Toxicities derived from anti-tumor screening data.

A recent study published by the National Academy of Sciences emphasized an acute shortage of data on the toxic effects of chemicals in man and animals. This shortage makes risk assessment difficult and impacts seriously on the development of a sound environmental policy. The National Cancer Institute, in its search for effective anti-cancer agents, has determined quantitative as well as qualitative toxicities for a large number of chemicals. Probit analysis was used to derive lethalities (LD50s) from data obtained in the process of testing anti-cancer agents in mice. These data were compared with those derived from testing those same agents in normal mice and it was found that a correlation exists between the two toxicities. Toxicities derived from NCI testing in normal animals were compared with published values and a similar correlation was found. LD50s were derived for all compounds tested in normal mice as well as those tested in mice bearing L1210 and P388 lymphocytic leukemias. Over 32,000 LD50s were derived for 22,597 unique compounds.