Defining the heterogeneity landscape of pancreatic cancer copy number alterations.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e15776-e15776
Author(s):  
Timour Baslan ◽  
Jie Wu ◽  
Yee Him Cheung ◽  
Jonathan Bermeo ◽  
Nevenka Dimitrova
Keyword(s):  
Pancreatic Cancer ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Copy Number ◽  
Somatic Mosaicism ◽  
Copy Number Variations ◽  
Whole Genome ◽  
Copy Number Alterations ◽  
Clonal Heterogeneity ◽  
Limited Effectiveness

e15776 Background: Pancreatic cancer (PDAC) is projected to become the second leading cause of cancer related mortality by 2030. Bulk whole genome sequencing studies of PDAC have characterized the landscape of clonal mutations and highlighted the prominence of copy number alterations (CNAs) in PDAC genomes. However, little is known with regards to the extent of sub-clonal heterogeneity of somatic CNAs and it is hypothesized that this heterogeneity is a contributing factor to the limited effectiveness of existing therapies. Methods: We retrieved absolute copy number information using bulk sparse whole genome sequencing of multi-region sampled PDAC samples as well as matching primary-metastasis tumor samples from over 100 patients. In addition, we analyzed copy number variations in a subset of these samples (n = 15) at single-cell resolution (~1000 cells in total). Results: We describe a detailed picture of sub-clonal CNAs genetic heterogeneity. Our results illustrate, among other findings, (1) extensive sub-clonal diversity of CNAs giving rise to many genetically unique sub-clonal cancer populations, (2) somatic mosaicism of chromosomal amplicons in single-cancer cells, (3) variation in the dosage of cancer genes, including the KRAS oncogene, in different tumor sub-clones and (4) somatic alterations, such as amplification of 8q11 containing the metastasis promoting gene IKBKB, associated with primary PDAC progression to liver metastasis. Conclusions: Our results offer an in-depth view of the sub-clonal heterogeneity of somatic CNAs in pancreatic cancer and illustrate ways in which such heterogeneity could lead to therapeutic resistance.

Highly Recurrent Copy Number Alterations and Insight Into The Origins Of 6q Deletions In Waldenström’s Macroglobulinemia Revealed By Whole Genome Sequencing

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4254-4254
Author(s):  
Zachary Hunter ◽  
Lian Xu ◽  
Guang Yang ◽  
Xia Liu ◽  
Yang Cao ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Copy Number ◽  
Statistical Significance ◽  
Chromosome 6 ◽  
Whole Genome ◽  
Copy Number Alterations ◽  
Waldenström’S Macroglobulinemia ◽  
Waldenstrom's Macroglobulinemia ◽  
Waldenström's Macroglobulinemia

Abstract Background Over 90% of patients with Waldenström's Macroglobulinemia (WM), and 50-80% of patients with the precursor condition, IgM MGUS, express MYD88 L265P. These findings suggest that other mutations may support progression of IgM MGUS to WM. Chromosomal aberrations including large losses in 6q are commonly present in WM patients, though the gene loss accounting for WM pathogenesis remains unclear. We therefore sought to delineate copy number alterations (CNA) and structural variants using whole genome sequencing (WGS) in order to more clearly define other important gene alterations in WM. Methods DNA from CD19+ bone marrow lymphoplasmacytic lymphoma cells (LPC) and CD19-depleted peripheral blood mononuclear cells from 10 WM patients was used for paired tumor/germline analysis by WGS. Coverage in the tumor sample was divided by the coverage in the paired germline sample for each matching position, resulting in coverage ratios for each 100Kb window. Statistically significant windows within each genome were then analyzed across the cohort by randomizing the coverage positions to assess the probability of observing the given frequency of a CNA by random chance. TaqMan quantitative polymerase chain reaction (PCR) copy number assays was used to validate findings. Translocations were validated by Sanger sequencing across the breakpoint including flanking sequences. Results Functional annotation for identified CNAs was undertaken using Ingenuity Pathway Analysis that revealed a significant enrichment for pathways dysregulated in B-cell malignancies (Table 1). Iteratively randomizing the genomic position of CNAs not related to the chromosome 6 deletions revealed a greater than 3 fold increase in the targeting of COSMIC genes than expected by chance (p< 0.001). Affected genes in the COSMIC census were BTG1 (9/10; 90%), FOXP1 (7/10; 70%), FNBP1 (7/10; 70%), CD74 (7/10; 70%), TOP1 (6/10; 60%), MYB (5/10; 50%), CBLB (5/10; 50%), ETV6 (5/10; 50%), TNFAIP3 (5/10; 50%), FBXW7 (5/10; 50%), PRDM1 (5/10; 50%), TFE3 (4/10; 40%), JAK1 (4/10; 40%), MAML2 (4/10; 40%), FAM46C (4/10; 40%), EBF1 (4/10; 40%), STL (4/10; 40%), and BIRC3 (4/10; 40%). Other affected genes of interested included PRDM2 (8/10; 80%), HIVEP2 (8/10; 80%), ARID1B (7/10; 70%) as well as LYN (7/10; 70%). There were no singular regions of statistical significance in 6q to denote a minimally deleted region though neither of the previously suspected target genes for 6q loss, PRDM1 and TNFAIP3, were included in the regions of highest statistical significance. Losses in HIVEP2 (8/10; 80%) as well as ARID1B (7/10; 70%) and BCLAF1 (7/10; 70%) constituted the most common deletions in chromosome 6, and were present in patients with and without the large-scale losses in 6q. While no recurrent translocations were noted in this study, 2 or the 5 (40%) of the 6q deletions corresponded with translocation events. In one case, this was a result of chromothripsis focused on 6q while in the other case, a t(6;X) translocation linked to the amplification of Xq was identified. Validation studies confirmed presence of somatic deletions in BTG1 (4/5; 80%) at Chr. 12q21.33, HIVEP2 (4/5; 80%) at 6q24.2, LYN (3/5 60%) at 8q12.1, PLEKHG1 (3/5; 60%) at 6q25.1, ARID1B (3/5 60%) at 6q25.1, PDRM2 (2/5; 40%) at 1p36.21, FOXP1 (2/5; 40%) at 3p13, and MKLN1 (2/5 40%) at 7q32. As some CVAs were subclonal, we validated the correlation between the PCR relative copy number and WGS coverage predictions (rho = .926; p =2.2x10-16). Conclusions Highly recurrent CNAs are present in WM LPCs that include genes with critical regulatory roles in lymphocytic growth and survival signaling. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Identification of Medium-Sized Copy Number Alterations in Whole-Genome Sequencing

