Clinical implication and usefulness of de novo EGFR T790M mutation in lung adenocarcinoma with EGFR-tyrosine kinase inhibitor sensitizing mutation.

The presence of de novo T790 M has limitation in predicting disease progression by acquired T790 M, suggesting that identifying de novo T790 M through the ultrasensitive methods may not be necessary identifying patients who would be beneficial by 3rd-generation EGFR-TKI as the 1st line treatment.