Brief Report: Clinical Utility Validation of an Automated Ultra-Rapid Gene Fusion Assay for Non-Small Cell Lung Cancer

Open AccessPublished:November 08, 2022DOI:
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      Gene rearrangements are frequent oncological drivers in non-small cell lung cancer (NSCLC), and many are suitable for treatment with FDA-approved or experimental targeted therapies. We evaluated the accuracy, specimen acceptance profile, and limits of detection of a rapid fusion assay (IdyllaTM GeneFusion Assay), a commercially available ultra-rapid molecular assay, for its clinical utility.


      A collection of 97 specimens which had previously undergone NGS testing were analyzed using the rapid fusion assay. Accuracy was evaluated by sensitivity and specificity compared to the NGS results. The performance characteristics were tested by using a variety of different clinically relevant specimen types. Limits of detection were assessed by examining different input of tumor percentage and material amount.


      The rapid fusion assay demonstrated 100% sensitivity in detecting fusions of ALK, ROS1, RET, NTRK1, and MET exon 14 skipping; and 83% sensitivity for NTRK2/3 fusions. There was 100% specificity in detecting fusions of ROS1, RET, NTRK2/3, and MET exon 14 skipping; and 98% specificity for ALK. Testing was successful with formalin-fixed paraffin-embedded biopsy and surgical tissues, cell blocks from fine needle aspiration and pleural fluid (down to 5% tumor content, 18 mm2 tissue scraped), cytology smears (≥300 cells) and previously extracted RNA (minimal 20 ng).


      The rapid fusion assay is quick, accurate and versatile, allowing reliable detection of ALK, ROS1, RET fusions, and MET exon 14 skipping in NSCLC, as well as NTRK fusions. Rapid molecular testing may expedite treatment with appropriate targeted therapies.