Concomitant Mutations in EGFR 19Del/L858R Mutation and Their Association with Response to EGFR-TKIs in NSCLC Patients.

Concomitant mutations were widespread in 19Del and L858R and were associated with poorer OR to EGFR-TKIs. However, 19Del and L858R had similar numbers and patterns of concomitant mutations, which might not explain the different sensitivity to EGFR-TKI.