View of the regulatory use of rat liver foci data in the Federal Republic of Germany.
Altered hepatocellular foci (AHF) are suspected of being phenotypic markers of a stage in the sequential process of tumor development in the liver. A number of short-term and mid-term tests, including some that use AHF as an endpoint, have been reviewed by the Federal Health Office to determine if they are suitable to replace long-term animal experiments for predicting the carcinogenic potential of chemicals. Although regulatory authorities recognize the advantages of short-term tests, including a possible reduction in the number of animals used, it is still premature to make a general recommendation regarding the suitability of these tests for regulatory decision-making. At this time, the Commission of European Communities (CEC) follows a decision-tree approach for regulating chemicals coming to the market. Since it is unrealistic to expect a reasonable number of AHF to evaluate in 28-day or 90-day studies, AHF can only be practically evaluated in the conventional long-term bioassay. There is still insufficient knowledge regarding the biological significance of the various phenotypic forms of AHF to use them as a relevant endpoint for regulatory purposes. However, data on AHF derived from routine hematoxylin and eosin (H&E) work can be used to aid in the interpretation of the study and in recommending additional investigations.
Richter-Reichhelm
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HB
Max-von-Pettenkofer Institut, Bundesgesundheitsamt, Berlin, FRG.
D000818:Animals; D015197:Carcinogenicity Tests; D005860:Germany, West; D007883:Legislation, Medical; D008099:Liver / Q000473:pathology* / Q000648:ultrastructure; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced* / Q000473:pathology; D051381:Rats