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Cyclooxygenase 2 Expression in Pancreatic Adenocarcinoma and Pancreatic Intraepithelial Neoplasia
An Immunohistochemical Analysis With Automated Cellular Imaging

Anirban Maitra MD, Raheela Ashfaq MD, Carla R. Gunn, Ayman Rahman, Charles J. Yeo MD, Taylor A. Sohn MD, John L. Cameron MD, Ralph H. Hruban MD, Robb E. Wilentz MD
DOI: http://dx.doi.org/10.1309/TPG4-CK1C-9V8V-8AWC 194-201 First published online: 1 August 2002


We immunohistochemically examined material from 36 pancreata (adenocarcinomas, 30 lesions; pancreatic intraepithelial neoplasia [PanIN], 65; normal pancreatic ducts, 30) for cyclooxygenase 2 (COX-2) with an automated platform. We analyzed 7 to 10 discrete foci and generated an average percentage of positive cells and average staining intensity for each lesion. These 2 values were then multiplied to create an overall “HistoScore” for each lesion. COX-2 demonstrated considerable heterogeneity of expression between and within cases. The overall average percentage of positive cells in adenocarcinomas was 47.3%; in PanINs, 36.3%; and in normal ducts, 19.2%. COX-2 was expressed in more than 20% of cells in 23 adenocarcinomas (77%), 42 PanINs (65%), and 12 normal ducts (40%). The overall average HistoScore for adenocarcinomas was 6.1; for PanINs, 5.4; and for normal ducts, 3.5. Significant differences in COX-2 expression were demonstrable in adenocarcinomas vs normal ducts, PanINs vs normal ducts, and PanIN 2/3 vs PanIN 1a/1b. In general, the pattern of COX-2 expression increased from normal to PanIN to adenocarcinoma. The up-regulation of COX-2 in a subset of noninvasive precursor lesions makes it a potential target for chemoprevention with selective COX-2 inhibitors.

Key Words:
  • Cyclooxygenase 2
  • Pancreatic adenocarcinoma
  • PanIN
  • Pancreatic intraepithelial neoplasia
  • Image analysis