2014 ◽  
Vol 13s3 ◽  
pp. CIN.S14023
Author(s):  
Hatice Gulcin Ozer ◽  
Aisulu Usubalieva ◽  
Adrienne Dorrance ◽  
Ayse Selen Yilmaz ◽  
Michael Caligiuri ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Copy Number ◽  
Whole Genome Sequencing Data ◽  
Whole Genome ◽  
Copy Number Alterations ◽  
Sequencing Data ◽  
Entire Genome ◽  
Multiple Challenges ◽  
Cost Efficient

The genome-wide discoveries such as detection of copy number alterations (CNA) from high-throughput whole-genome sequencing data enabled new developments in personalized medicine. The CNAs have been reported to be associated with various diseases and cancers including acute myeloid leukemia. However, there are multiple challenges to the use of current CNA detection tools that lead to high false-positive rates and thus impede widespread use of such tools in cancer research. In this paper, we discuss these issues and propose possible solutions. First, since the entire genome cannot be mapped due to some regions lacking sequence uniqueness, current methods cannot be appropriately adjusted to handle these regions in the analyses. Thus, detection of medium-sized CNAs is also being directly affected by these mappability problems. The requirement for matching control samples is also an important limitation because acquiring matching controls might not be possible or might not be cost efficient. Here we present an approach that addresses these issues and detects medium-sized CNAs in cancer genomes by (1) masking unmappable regions during the initial CNA detection phase, (2) using pool of a few normal samples as control, and (3) employing median filtering to adjust CNA ratios to its surrounding coverage and eliminate false positives.

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 Clinical-grade validation of whole genome sequencing reveals robust detection of low-frequency variants and copy number alterations in CLL

2018 ◽  
Vol 182 (3) ◽  
pp. 412-417 ◽  
Author(s):  
Jenny Klintman ◽  
Katerina Barmpouti ◽  
Samantha J. L. Knight ◽  
Pauline Robbe ◽  
Hélène Dreau ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Copy Number ◽  
Low Frequency ◽  
Whole Genome ◽  
Clinical Grade ◽  
Copy Number Alterations ◽  
Robust Detection

scholarly journals ascatNgs: Identifying Somatically Acquired Copy-Number Alterations from Whole-Genome Sequencing Data

2016 ◽  
Vol 56 (1) ◽  
pp. 15.9.1-15.9.17 ◽  
Author(s):  
Keiran M. Raine ◽  
Peter Van Loo ◽  
David C. Wedge ◽  
David Jones ◽  
Andrew Menzies ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Copy Number ◽  
Whole Genome Sequencing Data ◽  
Whole Genome ◽  
Copy Number Alterations ◽  
Sequencing Data

scholarly journals Submegabase copy number variations arise during cerebral cortical neurogenesis as revealed by single-cell whole-genome sequencing

2018 ◽  
Vol 115 (42) ◽  
pp. 10804-10809 ◽  
Author(s):  
Suzanne Rohrback ◽  
Craig April ◽  
Fiona Kaper ◽  
Richard R. Rivera ◽  
Christine S. Liu ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Single Cell ◽  
Genome Sequencing ◽  
Copy Number ◽  
Cortical Development ◽  
Building Blocks ◽  
Copy Number Variations ◽  
Whole Genome ◽  
Mature Brain ◽  
The Brain

Somatic copy number variations (CNVs) exist in the brain, but their genesis, prevalence, forms, and biological impact remain unclear, even within experimentally tractable animal models. We combined a transposase-based amplification (TbA) methodology for single-cell whole-genome sequencing with a bioinformatic approach for filtering unreliable CNVs (FUnC), developed from machine learning trained on lymphocyte V(D)J recombination. TbA–FUnC offered superior genomic coverage and removed >90% of false-positive CNV calls, allowing extensive examination of submegabase CNVs from over 500 cells throughout the neurogenic period of cerebral cortical development in Mus musculus. Thousands of previously undocumented CNVs were identified. Half were less than 1 Mb in size, with deletions 4× more common than amplification events, and were randomly distributed throughout the genome. However, CNV prevalence during embryonic cortical development was nonrandom, peaking at midneurogenesis with levels triple those found at younger ages before falling to intermediate quantities. These data identify pervasive small and large CNVs as early contributors to neural genomic mosaicism, producing genomically diverse cellular building blocks that form the highly organized, mature brain.

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