ROS1 testing is not recommended in squamous cell carcinoma, except in the context of patients with no or low tobacco exposure [17, 22].Essentially, there are three methodological approaches to detecting ROS1 rearrangements: (a) IHC; (b) cytogenetic techniques, particularly FISH; and (c) molecular techniques, such as reverse transcription PCR (RT-PCR) or NGS [30, 38]. This evidence concerns the gene ROS1 and squamous cell carcinoma.