TGx-DDI (toxicogenomic DNA damage-inducing) biomarker validation: multi-site ring trial supporting regulatory use

Area of Science:

• Toxicology
• Genomics
• Biomarker Development

Background:

• Standard genotoxicity assays often lack specificity, leading to false positives and unnecessary animal testing.
• The TGx-DDI (Toxicogenomic DNA Damage-Inducing) transcriptomic biomarker was developed to improve specificity using gene expression profiling.

Purpose of the Study:

• To validate the TGx-DDI biomarker's reliability and reproducibility across multiple laboratories.
• To assess its performance in distinguishing DNA damage-inducing compounds.

Main Methods:

• A multi-site ring-trial involving four laboratories and 14 blinded compounds.
• Gene expression profiling in TK6 cells using NanoString nCounter.
• Bioinformatics analysis including Nearest Shrunken Centroid, PCA, and Hierarchical Clustering.

Main Results:

• TGx-DDI achieved 100% sensitivity, 86% specificity, and 91% accuracy.
• High interlaboratory concordance (agreement coefficients ≥0.61) and cross-site data correlation (Pearson r > 0.84).
• Reproducible classification of test agents across study sites.

Conclusions:

• TGx-DDI is a robust and reproducible transcriptomic biomarker for genotoxicity testing.
• It enhances specificity by identifying biologically relevant DNA damage responses.
• Integration supports regulatory decisions, reduces animal use, and improves human health risk assessment.