EGFR and cancer: At present, there are four classes of anti-EGFR agents used for cancer therapy: (i) monoclonal antibodies (MAbs) that is directed against the extracellular domain of EGFR [9,10], (ii) antisense oligonucleotides that inhibit EGFR synthesis [11], (iii) antibody-based immunoconjugates [12,13] and (iv) small molecules that block the kinase activity [also known as tyrosine kinase inhibitors (TKIs)].