| 1. |
- Bruun, Jarle, et al.
(författare)
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Regulator of Chromosome Condensation 2 Identifies High-Risk Patients within Both Major Phenotypes of Colorectal Cancer
- 2015
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Ingår i: Clinical Cancer Research. - : AMER ASSOC CANCER RESEARCH. - 1078-0432 .- 1557-3265. ; 21:16, s. 3759-3770
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Colorectal cancer has high incidence and mortality worldwide. Patients with microsatellite instable (MSI) tumors have significantly better prognosis than patients with microsatellite stable (MSS) tumors. Considerable variation in disease outcome remains a challenge within each subgroup, and our purpose was to identify biomarkers that improve prediction of colorectal cancer prognosis. Experimental Design: Mutation analyses of 42 MSI target genes were performed in two independent MSI tumor series (n = 209). Markers that were significantly associated with prognosis in the test series were assessed in the validation series, followed by functional and genetic explorations. The clinical potential was further investigated by immunohistochemistry in a population-based colorectal cancer series (n = 903). Results: We identified the cell-cycle gene regulator of chromosome condensation 2 (RCC2) as a cancer biomarker. We found a mutation in the 50 UTR region of RCC2 that in univariate and multivariate analyses was significantly associated with improved outcome in the MSI group. This mutation caused reduction of protein expression in dual luciferase gene reporter assays. siRNA knockdown in MSI colon cancer cells (HCT15) caused reduced cell proliferation, cell-cycle arrest, and increased apoptosis. Massive parallel sequencing revealed few RCC2 mutations in MSS tumors. However, weak RCC2 protein expression was significantly associated with poor prognosis, independent of clinical highrisk parameters, and stratifies clinically important patient subgroups with MSS tumors, including elderly patients (greater than 75 years), stage II patients, and those with rectal cancer. Conclusions: Impaired RCC2 affects functional and clinical endpoints of colorectal cancer. High-risk patients with either MSI or MSS tumors can be identified with cost-effective routine RCC2 assays. (C) 2015 AACR.
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| 2. |
- 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 .- 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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| 3. |
- 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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| 4. |
- 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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| 5. |
- Kolberg, Matthias, et al.
(författare)
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Protein expression of BIRC5, TK1, and TOP2A in malignant peripheral nerve sheath tumours - A prognostic test after surgical resection.
- 2015
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Ingår i: Molecular Oncology. - : Wiley. - 1574-7891. ; 9:6, s. 1129-1139
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Tidskriftsartikel (refereegranskat)abstract
- No consensus treatment regime exists beyond surgery for malignant peripheral nerve sheath tumours (MPNST), and the purpose of the present study was to find new approaches to stratify patients with good and poor prognosis and to better guide therapeutic intervention for this aggressive soft tissue cancer. From a total of 67 MPNSTs from Scandinavian patients with and without neurofibromatosis type 1, 30 MPNSTs were investigated by genome-wide RNA expression profiling and 63 MPNSTs by immunohistochemical (IHC) analysis, and selected genes were submitted to analyses of disease-specific survival. The potential drug target genes survivin (BIRC5), thymidine kinase 1 (TK1), and topoisomerase 2-alpha (TOP2A), all encoded on chromosome arm 17q, were up-regulated in MPNST as compared to benign neurofibromas. Each of them was found to be independent prognostic markers on the gene expression level, as well as on the protein level. A prognostic profile was identified by combining the nuclear expression scores of the three proteins. For patients with completely resected tumours only 15% in the high risk group were alive after two years, as compared to 78% in the low risk group. In conclusion, we found a novel protein expression profile which identifies MPNST patients with inferior prognosis even after assumed curative surgery. The tested proteins are drug targets; therefore the expression profile may provide predictive information guiding the design of future clinical trials. Importantly, as the effect is seen on the protein level using IHC, the biomarker panel can be readily implemented in routine clinical testing.
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| 6. |
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