Publications by authors named "Susanne Schnittger"

241 Publications

A phase I study of a dual PI3-kinase/mTOR inhibitor BEZ235 in adult patients with relapsed or refractory acute leukemia.

BMC Pharmacol Toxicol 2020 09 29;21(1):70. Epub 2020 Sep 29.

School of Medicine, Cardiff University, Cardiff, Wales, UK.

Background: Combined inhibition of phosphatidylinositol 3-kinase (PI3K) and the mammalian target of rapamycin (mTOR) complexes may be an efficient treatment for acute leukemia. The primary objective of this phase I single center open label study was to determine the maximum tolerated dose (MTD) and recommended phase II dose (RP2D) of the dual pan-class I PI3K and mTOR inhibitor BEZ235 in patients with advanced leukemia.

Methods: Herein patients > 18 years of age who had relapsed or showed refractory leukemia were treated with BEZ235 (orally at 300-400 mg BID (cohort - 1/1)) to assess safety, tolerability, preliminary efficacy and pharmacokinetic (PK). Adverse events data and serious adverse events were analyzed and haematological and clinical biochemistry toxicities were assessed from laboratory test parameters. Response was assessed for the first time at the end of cycle 1 (day 29) and after every subsequent cycle. Pharmacokinetic and pharmacodynamic analyses of BEZ235 were also included (BEZ235 plasma levels, phosphorylation of AKT, S6 and 4EBP1). On statistics this trial is a multiple ascending dose study in which a following variant of the 3 + 3 rule ("Rolling Six"), a minimum of 6 and a maximum of 12 patients was recruited for the dose escalation and another 5 were planned for the expansion phase.

Results: Twenty-four patients with ALL (n = 11) or AML (n = 12) or CML-BP (n = 1) were enrolled. All patients had failed one (n = 5) or more lines of therapy (n = 5) and 14 patients were in refractory / refractory relapse. No formal MTD was defined, stomatitis and gastrointestinal toxicity at 400 mg BID dose was considered incompatible with prolonged treatment. The RP2D of BEZ235 was defined as 300 mg BID. Four of 24 patients showed clinical benefit. Twenty-two of 24 patients discontinued because of progression, (median time to progression 27 days (4d-112d). There was no association between PK parameters and efficacy or tolerability.

Conclusions: Combined inhibition of PI3K and mTOR inhibits a clinically meaningful driver pathway in a small subset of patients with ALL, with no benefit in patients with AML.

Trial Registration: ClinicalTrials.gov , identifier NCT01756118. retrospectively registered 19th December 2012, https://clinicaltrials.gov/ct2/show/NCT01756118 .
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http://dx.doi.org/10.1186/s40360-020-00446-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7523358PMC
September 2020

Frontline therapy of acute promyelocytic leukemia: Randomized comparison of ATRA and intensified chemotherapy versus ATRA and anthracyclines.

Eur J Haematol 2018 Feb 4;100(2):154-162. Epub 2017 Dec 4.

Internal Medicine III, University Hospital Grosshadern, Ludwig-Maximilian-University Munich, Munich, Germany.

Objectives: Randomized comparison of two treatment strategies in frontline therapy of acute promyelocytic leukemia (APL): all-trans retinoic acid (ATRA) and double induction intensified by high-dose cytosine arabinoside (HD ara-C) (German AMLCG) and therapy with ATRA and anthracyclines (Spanish PETHEMA, LPA99).

Patients And Results: Eighty of 87 adult patients with genetically confirmed APL of all risk groups were eligible. The outcome of both arms was similar: AMLCG vs PETHEMA: hematological complete remission 87% vs 83%, early death 13% vs 17% (P = .76), overall survival, event-free survival, leukemia-free survival, cumulative incidence of relapse at 6 years 75% vs 78% (P = .92); 75% vs 68% (P = .29); 86% vs 81% (P = .28); and 0% vs 12% (P = .04, no relapse vs four relapses), respectively. The median time to achieve molecular remission (RT-PCR negativity of PML-RARA) was 60 days in both arms (P = .12). The AMLCG regimen was associated with a longer duration of neutropenia (P = .02) and a higher rate of WHO grade ≥3 infections.

Conclusions: The small number of patients limits the reliability of conclusions. With these restrictions, the outcomes of both approaches were similar and show the limitations of ATRA and chemotherapy. The HD ara-C-containing regimen was associated with a lower relapse rate in high-risk APL.
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http://dx.doi.org/10.1111/ejh.12994DOI Listing
February 2018

Dasatinib and Azacitidine Followed by Haploidentical Stem Cell Transplant for Chronic Myeloid Leukemia with Evolving Myelodysplasia: A Case Report and Review of Treatment Options.

