Consequently, cetuximab, an IgG1-subclass anti-EGFR monoclonal antibody that blocks the activation of tyrosine kinase –dependent molecular signaling pathway by binding to extracellular domain of epidermal growth factor receptor (EGFR) was approved by FDA for the treatment of locoregionally-advanced (LA), as well as recurrent/metastatic disease [93]. Here, EGFR is linked to metastatic neoplasm.