Inter-species comparisons of carcinogenicity

Area of Science:

• Toxicology
• Carcinogenesis Research
• Comparative Oncology

Background:

• Evaluating chemical carcinogenicity is crucial for public health and regulatory decisions.
• Animal models, primarily rats and mice, are standard for assessing carcinogenic potential.
• Understanding species concordance in carcinogenicity is vital for accurate risk assessment.

Purpose of the Study:

• To analyze and compare the carcinogenicity of 250 chemicals across two species (rats and mice).
• To identify the extent of agreement and disagreement in carcinogenic outcomes between species.
• To assess the reliability of single-species animal studies for predicting human cancer risk.

Main Methods:

• Systematic literature review of 250 chemicals from three independent sources.
• Data compilation on carcinogenicity in rats and mice.
• Comparative analysis of chemical effects across species and target organs.

Main Results:

• 38% of chemicals were non-carcinogenic in both species; 44% were carcinogenic in both.
• 43 compounds showed differing results between rats and mice (carcinogenic in one, not the other).
• 64% of chemicals carcinogenic in both species affected the same primary target organ.

Conclusions:

• Significant interspecies variation exists in chemical carcinogenicity.
• Reliance on single-species rodent bioassays may overestimate or underestimate human cancer risk.
• Comparative carcinogenicity data across species is essential for robust human health risk assessments.