Publications by authors named "Gregor Hoermann"

85 Publications

Precision Medicine in Hematology 2021: Definitions, Tools, Perspectives, and Open Questions.

Hemasphere 2021 Mar 17;5(3):e536. Epub 2021 Feb 17.

Department of Medicine I, Division of Hematology & Hemostaseology, Medical University of Vienna, Austria.

During the past few years, our understanding of molecular mechanisms and cellular interactions relevant to malignant blood cell disorders has improved substantially. New insights include a detailed knowledge about disease-initiating exogenous factors, endogenous (genetic, somatic, epigenetic) elicitors or facilitators of disease evolution, and drug actions and interactions that underlie efficacy and adverse event profiles in defined cohorts of patients. As a result, precision medicine and personalized medicine are rapidly growing new disciplines that support the clinician in making the correct diagnosis, in predicting outcomes, and in optimally selecting patients for interventional therapies. In addition, precision medicine tools are greatly facilitating the development of new drugs, therapeutic approaches, and new multiparametric prognostic scoring models. However, although the emerging roles of precision medicine and personalized medicine in hematology and oncology are clearly visible, several questions remain. For example, it remains unknown how precision medicine tools can be implemented in healthcare systems and whether all possible approaches are also affordable. In addition, there is a need to define terminologies and to relate these to specific and context-related tools and strategies in basic and applied science. To discuss these issues, a working conference was organized in September 2019. The outcomes of this conference are summarized herein and include a proposal for definitions, terminologies, and applications of precision and personalized medicine concepts and tools in hematologic neoplasms. We also provide proposals aimed at reducing costs, thereby making these applications affordable in daily practice.
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http://dx.doi.org/10.1097/HS9.0000000000000536DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7892291PMC
March 2021

Evaluation of four commercial, fully automated SARS-CoV-2 antibody tests suggests a revision of the Siemens SARS-CoV-2 IgG assay.

Clin Chem Lab Med 2021 Jan 14. Epub 2021 Jan 14.

Central Institute of Clinical and Chemical Laboratory Diagnostics, University Hospital of Innsbruck, Innsbruck, Austria.

Objectives: Serological tests detect antibodies against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in the ongoing coronavirus disease-19 (COVID-19) pandemic. Independent external clinical validation of performance characteristics is of paramount importance.

Methods: Four fully automated assays, Roche Elecsys Anti-SARS-CoV-2, Abbott SARS-CoV-2 IgG, Siemens SARS-CoV-2 total (COV2T) and SARS-CoV-2 IgG (COV2G) were evaluated using 350 pre-pandemic samples and 700 samples from 245 COVID-19 patients (158 hospitalized, 87 outpatients).

Results: All tests showed very high diagnostic specificity. Sensitivities in samples collected at least 14 days after disease onset were slightly lower than manufacturers' claims for Roche (93.0%), Abbott (90.8%), and Siemens COV2T (90.3%), and distinctly lower for Siemens COV2G (78.8%). Concordantly negative results were enriched for immunocompromised patients. ROC curve analyses suggest a lowering of the cut-off index for the Siemens COV2G assay. Finally, the combination of two anti-SARS-CoV-2 antibody assays is feasible when considering borderline reactive results.

Conclusions: Thorough on-site evaluation of commercially available serologic tests for detection of antibodies against SARS-CoV-2 remains imperative for laboratories. The potentially impaired sensitivity of the Siemens COV2G necessitates a switch to the company's newly filed SARS-CoV-2 IgG assay for follow-up studies. A combination of tests could be considered in clinical practice.
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http://dx.doi.org/10.1515/cclm-2020-1758DOI Listing
January 2021

Myelomonocytic skewing in chronic myelomonocytic leukemia: phenotypic, molecular and biologic features and impact on survival.

Eur J Haematol 2021 Jan 12. Epub 2021 Jan 12.

Ludwig Boltzmann Institute for Hematology and Oncology (LBI HO), Medical University of Vienna, Vienna, Austria.

Background: Myelomonocytic skewing is considered as a key pathophysiologic phenomenon in chronic myelomonocytic leukemia (CMML) but its prevalence and potential correlation with phenotypic, genotypic and clinical features is poorly defined.

Methods: Skewed differentiation toward the myelomonocytic over erythroid commitment as indicated by an inverse ratio of myelomonocytic/erythroid colonies was investigated in 146 patients with CMML by semisolid in vitro cultures.

Results: There was a high prevalence of myelomonocytic skewing in CMML patients (120/146, 82%) whereas this phenomenon was rare in normal individuals (1/98, 1%). CMML patients with myelomonocytic skewing had higher white blood cell and peripheral blast cell counts, and lower platelet values. The number of mutations in genes of the epigenetic and/or splicing category was higher in CMML patients with as compared to patients without skewing. Patients with myelomonocytic skewing had more frequently mutations in RASopathy genes and higher growth factor independent myeloid colony formation. Interestingly, the lack of myelomonocytic skewing discriminated CMML patients with a particularly favorable prognosis (60 vs 19 months, p=0.003) and a minimal risk of transformation.

Conclusion: Myelomonocytic skewing as determined by semisolid cultures can discriminate subgroups of CMML patients with a different phenotype, a different genotype and a different prognosis.
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http://dx.doi.org/10.1111/ejh.13577DOI Listing
January 2021

Clinical Impact of Inherited and Acquired Genetic Variants in Mastocytosis.

Int J Mol Sci 2021 Jan 2;22(1). Epub 2021 Jan 2.

Ludwig Boltzmann Institute for Hematology and Oncology, Medical University of Vienna, 1090 Vienna, Austria.

Mastocytosis is a rare and complex disease characterized by expansion of clonal mast cells (MC) in skin and/or various internal organ systems. Involvement of internal organs leads to the diagnosis of systemic mastocytosis (SM). The WHO classification divides SM into indolent SM, smoldering SM and advanced SM variants, including SM with an associated hematologic neoplasm, aggressive SM, and MC leukemia. Historically, genetic analysis of individuals with pure cutaneous mastocytosis (CM) and SM have focused primarily on cohort studies of inherited single nucleotide variants and acquired pathogenic variants. The most prevalent pathogenic variant (mutation) in patients with SM is p.D816V, which is detectable in most adult patients. Other somatic mutations have also been identified-especially in advanced SM-in , , , , and , and shown to impact clinical and cellular phenotypes. Although only small patient cohorts have been analyzed, disease associations have also been identified in several germline variants within genes encoding certain cytokines or their receptors (, , , , ) and toll-like receptors. More recently, an increased prevalence of hereditary alpha-tryptasemia (HαT) caused by increased copy number encoding alpha-tryptase has been described in patients with SM. Whereas HαT is found in 3-6% of general Western populations, it is identified in up to 17% of patients with SM. In the current manuscript we review the prevalence, functional role and clinical impact of various germline and somatic genetic variants in patients with mastocytosis.
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http://dx.doi.org/10.3390/ijms22010411DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7795405PMC
January 2021

Cardiopulmonary recovery after COVID-19 - an observational prospective multi-center trial.

