involucrin and Conjunctival-Neoplasms

Keratinization of the ocular surface epithelium is associated with various disorders impairing vision. We immunohistochemically determined whether the ocular surface epithelia express involucrin, and whether its expression pattern may differ in benign vs. malignant disorders. Expression of cytokeratins was also examined to provide further information relative to the epithelial differentiation.. We evaluated 17 specimens; 6 specimens of the normal ocular surface epithelia, 3 specimens from cases of conjunctival intraepithelial neoplasia (CIN), 6 of conjunctival squamous cell carcinoma (SCC) and 2 of conjunctivae from cases of superior limbic keratoconjunctivitis (SLK).. Corneal epithelium exhibited intracellular immunoreactivity for involucrin. Four of the 6 specimens of bulbar conjunctival epithelium showed involucrin immunoreactivity in the perimembranous region, whereas the fornical conjunctiva was negative. Cornified envelope in SLK specimens was positive for involucrin. The CIN showed its immunoreactivity in the perimembranous region in all levels of the hyperproliferative epithelium without keratinization, i.e., similar to the bulbar conjunctiva. The neoplastic cells of well-differentiated SCC showed involucrin in the perimembranous region, and those of moderately- to poorly-differentiated SCC have involucrin in their cytoplasm. The expression pattern of cytokeratins was unrelated to grade of malignancy in ocular SCC.. The epithelia of normal subjects and of CIN expresses involucrin without keratinization. In contrary, the keratinized SLK epithelium markedly expresses involucrin in the cornified envelope. The subcellular immunolocalization of involucrin in the ocular SCC may help in evaluating the differentiation, i.e., malignancy, of neoplastic cells.

Topics: Adult; Aged; Aged, 80 and over; Carcinoma in Situ; Carcinoma, Squamous Cell; Conjunctiva; Conjunctival Diseases; Conjunctival Neoplasms; Epithelium; Eye Proteins; Female; Filaggrin Proteins; Humans; Immunoenzyme Techniques; Intermediate Filament Proteins; Keratins; Keratoconjunctivitis; Male; Middle Aged; Protein Precursors

Involucrin is a precursor of the cross-linked envelope protein of the human stratum corneum. Its appearance in the upper layers of the epidermis reflects normal differentiation of keratinocytes. This study uses an immunoperoxidase technique for localization of involucrin in paraffin sections of normal conjunctiva, conjunctival dysplasia, carcinoma in situ, and invasive carcinoma. Clinicoimmunocytochemical correlations are presented. The results demonstrate that the distribution patterns of involucrin differ in precancerous and cancerous conjunctival lesions: normal limbal conjunctiva shows involucrin only in the three superficial cell layers; the fornix conjunctivae contains no involucrin. All 23 conjunctival dysplasias show an involvement also of deeper layers of the epithelium, sparing the basal layers. Three carcinomas in situ and one invasive squamous cell carcinoma, however, demonstrate an involvement of all layers of the epithelium. The involucrin staining pattern helps in histologic differential diagnosis of epithelial lesions of the conjunctiva.

Topics: Biopsy; Carcinoma; Carcinoma in Situ; Carcinoma, Squamous Cell; Conjunctiva; Conjunctival Neoplasms; Epithelium; Humans; Immunoenzyme Techniques; Neoplasm Invasiveness; Precancerous Conditions; Protein Precursors