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- Holmfeldt, Linda, et al.
(författare)
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The genomic landscape of hypodiploid acute lymphoblastic leukemia
- 2013
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 45:3, s. 242-252
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Tidskriftsartikel (refereegranskat)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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| 2. |
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| 3. |
- Buitenkamp, Trudy D., et al.
(författare)
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Acute lymphoblastic leukemia in children with Down syndrome : a retrospective analysis from the Ponte di Legno study group
- 2014
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 123:1, s. 70-77
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Tidskriftsartikel (refereegranskat)abstract
- Children with Down syndrome (DS) have an increased risk of B-cell precursor (BCP) acute lymphoblastic leukemia (ALL). The prognostic factors and outcome of DS-ALL patients treated in contemporary protocols are uncertain. We studied 653 DS-ALL patients enrolled in 16 international trials from 1995 to 2004. Non-DS BCP-ALL patients from the Dutch Child Oncology Group and Berlin-Frankfurt-Munster were reference cohorts. DS-ALL patients had a higher 8-year cumulative incidence of relapse (26% +/- 2% vs 15% +/- 1%, P < .001) and 2-year treatment-related mortality (TRM) (7% +/- 1% vs 2.0% +/- < 1%, P < .0001) than non-DS patients, resulting in lower 8-year event-free survival (EFS) (64% +/- 2% vs 81% +/- 2%, P < .0001) and overall survival (74% +/- 2% vs 89% +/- 1%, P < .0001). Independent favorable prognostic factors include age <6 years (hazard ratio [HR] = 0.58, P = .002), white blood cell (WBC) count <10 x 10(9)/L (HR = 0.60, P = .005), and ETV6-RUNX1 (HR = 0.14, P = .006) for EFS and age (HR = 0.48, P < .001), ETV6-RUNX1 (HR = 0.1, P = .016) and high hyperdiploidy (HeH) (HR = 0.29, P = .04) for relapse-free survival. TRM was the major cause of death in ETV6-RUNX1 and HeH DS-ALLs. Thus, while relapse is the main contributor to poorer survival in DS-ALL, infection-associated TRM was increased in all protocol elements, unrelated to treatment phase or regimen. Future strategies to improve outcome in DS-ALL should include improved supportive care throughout therapy and reduction of therapy in newly identified good-prognosis subgroups.
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| 4. |
- Åhsberg, Josefine
(författare)
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Molecular mechanisms in lymphoid restriction : securing the B lineage fate
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- With the work in this thesis I have aimed to deepen the understanding of the mechanisms behind the development of different blood cell lineages with a specific focus on B cell development.To understand the interplay between extracellular signaling and transcription factor networks in early lymphoid development we investigated the functional collaborations of FLT3 and IL7R. We found that signaling via FLT3 and IL7R act in powerful synergy on proliferation of common lymphoid progenitors (CLPs). In addition to a role in expansion of progenitor cells we provided evidence for that IL7R signaling play a crucial role in B-cell commitment. IL7 deficient mice display a dramatic block in development before functional lineage restriction in the Ly6D+ CLP-compartment. The few Ly6D+CLPs that do develop have reduced mRNA levels of transcription factor EBF1, a protein with crucial functions in lineage restriction and activation of the B-lymphoid program. One crucial function of EBF1 is to activate Pax5. Even though Pax5 deficient fetal liver cells upon transplantation to congenic hosts will generate an abundance of cells with an activated B-lineage transcriptional program, the pro-B cells have disrupted regulation of non-B-lineage transcripts and a propensity to develop into T- and NK-cells in vitro. Both the activation of the B-lineage program and lineage restriction was dependent on the dose of transcription factors. Mice carrying a heterozygous mutation for the transcription factor E2A had slightly reduced relative frequency of progenitor cells and an impaired B-lineage specification in CLPs. Loss of one allele of Ebf1 resulted in reduced surface expression of IL2Rα and pre-B cell receptor (BCR), reduced IL7-response in vitro, and disrupted cell cycle dynamics in pro- and pre-B cells. While heterozygous loss of Pax5 did not result in any dramatic phenotype, the combined loss of one allele of Pax5 and one allele of Ebf1 (Pax5+/-Ebf1+/-) had a dramatic effect on lineage plasticity in B-cell progenitors compared to the single heterozygotes. Furthermore, these Pax5+/-Ebf1+/- mice developed spontaneous, transplantable pro-B cell tumors and had a significantly reduced probability to survive over time. The transformed cells show high in vitro plasticity and tumor cells with induced overexpression of intracellular Notch1 can transform into T-lineage cell in vivo.The data presented in this thesis add important pieces of information to the field of developmental hematopoiesis. By increasing the analytical depth of development in normal circumstances, and by understanding the consequence of genetic mutations in relation to cell type, we hope to contribute to the understanding of hematopoietic development in health and disease.
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