Publications by authors named "Nicole Naumann"

31 Publications

Low risk of contrast media induced hypersensitivity reactions in all subtypes of systemic mastocytosis.

Ann Allergy Asthma Immunol 2021 Oct 9. Epub 2021 Oct 9.

Clinic of Clinical Radiology and Nuclear Medicine, University Hospital Mannheim, Heidelberg University, Mannheim, Germany. Electronic address:

Background: Patients with SM are at increased risk of hypersensitivity reactions. Although hymenoptera venoms are the predominant triggers, cases of CMIHR have also been reported and prophylactic premedication is often performed. However, data from larger series are limited and differences between indolent and advanced systemic mastocytosis have not yet been investigated.

Objective: To determine the incidence and severity of CMIHR in all subtypes of SM.

Methods: We analyzed 162 adult patients with SM (ISM, n=65; advSM, n=97). Firstly, the cumulative incidence of CMIHR was retrospectively assessed in the patient's history. Secondly, at our institution, patients underwent 332 CM-enhanced imagings including 80 CT scans with iodine-based contrast agent and 252 MRI with gadoliniumbased contrast agent and tolerance was assessed.

Results: Previous CMIHRs to CT (vomiting, n=1, erythema, n=1, cardiovascular shock, n=1) and MRI (dyspnea, n=1, cardiovascular shock, n=1) had been reported by 4/162 (2.5%) patients (ISM, n=3; advSM, n=1). In contrast, during or after 332 CM-enhanced CT/MRI examinations at our institution, no CMIHRs were reported. Premedication was solely given to 3 patients prior to CT scans, including one with previous CMIHR, who tolerated the imaging well.

Conclusion: We conclude that i) there is a significant discrepancy between perception and prevalence of hypersensitivity reactions to CM in SM, ii) reactions are scarce in ISM and even rarer in advSM, iii) in SM patients without previous history of CM hypersensitivity, prophylactic premedication prior to CM enhanced-CT/MRI is dispensable.
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http://dx.doi.org/10.1016/j.anai.2021.10.004DOI Listing
October 2021

Clinical and histopathological features of myeloid neoplasms with concurrent Janus kinase 2 (JAK2) V617F and KIT proto-oncogene, receptor tyrosine kinase (KIT) D816V mutations.

Br J Haematol 2021 Jul 1;194(2):344-354. Epub 2021 Jun 1.

Haematology and Oncology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.

We report on 45 patients with myeloid neoplasms and concurrent Janus kinase 2 (JAK2) V617F and KIT proto-oncogene, receptor tyrosine kinase (KIT) D816V (JAK2 /KIT ) mutations, which are individually identified in >60% of patients with classical myeloproliferative neoplasms (MPN) and >90% of patients with systemic mastocytosis (SM) respectively. In SM, the concurrent presence of a clonal non-mast cell neoplasm [SM with associated haematological neoplasm (SM-AHN)] usually constitutes a distinct subtype associated with poor survival. All 45 patients presented with a heterogeneous combination of clinical/morphological features typical of the individual disorders (e.g. leuco-/erythro-/thrombocytosis and elevated lactate dehydrogenase for MPN; elevated serum tryptase and alkaline phosphatase for SM). Overlapping features identified in 70% of patients included splenomegaly, cytopenia(s), bone marrow fibrosis and additional somatic mutations. Molecular dissection revealed discordant development of variant allele frequency for both mutations and absence of concurrently positive single-cell derived colonies, indicating disease evolution in two independent clones rather than monoclonal disease in >60% of patients examined. Overall survival of JAK2 /KIT patients without additional somatic high-risk mutations [HRM, e.g. in serine and arginine-rich splicing factor 2 (SRSF2), additional sex combs like-1 (ASXL1) or Runt-related transcription factor 1 (RUNX1)] at 5 years was 77%, indicating that the mutual impact of JAK2 V617F and KIT D816V on prognosis is fundamentally different from the adverse impact of additional HRM in the individual disorders.
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http://dx.doi.org/10.1111/bjh.17567DOI Listing
July 2021

Adverse Prognostic Impact of the D816V Transcriptional Activity in Advanced Systemic Mastocytosis.

Int J Mol Sci 2021 Mar 4;22(5). Epub 2021 Mar 4.

Department of Hematology and Oncology, University Hospital Mannheim, Heidelberg University, 68167 Mannheim, Germany.

In systemic mastocytosis (SM), qualitative and serial quantitative assessment of the D816V mutation is of diagnostic and prognostic relevance. We investigated peripheral blood and bone marrow samples of 161 patients (indolent SM (ISM), = 40; advanced SM, AdvSM, = 121) at referral and during follow-up for the D816V variant allele frequency (VAF) at the DNA-level and the D816V expressed allele burden (EAB) at the RNA-level. A round robin test with four participating laboratories revealed an excellent correlation ( > 0.99, > 0.98) between three different DNA-assays. VAF and EAB strongly correlated in ISM ( 0.91, coefficient of determination, 0.84) but only to a lesser extent in AdvSM ( 0.71; = 0.5). However, as compared to an EAB/VAF ratio ≤2 (cohort A, 77/121 patients, 64%) receiver operating characteristic (ROC) analysis identified an EAB/VAF ratio of >2 (cohort B, 44/121 patients, 36%) as predictive for an advanced phenotype and a significantly inferior median survival (3.3 vs. 11.7 years; = 0.005). In terms of overall survival, Cox-regression analysis was only significant for the EAB/VAF ratio >2 ( = 0.006) but not for VAF or EAB individually. This study demonstrates for the first time that the transcriptional activity of D816V may play an important role in the pathophysiology of SM.
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http://dx.doi.org/10.3390/ijms22052562DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7961551PMC
March 2021

Importance of Adequate Diagnostic Workup for Correct Diagnosis of Advanced Systemic Mastocytosis.

J Allergy Clin Immunol Pract 2020 10 15;8(9):3121-3127.e1. Epub 2020 May 15.

Department of Hematology and Oncology, University Hospital Mannheim, Heidelberg University, Mannheim, Germany. Electronic address:

Background: Little is known about the epidemiology of advanced systemic mastocytosis (advSM).

Objectives: To investigate epidemiologic features and diagnostic pitfalls of advSM in Germany.

Methods: Therefore, 140 patients from a single German reference center of the European Competence Network on Mastocytosis between 2003 and 2018 were analyzed.

