A High Thymidylate Synthase Expression is Related to Better Outcome for Advanced Gastric Cancer Patients Treated with 5-FU Chemotherapy after Curative Resection

ABSTRACT

BACKGROUND: The expressions of thymidylate synthase (TS), E2F-1, pRb, and p53 are correlated with DNA synthesis. The significance of their expressions is still controversial for predicting the outcome of 5-fluorouracil (5-FU) therapy in the patients with advanced gastric carcinoma. Furthermore, their prognostic value in the metastatic lesions of gastric carcinoma has not yet been confirmed. METHODS: To ascertain their prognostic value, we immunohistochemically analyzed the expressions of TS, E2F-1, pRb, and p53 in the primary tumors and the related metastatic lymph nodes, and we then compared the survival between the high and low expression group of each protein. Ninety four patients with advanced gastric carcinoma who were treated by complete resection and adjuvant 5-FU chemotherapy were analyzed. RESULTS: The TS expression in primary tumors was significantly correlated with that of E2F-1. The expression of these genes showed no significant difference between the primary tumors and the metastatic lymph nodes except for E2F-1, which was significantly higher in the lymph node metastasis than in the primary tumors. After complete resection and 5-FU-based adjuvant chemotherapy, patients with a high TS expression in the primary tumors showed a longer survival than those patients having primary tumors with a low TS expression (p=0.0392). CONCLUSION: A high TS expression in the primary tumors may be related to a better outcome for advanced gastric cancer patients who were treated with 5-FU chemotherapy after curative resection.