| 1. |
- Campbell, PJ, et al.
(författare)
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Pan-cancer analysis of whole genomes
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 578:7793, s. 82-
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Tidskriftsartikel (refereegranskat)abstract
- Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale1–3. Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4–5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter4; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation5,6; analyses timings and patterns of tumour evolution7; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity8,9; and evaluates a range of more-specialized features of cancer genomes8,10–18.
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| 2. |
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| 3. |
- Luen, S J, et al.
(författare)
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Genomic characterisation of hormone receptor-positive breast cancer arising in very young women.
- 2023
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Ingår i: Annals of oncology : official journal of the European Society for Medical Oncology. - : Elsevier BV. - 1569-8041. ; 34:4, s. 397-409
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Tidskriftsartikel (refereegranskat)abstract
- Very young premenopausal women diagnosed with hormone receptor-positive, HER2-negative (HR+HER2-) early breast cancer (EBC) have higher rates of recurrence and death for reasons that remain largely unexplained.Genomic sequencing was applied to HR+HER2- tumours from patients enrolled in the SOFT clinical trial to determine genomic drivers that are enriched in young premenopausal women. Genomic alterations were characterised using next-generation sequencing from a subset of 1,276 patients (deep targeted sequencing, N=1258; whole-exome sequencing in a young-age, case-control subsample, N=82). We defined copy number (CN) subgroups and assessed for features suggestive of homologous recombination deficiency (HRD). Genomic alteration frequencies were compared between young premenopausal women (<40 years) and older premenopausal women (≥40 years), and assessed for associations with distant recurrence-free interval (DRFI), and overall survival (OS).Younger women (<40 years, N=359) compared with older women (≥40 years, N=917) had significantly higher frequencies of mutations in GATA3 (19%vs16%) and CN-amplifications (47%vs26%), but significantly lower frequencies of mutations in PIK3CA (32%vs47%), CDH1 (3%vs9%), and MAP3K1 (7%vs12%). Additionally, significantly higher frequencies of features suggestive of HRD (27%vs21%), and a higher proportion of PIK3CA mutations with concurrent CN-amplifications (23%vs11%).Genomic features suggestive of HRD, PIK3CA mutations with CN-amplifications, and CN-amplifications associated with significantly worse DRFI and OS compared with those without these features. These poor prognostic features were enriched in younger patients: present in 72% of patients aged <35 years, 54% aged 35-39 years, and 40% ≥40 years. Poor prognostic features (N=584[46%]) vs none (N=692[54%]) had an 8-year DRFI of 84%vs94% and OS of 88%vs96%. Younger women (<40) had the poorest outcomes: 8-year DRFI 74%vs85% and OS of 80%vs93% respectively.These results provide insights into genomic alterations that are enriched in young women with HR+HER2-EBC, provide rationale for genomic subgrouping, and highlight priority molecular targets for future clinical trials.
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| 4. |
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| 5. |
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| 6. |
- Nik-Zainal, Serena, et al.
(författare)
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Mutational Processes Molding the Genomes of 21 Breast Cancers
- 2012
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Ingår i: Cell. - : Elsevier BV. - 1097-4172 .- 0092-8674. ; 149:5, s. 979-993
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Tidskriftsartikel (refereegranskat)abstract
- All cancers carry somatic mutations. The patterns of mutation in cancer genomes reflect the DNA damage and repair processes to which cancer cells and their precursors have been exposed. To explore these mechanisms further, we generated catalogs of somatic mutation from 21 breast cancers and applied mathematical methods to extract mutational signatures of the underlying processes. Multiple distinct single- and double-nucleotide substitution signatures were discernible. Cancers with BRCA1 or BRCA2 mutations exhibited a characteristic combination of substitution mutation signatures and a distinctive profile of deletions. Complex relationships between somatic mutation prevalence and transcription were detected. A remarkable phenomenon of localized hypermutation, termed "kataegis,'' was observed. Regions of kataegis differed between cancers but usually colocalized with somatic rearrangements. Base substitutions in these regions were almost exclusively of cytosine at TpC dinucleotides. The mechanisms underlying most of these mutational signatures are unknown. However, a role for the APOBEC family of cytidine deaminases is proposed.
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| 7. |
- Alexandrov, Ludmil B., et al.
