Loss of epithelial blood group antigens A and B in oral premalignant lesions.

Tissue from 40 oral premalignant lesions were investigated for the presence of blood group antigens A and B. The material included 18 leukoplakias, 1 erythroplakia, and 3 lichen planus, all with varying degrees of epithelial dysplasia, and 18 leukoplakias without histological evidence of impending malignancy. Thirty-eight benign keratotic oral muscosal lesions were included as a control group. The antigens were demonstrated by a double layer immunofluorescence technique, and the reactivity was compared, by titration, to the reactivity of adjacent normal epithelium from the same patient. All 22 lesions with dysplsia showed decreased reactivity for blood group antigen. Among the 18 leukoplakias without any signs of impending malignancy 4 cases demonstrated loss of antigen reactivity. None of 38 benign control lesions showed any change in antigen reactivity as compared to normal adjacent epithelium.