Correlations of Clinicopathological Factors with Protein Expression Levels of Thymidylate Synthase, Dihydropyrimidine Dehydrogenase and Orotate Phosphoribosyltransferase in Colorectal Cancer

Abstract

Background: Expression levels of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and orotate phosphoribosyltransferase (OPRT) have been reported to be associated with tumor response to 5-fluorouracil (5-FU). Method: We investigated correlations of clinicopathological factors with protein expression levels of TS, DPD, OPRT in colorectal cancer (CRC). The subjects were 202 patients who had undergone CRC resection. Result: There was a negative correlation between DPD and OPRT protein levels, but no correlation of TS levels with either OPRT or DPD levels. The DPD levels in women was significantly lower than that in men. The DPD level was significantly lower in colonic tumors than in rectal tumors, while the OPRT level was significantly higher in colonic tumors than in rectal tumors. The TS level did not correlate with any clinicopathological factors. Conclusion: DPD and OPRT protein levels in CRC suggest that female gender and colonic tumors are positive prognostic factors in patients who receive chemotherapy with 5-FU.