Mechanistic biomarkers in genotoxicity testing: A systematic mapping review of their integration with apical...

Genetic toxicology plays a central role in regulatory safety assessment but remains largely dependent on a standardized battery of established genotoxicity assays. Increasing attention has been directed toward the integration of mechanistic information to improve biological interpretation and human relevance. This study presents a systematic mapping review (2020-2025) of biomarkers and methodological developments in genetic toxicology. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, 1478 records were screened, resulting in 120 primary studies. The analysis showed that established genotoxicity assays, particularly the comet and micronucleus tests, remain dominant (91.7%), reflecting their continued role in regulatory hazard identification. However, 65% of the analyzed studies incorporated mechanistic components, indicating enhanced biological resolution. This mechanistic layer was primarily represented by targeted DNA damage response biomarkers (Level II) and systems-level omics-based or computational approaches (Level III), while 35% focused on technical optimization of established assays (Level I), including automation and high-throughput adaptations. Overall, the results indicate a dual structure in current genetic toxicology research, characterized by the sustained predominance of established regulatory assays alongside a heterogeneous integration of mechanistic and computational methodologies. Rather than replacing apical endpoints, these approaches primarily complement and refine the interpretation of genotoxicity data within weight-of-evidence frameworks. Integration of these biomarkers within Integrated Approaches to Testing and Assessment (IATA) may enhance mechanistic resolution in hazard evaluation, although regulatory maturity varies across platforms and application domains.