to adapt sensitivity by increasing the number of reads obtained for follow-up samples, compared to diagnosis samples. This technique could be applied to detect biological relapse before its clinical consequences and to better tailor treatments through the use of FLT3 inhibitors. Larger cohorts should be assessed in order to validate this approach.

Acute myeloid leukemia (AML) with t(8;21) (q22;q22) is considered to have favorable risk; however, nearly half of t(8;21) patients are not cured, and recent studies have highlighted remarkable genetic heterogeneity in this subset of AML. Here we identify somatic mutations in additional sex combs-like 2 (ASXL2) in 22.7% (25/110) of patients with t(8;21), but not in patients with inv(16)/t(16;16) (0/60) or RUNX1-mutated AML (0/26). ASXL2 mutations were similarly frequent in adults and children t(8;21) and were mutually exclusive with ASXL1 mutations. Although overall survival was similar between ASXL1 and ASXL2 mutant t(8;21) AML patients and their wild-type counterparts, patients with ASXL1 or ASXL2 mutations had a cumulative incidence of relapse of 54.6% and 36.0%, respectively, compared with 25% in ASXL1/2 wild-type counterparts (P = .226). These results identify a high-frequency mutation in t(8;21) AML and identify the need for future studies to investigate the clinical and biological relevance of ASXL2 mutations in this unique subset of AML.

// Juliette Lambert 1 , Jerome Lambert 2 , Olivier Nibourel 3 , Cecile Pautas 4 , Sandrine Hayette 5 , Jean-Michel Cayuela 6 , Christine Terre 7 , Philippe Rousselot 1 , Herve Dombret 8 , Sylvie Chevret 9 , Claude Preudhomme 3 , Sylvie Castaigne 1 and Aline Renneville 3 1 Department of Hematology, Hopital de Versailles, Le Chesnay, Universite de Versailles-Saint Quentin; France 2 INSERM UMR-S 717, Paris; France 3 Laboratory of Hematology, CHRU de Lille; Universite de Lille Nord de France, Inserm, U837, Team 3, Cancer Research Institute of Lille, Lille; France 4 Department of Hematology, Hopital Henri Mondor, AP-HP, Creteil; France 5 Laboratory of Hematology, Centre Hospitalier Lyon-Sud, Hospices Civils de Lyon, UMR5239, Universite Claude Bernard, Lyon; France 6 Laboratory of Hematology, Hopital Saint-Louis, AP-HP, EA3518, University Paris Diderot, Paris; France 7 Laboratory of Cytogenetics, Hopital de Versailles, Le Chesnay; France 8 Department of Hematology, Hopital Saint Louis, AP-HP, Universite Paris Diderot, EA 3518, Paris; France 9 Department of Informatics and Biostatistics, Hopital Saint Louis, Universite Paris Diderot, INSERM S 717, Paris; France Correspondence: Juliette Lambert, email: // Keywords : minimal residual disease, gemtuzumab ozogamicin, acute myeloid leukemia, WT1 expression, NPM1 mutation Received : May 13, 2014 Accepted : July 07, 2014 Published : July 09, 2014 Abstract We analysed the prognostic significance of minimal residual disease (MRD) level in adult patients with acute myeloid leukemia (AML) treated in the randomized gemtuzumab ozogamicin (GO) ALFA-0701 trial. Levels of WT1 and NPM1 gene transcripts were assessed using cDNA-based real-time quantitative PCR in 183 patients with WT1 overexpression and in 77 patients with NMP1 mutation ( NPM1 mut) at diagnosis. Positive WT1 MRD (defined as > 0.5% in the peripheral blood) after induction and at the end of treatment were both significantly associated with a higher risk of relapse and a shorter overall survival (OS). Positive NPM1 mut MRD (defined as > 0.1% in the bone marrow) after induction and at the end of treatment also predicted a higher risk of relapse, but did not influence OS. Interestingly, the achievement of a negative NPM1 mut MRD was significantly more frequent in patients treated in the GO arm compared to those treated in control arm (39 % versus 7% (p=0.006) after induction and 91% versus 61% (p=0.028) at the end of treatment). However, GO did not influence WT1 MRD levels. Our study supports the prognostic significance of MRD assessed by WT1 and NPM1 mut transcript levels and show that NPM1 MRD is decreased by GO treatment.

