title: Changes in intratumoral thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) mRNA expression in colorectal and gastric cancer during continuous tegafur infusion.
abstract: Thymidylate synthase (TS) is the target enzyme of 5-fluorouracil (5-FU), and dihydropyrimidine dehydrogenase (DPD) is the key enzyme in the 5-FU catabolic pathway. We wanted to determine whether the TS and DPD mRNA expression levels of gastric and colorectal cancer patients would be affected by tegafur (futrafur:FT)-based chemotherapy and whether changes in their expression might be responsible for patient outcome. Thirty-five patients with resectable advanced primary gastric cancer and 36 patients with resectable advanced primary colorectal cancer were the subjects of this study. They all underwent neoadjuvant chemotherapy with protracted infusion of FT alone or FT plus low doses of cisplatin. The TS and DPD mRNA expression levels of endoscopic biopsy specimens before chemotherapy and surgical specimens after chemotherapy were measured by TaqMan reverse transcription-PCR assay using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as the internal standard. There was a significant difference in the DPD mRNA levels during chemotherapy in the colorectal cancers. Although the TS and DPD levels were unrelated to any conventional histopathological grade factors, colorectal cancer patients whose surgical specimens contained lower TS and DPD mRNA levels had longer disease-free intervals. The results of this study suggest that FT may affect DPD mRNA expression in colorectal cancer patients, that TS/DPD expression can be regarded as an independent prognostic factor, and that colorectal cancer patients with low TS and low DPD mRNA are candidates for FT-based adjuvant chemotherapy. In addition, quantitative analysis of the change in TS/DPD mRNA in surgical specimens during FT-based chemotherapy might be a more accurate means of predicting the post-operative disease-free interval of colorectal cancer patients than analysis of endoscopic specimens before chemotherapy. There also seems to be a relation between regulation of TS and DPD during FT chemotherapy. Elucidation of the mechanisms regulating TS and DPD mRNA expression might make it possible to predict sensitivity and/or toxicity to FT.
authors.affiliation: Department of Surgery, Institute of Gastroenterology, Tokyo Women's Medical University, 8-1 Kawadachou, Shinjuku-ku, Tokyo 162-8666, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Uchida
authors.forename: K
authors.initials: K
authors.lastname: Hayashi
authors.forename: H
authors.initials: H
authors.lastname: Kuramochi
authors.forename: K
authors.initials: K
authors.lastname: Takasaki
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002945:Cisplatin / Q000008:administration & dosage / Q000627:therapeutic use; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D042943:Dihydrouracil Dehydrogenase (NADP); D018572:Disease-Free Survival; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D010088:Oxidoreductases / Q000235:genetics*; D012333:RNA, Messenger / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D005641:Tegafur / Q000008:administration & dosage / Q000627:therapeutic use*; D013940:Thymidylate Synthase / Q000235:genetics*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D012333:RNA, Messenger; D005641:Tegafur; D010088:Oxidoreductases; D042943:Dihydrouracil Dehydrogenase (NADP); D013940:Thymidylate Synthase; D002945:Cisplatin