Cyclooxygenase-2 expression in malignant mesenchymal tumors and related uterine lesions

The aim of this study was to determine whether the expression of cyclooxygenase-2 (COX-2) in uterine sarcoma cells and carcinosarcoma cells is associated with cell type. Nineteen sections of tissues from uterine sarcomas, carcinosarcomas, and an adenosarcoma, and endometrial stromal sarcomas, were immunohistochemically analyzed for the cellular expression of COX-2. Positive immunostaining for COX-2 was observed in 88.9% (8/9) uterine carcinosarcomas, uterine adenosarcomas but was not observed in uterine sarcomas and the endometrial stromal sarcoma (0/10). But positive immunostaining for COX-2 was observed in some sarcomatoid cells in carcinosarcoma tissue. These findings suggest that some of the sarcoma cells in uterine carcinosarcomas resemble epithelial malignant cells in regard to the increase in COX-2 expression, and support the hypothesis that some uterine carcinosarcomas are combination tumors. This may serve as a basis for new chemoprevention and treatment strategies for uterine carcinosarcomas through the inhibition of COX-2 activity.