Identifying EGFR mutations from SCLC patient plasma by mutant-enriched liquidchip technology.

Abstract

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) such as erlotinib and gefitinib are targeted drugs for the kinase domain of EGFR. They are widely used for the treatment of non-small cell lung cancer (NSCLC). The EGFR exon 19 deletion mutation and the L858R mutation in exon 21 comprise approximately 90% of the somatic mutations in NSCLC patients that respond to EGFR TKI. Several recent studies have also reported that small cell lung cancer (SCLC) patients with EGFR mutations responded to gefitinib. Further study, however, has been limited due to the difficulty obtaining tumor specimens from SCLC patients. The aim of this study was to explore the EGFR mutation status in SCLC patients by plasma analysis. Plasma samples from SCLC patients were collected for mutant-enriched liquidchip (MEL) analysis to identify the EGFR mutations in exon 19 and 21. The exon 19 deletion mutation was detected in one out of 35 patients (a female non-smoker). No exon 21 mutations were found. A prevalence of EGFR mutations in SCLC is rare, and occurs most frequently in females and nonsmokers.