EGFR and carcinoma: It was initially defined as a bifunctional growth factor, capable of inhibiting the proliferation of certain carcinoma cell lines while able to induce that of normal cells such as fibroblasts and keratinocytes.[1] As we all know, AREG is a member of the EGF family, its function is mainly mediated through binding and activating EGFR, a widely expressed tyrosine kinase receptor with 4 types, named ErbB1, ErbB2, ErbB3, and ErbB4.