Publications by authors named "Georgia Metzgeroth"

62 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

Preclinical evaluation of eltrombopag in a PDX model of myelodysplastic syndromes.

Leukemia 2021 Jun 25. Epub 2021 Jun 25.

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

Preclinical research of myelodysplastic syndromes (MDSs) is hampered by a lack of feasible disease models. Previously, we have established a robust patient-derived xenograft (PDX) model for MDS. Here we demonstrate for the first time that this model is applicable as a preclinical platform to address pending clinical questions by interrogating the efficacy and safety of the thrombopoietin receptor agonist eltrombopag. Our preclinical study included n = 49 xenografts generated from n = 9 MDS patient samples. Substance efficacy was evidenced by FACS-based human platelet quantification and clonal bone marrow evolution was reconstructed by serial whole-exome sequencing of the PDX samples. In contrast to clinical trials in humans, this experimental setup allowed vehicle- and replicate-controlled analyses on a patient-individual level deciphering substance-specific effects from natural disease progression. We found that eltrombopag effectively stimulated thrombopoiesis in MDS PDX without adversely affecting the patients' clonal composition. In conclusion, our MDS PDX model is a useful tool for testing new therapeutic concepts in MDS preceding clinical trials.
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http://dx.doi.org/10.1038/s41375-021-01327-wDOI Listing
June 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

Genome-wide DNA methylation analysis pre- and post-lenalidomide treatment in patients with myelodysplastic syndrome with isolated deletion (5q).

Ann Hematol 2021 Jun 27;100(6):1463-1471. Epub 2021 Apr 27.

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

Myelodysplastic syndrome (MDS) with isolated deletion of chromosome 5q (MDS del5q) is a distinct subtype of MDS with quite favorable prognosis and excellent response to treatment with lenalidomide. Still, a relevant percentage of patients do not respond to lenalidomide and even experience progression to acute myeloid leukemia (AML). In this study, we aimed to investigate whether global DNA methylation patterns could predict response to lenalidomide. Genome-wide DNA methylation analysis using Illumina 450k methylation arrays was performed on n=51 patients with MDS del5q who were uniformly treated with lenalidomide in a prospective multicenter trial of the German MDS study group. To study potential direct effects of lenalidomide on DNA methylation, 17 paired samples pre- and post-treatment were analyzed. Our results revealed no relevant effect of lenalidomide on methylation status. Furthermore, methylation patterns prior to therapy could not predict lenalidomide response. However, methylation clustering identified a group of patients with a trend towards inferior overall survival. These patients showed hypermethylation of several interesting target genes, including genes of relevant signaling pathways, potentially indicating the evaluation of novel therapeutic targets.
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http://dx.doi.org/10.1007/s00277-021-04492-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8116243PMC
June 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

High erythroferrone expression in CD71 erythroid progenitors predicts superior survival in myelodysplastic syndromes.

Br J Haematol 2021 03 24;192(5):879-891. Epub 2021 Jan 24.

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

Ineffective erythropoiesis and iron overload are common in myelodysplastic syndromes (MDS). Erythroferrone (ERFE) and growth/differentiation factor 15 (GDF15) are two regulators of iron homeostasis produced by erythroid progenitors. Elevated systemic levels of ERFE and GDF15 in MDS are associated with dysregulated iron metabolism and iron overload, which is especially pronounced in MDS with SF3B1 gene mutations. However, the role of ERFE and GDF15 in MDS pathogenesis and their influence on disease progression are largely unknown. Here, we analyzed the expression of ERFE and GDF15 in CD71 erythroid progenitors of n = 111 MDS patients and assessed their effects on patient survival. The expression of ERFE and GDF15 in MDS was highly aberrant. Unexpectedly, ERFE expression in erythroprogenitors was highly relevant for MDS prognosis and independent of International Prognostic Scoring System (IPSS) stratification. Although ERFE expression was increased in patients with SF3B1 mutations, it predicted overall survival (OS) in both the SF3B1wt and SF3B1mut subgroups. Of note, ERFE overexpression predicted superior OS in the IPSS low/Int-1 subgroup and in patients with normal karyotype. Similar observations were made for GDF15, albeit not reaching statistical significance. In summary, our results revealed a strong association between ERFE expression and MDS outcome, suggesting a possible involvement of ERFE in molecular MDS pathogenesis.
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http://dx.doi.org/10.1111/bjh.17314DOI Listing
March 2021

Replication stress signaling is a therapeutic target in myelodysplastic syndromes with splicing factor mutations.

