EXPRESSION OF A B-CELL MARKER, CD24, ON NASOPHARYNGEAL CARCINOMA-CELLS

Random sequencing of clones from a lambda gt10 cDNA library, made from mRNA expressed in an Epstein-Barr virus (EBV)associated nasopharyngea l carcinoma (NPC) has revealed the gene transcript of human CD24. The CD24 antigen, a glyco-sylphosphatidylinositol-anchored cell surface mo lecule, has been identified as a B-cell marker that is lost during cel l maturation. We show here that it is expressed on 3 NPC xenografts, p reviously defined as consisting of poorly differentiated epithelial ce lls, and on an NPC biopsy. In the case of the former, the level of exp ression of CD24 corresponds to the EBV load. A B-lymphoblastoid cell l ine carrying the same EBV genome as one of the tumours, C15, and an EB V-negative Burkitt's lymphoma cell line do not display the antigen, bu t epithelial-like cells of a laryngeal tumour cell line (Hep2) do expr ess it. Our data suggest that CD24 may be a marker of cell differentia tion not only for B cells but also for epithelial cells and may have a n indirect association with EBV gene expression. (C) 1995 Wiley-Liss, Inc.