Thymidine phosphorylase affects clinical outcome following surgery and mRNA expression levels of four key enzymes for 5-fluorouracil metabolism in patients with stage I and II non-small cell lung cancer.

The expression levels of thymidine phosphorylase (), dihydropyrimidine dehydrogenase (), thymidylate synthase () and orotate phosphoribosyltransferase () may predict the clinical efficacy of 5-fluorouracil-based chemotherapy in patients with cancer. We herein investigated the differences in the mRNA levels of these enzymes in non-small-cell lung cancer (NSCLC) and evaluated their prognostic value for NSCLC treated by surgical resection. The intratumoral mRNA levels of , and were quantified in 66 patients with pathological stage I and II NSCLC (adenocarcinoma or squamous cell carcinoma) following complete resection according to the Danenberg Tumor Profile method. The level was the only significant prognostic factor for disease-specific survival (DSS) following complete resection; the mean mRNA level differed significantly between the high and low mRNA expression groups. The DSS at 5 years was significantly higher in the low mRNA compared with that in the high mRNA expression group (83.4 vs. 58.6%, respectively; P=0.005). A Cox proportional hazards model revealed that pathological stage, sex, and expression were independent prognostic factors for DSS in patients with stage I and II NSCLC following complete resection. Thus, level may be used to monitor treatment efficacy and predict the outcome of NSCLC patients.