In the research previously published, the presence of EGFR mutations, such as deletions in exon 19 and L858R mutation, led to a higher sensitivity to tyrosine kinase inhibitors in patients with non-small-cell lung cancer, including lung adenocarcinoma [41,42,43], while the T790M mutations of EGFR before treatment is related to a significantly shorter progression-free survival [41]. The gene discussed is EGFR; the disease is lung adenocarcinoma.