Background
Colorectal cancer (CRC) is the third most common cancer worldwide, with metastatic disease accounting for 40 to 50% of newly diagnosed patients. EGFR monoclonal antibodies (Mab), cetuximab and panitumumab, are effective treatment for KRAS wild type CRC. Although mutations in KRAS predict resistance to EGFR Mab therapy, only 80% of CRC patients with KRAS wild type status respond to treatment. This study is a retrospective evaluation of genomic alterations in the EGFR pathway such as alterations in KRAS, BRAF, NRAS, PIK3CA, and PTEN that may predict lack of response to EGFR Mab in CRC patients.