Clinicopathological significance of deoxycytidine kinase expression in esophageal squamous cell carcinoma

Deoxycytidine kinase (dCK) mediates the rate-limiting catabolic step in the activation of gemcitabine. Gemcitabine is a key drug for pancreatic and biliary tract cancer. However, gemcitabine is not widely used for esophageal squamous cell carcinoma (ESCC). In this study, we analyzed the expression of dCK in ESCC and evaluated the possibility of gemcitabine treatment for ESCC. In total, 76 ESCC patients who underwent esophagectomy between 1990 and 2008 were analyzed. dCK expression was analyzed immunohistochemically using tissue microarray and compared to the clinocopathological characteristics of the patients. Results identified 41 patients positive for dCK and 35 patients negative for dCK. A significant association was observed between dCK expression and gender (P=0.01), whereas the remaining factors were not associated with dCK expression. Prognosis of the patients with a high dCK expression was significantly worse than that of the patients with a low dCK expression (P=0.022). Furthermore, dCK expression was an independent prognostic factor regarding cause-specific prognosis (risk ratio, 2.2; P=0.031). In conclustion, the results of the present study suggested that dCK expression is a prognostic factor of the ESCC patients.