ROS1

ROS1 rearrangements occur infrequently in lung ACA, however given the frequency of lung cancer in the population, ROS1-rearranged tumors represent a significant number of cancer patients. ROS1 gene rearrangements are reported in 1–2% of lung adenocarcinomas (ACA) and are associated with response to the multitargeted tyrosine kinase inhibitor, crizotinib. ROS IHC can be readily incorporated into the diagnostic surgical pathology workup of lung adenocarcinoma, with results confirmed by FISH as needed.