// Thomas Cluzeau 1,2,3,4,6,* , Alix Dubois 1,2,3,4,* , Arnaud Jacquel 1,2,3,4 , Frederic Luciano 1,2,3,4 , Aline Renneville 5 , Claude Preudhomme 5 , Jean Michel Karsenti 6 , Nicolas Mounier 6 , Pierre Rohrlich 6 , Sophie Raynaud 7 , Bernard Mari 8 , Guillaume Robert 1,2,3,4 and Patrick Auberger 1,2,3,4,6 1 INSERM U1065, Mediterranean Center for Molecular Medicine (C3M), Nice, France 2 INSERM U1065, Team 2: Cell Death, Differentiation, Inflammation and Cancer 3 Equipe labellisee par la Ligue Nationale Contre le Cancer (2011-2013), Paris, France 4 University of Nice, Nice, France 5 Laboratory of Hematology, Biology and Pathology Center, CHRU of Lille, Lille, France 6 Department of Clinical hematology and Transplantation, CHU of Nice, Nice, France 7 Oncohematology laboratory, CHU of Nice, Nice, France 8 Molecular and Cellular Pharmacology Institute, CNRS, Sophia-Antipolis, France * These authors participated equally to this work Correspondence: Patrick Auberger, email: // Keywords : MDS, AML, Azacitidine, Polyploidy, TET2, ASLX1 Received : May 5, 2014 Accepted : May 26, 2014 Published : May 27, 2014 Abstract In the present study, we provide a comparative phenotypic and genotypic analysis of azacitidine-sensitive and resistant SKM-1 cell lines. Morphologically, SKM1-R exhibited increase in cell size that accounts for by enhanced ploidy in a majority of cells as shown by cell cycle and karyotype analysis. No specific Single Nucleotide Polymorphism (SNP) alteration was found in SKM1-R cells compared to their SKM1-S counterpart. Comparative pangenomic profiling revealed the up-regulation of a panel of genes involved in cellular movement, cell death and survival and down-regulation of genes required for cell to cell signaling and free radical scavenging in SKM1-R cells. We also searched for mutations frequently associated with myelodysplastic syndromes (MDS) and found that both cell lines harbored mutations in TET2, ASLX1 and TP53. Collectively, our data show that despite their different morphological and phenotypic features, SKM1-S and SKM1-R cells exhibited similar genotypic characteristics. Finally, pangenomic profiling identifies new potential pathways to be targeted to circumvent AZA-resistance. In conclusion, SKM1-R cells represent a valuable tool for the validation of new therapeutic intervention in MDS.

The SET-NUP214 (TAF1/CAN) fusion gene is a rare genetic event in T-cell acute lymphoblastic leukemia (T-ALL). Eleven (6%) of 196 T-ALL patients enrolled in the French Group for Research on Adult Acute Lymphoblastic Leukemia (GRAALL) 2003 and 2005 trials harbored a SET-NUP214 transcript. SET-NUP214-positive patients were predominantly (10 [91%] of 11) T-cell receptor (TCR)-negative and strikingly associated with TCRγδ lineage T-ALLs, as defined by expression of TCRγδ, TCRδ and/or TCRγ rearrangements but no complete TCRβ variable diversity joining rearrangement in surface CD3/TCR-negative cases. When compared with SET-NUP214-negative patients, SET-NUP214-positive patients showed a significantly higher rate of corticosteroid resistance (91% vs 44%; P = .003) and chemotherapy resistance (100% vs 44%; P = .0001). All SET-NUP214-positive patients but one achieved complete remission, and 9 were allografted. Despite the poor early-treatment sensitivity, the outcome of SET-NUP214-positive patients was similar to that of SET-NUP214-negative patients.

