Simultaneous Identification of Cell of Origin, Translocations, and Hotspot Mutations in Diffuse Large B-Cell Lymphoma Using a Single RNA-Sequencing Assay

Objectives: Diffuse large B-cell lymphoma (DLBCL) is an aggressive non-Hodgkin lymphoma with a heterogenous genetic landscape that can require multiple assays to characterize We reviewed a 1-step RNA-based assay to determine cell of origin (COO), detect translocations and identify mutations and to assess the role of the assay in diagnosis. Methods: Using a single custom Archer FusionPlex Lymphoma panel, we performed anchored multiplex polvmerase chain reaction-based RNA sequencing on 41 cases of & novo DLBCL. Each case was subclassified by COO, and gene fusions and hotspot mutations were identified Thefrndings were then compared with COO classification by the Hans immunohistocItemical algorithm and NanoString technology, cytogenetics, and fluorescence in situ hybridization results. Results: Concordant COO classification by the FusionPlex panel and NanoString was observed in 35 of 41 cases (85.3%), with NanoString and Hans concordant in 33 of 41 cases (80.5%) and FusionPlex and Hans concordant in 33 of 41 cases (80.5%). The FusionPlex assay also detected 6 of 11 BCL6 translocations (4 cryptic), 2 of 3 BCL2 translocations and 2 of 4 MYC translocations. Mutations were detected in lymphoma-related genes in 24 of 41 cases. Conclusion: This FusionPlex assay offers a single method for COO classification, mutation detection, and identification of important translocations in DLBCL. Although not replacing traditional testing, it could offer useful data when limited tissue is available

Automated summary

The study used a one-step RNA-based method to classify DLBCL and identify mutations, achieving consistent results with traditional testing methods. The FusionPlex assay showed high accuracy in COO classification, translocation detection, and mutation identification.