Specific Role of T and Tn Tumor‐associated Antigens in Adhesion between a Human Breast Carcinoma Cell Line and a Normal Human Breast Epithelial Cell Line

The possibility that tumor‐associated antigens T and Tn act as adhesion molecules between normal and malignant breast epithelial cells at the early stages of recognition in the metastatic pathway was examined in vitro. The adhesive specificity of the antigens was assessed by means of in vitro adhesion tests between a carcinomatous breast cancer cell line (ZR75‐30) and a normal epithelial breast cell line (HLB100) using both monoclonal antibodies and lectins specific as well as nonspecific for each antigen. Adhesion assay was performed using monolayers of the normal cell line prepared on plastic culture plates and the tumor cell line labeled with a fluorescent dye as a probe. The adhesion between the two cell types occurred with significant specificity via T and Tn antigens (P < 0.001), and was temperature‐dependent. The results suggest that at the early stages of recognition by tumor cells in the metastatic process, T and Tn antigens play a role as adhesion molecules between the tumor cells and adjacent normal cells.