8fc6a85b-80a4-4510-916e-1014ed168795 - samples
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ABSTRACT:
PROVIDER: EGAD00001005196 | EGA |
REPOSITORIES: EGA
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Project description:Purpose: Inflammatory bowel disease-associated colorectal cancers (IBD-CRC) are associated with a higher mortality than sporadic colorectal cancers. The poorly defined molecular pathogenesis of IBD-CRCs limits development of effective prevention, detection, and treatment strategies. We aimed to identify biomarkers using whole-exome sequencing of IBD-CRCs to guide individualized management.Experimental Design: Whole-exome sequencing was performed on 34 formalin-fixed paraffin-embedded primary IBD-CRCs and 31 matched normal lymph nodes. Computational methods were used to identify somatic point mutations, small insertions and deletions, mutational signatures, and somatic copy number alterations. Mismatch repair status was examined.Results: Hypermutation was observed in 27% of IBD-CRCs. All hypermutated cancers were from the proximal colon; all but one of the cancers with hypermutation had defective mismatch repair or somatic mutations in the proofreading domain of DNA POLE Hypermutated IBD-CRCs had increased numbers of predicted neo-epitopes, which could be exploited using immunotherapy. We identified six distinct mutation signatures in IBD-CRCs, three of which corresponded to known mechanisms of mutagenesis. Driver genes were also identified.Conclusions: IBD-CRCs should be evaluated for hypermutation and defective mismatch repair to identify patients with a higher neo-epitope load who may benefit from immunotherapies. Prospective trials are required to determine whether IHC to detect loss of MLH1 expression in dysplastic colonic tissue could identify patients at increased risk of developing IBD-CRC. We identified mutations in genes in IBD-CRCs with hypermutation that might be targeted therapeutically. These approaches would complement and individualize surveillance and treatment programs. Clin Cancer Res; 24(20); 5133-42. ©2018 AACR.
| S-EPMC6193541 | BioStudies
Project description:The requirement for large amounts of good quality DNA for whole-genome applications prohibits their use for small, laser capture micro-dissected (LCM), and/or rare clinical samples, which are also often formalin-fixed and paraffin-embedded (FFPE). Whole-genome amplification of DNA from these samples could, potentially, overcome these limitations. However, little is known about the artefacts introduced by amplification of FFPE-derived DNA with regard to genotyping, and subsequent copy number and loss of heterozygosity (LOH) analyses. Using a ligation adaptor amplification method, we present data from a total of 22 Affymetrix SNP 6.0 experiments, using matched paired amplified and non-amplified DNA from 10 LCM FFPE normal and dysplastic oral epithelial tissues, and an internal method control. An average of 76.5% of SNPs were called in both matched amplified and non-amplified DNA samples, and concordance was a promising 82.4%. Paired analysis for copy number, LOH, and both combined, showed that copy number changes were reduced in amplified DNA, but were 99.5% concordant when detected, amplifications were the changes most likely to be 'missed', only 30% of non-amplified LOH changes were identified in amplified pairs, and when copy number and LOH are combined ?50% of gene changes detected in the unamplified DNA were also detected in the amplified DNA and within these changes, 86.5% were concordant for both copy number and LOH status. However, there are also changes introduced as ?20% of changes in the amplified DNA are not detected in the non-amplified DNA. An integrative network biology approach revealed that changes in amplified DNA of dysplastic oral epithelium localize to topologically critical regions of the human protein-protein interaction network, suggesting their functional implication in the pathobiology of this disease. Taken together, our results support the use of amplification of FFPE-derived DNA, provided sufficient samples are used to increase power and compensate for increased error rates.
