EGFR and cancer: The epidermal growth factor receptor tyrosine kinase (EGFR-RTK) is a ligand-dependent RTK that is overexpressed and/or constitutively activate in a wide variety of cancer cell types including NSCL, breast, melanoma, colorectal, pancreatic, glioblastoma, esophageal, and head and neck cancers.24 The receptor is encoded by the EGFR proto-oncogene located on Chromosome 7, which is subject to oncogenic gene amplification as well as activating point mutations.