Results: The patients' median age was 68 years (range, 26-86 years), and male versus female ratio was 2:1. An elevated serum tryptase, a KIT D816 mutation, and additional somatic mutations, for example, in SRSF2, ASXL1, or RUNX1, were identified in 95%, 91%, and 74% of patients, respectively. Median overall survival was 3.5 years (range, 0.03-14.3 years; male vs female 2.6 vs 4.2 years; P = .02). Two categories of misdiagnoses were identified in 51 of 140 (36%) patients: First, systemic mastocytosis (SM) was overlooked in 28 of 140 (20%) patients primarily diagnosed with various subtypes of myeloid neoplasms. Second, 23 of 140 (16%) patients were diagnosed with supposed progression from indolent SM to advSM; however, combination of an elevated KIT D816V variant allele frequency in peripheral blood (n = 22), monocytosis (n = 9), eosinophilia (n = 6), and/or mutations in SRSF2, ASXL1, or RUNX1 (n = 10) suggest that distinct signs of potential advSM were overlooked in virtually all patients. Based on locally diagnosed patients in an area of 2.5 million inhabitants, but obviously without considering more, yet unrecognized cases, the incidence and prevalence of advSM is at least 0.8 and 5.2, respectively, per 1 million inhabitants.

Conclusions: Adequate analyses of tryptase levels, bone marrow morphology, and genetics in patients with myeloid neoplasms or SM would help to prevent the significant underdiagnosis of advSM.
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http://dx.doi.org/10.1016/j.jaip.2020.05.005DOI Listing
October 2020

Response to tyrosine kinase inhibitors in myeloid neoplasms associated with PCM1-JAK2, BCR-JAK2 and ETV6-ABL1 fusion genes.

Am J Hematol 2020 07 28;95(7):824-833. Epub 2020 Apr 28.

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

We report on 18 patients with myeloid neoplasms and associated tyrosine kinase (TK) fusion genes on treatment with the TK inhibitors (TKI) ruxolitinib (PCM1-JAK2, n = 8; BCR-JAK2, n = 1) and imatinib, nilotinib or dasatinib (ETV6-ABL1, n = 9). On ruxolitinib (median 24 months, range 2-36 months), a complete hematologic response (CHR) and complete cytogenetic response (CCR) was achieved by five of nine and two of nine patients, respectively. However, ruxolitinib was stopped in eight of nine patients because of primary resistance (n = 3), progression (n = 3) or planned allogeneic stem cell transplantation (allo SCT, n = 2). At a median of 36 months (range 4-78 months) from diagnosis, five of nine patients are alive: four of six patients after allo SCT and one patient who remains on ruxolitinib. In ETV6-ABL1 positive patients, a durable CHR was achieved by four of nine patients (imatinib with one of five, nilotinib with two of three, dasatinib with one of one). Because of inadequate efficacy (lack of hematological and/or cytogenetic/molecular response), six of nine patients (imatinib, n = 5; nilotinib, n = 1) were switched to nilotinib or dasatinib. At a median of 23 months (range 3-60 months) from diagnosis, five of nine patients are in CCR or complete molecular response (nilotinib, n = 2; dasatinib, n = 2; allo SCT, n = 1) while two of nine patients have died. We conclude that (a) responses on ruxolitinib may only be transient in the majority of JAK2 fusion gene positive patients with allo SCT being an important early treatment option, and (b) nilotinib or dasatinib may be more effective than imatinib to induce durable complete remissions in ETV6-ABL1 positive patients.
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http://dx.doi.org/10.1002/ajh.25825DOI Listing
July 2020

Intratumoral Heterogeneity and Longitudinal Changes in Gene Expression Predict Differential Drug Sensitivity in Newly Diagnosed and Recurrent Glioblastoma.

Cancers (Basel) 2020 Feb 24;12(2). Epub 2020 Feb 24.

Institute of Personalized Medicine, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia.

Inevitable recurrence after radiochemotherapy is the major problem in the treatment of glioblastoma, the most prevalent type of adult brain malignancy. Glioblastomas are notorious for a high degree of intratumor heterogeneity manifest through a diversity of cell types and molecular patterns. The current paradigm of understanding glioblastoma recurrence is that cytotoxic therapy fails to target effectively glioma stem cells. Recent advances indicate that therapy-driven molecular evolution is a fundamental trait associated with glioblastoma recurrence. There is a growing body of evidence indicating that intratumor heterogeneity, longitudinal changes in molecular biomarkers and specific impacts of glioma stem cells need to be taken into consideration in order to increase the accuracy of molecular diagnostics still relying on readouts obtained from a single tumor specimen. : This study integrates a multisampling strategy, longitudinal approach and complementary transcriptomic investigations in order to identify transcriptomic traits of recurrent glioblastoma in whole-tissue specimens of glioblastoma or glioblastoma stem cells. In this study, 128 tissue samples of 44 tumors including 23 first diagnosed, 19 recurrent and 2 secondary recurrent glioblastomas were analyzed along with 27 primary cultures of glioblastoma stem cells by RNA sequencing. A novel algorithm was used to quantify longitudinal changes in pathway activities and model efficacy of anti-cancer drugs based on gene expression data. : Our study reveals that intratumor heterogeneity of gene expression patterns is a fundamental characteristic of not only newly diagnosed but also recurrent glioblastomas. Evidence is provided that glioblastoma stem cells recapitulate intratumor heterogeneity, longitudinal transcriptomic changes and drug sensitivity patterns associated with the state of recurrence. : Our results provide a transcriptional rationale for the lack of significant therapeutic benefit from temozolomide in patients with recurrent glioblastoma. Our findings imply that the spectrum of potentially effective drugs is likely to differ between newly diagnosed and recurrent glioblastomas and underscore the merits of glioblastoma stem cells as prognostic models for identifying alternative drugs and predicting drug response in recurrent glioblastoma. With the majority of recurrent glioblastomas being inoperable, glioblastoma stem cell models provide the means of compensating for the limited availability of recurrent glioblastoma specimens.
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http://dx.doi.org/10.3390/cancers12020520DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7072286PMC
February 2020

DNA Damage and DNA Damage Response in Chronic Myeloid Leukemia.

Int J Mol Sci 2020 Feb 11;21(4). Epub 2020 Feb 11.

Department of Hematology and Oncology, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany.

