RATIONALE: Studying samples of tumor tissue in the laboratory from patients with cancer who have undergone surgery and chemotherapy may help doctors predict how well patients will respond to treatment.

PURPOSE: This research study is looking at tumor samples from patients with stage III colon cancer who have undergone surgery and chemotherapy.

OBJECTIVES:

• Identify predictive factors of efficacy and safety of adjuvant chemotherapy comprising fluorouracil-based regimens in patients with stage III colon cancer.
• Investigate possibility of "personalized treatment" with adjuvant chemotherapy based on the predictive factors identified.

OUTLINE: Patients' tumor tissue samples are collected for protein expression levels of thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD), VEGF, EGFR, mRNA-expression levels of TP, DPD, thymidylate synthase (TS), and orotate phosphoribosyl transferase (OPRT) by ELISA, Human Duo Set, and RT-PCR assays.

Patients' enzyme expression levels are compared with their clinical data.

<Inclusion criteria>

• Pathologically confirmed stage III colon adenocarcinoma
• Curatively resected (R0)
• Patients scheduled for treatment with fluorouracil-based post-operative adjuvant chemotherapy
• Provided written informed consent

<Exclusion criteria>

• Synchronous or metachronous multiple cancers
• Contraindications for fluorouracil-based chemotherapy
• Patients who have initiated neo-adjuvant chemotherapy or radiotherapy prior to participating in this study
• Ineligible patients according to the investigator's judgement

Pathologically confirmed stage III colon adenocarcinoma patients who are given treatment with fluorouracil-based post-opeartive adjuvant chemotherapy