Overexpression of cyclooxygenase-2 in carcinoma of the pancreas.

The level of cyclooxygenase (COX)-2 has been investigated recently in various human carcinomas. In the present study, we examined the distribution and extent of COX-2 protein in human pancreatic tumors using immunohistochemistry. A strong expression of COX-2 protein was present in 23 of 52 (44%) pancreatic carcinomas, a moderate expression was present in 24 of 52 (46%) pancreatic carcinomas, and a weak expression was present in 5 of 52 (10%) pancreatic carcinomas. In contrast, benign tumors showed weak expression or no expression of COX-2, and only islet cells displayed COX-2 expression in normal pancreatic tissues. Overexpression of COX-2 in carcinoma tissues was also confirmed by Western blot analysis. Furthermore, consistent with the results at protein levels, reverse transcription-PCR analyses indicated that COX-2 mRNA was overexpressed in 7 of 13 (54%) carcinomas, but in none of 3 benign tumors. Our findings suggest that COX-2 inhibitors might be potentially effective against pancreatic carcinomas and that COX-2 may be involved in certain biological processes in pancreatic islets.