title: Cyclooxygenase-2 expression in hepatocellular carcinoma.
abstract: OBJECTIVE
  Cyclooxygenase-2 (Cox-2) is an isoform of cyclooxygenase, which is the key enzyme converting arachidonic acids to prostaglandins. It has been reported that Cox-2 is overexpressed in colon cancer, and that inhibition of this enzyme activity reduces colon cancer development in humans and animals. However, the significance of Cox-2 in human liver cancer is still unclear. To clarify significance of Cox-2 in liver cancer, we immunohistochemically examined expression of this enzyme in cancerous and non-cancerous tissues of hepatocellular carcinoma (HCC).
  
  
  METHODS
  Twenty-nine patients with HCC were examined; 10 patients had well differentiated HCC, 10 had moderately differentiated HCC, and 9 had poorly differentiated HCC.
  
  
  RESULTS
  Twenty-eight of 29 (97%) patients with HCC exhibited a positive staining. More intense staining of Cox-2 in cancer tissue rather than non-cancerous tissue was observed in 7 of 10 (70%) patients with well differentiated HCC, in 3 of 10 (30%) with moderately differentiated HCC, and in 3 of 9 (33%) with poorly differentiated HCC, respectively. Rate of higher expression of Cox-2 in cancer tissue rather than in non-cancerous tissue of well differentiated HCC was increased, compared to that of moderately and poorly differentiated HCC (7/10 vs. 6/19, p < 0.05).
  
  
  CONCLUSIONS
  The results of the present study showed that Cox-2 is related to HCC whose histology is well differentiated.
authors.affiliation: Second Department of Internal Medicine, Tottori University School of Medicine, Yonago, Japan. gshiota@grape.med.tottori-u.ac.jp
authors.forename: G
authors.initials: G
authors.lastname: Shiota
authors.forename: M
authors.initials: M
authors.lastname: Okubo
authors.forename: T
authors.initials: T
authors.lastname: Noumi
authors.forename: N
authors.initials: N
authors.lastname: Noguchi
authors.forename: K
authors.initials: K
authors.lastname: Oyama
authors.forename: Y
authors.initials: Y
authors.lastname: Takano
authors.forename: K
authors.initials: K
authors.lastname: Yashima
authors.forename: Y
authors.initials: Y
authors.lastname: Kishimoto
authors.forename: H
authors.initials: H
authors.lastname: Kawasaki
mesh_terms: D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000201:enzymology* / Q000473:pathology; D002454:Cell Differentiation; D051546:Cyclooxygenase 2; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism*; D008113:Liver Neoplasms / Q000201:enzymology* / Q000473:pathology; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D008565:Membrane Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases