Predictive and Prognostic Impact of Epidermal Growth Factor Receptor Mutation in Non–Small-Cell Lung Cancer Patients Treated With Gefitinib

TLDR: P-Akt overexpression was associated with prolonged TTP in patients with EGFR mutation, which further support the importance of EGFR mutations with regard to gefitinib sensitivity.

Abstract: Purpose This study was undertaken to investigate the effects of epidermal growth factor receptor (EGFR) mutation and its downstream signaling on response and survival in non–small-cell lung cancer (NSCLC) patients treated with gefitinib. Patients and Methods For 90 consecutive NSCLC patients who had received gefitinib, EGFR mutation was analyzed by DNA sequencing of exons 18, 19, 21, and 23 in the EGFR tyrosine kinase domain. Expressions of phosphorylated (p) -Akt and p-Erk were determined via immunohistochemistry. Response rate, time to progression (TTP), and overall survival were compared between each group according to EGFR mutation, as well as p-Akt and p-Erk expression. Results Seventeen patients (18.9%; 95% CI, 10.8 to 27.0) harbored EGFR mutations. These mutations include deletions in exon 19 in seven patients, L858R in six patients, G719A in three patients, and a novel A859T in one patient. Response rate in patients with EGFR mutation was 64.7% (11 of 17 patients; 95% CI, 42.0 to 87.4), in contras...