EGFR and lung adenocarcinoma: Mutations of growth factor receptors or members of their respective signaling pathways are characteristics for many different cancer types: EGFR mutations in lung adenocarcinoma, HER2 amplifications in breast and gastric cancers, RAS mutations in lung and colorectal cancers, BRAF mutations in melanoma, thyroid or GI-tract cancers or mutations of the lipid kinase signaling pathway members (PI3KCA, AKT) in various cancer types [17].