The use of mechanistic data in the risk assessments of ten chemicals: an introduction to the chemical-specific reviews.

The International Expert Panel on Carcinogen Risk Assessment of the American Health Foundation has planned, directed and reviewed in-depth analyses of mechanistic data for 10 rodent carcinogens. The purpose of this review was to illustrate the use of mechanistic data in carcinogen risk assessment. The mechanisms by which a chemical produces cancer in rodents provided important information for determining whether or not humans would be at risk at low exposure levels. For epigenetic (non-DNA-reactive) carcinogens, current exposure levels for these chemicals below a threshold do not pose a risk. For DNA-reactive agents at sufficient exposures, humans would be expected to be at risk. However, protective mechanisms may lower the expected risk, especially at low-level exposures.