Methodologies, findings, and implications of chemical carcinogenesis studies: their significance for hazard assessment (review)

The experimental techniques, methods of evaluation, and environmental implications of the findings of chemical carcinogenesis studies and related subject areas are herein critically reviewed. It is concluded that firstly, certain presently used procedures provide the best possibilities for the study of the hazardous nature of chemicals. Secondly, other matters, including the dosage of chemicals, animal species, meaning of the term "tumor induction", values of short-term tests, evaluation of tumor incidences, relation of the responses of humans and animals to carcinogenic stimuli, require new attitudes, innovative approaches, and meaningful changes. Thirdly, some of the issues are and will remain controversial until our basic knowledge substantially improves. Finally, it appears advisable to abandon some of the dogmatic attitudes for a more flexible approach.