The mutation(s)/alteration(s) in specific genes, such as EGFR (epidermal growth factor receptor) or ALK (anaplastic lymphoma kinase) (among others), in NSCLC are considered predictive biomarkers since they can be used as targets for specific tyrosine kinase inhibitor (TKI) therapy, being also indicative of sensitivity or resistance to specific TKI treatments [5,6]. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.