Detection And Clinical Significance Of Epidermal Growth Factor Receptor Mutation In Transbronchial Needle Aspiration Of Non-Small Cell Lung Cancer

Objective:To study the feasibility of detecting epidermal growth factor receptor (EGFR) mutations through amplification refractory mutation system (ARMS) in patients with non-small cell lung cancer (NSCLC) on small specimens from transbronchial needle aspiration (TBNA), and to investigate its clinical significance.Methods:From February 2013 to January 2015, Thirty NSCLC patients were enrolled by conventional transbronchial needle aspiration (C-TBNA) biopsy and (or) by transbronchial ultrasound-guided needle aspiration (EBUS-TBNA) to obtain embedded cytological specimens and (or) small tissue specimens. All patients of cytological specimens were processed by special liquid-based solution, and then fixed in formalin; and formalin-fixed TBNA tumor samples fixed in formalin directly. Finally all samples were paraffin embedded into paraffin mass, according to histological methods. TBNA specimens with paraffin mass were micro-dissected to obtain sufficient tumor tissue, using QIAamp DNA extraction kit to extract genomic DNA. The samples were detected on EGFR mutations situation by ARMS in non-small cell lung cancer patients.Results:There were TBNA samples with EGFR gene mutations of 30 NSCLC patients detected by ARMS, the presence of EGFR mutations in 13 cases. The rates of mutation detection were achieved to 43.3%(13/30), which distribution in exon 19 in 7 cases, and in exon 21 in 5 patients. One case of TBNA embedded cytological specimens had mutation at exon 19 in concomitance with 21, and its TBNA small tissue samples in exon 21 point mutations only. There were higher the rates of mutations detected in females than that in males, there was significant statistical difference (P<0.05). Non-smoking group EGFR mutation rate was higher than that in the smoking group. Between EGFR gene mutation status and sex, smoking history and histology were no significant statistical difference (P>0.05). Five NSCLC patients with embedded cytological specimens at the same time get TBNA small histological specimens to detect EGFR gene mutations, the results of two cases TBNA embedded cytological specimens detected mutations, three cases were wild type. Similarly, TBNA small tissue samples detected two cases of mutations, three cases of the wild type. A part of TBNA specimens and its tumors tissues EGFR mutation detection rate was 83.3% in line with the overall result. There was EGFR mutation detected in one patient on TBNA small tissue specimens, while its EGFR situation on histological specimens was wild type.Conclusions:1. TBNA cytology specimens after special treatment can become qualified to detect EGFR specimens.2. It is feasible to value the EGFR mutation status in TBNA small samples (embedded cytology specimens and small tissue specimens) of NSCLC patients detected by ARMS assay.3. EGFR gene mutation situation of TBNA embedded cytological specimens is consistent with that offered by the TBNA histological samples obtained from the same patient.