Can Simple Test in Bacteria Identify Cancer-Causing Chemicals in Humans?

Seminar by Angela Creager, Professor in the History of Science at Princeton University and 2024-2025 research-fellow at the Paris IAS, with members of the SPHERE laboratory (CNRS, Université Paris-Cité, Paris 1 Panthéon-Sorbonne). The session will be devoted to a collective discussion of her manuscript on the history of the regulation of standardised tests in cancerology.

Presentation

From the 1960s to the 1980s, US officials sought to reduce cancer incidence by
regulating chemical exposures. However, rodent carcinogenicity tests were lengthy and expensive, making identifying the carcinogens among all 60,000 chemicals on the market impractical.

Introduced in 1973, the quick and inexpensive “Ames test” indicated whether a
chemical caused mutations in bacteria, and putatively cancer in humans. In the 1970s and 1980s, scientific societies, international bodies, and government agencies launched efforts to validate the Ames test for carcinogenicity. While the Ames test became the most commonly used mutagenicity (or genotoxicity) test, technical determinations of its validity could not resolve policy issues concerning how much predictiveness was required for regulatory action. Furthermore, the availability of new animal carcinogenicity data through the 1980s affected the validation of the Ames test. Examining the challenges with validating even a very successful chemical safety test reveals the limits of what can be expected from regulatory science.