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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Bottillo, Irene, et al.
(författare)
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Germline and somatic NF1 mutations in sporadic and NF1-associated malignant peripheral nerve sheath tumours
- 2009
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Ingår i: Journal of Pathology. - : Wiley. - 0022-3417 .- 1096-9896. ; 217:5, s. 693-701
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Tidskriftsartikel (refereegranskat)abstract
- Malignant peripheral nerve sheath tumours (MPNSTs) are a malignancy occurring with increased frequency in patients with neurofibromatosis type 1 (NF1). In contrast to the well-known spectrum of germline NF1 mutations, the information on somatic mutations in MPNSTs is limited. In this study, we screened NF1, KRAS, and BRAF in 47 MPNSTs from patients with (n = 25) and without (n = 22) NF1. In addition, DNA from peripheral blood and cutaneous neurofibroma biopsies from, respectively, 14/25 and 7/25 of the NF1 patients were analysed. Germline NF1 mutations were detected in ten NF1 patients, including three frameshift, three nonsense, one missense, one splicing alteration, and two large deletions. Somatic NF1 mutations were found in 10/25 (40%) NF1-associated MPNSTs, in 3/7 (43%) neurofibromas, and in 9/22 (41%) sporadic MPNSTs. Large genomic copy number changes accounted for 6/10 and 7/13 somatic mutations in NF1-associated and sporadic MPNSTs, respectively. Two NF1-associated and 13 sporadic MPNSTs did not show any NF1 mutation. A major role of the KRAS and BRAF genes was ruled out. The spectrum of germline NF1 mutations in neurofibromatosis patients with MPNST is different from the spectrum of somatic mutations seen in MPNSTs. However, the somatic events share common characteristics with the NF1-related and the sporadic tumours. Copyright (C) 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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| 3. |
- Burocziova, Monika, et al.
(författare)
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Truncated PPM1D impairs stem cell response to genotoxic stress and promotes growth of APC-deficient tumors in the mouse colon
- 2019
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Ingår i: Cell Death and Disease. - : NATURE PUBLISHING GROUP. - 2041-4889. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Protein phosphatase magnesium-dependent 1 delta (PPM1D) terminates cell response to genotoxic stress by negatively regulating the tumor suppressor p53 and other targets at chromatin. Mutations in the exon 6 of the PPM1D result in production of a highly stable, C-terminally truncated PPM1D. These gain-of-function PPM1D mutations are present in various human cancers but their role in tumorigenesis remains unresolved. Here we show that truncated PPM1D impairs activation of the cell cycle checkpoints in human non-transformed RPE cells and allows proliferation in the presence of DNA damage. Next, we developed a mouse model by introducing a truncating mutation in the PPM1D locus and tested contribution of the oncogenic PPM1D(T) allele to colon tumorigenesis. We found that p53 pathway was suppressed in colon stem cells harboring PPM1D(T) resulting in proliferation advantage under genotoxic stress condition. In addition, truncated PPM1D promoted tumor growth in the colon in Apc(min) mice and diminished survival. Moreover, tumor organoids derived from colon of the Apc(min)Ppm1d(T/+) mice were less sensitive to 5-fluorouracil when compared to Apc(min)Ppm1d(+/+)and the sensitivity to 5-fluorouracil was restored by inhibition of PPM1D. Finally, we screened colorectal cancer patients and identified recurrent somatic PPM1D mutations in a fraction of colon adenocarcinomas that are p53 proficient and show defects in mismatch DNA repair. In summary, we provide the first in vivo evidence that truncated PPM1D can promote tumor growth and modulate sensitivity to chemotherapy.
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| 4. |
- Danielsen, Stine A, et al.
(författare)
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Methylated RASSF1A in malignant peripheral nerve sheath tumors identifies neurofibromatosis type 1 patients with inferior prognosis.
- 2015
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Ingår i: Neuro-Oncology. - : Oxford University Press (OUP). - 1523-5866 .- 1522-8517. ; 17:1, s. 63-69
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Tidskriftsartikel (refereegranskat)abstract
- Malignant peripheral nerve sheath tumor (MPNST) is a rare and highly aggressive disease with no evidence of effect from adjuvant therapy. It is further associated with the hereditary syndrome neurofibromatosis type 1 (NF1). Silencing of the tumor suppressor gene RASSF1A through DNA promoter hypermethylation is known to be involved in cancer development, but its impact in MPNSTs remains unsettled.
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| 5. |
- Høland, Maren, et al.
(författare)
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Inferior survival for patients with malignant peripheral nerve sheath tumors defined by aberrant TP53
- 2018
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Ingår i: Modern Pathology. - : Elsevier BV. - 0893-3952. ; 31:11, s. 1694-1707
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Tidskriftsartikel (refereegranskat)abstract
- Malignant peripheral nerve sheath tumor is a rare and aggressive disease with poor treatment response, mainly affecting adolescents and young adults. Few molecular biomarkers are used in the management of this cancer type, and although TP53 is one of few recurrently mutated genes in malignant peripheral nerve sheath tumor, the mutation prevalence and the corresponding clinical value of the TP53 network remains unsettled. We present a multi-level molecular study focused on aberrations in the TP53 network in relation to patient outcome in a series of malignant peripheral nerve sheath tumors from 100 patients and 38 neurofibromas, including TP53 sequencing, high-resolution copy number analyses of TP53 and MDM2, and gene expression profiling. Point mutations in TP53 were accompanied by loss of heterozygosity, resulting in complete loss of protein function in 8.2% of the malignant peripheral nerve sheath tumors. Another 5.5% had MDM2 amplification. TP53 mutation and MDM2 amplification were mutually exclusive and patients with either type of aberration in their tumor had a worse prognosis, compared to those without (hazard ratio for 5-year disease-specific survival 3.5, 95% confidence interval 1.78–6.98). Both aberrations had similar consequences on the gene expression level, as analyzed by a TP53-associated gene signature, a property also shared with the copy number aberrations and/or loss of heterozygosity at the TP53 locus, suggesting a common “TP53-mutated phenotype” in as many as 60% of the tumors. This was a poor prognostic phenotype (hazard ratio = 4.1, confidence interval:1.7–9.8), thus revealing a TP53-non-aberrant patient subgroup with a favorable outcome. The frequency of the “TP53-mutated phenotype” warrants explorative studies of stratified treatment strategies in malignant peripheral nerve sheath tumor.
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