| 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. |
- Donia, Marco, et al.
(författare)
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Acquired immune resistance follows complete tumor regression without loss of target antigens or IFNγ signaling
- 2017
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Ingår i: Cancer Research. - 0008-5472. ; 77:17, s. 4562-4566
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Tidskriftsartikel (refereegranskat)abstract
- Cancer immunotherapy can result in durable tumor regressions in some patients. However, patients who initially respond often experience tumor progression. Here, we report mechanistic evidence of tumoral immune escape in an exemplary clinical case: a patient with metastatic melanoma who developed disease recurrence following an initial, unequivocal radiologic complete regression after T-cell–based immunotherapy. Functional cytotoxic T-cell responses, including responses to one mutant neoantigen, were amplified effectively with therapy and generated durable immunologic memory. However, these immune responses, including apparently effective surveillance of the tumor mutanome, did not prevent recurrence. Alterations of the MHC class I antigen-processing and presentation machinery (APM) in resistant cancer cells, but not antigen loss or impaired IFNγ signaling, led to impaired recognition by tumor-specific CD8þ T cells. Our results suggest that future immunotherapy combinations should take into account targeting cancer cells with intact and impaired MHC class I–related APM. Loss of target antigens or impaired IFNγ signaling does not appear to be mandatory for tumor relapse after a complete radiologic regression. Personalized studies to uncover mechanisms leading to disease recurrence within each individual patient are warranted.
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| 4. |
- Fang, Jun, et al.
(författare)
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Functional characterization of a multi-cancer risk locus on chr5p15.33 reveals regulation of TERT by ZNF148
- 2017
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Genome wide association studies (GWAS) have mapped multiple independent cancer susceptibility loci to chr5p15.33. Here, we show that fine-mapping of pancreatic and testicular cancer GWAS within one of these loci (Region 2 in CLPTM1L) focuses the signal to nine highly correlated SNPs. Of these, rs36115365-C associated with increased pancreatic and testicular but decreased lung cancer and melanoma risk, and exhibited preferred protein-binding and enhanced regulatory activity. Transcriptional gene silencing of this regulatory element repressed TERT expression in an allele-specific manner. Proteomic analysis identifies allele-preferred binding of Zinc finger protein 148 (ZNF148) to rs36115365-C, further supported by binding of purified recombinant ZNF148. Knockdown of ZNF148 results in reduced TERT expression, telomerase activity and telomere length. Our results indicate that the association with chr5p15.33-Region 2 may be explained by rs36115365, a variant influencing TERT expression via ZNF148 in a manner consistent with elevated TERT in carriers of the C allele.
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| 5. |
- 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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| 6. |
- Harbst, Katja, et al.
(författare)
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The genetic evolution of melanoma
- 2018
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Ingår i: Melanoma : A Modern Multidisciplinary Approach - A Modern Multidisciplinary Approach. - Cham : Springer International Publishing. - 9783319783093 - 9783319783109 ; , s. 105-114
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Bokkapitel (refereegranskat)abstract
- Melanoma tumors are driven by a hyperactivated mitogen-activated protein kinase (MAPK) signalling pathway, and therefore can generally be classified by mutations within the B-Raf proto-oncogene (BRAF), RAS family of proto-oncogenes, neurofibromin 1 (NF1), or other genes. At the transcriptional level, several genetic classifications of melanoma have converged on the distinction between melanogenesis (previously microphthalmia) associated transcription factor (MITF)-low and MITF-high phenotypes and expression of immune-related genes. Mutation-based melanoma subtypes are not prognostic, nor are they associated to transcriptomic subtypes, which are in turn prognostic. Intratumoral heterogeneity of melanoma cells adds another layer of complexity, with recent findings of mutational and transcriptional heterogeneity within melanoma tumors. Furthermore, multiple genetic changes have been associated with different stages of melanoma progression. Mutational signatures may also be differentiated at early and late stages of melanoma progression.
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| 7. |
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| 8. |
- 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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| 9. |
- Lauss, Martin, et al.
(författare)
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Mutational and putative neoantigen load predict clinical benefit of adoptive T cell therapy in melanoma
- 2017
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Adoptive T-cell therapy (ACT) is a highly intensive immunotherapy regime that has yielded remarkable response rates and many durable responses in clinical trials in melanoma; however, 50-60% of the patients have no clinical benefit. Here, we searched for predictive biomarkers to ACT in melanoma. Whole exome-and transcriptome sequencing and neoantigen prediction were applied to pre-treatment samples from 27 patients recruited to a clinical phase I/II trial of ACT in stage IV melanoma. All patients had previously progressed on other immunotherapies. We report that clinical benefit is associated with significantly higher predicted neoantigen load. High mutation and predicted neoantigen load are significantly associated with improved progression-free and overall survival. Further, clinical benefit is associated with the expression of immune activation signatures including a high MHC-I antigen processing and presentation score. These results improve our understanding of mechanisms behind clinical benefit of ACT in melanoma.
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| 10. |
- Phung, Bengt, et al.
(författare)
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The X-Linked DDX3X RNA Helicase Dictates Translation Reprogramming and Metastasis in Melanoma
- 2019
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 27:12, s. 7-3586
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Tidskriftsartikel (refereegranskat)abstract
- The X-linked DDX3X gene encodes an ATP-dependent DEAD-box RNA helicase frequently altered in various human cancers, including melanomas. Despite its important roles in translation and splicing, how DDX3X dysfunction specifically rewires gene expression in melanoma remains completely unknown. Here, we uncover a DDX3X-driven post-transcriptional program that dictates melanoma phenotype and poor disease prognosis. Through an unbiased analysis of translating ribosomes, we identified the microphthalmia-associated transcription factor, MITF, as a key DDX3X translational target that directs a proliferative-to-metastatic phenotypic switch in melanoma cells. Mechanistically, DDX3X controls MITF mRNA translation via an internal ribosome entry site (IRES) embedded within the 5' UTR. Through this exquisite translation-based regulatory mechanism, DDX3X steers MITF protein levels dictating melanoma metastatic potential in vivo and response to targeted therapy. Together, these findings unravel a post-transcriptional layer of gene regulation that may provide a unique therapeutic vulnerability in aggressive male melanomas.
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