LEARNING RULES TO PREDICT RODENT CARCINOGENICITY OF NONGENOTOXIC CHEMICALS

The results of short-term assays (induction of chromosomal aberrations and sister-chromatid exchanges, oncogenic transformations and cellula r toxicity) together with MTD (maximum tolerated dose) values and phys ical chemical properties of non-genotoxic (i.e. Salmonella non-mutagen s) carcinogens and non-carcinogens were submitted to RL, an inductive learning program. RL was able to learn rules that correctly predicted between 70 and 80% of non-genotoxic chemicals. This is a marked improv ement over current predictions using only the results of short-term as says and exceeds the predictions of human experts that used the whole spectrum of acute and subchronic toxicity results as well as human kno wledge and intuition.