Our results implicate the importance of a large prospective investigation of the expression level and predictive value of not only the therapeutic target (i.e., EGFR protein) but also HER2 and other HER family members as therapeutic targets, or for response to therapy with anti-EGFR mAbs and other forms of HER inhibitors, in both the primary tumours and metastatic sites in mCRC. Here, EGFR is linked to neoplasm.