Am J Case Rep 2017 Oct 16;18:1099-1109. Epub 2017 Oct 16.

Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff, Wales, United Kingdom.

BACKGROUND CML presenting with a variant Philadelphia translocation, atypical BCR-ABL transcript, additional chromosomal aberrations, and evolving MDS is uncommon and therapeutically challenging. The prognostic significance of these genetic findings is uncertain, even as singular aberrations, with nearly no data on management and outcome when they coexist. MDS evolving during the course of CML may be either treatment-associated or an independently coexisting disease, and is generally considered to have an inferior prognosis. Tyrosine kinase inhibitors (TKI) directed against BCR-ABL are the mainstay of treatment for CML, whereas treatment modalities that may be utilized for MDS and CML include allogeneic stem cell transplant and - at least conceptually - hypomethylating agents. CASE REPORT Here, we describe the clinical course of such a patient, demonstrating that long-term combined treatment with dasatinib and azacitidine for coexisting CML and MDS is feasible and well tolerated, and may be capable of slowing disease progression. This combination therapy had no deleterious effect on subsequent potentially curative haploidentical bone marrow transplantation. CONCLUSIONS The different prognostic implications of this unusual case and new therapeutic options in CML are discussed, together with a review of the current literature on CML presenting with different types of genomic aberrations and the coincident development of MDS. Additionally, this case gives an example of long-term combined treatment of tyrosine kinase inhibitors and hypomethylating agents, which could be pioneering in CML treatment.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5652250PMC
http://dx.doi.org/10.12659/ajcr.904956DOI Listing
October 2017

Feasibility of BAALC gene expression for detection of minimal residual disease and risk stratification in normal karyotype acute myeloid leukaemia.

Br J Haematol 2016 Dec 23;175(5):904-916. Epub 2016 Sep 23.

MLL Munich Leukaemia Laboratory, Munich, Germany.

High BAALC gene expression has been associated with poor prognosis in cytogenetically normal acute myeloid leukaemia (CN-AML) and has been suggested as a suitable marker for assessing minimal residual disease (MRD). The purpose of this study was to substantiate these findings by the analysis of a large data set of 632 diagnostic and follow-up samples in 142 intensively treated CN-AML patients. Paired diagnostic/relapse samples of 35 patients revealed stable high BAALC expression in 89%, irrespective of a high proportion of clonal evolution found in 49% of these cases. High BAALC expression, both directly after induction chemotherapy and within 3-6 months after induction chemotherapy, correlated significantly with shorter event-free survival and overall survival. Moreover, 8 of 10 patients displaying high BAALC expression levels after completion of induction therapy as well as 5 of 5 patients exhibiting high BAALC expression levels within 3-6 months after induction chemotherapy experienced relapse with a median of 197 and 101 days, respectively, from sampling to relapse. Thus, BAALC expression-based MRD detection during therapy may be considered a strategy to identify patients at high risk of relapse.
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http://dx.doi.org/10.1111/bjh.14343DOI Listing
December 2016

Gain of chromosome 21 or amplification of chromosome arm 21q is one mechanism for increased ERG expression in acute myeloid leukemia.

Genes Chromosomes Cancer 2016 Feb 6;55(2):148-57. Epub 2015 Nov 6.

MLL Munich Leukemia Laboratory, Munich, Germany.

In acute myeloid leukemia (AML), acquired genomic gains and losses are common and lead to altered expression of genes located within or nearby the affected regions. Increased expression of the ETS-related transcription factor gene ERG has been described in myeloid malignancies with chromosomal rearrangements involving chromosome band 21q22, but also in cytogenetically normal AML, where it is associated with adverse prognosis. In this study, fluorescence in situ hybridization on interphase nuclei disclosed an amplification of the ERG gene (more than six copies) in 33 AML patients with structural rearrangements of 21q22. Array comparative genomic hybridization of these cases disclosed a minimal amplified region at the position 39.6-40.0 Mbp from pter that harbors ERG as the only gene. Analysis by quantitative real-time reverse transcription polymerase chain reaction revealed significantly higher ERG mRNA expression in these patients and in a group of 95 AML patients with complete or partial gain of chromosome 21 (three to six copies) compared with 351 AML patients without gain of chromosome 21. Quantification of ERG DNA copy numbers revealed a strong correlation with ERG mRNA expression. Furthermore, in patients with gain of chromosome 21, higher ERG expression was found to be associated with RUNX1 mutations. Our results suggest that acquired gain of chromosome 21 or amplification of chromosome arm 21q is one mechanism contributing to increased ERG expression in AML.
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http://dx.doi.org/10.1002/gcc.22321DOI Listing
February 2016

Genetic characterization of T-PLL reveals two major biologic subgroups and JAK3 mutations as prognostic marker.

