Histochemical studies of lectin binding patterns in keratinized lesions, including malignancy

Histochemical detection of lectin binding was carried out using the HRP-conjugated lectin method in hyperkeratinized lesions including leukoplakia, carcinoma in situ, Paget's disease, keratoacanthoma, and condyloma acuminatum. The lectins used for demonstrating sugar residues were: Con A (hexose), PNA and RCA-1 (Gal), DBA and SBA (GalNAc), UEA -1 (Fuc), and WGA (GlcNAc). Lectin binding in normal squamous epithelium showed regional distribution patterns of keratinized, spinous and basal layer types. Histochemical localization of lectin binding was generally at the cellular surface and in the intercellular substance and sometimes in the cytoplasm of normal epithelial cells. Dysplastic cells or carcinoma cell, in contrast, displayed a loss of cellular surface and intercellular staining. Paget's cells were devoid of lectin staining. In keratoacanthoma and condyloma specimens, spinous cells, which were PAS-positive, showed an intense PA/Con A-HRP staining and moderate binding by other lectins, which was somewhat decreased when compared with that in the surrounding intact epithelium. The cytochemical distribution of epithelial lectin binding might be indicative of the expression of normal stratification and keratinocytic differentiation , and the disappearance of this typical epithelial pattern may suggest severe dysplasia and malignancy.