DNA damage and alterations in the DNA damage response (DDR) are critical sources of genetic instability that might be involved in BCR-ABL1 kinase-mediated blastic transformation of chronic myeloid leukemia (CML). Here, increased DNA damage is detected by γH2AX foci analysis in peripheral blood mononuclear cells (PBMCs) of de novo untreated chronic phase (CP)-CML patients ( = 5; 2.5 γH2AX foci per PBMC ± 0.5) and blast phase (BP)-CML patients ( = 3; 4.4 γH2AX foci per PBMC ± 0.7) as well as CP-CML patients with loss of major molecular response (MMR) ( = 5; 1.8 γH2AX foci per PBMC ± 0.4) when compared to DNA damage in PBMC of healthy donors ( = 8; 1.0 γH2AX foci per PBMC ± 0.1) and CP-CML patients in deep molecular response or MMR ( = 26; 1.0 γH2AX foci per PBMC ± 0.1). Progressive activation of erroneous non-homologous end joining (NHEJ) repair mechanisms during blastic transformation in CML is indicated by abundant co-localization of γH2AX/53BP1 foci, while a decline of the DDR is suggested by defective expression of (p-)ATM and (p-)CHK2. In summary, our data provide evidence for the accumulation of DNA damage in the course of CML and suggest ongoing DNA damage, erroneous NHEJ repair mechanisms, and alterations in the DDR as critical mediators of blastic transformation in CML.
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http://dx.doi.org/10.3390/ijms21041177DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7072846PMC
February 2020

Treatment-free remission in FIP1L1-PDGFRA-positive myeloid/lymphoid neoplasms with eosinophilia after imatinib discontinuation.

Blood Adv 2020 Feb;4(3):440-443

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

FIP1L1-PDGFRA-positive myeloid/lymphoid neoplasms with eosinophilia (MLN-eo) are exquisitely sensitive to imatinib. Almost all patients achieve a complete molecular remission (CMR) by nested reverse transcription polymerase chain reaction, which can be maintained with low-dose imatinib (eg, 3 × 100 mg/wk). Because imatinib can be safely stopped in a substantial proportion of patients with BCR-ABL1-positive CML, we sought to analyze the clinical and molecular follow-up of 12 FIP1L1-PDGFRA-positive patients with MLN-eo in chronic phase who discontinued imatinib after achievement of a CMR. Median time of treatment and median time of CMR before imatinib discontinuation (last dose at 3 × 100 mg/wk, n = 8; or 100 mg/d, n = 4) were 80 (range, 43-175) and 66 (range, 37-174) months, respectively. A molecular relapse was observed in 4 patients after 10, 22 (n = 2), and 24 months. A second CMR was achieved in 3 patients after 3, 4, and 21 months. Eight patients (62%) are in ongoing CMR (median, 17 months; range, 3-71 months). Molecular relapse-free survival was 91% at 12 months and 65% at 24 months. No significant differences (eg, dose and duration of imatinib treatment or duration of CMR before imatinib discontinuation) were identified between patients with and without molecular relapse. Our data demonstrate that imatinib can be safely stopped in FIP1L1-PDGFRA-positive MLN-eo because of a high treatment-free remission at 12 and 24 months and because most patients achieve a rapid second CMR after restart of imatinib.
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http://dx.doi.org/10.1182/bloodadvances.2019001111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7013256PMC
February 2020

An increased bone mineral density is an adverse prognostic factor in patients with systemic mastocytosis.

J Cancer Res Clin Oncol 2020 Apr 24;146(4):945-951. Epub 2020 Jan 24.

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

Purpose: Systemic mastocytosis (SM) is characterized by the expansion of clonal mast cells that infiltrate various organ systems. The extent of organ infiltration and subsequent organ damage distinguishes between indolent SM (ISM) defined by a nearly normal life expectancy and advanced SM (AdvSM) defined by poor prognosis. In ISM, measurement of the bone mineral density (BMD) frequently reveals osteoporosis. In contrast, the clinical implication of an increased BMD and osteosclerosis remains unclear.

Methods: BMD was evaluated in 61 patients with mastocytosis (ISM, n = 29, 48%; AdvSM, n = 32, 52%). We correlated the prevalence of osteoporosis, increased BMD and osteosclerosis with clinical parameters, disease variant and prognosis.

Results: Osteoporosis was detected in 11/29 (38%) patients with ISM but only in 2/32 (6%) patients with AdvSM (p = 0.004). An increased BMD was detected in 1/29 (3%) patients with ISM and 24/32 (75%) patients with AdvSM (p < 0.001) while osteosclerosis was only detected in AdvSM patients (16/32, 50%). AdvSM patients with increased BMD had higher levels of bone marrow mast cell infiltration, higher serum tryptase and alkaline phosphatase levels compared to ISM as well as higher number of high-molecular risk mutations (p < 0.05). In addition, we found that the prognosis of AdvSM patients with increased BMD is inferior compared to those without increased BMD (median overall survival 3.6 years versus not reached, p = 0.031).

Conclusions: Osteoporosis is a common feature in ISM but not in AdvSM. An increased BMD is frequently present in AdvSM but not in ISM and is associated with more advanced disease and inferior outcome.
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http://dx.doi.org/10.1007/s00432-019-03119-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7085471PMC
April 2020

Antileukemic Efficacy in Vitro of Talazoparib and APE1 Inhibitor III Combined with Decitabine in Myeloid Malignancies.

Cancers (Basel) 2019 Oct 3;11(10). Epub 2019 Oct 3.

Department of Hematology and Oncology, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany.

Malignant hematopoietic cells of myelodysplastic syndromes (MDS)/chronic myelomonocytic leukemias (CMML) and acute myeloid leukemias (AML) may be vulnerable to inhibition of poly(ADP ribose) polymerase 1/2 (PARP1/2) and apurinic/apyrimidinic endonuclease 1 (APE1). PARP1/2 and APE1 are critical enzymes involved in single-strand break repair and base excision repair, respectively. Here, we investigated the cytotoxic efficacy of talazoparib and APE1 inhibitor III, inhibitors of PARP1/2 and APE1, in primary CD34+ MDS/CMML cell samples ( = 8; 4 MDS and 4 CMML) and in primary CD34+ or CD34- AML cell samples ( = 18) in comparison to healthy CD34+ donor cell samples ( = 8). Strikingly, talazoparib and APE1 inhibitor III demonstrated critical antileukemic efficacy in selected MDS/CMML and AML cell samples. Low doses of talazoparib and APE1 inhibitor III further increased the cytotoxic efficacy of decitabine in MDS/CMML and AML cells. Moreover, low doses of APE1 inhibitor III increased the cytotoxic efficacy of talazoparib in MDS/CMML and AML cells. In summary, talazoparib and APE1 inhibitor III demonstrated substantial antileukemic efficacy as single agents, in combination with decitabine, and combined with each other. Hence, our findings support further investigation of these agents in sophisticated clinical trials.
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http://dx.doi.org/10.3390/cancers11101493DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6826540PMC
October 2019

MARS: Mutation-Adjusted Risk Score for Advanced Systemic Mastocytosis.

