Upregulation of thymidine phosphorylase in rectal cancer tissues by mitomycin C

J Surg Oncol. 2006 Jan 1;93(1):47-55. doi: 10.1002/jso.20390.


Background and objectives: We have investigated the regulation by mitomycin C (MMC) of thymidine phosphorylase (dThdPase) and dihydropyrimidine dehydrogenase (DPD), which enhances or reduces the efficacy of capecitabine and its metabolite 5'-deoxy-5-fluorouridine (5'-DFUR), in rectal cancer tissues.

Materials and methods: In 31 patients with a rectal cancer, tumor biopsies were performed before and after pre-operative venous administration of 4 mg/m2, 6 mg/m2, or 10 mg/m2 of MMC. The dThdPase and DPD levels in the biopsy and surgical specimens were measured using ELISA, and immunostaining for dThdPase was performed.

Results: The fitting multiple linear regression models indicated that the dThdPase levels increased after MMC administration, in particular in the patients with a pre-treatment dThdPase level less than 56.2 U/mg protein (median value). The time course analysis indicated that the increase in the dThdPase level by 4 mg/m2 of MMC administration continued for 3 weeks. The dThdPase/DPD ratio was increased after MMC administration in patients with a pre-treatment dThdPase/DPD ratio less than 1.79 (median value). MMC enhanced the expression of dThdPase protein both in the tumor cells and in the stromal cells. The disease free-survival rate in the Dukes B or C patients with a high dThdPase/DPD ratio in surgical specimen who received 5'-DFUR based adjuvant chemotherapy tended to be higher than that in those with a low dThdPase/DPD ratio.

Conclusion: MMC may upregulate the dThdPase level and the dThdPase/DPD ratio in rectal cancer tissues. Combined use of MMC with capecitabine or 5'-DFUR may offer a more effective colorectal cancer therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Analysis of Variance
  • Antineoplastic Combined Chemotherapy Protocols / pharmacology
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use
  • Capecitabine
  • Chemotherapy, Adjuvant
  • Deoxycytidine / administration & dosage
  • Deoxycytidine / analogs & derivatives
  • Deoxycytidine / pharmacology
  • Dihydrouracil Dehydrogenase (NADP) / genetics
  • Dihydrouracil Dehydrogenase (NADP) / metabolism
  • Disease-Free Survival
  • Female
  • Floxuridine / administration & dosage
  • Floxuridine / pharmacology
  • Fluorouracil / analogs & derivatives
  • Humans
  • Immunohistochemistry
  • Male
  • Middle Aged
  • Mitomycin / administration & dosage
  • Mitomycin / pharmacology*
  • Rectal Neoplasms / drug therapy
  • Rectal Neoplasms / enzymology
  • Rectal Neoplasms / genetics*
  • Rectal Neoplasms / surgery
  • Thymidine Phosphorylase / genetics*
  • Thymidine Phosphorylase / metabolism
  • Up-Regulation / drug effects*


  • Floxuridine
  • Deoxycytidine
  • Mitomycin
  • Capecitabine
  • Dihydrouracil Dehydrogenase (NADP)
  • Thymidine Phosphorylase
  • Fluorouracil
  • doxifluridine