CAN LABORATORY-ANIMAL CARCINOGENICITY STUDIES PREDICT CANCER IN EXPOSED CHILDREN

A key to the prevention of childhood cancer is the control of carcinog ens to which children are exposed. The first step in this process is t o identify those chemicals that are likely to cause cancer in children . The best way to identify carcinogens, today, is the use of the roden t lifetime cancer test-the bioassay. The test has vocal critics, but i s adequately reliable a properly used. Perhaps the major criticism con cerns the use of the maximum tolerated dose as the highest dose tested . Critics claim that this dose causes cellular killing. The resultant cellular proliferation ''fixes'' preexisting mutations that can lead t o cancer. This occurs but in a small fraction of the tests, and the hi gh dose is necessary to achieve statistical sensitivity. All human car cinogens have been shown, when properly studied. to be carcinogenic in rodents. Many human carcinogens were first shown to cause cancer in r odent tests. Regulators rarely ban chemicals that have been demonstrat ed to be carcinogenic. Further, most chemicals in use today have not b een properly tested. The potential errors in the rodent cancer test se em small when compared to the errors in the economic projections of th e effects of restricting chemicals. Although not perfect, the rodent c ancer test, when used properly, can help protect our children, and us, from cancer.