Proposed diagnostic algorithm using ROS1 and ALK IHC.

<p>When the tumor shows moderate to strong, or diffuse staining on IHC, FISH is recommend to confirm gene rearrangements. *The criteria should be determined based on each institutional method. According to this present study, subsequent FISH analysis is recommended for cases with an H-score ≥100, extent ≥75%, or the presence of intensity 2+ or 3+.