flow-cytometry-to-estimate-leukemia-stem-cells-primary-acute-myeloid

Flow Cytometry to Estimate Leukemia Stem Cells in Primary Acute Myeloid Leukemia and in Patient-derived-xenografts, at Diagnosis and Follow Up

Acute myeloid leukemia (AML) is a heterogeneous, and if not treated, fatal disease. It is the most common cause of leukemia-associated mortality in ...

multicenter-flow-cytometry-for-acute-myeloid-leukemia-measurable

Multicenter Flow Cytometry For Acute Myeloid Leukemia Measurable Residual Disease With LAIP/DfN And CD34<sup>+</sup>CD38<sup>-</sup> Leukemic Stem Cell-Enriched Populations

Measurable residual disease (MRD) follow-up is recommended for treatment response evaluation in acute myeloid leukemia (AML) clinical trials according to ...

CHU Lille

Univ. Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc - Centre de Recherche Jean-Pierre AUBERT Neurosciences et Cancer

CHU-Lille

UNIVERSITY OF LILLE

The core-binding factor (CBF) complex is a heterodimeric transcription factor composed of 2 subunits, CBFalpha and CBFbeta, that play a major role in hematopoiesis. Both members of the CBF complex are frequently altered in acute myeloid leukemia (AML) by translocation, most commonly t(8;21), t(12;21), and t(3;21) for CBFalpha, located in 21q22, and inv(16)(p13;q22) for CBFbeta, located on 16q22. Recently, a new mechanism of alteration of CBFalpha, by point mutation, has been reported in myeloid malignancies, particularly in M0 AML. In the present study, we found no point mutation of the CBFbeta gene in 30 myelodysplastic syndromes and 100 AMLs, suggesting a limited role, if any, of CBFbeta point mutations in those disorders.

Unlike AML1, CBFbeta gene is not deregulated by point mutations in acute myeloid leukemia and in myelodysplastic syndromes.

Mutations of the AML1 gene are frequent molecular abnormalities in minimally differentiated acute myeloblastic leukemia (M0 AML), a rare type of AML. In this retrospective multicenter study, morphologic, immunophenotypical, cytogenetic, and molecular features of 59 de novo M0 AML cases were analyzed and correlated to AML1 mutations. Point mutations of AML1 gene were observed in 16 cases (27%). They were correlated with higher white blood cell (WBC) count (P =.001), greater marrow blast involvement (P =.03), higher incidence of immunoglobulin H/T-cell receptor (IgH/TCR) gene rearrangement (P <.0001), and with a borderline significant lower incidence of complex karyotypes. In the 59 patients, FLT3 mutations were the only significant prognostic factors associated with short survival.

M0 AML, clinical and biologic features of the disease, including AML1 gene mutations: a report of 59 cases by the Groupe Français d'Hématologie Cellulaire (GFHC) and the Groupe Français de Cytogénétique Hématologique (GFCH).

Myelodysplastic syndromes (MDS) are clonal malignant stem cell disorders characterized by inefficient hematopoiesis. The role of the marrow microenvironment in the pathogenesis of the disease has been controversial and no study has been performed so far to characterize mesenchymal cells (MC) from MDS patients and to analyse their ability to support hematopoiesis. To this end, we have isolated and characterized MC at diagnostic marrow samples (n=12) and have purified their CD34+CD38- and CD34+CD38+ counterparts (n=7) before using MC as a short- and long-term hematopoietic support. We show that MC can be readily isolated from MDS marrow and exhibit a major expansion potential as well as an intact osteoblastic differentiation ability. They do not harbor the abnormal marker identified by FISH in the hematopoietic cells and they stimulate the growth of autologous clonogenic cells. Conversely, highly purified stem cells and their cytokine-expanded progeny harbor the clonal marker with variable frequencies, and both normal and abnormal long-term culture-initiating cell-derived progeny can be effectively supported by autologous MC. Thus, we demonstrate that MDS marrow is an abundant source of MC appearing both cytogenetically and functionally noninvolved by the malignant process and able to support hematopoiesis, suggesting their possible usefulness in future cell therapy approaches.

Mesenchymal cells generated from patients with myelodysplastic syndromes are devoid of chromosomal clonal markers and support short- and long-term hematopoiesis in vitro.

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.

Involvement of a common progenitor cell in core binding factor acute myeloid leukaemia associated with mastocytosis.

Linezolid induces ring sideroblasts.

NUP214-ABL1 fusion defines a rare subtype of B-cell precursor acute lymphoblastic leukemia that could benefit from tyrosine kinase inhibitors.

