European guidelines currently recommend ROS1 rearrangement testing in patients with advanced NSCLC who have previously tested negative for EGFR mutation and ALK rearrangement, including all stage IIIB/IV histological subtypes in non-smokers and the non-squamous cell carcinoma subtype in current or ex-smokers [33]. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.