| 1. |
- Cirenajwis, Helena, et al.
(författare)
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Molecular stratification of metastatic melanoma using gene expression profiling: prediction of survival outcome and benefit from molecular targeted therapy.
- 2015
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 6:14, s. 12297-12309
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Tidskriftsartikel (refereegranskat)abstract
- Melanoma is currently divided on a genetic level according to mutational status. However, this classification does not optimally predict prognosis. In prior studies, we have defined gene expression phenotypes (high-immune, pigmentation, proliferative and normal-like), which are predictive of survival outcome as well as informative of biology. Herein, we employed a population-based metastatic melanoma cohort and external cohorts to determine the prognostic and predictive significance of the gene expression phenotypes. We performed expression profiling on 214 cutaneous melanoma tumors and found an increased risk of developing distant metastases in the pigmentation (HR, 1.9; 95% CI, 1.05-3.28; P=0.03) and proliferative (HR, 2.8; 95% CI, 1.43-5.57; P=0.003) groups as compared to the high-immune response group. Further genetic characterization of melanomas using targeted deep-sequencing revealed similar mutational patterns across these phenotypes. We also used publicly available expression profiling data from melanoma patients treated with targeted or vaccine therapy in order to determine if our signatures predicted therapeutic response. In patients receiving targeted therapy, melanomas resistant to targeted therapy were enriched in the MITF-low proliferative subtype as compared to pre-treatment biopsies (P=0.02). In summary, the melanoma gene expression phenotypes are highly predictive of survival outcome and can further help to discriminate patients responding to targeted therapy.
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| 2. |
- Cirenajwis, Helena, et al.
(författare)
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NF1-mutated melanoma tumors harbor distinct clinical and biological characteristics
- 2017
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Ingår i: Molecular Oncology. - : Wiley. - 1574-7891. ; 11:4, s. 438-451
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Tidskriftsartikel (refereegranskat)abstract
- In general, melanoma can be considered as a UV-driven disease with an aggressive metastatic course and high mutational load, with only few tumors (acral, mucosal, and uveal melanomas) not induced by sunlight and possessing a lower mutational load. The most commonly activated pathway in melanoma is the mitogen-activated protein kinase (MAPK) pathway. However, the prognostic significance of mutational stratification is unclear and needs further investigation. Here, in silico we combined mutation data from 162 melanomas subjected to targeted deep sequencing with mutation data from three published studies. Tumors from 870 patients were grouped according to BRAF, RAS, NF1 mutation or triple-wild-type status and correlated with tumor and patient characteristics. We found that the NF1-mutated subtype had a higher mutational burden and strongest UV mutation signature. Searching for co-occurring mutated genes revealed the RASopathy genes PTPN11 and RASA2, as well as another RAS domain-containing gene RASSF2 enriched in the NF1 subtype after adjustment for mutational burden. We found that a larger proportion of the NF1-mutant tumors were from males and with older age at diagnosis. Importantly, we found an increased risk of death from melanoma (disease-specific survival, DSS; HR, 1.9; 95% CI, 1.21-3.10; P = 0.046) and poor overall survival (OS; HR, 2.0; 95% CI, 1.28-2.98; P = 0.01) in the NF1 subtype, which remained significant after adjustment for age, gender, and lesion type (DSS P = 0.03, OS P = 0.06, respectively). Melanoma genomic subtypes display different biological and clinical characteristics. The poor outcome observed in the NF1 subtype highlights the need for improved characterization of this group.
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| 3. |
- Harbst, Katja, et al.
(författare)
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Molecular and genetic diversity in the metastatic process of melanoma.