We report a case of myeloproliferative neoplasm (MPN) with an atypical t(9;22;15)(p24;q11;q21) translocation, leading to a BCR-JAK2 fusion, associated with a trisomy of chromosome 8 in clonal evolution at karyotype. Patient's evolution was marked by an aggressive clinical course with rapid progression to blast phase within the first year after diagnosis. Examination of matched chronic phase and blast crisis samples by SNP-array karyotyping identified secondary acquired cryptic genetic events at the time of lymphoblastic transformation, including biallelic IKZF1 alteration and EBF1 and CDKN2A/B codeletions. This case is the first report describing acquisition of secondary genetic events leading to acute lymphoblastic progression in a rare MPN with BCR-JAK2 fusion.

Acquisition of genomic events leading to lymphoblastic transformation in a rare case of myeloproliferative neoplasm with BCR-JAK2 fusion transcript.

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.

Comprehensive mutational profiling of core binding factor acute myeloid leukemia.

Bromodomain and extraterminal (BET) proteins are chromatin readers that preferentially affect the transcription of genes with super-enhancers, including oncogenes. BET proteins bind acetylated histone tails via their bromodomain, bringing the elongation complex to the promoter region. OTX015 (MK-8628) specifically binds to BRD2, BRD3, and BRD4, preventing BET proteins from binding to the chromatin, thus inhibiting gene transcription. OTX015 inhibits proliferation in many haematological malignancy cell lines and patient cells, in vitro and in vivo. We aimed to establish the recommended dose of OTX015 in patients with haematological malignancies. We report the results of patients with acute leukaemia (leukaemia cohort).

Bromodomain inhibitor OTX015 in patients with acute leukaemia: a dose-escalation, phase 1 study.

CD81 is a cell surface protein which belongs to the tetraspanin family. While in multiple myeloma its expression on plasma cells is associated with worse prognosis, this has not yet been explored in acute myeloid leukemia (AML). We measured membrane expression of CD81 on AML cells at diagnosis, evaluated its association with AML characteristics and its influence on patient outcome after intensive chemotherapy in a cohort of 134 patients. CD81 was detected in 92/134 (69%) patients. Patients with AML expressing CD81 had elevated leukocyte count (P=0.02) and were more likely classified as intermediate or adverse-risk by cytogenetics (P<0.001). CD81 expression had a negative impact on survival (event-free survival, overall survival and relapse-free survival) in univariate (P<0.001) and in multivariate analyses (P=0.003, 0.002 and <0.001, respectively). CD81 has a negative impact on OS in patients with NPM1 mutation (P=0.01) and in patients ELN-favorable (P=0.002). In conclusion, this cell surface marker may be a new prognostic marker for diagnostic risk classification and a potential therapeutic target for drug development in AML.

Tetraspanin CD81 is an adverse prognostic marker in acute myeloid leukemia.

The determination of an underlying genetic predisposition is not automatically part of the diagnosis of hematological malignancies (HM) in routine practice. However, it is assumed that genetic predispositions to HM are currently underestimated due to great variations in disease phenotype, variable latency and incomplete penetrance. Most of patients do not display any biological or clinical signs besides the overt hematological disease and many of them have a lack of personal or family history of malignancies. Areas covered: Collaborative studies and important advances in molecular testing have led to the discovery of several genes recurrently deregulated in familial HM including RUNX1, CEBPA, GATA2, ANKRD26, SRP72, PAX5, DDX41, ETV6, ATG2B/GSKIP and TERT/TERC. This review summarizes biological and clinical findings encountered within these disorders. Expert commentary: Identify and manage individuals with genetic predisposition is a current challenge for hematologists. Their identification has immediate implications for hematopoietic stem cell transplantation including donor selection and conditioning regimen. Importantly, several features, including familial and personal history as well as molecular and cytogenetic findings, may help clinicians to suspect an underlying genetic predisposition.

Myelodysplastic syndromes and acute leukemia with genetic predispositions: a new challenge for hematologists.

Minimal residual disease (MRD) is known to be an independent prognostic factor in patients with acute lymphoblastic leukemia (ALL). High-throughput sequencing (HTS) is currently used in routine practice for the diagnosis and follow-up of patients with hematological neoplasms. In this retrospective study, we examined the role of immunoglobulin/T-cell receptor-based MRD in patients with ALL by HTS analysis of immunoglobulin H and/or T-cell receptor gamma chain loci in bone marrow samples from 11 patients with ALL, at diagnosis and during follow-up. We assessed the clinical feasibility of using combined HTS and bioinformatics analysis with interactive visualization using Vidjil software. We discuss the advantages and drawbacks of HTS for monitoring MRD. HTS gives a more complete insight of the leukemic population than conventional real-time quantitative PCR (qPCR), and allows identification of new emerging clones at each time point of the monitoring. Thus, HTS monitoring of Ig/TR based MRD is expected to improve the management of patients with ALL.

High-throughput sequencing in acute lymphoblastic leukemia: Follow-up of minimal residual disease and emergence of new clones.

