EGFR and metastatic colorectal cancer: Most patients will eventually relapse or become resistance to bivatuzumab, which is a humanized anti-CD44v6 variant monoclonal antibody to inhibit cell adhesion to hyaluronan [20,21]; besides, two anti-epidermal growth factor receptor (EGFR) mAbs, the chimeric IgG1 mAb cetuximab and the human IgG2 mAb panitumumab, have shown relevant clinical effect in chemotherapy-refractory metastatic colorectal cancer (mCRC) [22-25].