A Prospective Study of Pharmacogenetic Factors and Gene Expression Profile

Inclusion Criteria: * Curatively resected, histologically confirmed colon adenocarcinoma (presence of the inferior pole of the tumor above the peritoneal reflection) * AJCC/UICC high-risk stage II, stage III colon cancer Stage II patient with high risk of relapse, if they fulfill one or more of the following criteria:(T4 tumors,bowel obstruction or perforation,vascular or lymphatic or perineural invasion) * Patients who are participating in the randomized phase II trial of FOLFOX 6 or 12 cycles * Patients should sign a written informed consent for this translational study before or during participating in a randomized phase III study investigating the role of oxaliplatin duration (6 cycles versus 12 cycles) in modified FOLFOX-6 regimen as adjuvant therapy for patients with stage II/III colon cancer Exclusion Criteria: * Patients who do not agree with sampling of peripheral blood for genetic analysis * Patients who are considered not to be suitable for this study at investigator's discretion