ETV6 is a target of recurrent aberrations in sporadic and familial acute lymphoblastic leukemia (ALL). Here, we report on a new pedigree with a germline ETV6 mutation in which the index patient and his father developed high hyperdiploid (HeH) ALL and polycythemia vera at age 13 and 51, respectively. The index patient achieved durable complete remission without transplantation but had persistent moderate thrombocytopenia without bleeding tendency. To determine the prevalence of ETV6 alterations in HeH-ALL, we screened 81 unrelated subjects with HeH-ALL by single nucleotide polymorphism array and high-throughput sequencing for the ETV6 gene. Overall, ETV6 microdeletions and mutations were identified in 9% of cases, all of which were somatic and considered as secondary events. Apart from the index patient, no germline ETV6 aberration was identified. Finally, we reviewed the literature for ETV6 germline aberrations and predispositions to ALL.

Detection of a new heterozygous germline ETV6 mutation in a case with hyperdiploid acute lymphoblastic leukemia.

Acute myeloid leukemia (AML) with t(8;21) and inv(16), together referred as core binding factor (CBF)-AML, are recognized as unique entities. Both rearrangements share a common pathophysiology, the disruption of the CBF, and a relatively good prognosis. Experiments have demonstrated that CBF rearrangements were insufficient to induce leukemia, implying the existence of cooperating events. To explore these aberrations, we performed single nucleotide polymorphism (SNP)-array in a well-annotated cohort of 198 patients with CBF-AML. Excluding breakpoint-associated lesions, the most frequent events included loss of a sex chromosome (53%), deletions at 9q21 (12%) and 7q36 (9%) in patients with t(8;21) compared with trisomy 22 (13%), trisomy 8 (10%) and 7q36 deletions (12%) in patients with inv(16). SNP-array revealed novel recurrent genetic alterations likely to be involved in CBF-AML leukemogenesis.mutations (20% of t(8;21)-AML) were shown to be a target of copy-neutral losses of heterozygosity (CN-LOH) at chromosome 19p.focal deletions were identified in 5% of inv(16)-AML while sequence analysis revealed that 2% carriedtruncating mutations. Finally,disruption was found in both subtypes (4.5% of the whole cohort) and possibly highlighted a new lesion associated with aberrant tyrosine kinase signaling in this particular subtype of leukemia.

ArticleTotal : 2	Year
Publication title Cited by 15	2018
Publication title	2026

Article	Year
Unlike AML1, CBFbeta gene is not deregulated by point mutations in acute myeloid leukemia and in myelodysplastic syndromes. Blood\| PubMed ID: 11986246	2002
M0 AML, clinical and biologic features of the disease, including AML1 gene mutations: a report of 59 cases by the Groupe Français d'Hématologie Cellulaire (GFHC) and the Groupe Français de C... Blood\| PubMed ID: 12393381	2003
Mesenchymal cells generated from patients with myelodysplastic syndromes are devoid of chromosomal clonal markers and support short- and long-term hematopoiesis in vitro. Oncogene\| PubMed ID: 15735749	2005
Involvement of a common progenitor cell in core binding factor acute myeloid leukaemia associated with mastocytosis. Leukemia research\| PubMed ID: 22871474	2012
Linezolid induces ring sideroblasts. Haematologica\| PubMed ID: 24186315	2013
NUP214-ABL1 fusion defines a rare subtype of B-cell precursor acute lymphoblastic leukemia that could benefit from tyrosine kinase inhibitors. Haematologica\| PubMed ID: 26681761	2016
Acquisition of genomic events leading to lymphoblastic transformation in a rare case of myeloproliferative neoplasm with BCR-JAK2 fusion transcript. European journal of haematology\| PubMed ID: 26935241	2016
Comprehensive mutational profiling of core binding factor acute myeloid leukemia. Blood\| PubMed ID: 26980726	2016
Bromodomain inhibitor OTX015 in patients with acute leukaemia: a dose-escalation, phase 1 study. The Lancet. Haematology\| PubMed ID: 27063977	2016
Tetraspanin CD81 is an adverse prognostic marker in acute myeloid leukemia. Oncotarget\| PubMed ID: 27566555	2016
Myelodysplastic syndromes and acute leukemia with genetic predispositions: a new challenge for hematologists. Expert review of hematology\| PubMed ID: 27819178	2016
High-throughput sequencing in acute lymphoblastic leukemia: Follow-up of minimal residual disease and emergence of new clones. Leukemia research\| PubMed ID: 27930944	2017
Detection of a new heterozygous germline ETV6 mutation in a case with hyperdiploid acute lymphoblastic leukemia. European journal of haematology\| PubMed ID: 29034503	2018
SNP-array lesions in core binding factor acute myeloid leukemia. Oncotarget\| PubMed ID: 29464086	2018

Claude Preudhomme

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