Thymidylate synthase expression in epithelial ovarian cancer: Relationshipwith thymidine phosphorylase expression and prognosis

Objective: Thymidylate synthase (TS) and thymidine phosphorylase (TP) are i mportant enzymes involved in the de novo DNA synthesis and the salvage path ways for pyrimidine, respectively. Our purpose was to determine whether the gene expression of TS together with TP correlate with prognosis in epithel ial ovarian cancer. Methods: TS gene expression was analyzed by reverse tra nscription-polymerase chain reaction in 20 samples from normal ovaries and 56 epithelial ovarian cancers previously studied regarding TP gene expressi on. TS and TP protein localization was examined by immunohistochemistry. Re sults: TS gene expression was significantly higher in epithelial ovarian ca ncer than in normal ovaries (p = 0.001). In patients with epithelial ovaria n cancer, TS gene expression did not correlate with patient age, clinical s tage, histologic type, or histologic grade. High TS gene expression (> medi an) significantly correlated with a poorer survival (p = 0.02), No signific ant correlation between TS and TP gene expression and different immunoreact ivity patterns were found, Combined analysis of TS and TP gene expression d emonstrated that the relative risk of death for tumors with high TS and hig h TP expression was greater than that for either only high TS or high TP ge ne expression (p = 0.002). Conclusion: TS and TP combined may indicate a po or prognosis for patients with epithelial ovarian cancer. Copyright (C) 200 0 S. Karger AG, Basel.