Fig. 3.

Compared to wild-type EGFR, the del L747-S752 mutant has similar sensitivity to TKIs, whereas the L858R mutant is inhibited at ≈10-fold lower concentrations of drug. (A) Dose-dependent inhibition by gefitinib of del L747-S752 mutant EGFR as compared to wild type. Cells were treated with gefitinib at various concentrations for 1 h before lysis. Results with erlotinib and in the presence of EGF were similar (data not shown). (B) Dose-dependent inhibition by erlotinib of L858R mutant as compared to wild-type EGFR. Dilution points at 0.0001 micromolar are not shown. Results with gefitinib were similar (data not shown). V, vector alone.