This pilot study is being mounted to assess whether treatment assignment by ERCC-1 gene expression status suggests better clinical results from historical experience in metastatic colorectal cancer (mCRC). In wild type KRAS mCRC patients treated with either FOLFOX or FOLFIRI in combination with cetuximab the median response rate is approximately 60-65%. Biomarker directed treatment in this study may demonstrate that patients with low ERCC-1 treated with FOLFOX and cetuximab, and those with high ERCC-1 treated with FOLFIRI and cetuximab, will improve response rate to 70-75%. KRAS wild type patients will be treated with 6 cycles of one of the following regimens chosen for optimization based on patient characteristics (primary treatment phase). Patients with ERCC-1 < 1.7 relative gene expression of ERCC-1 over ß-actin (ERCC-1 low) will be assigned to treatment with mFOLFOX6 in combination with Cetuximab. Patients with ERCC-1 gene expression > 1.7 relative gene expression of ERCC-1 over over ß-actin (ERCC-1 high) will be assigned to treatment with FOLFIRI in combination with Cetuximab.