Molecular Feasibility of Gene Sequencing on Lymph Node Fine-Needle Cytology Samples of Non-Hodgkin Lymphoma

Non-Hodgkin lymphomas (NHL) are lymphoproliferative neoplasms with a heterogenous genetic landscape that require multiple assays to be characterized. Cytological samples are frequently utilized in the diagnosis of NHL. An RNA-based assay was utilized to detect translocations and identify mutations in fine-needle aspiration cytology (FNAC) samples of NHL. Fragmentation index and RNA concentration were evaluated in 54 FNAC and eight corresponding histological samples of NHL to establish first the material adequacy before sequencing. To sequence FusionPlex Lymphoma (ArcherDX, Boulder, USA), an anchored multiplex polymerase chain reaction-based RNA targeting 125 genes was used. The sequencing data processing was entirely carried out on the ArcherDX online platform. Mutations were detected in 21 of 62 samples (34%), and in 41 of 62 samples (66%), no genomic alterations were found. The FusionPlex assay detected five BCL6 translocations (three IGH-BCL6 and two EIF4A2-BCL6), six IGH-BCL2 translocations, two IGH-CCND1 translocations, two TP53 point mutations, two MYD88 mutation and four uncommon translocations (two EIF4E3-FOXP1, one TBL1XR1-TP63, one LOC105370537-FUT8). In eight out of eight cases, there was NGS (Next Generation Sequencing) results concordance between corresponding cytological and histological samples (100% concordance). FNAC samples of NHL are suitable for molecular assessment by NGS and FusionPlex Lymphoma assay is an effective method for this purpose. NGS allows the detection of mutations and the identification of translocations on cytological samples also with scanty diagnostic material.