Although acute myeloid leukemia (AML) with t(8;21) belongs to the favorable risk AML subset, relapse incidence may reach 30% in those patients. RUNX1-RUNX1T1 fusion transcript is a well-established marker for minimal residual disease (MRD) monitoring. In this study, we investigated the feasibility and performances of RUNX1-RUNX1T1 DNA as MRD marker in AML with t(8;21). In 17/22 patients with t(8;21)-positive AML treated in the French CBF-2006 trial, breakpoints in RUNX1 and RUNX1T1 were identified using long-range PCR followed by next-generation sequencing. RUNX1-RUNX1T1 DNA quantification was performed by real-time quantitative PCR using patient-specific primers and probe. MRD levels were evaluated in 71 follow-up samples from 16 patients, with a median of four samples [range 2-7] per patient. RUNX1 breakpoints were located in intron 5 in all cases. RUNX1T1 breakpoints were located in intron 1b in 15 cases and in intron 1a in two cases. RUNX1-RUNX1T1 MRD levels measured on DNA and RNA were strongly correlated (r = 0.8, P < 0.0001). Discordant MRD results were observed in 10/71 (14%) of the samples: in three samples from two patients who relapsed, RUNX1-RUNX1T1 was detectable only on DNA, while RUNX1-RUNX1T1 was detectable only on RNA in seven samples. MRD monitoring on genomic DNA is feasible, but with sensitivity variations depending on the patient breakpoint sequence and the qPCR assay efficiency. Although interpretation of the results is easier because it is closely related to the number of leukemic cells, this method greatly increases time, cost and complexity, which limits its interest in routine practice.

Gemtuzumab ozogamicin (fGO), a humanized anti-CD33 monoclonal antibody linked to calicheamicin in combination with intensive chemotherapy gives high response rates in adult acute myeloid leukemia (AML) patients in relapse. However, reduced intensity chemotherapy in combination with fractionated GO has not been tested in aged relapsing patients. Patients from our institution with CD33+ AML aged 55 years or more in first late relapse (≥ 6 months) were proposed participation in a GO compassionate use program. Induction therapy consisted in fractionated GO (fGO; 3 mg/m², days 1, 4, 7) with standard-dose cytarabine (200 mg/m² /day, 7 days). Patients were consolidated with two courses of GO and intermediate dose cytarabine. Twenty-four patients (median age 68 years) received fGO with cytarabine. Median follow-up was 42 months. The response rate was 75%, including complete remission (CR) in 16 patients and CR with incomplete platelet recovery (CRp) in two patients. Two-year overall survival (OS) was 51% (95% CI: 28-69) and 2 years relapse-free survival (RFS) was 51% (95%CI: 25-72). Duration of second CR (CR2) was longer than first CR (CR1) in 9 out of 18 patients. Minimal residual disease (MRD) was negative in evaluable patients in CR2, particularly in NPM1 mutated cases. Toxicity was in line with that of the same fractionated single agent GO schedule. Fractionated GO with low intensity chemotherapy produced high response rates and prolonged CR2 in aged AML patients in first late relapse.

Mutation of the MYD88 gene has recently been identified in activated B-cell-like diffuse cell lymphoma and enhanced Janus kinase/signal transducer and activator of transcription (JAK-STAT) and nuclear factor κB (NF-κB) signaling pathways. A whole exome-sequencing study of Waldenstrom macroglobulinemia (WM) suggested a high frequency of MYD88 L265P mutation in WM. The genetic background is not fully deciphered in WM, although the role of NF-κB and JAK-STAT has been demonstrated. We analyzed MYD88 mutation in exon 5 and characterized the clinical significance of this genetic alteration in 67 WM patients. Clinical features; immunophenotypic markers; and conventional cytogenetic, fluorescence in situ hybridization, and single nucleotide polymorphism array data were analyzed. MYD88 L265P mutation was acquired in 79% of patients. Overall, we have identified alteration of the MYD88 locus in 91% of WM patients, including 12% with gain on chromosome 3 at the 3p22 locus that included the MYD88 gene. Patients with absence of MYD88 mutation were WM characterized with a female predominance, a splenomegaly, gain of chromosome 3, and CD27 expression. Importantly, inhibition of MYD88 signaling induced cytotoxicity and inhibited cell growth of cell lines issued from patients with WM. In conclusion, these results confirm a high frequency of MYD88 L265P mutation in WM. The discovery of MYD88 L265P mutation may contribute to a better understanding of the physiopathogeny of WM.

