Immunocytochemical Diagnosis of Neoplastic Effusions of Unknown Origin Employing Selected Combinations of Monoclonal Antibodies to Tumor-Associated Antigens

Abstract

Malignant cells in metastatic effusions from solid tumors can easily be detected because of their morphologic features, but their histological type can rarely be defined [4]. The recent availability of an increasing number of monoclonal antibodies (MAbs) to tumor-associated antigens (TAA) may offer a powerful diagnostic complement to conventional morphologic diagnosis for the identification of the organ of origin of the primary tumor. In the present study we evaluated whether the use of selected combinations of MAbs to TAAs which lack detectable reactivity with mesothelial cells may provide useful information in the cytodiagnosis of effusions in patients with unknown primary malignancy. The results of this study show that a panel of selected MAbs is a valuable adjunct to routine cytopathology since it enables identification of the site of primary tumors in 87% of the cases studied.