Expression of cyclooxygenase-2 in ovarian mature cystic teratomas with malignant transformation

Cyclooxygenase-2 (COX-2) has been reported to be associated with tumor progression and angiogenesis and we previously reported that an increase in COX-2 expression might be associated with malignant transformation and tumorigenesis of epithelial ovarian neoplasms. In this study, COX-2 expression of ovarian mature cystic teratomas with malignant transformation, a rare entity accounting for just 1.8% of all mature cystic teratomas, was investigated using immunohistochemical techniques. There were 89 cases of mature cystic teratomas treated with surgery as their initial therapy at Osaka City University Medical School Hospital between 1995 and 2001. Ten cases of these were selected for study; five cases of mature cystic teratoma with malignant transformation, and five cases of mature benign teratoma. Expressions of CD34, vascular endothelial growth factor (VEGF), and COX-2 were investigated. Expressions of VEGF and COX-2 were strong in tissues of mature cystic teratomas with squamous cell carcinoma; however, expressions of them were hardly apparent in mature benign teratomas and in mature cystic teratomas with adenocarcinomas. These results tend to suggest that COX-2 is associated with tumor growth and progression in mature cystic teratomas with squamous cell carcinoma, as opposed to mature benign teratomas and mature cystic teratomas with adenocarcinomas.