L858R-positive lung adenocarcinoma with KRAS G12V, EGFR T790M and EGFR L858R mutations: A case report.

Improvement in the current understanding of the molecular basis of lung cancer at multiple levels, including the genetic, epigenetic and protein levels, has the potential to impact the diagnosis, prognosis and treatment of lung cancer. The mutation status of the tyrosine kinase domain of epidermal growth factor receptor (EGFR) is known to be a predictor of the response to gefitinib in lung cancer. Furthermore, mutations in the EGFR and KRAS genes appear to be mutually exclusive. The present study reports a rare case of a patient harboring two EGFR mutations (L858R and T790M) and a KRAS mutation (G12V). The development of gefitinib resistance was detected in the subsequent treatment. The present study indicates that EGFR and KRAS mutational analysis should be recommended for all patients with non-small-cell lung carcinoma.