Selection of carbohydrate antigens in human epithelial ovarian cancers as targets for immunotherapy: Serous and mucinous tumors exhibit distinctive patterns of expression

Expression of blood group-related carbohydrate antigens was examined in fro zen sections from a series of ovarian carcinomas of different histological types using an indirect immunoperoxidase technique. Antigenic specificities belonging to the O(H) and Lewis blood group families (H-1, H-2, Le(a), sLe (a), Le(x), sLe(x), Le(b) and Le(y)) or the mucin-core family (Tn, sTn and TF) were studied. A distinct difference in antigen expression between mucin ous and other ovarian carcinomas (serous and endometrioid) was observed. Sp ecifically, mucinous tumors tended to express sTn, Le(a) and sLe(a) strongl y and homogeneously, whereas serous and endometrioid tumors rarely expresse d these specificities and, in contrast, expressed Le(y) and H type 2 antige n strongly. When expressed in serous tumors, sTn was usually distributed in a heterogeneous pattern, whereas sTn expression in mucinous tumors was muc h more homogeneous. The distribution of Le(y) in serous tumors was noticeab ly homogeneous. H-1, Le(x), sLe(x), Le(b), TF and Tn specificities were rar ely expressed in any type of ovarian carcinoma. Our results provide further support for the different histogenesis of mucinous and non-mucinous tumors and indicate alternative differentiation pathways for the 3 pathological s ubtypes of ovarian tumor. They also provide the basis for the choice of car bohydrate antigens for active and passive immunotherapy of ovarian carcinom as. Int. J. Cancer 81:193-198, 1999, (C) 1999 Wiley-Liss, Inc.