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- Fioretos, Thoas, et al.
(författare)
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Fusion of the BCR and the fibroblast growth factor receptor-1 (FGFR1) genes as a result of t(8;22)(p11;q11) in a myeloproliferative disorder: the first fusion gene involving BCR but not ABL
- 2001
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Ingår i: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257. ; 98:11, s. 558-558
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Tidskriftsartikel (refereegranskat)abstract
- Constitutive activation of tyrosine kinases as a consequence of chromosomal translocations, forming fusion genes, plays an important role in the development of hematologic malignancies, in particular, myeloproliferative syndromes (MPSs). In this respect, the t(9;22)(q34;q11) that results in the BCR/ABL fusion gene in chronic myeloid leukemia is one of the best-studied examples. The fibroblast growth factor receptor 1 (FGFR1) gene at 8p11 encodes a transmembrane receptor tyrosine kinase and is similarly activated by chromosomal translocations, in which three alternative genes-ZNF198 at 13q12, CEP110 at 9q34, and FOP at 6q27-become fused to the tyrosine kinase domain of FGFR1. These 8p11-translocations are associated with characteristic morphologic and clinical features, referred to as "8p11 MPS." In this study, we report the isolation and characterization of a novel fusion gene in a hematologic malignancy with a t(8;22)(p11;q11) and features suggestive of 8p11 MPS. We show that the breakpoints in the t(8;22) occur within introns 4 and 8 of the BCR and FGFR1 genes, respectively. On the mRNA level, the t(8;22) results in the fusion of BCR exons 1-4 in-frame with the tyrosine kinase domain of FGFR1 as well as in the expression of a reciprocal FGFR1/BCR chimeric transcript. By analogy with data obtained from previously characterized fusion genes involving FGFR1 and BCR/ABL, it is likely that the oligomerization domain contributed by BCR is critical and that its dimerizing properties lead to aberrant FGFR1 signaling and neoplastic transformation.
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- Fioretos, Thoas, et al.
(författare)
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Isochromosome 17q in blast crisis of chronic myeloid leukemia and in other hematologic malignancies is the result of clustered breakpoints in 17p11 and is not associated with coding TP53 mutations
- 1999
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Ingår i: Blood. - 1528-0020. ; 94:1, s. 225-232
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Tidskriftsartikel (refereegranskat)abstract
- An isochromosome of the long arm of chromosome 17, i(17q), is the most frequent genetic abnormality observed during the disease progression of Philadelphia chromosome-positive chronic myeloid leukemia (CML), and has been described as the sole anomaly in various other hematologic malignancies. The i(17q) hence plays a presumably important pathogenetic role both in leukemia development and progression. This notwithstanding, the molecular consequences of this abnormality have not been investigated in detail. We have analyzed 21 hematologic malignancies (8 CML in blast crisis, 8 myelodysplastic syndromes [MDS], 2 acute myeloid leukemias, 2 chronic lymphocytic leukemias, and 1 acute lymphoblastic leukemia) with i(17q) by fluorescence in situ hybridization (FISH). Using a yeast artificial chromosome (YAC) contig, derived from the short arm of chromosome 17, all cases were shown to have a breakpoint in 17p. In 12 cases, the breaks occurred within the Smith-Magenis Syndrome (SMS) common deletion region in 17p11, a gene-rich region which is genetically unstable. In 10 of these 12 cases, we were able to further map the breakpoints to specific markers localized within a single YAC clone. Six other cases showed breakpoints located proximally to the SMS common deletion region, but still within 17p11, and yet another case had a breakpoint distal to this region. Furthermore, using chromosome 17 centromere-specific probes, it could be shown that the majority of the i(17q) chromosomes (11 of 15 investigated cases) were dicentric, ie, they contained two centromeres, strongly suggesting that i(17q) is formed through an intrachromosomal recombination event, and also implicating that the i(17q), in a formal sense, should be designated idic(17)(p11). Because i(17q) formation results in loss of 17p material, potentially uncovering the effect of a tumor suppressor on the remaining 17p, the occurrence of TP53 mutations was studied in 17 cases by sequencing the entire coding region. In 16 cases, no TP53 mutations were found, whereas one MDS displayed a homozygous deletion of TP53. Thus, our data suggest that there is no association between i(17q) and coding TP53 mutations, and that another tumor suppressor gene(s), located in proximity of the SMS common deletion region, or in a more distal location, is of pathogenetic importance in i(17q)-associated leukemia.
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- Fioretos, Thoas, et al.
(författare)
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No evidence for genomic imprinting of the human BCR gene
- 1994
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Ingår i: Blood. - 1528-0020. ; 83:12, s. 3441-3444
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Tidskriftsartikel (refereegranskat)abstract
- Chronic myeloid leukemias and 5% to 20% of acute lymphoid leukemias are characterized by the Philadelphia chromosome, a reciprocal chromosomal translocation, t(9;22)(q34;q11), generating BCR-ABL and ABL-BCR fusion genes. Cytogenetic studies have recently shown a preferential involvement of the paternally derived chromosome 9 and the maternally derived chromosome 22 in this translocation, indicating that imprinting might be involved in the formation or selection of the translocation. In this study, we have identified a BamHI polymorphism in the coding region of BCR exon 1, allowing us to investigate whether both BCR alleles are transcribed. By using a reverse transcriptase-polymerase chain reaction assay, we show that both BCR alleles are expressed in the peripheral blood cells of normal individuals.
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- Fioretos, Thoas
(författare)
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Why B(-)other? About the gap of unknowns in ALL
- 2022
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 139:24, s. 3455-3457
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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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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- Lilljebjörn, Henrik, et al.
(författare)
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New oncogenic subtypes in pediatric B-cell precursor acute lymphoblastic leukemia
- 2017
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 130:12, s. 1395-1401
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Forskningsöversikt (refereegranskat)abstract
- Until recently, 20% to 30% of pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL) could not be classified into any of the established molecular subtypes. Recent molecular studies of such cases have, however, further clarified their mutational spectrum and identified new oncogenic subtypes consisting of cases with DUX4 rearrangements, ETV6-RUNX1–like gene expression, MEF2D rearrangements, and ZNF384 rearrangements. In this review, we describe these new subtypes, which account for up to 50% of previously unclassified pediatric BCP-ALL cases.
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