EGFR and lung adenocarcinoma: The presence of activating EGFR mutations, mainly in exons 18, 19, 20 and 21, which correspond to the tyrosine kinase domain, sensitizes lung adenocarcinomas to treatment with anti-EGFR tyrosine kinase inhibitors (TKi), such as erlotinib, gefitinib, afatinib, dacomitinib and osimertinib15,16.