THE BREAST MUCIN MUC1 AS A NOVEL ADHESION LIGAND FOR ENDOTHELIAL INTERCELLULAR-ADHESION MOLECULE-1 IN BREAST-CANCER

The MUC 1 mucin is expressed on normal breast epithelium and in 90% of breast cancers. We report here that tumor-associated MUC1 is a ligand for intercellular adhesion molecule 1 (ICAM-1). Antibodies to ICAM-1 and to MUC1 inhibited adhesion of human and transfected mouse MUC1-pos itive cell lines to human umbilical vein endothelial cell monolayers a nd immobilized recombinant human ICAM-1-immunoglobulin fusion protein, Purified MUC1 pretreatment of recombinant human ICAM-1 aas an equally effective inhibitor of adhesion, The interaction between MUC1 and ICA M-1 may be critical to the process of bloodborne metastases in breast cancer.