Cyclooxygenase-2 expression in normal ovaries and epithelial ovarian neoplasms

Cyclooxygenase-2 (COX-2) expression was investigated immunohistochemically in 57 epithelial ovarian neoplasms and in histologically normal ovaries. Positive immunostaining for COX-2 was observed in 78.6% (22/28) of the ovarian cancers and in 66.7% (14/21) of the borderline-malignant tumors. The rate of expression was significantly higher among the ovarian cancers than the benign cystadenomas (4/8; 50%) (p<0.05). There was a significant correlation between vascular endothelial growth factor (VEGF) expression and microvessel count (MVC), but no correlation between COX-2 expression and MVC. There was a significant correlation between VEGF expression and COX-2 expression in all of the ovarian neoplasms as a whole (p<0.05). These findings suggest that an increase in COX-2 expression may be associated with malignant transformation and tumorigenesis of epithelial ovarian neoplasms.