The role of vitamin A in cancer.

The differentiation and maintenance of epithelial tissues is a well-known function of vitamin A. The most dramatic expression of this is the antineoplastic effect. This biological activity of vitamin A is reviewed with regard to anticarcinogenesis, the reversal of transformation and a possible role in cancer therapy. A brief account is given of vitamin A absorption and transport in the body and the importance of varying levels of cellular binding proteins in normal and malignant tissues.