SPECULATIONS ON THE RODENT CARCINOGENICITY OF 30 CHEMICALS CURRENTLY UNDER EVALUATION IN RAT AND MOUSE BIOASSAYS ORGANIZED BY THE US NATIONAL TOXICOLOGY PROGRAM

As a contribution to the second round of rodent carcinogenesis predict ion organised by the U.S. National Institute of Environmental Health S ciences (NIEHS), speculative predictions for 30 chemicals currently un der evaluation in U.S. National Toxicology Program (NTP) rodent bioass ays are presented. Core chemical data received from NIEHS were supplem ented by relevant information from commercially available scientific d atabases to provide input for reasoned assessment. For each chemical, carcinogenesis by a genotoxic or nongenotoxic mechanism or noncarcinog enesis is predicted; species-and target organ-specific predictions are also presented, together with arbitrary indices of confidence in each such prediction. In all or nearly all cases, on element of informed s peculation was a necessary part of the prediction process, but the rat ionale for each decision is briefly described. it is predicted that te n chemicals will prove noncarcinogenic, five will be carcinogenic to m ice only, and 15 will induce tumours in both species. (C) 1996 Wiley-L iss, Inc.