Alterations in glycoconjugate expression following malignant transformation of human oropharyngeal squamous mucosa

Malignant transformation of the squamous mucosa in the human oropharynx may be accompanied by alterations in carbohydrate production. Glycoconjugate expression was assessed by examining lectin-binding patterns and ABH isoantigen expression in human biopsy specimens from nine cases of carcinoma in situ and ten cases of invasive squamous cell carcinoma as well as adjacent normal squamous mucosa. Ten different fluorescein-conjugated lectins were used. Each lectin binds to specific nonreducing end-terminal carbohydrate residues. Wheat germ agglutinin and peanut agglutinin displayed intense cytoplasmic and/or membrane binding in more than 90% of the carcinoma in situ and squamous cell carcinoma specimens. However, only 40% of normal squamous epithelium specimens displayed intense cytoplasmic and/or membrane binding with wheat germ agglutinin and peanut agglutinin. Bandieraea simplicifolia I and Helix pomatia exhibited weak binding in less than 35% of normal and neoplastic tissues. Weak canavalia ensiformis binding was identified infrequently in the superficial layers of normal squamous mucosa, but was not found in neoplastic epithelium. None of the cases displayed binding for Dolichos biflorus, Ulex europaeus I, Sophora japonica, Glycine maximus, or Ricinus communis. Monoclonal antibodies directed against ABH blood group isoantigens showed increased cytoplasmic immunoreactivity for anti-H in dysplastic and neoplastic tissues, when compared with normal squamous mucosa. These findings indicate that wheat germ agglutinin and peanut agglutinin and H isoantigen are useful markers of malignancy in squamoproliferative lesions of the oropharynx, apparently reflecting alterations in expression of N-acetyl-D-glucosamine and galactose-related sugars, which appear following malignant transformation.