| 1. |
- Borssen, Magnus, et al.
(författare)
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Promoter DNA methylation pattern identifies prognostic subgroups in childhood T-cell acute lymphoblastic leukemia.
- 2013
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 8:6
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Tidskriftsartikel (refereegranskat)abstract
- Treatment of pediatric T-cell acute lymphoblastic leukemia (T-ALL) has improved, but there is a considerable fraction of patients experiencing a poor outcome. There is a need for better prognostic markers and aberrant DNA methylation is a candidate in other malignancies, but its potential prognostic significance in T-ALL is hitherto undecided.
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| 2. |
- Fogelstrand, Linda, 1974, et al.
(författare)
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Prognostic Implications of Mutations in NOTCH1 and FBXW7 in Childhood T-ALL Treated According to the NOPHO ALL-1992 and ALL-2000 Protocols
- 2014
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Ingår i: Pediatric Blood & Cancer. - : Wiley-Blackwell. - 1545-5009 .- 1545-5017. ; 61:3, s. 424-430
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Tidskriftsartikel (refereegranskat)abstract
- Background In children, T-cell acute lymphoblastic leukemia (T-ALL) has inferior prognosis compared with B-cell precursor ALL. In order to improve survival, individualized treatment strategies and thus risk stratification algorithms are warranted, ideally already at the time of diagnosis.Procedure We analyzed the frequency and prognostic implication of mutations in NOTCH1 and FBXW7 in 79 cases of Swedish childhood T-ALL treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL-1992 and ALL-2000 protocols. In a subgroup of patients, we also investigated the functional relevance of NOTCH1 mutations measured as expression of the HES1, MYB, and MYC genes.Results Forty-seven of the cases (59%) displayed mutations in NOTCH1 and/or FBXW7. There was no difference in overall (P=0.14) or event-free survival (EFS) (P=0.10) in patients with T-ALL with mutation(s) in NOTCH1/FBXW7 compared with patients with T-ALL without mutations in any of these genes. T-ALL carrying NOTCH1 mutations had increased HES1 and MYB mRNA expression (HES1 9.21.9 (mean +/- SEM), MYB 8.7 +/- 0.8 (mean +/- SEM)) compared to T-ALL with wild-type NOTCH1 (HES1 1.8 +/- 0.7, MYB 5.1 +/- 1.2, P=0.02 and 0.008, respectively). In cases of T-ALL with high HES1 expression, improved overall (P=0.02) and EFS (P=0.028) was seen.Conclusions Increased NOTCH activity, reflected by increased HES1 expression, is associated with improved outcome in pediatric T-ALL, but its role as a diagnostic tool or a therapeutic target in future clinical treatment protocols remains to be elucidated. Pediatr Blood Cancer 2014;61:424-430. (c) 2013 Wiley Periodicals, Inc.
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| 3. |
- Karrman, Kristina, et al.
(författare)
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Comprehensive genetic characterization of pediatric T-cell acute lymphoblastic leukemia
- 2014
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Ingår i: Blood. - 1528-0020. ; 124:21, s. 1084-1084
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Konferensbidrag (refereegranskat)abstract
- A comprehensive genetic characterization comprising conventional chromosome banding, fluorescence in situ hybridization (FISH), and single nucleotide polymorphism (SNP) array analyses as well as large-scale sequencing of 75 genes were performed on a consecutive series of 47 pediatric T-cell acute lymphoblastic leukemia (T-ALL) patients. An abnormal karyotype was identified in 46% of the cases. Recurrent cytogenetic aberrations comprised T-cell receptor (TCR) translocations and deletions of 6q and 9p. FISH analyses of TCR rearrangements were positive in 26% of the investigated cases. The vast majority (37/39; 95%) of cases analyzed by SNP arrays displayed aberrations, with a median of 3 changes (range 0-11) per case. The genes recurrently deleted were CDKN2A, CDKN2B, LEF1, PTEN, RBI, and STIL. One case displayed chromothripsis involving 6q. No case had a whole chromosome uniparental isodisomy (wUPID); in fact, only one T-ALL of 123 informative cases in the literature has had a wUPID. However, segmental UPIDs (sUPIDs) were seen in 44% of the present cases, with most being sUPID9p. CDKN2A was homozygously deleted in all cases with sUPID9p, with a heterozygous deletion occurring prior to the sUPID9p in all instances. There was no evidence for chromosomal instability when comparing diagnostic and relapse samples. Among the genes sequenced, 14 were mutated in 28 cases. The genes targeted are involved in signaling transduction, epigenetic regulation, and transcription. In some cases, NOTCH1 mutations were seen in minor subclones and lost at relapse, showing that such mutations also can be secondary events. These findings support a multistep leukemogenic process.
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| 4. |
- Karrman, Kristina
(författare)
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Genetic Characterization of Pediatric T-cell Acute Lymphoblastic Leukemia
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of my thesis has been to characterize genetically pediatric T-cell acute lymphoblastic leukemia (T-ALL). Articles I and II focus on molecular characterization of translocations involving T-cell receptor (TCR) loci. These types of aberration are characteristic for T-ALL and have previously proved pivotal in the identification of genes implicated in leukemogenesis. The translocation t(12;14)(p13;q11) was shown to result in overexpression of CCND2. The t(12;14) is the first neoplasia-associated translocation shown to result in overexpression of CCND2 and the first example of a targeted deregulation of a member of the cyclin-encoding gene family in T-ALL. Cyclin D proteins are crucial to the cell cycle machinery and hence potential oncogenes. The second translocation cloned, t(X;7)(q22;q34), had not previously been reported in a neoplastic disorder. Breakpoint analysis revealed IRS4 as a novel translocation partner to a TCR locus, resulting in deregulated IRS4 expression, both at the gene and protein level. IRS4 plays an important part in several intracellular signalling cascades, including PI3K-AKT, known to be activated in T-ALL. In a subsequent work, I showed that IRS4 can also be targeted by alternative mechanisms in T-ALL, apart from TCR translocations, namely by mutations (Article IV). In Article III, clinical characteristics and cytogenetic aberrations were ascertained and reviewed in a large, population-based Nordic series of 285 pediatric T-ALLs. Survival analyses revealed a correlation between rare TCR translocations and inferior outcome, an association that awaits confirmation in a separate study. Finally, I used several different techniques – fluorescence in situ hybridization, single nucleotide polymorphism (SNP) array, and deep sequencing of 75 selected candidate genes – to characterize co-operative genetic aberrations in a consecutive series of paediatric T-ALL (Article V). One common change identified by SNP array was segemtal uniparental isodisomy (sUPID). This aberration was seen in 44% of the investigated cases, with most being sUPID9p that always were associated with homozygous CDKN2A deletions, with a heterozygous deletion occurring prior to the sUPID9p in all instances. Among the 75 genes investigated by deep sequencing, 14 were mutated in 28 cases. The genes targeted are involved in signalling transduction, epigenetic regulation, and transcription. In some cases, NOTCH1 mutations were seen in minor subclones and lost at relapse, showing that such mutations also can be secondary events. These findings support a multistep leukemogenic process in pediatric T-ALL. In summary, through different approaches and by various methods, the articles included in this thesis have deciphered genetic aberrations in pediatric T-ALL, contributing to a better understanding of leukemogenesis.
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