Figure 1.

Image of FISH assay detecting ROS1 rearrangements (indicated by arrows) and image of NGS RNA panel (Oncomine Dx) detecting EZR–ROS1 fusion. Both tests were performed at our Molecular Pathology Laboratory on cytoblock specimen from pleural effusion in a 55-year-old woman (non-smoker) diagnosed with advanced adenocarcinoma of the lung. In this particular case, IHC screening was positive, but FISH assay was positive for rearrangement only on 8% of cells, not meeting the positivity threshold (≥15%), but fusion was then confirmed by NGS testing. Patient gave her informed consent to publish images and her clinical information.