Key Points
• Conclusion/Relevance: “Abbott Molecular break-apart FISH probes can be used to detect RET fusions. Laboratories can optimize cutoffs and/or testing algorithms to maximize sensitivity and specificity to ensure appropriate patients receive effective, timely therapy.”
• Selpercatinib (RETEVMO) is a targeted inhibitor of RET, which was recently FDA approved for the treatment of RET fusion–positive nonsmall cell lung cancer and nonmedullary thyroid cancer, thus highlighting the necessity for rapid and accurate diagnosis of RET fusions. Although understudied with respect to RET, fluorescence in situ hybridization (FISH) has been leveraged to detect gene rearrangements.
• The Abbott Molecular break-apart FISH assay demonstrated high sensitivity and specificity for RET fusions in NSCLC and nonmedullary TC FFPE [thyroid cancer formalin-fixed, paraffin-embedded tumor] specimens utilizing criteria established per a training set of known positive samples and negative samples. These results were validated via a larger set of NGS confirmed RET fusion–positive samples and negative samples covering RET fusion partners KIF5B, NCOA4, CCDC6, and ERC1.