Keratin and involucrin in preneoplastic and neoplastic lesions. Distribution in the nasal mucosa of nickel workers.

Nasal mucosal biopsy specimens encompassing normal and pathological epithelia were obtained from nickel workers, a population with an increased incidence of carcinomas of the respiratory tract. The immunohistochemical detection of keratins was carried out using monoclonal antibodies AE1 and AE3. The antibody AE1 stained only the basal cells of normal mucociliary epithelium. Regular metaplasias showed an increased stain with AE3; all layers of the surface epithelium were stained. The dysplastic and neoplastic lesions exhibited an extraordinary increase in the staining patterns with AE3 and to a lesser extent with AE1. Involucrin, which was absent from the normal pseudostratified epithelium, appeared in all metaplastic-dysplastic lesions and in keratinized areas of carcinomas. The combined detection of keratins and involucrin proved useful in detecting the degree of maturity and differentiation of preneoplastic and neoplastic lesions of the nasal mucosa.