EGFR and lung cancer: The discovery of various molecular, genetic and epigenetic alterations that underlie lung cancer and breast cancer has improved the understanding of their tumorigenesis and it has contributed to the development of specifically targeted therapies employing protein overexpression inhibitors and specific mutation inhibitors, such as epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) [3,4,5].