At a recent ECVAM workshop considering ways to reduce the frequency of irrelevant positive results in mammalian cell genotoxicity tests [D. Kirkland, S. Pfuhler, D. Tweats, M.
Aardema, R. Corvi, F. Darroudi, A. Elhajouji, H.-R. Glatt, P. Hastwell, M. Hayashi, P. Kasper, S. Kirchner, A. Lynch, D. Marzin, D. Maurici, J.-R. Meunier, L. Müller, G. Nohynek, J. Parry, E. Parry, V. Thybaud, R. Tice, J. van Benthem, P. Vanparys, P. White, How to reduce false positive results when undertaking
in vitro genotoxicity testing and thus avoid unnecessary followup animal tests: Report of an ECVAM Workshop, Mutat. Res. 628 (2007) 31–55], recommendations for improvements/modifications to existing tests, and suggestions for new assays were made. Following on from this, it was important to identify chemicals that could be used in the evaluation of modified or new assays. An expert panel was therefore convened and recommendations made for chemicals to fit three different sets of characteristics, namely:
- Group 1: Chemicals that should be detected as positive in in vitro mammalian cell genotoxicity tests. Chemicals in this group are all in vivo genotoxins, either due to DNA-reactive or non DNA-reactive mechanisms (e.g., induction of aneuploidy, inhibition of topoisomerase). Most of them are also known carcinogens with a mutagenic mode of action.