J Clin Oncol 2019 11 11;37(31):2846-2856. Epub 2019 Sep 11.

University Hospital Mannheim, Heidelberg University, Mannheim, Germany.

Purpose: To develop a risk score for patients with advanced systemic mastocytosis (AdvSM) that integrates clinical and mutation characteristics.

Patients And Methods: The study included 383 patients with AdvSM from the German Registry on Disorders of Eosinophils and Mast Cells (training set; n = 231) and several centers for mastocytosis in the United States and Europe, all within the European Competence Network on Mastocytosis (validation set; n = 152). A Cox multivariable model was used to select variables that were predictive of overall survival (OS).

Results: In multivariable analysis, the following risk factors were identified as being associated with OS: age greater than 60 years, anemia (hemoglobin < 10 g/dL), thrombocytopenia (platelets < 100 × 10/L), presence of one high molecular risk gene mutation (ie, in , , and/or ), and presence of two or more high molecular risk gene mutations. By assigning hazard ratio-weighted points to these variables, the following three risk categories were defined: low risk (median OS, not reached), intermediate risk (median OS, 3.9 years; 95% CI, 2.1 to 5.7 years), and high risk (median OS, 1.9 years; 95% CI, 1.3 to 2.6 years; < .001). The mutation-adjusted risk score (MARS) was independent of the WHO classification and was confirmed in the independent validation set. During a median follow-up time of 2.2 years (range, 0 to 23 years), 63 (16%) of 383 patients experienced a leukemic transformation to secondary mast cell leukemia (32%) or secondary acute myeloid leukemia (68%). The MARS was also predictive for leukemia-free survival ( < .001).

Conclusion: The MARS is a validated, five-parameter, WHO-independent prognostic score that defines three risk groups among patients with AdvSM and may improve up-front treatment stratification for these rare hematologic neoplasms.
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http://dx.doi.org/10.1200/JCO.19.00640DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6823885PMC
November 2019

Inhibitory effects of midostaurin and avapritinib on myeloid progenitors derived from patients with KIT D816V positive advanced systemic mastocytosis.

Leukemia 2019 05 25;33(5):1195-1205. Epub 2019 Mar 25.

Department of Hematology and Oncology, University Medical Centre Mannheim, Mannheim, Germany.

Advanced systemic mastocytosis (advSM) is characterized by the presence of an acquired KIT D816V mutation in >90% of patients. In the majority of patients, KIT D816V is not only detected in mast cells but also in other hematopoietic lineages. We sought to investigate the effects of the KIT-inhibitors midostaurin and avapritinib on single-cell-derived myeloid progenitor cells using granulocyte-macrophage colony-forming-units of patients with KIT D816V positive advSM. Colonies obtained prior to treatment were incubated in vitro with midostaurin (n = 10) or avapritinib (n = 11) and showed a marked reduction (≥50%) of KIT D816V positive colonies in 3/10 (30%) and 7/11 (64%) patient samples, respectively. Three of those 7 (43%) avapritinib responders were resistant to midostaurin in both, in vitro and in vivo. Colonies from four patients with high-risk molecular profile and aggressive clinical course were resistant to both drugs. The in vitro activity of midostaurin strongly correlated with clinical and molecular responses, e.g., relative reduction of KIT D816V allele burden and the proportion of KIT D816V positive colonies obtained after six months midostaurin-treatment in vivo. We conclude that the colony inhibition assay provides useful information for prediction of responses on midostaurin and that avapritinib has a superior in vitro activity compared to midostaurin.
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http://dx.doi.org/10.1038/s41375-019-0450-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6756065PMC
May 2019

Diagnostic performance of the molecular BCR-ABL1 monitoring system may impact on inclusion of CML patients in stopping trials.

PLoS One 2019 21;14(3):e0214305. Epub 2019 Mar 21.

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

In chronic myeloid leukemia (CML), the duration of deep molecular response (MR) before treatment cessation (MR4 or deeper, corresponding to BCR-ABL1 ≤ 0.01% on the International Scale (IS)) is considered as a prognostic factor for treatment free remission in stopping trials. MR level determination is dependent on the sensitivity of the monitoring technique. Here, we compared a newly established TaqMan (TM) and our so far routinely used LightCycler (LC) quantitative reverse transcription (qRT)-PCR systems for their ability to achieve the best possible sensitivity in BCR-ABL1 monitoring. We have comparatively analyzed RNA samples from peripheral blood mononuclear cells of 92 randomly chosen patients with CML resembling major molecular remission (MMR) or better and of 128 CML patients after treatment cessation (EURO-SKI stopping trial). While our LC system utilized ABL1, the TM system is based on GUSB as reference gene. We observed 99% concordance with respect to achievement of MMR. However, we found that 34 of the 92 patients monitored by TM/GUSB were re-classified to the next inferior MR log level, especially when LC/ABL1-based results were borderline to thresholds. Thirteen patients BCR-ABL1 negative in LC/ABL1 became positive after TM/GUSB analysis. In the 128 patients included in the EURO-SKI trial identical molecular findings were achieved for 114 patients. However, 14 patients were re-classified to the next inferior log-level by the TM/GUSB combination. Eight of these patients relapsed after treatment cessation; two of them were re-classified from MR4 to MMR and therefore did not meet inclusion criteria anymore. In conclusion, we consider both methods as comparable and interchangeable in terms of achievement of MMR and of longitudinal evaluation of clinical courses. However, in LC/ABL1 negative samples, slightly enhanced TM/GUSB sensitivity may lead to inferior classification of clinical samples in the context of TFR.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0214305PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6428315PMC
December 2019

KIT D816 mutated/CBF-negative acute myeloid leukemia: a poor-risk subtype associated with systemic mastocytosis.

Leukemia 2019 05 11;33(5):1124-1134. Epub 2019 Jan 11.