Eur Respir J 2020 Dec 10. Epub 2020 Dec 10.

Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria.

Background: After the 2002/2003 SARS outbreak, 30% of survivors exhibited persisting structural pulmonary abnormalities. The long-term pulmonary sequelae of coronavirus disease 2019 (COVID-19) are yet unknown, and comprehensive clinical follow-up data are lacking.

Methods: In this prospective, multicentre, observational study, we systematically evaluated the cardiopulmonary damage in subjects recovering from COVID-19 at 60 and 100 days after confirmed diagnosis. We conducted a detailed questionnaire, clinical examination, laboratory testing, lung function analysis, echocardiography, and thoracic low-dose computed tomography (CT).

Results: Data from 145 COVID-19 patients were evaluated, and 41% of all subjects exhibited persistent symptoms 100 days after COVID-19 onset, with dyspnea being most frequent (36%). Accordingly, patients still displayed an impaired lung function, with a reduced diffusing capacity in 21% of the cohort being the most prominent finding. Cardiac impairment, including a reduced left ventricular function or signs of pulmonary hypertension, was only present in a minority of subjects. CT scans unveiled persisting lung pathologies in 63% of patients, mainly consisting of bilateral ground-glass opacities and/or reticulation in the lower lung lobes, without radiological signs of pulmonary fibrosis. Sequential follow-up evaluations at 60 and 100 days after COVID-19 onset demonstrated a vast improvement of both, symptoms and CT abnormalities over time.

Conclusion: A relevant percentage of post-COVID-19 patients presented with persisting symptoms and lung function impairment along with pulmonary abnormalities more than 100 days after the diagnosis of COVID-19. However, our results indicate a significant improvement in symptoms and cardiopulmonary status over time.
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http://dx.doi.org/10.1183/13993003.03481-2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7736754PMC
December 2020

Delineation of target expression profiles in CD34+/CD38- and CD34+/CD38+ stem and progenitor cells in AML and CML.

Blood Adv 2020 Oct;4(20):5118-5132

Ludwig Boltzmann Institute for Hematology and Oncology.

In an attempt to identify novel markers and immunological targets in leukemic stem cells (LSCs) in acute myeloid leukemia (AML) and chronic myeloid leukemia (CML), we screened bone marrow (BM) samples from patients with AML (n = 274) or CML (n = 97) and controls (n = 288) for expression of cell membrane antigens on CD34+/CD38- and CD34+/CD38+ cells by multicolor flow cytometry. In addition, we established messenger RNA expression profiles in purified sorted CD34+/CD38- and CD34+/CD38+ cells using gene array and quantitative polymerase chain reaction. Aberrantly expressed markers were identified in all cohorts. In CML, CD34+/CD38- LSCs exhibited an almost invariable aberration profile, defined as CD25+/CD26+/CD56+/CD93+/IL-1RAP+. By contrast, in patients with AML, CD34+/CD38- cells variably expressed "aberrant" membrane antigens, including CD25 (48%), CD96 (40%), CD371 (CLL-1; 68%), and IL-1RAP (65%). With the exception of a subgroup of FLT3 internal tandem duplication-mutated patients, AML LSCs did not exhibit CD26. All other surface markers and target antigens detected on AML and/or CML LSCs, including CD33, CD44, CD47, CD52, CD105, CD114, CD117, CD133, CD135, CD184, and roundabout-4, were also found on normal BM stem cells. However, several of these surface targets, including CD25, CD33, and CD123, were expressed at higher levels on CD34+/CD38- LSCs compared with normal BM stem cells. Moreover, antibody-mediated immunological targeting through CD33 or CD52 resulted in LSC depletion in vitro and a substantially reduced LSC engraftment in NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mice. Together, we have established surface marker and target expression profiles of AML LSCs and CML LSCs, which should facilitate LSC enrichment, diagnostic LSC phenotyping, and development of LSC-eradicating immunotherapies.
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http://dx.doi.org/10.1182/bloodadvances.2020001742DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7594398PMC
October 2020

Thyroid and androgen receptor signaling are antagonized by μ-Crystallin in prostate cancer.

Int J Cancer 2021 Feb 31;148(3):731-747. Epub 2020 Oct 31.

Department of Pathology, Medical University Vienna, Vienna, Austria.

Androgen deprivation therapy (ADT) remains a key approach in the treatment of prostate cancer (PCa). However, PCa inevitably relapses and becomes ADT resistant. Besides androgens, there is evidence that thyroid hormone thyroxine (T4) and its active form 3,5,3'-triiodo-L-thyronine (T3) are involved in the progression of PCa. Epidemiologic evidences show a higher incidence of PCa in men with elevated thyroid hormone levels. The thyroid hormone binding protein μ-Crystallin (CRYM) mediates intracellular thyroid hormone action by sequestering T3 and blocks its binding to cognate receptors (TRα/TRβ) in target tissues. We show in our study that low CRYM expression levels in PCa patients are associated with early biochemical recurrence and poor prognosis. Moreover, we found a disease stage-specific expression of CRYM in PCa. CRYM counteracted thyroid and androgen signaling and blocked intracellular choline uptake. CRYM inversely correlated with [18F]fluoromethylcholine (FMC) levels in positron emission tomography/magnetic resonance imaging of PCa patients. Our data suggest CRYM as a novel antagonist of T3- and androgen-mediated signaling in PCa. The role of CRYM could therefore be an essential control mechanism for the prevention of aggressive PCa growth.
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http://dx.doi.org/10.1002/ijc.33332DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7756625PMC
February 2021

Impact of Vitamin D Deficiency on COVID-19-A Prospective Analysis from the CovILD Registry.

Nutrients 2020 Sep 11;12(9). Epub 2020 Sep 11.

Department of Internal Medicine II, Infectious Diseases, Pneumology, Rheumatology, Medical University of Innsbruck, 6020 Innsbruck, Austria.

