The former is the case of the S492R mutant, which confers resistance to cetuximab since the mutation is located in its binding epitope on the EGFR external domain (Montagut et al., 2012); whereas the later is the case of the T790M mutant (mutation in the kinase domain), which confers resistance to gefitinib or erlotinib in lung adenocarcinomas (Pao et al., 2005) by stabilizing the active tyrosine kinase conformation and enhancing aTP binding (Yoshikawa et al., 2013). The gene discussed is EGFR; the disease is lung adenocarcinoma.