As p53 expression has been associated with malignant disease its presence was assessed in biopsy specimens from dorsal lingual hyperkeratosis, taken over a five year period. p53 expression, using CM1, was assessed using a standard immunoperoxidase technique. p53 was not identified in the first biopsy specimen in 1986 but was identified in all subsequent ones. Only in the latest biopsy specimen was there evidence for dysplasia in haematoxylin and eosin stained sections. It is suggested that p53 expression may be a reliable marker for predicting premalignant change in keratoses occurring in dyskeratosis congenita.