The scientific basis for short-term tests for carcinogenicity: non-mammalian systems.

Almost all non-mammalian short-term tests for carcinogenicity measure, in one way or another, the capacity of an agent to cause DNA damage. Short-term tests should be used quantitatively rather than qualitatively, and, despite the difficulties, they should be taken into account when assessing human genetic or carcinogenic risk. It is far more important to understand how the tests work, and what are their limitations, than to standardize them prematurely. When making choices between tests, in addition to predictive value and cost, the discomfort caused to laboratory animals should be taken into account.