showing 28 related works from this author
Targeting components of the alternative NHEJ pathway sensitizes KRAS mutant leukemic cells to chemotherapy.
2014
Abstract Activating KRAS mutations are detected in a substantial number of hematologic malignancies. In a murine T-cell acute lymphoblastic leukemia (T-ALL) model, we previously showed that expression of oncogenic Kras induced a premalignant state accompanied with an arrest in T-cell differentiation and acquisition of somatic Notch1 mutations. These findings prompted us to investigate whether the expression of oncogenic KRAS directly affects DNA damage repair. Applying divergent, but complementary, genetic approaches, we demonstrate that the expression of KRAS mutants is associated with increased expression of DNA ligase 3α, poly(ADP-ribose) polymerase 1 (PARP1), and X-ray repair cross-comp…
Monitoring of FLT3 Phosphorylation and FLT3 Ligand Levels in Patients with FLT3-ITD Mutated Acute Myeloid Leukemia (AML) Treated with Midostaurin wit…
2018
Abstract Background: Target inhibition of FLT3 by therapy with the recently FDA- and EMA-approved multi-targeted tyrosine kinase inhibitor (TKI) midostaurin can be monitored by plasma inhibitor activity (PIA) analysis by visualizing the level of target-dephosphorylation as previously described. When combining intensive chemotherapy with midostaurin, we have recently shown that the TKI achieves the lowest level of FLT3 phosphorylation (p-FLT3) at the end of the 1st induction cycle, indicating a deep target inhibition. However, sufficient inhibition could not be maintained during subsequent cycles by midostaurin in combination with chemotherapy, but it was reestablished during maintenance the…
Monitoring of Minimal Residual Disease (MRD) of DNMT3A Mutations (DNMT3Amut) in Acute Myeloid Leukemia (AML): A Study of the AML Study Group (AMLSG)
2015
![Graphic][1] Background : The DNA methyltransferase 3A ( DNMT3A) is one of the most frequent mutated genes in AML with a hot spot mutation at codon R882 in 80% of the DNMT3A mut cases. In most of the studies DNMT3A mut predicts for poor overall (OS) and relapse-free survival (RFS). Recently, DNMT3A mut have been associated with age-related clonal hematopoiesis, and they have been identified in early preleukemic stem cells. These findings suggest that DNMT3A mut represents an early event in leukemogenesis and may be part of the leukemia founder clone in most AMLs harboring a DNMT3A mut. We thought to address the question whether MRD monitoring in DNMT3A mut patients (pts) can be used for pr…
MLL-Rearranged Leukemia Is Dependent on Aberrant H3K79 Methylation by DOT1L
2011
SummaryThe histone 3 lysine 79 (H3K79) methyltransferase Dot1l has been implicated in the development of leukemias bearing translocations of the Mixed Lineage Leukemia (MLL) gene. We identified the MLL-fusion targets in an MLL-AF9 leukemia model, and conducted epigenetic profiling for H3K79me2, H3K4me3, H3K27me3, and H3K36me3 in hematopoietic progenitor and leukemia stem cells (LSCs). We found abnormal profiles only for H3K79me2 on MLL-AF9 fusion target loci in LSCs. Inactivation of Dot1l led to downregulation of direct MLL-AF9 targets and an MLL translocation-associated gene expression signature, whereas global gene expression remained largely unaffected. Suppression of MLL translocation-a…
Measurable Residual Disease (MRD) Monitoring in Acute Myeloid Leukemia (AML) with t(8;21)(q22;q22.1) RUNX1-RUNX1T1 Identifies Patients at High Risk o…
2019
Background: Acute myeloid leukemia (AML) with t(8;21)(q22;q22.1) resulting in the RUNX1-RUNX1T1 gene fusion is considered favorable in the 2017 genetic risk stratification by the European LeukemiaNet (ELN). After intensive chemotherapy most patients (pts) achieve complete remission (CR), but relapse occurs in about 50% and is associated with poor prognosis. In this AML subgroup monitoring of measurable residual disease (MRD) has been shown to identify pts at higher risk of relapse. Aims: To assess the prognostic impact of MRD monitoring in bone marrow (BM) and peripheral blood (PB) in a large cohort of 155 clinically well-annotated t(8;21)-AML pts enrolled in one of six AMLSG treatment tria…
