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- Harrison, C. J., et al.
(author)
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An international study of intrachromosomal amplification of chromosome 21 (iAMP21) : cytogenetic characterization and outcome
- 2014
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In: Leukemia. - : Springer Science and Business Media LLC. - 0887-6924 .- 1476-5551. ; 28:5, s. 1015-1021
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Journal article (peer-reviewed)abstract
- Intrachromosomal amplification of chromosome 21 (iAMP21) defines a distinct cytogenetic subgroup of childhood B-cell precursor acute lymphoblastic leukaemia (BCP-ALL). To date, fluorescence in situ hybridisation (FISH), with probes specific for the RUNX1 gene, provides the only reliable detection method (five or more RUNX1 signals per cell). Patients with iAMP21 are older (median age 9 years) with a low white cell count. Previously, we demonstrated a high relapse risk when these patients were treated as standard risk. Recent studies have shown improved outcome on intensive therapy. In view of these treatment implications, accurate identification is essential. Here we have studied the cytogenetics and outcome of 530 iAMP21 patients that highlighted the association of specific secondary chromosomal and genetic changes with iAMP21 to assist in diagnosis, including the gain of chromosome X, loss or deletion of chromosome 7, ETV6 and RB1 deletions. These iAMP21 patients when treated as high risk showed the same improved outcome as those in trial-based studies regardless of the backbone chemotherapy regimen given. This study reinforces the importance of intensified treatment to reduce the risk of relapse in iAMP21 patients. This now well-defined patient subgroup should be recognised by World Health Organisation (WHO) as a distinct entity of BCP-ALL.
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- Coenen, Eva A, et al.
(author)
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Prognostic significance of additional cytogenetic aberrations in 733 de novo pediatric 11q23/MLL-rearranged AML patients : results of an international study
- 2011
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In: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 117:26, s. 7102-7111
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Journal article (peer-reviewed)abstract
- We previously demonstrated that outcome of pediatric 11q23/MLL-rearranged AML depends on the translocation partner (TP). In this multicenter international study on 733 children with 11q23/MLL-rearranged AML, we further analyzed which additional cytogenetic aberrations (ACA) had prognostic significance. ACAs occurred in 344 (47%) of 733 and were associated with unfavorable outcome (5-year overall survival [OS] 47% vs 62%, P < .001). Trisomy 8, the most frequent specific ACA (n = 130/344, 38%), independently predicted favorable outcome within the ACAs group (OS 61% vs 39%, P = .003; Cox model for OS hazard ratio (HR) 0.54, P = .03), on the basis of reduced relapse rate (26% vs 49%, P < .001). Trisomy 19 (n = 37/344, 11%) independently predicted poor prognosis in ACAs cases, which was partly caused by refractory disease (remission rate 74% vs 89%, P = .04; OS 24% vs 50%, P < .001; HR 1.77, P = .01). Structural ACAs had independent adverse prognostic value for event-free survival (HR 1.36, P = .01). Complex karyotype, defined as ≥ 3 abnormalities, was present in 26% (n = 192/733) and showed worse outcome than those without complex karyotype (OS 45% vs 59%, P = .003) in univariate analysis only. In conclusion, like TP, specific ACAs have independent prognostic significance in pediatric 11q23/MLL-rearranged AML, and the mechanism underlying these prognostic differences should be studied.
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- Holmfeldt, Linda, et al.
(author)
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The genomic landscape of hypodiploid acute lymphoblastic leukemia
- 2013
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 45:3, s. 242-252
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Journal article (peer-reviewed)abstract
- The genetic basis of hypodiploid acute lymphoblastic leukemia (ALL), a subtype of ALL characterized by aneuploidy and poor outcome, is unknown. Genomic profiling of 124 hypodiploid ALL cases, including whole-genome and exome sequencing of 40 cases, identified two subtypes that differ in the severity of aneuploidy, transcriptional profiles and submicroscopic genetic alterations. Near-haploid ALL with 24-31 chromosomes harbor alterations targeting receptor tyrosine kinase signaling and Ras signaling (71%) and the lymphoid transcription factor gene IKZF3 (encoding AIOLOS; 13%). In contrast, low-hypodiploid ALL with 32-39 chromosomes are characterized by alterations in TP53 (91.2%) that are commonly present in nontumor cells, IKZF2 (encoding HELIOS; 53%) and RB1 (41%). Both near-haploid and low-hypodiploid leukemic cells show activation of Ras-signaling and phosphoinositide 3-kinase (PI3K)-signaling pathways and are sensitive to PI3K inhibitors, indicating that these drugs should be explored as a new therapeutic strategy for this aggressive form of leukemia.
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- Sandahl, Julie Damgaard, et al.
