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.