- 2014
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Ingår i: Journal of Pathology. - : Wiley. - 0022-3417 .- 1096-9896. ; 233:1, s. 39-50
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Tidskriftsartikel (refereegranskat)abstract
- Diversity between metastatic melanoma tumours in individual patients is known; however, the molecular and genetic differences remain unclear. To examine the molecular and genetic differences between metastatic tumours, we performed gene-expression profiling of 63 melanoma tumours obtained from 28 patients (two or three tumours/patient), followed by analysis of their mutational landscape, using targeted deep sequencing of 1697 cancer genes and DNA copy number analysis. Gene-expression signatures revealed discordant phenotypes between tumour lesions within a patient in 50% of the cases. In 18 of 22 patients (where matched normal tissue was available), we found that the multiple lesions within a patient were genetically divergent, with one or more melanoma tumours harbouring 'private' somatic mutations. In one case, the distant subcutaneous metastasis of one patient occurring 3 months after an earlier regional lymph node metastasis had acquired 37 new coding sequence mutations, including mutations in PTEN and CDH1. However, BRAF and NRAS mutations, when present in the first metastasis, were always preserved in subsequent metastases. The patterns of nucleotide substitutions found in this study indicate an influence of UV radiation but possibly also DNA alkylating agents. Our results clearly demonstrate that metastatic melanoma is a molecularly highly heterogeneous disease that continues to progress throughout its clinical course. The private aberrations observed on a background of shared aberrations within a patient provide evidence of continued evolution of individual tumours following divergence from a common parental clone, and might have implications for personalized medicine strategies in melanoma treatment. Published by John Wiley & Sons, Ltd. www.pathsoc.org.uk.
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| 4. |
- Harbst, Katja, et al.
(författare)
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Molecular profiling reveals low- and high-grade forms of primary melanoma.
- 2012
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Ingår i: Clinical cancer research : an official journal of the American Association for Cancer Research. - 1557-3265. ; 18:15, s. 4026-4036
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Tidskriftsartikel (refereegranskat)abstract
- For primary melanomas, tumor thickness, mitotic rate, and ulceration are well-laid cornerstones of prognostication. However, a molecular exposition of melanoma aggressiveness is critically missing. We recently uncovered a four-class structure in metastatic melanoma, which predicts outcome and informs biology. This raises the possibility that a molecular structure exists even in the early stages of melanoma and that molecular determinants could underlie histophenotype and eventual patient outcome.We subjected 223 archival primary melanomas to a horizontally integrated analysis of RNA expression, oncogenic mutations at 238 lesions, histomorphometry, and survival data.Our previously described four-class structure that was elucidated in metastatic lesions was evident within the expression space of primary melanomas. Because these subclasses converged into two larger prognostic and phenotypic groups, we used the metastatic lesions to develop a binary subtype-based signature capable of distinguishing between "high" and "low" grade forms of the disease. The two-grade signature was subsequently applied to the primary melanomas. Compared with low-grade tumors, high-grade primary melanomas were significantly associated with increased tumor thickness, mitotic rate, ulceration (all P < 0.01), and poorer relapse-free (HR = 4.94; 95% CI, 2.84-8.59), and overall (HR = 3.66; 95% CI, 2.40-5.58) survival. High-grade melanomas exhibited elevated levels of proliferation and BRCA1/DNA damage signaling genes, whereas low-grade lesions harbored higher expression of immune genes. Importantly, the molecular-grade signature was validated in two external gene expression data sets.We provide evidence for a molecular organization within melanomas, which is preserved across all stages of disease.
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| 5. |
- Harbst, Katja, et al.
(författare)
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Multiple metastases from cutaneous malignant melanoma patients may display heterogeneous genomic and epigenomic patterns.
