CD24 is a marker for human breast carcinoma

CD24 is a small, mucin-type glycosylphosphatidylinositol-linked cell surfac e molecule expressed by neutrophils, pre B lymphocytes and certain human tu mor cell lines. CD24 has been identified as a ligand for P-selectin in both mouse and human cells. We previously reported that the P-selectin-CD24 bin ding pathway is important for the binding of the breast carcinoma cell line KS to platelets and the rolling of these cells on endothelial P-selectin. In the present study we have analyzed the expression of CD24 on human breas t carcinoma cell Lines and on fresh breast carcinoma specimens using the CD 24-specific antibody ML-5, Our study clearly demonstrates that CD24 is abun dantly expressed on cell lines and fresh tissues of breast carcinomas. We f ind a differential expression of CD24 in breast carcinomas (cytoplasmic pat tern) versus benign breast lesions (apical pattern). Moreover, the intensit y of CD24 expression increases with the histological grade of the tumor. Th us, CD24 expression might be a useful marker for human breast carcinoma and play a role in facilitating metastasis by the interaction between tumor ce lls and platelets or endothelial cells. (C) 1999 Elsevier Science Ireland L td. All rights reserved.