Haematologica 2020 09 14;Online ahead of print. Epub 2020 Sep 14.

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

Somatic mutations in genes coding for splicing factors, e.g. SF3B1, U2AF1, SRSF2, and others are found in approximately 50% of patients with Myelodysplastic Syndromes (MDS). These mutations have been predicted to frequently occur early in the mutational hierarchy of the disease therefore making them particularly attractive potential therapeutic targets. Recent studies in cell lines engineered to carry splicing factor mutations have revealed a strong association with elevated levels of DNA:RNA intermediates (R-loops) and a dependency on proper ATR function. However, data confirming this hypothesis in a representative cohort of primary MDS patient samples have so far been missing. Using CD34+ cells isolated from MDS patients with and without splicing factor mutations as well as healthy controls we show that splicing factor mutation-associated R-loops lead to elevated levels of replication stress and ATR pathway activation. Moreover, splicing factor mutated CD34+ cells are more susceptible to pharmacological inhibition of ATR resulting in elevated levels of DNA damage, cell cycle blockade, and cell death. This can be enhanced by combination treatment with low-dose splicing modulatory compound Pladienolide B. We further confirm the direct association of R-loops and ATR sensitivity with the presence of a splicing factor mutation using lentiviral overexpression of wild-type and mutant SRSF2 P95H in cord blood CD34+ cells. Collectively, our results from n=53 MDS patients identify replication stress and associated ATR signaling to be critical pathophysiological mechanisms in primary MDS CD34+ cells carrying splicing factor mutations, and provide a preclinical rationale for targeting ATR signaling in these patients.
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http://dx.doi.org/10.3324/haematol.2020.254193DOI Listing
September 2020

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

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

Magnetic resonance imaging reveals distinct bone marrow patterns in indolent and advanced systemic mastocytosis.

Ann Hematol 2019 Dec 5;98(12):2693-2701. Epub 2019 Nov 5.

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

Systemic mastocytosis (SM) is broadly subcategorized according to mast cell (MC) burden and organ involvement into indolent (ISM), smoldering (SSM), and advanced SM (AdvSM). However, the pattern and extent of bone involvement remains controversial. In this institutional review board (IRB)-approved study, 115 patients with different forms of SM (ISM (n = 37, 32%), SSM (n = 9, 8%), and AdvSM (n = 69, 60%)) underwent a whole-body magnetic resonance imaging including sagittal and coronal T1 and turbo inversion recovery magnitude (TIRM) sequences of the spine. The evaluation included the pattern and extent of pathologic bone marrow (BM) signals in the spine and extremities, osteolytic lesions, and vertebral fractures. A pathologic BM pattern was observed in 4/37 (11%), 8/9 (89%), and 66/69 (96%); affection of the appendicular skeleton in 3/37 (8%), 8/9 (89%), and 67/69 (97%); and vertebral fractures in 7/37 (19%), 0/9, and 13/69 (19%) patients with ISM, SSM, and AdvSM, respectively. In AdvSM, pathologic BM pattern included activated (62%), diffuse sclerotic (25%), and small-spotted BM (9%), respectively. Only activated/sclerotic BM was associated with significantly higher MC burden, organ damage, and inferior median survival (2.9 years, p = 0.04). Vertebral fractures resembled classical multi-segmental osteoporotic fractures in ISM but not in AdvSM in which they were only found in activated/sclerotic BM. Only one patient with AdvSM had a focal osteolytic lesion in the femur. Activated/sclerotic BM changes of the spine and affection of the appendicular skeleton are indicative for SSM or AdvSM. Osteolytic lesions, which are very rare, and osteoporotic fractures are ineligible for the diagnosis of AdvSM.
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http://dx.doi.org/10.1007/s00277-019-03826-4DOI Listing
December 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

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

Safety and efficacy of the CD95-ligand inhibitor asunercept in transfusion-dependent patients with low and intermediate risk MDS.

