Molecular Mechanisms of Resistance to Cetuximab and Panitumumab in Colorectal Cancer

Personalized cancer medicine based on the genetic milieu of individual colorectal tumors has long been postulated, but until recently this concept was not supported by clinical evidence. The advent of the epidermal growth factor receptor (EGFR) -targeted monoclonal antibodies cetuximab and panitumumab has paved the way to the individualized treatment of metastatic colorectal cancer (mCRC). Here we discuss the evidence that mCRCs respond differently to EGFR-targeted agents and that the tumor-specific response has a genetic basis. We outline how, from the initial observation that cetuximab or panitumumab as monotherapy is effective only in 10% to 20% of mCRCs, knowledge has being gained on the molecular…