ABSTRACT
OBJECTIVE: To study the association of inducible nitric oxide synthase (iNOS) expression with clinicopathological factors and prognosis in epithelial ovarian cancer. METHODS: The study included 301 patients with primary epithelial ovarian cancer. iNOS expression was evaluated by immunohistochemistry using a mouse monoclonal antibody. RESULTS: iNOS positivity was observed as granular deposits in the cancer cell cytoplasm. The mean percentage of iNOS-positive cells was 50% in primary tumors (n=301), and 62% in metastatic lesions (n=43). iNOS expression correlated significantly with histological subtype of the tumor, as high (> 70%) iNOS expression was observed in mucinous tumors (p=0.009). Poorly differentiated tumors showed a tendency to low (< or = 70%) iNOS expression but without statistical significance. Low iNOS expression associated also significantly with large primary residual tumor (p=0.007) and tumor recurrence (p=0.04). The 10-year prognosis of the patients with high iNOS expression was better in disease-related survival (DRS) (p=0.009). However, in multivariate analysis only FIGO stage, primary residual tumor, and grade of the tumor were independent prognostic factors for DRS, but not the iNOS expression. CONCLUSIONS: A major proportion of human epithelial ovarian cancers expressed iNOS. The positive expression was an indicator of better disease-related survival. However, iNOS positivity could not overcome the importance of clinicopathological factors in prediction of prognosis.