Expression Of FLT3-ITD Dysregulates The DBC1-Sirt1-p53 Signaling and Promotes Therapy Resistance
2013
Abstract Background SIRT1 is a NAD+ dependent histone deacetylase, which has been shown to act as an important regulator of apoptosis, DNA-repair and is involved in the maintenance of genetic integrity under conditions of cellular stress. Beside deacetylation of histones H4K16, SIRT1 has numeral other substrates including KU70, FOXO1 or p53. SIRT1 deacetylates p53 at lysine 382 thereby reducing its transcriptional activity followed by loss of p53 dependent apoptosis in response to cell damage. The activity of SIRT1 is negatively regulated by DBC1 (Deleted in Breast Cancer 1) and involves protein–protein interaction (Kim et al., Nature 2008). Recent reports have demonstrated increased expres…
SIRT1 prevents genotoxic stress-induced p53 activation in acute myeloid leukemia
2014
SIRT1 is an important regulator of cellular stress response and genomic integrity. Its role in tumorigenesis is controversial. Whereas sirtuin 1 (SIRT1) can act as a tumor suppressor in some solid tumors, increased expression has been demonstrated in many cancers, including hematologic malignancies. In chronic myeloid leukemia, SIRT1 promoted leukemia development, and targeting SIRT1 sensitized chronic myeloid leukemia progenitors to tyrosine kinase inhibitor treatment. In this study, we investigated the role of SIRT1 in acute myeloid leukemia (AML). We show that SIRT1 protein, but not RNA levels, is overexpressed in AML samples harboring activating mutations in signaling pathways. In FMS-l…
Assessment of Clonal Evolution in 42 AML with NPM1 Mutations by Molecular Characterization of Paired Diagnosis and Relapse Samples
2011
Abstract Abstract 237 Mutations in the nucleophosmin 1 (NPM1) gene represent one of the most frequent gene mutations in acute myeloid leukemia (AML), in particular in cytogenetically normal (CN)-AML. NPM1 mutations (NPM1mut) are considered as an early genetic event in the pathogenesis of AML. To address the role of clonal evolution from diagnosis to relapse in NPM1mut AML, we applied high-resolution genome-wide single nucleotide polymorphism (SNP) array analysis using the Affymetrix 6.0 platform to detect copy number alterations (CNAs) and uniparental disomies (UPDs) in paired samples from 42 patients. In addition, we determined NPM1 and FLT3 [internal tandem duplication (ITD) and tyrosine …
Minimal Residual Disease Monitoring in Acute Myeloid Leukemia (AML) with Translocation t(8;21)(q22;q22): Results of the AML Study Group (AMLSG)
2016
Abstract Background: Acute myeloid leukemia (AML) with t(8;21)(q22;q22) results in the formation of the RUNX1-RUNX1T1 fusion transcript which can be used to monitor minimal residual disease (MRD) by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Early identification of patients (pts) with a high risk of relapse will allow pre-emptive therapy including allogeneic hematopoietic cell transplantation (alloHCT). Recent studies in AML with NPM1 mutation or the CBFB-MYH11 gene fusion revealed that MRD persistence is significantly associated with a high risk of relapse. However, the prognostic impact of MRD assessment in RUNX1-RUNX1T1-positive AML is not well established. A…
Differential impact of allelic ratio and insertion site in FLT3-ITD-positive AML with respect to allogeneic transplantation.
2014
The objective was to evaluate the prognostic and predictive impact of allelic ratio and insertion site (IS) of internal tandem duplications (ITDs), as well as concurrent gene mutations, with regard to postremission therapy in 323 patients with FLT3-ITD-positive acute myeloid leukemia (AML). Increasing FLT3-ITD allelic ratio (P = .004) and IS in the tyrosine kinase domain 1 (TKD1, P = .06) were associated with low complete remission (CR) rates. After postremission therapy including intensive chemotherapy (n = 121) or autologous hematopoietic stem cell transplantation (HSCT, n = 17), an allelic ratio ≥ 0.51 was associated with an unfavorable relapse-free (RFS, P = .0008) and overall survival …
Clonal evolution in relapsed NPM1-mutated acute myeloid leukemia.