Genes Chromosomes Cancer 2016 Jan 23;55(1):82-94. Epub 2015 Oct 23.

MLL Munich Leukemia Laboratory, Max-Lebsche-Platz 31, Munich, 81377, Germany.

T-cell prolymphocytic leukemia (T-PLL) is a rare post-thymic T-cell neoplasm with aggressive clinical course and short overall survival. So far, due to the rareness of this disease, genetic data are available only from individual cases or small cohorts. In our study, we aimed at performing a comprehensive cytogenetic and molecular genetic characterization of T-PLL comprising the largest cohort of patients with T-PLL analyzed so far, including correlations between the respective markers and their impact on prognosis. Genetic abnormalities were found in all 51 cases with T-PLL, most frequently involving the TCRA/D locus (86%). Deletions were detected for ATM (69%) and TP53 (31%), whereas i(8)(q10) was observed in 61% of cases. Mutations in ATM, TP53, JAK1, and JAK3 were detected in 73, 14, 6, and 21% of patients, respectively. Additionally, BCOR mutations were observed for the first time in a lymphoid malignancy (8%). Two distinct genetic subgroups of T-PLL were identified: A large subset (86% of patients) showed abnormalities involving the TCRA/D locus activating the proto-oncogenes TCL1 or MTCP1, while the second group was characterized by a high frequency of TP53 mutations (4/7 cases). Further, analyses of overall survival identified JAK3 mutations as important prognostic marker, showing a significant negative impact.
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http://dx.doi.org/10.1002/gcc.22313DOI Listing
January 2016

Fusion of PDGFRB to MPRIP, CPSF6, and GOLGB1 in three patients with eosinophilia-associated myeloproliferative neoplasms.

Genes Chromosomes Cancer 2015 Dec 10;54(12):762-70. Epub 2015 Sep 10.

III. Medizinische Klinik, Universitätsmedizin Mannheim, Mannheim, Germany.

In eosinophilia-associated myeloproliferative neoplasms (MPN-eo), constitutive activation of protein tyrosine kinases (TK) as consequence of translocations, inversions, or insertions and creation of TK fusion genes is recurrently observed. The most commonly involved TK and their potential TK inhibitors include PDGFRA at 4q12 or PDGFRB at 5q33 (imatinib), FGFR1 at 8p11 (ponatinib), and JAK2 at 9p24 (ruxolitinib). We here report the identification of three new PDGFRB fusion genes in three male MPN-eo patients: MPRIP-PDGFRB in a case with t(5;17)(q33;p11), CPSF6-PDGFRB in a case with t(5;12)(q33;q15), and GOLGB1-PDGFRB in a case with t(3;5)(q13;q33). The fusion proteins identified by 5'-rapid amplification of cDNA ends polymerase chain reaction (PCR) or DNA-based long distance inverse PCR are predicted to contain the TK domain of PDGFRB. The partner genes contain domains like coiled-coil structures, which are likely to cause dimerization and activation of the TK. In all patients, imatinib induced rapid and durable complete remissions.
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http://dx.doi.org/10.1002/gcc.22287DOI Listing
December 2015

Evaluation of IDH1G105 polymorphism as prognostic marker in intermediate-risk AML.

Ann Hematol 2015 Dec 9;94(12):1991-2001. Epub 2015 Sep 9.

MLL Munich Leukemia Laboratory, Max-Lebsche-Platz 31, 81377, Munich, Germany.

Germline polymorphisms in genes mutated in acute myeloid leukemia (AML) may have prognostic impact. Therefore, the relevance of the polymorphism IDH1G105 (IDH1105(GGT) minor allele) was evaluated in the context of concomitant molecular mutations in a cohort of 507 AML cases with intermediate-risk cytogenetics. In addition, a cohort of 475 healthy controls was analyzed for this polymorphism. IDH1105(GGT) minor allele was found in 10 % of AML patients and 9 % of healthy controls. While no differences were seen with regard to cytomorphology or cytogenetics, immunophenotyping revealed significantly reduced expression of the progenitor marker CD34 in AML cases harboring IDH1105(GGT) minor allele. Cases with IDH1105(GGT) minor allele as compared to those with the IDH1105(GGC) major allele had significantly longer event-free survival (EFS) (median 16 vs 11 months, p = 0.013) which was most pronounced in the age group >60 years (median 14 vs 9 months, p = 0.007) and in the NPM1 mutated/FLT3-ITD/FLT3wt ratio <0.5 group (median 61 vs 13 months, p = 0.012). However, this association is not independent of other prognostic parameters, and we conclude that IDH1105(GGT) minor allele has to be considered in the context of the genetic background of the individual AML analyzed.
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http://dx.doi.org/10.1007/s00277-015-2488-7DOI Listing
December 2015

KIT D816V and JAK2 V617F mutations are seen recurrently in hypereosinophilia of unknown significance.

