USE OF BIOLOGICAL MARKERS IN RISK ASSESSMENT

Measurements of intermediate end points in the carcinogenic process ma y reduce uncertainty in human risk assessment from bioassay data, by i dentifying sources of interspecies variation and dose nonlinearity. Th is paper describes desirable properties of such markers: persistence, predictive power, temporal relevance, and consistency across dose rate and species. We illustrate these properties by evaluating markers for squamous cell nasal carcinoma in rodents exposed to formaldehyde. We also discuss design issues for bioassays that evaluate markers and tum ors simultaneously at necropsy.