Honorary lecture Risk Assessment and Management of Toxic Chemicals: The Needs and Guidelines for Developing Countries.- Molecular Basis of Risk Assessment.- Individual Genetic Constellations as Risk Factors in Chemical Carcinogenesis.- Mechanistic Analysis as a Tool for Carcinogen Risk Assessment.- Molecular Genetic Alterations such as Oncogene Activation as a Tool for the Evaluation of Risks in Chemical Carcinogenesis.- Initiation and Promotion — Useful Concepts for Risk Assessment?.- Human Exposure to Chemical Carcinogens.- Risk Assessment of Naturally Occurring Carcinogens.- Carcinogenic Drugs and their Relevance in Risk Assessment.- A Weight-of-Evidence Approach to Quantitative Cancer Risk Assessment: Information Analysis.- Biologically Based Pharmacokinetics and Cancer Risk Assessment.- Evaluation of Epidemiologic Study Designs for the Assessment of Risk in Chemical Carcinogenesis.- The Role of ‘Negative’ and ‘Nonpositive’ Studies in Occupational Epidemiology.- Weak Associations in Occupational Epidemiology and the Criteria for Deducing Causality.- Aspects of Clinical Oncology in the Assessment in Chemical Carcinogenesis.- Regulations in Risk Assessment.- Provisions on Carcinogenic Substances in the Federal Republic of Germany and the European Community.- Regulations on Chemical Carcinogenesis of the Environmental Protection Agency (EPA).- Regulation of Chemical Carcinogenesis in Japan.- Acknowledgements.- Invited Speakers and Chairmen.