[Current knowledge on the action of retinoids in carcinoma of the head and neck]

The retinoids are a pharmacologic class based on the vitamin A or retinol. The most known related derivatives are the all-trans (ATRA), 13 and 9 Cis retinoic acids. The antitumor and differenciative activities have been demonstrated in: in vitro, in vivo and clinical studies. In head and neck cancers, the clinical phase III trials in chemoprevention of second primary tumors have shown discordant results related to the type of retinoic acid. Nuclear retinoic acid receptors are members of the steroid-thyroid and vitamin D3 superfamily of nuclear receptors which regulate differenciation proliferation and apoptosis in cooperation with mediated proteins of the apoptosis (especially p53 protein). A thorough knowledge on the earlier mechanisms involved in carcinogenesis of squamous cell carcinomas would lead to futur reversal therapy with the reversal of pathologic to normal tissues by the restauration of mechanisms of the physiologic control. This futur clinical trial research could provide cancer prevention and control by the induction of cellular differentiation rather than proliferation (retinoids) and/or the expression of tumor-suppressor genes (p53 protein transfection). Finally, the retinoids treatment should be performed in control studies because of the toxicity at high doses.