HBME-1 is an anti-mesothelial cell monoclonal antibody derived from hu
man mesothelioma cells, We investigated 227 body cavity effusions to t
est its utility in differentiating mesothelioma from adenocarcinoma. H
BME-1 outlined cell membranes in non-neoplastic mesothelial cells. Thi
ck surface staining was observed on all mesotheliomas. HBME-1 reactivi
ty was also detected in 24% of metastatic carcinomatous effusions, Mos
t ovarian carcinomas (83%) reacted with this antibody, showing surface
staining, Cytoplasmic HBME-1 immunoreactivity was observed in a small
proportion of non-ovarian adenocarcinomas (14%). Despite its limited
specificity, HBME-1 might be added to the battery of other markers of
epithelial and/or mesothelial differentiation to be used in cases of s
uspected mesothelioma, Evaluation of suspicious cells should include c
areful study of the pattern of immunostaining.