EGFR and non-small cell lung carcinoma: In view of this and because osimertinib is currently the preferred first-line treatment in EGFR-TKI-sensitizing variant-positive (eg, Ex19del, p.Leu858Arg) advanced NSCLC [4, 13, 19], cases of primary variant concordance but p.Thr790Met variant discordance are of less clinical importance at diagnosis.