EGFR and colorectal carcinoma: Accumulating evidence has delineated a number of signaling pathways whose deregulation contributes to CRC pathogenesis, including epidermal growth factor receptor (EGFR)/mitogen-activated protein kinase (MAPK), Hedgehog, Notch, phosphoinositide 3-kinase/protein Kinase B (PI3K/AKT), transforming growth factor-β (TGF-β), and WNT/β-catenin [3,4].