Needs for biological risk assessment in interspecies extrapolation.

This paper suggests that not all chemicals shown to be carcinogenic in animals may exert this effect in humans exposed to much lower amounts of the chemical. It is possible that agents which differ in their effects in humans and animals may be identified through the application of Biological Risk Assessment to the experimental results. Chemicals tested in systems in which untreated animals develop high background yields of tumors or in which high-dose toxicity may be a critical factor in the induction of carcinogenesis are suggested as candidates requiring very careful consideration before their carcinogenicity in humans is assumed.