Abstract
The purpose of this study was to establish the criteria for oral epithelial dysplasia (OED). A total of fifty-six biopsies of white lesions in the buccal mucosa and gingiva were classified into Type I, II and III, and their relationship to expression of PCNA or p53 and keratinization patterns were examined. The appearance of PCNA positive cells coincided with severe atypia in the basal layer. p53 expression revealed focal, diffuse and basal layer patterns. The focal pattern was found in only Type I; both the diffuse and basal layer patterns were seen in Type II. All the cases of Type III showed the basal layer pattern. It is suggested that p53 expression of the basal layer pattern is useful for estimating the malignant potency. Parakeratosis demonstrating a tendency toward severe atypism and general disturbance is an important malignant sign.