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

KIT D816 mutations (KIT D816) are strongly associated with systemic mastocytosis (SM) but are also detectable in acute myeloid leukemia (AML), where they represent an adverse prognostic factor in combination with core binding factor (CBF) fusion genes. Here, we evaluated the clinical and molecular features of KIT D816/CBF-negative (CBF) AML, a previously uncharacterized combination. All KIT D816/CBF cases (n = 40) had histologically proven SM with associated AML (SM-AML). Molecular analyses revealed at least one additional somatic mutation (median, n = 3) beside KIT D816 (e.g., SRSF2, 38%; ASXL1, 31%; RUNX1, 34%) in 32/32 (100%) patients. Secondary AML evolved in 29/40 (73%) patients from SM ± associated myeloid neoplasm. Longitudinal molecular and cytogenetic analyses revealed the acquisition of new mutations and/or karyotype evolution in 15/16 (94%) patients at the time of SM-AML. Median overall survival (OS) was 5.4 months. A screen of two independent AML databases (AML) revealed remarkable similarities between KIT D816/CBF SM-AML and KIT D816/CBF AML (n = 69) with regard to KIT D816 variant allele frequency, mutation profile, aberrant karyotype, and OS suggesting underlying SM in a significant proportion of AML patients. Bone marrow histology and reclassification as SM-AML has important clinical implications regarding prognosis and potential inclusion of KIT inhibitors in treatment concepts.
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http://dx.doi.org/10.1038/s41375-018-0346-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6756067PMC
May 2019

Recurrent activating STAT5B N642H mutation in myeloid neoplasms with eosinophilia.

Leukemia 2019 02 20;33(2):415-425. Epub 2018 Dec 20.

Manchester University NHS FT, Manchester, UK.

Determining the underlying cause of persistent eosinophilia is important for effective clinical management but remains a diagnostic challenge in many cases. We identified STAT5B N642H, an established oncogenic mutation, in 27/1715 (1.6%) cases referred for investigation of eosinophilia. Of the 27 mutated cases, a working diagnosis of hypereosinophilic syndrome (HES; n = 7) or a myeloid neoplasm with eosinophilia (n = 20) had been made prior to the detection of STAT5B N642H. Myeloid panel analysis identified a median of 2 additional mutated genes (range 0-4) with 4 cases having STAT5B N642H as a sole abnormality. STAT5B N642H was absent in cultured T cells of 4/4 positive cases. Individuals with SF3B1 mutations (9/27; 33%) or STAT5B N642H as a sole abnormality had a markedly better overall survival compared to cases with other additional mutations (median 65 months vs. 14 months; hazard ratio = 8.1; P < 0.001). The overall survival of STAT5B-mutated HES cases was only 30 months, suggesting that these cases should be reclassified as chronic eosinophilic leukemia, not otherwise specified (CEL-NOS). The finding of STAT5B N642H as a recurrent mutation in myeloid neoplasia with eosinophilia provides a new diagnostic and prognostic marker as well as a potential target for therapy.
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http://dx.doi.org/10.1038/s41375-018-0342-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6365490PMC
February 2019

The benefit of quality control charts (QCC) for routine quantitative BCR-ABL1 monitoring in chronic myeloid leukemia.

PLoS One 2018 24;13(4):e0196326. Epub 2018 Apr 24.

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

Quantitative real-time polymerase chain reaction (qRT-PCR) is state of the art in molecular monitoring of minimal residual disease in chronic myeloid leukemia (CML). In this context, maintenance of assay fidelity and detection of technical inaccuracy are crucial. Beside multiple common negative controls for the clinical sample preparations, quality control charts (QCC) are a common validation tool to sustain high process quality by continuously recording of qRT-PCR control parameters. Here, we report on establishment and benefit of QCC in qRT-PCR-based CML diagnostics. The absolute quantification of BCR-ABL1 fusion transcripts in patient samples is based on coamplification of a serially diluted reference plasmid (pME-2). For QCC establishment the measured Ct values of each pME-2 standard dilution (4-400,000) of a test set resembling 21 sequential qRT-PCR experiments were recorded and statistically evaluated. Test set data were used for determination of warning limits (mean +/- 2-fold standard deviation) and control (intervention) limits (mean +/- 3-fold standard deviation) to allow rapid detection of defined out-of-control situations which may require intervention. We have retrospectively analyzed QCC data of 282 sequential qRT-PCR experiments (564 reactions). Data evaluation using QCCs revealed three out-of-control situations that required intervention like experiment repeats, renewal of pME-2 standards, replacement of reagents or personnel re-training. In conclusion, with minimal more effort and hands-on time QCC rank among the best tools to grant high quality and reproducibility in CML routine molecular diagnosis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0196326PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5916859PMC
August 2018

Incidence and prognostic impact of cytogenetic aberrations in patients with systemic mastocytosis.

Genes Chromosomes Cancer 2018 05 19;57(5):252-259. Epub 2018 Feb 19.

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

The clinical behavior of systemic mastocytosis (SM) is strongly associated with activating mutations in KIT (D816V in >80% of cases), with the severity of the phenotype influenced by additional somatic mutations, for example, in SRSF2, ASXL1, or RUNX1. Complex molecular profiles are frequently associated with the presence of an associated hematologic neoplasm (AHN) and an unfavorable clinical outcome. However, little is known about the incidence and prognostic impact of cytogenetic aberrations. We analyzed cytogenetic and molecular characteristics of 109 patients (KIT D816V+, n = 102, 94%) with indolent (ISM, n = 26) and advanced SM (n = 83) with (n = 73, 88%) or without AHN. An aberrant karyotype was identified in SM-AHN (16/73, 22%) patients only. In patients with an aberrant karyotype, additional somatic mutations were identified in 12/16 (75%) patients. Seven of 10 (70%) patients with a poor-risk karyotype, for example, monosomy 7 or complex karyotype, and 1/6 (17%) patients with a good-risk karyotype progressed to secondary acute myeloid leukemia (n = 7) or mast cell leukemia (n = 1) within a median of 40 months (range 2-190, P = .04). In advanced SM, the median overall survival (OS) of poor-risk karyotype patients was significantly shorter than in good-risk/normal karyotype patients (4 vs 39 months; hazard ratio 11.7, 95% CI 5.0-27.3; P < .0001). Additionally, the shortened OS in patients with poor-risk karyotype was independent from the mutation status. In summary, a poor-risk karyotype is an independent prognostic variable in advanced SM. Cytogenetic and molecular analyses should be routinely performed in all patients with advanced SM ± AHN because these investigations greatly support prognostication and treatment decisions.
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http://dx.doi.org/10.1002/gcc.22526DOI Listing
May 2018

Imatinib in myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRB in chronic or blast phase.