Am J Hematol 2015 Sep 14;90(9):774-7. Epub 2015 Aug 14.

Department of Hematology and Oncology, University Hospital Mannheim, Mannheim, Germany.

Myeloproliferative neoplasms with eosinophilia are commonly characterized by a normal karyotype and remain poorly defined at the molecular level. We therefore investigated 426 samples from patients with hypereosinophilia of unknown significance initially referred for screening of the FIP1L1-PDGFRA (FP) fusion gene also for KIT D816V and JAK2 V617F mutations. Overall, 86 (20%) patients tested positive: FP+ in 55 (12%), KIT D816V+ in 14 (3%), and JAK2 V617F+ in 17 (4%) patients, respectively. To gain better insight into clinical characteristics, we compared these cases with 31 additional and well-characterized KIT D816V+ eosinophilia-associated systemic mastocytosis (SM-eo) patients enrolled within the "German Registry on Disorders of Eosinophils and Mast cells." Significant differences included younger age, male predominance, and higher eosinophil counts for FP+ cases while abdominal lymphadenopathy, ascites, and serum tryptase levels >100 μg/l were characteristic for those with KIT D816V. Leukocytes, hemoglobin, and splenomegaly did not differ significantly. A median of three additional mutations, most frequently TET2 and SRSF2, were identified in 12/13 KIT D816V+ SM-eo patients with available material indicating a more complex molecular pathogenesis. Median survival was not reached for FP+ cases but was only 26 and 41 months for KIT D816V+ SM and JAK2 V617F+ MPN-eo, respectively. Eosinophilia of ≥2 × 10(9) /l was identified as discriminator for inferior survival in KIT D816V+ and/or JAK2 V617F+ patients (median survival 20 months vs. not reached, P = 0.002). Thus, there is a clear prognostic and therapeutic rationale for detection of KIT D816V and JAK2 V617F in the diagnostic work up of eosinophilia.
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http://dx.doi.org/10.1002/ajh.24075DOI Listing
September 2015

BRCC3 mutations in myeloid neoplasms.

Haematologica 2015 Aug 22;100(8):1051-7. Epub 2015 May 22.

Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA Department of Pathology and Tumor Biology, Kyoto University, Japan

Next generation sequencing technologies have provided insights into the molecular heterogeneity of various myeloid neoplasms, revealing previously unknown somatic genetic events. In our cohort of 1444 cases analyzed by next generation sequencing, somatic mutations in the gene BRCA1-BRCA2-containing complex 3 (BRCC3) were identified in 28 cases (1.9%). BRCC3 is a member of the JAMM/MPN+ family of zinc metalloproteases capable of cleaving Lys-63 linked polyubiquitin chains, and is implicated in DNA repair. The mutations were located throughout its coding region. The average variant allelic frequency of BRCC3 mutations was 30.1%, and by a serial sample analysis at two different time points a BRCC3 mutation was already identified in the initial stage of a myelodysplastic syndrome. BRCC3 mutations commonly occurred in nonsense (n=12), frameshift (n=4), and splice site (n=5) configurations. Due to the marginal male dominance (odds ratio; 2.00, 0.84-4.73) of BRCC3 mutations, the majority of mutations (n=23; 82%) were hemizygous. Phenotypically, BRCC3 mutations were frequently observed in myelodysplastic syndromes and myelodysplastic/myeloproliferative neoplasms and associated with -Y abnormality (odds ratio; 3.70, 1.25-11.0). Clinically, BRCC3 mutations were also related to higher age (P=0.01), although prognosis was not affected. Knockdown of Brcc3 gene expression in murine bone marrow lineage negative, Sca1 positive, c-kit positive cells resulted in 2-fold more colony formation and modest differentiation defect. Thus, BRCC3 likely plays a role as tumor-associated gene in myelodysplastic syndromes and myelodysplastic/myeloproliferative neoplasms.
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http://dx.doi.org/10.3324/haematol.2014.111989DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5004421PMC
August 2015

Molecular diagnostics of myeloproliferative neoplasms.

Eur J Haematol 2015 Oct 18;95(4):270-9. Epub 2015 May 18.

Laboratoire d'Hématologie, Centre Hospitalier Universitaire de Nantes, Nantes, France.

