PREDICTION OF RODENT CARCINOGENICITY OF FURTHER 30 CHEMICALS BIOASSAYED BY THE US NATIONAL TOXICOLOGY PROGRAM

Recently the U.S. National Toxicology Program (NTP) sponsored a compar ative exercise in which different prediction approaches (both biologic ally and chemically based) were challenged for their predictive abilit ies of rodent carcinogenicity of a common set of chemicals. The exerci se enjoyed remarkable scientific success and stimulated NTP to sponsor a second challenging round of tests, inviting participants to present predictions relative to the rodent carcinogenicity of a further 30 ch emicals; these are currently being tested. In this article, we present our predictions based on structure-activity relationship consideratio ns. In our procedure, first each chemical was assigned to an activity mechanism class and then, with semiquantitative considerations, was as signed a probability carcinogenicity score, taking into account simult aneously the hypothesized action mechanism and physical chemical param eters.