The novel Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is a global health concern. Vitamin D (VITD) deficiency has been suggested to alter SARS-CoV-2 susceptibility and the course of disease. Thus, we aimed to investigate associations of VITD status to disease presentation within the CovILD registry. This prospective, multicenter, observational study on long-term sequelae includes patients with COVID-19 after hospitalization or outpatients with persistent symptoms. Eight weeks after PCR confirmed diagnosis, a detailed questionnaire, a clinical examination, and laboratory testing, including VITD status, were evaluated. Furthermore, available laboratory specimens close to hospital admission were used to retrospectively analyze 25-hydroxyvitamin D levels at disease onset. A total of 109 patients were included in the analysis (60% males, 40% females), aged 58 ± 14 years. Eight weeks after the onset of COVID-19, a high proportion of patients presented with impaired VITD metabolism and elevated parathyroid hormone (PTH) levels. PTH concentrations were increased in patients who needed intensive care unit (ICU) treatment, while VITD levels were not significantly different between disease severity groups. Low VITD levels at disease onset or at eight-week follow-up were not related to persistent symptom burden, lung function impairment, ongoing inflammation, or more severe CT abnormalities. VITD deficiency is frequent among COVID-19 patients but not associated with disease outcomes. However, individuals with severe disease display a disturbed parathyroid-vitamin-D axis within their recovery phase. The proposed significance of VITD supplementation in the clinical management of COVID-19 remains elusive.
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http://dx.doi.org/10.3390/nu12092775DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7551662PMC
September 2020

Clonal Hematopoiesis of Indeterminate Potential: A Multidisciplinary Challenge in Personalized Hematology.

J Pers Med 2020 Aug 20;10(3). Epub 2020 Aug 20.

Ludwig Boltzmann Institute for Hematology and Oncology, Medical University of Vienna, 1090 Vienna, Austria.

Clonal hematopoiesis of indeterminate potential (CHIP) is a common age-related condition that represents a potential pre-phase of hematologic neoplasm. Next-generation sequencing (NGS) is used to detect and monitor clonal hematopoiesis, and the spectrum of mutations substantially overlaps with that of myeloid neoplasms with , , , and being the most frequently mutated. While, in general, the risk of progression to an overt myeloid neoplasm is only modest, the progression risk increases in patients with unexplained cytopenia or multiple mutations. In addition, CHIP represents a previously unrecognized major risk factor for atherosclerosis and cardiovascular disease (CVD), including coronary heart disease, degenerative aortic valve stenosis, and chronic heart failure; and a causative role of CHIP in the development of CVD has been demonstrated in vitro and in vivo. The management of patients with CHIP is a rapidly emerging topic in personalized medicine, as NGS has become widely available for clinical medicine. It requires a highly multidisciplinary setting, including hematology/oncology, cardiology, (clinical) pathology, and genetics for individualized guidance. Further research is urgently needed to provide robust evidence for future guidelines and recommendations on the management of patients with CHIP in the era of personalized medicine.
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http://dx.doi.org/10.3390/jpm10030094DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564336PMC
August 2020

Hereditary α tryptasemia is a valid genetic biomarker for severe mediator-related symptoms in mastocytosis.

Blood 2021 Jan;137(2):238-247

Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria.

Mastocytosis is a hematopoietic neoplasm characterized by expansion of KIT D816V-mutated clonal mast cells in various organs and severe or even life-threatening anaphylactic reactions. Recently, hereditary α-tryptasemia (HαT) has been described as a common genetic trait with increased copy numbers of the α-tryptase encoding gene, TPSAB1, and associated with an increased basal serum tryptase level and a risk of mast cell activation. The purpose of our study was to elucidate the clinical relevance of HαT in patients with mastocytosis. TPSAB1 germline copy number variants were assessed by digital polymerase chain reaction in 180 mastocytosis patients, 180 sex-matched control subjects, 720 patients with other myeloid neoplasms, and 61 additional mastocytosis patients of an independent validation cohort. α-Tryptase encoding TPSAB1 copy number gains, compatible with HαT, were identified in 17.2% of mastocytosis patients and 4.4% of the control population (P < .001). Patients with HαT exhibited higher tryptase levels than patients without HαT (median tryptase in HαT+ cases: 49.6 ng/mL vs HαT- cases: 34.5 ng/mL, P = .004) independent of the mast cell burden. Hymenoptera venom hypersensitivity reactions and severe cardiovascular mediator-related symptoms/anaphylaxis were by far more frequently observed in mastocytosis patients with HαT than in those without HαT. Results were confirmed in an independent validation cohort. The high prevalence of HαT in mastocytosis hints at a potential pathogenic role of germline α-tryptase encoding TPSAB1 copy number gains in disease evolution. Together, our data suggest that HαT is a novel emerging robust biomarker in mastocytosis that is useful for determining the individual patient´s risk of developing severe anaphylaxis.
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http://dx.doi.org/10.1182/blood.2020006157DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7116780PMC
January 2021

Clinical, Hematologic, Biologic and Molecular Characteristics of Patients with Myeloproliferative Neoplasms and a Chronic Myelomonocytic Leukemia-Like Phenotype.

Cancers (Basel) 2020 Jul 14;12(7). Epub 2020 Jul 14.

Department of Internal Medicine V with Hematology, Oncology and Palliative Care, Hospital Hietzing, 1130 Vienna, Austria.

Patients with a myeloproliferative neoplasm (MPN) sometimes show a chronic myelomonocytic leukemia (CMML)-like phenotype but, according to the 2016 WHO classification, a documented history of an MPN excludes the diagnosis of CMML. Forty-one patients with an MPN (35 polycythemia vera (PV), 5 primary myelofibrosis, 1 essential thrombocythemia) and a CMML-like phenotype (MPN/CMML) were comprehensively characterized regarding clinical, hematologic, biologic and molecular features. The white blood cell counts in MPN/CMML patients were not different from CMML patients and PV patients. The hemoglobin values and platelet counts of these patients were higher than in CMML but lower than in PV, respectively. MPN/CMML patients showed myelomonocytic skewing, a typical in vitro feature of CMML but not of PV. The mutational landscape of MPN/CMML was not different from -mutated CMML. In two MPN/CMML patients, development of a CMML-like phenotype was associated with a decrease in the V617F allelic burden. Finally, the prognosis of MPN/CMML (median overall survival (OS) 27 months) was more similar to CMML (-mutated, 28 months; -nonmutated 29 months) than to PV (186 months). In conclusion, we show that patients with MPN and a CMML-like phenotype share more characteristics with CMML than with PV, which may be relevant for their classification and clinical management.
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http://dx.doi.org/10.3390/cancers12071891DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7409251PMC
July 2020

Microarray-Based Detection of Allergen-Reactive IgE in Patients with Mastocytosis.

