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- Tehranchi, Ramin, et al.
(författare)
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Persistent malignant stem cells in del(5q) myelodysplasia in remission.
- 2010
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 363:11, s. 1025-1037
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The in vivo clinical significance of malignant stem cells remains unclear. METHODS: Patients who have the 5q deletion (del[5q]) myelodysplastic syndrome (interstitial deletions involving the long arm of chromosome 5) have complete clinical and cytogenetic remissions in response to lenalidomide treatment, but they often have relapse. To determine whether the persistence of rare but distinct malignant stem cells accounts for such relapses, we examined bone marrow specimens obtained from seven patients with the del(5q) myelodysplastic syndrome who became transfusion-independent while receiving lenalidomide treatment and entered cytogenetic remission. RESULTS: Virtually all CD34+, CD38+ progenitor cells and stem cells that were positive for CD34 and CD90, with undetectable or low CD38 (CD38−/low), had the 5q deletion before treatment. Although lenalidomide efficiently reduced these progenitors in patients in complete remission, a larger fraction of the minor, quiescent, CD34+,CD38-/low, CD90+ del(5q) stem cells as well as functionally defined del(5q) stem cells remained distinctly resistant to lenalidomide. Over time, lenalidomide resistance developed in most of the patients in partial and complete remission, with recurrence or expansion of the del(5q) clone and clinical and cytogenetic progression. CONCLUSIONS: In these patients with the del(5q) myelodysplastic syndrome, we identified rare and phenotypically distinct del(5q) myelodysplastic syndrome stem cells that were also selectively resistant to therapeutic targeting at the time of complete clinical and cytogenetic remission. (Funded by the EuroCancerStemCell Consortium and others.)
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| 4. |
- Biloglav, Andrea, et al.
(författare)
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SFPQ-ABL1-positive B-cell precursor acute lymphoblastic leukemias
- 2020
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Ingår i: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257 .- 1098-2264.
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, a subgroup of B‐cell precursor acute lymphoblastic leukemia (BCP ALL) without an established abnormality (“B‐other”) has been shown to be characterized by rearrangements of ABL1 , ABL2 , CSF1R , or PDGFRB (a.k.a. ABL‐class genes). Using FISH with probes for these genes, we screened 55 pediatric and 50 adult B‐other cases. Three (6%) of the adult but none of the childhood B‐other cases were positive for ABL‐class aberrations. RT‐PCR and sequencing confirmed a rare SFPQ‐ABL1 fusion in one adult B‐other case with t(1;9)(p34;q34). Only six SFPQ ‐ABL1 ‐positive BCP ALLs have been reported, present case included. A review of these shows that all harbored fusions between exon 9 of SFPQ and exon 4 of ABL1 , that the fusion is typically found in adolescents/younger adults without hyperleukocytosis, and that IKZF1 deletions are recurrent. The few patients not treated with tyrosine kinase inhibitors (TKIs) and/or allogeneic stem cell transplantation relapsed, strengthening the notion that TKI should be added to the therapy of SFPQ ‐ABL1 ‐positive BCP ALL.
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- Gunnarsson, Rebeqa, et al.
(författare)
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Mutation, methylation, and gene expression profiles in dup(1q)-positive pediatric B-cell precursor acute lymphoblastic leukemia
- 2018
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Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 0887-6924 .- 1476-5551. ; 32:10, s. 2117-2125
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Tidskriftsartikel (refereegranskat)abstract
- High-throughput sequencing was applied to investigate the mutation/methylation patterns on 1q and gene expression profiles in pediatric B-cell precursor acute lymphoblastic leukemia (BCP ALL) with/without (w/wo) dup(1q). Sequencing of the breakpoint regions and all exons on 1q in seven dup(1q)-positive cases revealed non-synonymous somatic single nucleotide variants (SNVs) in BLZF1, FMN2, KCNT2, LCE1C, NES, and PARP1. Deep sequencing of these in a validation cohort w (n = 17)/wo (n = 94) dup(1q) revealed similar SNV frequencies in the two groups (47% vs. 35%; P = 0.42). Only 0.6% of the 36,259 CpGs on 1q were differentially methylated between cases w (n = 14)/wo (n = 13) dup(1q). RNA sequencing of high hyperdiploid (HeH) and t(1;19)(q23;p13)-positive cases w (n = 14)/wo (n = 52) dup(1q) identified 252 and 424 differentially expressed genes, respectively; only seven overlapped. Of the overexpressed genes in the HeH and t(1;19) groups, 23 and 31%, respectively, mapped to 1q; 60-80% of these encode nucleic acid/protein binding factors or proteins with catalytic activity. We conclude that the pathogenetically important consequence of dup(1q) in BCP ALL is a gene-dosage effect, with the deregulated genes differing between genetic subtypes, but involving similar molecular functions, biological processes, and protein classes.
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- 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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| 10. |
- Karrman, Kristina, et al.
(författare)
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Deep sequencing and SNP array analyses of pediatric T-cell acute lymphoblastic leukemia reveal NOTCH1 mutations in minor subclones and a high incidence of uniparental isodisomies affecting CDKN2A
- 2015
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Ingår i: Journal of Hematology & Oncology. - : Springer Science and Business Media LLC. - 1756-8722. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Pediatric T-cell acute lymphoblastic leukemia (T-ALL) is a genetically heterogeneous disease that arises in a multistep fashion through acquisition of several genetic aberrations, subsequently giving rise to a malignant, clonal expansion of T-lymphoblasts. The aim of the present study was to identify additional as well as cooperative genetic events in T-ALL.Methods: A population-based pediatric T-ALL series comprising 47 cases was investigated by SNP array and deep sequencing analyses of 75 genes, in order to ascertain pathogenetically pertinent aberrations and to identify cooperative events.Results: The majority (92%) of cases harbored copy number aberrations/uniparental isodisomies (UPIDs), with a median of three changes (range 0-11) per case. The genes recurrently deleted comprised CDKN2A, CDKN2B, LEF1, PTEN, RBI, and STIL. No case had a whole chromosome UPID; in fact, literature data show that this is a rare phenomenon in T-ALL. However, segmental UPIDs (sUPIDs) were seen in 42% of our 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 sequenced, 14 (19%) were mutated in 28 (72%) of 39 analyzed 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; thus, such mutations can be secondary events.Conclusions: Deep sequencing and SNP array analyses of T-ALL revealed lack of wUPIDs, a high proportion of sUPID9p targeting CDKN2A, NOTCH1 mutations in subclones, and recurrent mutations of genes involved in signaling transduction, epigenetic regulation, and transcription.
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