Leuk Res 2018 05 10;68:62-69. Epub 2018 Mar 10.

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

In low risk MDS, increased apoptosis of erythroid progenitors mediated via CD95 (Fas) activation has been described to result in peripheral cytopenia. Blockade of the CD95 system can improve erythropoiesis in MDS. Asunercept (APG101) is a fusion protein consisting of the extracellular domain of human CD95 and the Fc domain of human IgG1 blocking the interaction between CD95 and its ligand. Here we report on results from a phase I study in 20 transfusion-dependent low and intermediate risk MDS patients treated with intravenous asunercept (EudraCT 2012-003027-37). Primary objectives were safety and tolerability as well as pharmacodynamic effects. Secondary objectives were hematologic improvement, incidence and time to leukemic progression as well as overall survival. Frequency and severity of adverse events were in range of what could be expected in a patient cohort comprising of elderly MDS patients. Two patients experienced a serious adverse event with a suspected relationship to asunercept. The incidence of disease progression was low. In the 20 patients a decrease of the transfusion need from a mean of 10,8 (±5,1) pRBCs during the 12 weeks treatment phase to a mean of 10,0 (±4,2) pRBCs at the end of the study was observed. In conclusion, asunercept was well tolerated and showed efficacy in transfusion-dependent low and intermediate risk MDS patients. Further clinical investigation is warranted, particularly in combination with erythropoiesis stimulating agents (ESAs).
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http://dx.doi.org/10.1016/j.leukres.2018.03.007DOI Listing
May 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

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

Concomitant MDS with isolated 5q deletion and MGUS: case report and review of molecular aspects.

Eur J Haematol 2017 Mar 27;98(3):302-310. Epub 2016 Dec 27.

Medical faculty Mannheim of the University of Heidelberg, Mannheim, Germany.

Patients with monoclonal gammopathy of undetermined significance (MGUS) have a higher risk for the development of concomitant primary cancers such as multiple myeloma (MM) and myelodysplastic syndrome (MDS). We report the case of patient initially suffering from MGUS of the IgG lambda subtype for more than 10 yr, which evolved to MM and MDS with deletion (5q) with severe pancytopenia. Due to pancytopenia, he received dose-reduced treatment with lenalidomide and dexamethasone. He achieved an ongoing transfusion independency after about 1 month of treatment. Bone marrow taken 14 months after start of treatment showed a complete cytogenetic response of the del(5q) clone and a plasma cell infiltration below 5%. In contrast to the development of MM in MGUS patients, the subsequent occurrence of MDS after diagnosis of MGUS is infrequent. Moreover, the biological association of MDS with MGUS is not sufficiently understood, but the non-treatment-related occurrence supports the pathogenetic role of pre-existing alterations of stem cells. Here, we summarize data on concomitant MDS and MGUS/MM with particular emphasis on molecular aspects.
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http://dx.doi.org/10.1111/ejh.12827DOI Listing
March 2017

Mutational hierarchies in myelodysplastic syndromes dynamically adapt and evolve upon therapy response and failure.

Blood 2016 09 6;128(9):1246-59. Epub 2016 Jun 6.

Department of Hematology and Oncology.