Ann Hematol 2017 Sep 19;96(9):1463-1470. Epub 2017 Jul 19.

Department of Hematology and Oncology, University Medical Centre Mannheim, Mannheim, Germany.

We evaluated clinical characteristics and outcome on imatinib of 22 patients with myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRB. Median age was 49 years (range 20-80), 91% were male. Fifteen different PDGFRB fusion genes were identified. Eosinophilia was absent in 4/19 (21%) cases and only 11/19 (58%) cases had eosinophils ≥1.5×10/L. On imatinib, 17/17 (100%) patients in chronic phase achieved complete hematologic remission after median 2 months (range 0-13)​. Complete cytogenetic remission and/or complete molecular remission by RT-PCR were achieved in 12/13 (92%) and 12/14 patients (86%) after median 10 (range 3-34) and 19 months (range 7-110), respectively. In patients with blast phase (myeloid, n = 2; lymphoid, n = 3), treatment included combinations of imatinib (n = 5), intensive chemotherapy (n = 3), and/or allogeneic stem cell transplantation (n = 3). All 3 transplanted patients (complex karyotype, n = 2) experienced early relapse. Initially, patients were treated with imatinib 400 mg/day (n = 15) or 100 mg/day (n = 7), the dose was reduced from 400 mg/day to 100 mg/day during follow-up in 9 patients. After a median treatment of 71 months (range 1-135), the 5-year survival rate was 83%; 4/22 (18%) patients died (chronic phase; n = 2; blast phase, n = 2) due to progression (n = 3) or comorbidity while in remission (n = 1). Of note, 3/4 patients had a complex karyotype. In summary, the most important characteristics of myeloid/lymphoid neoplasms with rearrangement of PDGFRB include (a) male predominance, (b) frequent lack of hypereosinophilia,
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http://dx.doi.org/10.1007/s00277-017-3067-xDOI Listing
September 2017

Response and progression on midostaurin in advanced systemic mastocytosis: D816V and other molecular markers.

Blood 2017 07 19;130(2):137-145. Epub 2017 Apr 19.

Department of Hematology and Oncology, Mannheim University Medical Center, Mannheim, Germany.

In advanced systemic mastocytosis (advSM), disease evolution is often triggered by mutations (D816V in >80% of cases) and by additional mutations (eg, in , , and/or [S/A/R in >60% of cases]). In a recently reported phase 2 study, midostaurin, a multikinase/KIT inhibitor, demonstrated an overall response rate (ORR) of 60% in advSM but biomarkers predictive of response are lacking. We evaluated the impact of molecular markers at baseline and during follow-up in 38 midostaurin-treated advSM patients. The median overall survival (OS) was 30 months (95% confidence interval, 6-54) from start of midostaurin. ORR and OS were significantly different between S/A/R (n = 12) and S/A/R (n = 23) patients (ORR: 75% vs 39%, = .04; OS: = .01, HR 4.5 [1.3-16.2]). Depending on the relative reduction of the D816V expressed allele burden (EAB) at month 6, patients were classified as responders (≥25%, n = 17) or nonresponders (<25%, n = 11). In univariate analyses at month 6, reduction of D816V EAB ≥25%, tryptase ≥50%, and alkaline phosphatase ≥50% were significantly associated with improved OS. In multivariate analysis, only D816V EAB reduction ≥25% remained an independent on-treatment marker for improved OS ( = .004, HR 6.8 [1.8-25.3]). Serial next-generation sequencing analysis of 28 genes in 16 patients revealed acquisition of additional mutations or increasing variant allele frequency in /, , , or associated with progression in 7 patients. In midostaurin-treated advSM patients, the complexity and dynamics of mutational profiles significantly affect response, progression, and prognosis.
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http://dx.doi.org/10.1182/blood-2017-01-764423DOI Listing
July 2017

Increase of DNA damage and alteration of the DNA damage response in myelodysplastic syndromes and acute myeloid leukemias.

Leuk Res 2017 06 21;57:112-118. Epub 2017 Mar 21.

Department of Hematology and Oncology, Medical Faculty Mannheim of the University of Heidelberg, Mannheim, Germany.

Increased DNA damage and alteration of the DNA damage response (DDR) are critical features of genetic instability presumably implicated in pathogenesis of myelodysplastic syndromes (MDS) and acute myeloid leukemias (AML). We used immunofluorescence staining of γH2AX and 53BP1 for analyzing DNA double-strand breaks (DSB) in MDS and AML cell lines, in CD34+ selected cells of normal and MDS bone marrow (including three cases of chronic myelomonocytic leukemias) and in blasts of AML bone marrow. In addition, we screened for activation of the DDR by immunoblotting of p-ATM, p-ATR, p-CHK1, p-CHK2 and p-TP53. As compared to γH2AX foci levels in normal bone marrow samples (0.2 focus per CD34+ cell±0.0; mean±standard error of mean), increased levels of γH2AX foci were detected in 16/16 MDS bone marrow samples (2.8 foci per CD34+ cell±0.5), 18/18 AML bone marrow samples (5.5 foci per blast±0.5), 1/1 MDS cell line (6.4 foci per cell) and 6/6 AML cell lines (12.0 foci per cell±0.6). γH2AX and 53BP1 co-localized in all tested samples forming diffuse, clustered and marginal patterns. Further, DDR proteins were expressed heterogeneously suggesting impairment of the DDR. In summary, our results provide evidence for a continuous increase of DSB across the spectrum from MDS to AML in conjunction with an impaired DDR. Co-localization of γH2AX and 53BP1 indicates promotion of (in)effective nonhomologous end-joining repair mechanisms at sites of DSB. Moreover, γH2AX/53BP1 foci distribution presumably reveals a non-random spatial organization of the genome in MDS and AML.
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http://dx.doi.org/10.1016/j.leukres.2017.03.011DOI Listing
June 2017

The clinical and molecular diversity of mast cell leukemia with or without associated hematologic neoplasm.

Haematologica 2017 06 2;102(6):1035-1043. Epub 2017 Mar 2.

