Cyclooxygenase-2 expression in human soft-tissue sarcomas is related to epithelial differentation.

BACKGROUND Cyclooxygenase-2 (Cox-2) is expressed by several types of epithelial malignancies, i.e., carcinomas, and inhibition of Cox-2 may have a therapeutic role in chemoprevention and treatment of cancer. The role of Cox-2 in non-epithelial malignancies, however, is unclear. MATERIALS AND METHODS We investigated, by immuno- histochemistry, the expression of Cox-2 in 103 human soft-tissue sarcomas. RESULTS All 10 biphasic synovial sarcomas were positive for Cox-2, but positivity was observable only in the epithelial component of these tumours. Excluding sarcomas with epithelial differentation, uniform staining of the tumour was observed in only 2 samples. In addition, positivity for Cox-2 appeared in tumour cells in only 18 samples around necrotic areas. CONCLUSION In human soft-tissue sarcomas, Cox-2 expression seems to be associated with epithelial differentation and, in some types of sarcomas, to be expressed in otherwise negative tumours at sites of necrosis.