- 2010
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Ingår i: Melanoma Research. - 0960-8931. ; 20:5, s. 381-391
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Tidskriftsartikel (refereegranskat)abstract
- Disseminated melanoma is an aggressive disease with fatal outcome. Better understanding of the underlying biology is needed to find effective treatment. We applied microarray-based comparative genomic hybridization, gene expression and CpG island methylation analysis of primary tumors and multiple metastases from five melanoma patients with the aim of analyzing the molecular patterns of melanoma progression. Epigenetic profiling showed that the multiple metastases after a single primary melanoma share similar methylation patterns for many genes, although differences in methylation between the lesions were evident for several genes, example, PTEN, TFAP2C, and RARB. In addition, DNA copy number and global gene expression profiles of tumors from individual patients were highly similar, confirming common origin of metastases. Some of the identified genomic aberrations, for example, gain of chromosome 6p and loss of chromosomes 6q and 10, persisted during progression, indicating early changes highly important for melanoma development. Homozygous deletions at 3p26.1 and 6q23.2-q23.3 appeared in two consecutive metastases originating from the same primary tumor, respectively, in a mutually exclusive manner that provides evidence for two genetically different subclones. However, in another case, the similarity of the copy number aberrations in subsequent metastatic lesions suggests sequential metastatic development through the clonal evolution. These data are further corroborated by a switch in CDH1 and CDH2 expression between metastases from the same patient. In conclusion, our results provide evidence for different models of metastatic progression in melanoma.
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| 6. |
- Harbst, Katja, et al.
(författare)
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Multiregion whole-exome sequencing uncovers the genetic evolution and mutational heterogeneity of early-stage metastatic melanoma
- 2016
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Ingår i: Cancer Research. - 0008-5472. ; 76:16, s. 4765-4774
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Tidskriftsartikel (refereegranskat)abstract
- Cancer genome sequencing has shed light on the underlying genetic aberrations that drive tumorigenesis. However, current sequencing-based strategies, which focus on a single tumor biopsy, fail to take into account intratumoral heterogeneity. To address this challenge and elucidate the evolutionary history of melanoma, we performed whole-exome and transcriptome sequencing of 41 multiple melanoma biopsies from eight individual tumors. This approach revealed heterogeneous somatic mutations in the range of 3%-38% in individual tumors. Known mutations in melanoma drivers BRAF and NRAS were always ubiquitous events. Using RNA sequencing, we found that the majority of mutations were not expressed or were expressed at very low levels, and preferential expression of a particular mutated allele did not occur frequently. In addition, we found that the proportion of ultraviolet B (UVB) radiation-induced C>T transitions differed significantly (P <0.001) between early and late mutation acquisition, suggesting that different mutational processes operate during the evolution of metastatic melanoma. Finally, clinical history reports revealed that patients harboring a high degree of mutational heterogeneity were associated with more aggressive disease progression. In conclusion, our multiregion tumor-sequencing approach highlights the genetic evolution and non-UVB mutational signatures associated with melanoma development and progression, and may provide a more comprehensive perspective of patient outcome.
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| 7. |
- Jönsson, Jenny-Maria, et al.
(författare)
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Distinct gene expression profiles in ovarian cancer linked to Lynch syndrome.
- 2014
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Ingår i: Familial Cancer. - : Springer Science and Business Media LLC. - 1389-9600 .- 1573-7292. ; 13:4, s. 537-545
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Tidskriftsartikel (refereegranskat)abstract
- Ovarian cancer linked to Lynch syndrome represents a rare subset that typically presents at young age as early-stage tumors with an overrepresentation of endometrioid and clear cell histologies. We investigated the molecular profiles of Lynch syndrome-associated and sporadic ovarian cancer with the aim to identify key discriminators and central tumorigenic mechanisms in hereditary ovarian cancer. Global gene expression profiling using whole-genome c-DNA-mediated Annealing, Selection, extension, and Ligation was applied to 48 histopathologically matched Lynch syndrome-associated and sporadic ovarian cancers. Lynch syndrome-associated and sporadic ovarian cancers differed by 349 significantly deregulated genes, including PTPRH, BIRC3, SHH and TNFRSF6B. The genes involved were predominantly linked to cell growth, proliferation, and cell-to-cell signaling and interaction. When stratified for histologic subtype, hierarchical clustering confirmed distinct differences related to heredity in the endometrioid and serous subtypes. Furthermore, separate clustering was achieved in an independent, publically available data set. The distinct genetic signatures in Lynch syndrome-associated and sporadic ovarian cancers point to alternative preferred tumorigenic routes and suggest that genetic discriminators may be relevant for molecular diagnostics and targeted therapeutics.
