EGFR and colorectal carcinoma: Similarly, extracellular domain mutations in EGFR, which occur in about 20% of CRC patients treated with anti-EGFR mAbs33, can be treated with oligoclonal antibodies like MM-151 and Sym004, which have been shown to overcome this resistance mechanism in model systems and are now being explored clinically as secondary therapies for patients who have relapsed on anti-EGFR mAbs33,37,38.