PC9 cells (Gef-sensitive EGFR mutant LAC cells) and A549 cells (Gef-resistant EGFR wild-type LAC cells) were exposed to Gefitinib (Gef, Iressa, the most commonly used TKI in lung adenocarcinoma) and/or Tamoxifen (TAM, the most commonly used SERM). The gene discussed is EGFR; the disease is lung adenocarcinoma.