Germline heterozygous alterations of the tumor-suppressor gene neurofibromatosis-1 (NF1) lead to neurofibromatosis type 1, a genetic disorder characterized by a higher risk to develop juvenile myelomonocytic leukemia and/or acute myeloid leukemia (AML). More recently, somatic 17q11 deletions encompassing NF1 have been described in many adult myeloid malignancies. In this context, we aimed to define NF1 involvement in AML. We screened a total of 488 previously untreated de novo AML patients for the NF1 deletion using either array comparative genomic hybridization (aCGH) or real-time quantitative PCR/fluorescence in situ hybridization approaches. We also applied massively parallel sequencing for in depth mutation analysis of NF1 in 20 patients including five NF1-deleted patients. We defined a small ∼0.3 Mb minimal deleted region involving NF1 by aCGH and an overall frequency of NF1 deletion of 3.5% (17/485). NF1 deletion is significantly associated with unfavorable cytogenetics and with monosomal karyotype notably. We discovered six NF1 variants of unknown significance in 7/20 patients of which only one out of four disappeared in corresponding complete remission sample. In addition, only one out of five NF1-deleted patients has an acquired coding mutation in the remaining allele. In conclusion, direct NF1 inactivation is infrequent in de novo AML and may be a secondary event probably involved in leukemic progression.

In core binding factor (CBF) acute myeloid leukaemia (AML), realtime quantitative PCR is useful to quantify the fusion transcript ratio (CBFβ-MYH11 and AML1-ETO, in case of inv(16) and t(8;21) respectively) in peripheral blood and bone marrow during the courses of chemotherapy, in order to monitor minimal residual disease (MRD). In two cases of CBF AML associated with systemic mastocytosis (SM), the persistence of mast cells and the detection of a high ratio of fusion transcript, in bone marrow, during the courses of chemotherapy, led us to determine whether the mast cell component of the disease carried the same molecular alterations as leukaemic blasts. We demonstrate that sorted mast cells carried CBF abnormality. These observations point out the lack of specificity of MRD monitoring by RQ-PCR in these exceptional AML cases with SM. Moreover, this suggests that leukaemic blasts and mast cells derive from a common malignant progenitor.

Less than 50 patients with FPD/AML (OMIM 601309) have been reported as of today and there may an underestimation. The purpose of this study was to describe the natural history, the haematological features and the genotype-phenotype correlations of this entity in order to, first, screen it better and earlier, before leukaemia occurrence and secondly to optimize appropriate monitoring and treatment, in particular when familial stem cell transplantation is considered., We have investigated 41 carriers of RUNX1 alteration belonging to nine unrelated French families with FPD/AML and two syndromic patients, registered in the French network on rare platelet disorders from 2005 to 2015., Five missense, one non-sense, three frameshift mutations and two large deletions involving several genes including RUNX1 were evidenced. The history of familial leukaemia was suggestive of FPD/AML in seven pedigrees, whereas an autosomal dominant pattern of lifelong thrombocytopenia was the clinical presentation of two. Additional syndromic features characterized two large sporadic deletions. Bleeding tendency was mild and thrombocytopenia moderate (>50 x10(9)/L), with normal platelet volume. A functional platelet defect consistent with a δ-granule release defect was found in ten patients regardless of the type of RUNX1 alteration. The incidence of haematological malignancies was higher when the mutated RUNX1 allele was likely to cause a dominant negative effect (19/34) in comparison with loss of function alleles (3/9). A normal platelet count does not rule out the diagnosis of FPD/AML, since the platelet count was found normal for three mutated subjects, a feature that has a direct impact in the search for a related donor in case of allogeneic haematopoietic stem cell transplantation., Platelet dysfunction suggestive of defective δ-granule release could be of values for the diagnosis of FPD/AML particularly when the clinical presentation is an autosomal dominant thrombocytopenia with normal platelet size in the absence of familial malignancies. The genotype-phenotype correlations might be helpful in genetic counselling and appropriate optimal therapeutic management.