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| 8. |
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| 9. |
- Lauss, Martin, et al.
(författare)
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Genome-Wide DNA Methylation Analysis in Melanoma Reveals the Importance of CpG Methylation in MITF Regulation.
- 2015
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 1523-1747 .- 0022-202X. ; 135:7, s. 1820-1828
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Tidskriftsartikel (refereegranskat)abstract
- The microphthalmia-associated transcription factor (MITF) is a key regulator of melanocyte development and a lineage-specific oncogene in melanoma; a highly lethal cancer known for its unpredictable clinical course. MITF is regulated by multiple intracellular signaling pathways although the exact mechanisms that determine MITF expression and activity remain incompletely understood. In this study, we obtained genome-wide DNA methylation profiles from 50 stage IV melanomas, normal melanocytes, keratinocytes and dermal fibroblasts, and utilized The Cancer Genome Atlas (TCGA) data for experimental validation. By integrating DNA methylation and gene expression data we found that hypermethylation of MITF and its co-regulated differentiation pathway genes, corresponded to decreased gene expression levels. In cell lines with a hypermethylated MITF-pathway, over-expression of MITF did not alter the expression level or methylation status of the MITF pathway genes. In contrast however, demethylation treatment of these cell lines induced MITF-pathway activity, confirming that gene-regulation was controlled via methylation. The discovery that the activity of the master regulator of pigmentation, MITF, and its downstream targets may be regulated by hypermethylation has significant implications for understanding the development and evolvement of melanoma.Journal of Investigative Dermatology accepted article preview online, 23 February 2015. doi:10.1038/jid.2015.61.
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| 10. |
- Nielsen, Kari, et al.
(författare)
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Swedish CDKN2A mutation carriers do not present the atypical mole syndrome phenotype.
- 2010
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Ingår i: Melanoma Research. - 0960-8931. ; Jul 1, s. 266-272
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Tidskriftsartikel (refereegranskat)abstract
- Phenotypic characteristics were examined in melanoma-prone southern Swedish CDKN2A (p16-113insArg/p14ARF-128insSer) mutation families, in relation to the CDKN2A genotype, nevi, clinically atypical nevi (CAN) and melanoma. Individuals from eight melanoma-prone families, with index patients carrying the CDKN2A mutation, were offered skin examinations and genotyping (CDKN2A and MC1R). Ninety-three individuals above 18 years of age participated; 29 invasive melanomas in 16 patients were recorded, all in the 38 verified CDKN2A mutation carriers. Median age at diagnosis was 36 years. Several MC1R variants were observed. A significant correlation to CAN (P=0.01) and red hair colour (P=0.02) could be confirmed in melanoma patients. A positive mutation status (CDKN2A) was correlated to one or more CAN (P=0.007) but neither to blue eyes, red hair colour, heavy freckling nor high number of nevi. For mutation carriers, median total naevus count was 24 and interquartile range was 12-47 (mean 31); whereas for the whole cohort, median total naevus count was 12 and interquartile range was 5-25 (mean 22). No participant fulfilled the atypical mole syndrome phenotype criteria. Melanomas were diagnosed only in mutation carriers, and melanoma diagnosis was statistically correlated to the presence of one or more CAN and red hair colour, supporting the possible synergistic effect of a MC1R mutation on increased risk of melanoma in patients with a CDKN2A mutation. Family history, with verified tumour diagnoses, remains an important clinical tool for finding mutation carriers for referral to clinical geneticists and simultaneous presence of CAN in probable mutation carriers might strengthen this indication. The atypical mole syndrome phenotype was, however, not verified in the studied families and total naevus counts were low.
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