title: Prognostic significance of thymidylate synthase, dihydropyrimidine dehydrogenase and thymidine phosphorylase protein expression in colorectal cancer patients treated with or without 5-fluorouracil-based chemotherapy.
abstract: BACKGROUND
  Low tumour expression levels of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and thymidine phosphorylase (TP) have been linked with improved outcome for colorectal cancer (CRC) patients treated with 5-fluorouracil (5-FU). It is unclear whether this occurs because such tumours have better prognosis or they are more sensitive to 5-FU treatment.
  
  
  METHODS
  Associations between TS, DPD and TP levels, determined by tissue microarrays and immunohistochemistry, and survival was evaluated in 945 CRC patients according to treatment status.
  
  
  RESULTS
  Low TS and DPD expression associated with worse prognosis in stage II [hazard ratio (HR) = 1.69, 95% confidence interval (CI) (1.09-2.63) and HR = 1.92 (95% CI 1.23-2.94), respectively] and stage III CRC patients treated by surgery alone [HR = 1.39 (95% CI 0.92-2.13) and HR = 1.49 (95% CI 1.02-2.17), respectively]. Low TS, DPD and TP associated with trends for better outcome in stage III patients treated with 5-FU [HR = 0.81 (95% CI 0.49-1.33), HR = 0.70 (95% CI 0.42-1.15) and HR = 0.66 (95% CI 0.39-1.12), respectively].
  
  
  CONCLUSIONS
  Low TS and DPD expression are prognostic for worse outcome in CRC patients treated by surgery alone, whereas low TS, DPD and TP expression are prognostic for better outcome in patients treated with 5-FU chemotherapy. These results provide indirect evidence that low TS, DPD and TP protein expression are predictive of good response to 5-FU chemotherapy.
authors.affiliation: Oncology Research Institute, National University of Singapore, Singapore. nmirs@nus.edu.sg
authors.forename: R
authors.initials: R
authors.lastname: Soong
authors.forename: N
authors.initials: N
authors.lastname: Shah
authors.forename: M
authors.initials: M
authors.lastname: Salto-Tellez
authors.forename: B C
authors.initials: BC
authors.lastname: Tai
authors.forename: R A
authors.initials: RA
authors.lastname: Soo
authors.forename: H C
authors.initials: HC
authors.lastname: Han
authors.forename: S S
authors.initials: SS
authors.lastname: Ng
authors.forename: W L
authors.initials: WL
authors.lastname: Tan
authors.forename: N
authors.initials: N
authors.lastname: Zeps
authors.forename: D
authors.initials: D
authors.lastname: Joseph
authors.forename: R B
authors.initials: RB
authors.lastname: Diasio
authors.forename: B
authors.initials: B
authors.lastname: Iacopetta
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000201:enzymology* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D017024:Chemotherapy, Adjuvant; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000201:enzymology* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D042943:Dihydrouracil Dehydrogenase (NADP) / Q000032:analysis; D019008:Drug Resistance, Neoplasm; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005500:Follow-Up Studies; D006801:Humans; D002955:Leucovorin / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis*; D009367:Neoplasm Staging; D011379:Prognosis; D016019:Survival Analysis; D013939:Thymidine Phosphorylase / Q000032:analysis*; D013940:Thymidylate Synthase / Q000032:analysis*
chemical_list: D009363:Neoplasm Proteins; D042943:Dihydrouracil Dehydrogenase (NADP); D013940:Thymidylate Synthase; D013939:Thymidine Phosphorylase; D002955:Leucovorin; D005472:Fluorouracil