International audience; After failure of erythropoiesis-stimulating agents (ESAs), lenalidomide (LEN) yields red blood cell (RBC) transfusion independence (TI) in 20-30% of lower-risk non-del5q myelodysplastic syndrome (MDS). Several observations suggest an additive effect of ESA and LEN in this situation. We performed a randomized phase III study in 131 RBC transfusion-dependent (TD, median transfusion requirement six RBC units per 8 weeks) lower-risk ESA-refractory non-del5q MDS. Patients received LEN alone, 10 mg per day, 21 days per 4 weeks (L arm) or LEN (same schedule) + erythropoietin (EPO) beta, 60,000 U per week (LE arm). In an intent-to-treat (ITT) analysis, erythroid response (HI-E, IWG 2006 criteria) after four treatment cycles (primary end point) was 23.1% (95% CI 13.5-35.2) in the L arm and 39.4% (95% CI 27.6-52.2) in the LE arm (P=0.044), while RBC-TI was reached in 13.8 and 24.2% of the patients in the L and LE arms, respectively (P=0.13). Median response duration was 18.1 and 15.1 months in the L and LE arms, respectively (P=0.47). Side effects were moderate and similar in the two arms. Low baseline serum EPO level and a G polymorphism of CRBN gene predicted HI-E. Combining LEN and EPO significantly improves erythroid response over LEN alone in lower-risk non-del5q MDS patients with anemia resistant to ESA

In t(8;21)(q22;q22) acute myeloid leukemia, the prognostic value of early minimal residual disease assessed with real-time quantitative polymerase chain reaction is the most important prognostic factor, but how long-term minimal residual disease monitoring may contribute to drive individual patient decisions remains poorly investigated. In the multicenter CBF-2006 study, a prospective monitoring of peripheral blood and bone marrow samples was performed every 3 months and every year, respectively, for 2 years following intensive chemotherapy in 94 patients in first complete remission. A complete molecular remission was defined as a (RUNX1-RUNX1T1/ABL1)×100 ≤ 0.001%. After the completion of consolidation therapy, a bone marrow complete molecular remission was observed in 30% of the patients, but was not predictive of subsequent relapse. Indeed, 8 patients (9%) presented a positive bone marrow minimal residual disease for up to 2 years of follow-up while still remaining in complete remission. Conversely, a peripheral blood complete molecular remission was statistically associated with a lower risk of relapse whatever the time-point considered after the completion of consolidation therapy. During the 2-year follow-up, the persistence of peripheral blood complete molecular remission was associated with a lower risk of relapse (4-year cumulative incidence, 8.2%), while molecular relapse confirmed on a subsequent peripheral blood sample predicted hematological relapse (4-year cumulative incidence, 86.9%) within a median time interval of 3.9 months. In t(8;21)(q22;q22) acute myeloid leukemia, minimal residual disease monitoring on peripheral blood every 3 months allows for the prediction of hematological relapse, and to identify patients who could potentially benefit from intervention therapy. (ClinicalTrials.gov ID #NCT00428558).

Additional sex combs-like (ASXL) genes are human homologues of the Drosophila-Asx gene encoding proteins that control gene expression through the regulation and the recruitment of epigenetic regula...

