EGFR and head and neck cancer: Constitutive hyperactivation of EGFR-signaling pathways as a result of gene amplification, gain-of-function point mutations, or increased expression is present in a number of malignancies of epithelial origin, including breast and ovarian carcinomas (Her2/neu proto-oncogene), lung cancer (ErbB1, ErbB3), head and neck cancer, colorectal cancer, glioblastomas, etc. [174,175,176,177,178,179].