Carbohydrate antigen expression in primary tumors, metastatic lesions, andserous effusions from patients diagnosed with epithelial ovarian carcinoma: Evidence of up-regulated Tn and Sialyl Tn antigen expression in effusions

The object of this study was the investigation of carbohydrate antigen expr ession iu malignant epithelial cells and benign mesothelial cells in serous effusions from patients diagnosed with epithelial ovarian carcinomas. In a ddition, to compare antigen expression in carcinoma cells in effusions with those of corresponding primary tumors and metastatic lesions. Sections fro m 63 malignant effusions from ovarian carcinoma patients and 15 reactive ef fusions were immunohistochemically stained, using 5 monoclonal antibodies f or Lewis(y), Sialyl Lewis(x), Tn, and Sialyl Tn antigens. Tissue sections ( n 97) from corresponding primary ovarian carcinomas and metastatic lesions, as well as from 12 malignant mesotheliomas, were additionally stained usin g the above panel. Staining for the 4 antigens was seen in carcinoma cells in serous effusions in the majority of Eases (range = 71% to 85%). In contr ast, immunoreactivity was detected in mesothelial cells in only 6% to 23% o f the specimens studied (P < .001 for all 5 markers). With the exception of B3 antibody against LewisY antigen, malignant mesotheliomas stained negati ve, infrequently showing focal immunoreactivity. An up-regulation of Tn and Sialyl Tn expression was detected in carcinoma cells in effusions when com pared with both primary tumors (P < .003 and P < .007, respectively) and me tastatic lesions (P < .034 and .041, respectively). Cancer-associated carbo hydrate antigens can thus be used as an adjunct in the differentiation betw een malignant epithelial and reactive mesothelial cells. Ovarian carcinoma cells in effusions show up-regulation of Tn and Sialyl Tn, possibly represe nting a transient phenotypic alteration facilitating metastasis. Copyright (C) 2000 by W.B. Saunders Company.