J Allergy Clin Immunol Pract 2020 Sep 26;8(8):2761-2768.e16. Epub 2020 Apr 26.

Department of Internal Medicine I, Division of Hematology & Hemostaseology, Medical University of Vienna, Vienna, Austria; Ludwig Boltzmann Institute for Hematology and Oncology, Medical University of Vienna, Vienna, Austria. Electronic address:

Background: Because of a high risk to develop fatal anaphylaxis, early detection of immunoglobulin E (IgE)-dependent allergy is of particular importance in patients with mastocytosis.

Objective: We examined whether microarray-based screening for allergen-reactive IgE (allergen-chip) is a sensitive and robust approach to detect specific IgE in patients with mastocytosis.

Methods: Sera for 42 patients were analyzed, including 4 with cutaneous mastocytosis, 2 with mastocytosis in the skin, and 36 with systemic mastocytosis. In addition, sera from an age- and sex-matched control cohort (n = 42) were analyzed.

Results: In 15 of 42 patients with mastocytosis (35.7%), specific IgE was detected by allergen-chip profiling. Ves v 5 and Bet v 1 were the most frequently detected allergens (Ves v 5: 16.7% of patients; Bet v 1: 11.9% of patients). Allergen reactivity was confirmed by demonstrating upregulation of CD203c on blood basophils upon exposure to the respective allergen(s) in these patients. Specific IgE was identified by chip studies in 11 of 26 patients with mastocytosis with mediator-related symptoms (42.3%) and in 4 of 14 patients with mastocytosis without symptoms (28.6%). In the cohort with known allergy, 9 of 9 patients (100%) had a positive allergen-chip result. In patients with mastocytosis without a known allergy (n = 31), the chip identified 6 positive cases (19.5%). The prevalence of chip-positive patients was slightly lower in the mastocytosis group (35.7%) compared with age- and sex-matched controls (40.5%).

Conclusions: Although specific IgE may not be detectable in all sensitized patients with mastocytosis, allergy chip-profiling is a reliable screening approach for the identification of patients with mastocytosis suffering from IgE-dependent allergies.
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http://dx.doi.org/10.1016/j.jaip.2020.04.030DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7116130PMC
September 2020

CDK6 is an essential direct target of NUP98 fusion proteins in acute myeloid leukemia.

Blood 2020 07;136(4):387-400

Institute for Medical Biochemistry, University of Veterinary Medicine Vienna, Vienna, Austria.

Fusion proteins involving Nucleoporin 98 (NUP98) are recurrently found in acute myeloid leukemia (AML) and are associated with poor prognosis. Lack of mechanistic insight into NUP98-fusion-dependent oncogenic transformation has so far precluded the development of rational targeted therapies. We reasoned that different NUP98-fusion proteins deregulate a common set of transcriptional targets that might be exploitable for therapy. To decipher transcriptional programs controlled by diverse NUP98-fusion proteins, we developed mouse models for regulatable expression of NUP98/NSD1, NUP98/JARID1A, and NUP98/DDX10. By integrating chromatin occupancy profiles of NUP98-fusion proteins with transcriptome profiling upon acute fusion protein inactivation in vivo, we defined the core set of direct transcriptional targets of NUP98-fusion proteins. Among those, CDK6 was highly expressed in murine and human AML samples. Loss of CDK6 severely attenuated NUP98-fusion-driven leukemogenesis, and NUP98-fusion AML was sensitive to pharmacologic CDK6 inhibition in vitro and in vivo. These findings identify CDK6 as a conserved, critical direct target of NUP98-fusion proteins, proposing CDK4/CDK6 inhibitors as a new rational treatment option for AML patients with NUP98-fusions.
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http://dx.doi.org/10.1182/blood.2019003267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115844PMC
July 2020

STAT5 is Expressed in CD34/CD38 Stem Cells and Serves as a Potential Molecular Target in Ph-Negative Myeloproliferative Neoplasms.

Cancers (Basel) 2020 Apr 21;12(4). Epub 2020 Apr 21.

Ludwig Boltzmann Institute for Hematology and Oncology, Medical University of Vienna, 1090 Vienna, Austria.

Janus kinase 2 (JAK2) and signal transducer and activator of transcription-5 (STAT5) play a key role in the pathogenesis of myeloproliferative neoplasms (MPN). In most patients, V617F or mutations are found and lead to activation of various downstream signaling cascades and molecules, including STAT5. We examined the presence and distribution of phosphorylated (p) STAT5 in neoplastic cells in patients with MPN, including polycythemia vera (PV, = 10), essential thrombocythemia (ET, = 15) and primary myelofibrosis (PMF, = 9), and in the V617F-positive cell lines HEL and SET-2. As assessed by immunohistochemistry, MPN cells displayed pSTAT5 in all patients examined. Phosphorylated STAT5 was also detected in putative CD34/CD38 MPN stem cells (MPN-SC) by flow cytometry. Immunostaining experiments and Western blotting demonstrated pSTAT5 expression in both the cytoplasmic and nuclear compartment of MPN cells. Confirming previous studies, we also found that JAK2-targeting drugs counteract the expression of pSTAT5 and growth in HEL and SET-2 cells. Growth-inhibition of MPN cells was also induced by the STAT5-targeting drugs piceatannol, pimozide, AC-3-019 and AC-4-130. Together, we show that CD34/CD38 MPN-SC express pSTAT5 and that pSTAT5 is expressed in the nuclear and cytoplasmic compartment of MPN cells. Whether direct targeting of pSTAT5 in MPN-SC is efficacious in MPN patients remains unknown.
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http://dx.doi.org/10.3390/cancers12041021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7225958PMC
April 2020

A genome-wide association study identifies key modulators of complement factor H binding to malondialdehyde-epitopes.

Proc Natl Acad Sci U S A 2020 05 22;117(18):9942-9951. Epub 2020 Apr 22.

