Low-coverage whole genome sequencing of FFPE-derived-DNA and extracellular vesicle-associated DNA in patients with metastatic cancer.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e14523-e14523
Author(s):  
Bella Hai Nguyen ◽  
Nick Wong ◽  
Timothy Semple ◽  
Olivia Ruhen ◽  
Stephen Q Wong ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Metastatic Cancer ◽  
Valuable Insight ◽  
Whole Genome ◽  
Plasma Dna ◽  
Primary Tumors ◽  
Hpv Status ◽  
Ffpe Samples ◽  
Low Coverage

e14523 Background: Low-coverage whole genome sequencing (LC-WGS) of tumors provides valuable insight into molecular changes driving oncogenesis. A novel liquid biopsy source of tumor DNA for analysis is from extracellular vesicles (EV) obtained from blood. This study compared copy number alteration (CNA) profiles generated from LC-WGS of Formalin-Fixed Paraffin-Embedded (FFPE) DNA and EV-associated DNA in cancer patients. Methods: Three metastatic base of tongue (BOT), two of which were Human Papillomavirus-related (HPV+) and two metastatic cutaneous squamous cell carcinoma (cSCC) patients were included. EV were isolated using ultracentrifugation from patients’ plasma. DNA was extracted from FFPE tumor tissue and EV. LC-WGS aiming for 0.5-1X coverage was performed using a validated method. CNA profiles were generated using the QDNAseq package, with gains defined as a log2 ratio ≥0.15 and losses < -0.15. Results: CNA profiles of FFPE samples from BOT patients demonstrated significant variation regardless of HPV status, with a mean of 20 regions containing 125 CNA (amplifications or deletions) per sample. The cSCC FFPE samples demonstrated a mean of 23 regions containing 189 CNA per sample. Overall, EV-associated DNA CNA profiles had limited similarity with primary FFPE. EV-associated DNA showed a lower number of CNA regions and CNA, with a mean of 3.7 CNA regions and 11.4 CNA for BOT samples and 6.5 regions and 15.9 CNA for cSCC samples. The HPV-BOT sample showed 2/3 EV-CNA regions matched corresponding FFPE-CNA profile (n = 15). The two HPV+ samples were less consistent with only 1/3 and 1/5 EV-CNA regions matching FFPE-CNA profiles (n = 39 and n = 6, respectively). The two cSCC cases showed more consistency with 4/6 and 6/7 EV-CNA regions matching FFPE-CNA profiles (n = 21 and n = 25, respectively). In the matched CNA regions, the mean CNA in EV-associated DNA was 7.5 and in FFPE-DNA was 97. Conclusions: Although selected EV-associated DNA CNA regions reflected the primary tumors, these were limited in number and did not globally reflect the FFPE derived CNA profiles.

scholarly journals Low-coverage whole-genome sequencing of extracellular vesicle-associated DNA in patients with metastatic cancer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bella Nguyen ◽  
Nicholas C. Wong ◽  
Tim Semple ◽  
Michael Clark ◽  
Stephen Q. Wong ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Squamous Cell ◽  
Metastatic Cancer ◽  
Extracellular Vesicle ◽  
Whole Genome ◽  
Ffpe Samples ◽  
Low Coverage

AbstractLow-coverage whole-genome sequencing (LC-WGS) can provide insight into oncogenic molecular changes. Serum extracellular vesicles (EV) represent a novel liquid biopsy source of tumoral DNA. This study compared copy number alteration (CNA) profiles generated from LC-WGS of formalin-fixed paraffin-embedded (FFPE) tumoral DNA and EV-DNA obtained from cancer patients. Patients with squamous cell carcinoma of the base of tongue (n = 3) and cutaneous squamous cell carcinoma (n = 2) were included. LC-WGS (0.5-1X coverage) was performed on FFPE-DNA and serum EV-DNA. Similarity between CNA profiles was analysed using QDNAseq. FFPE samples had a mean CNA of 31 (range 17–50) over 1.9 × 109 (range 1.0–2.6 × 109) bp in length, and EV samples had a mean CNA value of 17 (range 7–19) over 7.6 × 108 (range 2.9–15 × 108) bp in length. A mean of 8 (range 0–21) CNA over 5.9 × 108 (range 1.6–14 × 108) bp in length was found to overlap between EV and FFPE-derived samples per patient. Although the mean correlation efficient between samples was r = 0.34 (range − .08 to 0.99), this was not statistically significant (p > 0.05). Regions of highest deletion and duplication in FFPE samples were not well reflected in the EV-DNA. Selected CNA regions in EV-associated DNA were reflective of the primary tumor, however appreciation of global CNA and areas of most significant change was lost. The utility of LC-WGS of EV-derived DNA is likely limited to molecular alterations of known interest.

