Fig 1.

(A) A break-apart fluorescent in situ hybridization probe reveals separation of the 5′ ROS1 probe (green) from the 3′ ROS1 probe (red) in a non–small-cell lung cancer formalin-fixed paraffin-embedded specimen. Nuclei are stained with 4′,6-diamidino-2-phenylindole. Size bar = 10 μm. (B) Representative histologic appearance of a ROS1-rearranged tumor, stained with hematoxylin and eosin, showing a solid subtype of adenocarcinoma with highly atypical cytologic features. (C) Sanger sequencing of a reverse transcriptase polymerase chain reaction product from a tumor harboring a SLC34A2-ROS1 rearrangement.