Department of Laboratory Medicine, Medical University of Vienna, 1090 Vienna, Austria;

Genetic variants within complement factor H (CFH), a major alternative complement pathway regulator, are associated with the development of age-related macular degeneration (AMD) and other complementopathies. This is explained with the reduced binding of CFH or its splice variant factor H-like protein 1 (FHL-1) to self-ligands or altered self-ligands (e.g., malondialdehyde [MDA]-modified molecules) involved in homeostasis, thereby causing impaired complement regulation. Considering the critical role of CFH in inhibiting alternative pathway activation on MDA-modified surfaces, we performed an unbiased genome-wide search for genetic variants that modify the ability of plasma CFH to bind MDA in 1,830 individuals and characterized the mechanistic basis and the functional consequences of this. In a cohort of healthy individuals, we identified rs1061170 in and the deletion of and as dominant genetic variants that modify CFH/FHL-1 binding to MDA. We further demonstrated that FHR1 and FHR3 compete with CFH for binding to MDA-epitopes and that FHR1 displays the highest affinity toward MDA-epitopes compared to CFH and FHR3. Moreover, FHR1 bound to MDA-rich areas on necrotic cells and prevented CFH from mediating its cofactor activity on MDA-modified surfaces, resulting in enhanced complement activation. These findings provide a mechanistic explanation as to why the deletion of and is protective in AMD and highlight the importance of genetic variants within the locus in the recognition of altered-self in tissue homeostasis.
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http://dx.doi.org/10.1073/pnas.1913970117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7211993PMC
May 2020

A Multidisciplinary Intervention in Childhood Obesity Acutely Improves Insulin Resistance and Inflammatory Markers Independent From Body Composition.

Front Pediatr 2020 21;8:52. Epub 2020 Feb 21.

Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria.

Childhood obesity is an increasing health care problem associated with insulin resistance and low-level systemic inflammation, which can ultimately lead to diabetes. Evidence for efficacy of therapeutic intervention programs on the early development of obesity associated sequelae is moderate. This paper investigates the effect of a multidisciplinary short-term intervention program on insulin resistance and metaflammation in childhood obesity. Two hundred and 36 overweight or obese children and adolescents between the ages of 10 and 14 were included in a prospective 5 months intervention study, which included sports, psychotherapy, and nutritional counseling. Primary endpoints were the effects on body mass index standard deviation score (BMI-SDS) and homeostatic model assessment of insulin resistance (HOMA-IR), key secondary endpoints were the levels of C-reactive protein (CRP), leptin, and adiponectin. At baseline, a substantial proportion of participants showed signs of insulin resistance (mean HOMA-IR 5.5 ± 3.4) despite not meeting the diagnostic criteria for diabetes, and low-level inflammation (mean CRP 3.9 mg/l ± 3.8 mg/l). One hundred and 95 participants (83%) completed the program resulting in a significant reduction in BMI-SDS, HOMA-IR, CRP, and leptin and a significant increase in adiponectin (mean change compared to baseline -0.14, -0.85, -1.0 mg/l, -2.8 ng/ml, and 0.5 μg/ml, respectively; < 0.001 each). Effects on BMI-SDS, HOMA-IR, CRP, and adiponectin were largely independent whereas leptin was positively correlated with BMI-SDS and total fat mass before and after intervention ( = 0.56 and 0.61, < 0.001 each). Short-term multidisciplinary intervention successfully improved body composition, insulin sensitivity, low-level systemic inflammation, and the adipokine profile in childhood obesity. Our findings highlight the immediate connection between obesity and the pathophysiology of its sequelae, and emphasize the importance of early intervention. Continued lifestyle modification is likely necessary to consolidate and augment the long-term effects.
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http://dx.doi.org/10.3389/fped.2020.00052DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7047334PMC
February 2020

Comparison of BCR-ABL1 quantification in peripheral blood and bone marrow using an International Scale-standardized assay for assessment of deep molecular response in chronic myeloid leukemia.

Clin Chem Lab Med 2020 Jul;58(8):1214-1222

Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria.

Background Monitoring of molecular response (MR) using quantitative polymerase chain reaction (PCR) for BCR-ABL1 is a pivotal tool for guiding tyrosine kinase inhibitor therapy and the long-term follow-up of patients with chronic myeloid leukemia (CML). Results of MR monitoring are standardized according to the International Scale (IS), and specific time-dependent molecular milestones for definition of optimal response and treatment failure have been included in treatment recommendations. The common practice to use peripheral blood (PB) instead of bone marrow (BM) aspirate to monitor the MR monitoring in CML has been questioned. Some studies described differences between BCR-ABL1 levels in paired PB and BM specimens. Methods We examined 631 paired PB and BM samples from 283 CML patients in a retrospective single-center study using an IS normalized quantitative reverse transcription (qRT)-PCR assay for quantification of BCR-ABL1IS. Results A good overall concordance of BCR-ABL1IS results was found, a systematic tendency towards higher BCR-ABL1IS levels in PB was observed in samples of CML patients in a major MR. This difference was most pronounced in patients treated with imatinib for at least 1 year. Importantly, the difference resulted in a significantly lower rate of deep MR when BCR-ABL1IS was assessed in the PB compared to BM aspirates. Conclusions In summary, our data suggest that the classification of deep MR in patients with CML is more stringent in PB than in BM. Our study supports the current practice to primarily use PB for long-term molecular follow-up monitoring in CML.
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http://dx.doi.org/10.1515/cclm-2019-1172DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115836PMC
July 2020

CDK4/CDK6 inhibition as a novel strategy to suppress the growth and survival of BCR-ABL1+ clones in TKI-resistant CML.

EBioMedicine 2019 Dec 21;50:111-121. Epub 2019 Nov 21.

Department of Internal Medicine I, Division of Hematology & Hemostaseology, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria; Ludwig Boltzmann Institute for Hematology & Oncology, Medical University of Vienna, Austria. Electronic address:

Purpose: Ponatinib is the only approved tyrosine kinase inhibitor (TKI) suppressing BCR-ABL1-mutated cells in chronic myeloid leukemia (CML). However, due to side effects and resistance, BCR-ABL1-mutated CML remains a clinical challenge. Hydroxyurea (HU) has been used for cytoreduction in CML for decades. We found that HU suppresses or even eliminates BCR-ABL1+ sub-clones in heavily pretreated CML patients. Based on this observation, we investigated the effects of HU on TKI-resistant CML cells in vitro.

Methods: Viability, apoptosis and proliferation of drug-exposed primary CML cells and BCR-ABL1+ cell lines were examined by flow cytometry and H-thymidine-uptake. Expression of drug targets was analyzed by qPCR and Western blotting.

