Genotyping of EGFR Mutations from Bronchial Cytological Specimens in Slovakian Lung Cancer Patients

Non-small cell lung cancer (NSCLC) is a histologically and molecularly heterogeneous disease predominating in Slovakia among newly diagnosed oncological disorders and leading in the number of associated deaths. NSCLC diagnostics has advanced especially in molecular typing of epidermal growth factor receptor (EGFR) and subsequent targeted molecular therapy using tyrosine-kinase inhibitor(s) (TKI). The selection of patients for targeted therapy, we describe in this study, is mostly guided through bronchial smears rather than more invasive biopsies. We identified 32 adenocarcinomas, 40 squamous-cell carcinomas, 12 large-cell carcinomas, along with two unspecified carcinomas, in the NSCLC group who had bronchial smears taken. The assessment of tumor cell number, and genomic DNA allowed for screening of clinically relevant somatic EGFR mutations in 86 patients. Using quantitative PCR, 12 patients (14 %) were recommended for EGFR-TKI therapy. The most prevalent EGFR HIT-a in the somatosome, terms introduced and defined in this study, were exon 19 deletions, which were found in combination with the TKI-resistant p.T790M mutation in exon 20 in one patient. The study describes a method that is minimally invasive, reliable, and meets all criteria of routine molecular diagnostics. A multidisciplinary approach of EGFR genotyping from bronchial smears implemented in the study allows expanding targeted molecular therapy in NSCLC patients.