Localisation of COX-2 protein is different in breast ductal carcinoma and adjacent non-tumour ductal epithelium

Clin Transl Oncol. 2005 Jul;7(6):239-43. doi: 10.1007/BF02710169.

Abstract

Introduction: A number of findings suggest that cyclooxygenase-2 (COX-2) is overexpressed in breast tumours. However, there is a lack of consensus in the literature regarding the pattern of expression of this protein in invasive breast ductal carcinoma and in the adjacent non-tumour ductal epithelium. This study compares the expression of COX-2 mRNA and protein in breast ductal carcinoma relative to non-tumour breast tissue.

Material and methods: We analysed the expression of COX-2 mRNA by quantitative PCR, and COX-2 protein by immunohistochemistry in invasive ductal carcinoma as well as in non-tumour adjacent ductal epithelium from 34 breast biopsies diagnosed as being invasive ductal carcinoma. As control, we analysed expression of COX-2 protein by immunohistochemistry in surgically-resected benign breast lesions.

Results: Our results show that COX-2 mRNA and protein are overexpressed in non-tumour ductal epithelium compared with invasive ductal carcinoma. However, the pattern of the protein expression is different in tumour and non-tumour tissue: COX-2 protein is expressed predominantly in the membrane of the non-tumour ductal epithelium (including in benign breast lesions) while, in invasive ductal carcinoma cells, it is localised in the cytoplasm.

Conclusions: The non-tumour ductal epithelium adjacent to invasive ductal carcinoma shows a higher COX-2 expression than does the invasive ductal carcinoma. However, the different localisation of the immunohistochemically-detected protein suggests a possible post-translational regulation of the protein.

MeSH terms

  • Adult
  • Aged
  • Breast / metabolism*
  • Breast / pathology
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Carcinoma, Ductal, Breast / metabolism*
  • Carcinoma, Ductal, Breast / pathology
  • Epithelium / metabolism
  • Epithelium / pathology
  • Female
  • Humans
  • Immunohistochemistry
  • Middle Aged
  • Polymerase Chain Reaction
  • RNA, Messenger / analysis

Substances

  • RNA, Messenger