Findings: HU was more effective in inhibiting the proliferation of leukemic cells harboring BCR-ABL1 or T315I-including compound-mutations compared to cells expressing wildtype BCR-ABL1. Moreover, HU synergized with ponatinib and ABL001 in inducing growth inhibition in CML cells. Furthermore, HU blocked cell cycle progression in leukemic cells, which was accompanied by decreased expression of CDK4 and CDK6. Palbociclib, a more specific CDK4/CDK6-inhibitor, was also found to suppress proliferation in primary CML cells and to synergize with ponatinib in producing growth inhibition in BCR-ABL1+ cells, suggesting that suppression of CDK4/CDK6 may be a promising concept to overcome BCR-ABL1-associated TKI resistance.

Interpretation: HU and the CDK4/CDK6-blocker palbociclib inhibit growth of CML clones expressing BCR-ABL1 or complex T315I-including compound-mutations. Clinical studies are required to confirm single drug effects and the efficacy of `ponatinib+HU´ and ´ponatinib+palbociclib´ combinations in advanced CML.

Funding: This project was supported by the Austrian Science Funds (FWF) projects F4701-B20, F4704-B20 and P30625.
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http://dx.doi.org/10.1016/j.ebiom.2019.11.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6921367PMC
December 2019

The Austrian biodatabase for chronic myelomonocytic leukemia (ABCMML) : A representative and useful real-life data source for further biomedical research.

Wien Klin Wochenschr 2019 Sep 18;131(17-18):410-418. Epub 2019 Jul 18.

Department of Internal Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Vienna, Austria.

In the Austrian biodatabase for chronic myelomonocytic leukemia (ABCMML) clinicolaboratory real-life data have been captured from 606 CMML patients from 14 different hospitals over the last 30 years. It is the only large biodatabase worldwide in which functional methods such as semisolid in vitro cultures complement modern molecular methods such as next generation sequencing. This provides the possibility to comprehensively study the biology of CMML. The aim of this study was to compare patient characteristics with published CMML cohorts and to validate established prognostic parameters in order to examine if this real-life database can serve as a representative and useful data source for further research. After exclusion of patients in transformation characteristics of 531 patients were compared with published CMML cohorts. Median values for age, leukocytes, hemoglobin, platelets, lactate dehydrogenase (LDH) and circulating blasts were within the ranges of reported CMML series. Established prognostic parameters including leukocytes, hemoglobin, blasts and adverse cytogenetics were able to discriminate patients with different outcome. Myeloproliferative (MP) as compared to myelodysplastic (MD)-CMML patients had higher values for circulating blasts, LDH, RAS-pathway mutations and for spontaneous myelomonocytic colony growth in vitro as well as more often splenomegaly. This study demonstrates that the patient cohort of the ABCMML shares clinicolaboratory characteristics with reported CMML cohorts from other countries and confirms phenotypic and genotypic differences between MP-CMML and MD-CMML. Therefore, results obtained from molecular and biological analyses using material from the national cohort will also be applicable to other CMML series and thus may have a more general significance.
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http://dx.doi.org/10.1007/s00508-019-1526-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6748886PMC
September 2019

Consensus criteria for diagnosis, staging, and treatment response assessment of T-cell prolymphocytic leukemia.

Blood 2019 10 10;134(14):1132-1143. Epub 2019 Jul 10.

The Royal Marsden Hospital, NHS Foundation Trust, London, United Kingdom.

T-cell prolymphocytic leukemia (T-PLL) is a rare, mature T-cell neoplasm with a heterogeneous clinical course. With the advent of novel treatment options that will potentially change the management of patients with T-PLL, it has become necessary to produce consensus guidelines for the design and conduct of clinical trials. The T-PLL International Study group (TPLL-ISG) set out to define standardized criteria for diagnosis, treatment indication, and evaluation of response. These criteria will facilitate comparison of results from clinical trials in T-PLL, and will thus support clinical decision making, as well as the approval of new therapeutics by healthcare authorities.
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http://dx.doi.org/10.1182/blood.2019000402DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7042666PMC
October 2019

High activation of STAT5A drives peripheral T-cell lymphoma and leukemia.

Haematologica 2020 31;105(2):435-447. Epub 2020 Jan 31.

Ludwig Boltzmann Institute for Cancer Research, Vienna, Austria

Recurrent gain-of-function mutations in the transcription factors and much more in were found in hematopoietic malignancies with the highest proportion in mature T- and natural killer-cell neoplasms (peripheral T-cell lymphoma, PTCL). No targeted therapy exists for these heterogeneous and often aggressive diseases. Given the shortage of models for PTCL, we mimicked graded STAT5A or STAT5B activity by expressing hyperactive or variants at low or high levels in the hematopoietic system of transgenic mice. Only mice with high activity levels developed a lethal disease resembling human PTCL. Neoplasia displayed massive expansion of CD8 T cells and destructive organ infiltration. T cells were cytokine-hypersensitive with activated memory CD8 T-lymphocyte characteristics. Histopathology and mRNA expression profiles revealed close correlation with distinct subtypes of PTCL. Pronounced STAT5 expression and activity in samples from patients with different subsets underline the relevance of JAK/STAT as a therapeutic target. JAK inhibitors or a selective STAT5 SH domain inhibitor induced cell death and ruxolitinib blocked T-cell neoplasia We conclude that enhanced STAT5A or STAT5B action both drive PTCL development, defining both STAT5 molecules as targets for therapeutic intervention.
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http://dx.doi.org/10.3324/haematol.2019.216986DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7012494PMC
January 2020

Molecular quantification of tissue disease burden is a new biomarker and independent predictor of survival in mastocytosis.

Haematologica 2020 31;105(2):366-374. Epub 2020 Jan 31.

