In Response

Abstract

We thank Uguen et al. for their interest in our recently published manuscript titled Comparison of methods in the detection of ALK and ROS1 rearrangements in lung cancer.1Rogers TM Russell PA Wright G et al.Comparison of methods in the detection of ALK and ROS1 rearrangements in lung cancer.J Thorac Oncol. 2015; 10: 611-618Abstract Full Text Full Text PDF PubMed Scopus (67) Google Scholar We acknowledge their concerns regarding the use of homemade fluorescent in situ hybridization (FISH) probes and the importance of their design. At the time that the study was conducted there were no commercial ROS1 FISH probes available therefore we used the home-made ROS1 FISH probe that was kindly gifted to us from Translational Research Laboratory, Massachusetts General Hospital and previously utilized in the study by Bergethon et al.2Bergethon K Shaw AT Ou SH et al.ROS1 rearrangements define a unique molecular class of lung cancers.J Clin Oncol. 2012; 30: 863-870Crossref PubMed Scopus (1272) Google Scholar Subsequently, when commercial ROS1 FISH probes became available, specifically the Cytocell Aquarius ROS1 Breakapart FISH Probe (Cambridge, UK) and Vysis 6q22 ROS1 Break Apart FISH Probe Kit (Des Plaines, IL), we repeated the cases which were considered ROS1 positive or atypical. The Cytocell Aquarius ROS1 Breakapart FISH Probe showed the same results as with the homemade ROS1 FISH probe. However, the Vysis 6q22 ROS1 Break Apart FISH Probe Kit showed the same results for the positive case which contained the break and the atypical case (loss of 3′ end) but the two other cases defined by loss of the 5′ end using the home-made ROS1 FISH probe were negative by the Vysis 6q22 ROS1 Break Apart FISH Probe Kit. This as anticipated and highlighted by Uguen et al. show there are differences in FISH signal patterns that is dependent on probe design. Searching for ROS1 Rearrangements in Lung Cancer by Fluorescent In Situ Hybridization: The Importance of Probe DesignJournal of Thoracic OncologyVol. 10Issue 8PreviewWe read with much interest the study by Rogers et al. concerning the use of fluorescence in situ (FISH), chromogenic in situ hybridization, and immunohistochemistry (IHC) for the detection of ALK and ROS1 rearrangements in lung cancer.1 They concluded that FISH versus IHC showed good correlation in the detection of ALK rearrangements but weak correlation in the detection of ROS1 rearrangements. Full-Text PDF Open Archive