2013
Mutations in the nucleophosmin 1 (NPM1) gene are considered a founder event in the pathogenesis of acute myeloid leukemia (AML). To address the role of clonal evolution in relapsed NPM1-mutated (NPM1mut) AML, we applied high-resolution, genome-wide, single-nucleotide polymorphism array profiling to detect copy number alterations (CNAs) and uniparental disomies (UPDs) and performed comprehensive gene mutation screening in 53 paired bone marrow/peripheral blood samples obtained at diagnosis and relapse. At diagnosis, 15 aberrations (CNAs, n = 10; UPDs, n = 5) were identified in 13 patients (25%), whereas at relapse, 56 genomic alterations (CNAs, n = 46; UPDs, n = 10) were detected in 29 patie…
Identifying Prognostic SNPs in Clinical Cohorts: Complementing Univariate Analyses by Resampling and Multivariable Modeling
2016
Clinical cohorts with time-to-event endpoints are increasingly characterized by measurements of a number of single nucleotide polymorphisms that is by a magnitude larger than the number of measurements typically considered at the gene level. At the same time, the size of clinical cohorts often is still limited, calling for novel analysis strategies for identifying potentially prognostic SNPs that can help to better characterize disease processes. We propose such a strategy, drawing on univariate testing ideas from epidemiological case-controls studies on the one hand, and multivariable regression techniques as developed for gene expression data on the other hand. In particular, we focus on …
Polatuzumab vedotin as a salvage and bridging treatment in relapsed or refractory large B-cell lymphomas
2021
The antibody-drug conjugate polatuzumab vedotin (pola) has recently been approved in combination with bendamustine and rituximab (pola-BR) for patients with refractory or relapsed (r/r) large B-cell lymphoma (LBCL). To investigate the efficacy of pola-BR in a real-world setting, we retrospectively analyzed 105 patients with LBCL who were treated in 26 German centers under the national compassionate use program. Fifty-four patients received pola as a salvage treatment and 51 patients were treated with pola with the intention to bridge to chimeric antigen receptor (CAR) T-cell therapy (n = 41) or allogeneic hematopoietic cell transplantation (n = 10). Notably, patients in the salvage and brid…
Role of Donor Clonal Hematopoiesis in Allogeneic Hematopoietic Stem-Cell Transplantation
2018
Purpose Clonal hematopoiesis of indeterminate potential (CHIP) occurs in the blood of approximately 20% of older persons. CHIP is linked to an increased risk of hematologic malignancies and of all-cause mortality; thus, the eligibility of stem-cell donors with CHIP is questionable. We comprehensively investigated how donor CHIP affects outcome of allogeneic hematopoietic stem-cell transplantation (HSCT). Methods We collected blood samples from 500 healthy, related HSCT donors (age ≥ 55 years) at the time of stem-cell donation for targeted sequencing with a 66-gene panel. The effect of donor CHIP was assessed on recipient outcomes, including graft-versus-host disease (GVHD), cumulative incid…
Next-Generation Sequencing (NGS)-Based Measurable Residual Disease (MRD) Monitoring in Acute Myeloid Leukemia with FLT3 Internal Tandem Duplication (…
2020
Background: FLT3-ITD occurs in ~25% of adult AML patients (pts) and is associated with poor prognosis. MRD monitoring is of high prognostic relevance, but restricted to certain AML subtypes. FLT3-ITD represents an attractive target for MRD monitoring in particular in pts treated with a tyrosine kinase inhibitor. FLT3-ITD MRD monitoring is hampered by the broad heterogeneity of ITD length and insertion site (IS). NGS may overcome these limitations offering the opportunity for MRD monitoring in FLT3-ITD+ AML. Aims: To validate our recently established NGS-based FLT3-ITD MRD assay in a defined cohort of FLT3-ITD+ AML pts treated within the AMLSG16-10 trial (NCT01477606) combining intensive che…
DNMT3A mutations Predict for Inferior Outcome in NPM1-Wildtype and Molecular Unfavorable Cytogenetically-Normal Acute Myeloid Leukemia: A Study of th…
2011
Abstract Abstract 415 Background: Alteration of DNA methylation, a hallmark of epigenetic modification, is currently discussed as one important pathomechanism in leukemogenesis. Using a next-generation sequencing approach, a frameshift mutation of the gene encoding the DNA methyltransferase (DNMT3A) in an acute myeloid leukemia (AML) case was identified. DNMT3A catalyses the addition of a methyl group to the cytosine residue of CpG dinucleotides, thereby affecting promoter methylation status and gene expression. Subsequent sequencing analysis in an independent cohort of 288 AML patients (pts) revealed DNMT3A mutations (DNMT3Amut) in 22% of the pts; mutations were associated with intermediat…
Targeting Aberrant Ncam (neural cell adhesion molecule; CD56) Expression in Acute Myeloid Leukemia
2015
Abstract Background Acute myeloid leukemia (AML) is a heterogeneous disease of the hematopoietic progenitor cell driven by the subsequent acquisition of genetic alterations. Approximately 20% of AML patients show strong expression of CD56 (neural cell adhesion molecule; NCAM). Expression of NCAM is associated with poor overall survival; however, the functional role of aberrant NCAM expression has not been investigated to date. The goal of this study is to examine the biological role of NCAM in AML and to explore whether NCAM represents a potential therapeutic target. Results In order to evaluate the clinical significance of elevated NCAM expression in AML, we screened a panel of human cell …
Partitioned learning of deep Boltzmann machines for SNP data.
