Gene Expression Analysis of Patients With Metastatic Colorectal Cancer Receiving Oxaliplatin Based Chemotherapy Regimen

Inclusion Criteria: * All patients, \>18 years of age, with metastatic/recurrent colorectal cancer are eligible. * Patients must have a life expectancy of at least 12 weeks. * Patients must have a Zubrod performance status of 0-2. * Patients must sign an informed consent. * Patients should have adequate bone marrow function defined by an absolute peripheral granulocyte count of \> 1,500 or cells/mm3 and platelet count \> 100,000/mm3 and absence of a regular red blood cell transfusion requirement. * Patients should have adequate hepatic function with a total bilirubin \< 2 mg/dl and SGOT or SGPT \< two times the upper limit of normal, and adequate renal function as defined by a serum creatinine \< 1.5 x upper limit of normal. * The patient must agree to a biopsy of a sample of tumor for correlative studies. * The patient is an appropriate candidate for oxaliplatin/capecitabine based chemotherapy. * The patient must have measurable disease. Exclusion Criteria: * Patients with symptomatic brain metastases are excluded from this study. * Pregnant women or nursing mothers are not eligible for this trial. Patients of child bearing potential must use adequate contraception. * Patients may receive no other concurrent chemotherapy or radiation therapy during this trial. * Patients with severe medical problems such as uncontrolled diabetes mellitus or cardiovascular disease or active infections are not eligible for this trial. * Patients may not have received oxaliplatin previously. * Patients with a prior unanticipated severe reaction to fluoropyrimidine therapy, or known dihydropyrimidine dehydrogenase (DPD) deficiency, or known hypersensitivity to platinum compounds or any of the components of the study medications.