scholarly journals Cell-free tumour DNA analysis detects copy number alterations in gastro-oesophageal cancer patients

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0245488
Author(s):  
Karin Wallander ◽  
Jesper Eisfeldt ◽  
Mats Lindblad ◽  
Daniel Nilsson ◽  
Kenny Billiau ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Oesophageal Cancer ◽  
Copy Number ◽  
Dna Analysis ◽  
Tissue Sample ◽  
Whole Genome ◽  
Copy Number Alterations ◽  
Plasma Dna ◽  
Low Coverage

Background Analysis of cell-free tumour DNA, a liquid biopsy, is a promising biomarker for cancer. We have performed a proof-of principle study to test the applicability in the clinical setting, analysing copy number alterations (CNAs) in plasma and tumour tissue from 44 patients with gastro-oesophageal cancer. Methods DNA was isolated from blood plasma and a tissue sample from each patient. Array-CGH was applied to the tissue DNA. The cell-free plasma DNA was sequenced by low-coverage whole-genome sequencing using a clinical pipeline for non-invasive prenatal testing. WISECONDOR and ichorCNA, two bioinformatic tools, were used to process the output data and were compared to each other. Results Cancer-associated CNAs could be seen in 59% (26/44) of the tissue biopsies. In the plasma samples, a targeted approach analysing 61 regions of special interest in gastro-oesophageal cancer detected cancer-associated CNAs with a z-score >5 in 11 patients. Broadening the analysis to a whole-genome view, 17/44 patients (39%) had cancer-associated CNAs using WISECONDOR and 13 (30%) using ichorCNA. Of the 26 patients with tissue-verified cancer-associated CNAs, 14 (54%) had corresponding CNAs in plasma. Potentially clinically actionable amplifications overlapping the genes VEGFA, EGFR and FGFR2 were detected in the plasma from three patients. Conclusions We conclude that low-coverage whole-genome sequencing without prior knowledge of the tumour alterations could become a useful tool for cell-free tumour DNA analysis of total CNAs in plasma from patients with gastro-oesophageal cancer.

scholarly journals Author Correction: Low-coverage whole-genome sequencing of extracellular vesicle-associated DNA in patients with metastatic cancer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bella Nguyen ◽  
Nicholas C. Wong ◽  
Tim Semple ◽  
Michael Clark ◽  
Stephen Q. Wong ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Metastatic Cancer ◽  
Extracellular Vesicle ◽  
Whole Genome ◽  
Low Coverage

SeqPlus sequencing methodology enables robust whole-genome sequencing, true variant detection, and novel genomic insights from archival esophageal carcinoma FFPE samples.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e13016-e13016
Author(s):  
Shannon Terrell Bailey ◽  
Belynda Hicks ◽  
Bin Zhu ◽  
Nan Hu ◽  
Phil R. Taylor ◽  
...  
Keyword(s):  
Esophageal Carcinoma ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Limit Of Detection ◽  
Whole Genome ◽  
Library Preparation ◽  
High Quality ◽  
Primary Tumors ◽  
Ffpe Samples ◽  
Fresh Frozen

