Studying Tissue Samples From Patients With Stage II Colon Cancer Treated on Clinical Trial CLB-9581

This research trial studies tissue samples from patients with stage II colon cancer treated on Cancer and Leukemia Group B (CALGB)-9581 or CALGB-90903. Studying samples of tissue from patients with cancer in the laboratory may help doctors learn more about changes that occur in deoxyribonucleic acid (DNA) and identify biomarkers related to cancer. It may also help doctors understand how patients respond to treatment.