In accordance with these data, our results demonstrated loss of PTEN protein and overactivation of Akt in NSCLC subpopulations with highly metastatic potential and natural resistance to gefitinib, and indicated that PTEN protein level and Akt phosphorylation state may be additional key predictors of de novo resistance to gefitinib. Here, AKT1 is linked to non-small cell lung carcinoma.