Clonal evolution is believed to be a main driver for progression of various types of cancer and implicated in facilitating resistance to drugs. However, the hierarchical organization of malignant clones in the hematopoiesis of myelodysplastic syndromes (MDS) and its impact on response to drug therapy remain poorly understood. Using high-throughput sequencing of patient and xenografted cells, we evaluated the intratumoral heterogeneity (n= 54) and reconstructed mutational trajectories (n = 39) in patients suffering from MDS (n = 52) and chronic myelomonocytic leukemia-1 (n = 2). We identified linear and also branching evolution paths and confirmed on a patient-specific level that somatic mutations in epigenetic regulators and RNA splicing genes frequently constitute isolated disease-initiating events. Using high-throughput exome- and/or deep-sequencing, we analyzed 103 chronologically acquired samples from 22 patients covering a cumulative observation time of 75 years MDS disease progression. Our data revealed highly dynamic shaping of complex oligoclonal architectures, specifically upon treatment with lenalidomide and other drugs. Despite initial clinical response to treatment, patients' marrow persistently remained clonal with rapid outgrowth of founder-, sub-, or even fully independent clones, indicating an increased dynamic rate of clonal turnover. The emergence and disappearance of specific clones frequently correlated with changes of clinical parameters, highlighting their distinct and far-reaching functional properties. Intriguingly, increasingly complex mutational trajectories are frequently accompanied by clinical progression during the course of disease. These data substantiate a need for regular broad molecular monitoring to guide clinical treatment decisions in MDS.
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http://dx.doi.org/10.1182/blood-2015-11-679167DOI Listing
September 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

Identification and functional characterization of imatinib-sensitive DTD1-PDGFRB and CCDC88C-PDGFRB fusion genes in eosinophilia-associated myeloid/lymphoid neoplasms.

Genes Chromosomes Cancer 2014 May;53(5):411-21

Eosinophilia-associated myeloid neoplasms with rearrangement of chromosome bands 5q31-33 are frequently associated with PDGFRB fusion genes, which are exquisitely sensitive to treatment with imatinib. In search for novel fusion partners of PDGFRB, we analyzed three cases with translocation t(5;20)(q33;p11), t(5;14)(q33;q32), and t(5;17;14)(q33;q11;q32) by 5′-rapid amplification of cDNA ends polymerase chain reaction (5′-RACE-PCR) and DNA-based long-distance inverse PCR (LDI-PCR) with primers derived from PDGFRB. LDI-PCR revealed a fusion between CCDC88C exon 25 and PDGFRB exon 11 in the case with t(5;17;14)(q33;q11;q32) while 5′-RACE-PCR identified fusions between CCDC88C exon 10 and PDGFRB exon 12 and between DTD1 exon 4 and PDGFRB exon 12 in the cases with t(5;14)(q33;q32) and t(5;20)(q33;p11), respectively. The PDGFRB tyrosine-kinase domain is predicted to be retained in all three fusion proteins. The partner proteins contained coiled-coil domains or other domains, which putatively lead to constitutive activation of the PDGFRB fusion protein. In vitro functional analyses confirmed transforming activity and imatinib-sensitivity of the fusion proteins. All three patients achieved rapid and durable complete hematologic remissions on imatinib.
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http://dx.doi.org/10.1002/gcc.22153DOI Listing
May 2014

Myelodysplastic cells in patients reprogram mesenchymal stromal cells to establish a transplantable stem cell niche disease unit.

Cell Stem Cell 2014 Jun 3;14(6):824-37. Epub 2014 Apr 3.

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

Myelodysplastic syndromes (MDSs) are a heterogeneous group of myeloid neoplasms with defects in hematopoietic stem and progenitor cells (HSPCs) and possibly the HSPC niche. Here, we show that patient-derived mesenchymal stromal cells (MDS MSCs) display a disturbed differentiation program and are essential for the propagation of MDS-initiating Lin(-)CD34(+)CD38(-) stem cells in orthotopic xenografts. Overproduction of niche factors such as CDH2 (N-Cadherin), IGFBP2, VEGFA, and LIF is associated with the ability of MDS MSCs to enhance MDS expansion. These factors represent putative therapeutic targets in order to disrupt critical hematopoietic-stromal interactions in MDS. Finally, healthy MSCs adopt MDS MSC-like molecular features when exposed to hematopoietic MDS cells, indicative of an instructive remodeling of the microenvironment. Therefore, this patient-derived xenograft model provides functional and molecular evidence that MDS is a complex disease that involves both the hematopoietic and stromal compartments. The resulting deregulated expression of niche factors may well also be a feature of other hematopoietic malignancies.
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http://dx.doi.org/10.1016/j.stem.2014.02.014DOI Listing
June 2014
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