Since the discovery of the JAK2 V617F mutation in the majority of the myeloproliferative neoplasms (MPN) of polycythemia vera, essential thrombocythemia and primary myelofibrosis ten years ago, further MPN-specific mutational events, notably in JAK2 exon 12, MPL exon 10 and CALR exon 9 have been identified. These discoveries have been rapidly incorporated into evolving molecular diagnostic algorithms. Whilst many of these mutations appear to have prognostic implications, establishing MPN diagnosis is of immediate clinical importance with selection, implementation and the continual evaluation of the appropriate laboratory methodology to achieve this diagnosis similarly vital. The advantages and limitations of these approaches in identifying and quantitating the common MPN-associated mutations are considered herein with particular regard to their clinical utility. The evolution of molecular diagnostic applications and platforms has occurred in parallel with the discovery of MPN-associated mutations, and it therefore appears likely that emerging technologies such as next-generation sequencing and digital PCR will in the future play an increasing role in the molecular diagnosis of MPN.
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http://dx.doi.org/10.1111/ejh.12578DOI Listing
October 2015

Genetic variation at MECOM, TERT, JAK2 and HBS1L-MYB predisposes to myeloproliferative neoplasms.

Nat Commun 2015 Apr 7;6:6691. Epub 2015 Apr 7.

1] Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK [2] Wessex Regional Genetics Laboratory, Salisbury District Hospital, Salisbury SP2 8BJ, UK.

Clonal proliferation in myeloproliferative neoplasms (MPN) is driven by somatic mutations in JAK2, CALR or MPL, but the contribution of inherited factors is poorly characterized. Using a three-stage genome-wide association study of 3,437 MPN cases and 10,083 controls, we identify two SNPs with genome-wide significance in JAK2(V617F)-negative MPN: rs12339666 (JAK2; meta-analysis P=1.27 × 10(-10)) and rs2201862 (MECOM; meta-analysis P=1.96 × 10(-9)). Two additional SNPs, rs2736100 (TERT) and rs9376092 (HBS1L/MYB), achieve genome-wide significance when including JAK2(V617F)-positive cases. rs9376092 has a stronger effect in JAK2(V617F)-negative cases with CALR and/or MPL mutations (Breslow-Day P=4.5 × 10(-7)), whereas in JAK2(V617F)-positive cases rs9376092 associates with essential thrombocythemia (ET) rather than polycythemia vera (allelic χ(2) P=7.3 × 10(-7)). Reduced MYB expression, previously linked to development of an ET-like disease in model systems, associates with rs9376092 in normal myeloid cells. These findings demonstrate that multiple germline variants predispose to MPN and link constitutional differences in MYB expression to disease phenotype.
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http://dx.doi.org/10.1038/ncomms7691DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4396373PMC
April 2015

Downregulation of the Wnt inhibitor CXXC5 predicts a better prognosis in acute myeloid leukemia.

Blood 2015 May 24;125(19):2985-94. Epub 2015 Mar 24.

Department of Medical and Molecular Genetics, King's College London, Faculty of Life Sciences and Medicine, London, United Kingdom;

The gene CXXC5 on 5q31 is frequently deleted in acute myeloid leukemia (AML) with del(5q), suggesting that inactivation of CXXC5 might play a role in leukemogenesis. Here, we investigated the functional and prognostic implications of CXXC5 expression in AML. CXXC5 mRNA was downregulated in AML with MLL rearrangements, t(8;21) and GATA2 mutations. As a mechanism of CXXC5 inactivation, we found evidence for epigenetic silencing by promoter methylation. Patients with CXXC5 expression below the median level had a lower relapse rate (45% vs 59%; P = .007) and a better overall survival (OS, 46% vs 28%; P < .001) and event-free survival (EFS, 36% vs 21%; P < .001) at 5 years, independent of cytogenetic risk groups and known molecular risk factors. In gene-expression profiling, lower CXXC5 expression was associated with upregulation of cell-cycling genes and co-downregulation of genes implicated in leukemogenesis (WT1, GATA2, MLL, DNMT3B, RUNX1). Functional analyses demonstrated CXXC5 to inhibit leukemic cell proliferation and Wnt signaling and to affect the p53-dependent DNA damage response. In conclusion, our data suggest a tumor suppressor function of CXXC5 in AML. Inactivation of CXXC5 is associated with different leukemic pathways and defines an AML subgroup with better outcome.
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http://dx.doi.org/10.1182/blood-2014-12-613703DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4463809PMC
May 2015

Minimal residual disease monitoring: a new era for childhood ALL.

Lancet Oncol 2015 Apr 20;16(4):362-4. Epub 2015 Mar 20.

MLL Munich Leukaemia Laboratory, 81377 Munich, Germany. Electronic address:

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http://dx.doi.org/10.1016/S1470-2045(15)70123-3DOI Listing
April 2015

The kinetics of relapse in DEK-NUP214-positive acute myeloid leukemia patients.

Eur J Haematol 2015 Nov 13;95(5):436-41. Epub 2015 Mar 13.