(författare)
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Signatures of mutational processes in human cancer
- 2013
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 500:7463, s. 415-421
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Tidskriftsartikel (refereegranskat)abstract
- All cancers are caused by somatic mutations; however, understanding of the biological processes generating these mutations is limited. The catalogue of somatic mutations from a cancer genome bears the signatures of the mutational processes that have been operative. Here we analysed 4,938,362 mutations from 7,042 cancers and extracted more than 20 distinct mutational signatures. Some are present in many cancer types, notably a signature attributed to the APOBEC family of cytidine deaminases, whereas others are confined to a single cancer class. Certain signatures are associated with age of the patient at cancer diagnosis, known mutagenic exposures or defects in DNA maintenance, but many are of cryptic origin. In addition to these genome-wide mutational signatures, hypermutation localized to small genomic regions, 'kataegis', is found in many cancer types. The results reveal the diversity of mutational processes underlying the development of cancer, with potential implications for understanding of cancer aetiology, prevention and therapy.
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| 8. |
- Degasperi, Andrea, et al.
(författare)
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A practical framework and online tool for mutational signature analyses show intertissue variation and driver dependencies
- 2020
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Ingår i: Nature Cancer. - : Springer Science and Business Media LLC. - 2662-1347. ; 1:2, s. 249-263
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Tidskriftsartikel (refereegranskat)abstract
- Mutational signatures are patterns of mutations that arise during tumorigenesis. We present an enhanced, practical framework for mutational signature analyses. Applying these methods to 3,107 whole-genome-sequenced (WGS) primary cancers of 21 organs reveals known signatures and nine previously undescribed rearrangement signatures. We highlight interorgan variability of signatures and present a way of visualizing that diversity, reinforcing our findings in an independent analysis of 3,096 WGS metastatic cancers. Signatures with a high level of genomic instability are dependent on TP53 dysregulation. We illustrate how uncertainty in mutational signature identification and assignment to samples affects tumor classification, reinforcing that using multiple orthogonal mutational signature data is not only beneficial, but is also essential for accurate tumor stratification. Finally, we present a reference web-based tool for cancer and experimentally generated mutational signatures, called Signal (https://signal.mutationalsignatures.com), that also supports performing mutational signature analyses.
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| 9. |
- Ju, Young Seok, et al.
(författare)
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Frequent somatic transfer of mitochondrial DNA into the nuclear genome of human cancer cells.
- 2015
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Ingår i: Genome Research. - : Cold Spring Harbor Laboratory. - 1549-5469 .- 1088-9051. ; 25:6, s. 814-824
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Tidskriftsartikel (refereegranskat)abstract
- Mitochondrial genomes are separated from the nuclear genome for most of the cell cycle by the nuclear double membrane, intervening cytoplasm, and the mitochondrial double membrane. Despite these physical barriers, we show that somatically acquired mitochondrial-nuclear genome fusion sequences are present in cancer cells. Most occur in conjunction with intranuclear genomic rearrangements, and the features of the fusion fragments indicate that nonhomologous end joining and/or replication-dependent DNA double-strand break repair are the dominant mechanisms involved. Remarkably, mitochondrial-nuclear genome fusions occur at a similar rate per base pair of DNA as interchromosomal nuclear rearrangements, indicating the presence of a high frequency of contact between mitochondrial and nuclear DNA in some somatic cells. Transmission of mitochondrial DNA to the nuclear genome occurs in neoplastically transformed cells, but we do not exclude the possibility that some mitochondrial-nuclear DNA fusions observed in cancer occurred years earlier in normal somatic cells.
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| 10. |
- Nik-Zainal, Serena, et al.
(författare)
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The Life History of 21 Breast Cancers
- 2012
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Ingår i: Cell. - : Elsevier BV. - 1097-4172 .- 0092-8674. ; 149:5
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Tidskriftsartikel (refereegranskat)abstract
- Cancer evolves dynamically as clonal expansions supersede one another driven by shifting selective pressures, mutational processes, and disrupted cancer genes. These processes mark the genome, such that a cancer's life history is encrypted in the somatic mutations present. We developed algorithms to decipher this narrative and applied them to 21 breast cancers. Mutational processes evolve across a cancer's lifespan, with many emerging late but contributing extensive genetic variation. Subclonal diversification is prominent, and most mutations are found in just a fraction of tumor cells. Every tumor has a dominant subclonal lineage, representing more than 50% of tumor cells. Minimal expansion of these subclones occurs until many hundreds to thousands of mutations have accumulated, implying the existence of long-lived, quiescent cell lineages capable of substantial proliferation upon acquisition of enabling genomic changes. Expansion of the dominant subclone to an appreciable mass may therefore represent the final rate-limiting step in a breast cancer's development, triggering diagnosis.
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