KRAS Mutation Testing in the Treatment of Metastatic Colorectal Cancer with Anti-EGFR Therapies

Survival of patients with metastatic CRC (mCRC) has improved steadily over the past several decades, due largely to the development of new combinations of standard chemotherapy, as well as to the introduction of new targeted therapies. Among the available targeted therapies are two monoclonal antibodies that target the epidermal growth factor receptor (EGFR)—cetuximab and panitumumab—which have demonstrated efficacy in the treatment of mCRC. These therapies are associated with a unique set of toxicities and costs, prompting the need for tools to select patients who are most likely to derive a benefit from them. Mutations in the KRAS oncogene have consistently been shown to predict non-response to cetuximab and panitumumab. The role of KRAS as a marker of efficacy of anti-EGFR therapies is reviewed.