MLL Munich Leukemia Laboratory, Munich, Germany.

Preemptive treatment of relapse of acute myeloid leukemia (AML) holds the promise to improve the prognosis of this currently highly lethal condition. Proposed treatment modalities applicable in preemptive cytoreduction (e.g., demethylating agents or standard chemotherapy) differ substantially in interval from administration to antileukemic effect. The t(6;9) balanced translocation, producing the DEK-NUP214 fusion protein, is seen in only 1% of patients with AML. We hypothesized that in these patients, who relapse with a very high frequency, a more detailed knowledge of leukemic relapse growth kinetics would improve the personalized decision-making regarding re-administration of chemotherapy. Based on standardized quantitative PCR data, we therefore delineated the relapse kinetics in a cohort of 27 relapsing DEK-NUP214-positive patients treated in four different European countries. The prerelapse leukemic burden increased with a median doubling time of 13 d (range: 5-51 d, median: 0.71 logs/month, range: 0.18-1.91 logs/month), with FLT3-ITD-positive patients relapsing significantly faster than FLT3-ITD-negative ones (median: 0.9 vs. 0.6 logs/month, Wilcoxon rank sum test, P = 0.041). Peripheral blood and bone marrow were equally useful for minimal residual disease (MRD) detection, and thus, we found that with sampling intervals of 2 months, 94% of relapses would be detected with a median time from MRD detection to hematological relapse of 64 d. In conclusion, this data provide algorithms for handling the rare patients with DEK-NUP214-positive AML allowing for planning of both MRD follow-up and, upon molecular relapse, the timing of cytoreduction or possibly transplant procedures.
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http://dx.doi.org/10.1111/ejh.12511DOI Listing
November 2015

AML with gain of chromosome 8 as the sole chromosomal abnormality (+8sole) is associated with a specific molecular mutation pattern including ASXL1 mutations in 46.8% of the patients.

Leuk Res 2015 Mar 16;39(3):265-72. Epub 2014 Dec 16.

MLL Munich Leukemia Laboratory, Munich, Germany(1). Electronic address:

Trisomy 8 is the most frequent cytogenetically gained aberration in AML. We compared 79 adult de novo AML with trisomy 8 as the sole cytogenetic abnormality (+8sole) to 511 normal karyotype AML patients (NK). +8sole patients were older (p=0.013), presented lower WBC counts (p=0.010), harbored more often ASXL1 mutations (p<0.001) and RUNX1 mutations (p=0.009), but less frequent FLT3-ITD (p=0.038), NPM1 mutations (p<0.001) and double-mutated CEBPA (p=0.038) than NK patients. No prognostic difference was found between +8sole and NK. With respect to genetic stability we found +8sole was instable, and molecular markers were either stable or gained in number and diversity.
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http://dx.doi.org/10.1016/j.leukres.2014.11.026DOI Listing
March 2015

Multiparameter flow cytometry provides independent prognostic information in patients with suspected myelodysplastic syndromes: A study on 804 patients.

Cytometry B Clin Cytom 2015 May-Jun;88(3):154-64. Epub 2015 Mar 24.

MLL Munich Leukemia Laboratory, Munich, Germany.

Diagnosis of myelodysplastic syndromes (MDS) relies on well-defined cytomorphologic criteria but is challenging in a significant number of patients. The detection of aberrant antigen expression by multiparameter flow cytometry (MFC) is considered a promising tool to improve MDS diagnostics. We prospectively analyzed 804 unselected patients sent with suspected MDS for correlation of MFC findings with overall survival (OS) in the context of cytomorphologic and cytogenetic findings. Patients with evidence of MDS by MFC had a significantly worse OS as compared to those without (OS at 2 years, 71.2% vs. 89.4%; P<0.001). The number of aberrantly expressed antigens as a continuous variable was significantly associated with OS [P<0.001, hazards ratio (HR): 1.19 per additional aberrantly expressed antigen]. Multivariate analysis proved a diagnosis of MDS by MFC to be independently associated with OS (P=0.050; HR: 1.42). Furthermore, a diagnosis of MDS by MFC was related to inferior survival within all three cytomorphologically defined subgroups, i.e., proven MDS (median OS, 45.4 vs. 52.8 months, P<0.001), suspected MDS (2-year-OS, 75.0% vs. 82.8%; P=0.062), and MDS excluded (2-year-OS, 63.5% vs. 92.8%, P=0.020). Our data clearly demonstrate that, in the assessment of cytopenic patients with suspected MDS, a diagnosis of MDS by MFC is independently associated with OS, which had been shown in previous studies for today's standard diagnostic parameters cytomorphology and cytogenetics. MFC may, therefore, be considered an additional tool in the diagnostic workup of patients with suspected MDS.
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http://dx.doi.org/10.1002/cyto.b.21224DOI Listing
January 2016

RAS signaling promotes resistance to JAK inhibitors by suppressing BAD-mediated apoptosis.

