N De Vries et al.
Journal of cellular biochemistry. Supplement, 17F, 270-277 (1993-01-01)
The most commonly used chemopreventive agents in the prevention of oral leukoplakia, head and neck cancer, and lung cancer are beta-carotene, vitamin A, and other retinoids. One of the few chemopreventive agents not in this group and presently being used