Resistance to EGFR targeted antibodies - expansion of clones present from the start of treatment. The more things change, the more they stay the same (Plus ca change, plus ca ne change pas!)

The management of metastatic colorectal cancer (mCRC) has evolved with the development of targeted therapies. Two monoclonal antibodies, panitumumab and cetuximab, directed against the epidermal growth factor receptor (EGFR), have efficacy either in combination with chemotherapy or alone in the chemotherapy-refractory setting (1-3).