Assessment of ros1 gene rearrangement in non-small cell lung cancer: concordance between ros1 sp384 immunohistochemistry and ros1 fish assay in a single center in türkiye

ROS1 IHC exhibited staining in cases harboring ALK, EGFR, and KRAS mutations, including one case with concurrent EGFR and ROS1 alterations. The ROS1 SP384 clone demonstrated 71.43% sensitivity and 84.97% specificity, with a negative predictive value of 99.3%. ROS1 IHC is a valuable screening modality for molecular alterations. FISH validation is recommended, and discordant cases may require NGS or RT-PCR for rare mutations or unidentified fusion partners.