(author)
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t(6;9)(p22; q34)/DEK-NUP214-rearranged pediatric myeloid leukemia : an international study of 62 patients
- 2014
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In: Haematologica. - : Ferrata Storti Foundation (Haematologica). - 0390-6078 .- 1592-8721. ; 99:5, s. 865-872
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Journal article (peer-reviewed)abstract
- Acute myeloid leukemia with t(6; 9)(p22; q34) is listed as a distinct entity in the 2008 World Health Organization classification, but little is known about the clinical implications of t(6; 9)-positive myeloid leukemia in children. This international multicenter study presents the clinical and genetic characteristics of 62 pediatric patients with t(6; 9)/DEKNUP214-rearranged myeloid leukemia; 54 diagnosed as having acute myeloid leukemia, representing <1% of all childhood acute myeloid leukemia, and eight as having myelodysplastic syndrome. The t(6; 9)/DEK-NUP214 was associated with relatively late onset (median age 10.4 years), male predominance (sex ratio 1.7), French-American-British M2 classification (54%), myelodysplasia (100%), and FLT3-ITD (42%). Outcome was substantially better than previously reported with a 5-year event-free survival of 32%, 5-year overall survival of 53%, and a 5-year cumulative incidence of relapse of 57%. Hematopoietic stem cell transplantation in first complete remission improved the 5-year event-free survival compared with chemotherapy alone (68% versus 18%; P<0.01) but not the overall survival (68% versus 54%; P=0.48). The presence of FLT3-ITD had a non-significant negative effect on 5-year overall survival compared with non-mutated cases (22% versus 62%; P=0.13). Gene expression profiling showed a unique signature characterized by significantly higher expression of EYA3, SESN1, PRDM2/RIZ, and HIST2H4 genes. In conclusion, t(6; 9)/DEK-NUP214 represents a unique subtype of acute myeloid leukemia with a high risk of relapse, high frequency of FLT3-ITD, and a specific gene expression signature.
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- Egli, M., et al.
(author)
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Rapid transformation of inorganic to organic and plant-available phosphorous in soils of a glacier forefield
- 2012
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In: Geoderma. - : Elsevier. - 0016-7061. ; 189-190, s. 215-226
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Journal article (peer-reviewed)abstract
- Chemical weathering of rocks or sediments is extremely important for the generation of soils, for the evolution of landscape, and as a main source of inorganic nutrients for plant growth and therefore for life. Temporal trends in weathering mechanisms, plant succession and nutrients availability in cold environments can be successfully studied in soil chronosequences along a glacier forefield. In the present paper, this was carried out in the pro-glacial area of Morteratsch. Different forms of phosphorous in the soil, stream and spring water chemistry were investigated. Apatite constitutes the main source of P, but it occurs only as a minor accessory mineral phase in the granitic/gneiss parent material. The identification of apatite was performed using SEM-EDX and cathodoluminescence. Water chemistry data indicated some calcite dissolution at the earliest phase of exposure, pyrite and - on older surfaces increasingly - feldspar weathering. Apatite also seemed to contribute to Ca which is leached from the soils. The concentrations of dissolved P in the stream and spring waters were, however, extremely low (only a few μg P/l). In the topsoil, the total stocks of P showed a slight decrease with time. Losses were rather difficult to detect even though the water fluxes through the soils and discharges are relatively high. Soil organic P is almost identical to the EDTA-extractable fraction. In an 11.5. ky-old soil outside the glacier forefield the concentration and proportions of organic P, EDTA-extractable P and inorganic P forms did not differ that much from the oldest soils (max. 150. years) of the glacier forefield. In the bulk soil, about 78% of total P was transformed into an organic form (40% already after 150. years) and, in the fine earth, about 81% (40-70% after about 150. years of soil evolution). Thus the P transformation reactions are shown to be very rapid, occur predominantly in the early phase of soil formation, and could be best described by an exponential decay model. © 2012 Elsevier B.V.
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- Gorini, C., et al.
(author)
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Non-Abelian gauge fields in the gradient expansion : generalized Boltzmann and Eilenberger equations
- 2010
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In: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 82:19
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Journal article (peer-reviewed)abstract
- We present a microscopic derivation of the generalized Boltzmann and Eilenberger equations in the presence of non-Abelian gauges for the case of a nonrelativistic disordered Fermi gas. A unified and symmetric treatment of the charge [U(1)] and spin [SU(2)] degrees of freedom is achieved. Within this framework, just as the U(1) Lorentz force generates the Hall effect, so does its SU(2)counterpart gives rise to the spin Hall effect. Considering elastic and spin-independent disorder we obtain diffusion equations for charge and spin densities and show how the interplay between an in-plane magnetic field and a time-dependent Rashba term generates in-plane charge currents.
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