Robust Performance of the Novel Research-Use-Only Idylla GeneFusion Assay Using a Diverse Set of Pathological Samples with a Proposed 1-Day Workflow for Advanced NSCLC Evaluation

: A range of different techniques are available for predictive biomarker testing for non-small-cell lung cancer (NSCLC) clinical management. International guidelines suggest next-generation sequencing (NGS) as the preferred procedure, but other reverse transcriptase-polymerase chain reaction (RT-PCR)-based methods are rapidly evolving. In this study, we evaluated the reliability and accuracy of the IdyllaTM GeneFusion assay, a rapid and fully automated platform able to simultaneously detect ALK, ROS1, RET and NTRK1/2/3 and MET ex14 skipping mutations and compared its performance with routine reference methods. The cohort included thirty-seven NSCLCs plus two parotid gland carcinomas, previously characterized for the above alterations through either IHC, FISH, RT-PCR or NGS. In 36 of 39 cases, the Idylla GeneFusion assay and the reference methods were concordant (overall agreement: 92.3%). Tumor sections stored at room temperature for up to 60 days and 17 cases older than 2 years were successfully characterized. Our results suggest that the Idylla GeneFusion assay is a reliable tool to define gene fusion status and may be a valuable stand-alone diagnostic test when time efficiency is needed or NGS is not feasible.