Localization of cyclooxygenase-2 in human sporadic colorectal adenomas

Am J Pathol. 2000 Feb;156(2):545-53. doi: 10.1016/S0002-9440(10)64759-1.


A putative target for the anti-colorectal cancer action of nonsteroidal anti-inflammatory drugs is the inducible isoform of cyclooxygenase (COX), COX-2. COX-2 is expressed within intestinal adenomas in murine polyposis models, but expression has been poorly characterized in human colorectal neoplasms. Therefore, we investigated the localization of the COX-2 protein in human sporadic colorectal adenomas. Immunohistochemistry for COX-2 and CD68 (a tissue macrophage marker) was performed on formalin-fixed, paraffin-embedded (n = 52) and frozen, acetone-fixed (n = 6) sections of human sporadic colorectal adenomas. Forty of 52 (77%) formalin-fixed adenomas expressed immunoreactive COX-2. COX-2 was localized to superficial interstitial macrophages in 39 cases (75%) and to deep interstitial macrophages in 9 cases (17%). COX-2 staining of dysplastic epithelial cells was observed in 15 cases (29%). A logistic regression analysis identified the adenoma site (P = 0.012) and histological type (P = 0.001) as independent predictors of superficial macrophage COX-2 expression. There was no relationship between the number of macrophages within an adenoma and macrophage COX-2 expression. These results indicate that COX-2 is expressed predominantly by interstitial macrophages within human sporadic colorectal adenomas. If COX-2 does indeed play a role in the early stages of colorectal carcinogenesis in man, these data suggest COX-2-mediated paracrine signaling between the macrophages and epithelial cells within adenomas.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoma / enzymology*
  • Colorectal Neoplasms / enzymology*
  • Cyclooxygenase 2
  • Fluorescent Antibody Technique, Indirect
  • Humans
  • Immunohistochemistry
  • Isoenzymes / metabolism*
  • Membrane Proteins
  • Prostaglandin-Endoperoxide Synthases / metabolism*
  • Tissue Distribution


  • Isoenzymes
  • Membrane Proteins
  • Cyclooxygenase 2
  • PTGS2 protein, human
  • Prostaglandin-Endoperoxide Synthases