2016
Abstract Motivation Learning the joint distributions of measurements, and in particular identification of an appropriate low-dimensional manifold, has been found to be a powerful ingredient of deep leaning approaches. Yet, such approaches have hardly been applied to single nucleotide polymorphism (SNP) data, probably due to the high number of features typically exceeding the number of studied individuals. Results After a brief overview of how deep Boltzmann machines (DBMs), a deep learning approach, can be adapted to SNP data in principle, we specifically present a way to alleviate the dimensionality problem by partitioned learning. We propose a sparse regression approach to coarsely screen…
Midostaurin Plus Intensive Chemotherapy for Younger and Older Patients with Acute Myeloid Leukemia and FLT3 Internal Tandem Duplications
2021
Abstract BACKGROUND: Midostaurin is a first-generation, type I multi-targeted kinase inhibitor with inhibitory activity against FLT3-ITD and -TKD mutations. Midostaurin is approved by FDA and EMA in combination with intensive induction and consolidation chemotherapy for adult patients with AML exhibiting an activating FLT3 mutation; the EMA label also includes single-agent maintenance therapy following consolidation chemotherapy. We conducted a phase-II trial (AMLSG 16-10) to evaluate midostaurin with induction chemotherapy followed by allogeneic hematopoietic-cell transplantation (HCT) and a one-year midostaurin maintenance therapy in younger and older patients with acute myeloid leukemia …
Clinical Impact of GATA2 Mutations in Acute Myeloid Leukemia Patients Harboring CEBPA Mutations: A Study of the AML Study Group (AMLSG)
2013
Abstract Background Based on their association with certain biological and clinical features as well as their prognostic significance, mutations in the CCAAT/enhancer-binding protein-alpha (CEBPA) gene have been included as a provisional entity into the 2008 World Health Organization (WHO) classification of myeloid neoplasms. CEBPA mutations (CEBPAmut) are mainly found in acute myeloid leukemia (AML) with normal cytogenetics, and approximately 60% of the mutated patients (pts) carry biallelic mutations. Several studies showed that in particular pts with double mutant CEBPA (CEBPAdm) have a favorable outcome compared to all others. Recently, mutations in the transcription factor GATA2 were i…
Polatuzumab Vedotin in Relapsed and Refractory (r/r) Large B-Cell Lymphoma (LBCL): Real-World Data of the German National Compassionate Use Program (…
2020
Introduction The antibody-drug conjugate polatuzumab vedotin (Pola) has recently been approved in combination with bendamustine and rituximab (Pola-BR) for patients with r/r diffuse LBCL (DLBCL). Methods To characterize the efficacy of Pola-BR in a real-world setting, we retrospectively analyzed data from 97 patients with r/r LBCL who were treated with Pola in 24 German centers within the national CUP. Clinical baseline and follow-up (FU) data were collected by chart review and summarized descriptively. Progression-free survival (PFS) and overall survival (OS) were analyzed using Kaplan-Meier and Cox regression methods. Fisher's exact test was used to compare categorical factors between gro…
Therapy for Recurrent High-Grade Gliomas: Results of a Prospective Multicenter Study on Health-Related Quality of Life
2017
Objective To assess the impact of therapy on patients' health-related quality of life (HRQoL) in recurrent high-grade glioma (HGG) in an unselected cohort. Methods In this prospective multicenter study, we analyzed European Organization for Research and Treatment of Cancer Quality of Life core questionnaire and European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Brain Neoplasm module questionnaires of 92 patients within 1 year after diagnosis of tumor recurrence of a HGG and respective treatment. We evaluated the influence of re-radiation, second- and third-line chemotherapies, and number of recurrent surgeries on summary scores for functioning, symptoms…
Molecular Characterization of Relapsed Core-Binding Factor (CBF) Acute Myeloid Leukemia (AML)
2015
Abstract Background: CBF-AML is defined by recurrent genetic abnormalities which encompass t(8;21)(q22;q22), inv(16)(p13.1q22) or less frequently t(16;16)(p13.1;q22). Most frequent secondary chromosome aberrations in t(8;21) AML are del(9q) or loss of a sex chromosome, and in inv(16)/t(16;16) AML trisomy 22 or trisomy 8. At the molecular level mutations involving KIT, FLT3, or NRAS were identified as recurrent lesions in CBF-AML. However, the underlying genetic alterations which might trigger relapse in CBF-AML are not well delineated. Thus, the aim of our study was to characterize the clonal architecture of relapsed CBF-AML. Methods: We performed mutational profiling (KIT, FLT3-ITD, FLT3-T…
Tailoring sparse multivariable regression techniques for prognostic single-nucleotide polymorphism signatures.
