Biomarkers in Predicting Neurotoxicity in Patients With Colorectal Cancer Receiving Oxaliplatin

RATIONALE: Studying samples of blood in the laboratory from patients receiving oxaliplatin for cancer may help doctors learn more about changes that occur in DNA and identify biomarkers related to neurotoxicity. PURPOSE: This phase II trial is studying biomarkers in predicting neurotoxicity in patients with colorectal cancer receiving oxaliplatin.