International audience; Approximately 30% of the patients who fulfil the criteria of Waldenström's macroglobulinemia (WM) are diagnosed while asymptomatic (indolent), and will not require immediate therapy. Conversely, patients with a disease-related event will be considered for therapy. The physiopathology of these 2 groups remains unclear, and the mechanisms of progression from indolent to symptomatic WM have yet to be fully understood. Seventeen patients diagnosed with WM were included in this study, 8 asymptomatic WM (A-WM) and 9 symptomatic WM (S-WM). A differential analysis was performed on a first series of 11 patients and identified 48 genes whose expression separated samples from A-to S-WM. This gene signature was then confirmed on a second independent validation set of 6 WM. Within this expression profile, BACH2, a B-cell transcription factor known to be a tumor suppressor gene, was found to be over-expressed in A-MW relatively to S-MW. We specifically over-expressed BACH2 in a WM-related cell line and observed a significant reduction of the clonogenic activity. To the best of our knowledge, we report for the first time a specific gene expression signature that differentiates A-WM and S-WM. Within this expression profile, BACH2 was identified as a candidate gene that may help to understand better the behavior of tumor cells in indolent WM.

RUNX1 gene alterations are associated with acquired and inherited hematologic malignancies that include familial platelet disorder/acute myeloid leukemia, primary or secondary acute myeloid leukemia, and chronic myelomonocytic leukemia. Recently, we reported that RUNX1-mediated silencing of nonmuscle myosin heavy chain IIB (MYH10) was required for megakaryocyte ploidization and maturation. Here we demonstrate that runx1 deletion in mice induces the persistence of MYH10 in platelets, and a similar persistence was observed in platelets of patients with constitutional (familial platelet disorder/acute myeloid leukemia) or acquired (chronic myelomonocytic leukemia) RUNX1 mutations. MYH10 was also detected in platelets of patients with the Paris-Trousseau syndrome, a thrombocytopenia related to the deletion of the transcription factor FLI1 that forms a complex with RUNX1 to regulate megakaryopoiesis, whereas MYH10 persistence was not observed in other inherited forms of thrombocytopenia. We propose MYH10 detection as a new and simple tool to identify inherited platelet disorders and myeloid neoplasms with abnormalities in RUNX1 and its associated proteins.

A cohort of MDS patients was examined for mutations affecting 4 splice genes (SF3B1, SRSF2, ZRSR2, and U2AF35) and evaluated in the context of clinical and molecular markers. Splice gene mutations were detected in 95 of 221 patients. These mutations were mutually exclusive and less likely to occur in patients with complex cytogenetics or TP53 mutations. SF3B1mut patients presented with lower hemoglobin levels, increased WBC and platelet counts, and were more likely to have DNMT3A mutations. SRSF2mut patients clustered in RAEB-1 and RAEB-2 subtypes and exhibited pronounced thrombocytopenias. ZRSR2mut patients clustered in International Prognostic Scoring System intermediate-1 and intermediate-2 risk groups, had higher percentages of bone marrow blasts, and more often displayed isolated neutropenias. SRSF2 and ZRSR2 mutations were more common in TET2mut patients. U2AF35mut patients had an increased prevalence of chromosome 20 deletions and ASXL1 mutations. Multivariate analysis revealed an inferior overall survival and a higher AML transformation rate for the genotype ZRSR2mut/TET2wt (overall survival: hazard ratio = 3.3; 95% CI, 1.4-7.7; P = .006; AML transformation: hazard ratio = 3.6; 95% CI, 2-4.2; P = .026). Our results demonstrate that splice gene mutations are among the most frequent molecular aberrations in myelodysplastic syndrome, define distinct clinical phenotypes, and show preferential associations with mutations targeting transcriptional regulation.

FLT3 internal tandem duplication (FLT3-ITD) is usually considered as a bad marker for minimal residual disease (MRD) follow-up in acute myeloid leukemia (AML). Our objective was to evaluate the suitability of FLT3-ITD as a target for MRD detection by real-time quantitative PCR, in comparison with two other molecular MRD markers, NPM1 mutation and WT1 overexpression, in 20 adult AML patients treated in Acute Leukemia French Association (ALFA) trials. Overall, these 3 MRD markers showed comparable kinetics in 17/20 (85%) cases. Furthermore, we found that FLT3-ITD MRD levels after induction chemotherapy are predictive of complete remission duration.

