| 1. |
- Kiflemariam, Sara, et al.
(author)
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In situ sequencing identifies TMPRSS2-ERG fusion transcripts, somatic point mutations and gene expression levels in prostate cancers
- 2014
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In: Journal of Pathology. - : Wiley. - 0022-3417 .- 1096-9896. ; 234:2, s. 253-261
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Journal article (peer-reviewed)abstract
- Translocations contribute to the genesis and progression of epithelial tumours and in particular to prostate cancer development. To better understand the contribution of fusion transcripts and visualize the clonal composition of multifocal tumours, we have developed a technology for multiplex in situ detection and identification of expressed fusion transcripts. When compared to immunohistochemistry, TMPRSS2-ERG fusion-negative and fusion-positive prostate tumours were correctly classified. The most prevalent TMPRSS2-ERG fusion variants were visualized, identified, and quantitated in human prostate cancer tissues, and the ratio of the variant fusion transcripts could for the first time be directly determined by in situ sequencing. Further, we demonstrate concurrent in situ detection of gene expression, point mutations, and gene fusions of the prostate cancer relevant targets AMACR, AR, TP53, and TMPRSS2-ERG. This unified approach to in situ analyses of somatic mutations can empower studies of intra-tumoural heterogeneity and future tissue-based diagnostics of mutations and translocations.
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| 2. |
- Mignardi, Marco, et al.
(author)
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Fourth-generation sequencing in the cell and the clinic
- 2014
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In: Genome Medicine. - : Springer Science and Business Media LLC. - 1756-994X .- 1756-994X. ; 6, s. 31-31
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Journal article (other academic/artistic)abstract
- Nearly 40 years ago, DNA was sequenced for the first time. Since then, DNA sequencing has undergone continuous development, passing through three generations of sequencing technology. We are now entering the beginning of a new phase of genomic analysis in which massively parallel sequencing is performed directly in the cell. Two methods have recently been described for in situ RNA sequencing, one targeted and one untargeted, that rely on ligation chemistry. This fourth generation of sequencing technology opens up prospects for transcriptomic analysis, biomarker validation, diagnosis and patient stratification for cancer treatment.
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| 3. |
- Mignardi, Marco, 1981-
(author)
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In situ Sequencing : Methods for spatially-resolved transcriptome analysis
- 2014
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Doctoral thesis (other academic/artistic)abstract
- It is well known that cells in tissues display a large heterogeneity in gene expression due to differences in cell lineage origin and variation in the local environment at different sites in the tissue, a heterogeneity that is difficult to study by analyzing bulk RNA extracts from tissue. Recently, genome-wide transcriptome analysis technologies have enabled the analysis of this variation with single-cell resolution. In order to link the heterogeneity observed at molecular level with the morphological context of tissues, new methods are needed which achieve an additional level of information, such as spatial resolution.In this thesis I describe the development and application of padlock probes and rolling circle amplification (RCA) as molecular tools for spatially-resolved transcriptome analysis. Padlock probes allow in situ detection of individual mRNA molecules with single nucleotide resolution, visualizing the molecular information directly in the cell and tissue context. Detection of clinically relevant point mutations in tumor samples is achieved by using padlock probes in situ, allowing visualization of intra-tumor heterogeneity. To resolve more complex gene expression patterns, we developed in situ sequencing of RCA products combining padlock probes and next-generation sequencing methods. We demonstrated the use of this new method by, for the first time, sequencing short stretches of transcript molecules directly in cells and tissue. By using in situ sequencing as read-out for multiplexed padlock probe assays, we measured the expression of tens of genes in hundreds of thousands of cells, including point mutations, fusions transcripts and gene expression level.These molecular tools can complement genome-wide transcriptome analyses adding spatial resolution to the molecular information. This level of resolution is important for the understanding of many biological processes and potentially relevant for the clinical management of cancer patients.
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