title: Thymidine phosphorylase and dihydropyrimidine dehydrogenase levels in primary colorectal cancer show a relationship to clinical effects of 5'-deoxy-5-fluorouridine as adjuvant chemotherapy.
abstract: Thymidine phosphorylase (TP) converts 5'-deoxy-5-fluorouridine (5'-DFUR, doxifluridine), an intermediate metabolite of capecitabine, to 5-fluorouracil (5-FU). While dihydropyrimidine dehydrogenase (DPD) catalyzes 5-FU to inactive molecules. We investigated TP and DPD levels in tumor tissue to assess their clinical significance as indicators for selecting colorectal cancer patients for 5'-DFUR adjuvant chemotherapy. A total of 88 colorectal cancer patients were classified into Dukes' B and C groups and treated for 2 years with oral 5'-DFUR (800 mg/body/day). During the follow-up period, 20 of the 88 patients developed a recurrence. All the patients were examined retrospectively for primary tumor TP and DPD levels and clinical response to 5'-DFUR. Results showed that: a) median levels of TP and DPD in the primary tumor, measured by enzyme-linked immunosorbent assay (ELISA), were, respectively, 43.6 and 32.3 U/mg protein. Primary tumor TP levels of the 20 patients who had a recurrence were lower than those of the 68 patients with no recurrence (p=0.07); b) although there were no significant differences in clinicopathologic features between high and low median TP level groups, disease-free survival was better in the high TP than in the low TP group (89% vs. 64%, at year 4); and c) of patients classified into 4 groups such as high TP/DPD, high TP but low DPD, low TP but high DPD, and low TP/DPD, patients with high TP but low DPD had the best disease-free survival, whereas the low TP but high DPD group had the worst survival. These results suggest that TP and DPD levels in primary colorectal tumors may be a useful indicator for selecting patients likely to respond to 5'-DFUR adjuvant chemotherapy and probably capecitabine, a prodrug of 5'-DFUR.
authors.affiliation: Department of Surgery II, School of Medicine, Kanazawa University, Kanazawa, Ishikawa 920-8641, Japan. genichi@surg2.m.kanazawa-u.ac.jp
authors.forename: Genichi
authors.initials: G
authors.lastname: Nishimura
authors.forename: Itsurou
authors.initials: I
authors.lastname: Terada
authors.forename: Takashi
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Itasu
authors.initials: I
authors.lastname: Ninomiya
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Kitagawa
authors.forename: Sachio
authors.initials: S
authors.lastname: Fushida
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujimura
authors.forename: Masato
authors.initials: M
authors.lastname: Kayahara
authors.forename: Koichi
authors.initials: K
authors.lastname: Shimizu
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Ohta
authors.forename: Koichi
authors.initials: K
authors.lastname: Miwa
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D000069287:Capecitabine; D017024:Chemotherapy, Adjuvant; D015179:Colorectal Neoplasms / Q000201:enzymology* / Q000401:mortality; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D042943:Dihydrouracil Dehydrogenase (NADP); D018572:Disease-Free Survival; D004797:Enzyme-Linked Immunosorbent Assay; D005467:Floxuridine / Q000627:therapeutic use*; D005472:Fluorouracil / Q000031:analogs & derivatives; D006801:Humans; D010088:Oxidoreductases / Q000096:biosynthesis*; D012008:Recurrence; D013939:Thymidine Phosphorylase / Q000096:biosynthesis*; D013997:Time Factors
chemical_list: D000964:Antimetabolites, Antineoplastic; D005467:Floxuridine; D003841:Deoxycytidine; D000069287:Capecitabine; D010088:Oxidoreductases; D042943:Dihydrouracil Dehydrogenase (NADP); D013939:Thymidine Phosphorylase; D005472:Fluorouracil; C025034:doxifluridine