| S-EPMC3180289 | BioStudies
Project description:The goal of this experiment is to characterize the copy number changes in esophageal mucosa of patients with Barrett's esophagus (BE) who progress to esophageal dysplasia and adenocarcinoma (BE progressors), as compared to patients with BE who do not progress for at least two years after esophageal mucosal sampling (non-progressors with never dysplastic Barrett's esophagus - NvDBE - samples). We sampled esophageal mucosa from the following groups: 1) non-dysplastic intestinal metaplasia from 16 patients at least 1 year before progression to esophageal dysplasia or adenocarcinoma (PP-BE); 2) non-dysplastic intestinal metaplasia from 21 patients who did not progress to dysplasia or adenocarcinoma for at least 2 years of surveillance after the tested sample (NvDBE) 3) non-dysplastic intestinal metaplasia from 21 patients who had temporally concurrent but spatially separate intestinal metaplasia samples from the same procedure (C-BE). 4) 10 samples of esophageal dysplasia or adenocarcinoma from patients in group 1 and 3. Samples were obtained by endoscopic biopsy, endomucosal resection or surgical resection, processed for clinical purposes by routine histopathologic methods, including formalin fixation and paraffin embedding (FFPE). DNA was extracted from 5 micro tissue sections of FFPE blocks and DNA extracted using QIAamp DNA FFPE Tissue Kit (Qiagen, Germantown, MD). Samples were processed for identification of somatic copy number alterations using the OncoScan FFPE Assay or the OncoScan CNV Assay (Affymetrix, Santa Clara, CA) according to the manufacturer's protocols. After hybridization, the arrays were washed, stained using GeneChip Fluidics Station 450 (Affymetrix) and scanned using GeneChip Scanner 3000 7G (Affymetrix). The CEL files generated are deposited here.
| E-MTAB-7396 | BioStudies
Project description:We investigated a cohort of 34 archival cutaneous melanoma samples by Agilent 40 kb-resolution CGH array. We found a non-random distribution of precise CNAs predictive for clinical outcome. Although most of the alterations defined in this study have been already reported, we mapped novel melanoma-specific CNAs at highest accuracy. Moreover, our data revealed distinct amplifications hotspots, some of which were validated by quantitative real-time PCR, enabling the identification of novel melanoma oncogenic candidates. Keywords: Cutaneous melanoma, Copy number alterations, Biomarkers, FFPE We examined 34 primary melanoma formalin-fixed and paraffin-embedded (FFPE) samples by using array comparative genomic hybridization (aCGH) for DNA copy number alterations (CNAs). Genomic DNA was extracted, referred to a sex-matched diploid commercial control DNA (Promega Corporation, Madison, WI, cat. G1417 and G1521), and hybridized on the Agilent SurePrint G3 Human CGH Microarray 8x60k, cat. G4827A.
| E-GEOD-45354 | BioStudies
Project description:Analysis of DNA from 89 oral lesions by whole genome tiling-path array comparative genomic hybridization. Keywords: array comparative genomic hybridization Genomic DNA isolated from 89 formalin-fixed paraffin-embedded oral dysplasias and tumors, then profiled by whole genome tiling-path array CGH to identify DNA copy alterations for each case.
| E-GEOD-11275 | BioStudies
Project description:Advanced cancer genomics technologies are now being employed in clinical sequencing, where next-generation sequencers are used to simultaneously identify multiple types of DNA alterations for prescription of molecularly targeted drugs. However, no computational tool is available to accurately detect DNA alterations in formalin-fixed paraffin-embedded (FFPE) samples commonly used in hospitals. Here, we developed a computational tool tailored to the detection of single nucleotide variations, indels, fusions, and copy number alterations in FFPE samples. Elaborated multilayer noise filters reduced the inherent noise while maintaining high sensitivity, as evaluated in tumor-unmatched normal samples using orthogonal technologies. This tool, cisCall, should facilitate clinical sequencing in everyday diagnostics. It is available at https://www.ciscall.org .
| S-EPMC5992758 | BioStudies
Project description:Small-cell lung cancer (SCLC) is the most aggressive subtype of lung cancer in its clinical behavior, with a 5-year overall survival as low as 5%. Despite years of research in the field, molecular determinants of SCLC behavior are still poorly understood, and this deficiency has translated into an absence of specific diagnostics and targeted therapeutics. We hypothesized that tumor DNA copy number alterations would allow the identification of molecular pathways involved in SCLC progression. Array comparative genomic hybridization was performed on DNA extracted from 46 formalin-fixed paraffin-embedded SCLC tissue specimens. Genomic profiling of tumor and sex-matched control DNA allowed the identification of 70 regions of copy number gain and 55 regions of copy number loss. Using molecular pathway analysis, we found a strong enrichment in these regions of copy number alterations for 11 genes associated with the focal adhesion pathway. We verified these findings at the genomic, gene expression and protein level. Focal Adhesion Kinase (FAK), one of the central genes represented in this pathway, was commonly expressed in SCLC tumors and constitutively phosphorylated in SCLC cell lines. Those were poorly adherent to most substrates but not to laminin-322. Inhibition of FAK phosphorylation at Tyr(397) by a small-molecule inhibitor, PF-573,228, induced a dose-dependent decrease of adhesion and an increase of spreading in SCLC cell lines on laminin-322. Cells that tended to spread also showed a decrease in focal adhesions, as demonstrated by a decreased vinculin expression. These results support the concept that pathway analysis of genes in regions of copy number alterations may uncover molecular mechanisms of disease progression and demonstrate a new role of FAK and associated adhesion pathways in SCLC. Further investigations of FAK at the functional level may lead to a better understanding of SCLC progression and may have therapeutic implications.