Department of Laboratory Medicine, Medical University of Vienna, Vienna

A high allele burden of the D816V mutation in peripheral blood or bone marrow aspirates indicates multi-lineage hematopoietic involvement and has been associated with an aggressive clinical course of systemic mastocytosis. Since mast cells are substantially underrepresented in these liquid specimens, their mutation burden likely underestimates the tumor burden of the disease. We used a novel previously validated digital polymerase chain reaction (PCR) method for D816V analysis to systematically analyze the mutation burden in formalin-fixed, paraffin-embedded bone marrow tissue sections of 116 mastocytosis patients (91 with indolent and 25 with advanced systemic mastocytosis), and to evaluate for the first time the clinical value of the tissue mutation burden as a novel biomarker. The D816V mutation burden in the tissue was significantly higher and correlated better with bone marrow mast cell infiltration (r=0.68 0.48) and serum tryptase levels (r=0.68 0.58) compared to that in liquid specimens. Furthermore, the D816V tissue mutation burden was: (i) significantly higher in advanced than in indolent systemic mastocytosis (=0.001); (ii) predicted survival of patients in multivariate analyses independently; and (iii) was significantly reduced after response to cytoreductive therapy. Finally, digital PCR was more sensitive in detecting D816V in bone marrow sections of indolent systemic mastocytosis patients than melting curve analysis after peptide nucleic acid-mediated PCR clamping (97% 89%; <0.05). In summary, digital PCR-based measurement of D816V mutation burden in the tissue represents a novel biomarker with independent prognostic significance that can also be employed for monitoring disease progression and treatment response in systemic mastocytosis.
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http://dx.doi.org/10.3324/haematol.2019.217950DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7012478PMC
January 2020

Identification of a leukemia-initiating stem cell in human mast cell leukemia.

Leukemia 2019 11 5;33(11):2673-2684. Epub 2019 Apr 5.

Ludwig Boltzmann Institute for Hematology and Oncology, Medical University of Vienna, 1090, Vienna, Austria.

Mast cell leukemia (MCL) is a highly fatal malignancy characterized by devastating expansion of immature mast cells in various organs. Although considered a stem cell disease, little is known about MCL-propagating neoplastic stem cells. We here describe that leukemic stem cells (LSCs) in MCL reside within a CD34/CD38 fraction of the clone. Whereas highly purified CD34/CD38 cells engrafted NSG mice with fully manifesting MCL, no MCL was produced by CD34/CD38 progenitors or the bulk of KIT/CD34 mast cells. CD34/CD38 MCL cells invariably expressed CD13 and CD133, and often also IL-1RAP, but did not express CD25, CD26 or CLL-1. CD34/CD38 MCL cells also displayed several surface targets, including CD33, which was homogenously expressed on MCL LSCs in all cases, and the D816V mutant form of KIT. Although CD34/CD38 cells were resistant against single drugs, exposure to combinations of CD33-targeting and KIT-targeting drugs resulted in LSC-depletion and markedly reduced engraftment in NSG mice. Together, MCL LSCs are CD34/CD38 cells that express distinct profiles of markers and target antigens. Characterization of MCL LSCs should facilitate their purification and should support the development of LSC-eradicating curative treatment approaches in this fatal type of leukemia.
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http://dx.doi.org/10.1038/s41375-019-0460-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6839966PMC
November 2019

Clonal Hematopoiesis with Oncogenic Potential (CHOP): Separation from CHIP and Roads to AML.

Int J Mol Sci 2019 Feb 12;20(3). Epub 2019 Feb 12.

Institute of Pathology, Ludwig-Maximilians University, 80539 Munich, Germany.

The development of leukemia is a step-wise process that is associated with molecular diversification and clonal selection of neoplastic stem cells. Depending on the number and combinations of lesions, one or more sub-clones expand/s after a variable latency period. Initial stages may develop early in life or later in adulthood and include premalignant (indolent) stages and the malignant phase, defined by an acute leukemia. We recently proposed a cancer model in which the earliest somatic lesions are often age-related early mutations detectable in apparently healthy individuals and where additional oncogenic mutations will lead to the development of an overt neoplasm that is usually a preleukemic condition such as a myelodysplastic syndrome. These neoplasms may or may not transform to overt acute leukemia over time. Thus, depending on the type and number of somatic mutations, clonal hematopoiesis (CH) can be divided into CH with indeterminate potential (CHIP) and CH with oncogenic potential (CHOP). Whereas CHIP mutations usually create the molecular background of a neoplastic process, CHOP mutations are disease-related or even disease-specific lesions that trigger differentiation and/or proliferation of neoplastic cells. Over time, the acquisition of additional oncogenic events converts preleukemic neoplasms into secondary acute myeloid leukemia (sAML). In the present article, recent developments in the field are discussed with a focus on CHOP mutations that lead to distinct myeloid neoplasms, their role in disease evolution, and the impact of additional lesions that can drive a preleukemic neoplasm into sAML.
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http://dx.doi.org/10.3390/ijms20030789DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6387423PMC
February 2019

Combined chemosensitivity and chromatin profiling prioritizes drug combinations in CLL.

Nat Chem Biol 2019 03 28;15(3):232-240. Epub 2019 Jan 28.

CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria.

The Bruton tyrosine kinase (BTK) inhibitor ibrutinib has substantially improved therapeutic options for chronic lymphocytic leukemia (CLL). Although ibrutinib is not curative, it has a profound effect on CLL cells and may create new pharmacologically exploitable vulnerabilities. To identify such vulnerabilities, we developed a systematic approach that combines epigenome profiling (charting the gene-regulatory basis of cell state) with single-cell chemosensitivity profiling (quantifying cell-type-specific drug response) and bioinformatic data integration. By applying our method to a cohort of matched patient samples collected before and during ibrutinib therapy, we identified characteristic ibrutinib-induced changes that provide a starting point for the rational design of ibrutinib combination therapies. Specifically, we observed and validated preferential sensitivity to proteasome, PLK1, and mTOR inhibitors during ibrutinib treatment. More generally, our study establishes a broadly applicable method for investigating treatment-specific vulnerabilities by integrating the complementary perspectives of epigenetic cell states and phenotypic drug responses in primary patient samples.
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http://dx.doi.org/10.1038/s41589-018-0205-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6746620PMC
March 2019

Core-binding factor acute myeloid leukemia with t(8;21): Risk factors and a novel scoring system (I-CBFit).

Cancer Med 2018 09 16;7(9):4447-4455. Epub 2018 Aug 16.

Department of Leukemia, University of Texas M.D. Anderson Cancer Center, Houston, Texas.

Background: Although the prognosis of core-binding factor (CBF) acute myeloid leukemia (AML) is better than other subtypes of AML, 30% of patients still relapse and may require allogeneic hematopoietic cell transplantation (alloHCT). However, there is no validated widely accepted scoring system to predict patient subsets with higher risk of relapse.

Methods: Eleven centers in the US and Europe evaluated 247 patients with t(8;21)(q22;q22).

