| 41. |
- Hansén Nord, Karolin, et al.
(författare)
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Heterogeneous genetic profiles in soft tissue myoepitheliomas
- 2008
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Ingår i: Modern Pathology. - : Elsevier BV. - 1530-0285 .- 0893-3952. ; 21:11, s. 1311-1319
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Tidskriftsartikel (refereegranskat)abstract
- Myoepithelioma, mixed tumor and parachordoma are uncommon soft tissue tumors thought to represent morphological variants of a single tumor type. The genetic basis of these neoplasms is poorly understood. However, they morphologically resemble mixed tumor of the salivary glands (also known as pleomorphic adenoma), a tumor characterized by deregulated expression of PLAG1 or HMGA2. To evaluate a possible genetic relationship between these soft tissue and salivary gland tumors, PLAG1 expression levels and the genomic status of PLAG1 and HMGA2 were investigated in five soft tissue myoepitheliomas and one pleomorphic adenoma. In addition, all tumors were cytogenetically investigated and whole genome DNA copy number imbalances were studied in five of them. The genetic profiles were heterogeneous and the only aberration common to all soft tissue myoepitheliomas was a minimally deleted region of 3.55 Mb in chromosome band 19p13. Recurrent deletion of CDKN2A suggests that inactivation of this tumor suppressor gene is pathogenetically important in a subset. Furthermore, PLAG1 rearrangement was found in a soft tissue tumor from a patient previously treated for a salivary pleomorphic adenoma, indicating either metastasis of the salivary gland lesion or that some soft tissue tumors develop through the same mechanisms as their salivary gland counterparts.
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| 42. |
- Hansén Nord, Karolin, et al.
(författare)
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Integrative Genome and Transcriptome Analyses Reveal Two Distinct Types of Ring Chromosome in Soft Tissue Sarcomas.
- 2014
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 23:4, s. 878-888
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Tidskriftsartikel (refereegranskat)abstract
- Gene amplification is a common phenomenon in malignant neoplasms of all types. One mechanism behind increased gene copy number is the formation of ring chromosomes. Such structures are mitotically unstable and during tumor progression they accumulate material from many different parts of the genome. Hence, their content varies considerably between and within tumors. Partly due to this extensive variation, the genetic content of many ring-containing tumors remains poorly characterized. Ring chromosomes are particularly prevalent in specific subtypes of sarcoma. Here, we have combined fluorescence in situ hybridization, global genomic copy number and gene expression data on ring-containing soft tissue sarcomas and show that they harbor two fundamentally different types of ring chromosome: MDM2-positive and MDM2-negative rings. While the former are often found in an otherwise normal chromosome complement, the latter seem to arise in the context of general chromosomal instability. In line with this, sarcomas with MDM2-negative rings commonly show complete loss of either CDKN2A or RB1-both known to be important for genome integrity. Sarcomas with MDM2-positive rings instead show co-amplification of a variety of potential driver oncogenes. More than one hundred different genes were found to be involved, many of which are known to induce cell growth, promote proliferation or inhibit apoptosis. Several of the amplified and overexpressed genes constitute potential drug targets.
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| 43. |
- Hansén Nord, Karolin, et al.
(författare)
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Retained heterodisomy is associated with high gene expression in hyperhaploid inflammatory leiomyosarcoma.
- 2012
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Ingår i: Neoplasia. - : Elsevier BV. - 1522-8002. ; 14:9, s. 807-U156
-
Tidskriftsartikel (refereegranskat)abstract
- Inflammatory leiomyosarcoma (ILMS) is a soft tissue tumor that morphologically resembles conventional leiomyosarcoma (LMS) admixed with a prominent inflammatory infiltrate. Genetic data on ILMS are still limited but have suggested that this entity is characterized by hyperhaploidy (24-34 chromosomes). This low chromosome number is otherwise uncommon in neoplasia and has been found only in 0.2% to 0.3% of cytogenetically investigated tumors. Here, three ILMS were investigated using cytogenetic, single-nucleotide polymorphism (SNP) array, and global gene expression analyses. All cases displayed a hyperhaploid origin. Combined with previously reported cases, hyperhaploidy has been found in six of seven cytogenetically investigated ILMS. The copy number distribution of individual chromosomes is clearly nonrandom; the hyperhaploid clones of all six cases displayed disomy for chromosomes 5 and 20, and two copies of chromosomes 18, 21, and 22 were also common. All chromosomes identified as disomic showed a biparental origin by SNP array analysis; whether this is of pathogenetic importance is not known. Compared with conventional LMS, ILMS had a distinct gene expression signature. Furthermore, the number of chromosome copies correlated well with gene expression levels; disomic chromosomes showed higher gene expression levels than monosomic chromosomes, a finding that has not previously been reported for hyperhaploid tumors. Taken together, our findings suggest that disomy for some chromosomes, notably 5 and 20, as well as distorted gene expression achieved through massive loss of other chromosomes are essential features of ILMS.
