Detection of neutral endopeptidase 24.11 (neprilysin) in human hepatocellular carcinomas by immunocytochemistry.
BACKGROUND
We have reported previously that neutral endopeptidase 24.11 (neprilysin; NEP; CALLA, CD10) activity was very high in rat hepatomas and a cultured human hepatocarcinoma cell line (SK-HEP1).


METHODS
While continuing these studies, we detected the presence of NEP in SK-HEP 1 cells by immunocytochemistry and in paraffin-embedded human hepatocellular carcinomas as well. IgG purified from polyclonal antisera to human NEP was employed as a source of antibody.


RESULTS
SK-HEP 1 cells gave a strong positive reaction to the IgG fraction of the antisera. In control studies, where IgG was preabsorbed with recombinant NEP, the results were negative. Of the 18 hepatocellular carcinomas tested, NEP was expressed in 14 (78%) malignant tumors, while adjacent liver tissue did not show the presence of NEP.


CONCLUSIONS
It is suggested that, because none of the known hepatocellular carcinoma markers are highly specific, the detection of NEP in these malignant cells can be an additional useful diagnostic tool.
Dragovic
T
T
Department of Pharmacology, University of Illinois College of Medicine, Chicago 60612, USA.
Sekosan
M
M
Becker
R P
RP
Erdös
E G
EG
D000230:Adenocarcinoma / Q000201:enzymology; D014408:Biomarkers, Tumor; D006528:Carcinoma, Hepatocellular / Q000201:enzymology*; D018281:Cholangiocarcinoma / Q000201:enzymology; D018240:Endodermal Sinus Tumor / Q000201:enzymology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008099:Liver / Q000201:enzymology; D008113:Liver Neoplasms / Q000201:enzymology*; D008297:Male; D015260:Neprilysin / Q000378:metabolism*; D010190:Pancreatic Neoplasms / Q000201:enzymology; D014407:Tumor Cells, Cultured
D014408:Biomarkers, Tumor; D015260:Neprilysin