Fluoropyrimidine Metabolism and Mechanism of Action.- 5-Fluoro-2?-Deoxyuridine: Role of Schedule in its Therapeutic Efficacy.- Comparison of Continuous Infusions and Bolus Injections of 5- Fluorouracil with or without Leucovorin: Implications for Inhibition of Thymidylate Synthase.- Critical Questions for the Future Direction of FU/LV.- Cellular Interactions Between the Natural and Unnatural Isomers of 5-Formyltetrahydrofolate.- Leucovorin as a Prodrug.- Clinical Use of Leucovorin: Intracellular Metabolism.- Some Considerations Concerning the Dose and Schedule of 5FU and Leucovorin: Toxicities of Two Dose Schedules from the Intergroup Colon Adjuvant Trial (INT-0089).- Effects of 5-Fluorouracil on mRNA.- Genetic Variation in Thymidylate Synthase Confers Resistance to 5-Fluorodeoxyuridine.- Experience with 5FU + L-Leucovorin.- 5-Fluorouracil Combined with the Pure [6S]-Stereoisomer of Folinic Acid in High Doses for Treatment of Patients with Advanced Colorectal Carcinoma: A Phase I-II Study of Two Consecutive Regimens.- 5-Fluorouracil Modulation in Colorectal Carcinoma: Experience of German Investigators.- An Overview of Adjuvant Treatment of Colon Cancer.- Dose-Dependent Inhibition of Aspartate Carbamoyltransferase in Peripheral Blood Mononuclear Cells in Patients Receiving N-Phosphonacetyl)-L-Aspartate.- Alternative Approaches to Modulation of Fluoropyrimidines.- Increasing the Efficacy of 5-Fluorouracil with Interferons: Preclinical, Clinical, and Pharmacokinetic Studies.- Enchanced Cytotoxicity of 5-Fluorouracil Combined with [6RS]-Leucovorin and Recombinant Human Interferon-?2a in Colon Carcinoma Cells.- Regulation of Thymidylate Synthase in Human Colon Cancer Cells Treated with 5-Fluorouracil and Interferon-Gamma.- Biochemical Modulation of 5-Fluorouracil by PALA: Mechanism of Action.- Implications of Chronobiology for 5-Fluorouracil (5-FU) Efficacy.- Update on Metabolic Modulation as a Therapeutic Approach for Adult Carcinomas.- Fluorouracil and Leucovorin in Advanced Breast Cancer.- Fluorouracil Modulation in Head and Neck Cancer.- Biomodulation in Head and Neck Carcinomas: Therapeutic Approaches in Europe.- Rationale for the Combination Therapy of 5FU and CDDP.- Biochemical Modulation of Fluoropyrimidines: The "Giscad" Studies.- New Drugs.- Clinical Experience with UFT in Japan.- Clinical Studies of the Modulation of Ftorafur.- The Role of the Reduced-Folate Carrier and Metabolism to Intracellular Polyglutamates for the Activity of ICI D1694.- The History of the Development and Clinical Use of CB 3717 and ICI D1694.- New Sites of Intervention in the Development of New Drugs in Solid Tumors.- P53: A Determinant of the Cell Cycle Response to DNA Damage.- Therapeutic Implications of Molecular Genetics.- Concluding Remarks.- Summary.- Abbreviations.- Author Index.