Results: Complete remission (CR) rate was high (92.7%), yet relapse occurred in 27.1% of patients. A total of 24.7% of patients received alloHCT. The median disease-free (DFS) and overall (OS) survival were 20.8 and 31.2 months, respectively. Age, KIT D816V mutated (11.3%) or nontested (36.4%) compared with KIT D816V wild type (52.5%), high white blood cell counts (WBC), and pseudodiploidy compared with hyper- or hypodiploidy were included in a scoring system (named I-CBFit). DFS rate at 2 years was 76% for patients with a low-risk I-CBFit score compared with 36% for those with a high-risk I-CBFit score (P < 0.0001). Low- vs high-risk OS at 2 years was 89% vs 51% (P < 0.0001).

Conclusions: I-CBFit composed of readily available risk factors can be useful to tailor the therapy of patients, especially for whom alloHCT is not need in CR1 (ie, patients with a low-risk I-CBFit score).
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http://dx.doi.org/10.1002/cam4.1733DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6144246PMC
September 2018

CD44 is a RAS/STAT5-regulated invasion receptor that triggers disease expansion in advanced mastocytosis.

Blood 2018 11 17;132(18):1936-1950. Epub 2018 Jul 17.

Division of Hematology and Hemostaseology, Department of Internal Medicine I, Medical University of Vienna, Vienna, Austria.

The Hermes receptor CD44 is a multifunctional adhesion molecule that plays an essential role in the homing and invasion of neoplastic stem cells in various myeloid malignancies. Although mast cells (MCs) reportedly express CD44, little is known about the regulation and function of this receptor in neoplastic cells in systemic mastocytosis (SM). We found that clonal CD34/CD38 stem cells, CD34/CD38 progenitor cells, and CD117/CD34 MCs invariably express CD44 in patients with indolent SM (ISM), SM with an associated hematologic neoplasm, aggressive SM, and MC leukemia (MCL). In addition, all human MCL-like cell lines examined (HMC-1, ROSA, and MCPV-1) displayed cytoplasmic and cell-surface CD44. We also found that expression of CD44 in neoplastic MCs depends on RAS-MEK and STAT5 signaling and increases with the aggressiveness of SM. Correspondingly, higher levels of soluble CD44 were measured in the sera of patients with advanced SM compared with ISM or cutaneous mastocytosis and were found to correlate with overall and progression-free survival. To investigate the functional role of CD44, a xenotransplantation model was employed using severe combined immunodeficient (SCID) mice, HMC-1.2 cells, and a short hairpin RNA (shRNA) against CD44. In this model, the shRNA-mediated knockdown of CD44 resulted in reduced MC expansion and tumor formation and prolonged survival in SCID mice compared with HMC-1.2 cells transduced with control shRNA. Together, our data show that CD44 is a RAS-MEK/STAT5-driven MC invasion receptor that correlates with the aggressiveness of SM. Whether CD44 can serve as therapeutic target in advanced SM remains to be determined in forthcoming studies.
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http://dx.doi.org/10.1182/blood-2018-02-833582DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6382065PMC
November 2018

Ludwig Boltzmann Cluster Oncology (LBC ONC): first 10 years and future perspectives.

Wien Klin Wochenschr 2018 Sep 13;130(17-18):517-529. Epub 2018 Jul 13.

Ludwig Boltzmann Cluster Oncology, Vienna, Austria.

In 2008 the Ludwig Boltzmann Cluster Oncology (LBC ONC) was established on the basis of two previous Ludwig Boltzmann Institutes working in the field of hematology and cancer research. The general aim of the LBC ONC is to improve treatment of hematopoietic neoplasms by eradicating cancer-initiating and disease-propagating cells, also known as leukemic stem cells (LSC) in the context of leukemia. In a first phase, the LBC ONC characterized the phenotype and molecular aberration profiles of LSC in various malignancies. The LSC phenotypes were established in acute and chronic myeloid leukemia, in acute lymphoblastic leukemia and in chronic lymphocytic leukemia. In addition, the concept of preleukemic (premalignant) neoplastic stem cells (pre-L-NSC) was coined by the LBC ONC and was tested in myelodysplastic syndromes and myeloproliferative neoplasms. Phenotypic characterization of LSC provided a solid basis for their purification and for the characterization of specific target expression profiles. In a second phase, molecular markers and targets were validated. This second phase is ongoing and should result in the development of new diagnostics parameters and novel, more effective, LSC-eradicating, treatment strategies; however, many issues still remain to be solved, such as sub-clonal evolution, LSC niche interactions, immunologic control of LSC, and LSC resistance. In the forthcoming years, the LBC ONC will concentrate on developing LSC-eradicating strategies, with special focus on LSC resistance, precision medicine and translation of LSC-eradicating concepts into clinical application.
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http://dx.doi.org/10.1007/s00508-018-1355-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6132878PMC
September 2018

Preclinical human models and emerging therapeutics for advanced systemic mastocytosis.

Haematologica 2018 11 5;103(11):1760-1771. Epub 2018 Jul 5.

Ludwig Boltzmann Cluster Oncology, Medical University of Vienna, Austria.

Mastocytosis is a term used to denote a group of rare diseases characterized by an abnormal accumulation of neoplastic mast cells in various tissues and organs. In most patients with systemic mastocytosis, the neoplastic cells carry activating mutations in Progress in mastocytosis research has long been hindered by the lack of suitable models, such as permanent human mast cell lines. In fact, only a few human mast cell lines are available to date: HMC-1, LAD1/2, LUVA, ROSA and MCPV-1. The HMC-1 and LAD1/2 cell lines were derived from patients with mast cell leukemia. By contrast, the more recently established LUVA, ROSA and MCPV-1 cell lines were derived from CD34 cells of non-mastocytosis donors. While some of these cell lines (LAD1/2, LUVA, ROSA and MCPV-1) do not harbor mutations, HMC-1 and ROSA cells exhibit activating mutations found in mastocytosis and have thus been used to study disease pathogenesis. In addition, these cell lines are increasingly employed to validate new therapeutic targets and to screen for effects of new targeted drugs. Recently, the ROSA subclone has been successfully used to generate a unique model of advanced mastocytosis by injection into immunocompromised mice. Such a model may allow validation of data obtained with targeted drugs directed against mastocytosis. In this review, we discuss the major characteristics of all available human mast cell lines, with particular emphasis on the use of HMC-1 and ROSA cells in preclinical therapeutic research in mastocytosis.
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http://dx.doi.org/10.3324/haematol.2018.195867DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6278969PMC
November 2018