ABSTRACT
I. INTRODUCTION Vitamin C (ascorbic acid or ascorbate) is an antioxidant that has received a great deal of attention in recent years relative to prevention and treatment of cancer (1-11), including use of vitamin C supplements (12-16). The human body is under constant attack by reactive oxygen molecules (free radicals and singlet oxygen) that are formed as a natural consequence of normal biochemical activity. Reactive oxygen can damage the body in many ways by altering membrane structure and function. The hypothesis that free radicals may be involved in carcinogenesis is primarily based on observations that many carcinogens are free radicals, are the product of free radical reactions, are converted to free radicals in vivo, or stimulate the production of free radicals. Also, free radicals may be important in tumor initiation or promotion.
