The Role of Cyclooxygenase - 2 Expression in Pancreatic Cancer

Lee, Yong Wook; Lee, Kyu Taek; Lee, Jun Haeng; Park, Dong Il; Lee, Jong Kyun; Rhee, Poong Lyul; Kim, Jae J; Koh, Kwang Cheol; Paik, Seung Woon; Rhee, Jong Chul; Choi, Kyoo Wan; Kim, Wan Sun; Kim, Eun Kyung; Gong, Gu

Abstract

BACKGROUND/AIMS: Accumulating evidence suggests that the use of NSAID may reduce the incidence of colorectal cancer. The likely mechanisms of these effects by NSAID is cyclooxygenase-2 (COX-2)-related inhibition of tumor proliferation and induction of apoptosis. The aim of our study was to examine possible roles and clinical significance of COX-2 expression in pancreatic cancer.
METHODS
Seventy-two pancreatic adenocarcinoma tissue specimens were obtained from surgical resection. After the immunohistochemical staining of the specimens, we examined proliferation activity (assayed by Ki-67 expression), apoptosis (by TUNEL stain), and microvessel density (by CD34 expression). We also investigated the relationship between the immunohistochemical expression of COX-2 and various clinicopathological characteristics.
RESULTS
The COX-2 positive rate in pancreatic epithelial cells was 41.7%. Proliferation index (PI) was significant higher in COX-2 positive specimens comparing to negative specimen (p=0.015) and the increase in intensity of COX-2 expression correlated with increasing PI (p=0.036). Apoptotic index (AI) was significantly higher in positivee COX-2 expression than in negative expression (p=0.044), but there was no significant difference in AI/PI between the COX-2 positive and negative specimens (p=0.44). The expression of COX-2 protein did not correlate with microvessel density, sex, age, differentiation, tumor size, stage, metastasis or patients survival.
CONCLUSIONS
The expression of COX-2 enzyme in pancreatic cancer contributes to tumor proliferation, but is not related to apoptosis, angiogenesis or clinical characteristics. Further study is needed to examine the clinical usefulness of NSAID and COX-2 selective inhibitors.