Retinoids in head and neck chemoprevention.

Over the last few years, we have witnessed tremendous progress in both basic and clinical research on retinoids. Preclinical studies have indicated the potential of retinoids in cancer prevention and therapy, but the actual successful application of retinoids in clinical chemoprevention trials has been the recent and exciting development in the field of retinoid research. Our understanding of the role of retinoids in normal developmental processes and the differentiation of normal and malignant cells, and the fundamental discovery of the nuclear retinoid receptors that act as transcription modulating factors regulating specific gene expression have been major advances in the field of basic retinoid research. Chemoprevention is the newest research approach in our efforts to control upper-aerodigestive tract cancers, which have one of the lowest cure rates among epithelial malignancies, and in which the occurrence of second primary tumors further burdens the dismal prognosis of patients. The efficacy of retinoids in the reversal of oral premalignant lesions and the prevention of second primary tumors has generated tremendous enthusiasm among retinoid researchers, particularly those in the field of chemoprevention. Current explorations of combinations of retinoids with biologic response modifiers such as alpha-interferon, as well as new receptor-selective retinoids, hold promise for the future.