e13016 Background: Whole-genome sequencing (WGS) of formalin-fixed, paraffin-embedded (FFPE) samples could enable novel insights from archival sample collections, yet robust FFPE WGS is challenged by fragmented DNA, uneven genomic coverage & sequencing artifacts attributed to FFPE fixation. We report our proprietary extraction & library preparation methodology (SeqPlus) with high quality, uniform WGS sequencing performance comparable to that from fresh-frozen samples. Methods: We analyzed 20 paired esophageal carcinoma (EC) samples i.e., primary tumors & matched germline samples to assess SeqPlus performance on 10-15-year-old FFPE tissues, measure variant concordance between WGS and a high-depth sequencing panel (269 genes, 400x coverage) & identify novel genomic features. Results: At a targeted 70x WGS tumor sequencing depth, 93% of the genome was covered by ³ 20 reads, 99% of bases had 10x coverage & average duplicate reads were 31%. We noted similar transition/transversion ratios & mutational spectra as from fresh-frozen EC specimens, suggesting that extraction & library preparation contributes to prior FFPE artifacts. Concordance of tumor-specific SNVs & indels derived from WGS & targeted panel was high at 86%. All 76 targeted panel-detected variants above the WGS limit of detection (mutant allele frequency [MAF] > 10%) were detected by WGS, 2 variants (2 tumors) were detected only by WGS, and 12 variants at MAF ≤ 6% (9 tumors) were only detected by the targeted panel. Tumor WGS yielded SNV, indels & CNV findings beyond variants detected by targeted sequencing. WGS enabled detection of 10.4 putative cancer variants per tumor compared to 12 variants per patient from frozen specimens and a median of 7 (up to 16) cancer-associated variants in genes outside the targeted panel. WGS copy number analysis revealed CCND1, EGFR, TP63, and SOX2amplification, CDKN2A/B deletion and additional unrecognized genomic aberrations. Conclusions: Our study reinforces the utility of high-quality, uniform WGS sequencing of archival FFPE cancer samples with SeqPlus and unlocks the potential for massive-scale retrospective genomic analysis of archived pathology samples with associated clinical & outcomes data.

scholarly journals 353 ASAS-EAAP Talk: Low-coverage whole-genome sequencing in local livestock breeds

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 81-82
Author(s):  
Joaquim Casellas ◽  
Melani Martín de Hijas-Villalba ◽  
Marta Vázquez-Gómez ◽  
Samir Id Lahoucine
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Error Rate ◽  
Allele Frequencies ◽  
Paternity Testing ◽  
Sequencing Error ◽  
Whole Genome ◽  
Genomic Evaluation ◽  
Sequencing Error Rate ◽  
Low Coverage

Abstract Current European regulations for autochthonous livestock breeds put a special emphasis on pedigree completeness, which requires laboratory paternity testing by genetic markers in most cases. This entails significant economic expenditure for breed societies and precludes other investments in breeding programs, such as genomic evaluation. Within this context, we developed paternity testing through low-coverage whole-genome data in order to reuse these data for genomic evaluation at no cost. Simulations relied on diploid genomes composed by 30 chromosomes (100 cM each) with 3,000,000 SNP per chromosome. Each population evolved during 1,000 non-overlapping generations with effective size 100, mutation rate 10–4, and recombination by Kosambi’s function. Only those populations with 1,000,000 ± 10% polymorphic SNP per chromosome in generation 1,000 were retained for further analyses, and expanded to the required number of parents and offspring. Individuals were sequenced at 0.01, 0.05, 0.1, 0.5 and 1X depth, with 100, 500, 1,000 or 10,000 base-pair reads and by assuming a random sequencing error rate per SNP between 10–2 and 10–5. Assuming known allele frequencies in the population and sequencing error rate, 0.05X depth sufficed to corroborate the true father (85,0%) and to discard other candidates (96,3%). Those percentages increased up to 99,6% and 99,9% with 0,1X depth, respectively (read length = 10,000 bp; smaller read lengths slightly improved the results because they increase the number of sequenced SNP). Results were highly sensitive to biases in allele frequencies and robust to inaccuracies regarding sequencing error rate. Low-coverage whole-genome sequencing data could be subsequently integrated into genomic BLUP equations by appropriately constructing the genomic relationship matrix. This approach increased the correlation between simulated and predicted breeding values by 1.21% (h2 = 0.25; 100 parents and 900 offspring; 0.1X depth by 10,000 bp reads). Although small, this increase opens the door to genomic evaluation in local livestock breeds.

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