口腔粘膜白板症の免疫組織化学的研究

Abstract

The present study deals with 114 cases of oral leukoplakia and clinicopathological findings evaluated with respect to epithelial differentiation and keratinization using keratin antibodies, expression of epidermal growth factor receptor (EGF-r), and proliferating cell nuclear antigen (PCNA). Oral leukoplakias were most often found in men (57%) and women (43%) aged 40-60 years. The commonest sites were the gingiva (32.4%), tongue (25.4%), and cheek (23.7%). Hyperorthokeratinization of the epithelium was most commonly seen in the masticatory mucosa (gingiva and hard palate) and hyperparakeratinization in non- or lesskeratinized mucosa (buccal mucosa and floor of the mouth). Epithelial dysplasia was observed in 19 cases (tongue 9, buccal mucosa 5, gingiva 3, palate 2). Cytokeratins (CK) detected by polyclonal TK were present in all epithelial layers except the keratinized layer; CK detected by monoclonal KL 1 in the spinous and granular cell layer; K8.12 in the spinous layer; and PKK 1 in the basal layer. Involucrin was present in the upper-spinous and granular cell layer and filaggrin in the granular cell and hyperkeratinized layer. EGF-r was detected in the basal and spinous cell, and dysplastic cells were unreactive. PCNA immunoreactivity was distributed in the basal and suprabasal cells. Leukoplakia on the lateral border of the tongue was characterized by a lesser degree of hyperkeratinization but with an increased frequency of epithelial dysplasia. Leukoplakia on the gingiva and hard palate, on the other hand, had more advanced hyperorthokeratinization, but epithelial dysplasia was rarely observed. The hyperkeratinization in oral leukoplakia is influenced primarily by sitewise variations in keratinization of the normal oral mucosa and less frequently by the extent of epithelial dysplasia.