Department of Hematology and Oncology, University Medical Centre Mannheim, Germany

Mast cell leukemia is a rare variant of advanced systemic mastocytosis characterized by at least 20% of mast cells in a bone marrow smear. We evaluated clinical and molecular characteristics of 28 patients with (n=20, 71%) or without an associated hematologic neoplasm. mast cell leukemia was diagnosed in 16 of 28 (57%) patients and secondary mast cell leukemia evolving from other advanced systemic mastocytosis subtypes in 12 of 28 (43%) patients, of which 7 patients progressed while on cytoreductive treatment. Median bone marrow mast cell infiltration was 65% and median serum tryptase was 520 μg/L. C-findings were identified in 26 of 28 (93%) patients. Mutations in (D816V, n=19; D816H/Y, n=5; F522C, n=1) were detected in 25 of 28 (89%) patients and prognostically relevant additional mutations in , or (S/A/R) in 13 of 25 (52%) patients. Overall response rate in 18 treatment-naïve patients was 5 of 12 (42%) on midostaurin and 1 of 6 (17%) on cladribine, and after switch 1 of 4 (25%) on midostaurin and 0 of 3 on cladribine, respectively. S/A/R adversely affected response to treatment and progression to secondary mast cell leukemia (n=6) or acute myeloid leukemia (n=3) while on treatment (<0.05). The median overall survival from mast cell leukemia diagnosis was 17 months as compared to 44 months in a control group of 124 patients with advanced systemic mastocytosis but without mast cell leukemia (=0.03). In multivariate analyses, S/A/R remained the only independent poor prognostic variable predicting overall survival (=0.007). In conclusion, the molecular signature should be determined in all patients with mast cell leukemia because of its significant clinical and prognostic relevance.
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http://dx.doi.org/10.3324/haematol.2017.163964DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5451335PMC
June 2017

Leukocyte DNA damage after reduced and conventional absorbed radiation doses using 3rd generation dual-source CT technology.

Eur J Radiol Open 2016 6;3:134-7. Epub 2016 Jul 6.

Department of Hematology and Oncology, Medical Faculty Mannheim of the University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.

Purpose: Computed tomography (CT) scans are an important source of ionizing irradiation (IR) in medicine that can induce a variety of DNA damage in human tissues. With technological improvements CT scans at reduced absorbed doses became feasible presumably lowering genotoxic side effects.

Materials And Methods: For measuring DNA damage we performed γH2AX foci microscopy in peripheral blood mononuclear cells (PBMC) after exposure to reduced and conventional absorbed radiation doses using 3rd generation dual-source CT (DSCT) technology.

Results: CT scans performed at reduced absorbed doses of 3 mGy induced significant lower levels (p < 0.0001) of DNA damage (0.05 focus per cell ± 0.01 [mean ± standard error of mean]) at 5 min after IR compared to conventional absorbed doses of 15 mGy (0.30 focus per cell ± 0.03). With ongoing DNA repair background γH2AX foci levels (0.05 focus per cell) were approached at 24 h after CT with both protocols.

Conclusion: Our results provide evidence that reduced absorbed doses mediated by adjusted tube current in 3rd generation DSCT induce lower levels of DNA damage in PBMC compared to conventional absorbed doses suggesting a lower genotoxic risk for state-of-the-art tube current reduced CT protocols.
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http://dx.doi.org/10.1016/j.ejro.2016.06.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4939318PMC
July 2016

Impact of centralized evaluation of bone marrow histology in systemic mastocytosis.

Eur J Clin Invest 2016 May 21;46(5):392-7. Epub 2016 Mar 21.

Department of Hematology and Oncology, University Medical Centre Mannheim, Mannheim, Germany.

Background: Bone marrow (BM) histology/immunohistochemistry, KIT D816V mutation analysis and serum tryptase measurements are mandatory tools for diagnosis of systemic mastocytosis (SM).

Materials And Methods: Within the 'German Registry of Disorders on Eosinophils and Mast Cells', we identified 65 patients with SM who had two consecutive BM biopsies. The first biopsy was evaluated by a local pathologist (LP) and the second biopsy by a reference pathologist (RP) of the 'European Competence Network on Mastocytosis (ECNM)'.

Results: Final diagnoses by RP were SM (n = 27), SM or aggressive SM (ASM) with associated clonal haematological non-mast cell lineage disease [(A)SM-AHNMD, n = 34)] or mast cell leukaemia ± AHNMD (n = 4). In 15 of 65 patients (23%), initial diagnoses by LP were incorrect (by overlooking SM), for example primary myelofibrosis (n = 3), myelodysplastic/myeloproliferative neoplasm unclassified (n = 3) or B-cell lymphoma (n = 2). Fourteen of 15 patients (93%) with incorrect diagnosis had an advanced SM, mostly (A)SM-AHNMD. In the 50 concordantly diagnosed patients, immunohistochemical markers for quantitative assessment of mast cell infiltration, for example CD117 (KIT) or CD25, were applied by LP in only 34 of 50 patients (68%), and mutational analysis for KIT D816V was performed or recommended in only 13 of 50 patients (26%). Finally, the subclassification of SM was discordant because LP did not diagnose AHNMD in nine of 50 (18%) patients.

Conclusions: In summary, adequate diagnosis and subclassification of SM requires an in-depth evaluation of the BM by experienced haematopathologists (preferably in a reference centre) in combination with molecular genetics, serum tryptase level and clinical parameters.
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http://dx.doi.org/10.1111/eci.12607DOI Listing
May 2016

Diagnostic challenges in the work up of hypereosinophilia: pitfalls in bone marrow core biopsy interpretation.

Ann Hematol 2016 Mar 22;95(4):557-62. Epub 2016 Jan 22.

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

The FIP1L1-PDGFRA (FP) fusion gene is identified in a substantial proportion of patients with eosinophilia-associated myeloproliferative neoplasms (MPN-eo) who subsequently achieve rapid and durable remissions on imatinib. In the initial diagnostic work-up of hypereosinophilia (HE), histologic and immunohistochemical evaluation of a bone marrow (BM) core biopsy is considered essential for the differentiation between reactive hypereosinophilia (HER), MPN-eo and hypereosinophilic syndrome (HES). We therefore retrospectively analysed the initial reports of BM core biopsies from 116 patients who were subsequently identified as FP positive (FP+, n = 56) or FP negative/corticosteroid-responsive HER or HES (n = 60). Compared to HER or HES, detection of FP was more frequently associated with increased numbers of blasts (11/56 vs. 2/60, p = 0.007) and mast cells (23/33 vs. 7/23, p = 0.006; with expression of CD25 [11/18 vs. 2/13, p = 0.025]), and/or fibrosis (25/35 vs. 1/23, p < 0.0001). In FP+ patients, HE was correctly associated with an underlying clonal haematologic disorder in only 36/56 (64 %) of cases, but final BM diagnoses included a variety of diagnoses such as MPN-eo (n = 15), acute myeloid leukaemia (n = 8), systemic mastocytosis (n = 6), chronic myeloid leukaemia (n = 5) or unclassified MPN (n = 2). We conclude that the final evaluation of BM core biopsies in the diagnostic work-up of HE should include comprehensive morphologic (stains for myeloid blast cells, mast cells and fibres) and genetic analyses before a final diagnosis is established.
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http://dx.doi.org/10.1007/s00277-016-2598-xDOI Listing
March 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

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

Limited duration of complete remission on ruxolitinib in myeloid neoplasms with PCM1-JAK2 and BCR-JAK2 fusion genes.

