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The Establishment of a Lung Colonization Assay for Circulating Tumor Cell Visualization in Lung Tissues
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Circulating tumor DNA analysis depicts subclonal architecture and genomic evolution of small cell lung cancer

Jingying Nong1, Yuhua Gong2,3, Yanfang Guan2,3

  • 1Department of Medical Oncology, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Research Institute, 101149, Beijing, China.

Nature Communications
|August 8, 2018
PubMed

Insights

Circulating cell-free tumor DNA (ctDNA) sequencing offers a promising approach to study small-cell lung cancer (SCLC) evolution. ctDNA analysis reveals similar subclonal architecture and treatment-induced pathway enrichments, aiding in understanding SCLC genomic changes.

Area of Science:

  • Oncology
  • Genomics
  • Molecular Biology

Background:

  • Small-cell lung cancer (SCLC) subclonal architecture and genomic evolution during treatment remain understudied due to limited longitudinal tumor samples.
  • SCLC's propensity for early hematogenous spread highlights the potential of circulating cell-free tumor DNA (ctDNA) for non-invasive genomic profiling.

Purpose of the Study:

  • To investigate the subclonal architecture and genomic evolution of SCLC using ctDNA.
  • To correlate ctDNA-derived genomic features with patient survival outcomes.
  • To identify genomic alterations enriched in SCLC post-treatment.

Main Methods:

  • Targeted deep sequencing of 430 cancer genes was performed on pre-treatment tumor biopsies and longitudinal plasma samples from 22 SCLC patients.
  • Analysis included comparison of subclonal architecture between tumor DNA and ctDNA.
  • Variant allele frequencies of clonal mutations were assessed for association with progression-free and overall survival.

Main Results:

  • Pre-treatment ctDNA exhibited similar subclonal architecture to paired tumor DNA.
  • Mean variant allele frequency of clonal mutations in pre-treatment ctDNA correlated with patient survival.
  • Post-treatment ctDNA revealed enrichment of mutations in DNA repair and NOTCH signaling pathways.

Conclusions:

  • ctDNA sequencing is a viable tool for characterizing the genomic landscape and subclonal architecture of SCLC.
  • ctDNA analysis can provide insights into the genomic evolution of SCLC under treatment.
  • Genomic alterations in DNA repair and NOTCH pathways are potentially associated with SCLC treatment response or progression.

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