Coexpression of cyclooxygenase-2 and thymidine phosphorylase as a prognostic indicator in patients with FIGO stage IIB squamous cell carcinoma of uterine cervix treated with radiotherapy and concurrent chemotherapy

Abstract

To evaluate the prognostic significance of thymidine phosphorylase (TP) and coexpression of cyclooxygenase-2 (COX-2)/TP, and to investigate the relationship between COX-2 and TP expression in squamous cell carcinoma of the uterine cervix. Cancer specimens from 75 patients with International Federation of Gynecology and Obstetrics Stage IIB squamous cell carcinoma of the uterine cervix who had undergone radiotherapy and concurrent chemotherapy were immunohistochemically stained with COX-2 and TP antibodies and scored. The prognostic significance of their expression status, and the relationship between COX-2 and TP was investigated. TP predominantly stained cytoplasm and the cell membrane of the tumor cells mainly in a diffuse and intense manner. TP was negative (<10% distribution) in 17%, 1+ (10-50%) in 25%, and 2+ (>50%) in 57% of patients. TP overexpression was related to a marginal prognostic significance of a poor 5-year overall survival (p = 0.082, log-rank test) and a high locoregional recurrence rate (p < 0.1, chi-square test). COX-2 and TP coexpression was observed in 24% of patients and was significantly related to poor 5-year disease-free and overall survival rates (p = 0.0083 and p = 0.025, respectively), a high pelvic lymph node involvement rate, a poor response to treatment, and a greater incidence of locoregional recurrence (p < 0.05). By multivariate analyses, only COX-2, TP, and coexpression of COX-2/TP were significant independent prognostic indicators of patient survival. All tumors showed 1+ or 2+ TP expression when COX-2 was positive, and no tumor expressed COX-2 when TP was negative (p = 0.03). In contrast, 77% of tumors expressed 1+ or 2+ TP without the synchronous expression of COX-2. Thymidine phosphorylase expression or COX-2/TP coexpression may be used as a molecular prognostic marker for squamous cell carcinoma of the uterine cervix. TP appears to be an important downstream molecule of COX-2 during angiogenesis and may be a new target for the treatment of uterine cervical cancer.