Sci Signal 2014 Dec 23;7(357):ra122. Epub 2014 Dec 23.

Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA.

Myeloproliferative neoplasms (MPNs) frequently have an activating mutation in the gene encoding Janus kinase 2 (JAK2). Thus, targeting the pathway mediated by JAK and its downstream substrate, signal transducer and activator of transcription (STAT), may yield clinical benefit for patients with MPNs containing the JAK2(V617F) mutation. Although JAK inhibitor therapy reduces splenomegaly and improves systemic symptoms in patients, this treatment does not appreciably reduce the number of neoplastic cells. To identify potential mechanisms underlying this inherent resistance phenomenon, we performed pathway-centric, gain-of-function screens in JAK2(V617F) hematopoietic cells and found that the activation of the guanosine triphosphatase (GTPase) RAS or its effector pathways [mediated by the kinases AKT and ERK (extracellular signal-regulated kinase)] renders cells insensitive to JAK inhibition. Resistant MPN cells became sensitized to JAK inhibitors when also exposed to inhibitors of the AKT or ERK pathways. Mechanistically, in JAK2(V617F) cells, a JAK2-mediated inactivating phosphorylation of the proapoptotic protein BAD [B cell lymphoma 2 (BCL-2)-associated death promoter] promoted cell survival. In sensitive cells, exposure to a JAK inhibitor resulted in dephosphorylation of BAD, enabling BAD to bind and sequester the prosurvival protein BCL-XL (BCL-2-like 1), thereby triggering apoptosis. In resistant cells, RAS effector pathways maintained BAD phosphorylation in the presence of JAK inhibitors, yielding a specific dependence on BCL-XL for survival. In patients with MPNs, activating mutations in RAS co-occur with the JAK2(V617F) mutation in the malignant cells, suggesting that RAS effector pathways likely play an important role in clinically observed resistance.
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http://dx.doi.org/10.1126/scisignal.2005301DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4353591PMC
December 2014

Analysis for loss of heterozygosity on chromosome arm 13q by STR analysis or SNP sequencing can replace analysis of FLT3-ITD to detect patients with prognostically adverse AML.

Genes Chromosomes Cancer 2014 Dec 3;53(12):1008-17. Epub 2014 Sep 3.

MLL Munich Leukemia Laboratory, Munich, Germany.

We aimed at developing novel assays for Loss of Heterozygosity (LOH) detection on 13q as a substitute for FLT3-ITD analysis to identify acute myeloid leukemia (AML) patients with high risk of shorter survival. To this aim, we first analyzed a selected cohort of 185 patients with (n = 138) or without (n = 47) FLT3-ITD by short tandem repeat (STR) analysis for 13q LOH. In 46 of 138 FLT3-ITD positive cases, a FLT3-ITD/FLT3wt ratio of ≥ 1 was measured indicating LOH. Applying analysis with a combination of five different STR markers, a threshold of an STR allelic ratio of >65% allows the identification of LOH in 40/46 (87%) samples. Survival analysis revealed significantly inferior outcome in patients with LOH as detected by STR analysis (event free survival (EFS): no LOH: 13.3 months versus LOH: 4.5 months, p < 0.001; overall survival (OS): no LOH: 35.8 months versus LOH: 9.7 months, p = 0.001). In multivariate Cox regression analysis, 13q LOH was found to be an independent adverse parameter for EFS and OS (p = 0.003 and p < 0.001, respectively) besides age and white blood cell count. Thus, the prognostic impact of 13q LOH is nearly identical to the one of FLT3-ITD/FLT3wt load of ≥ 1 and thus is a feasible alternative to identify respective patients with high risk AML. In a second approach, a cohort of 91 patients was subjected to a proof-of-principle study of applying single nucleotide polymorphism analysis by next generation amplicon sequencing for detection of LOH. 53/91 cases had LOH and 50 were identified with this new method resulting in a positive detection rate of 94.3%.
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http://dx.doi.org/10.1002/gcc.22210DOI Listing
December 2014

Quantification of rare NPM1 mutation subtypes by digital PCR.

Br J Haematol 2014 Dec 18;167(5):710-4. Epub 2014 Jul 18.

MLL Munich Leukaemia Laboratory, Munich, Germany.

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http://dx.doi.org/10.1111/bjh.13038DOI Listing
December 2014

Equivalence of BCR-ABL transcript levels with complete cytogenetic remission in patients with chronic myeloid leukemia in chronic phase.

J Cancer Res Clin Oncol 2014 Nov 22;140(11):1965-9. Epub 2014 Jun 22.

