EGFR and non-small cell lung carcinoma: This study investigated the frequency of EGFR mutation and its association with PD-L1, ALK, and ROS1 expression in patients with NSCLC from Northwest Iran.<h4>Material and methods</h4>A retrospective analysis was conducted on 647 cases of NSCLC from April 2018 to August 2024 at Imam Reza Hospital in Tabriz, Iran.