title: Over-expression of COX-2 mRNA in colorectal cancer.
abstract: BACKGROUND
  Cyclooxygenase-2 (COX-2, PTGS2) is an enzyme involved in the synthesis of prostaglandins and thromboxanes, which are regulators of biologic processes such as inflammation, cell proliferation and angiogenesis. COX-2 over-expression was reported in many (pre) malignant tissues, but data strongly vary and seem to depend on the methodology used.
  
  
  METHODS
  Normal colorectal mucosa and paired cancerous tissue from 60 patients with colorectal cancer was investigated for the levels of COX-2 mRNA by real-time quantitative Polymerase Chain Reaction (qPCR). COX-2 levels were expressed relative to either: tissue weight or levels of the housekeeping genes beta-2 microglobulin (B2M) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH).
  
  
  RESULTS
  COX-2 mRNA levels, normalized with respect to tissue weight or mRNA levels of the housekeeping genes B2M or GAPDH, were over-expressed in 80%, 70% and 40% of the colorectal tumor tissues, as compared to the paired adjacent normal colorectal mucosa samples, respectively. Highest mRNA COX-2 ratios tumor/normal were measured when expressed per mg tissue (mean ratio 21.6). When normalized with respect to the housekeeping genes B2M or GAPDH, mean tumor/normal ratios were 16.1 and 7.5, respectively.
  
  
  CONCLUSIONS
  Expression of COX-2 mRNA levels per mg tissue is most simple in comparison to normalization with respect to the housekeeping genes B2M or GAPDH. Levels of COX-2 mRNA are found over-expressed in almost 80% of the colorectal tumors, compared to paired adjacent normal colorectal mucosa, suggesting a role of COX-2 as a potential biomarker for cancer risk, whereas inhibitors of COX-2 could be of value in chemoprevention of colon cancer.
authors.forename: Hennie M J
authors.initials: HM
authors.lastname: Roelofs
authors.forename: Rene H M
authors.initials: RH
authors.lastname: Te Morsche
authors.forename: Bjorn W H
authors.initials: BW
authors.lastname: van Heumen
authors.forename: Fokko M
authors.initials: FM
authors.lastname: Nagengast
authors.affiliation: Department of Gastroenterology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands. w.peters@mdl.umcn.nl.
authors.forename: Wilbert H M
authors.initials: WH
authors.lastname: Peters
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics*; D002277:Carcinoma / Q000201:enzymology / Q000235:genetics*; D015179:Colorectal Neoplasms / Q000201:enzymology / Q000235:genetics*; D051546:Cyclooxygenase 2 / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D005819:Genetic Markers; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D006801:Humans; D007413:Intestinal Mucosa / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism*; D055815:Young Adult; D001613:beta 2-Microglobulin / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; D005819:Genetic Markers; D012333:RNA, Messenger; D001613:beta 2-Microglobulin; D051546:Cyclooxygenase 2; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases