COX-2 immunohistochemical expression in epithelial ovarian carcinoma and platin sensitivity

Purpose: The aim of the study was to assess whether COX-2 expression in epithelial ovarian carcinoma (EOC) tissue can distinguish between platin-sensitive and platin-resistant tumors. Methods: Clinical and histological data were obtained from medical records of EOC patients diagnosed between the years 1995 and 2005. Patients in complete clinical remission for > 6 months after discontinuation of first-line chemotherapy were considered to be platin-sensitive. Survival of ≤ 2 and > 5 years after diagnosis was considered as short- and long-term survival, respectively. Immunohistochemistry staining was performed on deparaffinized sections of tissue blocks obtained at first surgery. The intensity of staining and the percentage of stained cells was assessed by two pathologists blinded to clinical data and a scoring index was calculated. Results: Among 79 patients a positive stain (> 10% of cells stained) was observed in 61 (77.2%). No statistically significant association between distribution of platin sensitivity and immunohistochemical COX-2 staining parameters was observed, although the rate of long-term survival was significantly higher among platin-sensitive then among platin-resistant/ unresponsive patients. Conclusions: Immunohistochemically determined COX-2 expression in EOC is not associated with platin sensitivity and survival.