A
monoclonal antibody (MAb), designated
B72.3, has been generated using membrane-enriched fractions of a metastatic human
breast carcinoma as the immunogen. Previous studies have demonstrated that the reactive
antigen, a novel Mr 220,000 to 400,000
glycoprotein complex, can be detected in
formalin-fixed,
paraffin-embedded tissue sections of human breast and colon
carcinomas, and not in a variety of normal adult human tissues. In this preliminary study, we report that MAb
B72.3 may be used as an adjunct for diagnosis of
adenocarcinoma in cytological preparations of human effusions. Using the
avidin-
biotin complex method of immunoperoxidase staining and
formalin-fixed,
paraffin-embedded cell
suspensions, MAb
B72.3 detected
adenocarcinoma cells in effusions from all of 21 patients with
adenocarcinoma of the breast. No reactivity was demonstrated in any cell type in benign effusions from 24 patients without
cancer, or 13 patients with prior or extant
cancer in other body sites; moreover,
B72.3 showed no reactivity to leukemic or lymphomatous effusions, or apparent mesothelial cells from malignant effusions. MAb
B72.3 also detected
adenocarcinoma cells in cytological effusion specimens from 12 of 12 patients with
adenocarcinoma of the lung and 16 of 16 patients with
adenocarcinoma of the ovary. Thus, these data suggest that the immunocytochemical application of MAb
B72.3 should now be considered as an adjunct in the discrimination of
adenocarcinoma cells from reactive mesothelial cells in the cytological diagnosis of malignant effusions.