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Follow-up actions from positive results of in vitro genetic toxicity testing
Citation:
Dearfield, K. L., V. Thybaud, M. CIMINO, L. Custer, A. Czich, S. Hester, J. H. Kim, D. Kirkland, D. D. Levy, E. Lorge, M. M. Moore, G. Ouedraogo-Arras, M. Schuler, W. Suter, K. Sweder, K. Tarlo, J. van Benthem, F. van Goethem, AND K. L. Witt. Follow-up actions from positive results of in vitro genetic toxicity testing. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS. John Wiley & Sons, Inc, Hoboken, NJ, 52(3):177-204, (2011).
Impact/Purpose:
This is a ILSI-HESI workgroup project provided to evaluate positive in vitro genotox assays.
Description:
Appropriate follow-up actions and decisions are needed when evaluating and interpreting clear positive results obtained in the in vitro assays used in the initial genotoxicity screening battery (i.e., the battery of tests generally required by regulatory authorities) to assist in overall risk-based decision making concerning the potential effects of human exposure to the agent under test. Over the past few years, the Iternational Life Sciences Institute's (ILSI's) Health and Environmental Sciences Institute (HESI) Project Committee on the Relevance and Follow-up of Positive Results in In Vitro Genetic Toxicity (IVGT) developed a decision process flow chart to be applied in case of clear positive results in vitro. The flow chart provides for a variety of different possibilities and allows flexibility in choosing follow-up action(s), depending on the results obtained in the initial battery of assays and available information. The Review Subgroup of the IVGT committee highlighted the importance ofproperly analyzing the existing data, and considering potential confounding factors (e.g., possible interactions with the test systems, presence of impurities, irrelevant metabolism), and chemical modes of action when analyzing and interpreting positive results in the in vitro genotoxicity assays and determining appropriate follow-up testing. The Review Subgroup also examined the characteristics, strengths, and limitations of each of the existing in vitro and in vivo genotoxicity assays to determine their usefulness in any follow-up testing.
