Our results show that activating EGFR mutations were predominantly detected in lung cancer, particularly in NSCLC, and co-occurred with the mutations of the genes participating in most key signaling pathways and biological processes, including receptors of different classes, key regulators involved in genome and epigenome stability, PI3K–AKT–mTOR pathway, and TP53/apoptosis pathway. This evidence concerns the gene EGFR and lung cancer.