Cyclooxygenase-2 expression in gastroenteropancreatic neuroendocrine tumors

The aim of this multicenter study was to investigate cyclooxygenase-2 protein expression in gastroenteropancreatic neuroendocrine tumors and to examine the relationship to various clinicopathological parameters.

Thirty-seven gastroenteropancreatic neuroendocrine tumor specimens were analyzed immunohistochemically. Correlations between expression and some parameters such as age, sex, tumor size, location, presence of multiple neuroendocrine tumor, lymphatic/vascular/muscularis propria invasion and lymph node metastases were evaluated. Results were interpreted as significant if p < 0.05.

Mean age of patients (15 men/22 women) was 52 +/- 17. Tumor size varied between 0.1 and 12 cm. (mean; 3.17 +/- 3.29 cm). Expression was detected in 75% of cases and in 92% of gastric neuroendocrine tumors. Expression in mixed endocrine and non-endocrine carcinomas was found to be significantly higher than in well-differentiated neuroendocrine tumors and carcinomas (p = 0.016). A relationship was observed between overexpression and lymphatic and vascular invasion (p = 0.029). However, no significant correlation was found between expression and sex, tumor location, size, muscularis propria invasion and lymph node metastasis.

Cyclooxygenase-2 expression may play a role in the evolution of gastroenteropancreatic neuroendocrine tumors. However, further studies are necessary to determine the importance of this role, prognostic relevance and whether cyclooxygenase isoenzyme can be a target for treatment in these tumors.