EGFR and cancer: The phosphatidylinositol 3-kinase (PI3K)-AKT and MAPK kinase (MEK)–extracellular-related kinase (ERK) pathways play a central role in transmitting the oncogenic signals downstream of ErbB RTKs thus contributing to cancer phenotype in terms of cell cycle progression, survival, metastasis, reprogramming of metabolism and resistance to chemotherapy.