Retinoic acid-binding protein in human squamous cell carcinomas of the ORL region.

In some squamous cell carcinomas of the otorhinolaryngologic region with different grades of differentiation, a protein was found that specifically binds vitamin A acid. In 28 of 37 tumors, the retinoic acid-binding sites were found in significant amounts, according to the authors' data. Areas with metastases showed a lower incidence of retinoic acid-binding, whereas in all normal epiglottis and vocal cord tissue specimens the binding was present. The possible significance of the protein-binding for the biologic effect of the vitamin A acid is discussed.