Thymidylate synthase expression as a predictor of clinical response to 5-fluorouracil-based chemoradiotherapy in patients with maxillary sinus squamous cell carcinoma

Objective: The aim of this study was to evaluate the immunohistochemical TS expression in patients with maxillary sinus SCC. Methods The value of immunohistochemical TS expression as a predictive indicator for 5-FU efficacy was retrospectively examined in 47 patients with maxillary sinus SCC. Results Of the 47 patients, 29 (62%) showed complete response for 5-FU based chemoradiotherapy. Seventeen of 19 (89%) TS low cases showed a complete response, whereas 12 of 28 (43%) TS high cases showed complete response for 5-FU based chemoradiotherapy. Low TS patients had significantly better response rates compared with high TS patients. Conclusion These findings suggest that TS expression affects the chemotherapeutic effect of 5-FU in patients with maxillary sinus SCC and the assessment of TS expression level might be useful both in the management and in the treatment of maxillary sinus SCC.