Detection of PIK3CA hotspot mutations in canine mammary tumors using droplet digital PCR: tissue validation and liquid biopsy feasibility

• Published in: Scientific reports 2024-10, Vol.14 (1), p.25587-10, Article 25587
• Main Authors: Seung, Byung-Joon, Sur, Jung-Hyang
• Format: Article
• Language: English
• Subjects: 631/67/1347; 631/67/1857; 692/4028/67; Animals; Biomarkers, Tumor - genetics; Biopsy; Canine mammary tumors; Canis lupus familiaris; Circulating tumor DNA; Class I Phosphatidylinositol 3-Kinases - genetics; Dog Diseases - diagnosis; Dog Diseases - genetics; Dog Diseases - pathology; Dogs; Domestic animals; Droplet digital PCR; Feasibility Studies; Female; High-Throughput Nucleotide Sequencing - methods; Humanities and Social Sciences; Invasiveness; Liquid biopsy; Liquid Biopsy - methods; Malignancy; Mammary Neoplasms, Animal - diagnosis; Mammary Neoplasms, Animal - genetics; Mammary Neoplasms, Animal - pathology; Medical research; Monitoring methods; multidisciplinary; Mutation; Mutation hot spots; Next-generation sequencing; PIK3CA mutations; Polymerase chain reaction; Polymerase Chain Reaction - methods; Science; Science (multidisciplinary); Sensitivity analysis; Sensitivity and Specificity; Tumors
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-024-76820-0

Domestic dogs ( Canis lupus familiaris ) serve as valuable translational models for human cancer research due to their biological similarities. Canine mammary tumors (CMTs), frequently diagnosed in female dogs, share various characteristics with human breast cancers. This study investigates the PIK3CA (H1047R) mutation in CMTs using droplet digital PCR (ddPCR) and explores the potential of liquid biopsy for non-invasive detection. We analyzed 80 formalin-fixed, paraffin-embedded (FFPE) CMT tissue samples and compared ddPCR results with next-generation sequencing (NGS) data, achieving high concordance. Plasma and serum samples were also assessed for mutation concordance with tissue results. Our findings indicate a higher frequency of the  PIK3CA (H1047R) mutations in benign and grade I malignant CMTs compared to more aggressive malignancies. The ddPCR assay demonstrated high sensitivity and specificity, with plasma testing showing 78.6% sensitivity and 87.5% specificity, and serum testing showing 66.7% sensitivity and 90.0% specificity. These results highlight the viability of liquid biopsy as a minimally invasive method for monitoring PIK3CA mutations in canine patients. The study suggests that liquid biopsy techniques hold significant promise for improving the early detection and monitoring of canine cancers, warranting further research to refine these methods and explore their applications in canine cancer diagnostics and treatment.