Recently, it was shown that adding panitumumab or cetuximab to oxaliplatin- or irinotecan-based chemotherapy produced a clear survival benefit when used as a first-line therapy, with this approach recommended for patents with left-sided metastatic colorectal cancer and wild-type RAS. Therefore, the majority of patients with left-sided colorectal cancer will be treated with anti-EGFR therapy as the first-line therapy. Here, EGFR is linked to colorectal cancer.