Identification Methods of Tumor Tissue Origin Based on Different STR Typing Kits

Area of Science:

• Forensic Genetics
• Molecular Biology
• Oncology

Background:

• Accurate identification of tumor tissue origin is crucial for diagnosis and treatment.
• Short tandem repeat (STR) typing is a powerful tool in genetic analysis.
• Existing STR typing kits may have limitations in tumor tissue origin identification.

Purpose of the Study:

• To establish and evaluate methods for identifying tumor tissue origin using commonly used STR typing kits.
• To compare the performance of different STR loci in tumor origin identification.
• To develop an optimized STR-based model for tumor tissue origin tracing.

Main Methods:

• Utilized the ForenSeq DNA Signature Prep kit to analyze 27 autosomal STR loci in tumor and normal tissue samples.
• Simulated genotyping data for full sibling and parent-child pairs.
• Calculated allele sharing (A) and identity by state (IBS) scores across different groups.
• Developed and validated identification models using 8 commercial STR kits and a 15-STR loci model.

Main Results:

• Significant differences in allele sharing (A) and IBS scores were observed between tumor tissues and unrelated or simulated familial groups.
• Identified specific STR loci (e.g., CSF1PO, FGA, vWA) with higher A2 levels in tumor tissues.
• Established tumor tissue origin identification models with high accuracy (97.59%-99.89%), sensitivity (100%), and specificity (97.56%-99.88%).
• The 15-STR loci model outperformed commercial kits with 100% sensitivity, 99.88% specificity, and 99.89% accuracy.

Conclusions:

• Successfully established tumor tissue origin identification methods using 8 commercial STR kits.
• The 15-STR loci model offers superior performance for tumor origin tracing.
• Selected 15 STR loci provide a strong data basis for future tumor origin tracing kit development.