Ann Hematol 2015 Feb 27;94(2):233-8. Epub 2014 Sep 27.

III. Medizinische Klinik, Universitätsmedizin Mannheim, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.

Rearrangements of chromosome band 9p24 are known to be associated with JAK2 fusion genes, e.g., t(8;9)(p22;p24) with a PCM1-JAK2 and t(9;22)(p24;q11) with a BCR-JAK2 fusion gene, respectively. In association with myeloid neoplasms, the clinical course is aggressive, and in absence of effective conventional treatment options, long-term remission is usually only observed after allogeneic stem cell transplantation (ASCT). With the discovery of inhibitors of the JAK2 tyrosine kinase and based on encouraging in vitro and in vivo data, we treated two male patients with myeloid neoplasms and a PCM1-JAK2 or a BCR-JAK2 fusion gene, respectively, with the JAK1/JAK2 inhibitor ruxolitinib. After 12 months of treatment, both patients achieved a complete clinical, hematologic, and cytogenetic response. Non-hematologic toxicity was only grade 1 while no hematologic toxicity was observed. However, remission in both patients was only short-term, with relapse occurring after 18 and 24 months, respectively, making ASCT indispensable in both cases. This data highlight (1) the ongoing importance of cytogenetic analysis for the diagnostic work-up of myeloid neoplasms as it may guide targeted therapy and (2) remission under ruxolitinib may only be short-termed in JAK2 fusion genes but it may be an important bridging therapy prior to ASCT.
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http://dx.doi.org/10.1007/s00277-014-2221-yDOI Listing
February 2015

Activity-induced dendrite and dendritic spine development in human amyloid precursor protein transgenic mice.

Int J Dev Neurosci 2011 Apr 26;29(2):107-14. Epub 2011 Jan 26.

Department of Anatomy, Histology and Embryology, Semmelweis University Medical School, Tűzoltó u. 58, H-1450 Budapest, Hungary.

The amyloid precursor protein is essential for proper neuronal function but an imbalance in processing or metabolism or its overexpression lead to severe malfunction of the brain. The present study focused on dendritic morphology of hippocampal neurons in mice overexpressing the wild-type human amyloid precursor protein (hAPP). In addition, we examined whether enhanced physical activity may affect hAPP-related morphological changes. Overexpression of hAPP resulted in significant enlargement of dendrites, especially within the basal dendritic field but had no effect on spine density. Enhanced physical activity only moderately potentiated hAPP induced changes in dendritic size. Physical activity dependent increases in spine density were, however, augmented by hAPP overexpression. The results suggest that enhanced levels of wild-type hAPP do not result in degenerative changes of neuronal morphology, but rather promote dendritic growth.
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http://dx.doi.org/10.1016/j.ijdevneu.2011.01.001DOI Listing
April 2011

Transgenic expression of human wild-type amyloid precursor protein decreases neurogenesis in the adult hippocampus.

Hippocampus 2010 Aug;20(8):971-9

Institute of Biology II, Universität Leipzig, Leipzig, Germany.

Besides its role in Alzheimer's disease, the amyloid precursor protein (APP) is implicated in several physiological functions in neuronal tissue such as cell survival, neurite outgrowth, synaptic formation, and neuronal plasticity. The present study analyzed effects of human wild-type APP (hAPP) overexpression on adult hippocampal neurogenesis in transgenic mice. Mice were housed under either standard or enriched conditions, the latter to boost neurogenetic activity. Different aspects of neurogenesis including proliferation, survival, and differentiation were assessed by employing the BrdU-incorporation method and, in parallel, immunohistochemistry for the neuronal and glial markers NeuN and S100b, respectively. Overexpression of hAPP caused a significant decrease in cell proliferation under standard housing conditions. The relative increase in the proliferation rate following housing in enriched environment was not different to that observed in wild-type mice. Overexpression of hAPP, on the other hand, promoted the survival of newly generated cells, but just under conditions of standard housing. Findings further suggest that overexpression of hAPP suppresses the phenotypic shift toward neuronal differentiation under conditions of enriched environment. In summary, the results reveal a dual effect of APP on adult hippocampal neurogenesis, comprising antiproliferative and prosurvival activities.
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http://dx.doi.org/10.1002/hipo.20693DOI Listing
August 2010

Constitutively enhanced p21Ras activity amplifies dendritic remodeling of hippocampal neurons during physical activity.

Int J Dev Neurosci 2009 Jun 13;27(4):407-11. Epub 2009 Mar 13.

Department of Anatomy, Histology and Embryology, Semmelweis University Medical School, Tuzoltó u. 58, H-1450 Budapest, Hungary.

In the present study we show that overexpression of constitutively active Ras amplifies the dendritic remodeling observed when animals were allowed to be physically active. The monomeric G-protein Ras is a key molecular trigger of distinct signal transduction pathways that play an important role in proper functioning of neurons. Our previous studies on Ras-transgenic synRas mice have demonstrated a considerable impact of Ras on dendritic growth, extension and synaptic connectivity of neurons. Voluntary access to a running wheel resulted in enlargement of hippocampal pyramidal cell dendrites in wild-type mice as expected. However, constitutively elevated Ras activity further enhanced dendritic growth and branching especially of apical arbors. The resultant dendritic surface gain was paralleled by a significant increase in dendritic spine density. Since Ras is crucially involved in signaling and cascades of neurotrophins that are elevated after physical activity, these results strongly suggest an important role of Ras in dendritic dynamics during induced neuronal remodeling.
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http://dx.doi.org/10.1016/j.ijdevneu.2009.03.002DOI Listing
June 2009
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