Detection of epidermal growth factor receptor gene mutations in cytology specimens from patients with non-small cell lung cancer utilising high-resolution melting amplicon analysis

Background: Activating epidermal growth factor receptor ( EGFR) mutations have been implicated in non-small cell lung cancer (NSCLC), and have also been clinically correlated with patient sensitivity to targeted EGFR inhibitors. Aim: To describe a technique for determining EGFR mutation status on archival fine needle aspirate (FNA) specimens from advanced NSCLC patients. Methods: Eleven archival FNA slides from patients with advanced NSCLC were examined for diagnostic material to identify tumour cell-enriched regions. EGFR mutation status was determined using a slide-scrape DNA extraction protocol of selected tumour cell regions on the smear slides, followed by real time PCR and high resolution melt analysis (HRMAA) of EGFR exons 18, 19, 20, and 21, followed by sequence analysis. Results: All DNA samples were successfully amplified by PCR. Three adenocarcinoma patient samples contained EGFR mutations in exon 19 (L747-P753insS). One of the three had an additional exon 19 mutation (A755D). Conclusions: Archival cytology slides from patients with NSCLC can be used to determine EGFR mutation status by PCR, HRMAA, and sequencing. The ability to use archival cytology slides greatly increases the potential material available for molecular analysis in diagnosis and selection of patients for targeted therapeutic agents.