Short-term test results for NTP noncarcinogens: an alternate, more predictive battery

A battery of short-term tests used to predict whether or not a chemical is a carcinogen must be both sensitive (correctly identifying carcinogens) and specific (correctly identifying noncarcinogens). A recent publication [Shelby and Stasiewicz, 1984, Environ Mutagen 6:871-876] of results in four short-term tests for 70 noncarcinogens tested under the aegis of the National Toxicology Program (NTP) indicates that the battery of short-term tests lacked specificity. We have analyzed these results using the Carcinogen Prediction and Battery Selection (CPBS) procedure and calculated that the specificity of the NTP battery is indeed very low, i.e., 0.50. Using published data from NTP, the Gene Tox program of EPA, and the collaborative study of the WHO International Programme on Chemical Safety, we have constructed an alternate battery that has fewer false positives; this battery has a specificity of 0.80. Thus, the lack of specificity of the original NTP battery does not imply that no set of short-term tests is able to predict carcinogenicity accurately.