Alleged 'misconceptions' distort perceptions of environmental cancer risks

In a series of papers, Ames and col leagues allege that the scientific and public health communities have perpetuated a series of 'misconceptions' tha t resulted in inaccurate identification of chemicals that pose potential hu man cancer risks, and misguided cancer prevention strategies and regulatory policies. They conclude that exposures to industrial and synthetic chemica ls represent negligible cancer risks and that animal studies have little or no scientific value for assessing human risks, Their conclusions are based on flawed and untested assumptions. For instance, they claim that syntheti c residues on food can be ignored because 99.99% of pesticides humans eat a re natural, chemicals in plants are pesticides, and their potential to caus e cancer equals that of synthetic pesticides. Similarly, Ames does not offe r any convincing scientific evidence to justify discrediting bioassays for identifying human carcinogens. Ironically, their arguments center on a rank ing procedure that relies on the same experimental data and extrapolation m ethods they criticize as being unreliable for evaluating cancer risks. We a ddress their inconsistencies and flaws, and present scientific facts and ou r perspectives surrounding Ames' nine alleged misconceptions. Our conclusio ns agree with the International Agency for Research on Cancer, the National Toxicology Program, and other respected scientific organizations: in the a bsence of human data, animal studies are the most definitive for assessing human cancer risks, Animal data should not be ignored, and precautions shou ld be taken to lessen human exposures, Dismissing animal carcinogenicity fi ndings would lead to human cancer cases as the only means of demonstrating carcinogenicity of environmental agents. This is unacceptable public health policy.