To test the possibility that D6 preferentially inhibits L858/T790M-EGFR addicted NSCLC cells, we generated an isogenic cell line from HCC827 by stably expressing L858R/T790M-EGFR and then selected by erlotinib, to mimic the erlotinib resistance. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.