Carcinoma‐associated cytostructural antigenic alterations: Detection by lectin binding

Tumor cell membrane glycoproteins may be involved in the induction of tumor immunity or in the escape of tumors from immunologic defense mechanisms. Previous investigations have suggested a role for blood group antigens and their precursors, in the generation of the immune response to neoplasia. In this study, 44 benign and malignant breast lesions were examined for the presence of a carbohydrate precursor antigen (T‐antigen) of the human blood group system MN. T‐antigen was demonstrated using an immunohistochemical technique to detect tissue binding of a plant lectin (PNA) with specificity for T‐antigen. Of the 22 benign breast lesions examined, 19 showed T‐antigen present along the luminal cytoplasmic membrane and occasionally on intraluminal secretions. T‐antigen, as demonstrated by lectin binding, was confined to this region in all benign lesions except one, which also showed cytoplasmic positivity. Malignant breast lesions showed a pattern of T‐antigen expression markedly different from that of benign breast tissues. Of 22 breast carcinomas, 17 showed diffuse cytoplasmic T‐antigen. Five carcinomas showed no evidence of T‐antigen by this technique. These malignancies tended to be the most poorly differentiated when judged by histologic criteria. A possible role for T‐antigen in the modulation of the immune response to breast carcinoma is suggested.