EGFR and cancer: It is preferentially expressed in cancers with functional complexity in cell signaling cascades such as extracellular signal-regulated kinases (ERK), mitogen-activated protein kinases (MAPK), heat shock protein-90 (HSP90), epidermal growth factor receptor (EGFR), phosphoinositide 3-kinase (PI3K), signal transducer and activator of transcription (STAT), hypoxia-inducible factor-1 alpha (HIF-1α), vascular endothelial growth factor (VEGF), and others.