During the last 10 years, the role of specific nutrients in cancer prevention and cancer treatment has been the subject of intense basic, preclinical, and clinical research. At present, the major focus of nutri- tional oncology is on the mechanisms of carcinogenesis and their modification by nutrients and on cancer prevention studies in animals and humans. Some human epidemiological studies have confirmed the hypothesis, developed on animals, that there is an inverse relation- ship between the intake and/or level of 3-carotene, vitamin A vita- min E, or vitamin C and the risk of cancer,...