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Updated: May 19, 2026
13:24
Integration of Wet and Dry Bench Processes Optimizes Targeted Next-generation Sequencing of Low-quality and Low-quantity Tumor Biopsies
Published on: April 11, 2016
A complete human pancreatic cancer genome
Justin Wagner1, Ayse G Keskus2, Keisuke K Oshima3
1National Institute of Standards and Technology, Material Measurement Laboratory, 100 Bureau Dr., Gaithersburg, MD 20899, USA.
Biorxiv : the Preprint Server for Biology
|May 18, 2026
Summary
This study resolves complex cancer genome structures by creating complete, haplotype-resolved assemblies. This reveals thousands of hidden somatic variants in repetitive DNA, crucial for understanding cancer evolution and improving precision medicine.
Area of Science:
- Genomics
- Cancer Biology
- Bioinformatics
Background:
- Cancer genome sequencing is vital for precision medicine but challenged by reference gaps and repetitive DNA.
- Somatic structural variations, especially in centromeric satellite DNA, are difficult to detect.
- These limitations obscure the full spectrum of somatic variants and their impact on tumor evolution.
Purpose of the Study:
- To construct and curate near-complete, haplotype-resolved genome assemblies of a pancreatic cancer cell line and matched normal tissue.
- To identify the full spectrum of somatic variants, including complex rearrangements in previously intractable regions.
- To establish a benchmark for developing algorithms to analyze challenging cancer genome segments.
Main Methods:
- Haplotype-resolved genome assembly of paired normal-tumor samples.
- Karyotyping to confirm chromosomal abnormalities in the tumor.
- Direct comparison of tumor and normal haplotypes to identify somatic variants.
- Analysis of variants in repetitive regions like centromeres, acromeres, and telomeres.
Main Results:
- Near-complete tumor assembly recapitulated all 35 tumor chromosomes, including hybrid chromosomes with functional dicentric and fused centromeres.
- Identified over 7,000 somatic variants altering >1 Mbp of sequence in repetitive regions, previously hidden by reference gaps.
- Revealed that 44% of somatic small variants alter germline variants, impacting mutational signatures, and highlighted the role of hypomethylated germline LINE insertions in mutation burden.
Conclusions:
- Centromeric, acrocentric, and telomeric regions harbor extensive somatic and epigenetic changes previously missed.
- Complete tumor genome resolution enhances understanding of cancer's structural plasticity and breakage-fusion-bridge cycles.
- These curated assemblies provide a critical foundation for future algorithms to analyze intractable cancer genome regions.
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