The frequency and impact of FGFR1 amplification on clinical outcomes in Korean patients with small cell lung cancer.

Abstract

Fibroblast growth factor receptor 1 (FGFR1) plays a critical role in many human cancers. We tried to identify the frequency of FGFR1 amplifications among Korean patients with small cell lung cancer (SCLC). Additionally, we examined the clinical significance of FGFR1 amplifications for overall survival (OS) and progression-free survival (PFS) among SCLC patients who received standard chemotherapies. Tumor tissues from 158 Korean patients diagnosed with SCLC from September 2009 to February 2013 were collected and analyzed using an FGFR1 FISH assay with a probe that hybridized to chromosome region 8p12-8p11.23 (Abbott Molecular, Abbott Park, IL). FGFR1 amplification was detected in three patients (1.9%) harboring extensive disease (ED). A multivariate analysis showed that among the patients with ED, FGFR1 amplification was associated with shorter disease-free survival to first-line chemotherapy with etoposide plus cisplatin or carboplatin (hazard ratio [HR]=7.1; 95% confidence interval [CI]=2.0-25.4; P=0.003). The median overall survival time of the patients with ED was 8.2 and 10.2 months among patients with and without FGFR1 amplification, respectively (P=0.37). Although FGFR1 amplification is rare in SCLC compared to non-small cell lung cancer or other malignancies with squamous histology, it is associated with poor survival following standard chemotherapy in SCLC. Further studies in large cohorts of patients with SCLC are needed to verify these results. Our results imply that FGFR1 may be a potential therapeutic target in SCLC and it could be confirmed in a clinical trial.