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| 44. |
- Hansén Nord, Karolin, et al.
(författare)
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Tiling resolution array comparative genomic hybridization analysis of a fibrosarcoma of bone.
- 2007
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Ingår i: Cancer Genetics and Cytogenetics. - : Elsevier BV. - 0165-4608. ; 172:1, s. 80-83
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Tidskriftsartikel (refereegranskat)abstract
- Fibrosarcoma of bone is a rare malignant tumor accounting for less than 5% of all primary malignant bone neoplasms. There is very limited knowledge regarding the molecular genetics of this tumor, and there are no cytogenetic data available. In the present study, a fibrosarcoma deriving from the left iliac bone of a 10-year-old girl was characterized using cytogenetics, fluorescence in situ hybridization (FISH), and whole genome tiling resolution array comparative genomic hybridization (CGH). Cytogenetic and FISH analyses revealed a ring chromosome 6 as the sole acquired aberration, a finding corroborated by array CGH. The ring formation, however, did not result in any gain of genetic material. Nor did the breakpoints in 6p25 and 6q14 seem to affect any known gene loci in such a way that the ring formation could have resulted in the creation of a fusion gene or in the exchange of regulatory sequences. Thus, a reasonable interpretation of the pathogenetic significance of the ring formation would be that it resulted in the loss of one or more putative tumor suppressor gene loci distal to the two breakpoints.
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| 45. |
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| 46. |
- Heim, Sverre, et al.
(författare)
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A new specific chromosomal rearrangement, t(8;16) (p11;p13), in acute monocytic leukaemia
- 1987
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Ingår i: British Journal of Haematology. - 0007-1048. ; 66:3, s. 323-326
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Tidskriftsartikel (refereegranskat)abstract
- The translocation t(8;16) (p11;p13) was found as the sole deviation from the normal karyotype in three patients with acute monocytic leukaemia. The bone marrow morphology was strikingly similar in the two cases where smears were available for re-evaluation: the leukaemic cells showed signs of differentiation, and active erythrophagocytosis was a particularly conspicuous feature. We suggest that t(8;16) (p11;p13) represents a new consistent abnormality in acute monocytic leukaemia, specifically associated with the differentiated subtype (M5b) and with pronounced phagocytic activity by the leukaemic monocytes.
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| 47. |
- Heim, Sverre, et al.
(författare)
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Bone marrow karyotypes in 94 children with acute leukemia
- 1990
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Ingår i: European Journal of Haematology. - 1600-0609. ; 44:4, s. 227-233
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Tidskriftsartikel (refereegranskat)abstract
- During the last 10 years, we have cytogenetically analyzed at diagnosis bone marrow cells from a total of 94 children with acute leukemia. Of the 78 children with acute lymphatic leukemia (ALL), 53 (68%) had clonal acquired chromosome abnormalities; in the group with acute nonlymphatic leukemia (ANLL), the corresponding proportion was 13 out of 16 (81%). Among the cytogenetically abnormal ALL patients, the most numerous subset was the hyperdiploid cases with stemlines containing 51 or more chromosomes (26 of 53 abnormal cases; 49%). This is a clearly higher proportion than has been reported in large series from other centers. Deletions of 6q were present in 8 cases and rearrangements of 12p in 5. Of the 7 T-cell ALLs, 3 had translocations of the distal part of 7q, i.e., of the region where the beta T-cell receptor is encoded. Only 2 of 26 (8%) patients with leukemic stemlines with more than 50 chromosomes have relapsed; the remainder are still in first remission (mean observation time 42 months). This may be contrasted with 6 of 25 (24%) relapses among the cytogenetically normal (observation time 41 months), and 8 of 27 (30%) relapses among ALL patients with aberrations but with less than 51 chromosomes (observation time 26 months). Our results support the conclusion that the finding of a markedly hyperdiploid leukemia karyotype is indicative of good prognosis in ALL.