Acute myeloid leukemia (AML) with t(8;21) or inv(16) have been recognized as unique entities within AML and are usually reported together as core binding factor AML (CBF-AML). However, there is considerable clinical and biological heterogeneity within this group of diseases, and relapse incidence reaches up to 40%. Moreover, translocations involving CBFs are not sufficient to induce AML on its own and the full spectrum of mutations coexisting with CBF translocations has not been elucidated. To address these issues, we performed extensive mutational analysis by high-throughput sequencing in 215 patients with CBF-AML enrolled in the Phase 3 Trial of Systematic Versus Response-adapted Timed-Sequential Induction in Patients With Core Binding Factor Acute Myeloid Leukemia and Treating Patients with Childhood Acute Myeloid Leukemia with Interleukin-2 trials (age, 1-60 years). Mutations in genes activating tyrosine kinase signaling (including KIT, N/KRAS, and FLT3) were frequent in both subtypes of CBF-AML. In contrast, mutations in genes that regulate chromatin conformation or encode members of the cohesin complex were observed with high frequencies in t(8;21) AML (42% and 18%, respectively), whereas they were nearly absent in inv(16) AML. High KIT mutant allele ratios defined a group of t(8;21) AML patients with poor prognosis, whereas high N/KRAS mutant allele ratios were associated with the lack of KIT or FLT3 mutations and a favorable outcome. In addition, mutations in epigenetic modifying or cohesin genes were associated with a poor prognosis in patients with tyrosine kinase pathway mutations, suggesting synergic cooperation between these events. These data suggest that diverse cooperating mutations may influence CBF-AML pathophysiology as well as clinical behavior and point to potential unique pathogenesis of t(8;21) vs inv(16) AML.

Purpose: Whole-genome sequencing has revealed MYD88 L265P and CXCR4 mutations (CXCR4mut) as the most prevalent somatic mutations in Waldenström macroglobulinemia. CXCR4 mutation has proved to be of critical importance in Waldenström macroglobulinemia, in part due to its role as a mechanism of resistance to several agents. We have therefore sought to unravel the different aspects of CXCR4 mutations in Waldenström macroglobulinemia. Experimental Design: We have scanned the two coding exons of CXCR4 in Waldenström macroglobulinemia using deep next-generation sequencing and Sanger sequencing in 98 patients with Waldenström macroglobulinemia and correlated with SNP array landscape and mutational spectrum of eight candidate genes involved in TLR, RAS, and BCR pathway in an integrative study. Results: We found all mutations to be heterozygous, somatic, and located in the C-terminal domain of CXCR4 in 25% of the Waldenström macroglobulinemia. CXCR4 mutations led to a truncated receptor protein associated with a higher expression of CXCR4. CXCR4 mutations pertain to the same clone as to MYD88 L265P mutations but were mutually exclusive to CD79A/CD79B mutations (BCR pathway). We identified a genomic signature in CXCR4mut Waldenström macroglobulinemia traducing a more complex genome. CXCR4 mutations were also associated with gain of chromosome 4, gain of Xq, and deletion 6q. Conclusions: Our study panned out new CXCR4 mutations in Waldenström macroglobulinemia and identified a specific signature associated to CXCR4mut, characterized with complex genomic aberrations among MYD88L265P Waldenström macroglobulinemia. Our results suggest the existence of various genomic subgroups in Waldenström macroglobulinemia. Clin Cancer Res; 22(6); 1480–8. ©2015 AACR.