| S-EPMC4637980 | BioStudies
Project description:We have carried out microarray-based comparative genomic hybridisation (arrayCGH) on 50 perilobar nephrogenic rest and 25 matching Wilms tumours in order to identify changes in DNA copy number associated with IGF-driven Wilms tumorigenesis. All patient samples were formalin fixed-paraffin embedded archival material. Tumour DNA was co-hybridised with normal female genomic DNA onto 5.8K, 0.9Mb-spaced (E-MEXP-213) and/or a 16K, 100kb-spaced BAC array. Data was normalised and quality-filtered, an adapted weights smoothing algorithm fitted, and changes in DNA copy number assessed for each clone.
| E-TABM-436 | BioStudies
Project description:<h4>Objective</h4>IBD confers an increased lifetime risk of developing colorectal cancer (CRC), and colitis-associated CRC (CA-CRC) is molecularly distinct from sporadic CRC (S-CRC). Here we have dissected the evolutionary history of CA-CRC using multiregion sequencing.<h4>Design</h4>Exome sequencing was performed on fresh-frozen multiple regions of carcinoma, adjacent non-cancerous mucosa and blood from 12 patients with CA-CRC (n=55 exomes), and key variants were validated with orthogonal methods. Genome-wide copy number profiling was performed using single nucleotide polymorphism arrays and low-pass whole genome sequencing on archival non-dysplastic mucosa (n=9), low-grade dysplasia (LGD; n=30), high-grade dysplasia (HGD; n=13), mixed LGD/HGD (n=7) and CA-CRC (n=19). Phylogenetic trees were reconstructed, and evolutionary analysis used to reveal the temporal sequence of events leading to CA-CRC.<h4>Results</h4>10/12 tumours were microsatellite stable with a median mutation burden of 3.0 single nucleotide alterations (SNA) per Mb, ~20%?higher than S-CRC (2.5 SNAs/Mb), and consistent with elevated ageing-associated mutational processes. Non-dysplastic mucosa had considerable mutation burden (median 47 SNAs), including mutations shared with the neighbouring CA-CRC, indicating a precancer mutational field. CA-CRCs were often near triploid (40%) or near tetraploid (20%) and phylogenetic analysis revealed that copy number alterations (CNAs) began to accrue in non-dysplastic bowel, but the LGD/HGD transition often involved a punctuated 'catastrophic' CNA increase.<h4>Conclusions</h4>Evolutionary genomic analysis revealed precancer clones bearing extensive SNAs and CNAs, with progression to cancer involving a dramatic accrual of CNAs at HGD. Detection of the cancerised field is an encouraging prospect for surveillance, but punctuated evolution may limit the window for early detection.
| S-EPMC6580738 | BioStudies
Project description:As more clinically relevant cancer genes are identified, comprehensive diagnostic approaches are needed to match patients to therapies, raising the challenge of optimization and analytical validation of assays that interrogate millions of bases of cancer genomes altered by multiple mechanisms. Here we describe a test based on massively parallel DNA sequencing to characterize base substitutions, short insertions and deletions (indels), copy number alterations and selected fusions across 287 cancer-related genes from routine formalin-fixed and paraffin-embedded (FFPE) clinical specimens. We implemented a practical validation strategy with reference samples of pooled cell lines that model key determinants of accuracy, including mutant allele frequency, indel length and amplitude of copy change. Test sensitivity achieved was 95-99% across alteration types, with high specificity (positive predictive value >99%). We confirmed accuracy using 249 FFPE cancer specimens characterized by established assays. Application of the test to 2,221 clinical cases revealed clinically actionable alterations in 76% of tumors, three times the number of actionable alterations detected by current diagnostic tests.
| S-EPMC5710001 | BioStudies