Institut für Medizinische Informationsverarbeitung, Biometrie und Epidemiologie, Ludwig-Maximilians-Universität, Munich, Germany.

Purpose: Chronic myeloid leukemia (CML) patients are monitored by both cytogenetic and molecular assessments, although present guidelines appear to switch from cytogenetic to molecular criteria. Due to the increasing use of molecular measurements, it was the aim of this work to identify a BCR-ABL level according to the international scale (BCR-ABL(IS)) as an equivalent substitute for complete cytogenetic remission (CCyR).

Methods: In total, 1,329 paired data from 557 patients of the German CML-Study IV were evaluated. The data set was divided into a learning set and a validation set. The best cutoff was determined applying a minimal p value approach to the Fisher test.

Results: In the learning set, we found BCR-ABL(IS) values between 0.2 and 1.1 % were well suited for predicting a CCyR. In the validation set, the cutoff level of 1 % led to a mean concordance rate of 90.1 %.

Conclusions: Our results suggest that there is no one-to-one cutoff for BCR-ABL(IS) representing CCyR, but we advise to use the 1 % BCR-ABL(IS) in order to avoid misclassification of CCyR patients.
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http://dx.doi.org/10.1007/s00432-014-1746-8DOI Listing
November 2014

Distinct characteristics of e13a2 versus e14a2 BCR-ABL1 driven chronic myeloid leukemia under first-line therapy with imatinib.

Haematologica 2014 Sep 16;99(9):1441-7. Epub 2014 May 16.

III. Medizinische Klinik - Hämatologie und Onkologie, Universitätsmedizin Mannheim, Germany

The vast majority of chronic myeloid leukemia patients express a BCR-ABL1 fusion gene mRNA encoding a 210 kDa tyrosine kinase which promotes leukemic transformation. A possible differential impact of the corresponding BCR-ABL1 transcript variants e13a2 ("b2a2") and e14a2 ("b3a2") on disease phenotype and outcome is still a subject of debate. A total of 1105 newly diagnosed imatinib-treated patients were analyzed according to transcript type at diagnosis (e13a2, n=451; e14a2, n=496; e13a2+e14a2, n=158). No differences regarding age, sex, or Euro risk score were observed. A significant difference was found between e13a2 and e14a2 when comparing white blood cells (88 vs. 65 × 10(9)/L, respectively; P<0.001) and platelets (296 vs. 430 × 10(9)/L, respectively; P<0.001) at diagnosis, indicating a distinct disease phenotype. No significant difference was observed regarding other hematologic features, including spleen size and hematologic adverse events, during imatinib-based therapies. Cumulative molecular response was inferior in e13a2 patients (P=0.002 for major molecular response; P<0.001 for MR4). No difference was observed with regard to cytogenetic response and overall survival. In conclusion, e13a2 and e14a2 chronic myeloid leukemia seem to represent distinct biological entities. However, clinical outcome under imatinib treatment was comparable and no risk prediction can be made according to e13a2 versus e14a2 BCR-ABL1 transcript type at diagnosis. (clinicaltrials.gov identifier:00055874).
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http://dx.doi.org/10.3324/haematol.2013.096537DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4562532PMC
September 2014

TP53 mutations occur in 15.7% of ALL and are associated with MYC-rearrangement, low hypodiploidy, and a poor prognosis.

Blood 2014 Jul 14;124(2):251-8. Epub 2014 May 14.

Munich Leukemia Laboratory, Munich, Germany.

TP53 is the most extensively studied gene in cancer. However, data on frequency and the prognostic impact of TP53 mutations in acute lymphoblastic leukemia (ALL) remain scarce. Thus, we aimed at identifying the mutation frequency of TP53, its association with cytogenetic subgroups, and its impact on survival in a large cohort of 625 patients with ALL. Our data revealed an overall mutation incidence of 15.7%, which increases with age. Correlation with cytogenetic subgroups showed that mutations were most frequent in ALL with low hypodiploidy or MYC-rearrangements. Furthermore, for a large number of patients, both TP53 alleles were altered, either by 2 TP53 mutations (12%) or by a TP53 mutation and a TP53 deletion in the second allele (39%). A high TP53 mutation load was correlated to low hypodiploidy, high hyperdiploidy, and a complex karyotype. Moreover, a higher mutation load was found in B-lineage ALL compared with T-lineage ALL. Similar to other cancers, the median overall survival was significantly shorter in patients with TP53 mutation compared with patients with wild-type TP53. This effect was especially pronounced when both TP53 alleles were affected, either by 2 TP53 mutations or by both a mutation and an accompanying TP53 deletion.
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http://dx.doi.org/10.1182/blood-2014-02-558833DOI Listing
July 2014