1Inhibition of Chemical Carcinogenesis by Phenols, Coumarins, Aromatic Isothiocyanates, Flavones, and Indoles.- I. Introduction.- II. Inhibitors of Chemical Carcinogens.- A. Phenols.- B. Coumarins and Other Simple Lactones.- C. Aromatic Isothiocyanates.- D. Flavones.- E. Indoles.- F. Possible Hazards from Inducers of Increased Microsomal Mixed-Function Oxidase Activity.- III. Discussion.- References.- 2Inhibition of Carcinogen Metabolism and Action by Disulfiram, Pyrazole, and Related Compounds.- I. Introduction.- II. Disulfiram.- A. Commercial and Medicinal Use.- B. Toxicity.- C. Effects on Enzyme Systems.- D. Metabolism.- III. Sodium Diethyldithiocarbamate and Dithiocarbamate Pesticides.- A. Commercial and Medicinal Use.- B. Toxicity.- C. Effects on Enzyme Systems.- IV. Carbon Disulfide.- A. Commercial Use.- B. Effects on Enzyme Systems.- V. Pyrazole.- A. Metabolism, Toxicity, and Enzyme Inhibition.- VI. Polycyclic Aromatic Hydrocarbons: Benzo[a]pyrene and 7,12-Dimethylbenz[a]anthracene.- A. Metabolism.- B. Effects of Thiono Sulfur Compounds on Carcinogenicity.- VII. Hydrazo and Azoxy Carcinogens.- A. 1,2-Dimethylhydrazine.- B. Procarbazine.- VIII. N-Nitrosamines.- A. Dimethylnitrosamine and Diethylnitrosamine.- B. N-Nitrosopyrrolidine.- C. N-n-Butyl-N-(4-hydroxybutyl) nitrosamine.- IX. Arylamines.- A. 2-Acetylaminofluorene.- B. 3,2?-Dimethyl-4-aminobiphenyl.- X. Azo Dyes: 3?-Methyl-4-dimethylaminoazobenzene.- XI. Ultraviolet Light.- XII. Spontaneous Tumors.- XIII. Other Effects of Thiono Sulfur Compounds.- References.- 3Retinoids and Chemoprevention of Cancer.- I. Introduction.- II. Retinoids and Epithelial Cell Differentiation.- III. Suppression of Malignant Transformation and Tumor Promotion by Retinoids.- IV. Retinoid Deficiency and Carcinogenesis.- V. Natural Retinoids and Prevention of Carcinogenesis.- VI. Structure-Activity Relationships of New Synthetic Retinoids.- VII. Prevention of Cancer in Experimental Animals with New Synthetic Retinoids.- VIII. Mechanism of Action of Retinoids in Chemoprevention of Cancer.- IX. Mechanism of Toxicity of Retinoids.- X. Combination Chemoprevention with Retinoids.- References.- 4Ascorbic Acid Inhibition of N-Nitroso Compound Formation in Chemical, Food, and Biological Systems.- I. Introduction.- II. In Vitro Studies.- A. Studies in Acidic Aqueous Solutions.- B. Use of Ascorbate in the Meat Industry.- C. Nitrosation in Lipids and by Nitrogen Oxides.- III. In Vivo Studies.- A. Acute Toxicity Experiments.- B. Carcinogenicity Experiments.- C. Chemical Analysis of Biological Materials.- IV Tests on Carcinogenicity and Mutagenicity of Ascorbic Acid.- V. Effects of Ascorbic Acid on Carcinogenicity and Mutagenicity of N-Nitroso Compounds.- VI. Ascorbic Acid and Carcinogenesis in Man.- VII. Summary and Conclusions.- References.- 5?-Tocopherol (Vitamin E) and Its Relationship to Tumor Induction and Development.- I. Introduction.- A. Mechanisms of Tumor Induction/Inhibition.- II. Vitamin E as an Antitumor Agent.- A. Ultraviolet Light-Induced Carcinogenesis.- B. Polynuclear Aromatic Hydrocarbons.- III. Nitroso Compounds.- A. Carcinogenicity.- B. Mutagenicity.- C. Mechanism of Activation.- D. Implications for Carcinogenesis.- IV. Formation of N-Nitroso Compounds.- A. General Principles.- B. Aqueous Systems.- C. Nonaqueous Systems.- D. Transnitrosation.- V. Blocking N-Nitroso Compound Formation.- A. Principles.- B. Blocking Agents.- C. Integration of Blocking Systems.- VI. ?-Tocopherol Applications.- A. Bacon.- B. Other Foods.- C. Rectal and Colonic Carcinogenesis.- D. Lung Cancer.- E. Bladder Cancer.- F. N-Nitroso Compounds in Blood.- G. Gastric Cancer.- VII. Ascorbic Acid and Tocopherol Effect on Preformed Nitrosamines.- VIII. Summary.- References.- 6Trace Elements and Metals as Anticarcinogens.- I. Introduction.- II. Selenium.- A. Clinical.- B. Animal.- C. Bacterial.- D. Other in Vitro Systems.- III. Zinc.- IV. Copper.- V. Other Trace Elements and Metals.- A. Metal-Metal Anticarcinogenicity.- B. Nutritional Factors.- C. Other Trace Element Effects.- VI. Closing Remarks.- References.- 7Plant Sterols: Protective Role in Chemical Carcinogenesis.- I. Background.- II. Plant Sterols: Structure and Function.- III. Animal Test Systems.- IV. Results.- A. Effect of N-Methyl-N-nitrosourea on Tumor Formation in Animals Given Plant Sterol and / or Bile Acid.- V. Discussion.- References.- 8Immunoprevention.- I. Introduction.- II. Detection of Tumor-Associated Antigens in Experimental Rat Bowel Carcinomas.- III. Evidence that Embryonic Antigens are Associated with Bowel Carcinomas.- IV. Enhanced 1,2-Dimethylhydrazine-Induced Tumorigenesis in Immunosuppressed Rats.- V. Inhibitory Effect on Bowel Carcinogenesis by Immunization with Transplantable Syngeneic Colon Carcinoma.- VI. Inhibitory Effect on Bowel Carcinogenesis by Immunization with Fetal Tissue.- VII. Inhibition of 1,2-Dimethylhydrazine-Induced Carcinogenesis in Multiparous Rats.- VIII. Effect of Tumor Resection on the Development of Additional Primary Tumors.- IX. Regression of Early Primary Bowel Carcinomas by Multimodal Immunological Treatment.- X. Conclusions.- References.- 9Summation and Future Challenges.- I. Introduction.- II. Challenges to Chemists and Molecular and Cell Biologists.- III. Challenges to Epidemiologists and Oncologists.