Technical and biological constraints on ctDNA-based genotyping.

Area of Science:

• Oncology
• Genomics
• Molecular Diagnostics

Background:

• Circulating tumor DNA (ctDNA) provides non-invasive genomic profiling for cancer management.
• ctDNA analysis is increasingly used clinically, from diagnosis to advanced disease stages.
• In metastatic cancer, ctDNA detects actionable genomic alterations like mutations, CNVs, and rearrangements.

Purpose of the Study:

• To investigate the interplay between ctDNA fraction (ctDNA%), methodology, and the sensitivity-specificity of detecting genomic alterations in prostate cancer.
• To address the challenges posed by unpredictable ctDNA fractions in liquid biopsy interpretation.
• To offer guidance for overcoming technical complexities in identifying clinically relevant genomic alterations in ctDNA.

Main Methods:

• Analysis of ctDNA characteristics in prostate cancer patients.
• Evaluation of different assay designs and their impact on variant detection.
• Correlation of ctDNA fraction with the sensitivity and specificity of identifying somatic mutations, CNVs, and structural rearrangements.

Main Results:

• The ctDNA fraction significantly impacts the detectability of various genomic alterations.
• Assay design critically influences the types of genomic alterations identifiable via ctDNA.
• Specific relationships were elucidated between ctDNA%, methodology, and detection accuracy for prostate cancer.

Conclusions:

• Accurate interpretation of ctDNA requires careful consideration of ctDNA fraction and assay methodology.
• Recommendations are provided to optimize the detection of clinically relevant genomic alterations in prostate cancer ctDNA.
• Standardizing ctDNA analysis protocols can enhance the reliability of liquid biopsy in clinical oncology.