This study is a parallel translational study of a Randomized Phase III trial 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 (MIDAS trial: protocol NCCCTS-467) . Patients participating in the trial will be provided with the informed consent of this parallel study, and peripheral blood and tumor tissue of those who signed the consent will be collected for germline polymorphism analysis and gene expression profile study .

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

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