“…These results have led to a consensus that the presence of EGFR mutations is a strong predictor of TKI treatment response and various associations and working groups, internationally and in Poland, now recommend screening newly diagnosed patients with advanced NSCLC for specific mutations in order to customize the modality of treatment (9,(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32). Despite these, the incidence rates of EGFR mutations are found to vary substantially between different regions and countries (8,10,15). Possible reasons for this discrepancy could be lack of clarity in selection criteria for EGFR-positivity testing, differences in molecular methods employed for screening, and issues with sampling and tissue preservation.…”