Fetal hemoglobin (HbF, α2γ2) induction is a well-validated strategy for sickle cell disease (SCD) treatment. Using a small-molecule screen, we found that UNC0638, a selective inhibitor of EHMT1 and EHMT2 histone methyltransferases, induces γ-globin expression. EHMT1/2 catalyze mono- and dimethylation of lysine 9 on histone 3 (H3K9), raising the possibility that H3K9Me2, a repressive chromatin mark, plays a role in silencing γ-globin expression. In primary human adult erythroid cells, UNC0638 and EHMT1 or EHMT2 short hairpin RNA-mediated knockdown significantly increased γ-globin expression, HbF synthesis, and the percentage of cells expressing HbF. At effective concentrations, UNC0638 did not alter cell morphology, proliferation, or erythroid differentiation of primary human CD34(+) hematopoietic stem and progenitor cells in culture ex vivo. In murine erythroleukemia cells, UNC0638 and Ehmt2 CRISPR/Cas9-mediated knockout both led to a marked increase in expression of embryonic β-globin genes Hbb-ey and Hbb-βh1. In primary human adult erythroblasts, chromatin immunoprecipitation followed by sequencing analysis revealed that UNC0638 treatment leads to genome-wide depletion in H3K9Me2 and a concomitant increase in the activating mark H3K9Ac, which was especially pronounced at the γ-globin gene region. In RNA-sequencing analysis of erythroblasts, γ-globin genes were among the most significantly upregulated genes by UNC0638. Further increase in γ-globin expression in primary human adult erythroid cells was achieved by combining EHMT1/2 inhibition with the histone deacetylase inhibitor entinostat or hypomethylating agent decitabine. Our data provide genetic and pharmacologic evidence that EHMT1 and EHMT2 are epigenetic regulators involved in γ-globin repression and represent a novel therapeutic target for SCD.

To assess the value of administering timed-sequential chemotherapy (TSC) (two therapeutic sequences separated by a four-day interval-free chemotherapy) or high-dose cytarabine (HDAraC) cycles in consolidation therapy for acute myeloid leukemia (AML), 459 patients aged 15 to 50 years were enrolled in the prospective randomized Acute Leukemia French Association-9802 trial. Complete remission was achieved in 89%. Two hundred and thirty seven patients were then randomized to either TSC consolidation (120 patients) or HDAraC consolidation cycles (117 patients). Overall, there was no significant difference between the two consolidation arms (5-year event-free survival (EFS): 41% for HDAraC vs 35% for TSC), or cumulative incidence of relapse, or treatment-related mortality. Cytogenetically normal AML (CN-AML) NPM1 + or CEBPA + and FLT3-ITD - had the same outcome as those with favorable cytogenetics. When considering favorable and unfavorable risk groups, the trend was in favor of HDAraC. However, the difference became significant when considering intermediate cytogenetics (5-year EFS: 49% vs 29%; p = 0.02), especially CN-AML (5-year EFS: 48% vs 31%; p = 0.04), which was related to lower relapse rate and less toxicity. This study demonstrates that TSC did not produce any benefit when used as consolidation therapy in younger adult as compared to HDAraC. This trial is registered at www.clinicaltrials.gov as no. [NCT00880243][1]. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00880243&atom=%2Fbloodjournal%2Fearly%2F2011%2F06%2F20%2Fblood-2011-04-349258.atom

Le gene Wilms’ Tumor 1 ( WT1), localise sur le chromosome 11p13, code pour une proteine regulatrice de la transcription. Initialement decouvert du fait de son alteration dans la tumeur de Wilms, le gene WT1 s’est avere etre aussi implique dans les hemopathies malignes, en particulier les leucemies aigues (LA). Le role de WT1 dans les LA a ete souligne par la presence d’une surexpression de WT1 dans 60 a 90 % des cas et de mutations de WT1 dans environ 10 % des cas. Bien que la contribution de WT1 a la leucemogenese reste a preciser, les applications cliniques et therapeutiques des alterations de WT1 dans les LA prennent une importance croissante. L’interet de la surexpression de WT1 comme marqueur pour le suivi de la maladie residuelle est aujourd’hui reconnu dans les LA myeloides. Plusieurs etudes ont montre l’impact pronostique de l’evaluation quantitative de l’expression de WT1 en suivi et sa capacite a detecter precocement les rechutes. De plus, la valeur pronostique des mutations de WT1 dans les LA pourrait contribuer a ameliorer la stratification therapeutique des patients. Enfin, la proteine WT1 constitue une cible tres attractive pour le developpement de strategies de vaccinations, ce qui ouvre de nouvelles perspectives therapeutiques pour les patients atteints de LA.