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| 48. |
- Heim, Sverre, et al.
(författare)
-
High resolution banding analysis of the reciprocal translocation t(6;9) in acute nonlymphocytic leukemia
- 1986
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Ingår i: Cancer Genetics and Cytogenetics. - 0165-4608. ; 22:3, s. 195-201
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Tidskriftsartikel (refereegranskat)abstract
- The cytogenetic, hematologic, and clinical characteristics of a 13-year-old girl with acquired t(6;9)(p23;q34) and dysmyelopoietic syndrome developing into acute myelomonocytic leukemia are described, bringing the total number of patients with t(6;9) and hematologic disease described in the literature up to 19. The diagnosis has been acute myeloid leukemia in the great majority of these patients; only four have had acute myelomonocytic leukemia. High resolution analysis at the 550 band stage localized the breakpoints in chromosomes #6 and #9 to p23 and 9q34.3, respectively. Previous investigations employing high resolution cytogenetics have mapped the typical 9q breakage site in chronic myeloid leukemia to 9q34.1. In situ hybridization studies have demonstrated that the cellular oncogene c-abl remains on the derivative 9q+ chromosome in t(6;9), whereas it is moved to the Ph marker in t(9;22). Thus, the combined data indicate that c-abl is located between 9q34.1 and 9q34.3, i.e., in subband 9q34.2 or its immediate vicinity.
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| 49. |
- Heim, Sverre, et al.
(författare)
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New structural chromosomal rearrangements in congenital leukemia
- 1987
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Ingår i: Leukemia. - 1476-5551. ; 1:1, s. 16-23
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Tidskriftsartikel (refereegranskat)abstract
- The karyotypic abnormalities and clinical data on three patients in whom acute leukemia was diagnosed within the first 6 months of life are presented. The four structural chromosomal rearrangements detected in the bone marrow from these patients, i.e., t(7;12)(q36;p13) and t(1;19)(q11;q11) in case 1, t(2;10;11;12)(q21q31;p13;q13;q24) in case 2, and t(11;19)(q23;p13) in case 3, have not previously been associated with congenital leukemia. Acquired chromosomal changes have until now been reported in only 31 leukemic infants in this age group. Of the total material, 18 patients had acute lymphoblastic leukemia and 16 had acute nonlymphocytic leukemia. The by far most frequently recorded cytogenetic aberration has been t(4q;11q), seen in 14 cases of lymphoblastic leukemia. Although t(4q;11q) has not been found in a single patient with acute nonlymphocytic leukemia, these leukemias have often had other rearrangements involving the same region of 11q. Hence, genetic material around 4q21 may be active in lymphocytic differentiation, whereas gene(s) in 11q23 may be important in the neoplastic process in a less cell-type specific manner and perhaps particularly vulnerable to neoplastic rearrangement in fetal life. The finding of four cases out of 34 with translocations between 11q23 and chromosome 19 indicates that this rearrangement might characterize a specific cytogenetic subgroup of leukemia in the very young.
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| 50. |
- Heim, Sverre, et al.
(författare)
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Reciprocal translocation (11;19)(q23;p13) in congenital acute lymphoblastic leukemia
- 1986
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Ingår i: Cancer Genetics and Cytogenetics. - : Elsevier BV. - 0165-4608. ; 23:3, s. 239-244
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Tidskriftsartikel (refereegranskat)abstract
- The cytogenetic, clinical, and immunologic findings ina 4-month-old girl with acute lymphoblastic leukemia (ALL) are reported. The malignant lymphoblasts were characterized cytogenetically by the reciprocal translocation t(11;19)(q23;p13); immunologically by an immature pre-B-ALL phenotype. In spite of the high-risk nature of the leukemia, the patient attained complete remission relatively quickly and is still free of disease 3 years after diagnosis. Because the only two previously reported ALL patients with t(11;19) also seem to have responded well to therapy, this cytogenetic abnormality might turn out to be an indicator of favorable prognosis in ALL.
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