2011
When seeking prognostic information for patients, modern technologies provide a huge amount of genomic measurements as a starting point. For single-nucleotide polymorphisms (SNPs), there may be more than one million covariates that need to be simultaneously considered with respect to a clinical endpoint. Although the underlying biological problem cannot be solved on the basis of clinical cohorts of only modest size, some important SNPs might still be identified. Sparse multivariable regression techniques have recently become available for automatically identifying prognostic molecular signatures that comprise relatively few covariates and provide reasonable prediction performance. For illus…
Pharmacodynamic Monitoring of the Efficacy of a Targeted Therapy with Midostaurin By Plasma Inhibitor Activity (PIA) Analysis in FLT3 -ITD Positive A…
2015
Abstract Background: Activating mutations in receptor tyrosine kinases like FLT3 (FLT3mut) lead to an aberrant signal transduction thereby causing an increased proliferation of hematopoietic cells. Internal tandem duplications (FLT3-ITD) or mutations in the tyrosine kinase domain (FLT3-TKD) occur in about 25% of younger adult patients (pts) with acute myeloid leukemia (AML), with FLT3 -ITD being associated with an unfavourable outcome. FLT3mut present an excellent target for small molecule tyrosine kinase inhibitors (TKI). The multi-targeted kinase inhibitor midostaurin (PKC412) is currently under investigation as a FLT3-inhibitor in combination with intensive chemotherapy. Monitoring of th…
ACTR-58. PHASE III TRIAL OF CCNU/TEMOZOLOMIDE (TMZ) COMBINATION THERAPY VS. STANDARD TMZ THERAPY FOR NEWLY DIAGNOSED MGMT-METHYLATED GLIOBLASTOMA PAT…
2017
There is an urgent need for more effective therapies in glioblastoma (GBM). Data from the single arm UKT-03 trial (Glas et al., J Clin Oncol 27, 1257, 2009) suggested that combined lomustine/temozolomide (CCNU/TMZ) therapy might have superior activity in MGMT-methylated GBM. The phase III CeTeG/NOA-09 trial was set up to test this hypothesis in a randomized setting. Patients with MGMT-methylated GBM were randomized (1:1) for standard therapy with daily TMZ (75 mg/m2) during local radiotherapy (RT, 30 x 2 Gy) followed by 6 courses of TMZ (150–200 mg/m2/day for 5 days q4w) or experimental therapy with CCNU/TMZ in addition to local RT. Six 6-week courses of CCNU/TMZ (CCNU 100 mg/m2 d1, TMZ 100…
Clinical impact of GATA2 mutations in acute myeloid leukemia patients harboring CEBPA mutations: a study of the AML study group.
2016
Clinical impact of GATA2 mutations in acute myeloid leukemia patients harboring CEBPA mutations: a study of the AML study group
Lomustine-temozolomide combination therapy versus standard temozolomide therapy in patients with newly diagnosed glioblastoma with methylated MGMT pr…
2019
Summary Background There is an urgent need for more effective therapies for glioblastoma. Data from a previous unrandomised phase 2 trial suggested that lomustine-temozolomide plus radiotherapy might be superior to temozolomide chemoradiotherapy in newly diagnosed glioblastoma with methylation of the MGMT promoter. In the CeTeG/NOA-09 trial, we aimed to further investigate the effect of lomustine-temozolomide therapy in the setting of a randomised phase 3 trial. Methods In this open-label, randomised, phase 3 trial, we enrolled patients from 17 German university hospitals who were aged 18–70 years, with newly diagnosed glioblastoma with methylated MGMT promoter, and a Karnofsky Performance …