Epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) have been reported to be related to certain clinical characteristics (i.e., female, non-smokers with adenocarcinoma) and gefitinib responsiveness. This exploratory analysis was performed to determine the incidence of EGFR mutations in male smokers with squamous cell carcinoma, who were treated with EGFR tyrosine kinase inhibitor, gefitinib. Sixty-nine Korean NSCLC patients were treated with gefitinib in a prospective study. For a subset of 20 male patients with squamous cell carcinoma and a history of smoking, pretreatment tumor tissue samples were obtained and analyzed for EGFR mutations (exons 18 to 21). EGFR mutations were found in 3 (15%) patients, including in-frame deletions within exon 19 (n=2) and L858R missence mutation in exon 21 (n=1). These 3 patients with EGFR mutations responded to gefitinib, whereas only one of remaining 17 patients with wild-type EGFR achieved clinical response. Trend toward longer progression-free (5.8 vs. 2.4 months; P=0.07) was noted in patients with EGFR mutations compared to those with wild-type EGFR. Although male smokers with squamous cell carcinoma have not been considered ideal candidates for gefitinib treatment, significant incidence of EGFR mutations was observed. The molecular markers should be considered to predict clinical benefits from gefitinib.
Keywords: Lung Neoplasms; Mutation; Receptor, Epidermal Growth Factor.