The SOS chromotest: a review

Area of Science:

• Toxicology
• Genotoxicity Testing
• Biochemical Assays

Background:

• The SOS chromotest is a widely used short-term assay for detecting genotoxic compounds.
• Comparison with the Ames test, a standard mutagenicity assay, is crucial for understanding genotoxicity detection capabilities.
• Evaluating genotoxicity is vital for assessing potential carcinogenicity and public health risks.

Purpose of the Study:

• To comprehensively review and analyze the performance of the SOS chromotest across numerous publications.
• To compare the SOS chromotest results with those of the Ames test for a large set of chemicals.
• To assess the correlation between SOS induction, mutagenesis, and carcinogenicity classifications.

Main Methods:

• Systematic review of over 100 publications involving 751 chemicals tested with the SOS chromotest.
• Comparative analysis of SOS chromotest results against Ames test data for 452 compounds.
• Correlation analysis between genotoxicity assay results and carcinogenicity classifications (e.g., Lewis classification).

Main Results:

• The SOS chromotest identified genotoxic activity in 54% (404/751) of tested chemicals, with potencies spanning over 8 orders of magnitude.
• 82% (373/452) concordance was observed between the SOS chromotest and the Ames test; discrepancies were often due to interpretation of weak results.
• The SOS chromotest showed lower sensitivity but higher specificity for identifying carcinogens compared to the Ames test, with results complementing each other.

Conclusions:

• The SOS chromotest is a rapid, simple, and adaptable assay for genotoxin screening, suitable as an early test in a battery.
• While the Ames test demonstrates higher sensitivity for carcinogen detection, the SOS chromotest's specificity is advantageous in discriminating non-carcinogens.
• The SOS chromotest and Ames test results are highly correlated and can be used complementarily for robust genotoxicity assessment.