title: Immunohistochemical assessment of human microsomal epoxide hydrolase in primary and secondary liver neoplasm: a quantitative approach.
abstract: 1. Epoxide hydrolases form an enzyme family involved in the metabolism of a variety of xenobiotics including cytostatic drugs and carcinogens. Whether human microsomal epoxide hydrolase--one of the main members of the epoxide hydrolase family--is expressed in neoplasia of the liver has been the subject of a controversial discussion. 2. We therefore developed a quantitative immunohistochemical assay and monitored epoxide hydrolase expression in hepatocellular carcinomas (HCC, n = 20), cholangio-cellular carcinomas (CCC, n = 2) and liver metastases (n = 57) of tumours of various origins, and compared the expression intensities and patterns to normal liver tissue. 3. In normal liver tissue microsomal epoxide hydrolase displays expression of the constitutive type with non-zonal staining of all hepatocytes. 4. When using a quantitative immunohistochemical approach statistically significant differences in microsomal epoxide hydrolase expression were observed between normal tissue, hepatocellular carcinoma and liver metastases (mean optical density 2.35, 1.63 and 0.21 respectively, p = 2.9, 6.3 and 18.9). These data indicate differential expression in different types of liver neoplasm. 5. As microsomal epoxide hydrolase is involved in metabolism of different xenobiotics our findings may have implications for tumour progression.
authors.affiliation: Zentrum für Klinische Pathologie, Robert Bosch Krankenhaus, Stuttgart, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Fritz
authors.forename: E
authors.initials: E
authors.lastname: Behrle
authors.forename: U M
authors.initials: UM
authors.lastname: Zanger
authors.forename: T
authors.initials: T
authors.lastname: Mürdter
authors.forename: P
authors.initials: P
authors.lastname: Schwarzmann
authors.forename: H K
authors.initials: HK
authors.lastname: Kroemer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000201:enzymology / Q000648:ultrastructure; D004851:Epoxide Hydrolases / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008113:Liver Neoplasms / Q000201:enzymology* / Q000556:secondary / Q000648:ultrastructure; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D008875:Middle Aged; D015262:Xenobiotics / Q000378:metabolism
chemical_list: D015262:Xenobiotics; D004851:Epoxide Hydrolases