Immunoreactivity for BER-EP4 in adenocarcinomas, adenomatoid tumors, and malignant mesotheliomas.
Ber-EP4 is a recently characterized monoclonal antibody directed against a cell surface glycoprotein that is putatively present on human epithelial cells but lacking on the mesothelium. To investigate the diagnostic efficacy of Ber-EP4 in distinguishing adenocarcinoma from mesothelioma, we studied formalin-fixed, paraffin-embedded sections from well-documented cases of adenocarcinoma (120 cases), adenomatoid tumor (nine cases), and malignant mesothelioma (49 cases). Of the 120 adenocarcinomas, 103 (86%) showed membranous Ber-EP4 positivity, with diffuse reactivity noted in 82 cases and focal staining in 21 cases. Reactivity with Ber-EP4 was also observed in two of nine adenomatoid tumors (22%) and 10 of 49 mesotheliomas (20%). Staining in the mesotheliomas was restricted to epithelioid areas and generally focal. In one mesothelioma, however, Ber-EP4 stained the majority of neoplastic cells. In contrast to previous reports, we conclude that positivity with Ber-EP4 does not exclude the diagnosis of mesothelioma. Nonetheless, most Ber-EP4-positive mesotheliomas exhibit only focal positivity, as opposed to the extensive staining commonly observed in adenocarcinomas. Ber-EP4 has diagnostic utility in the discrimination of mesothelioma from adenocarcinoma, but it is best utilized in an antibody panel that includes other markers of carcinomatous differentiation.
Gaffey
M J
MJ
Department of Pathology, University of Virginia Health Sciences Center, Charlottesville 22908.
Mills
S E
SE
Swanson
P E
PE
Zarbo
R J
RJ
Shah
A R
AR
Wick
M R
MR
D000230:Adenocarcinoma / Q000175:diagnosis* / Q000473:pathology; D000911:Antibodies, Monoclonal; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry; D008654:Mesothelioma / Q000175:diagnosis* / Q000473:pathology
D000911:Antibodies, Monoclonal; C117805:Ber-EP4 monoclonal antibody