Clinical validation of FusionPlex RNA-sequencing and its utility in the diagnosis and classification of hematologic neoplasms.

Recurrent gene rearrangements result in gene fusions that encode chimeric proteins, driving the pathogenesis of many hematologic neoplasms. The 5th Edition WHO classification and ICC 2022 include an expanding list of entities defined by such gene rearrangements. Therefore, sensitive and rapid methods are needed to identify a broad range of gene fusions for precise diagnosis and prognostication. In this study, we validated the FusionPlex pan-Heme panel analysis using anchored multiplex PCR/targeted RNA next-generation sequencing for routine clinical testing. Further, we assessed its utility in detecting gene fusions in myeloid and lymphoid neoplasms. The validation cohort of 61 cases demonstrated good concordance between the FusionPlex pan-Heme panel and other methodologies, including chromosome analysis, FISH, RT-PCR, and Sanger sequencing, with an analytic sensitivity and specificity of 95% and 100%, respectively. In an independent cohort of 28 patients indicated for FusionPlex testing, gene fusions were detected in 21 patients. The FusionPlex pan-Heme panel analysis reliably detected fusion partners and patient-specific fusion sequences, allowing accurate classification of hematologic neoplasms and the discovery of new fusion partners, contributing to a better understanding of the pathogenesis of the diseases.