[Plasmablastic lymphoma presenting with plasmacytosis and polyclonal hypergammopathy]

A 72-year-old woman presented with generalized lymphadenopathies and plasmacytosis accompanied by polyclonal hypergammopathy. 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) showed FDG accumulation in the systemic lymph nodes, spleen, and multiple bones. Human immunodeficiency virus antibody was negative. Lymph node histologic findings showed a monotonous population of plasma cells with a starry-sky appearance. The cells were positive for CD19, λ, and Epstein-Barr virus-encoded RNA, and negative for CD20 and CD56. The MIB-1 index was 80%. A diagnosis of plasmablastic lymphoma with plasmacytosis and polyclonal hypergammopathy was made, and complete metabolic response was achieved after six cycles of dose-adjusted-EPOCH therapy (etoposide, prednisolone, vincristine, cyclophosphamide, and doxorubicin).

Exploring TBL1XR1 and NCOR1 Expression in B-cell Lymphoma Subtypes: Interaction With DNA Damage Repair Genes

BACKGROUND/AIM

B-cell lymphomas are characterized by diverse genetic anomalies affecting B-cell differentiation. To expand targeted therapies, an in-depth grasp of the molecular dynamics in the germinal center (GC) is vital. Transducin β-like 1 X-linked receptor 1 (TBL1XR1) and nuclear receptor corepressor 1 (NCOR1) are instrumental within the GC, modulating myriad oncogenic pathways. Their prognostic roles in various cancers are established, yet their precise impact on B-cell lymphoma is elusive.

MATERIALS AND METHODS

Digital RNA quantification (Nanostring) of previously curated 188 B-cell lymphoma specimens across four subtypes, follicular lymphoma (FL), diffuse large B-cell lymphoma, not otherwise specified (DLBCL-NOS), primary testicular lymphoma (PTL), and plasmablastic lymphoma (PBL), was reanalyzed with focus on TBL1XR1 and NCOR1 expression, juxtaposing them with 730 ontogenically linked genes.

RESULTS

Notably, TBL1XR1 expression was significantly elevated in the PTL- ABC-subtype versus DLBCL-NOS- ABC-subtype (p<0.001), with no marked disparity in GCB-subtypes between them. The median TBL1XR1 expression was remarkably diminished in FL, yet, intriguingly, GCB-subtypes of DLBCL-NOS exhibited significantly enhanced expression compared to FL (p=0.001). In contrast, NCOR1's expression trajectory was consistent across DLBCL-NOS, PTL, and PBL. A strong inverse correlation between TBL1XR1 and NCOR1 was observed in PBL (p=0.001). Importantly, TBL1XR1's pronounced association with several DNA Damage repair (DDR) genes was noted suggesting influence on DNA repair. TBL1XR1-DDR gene signature was further validated employing a public data set of DLBCL-NOS.

CONCLUSION

Our exploratory findings unravel the expression patterns of TBL1XR1/NCOR1 in B-cell lymphoma variants. The TBL1XR1-DDR genes connection offers insights into potential DNA repair roles, paving avenues for innovative therapies in B-cell lymphomas.

Identification of Potential Therapeutic Targets for Plasmablastic Lymphoma Through Gene Expression Analysis: Insights into RAS and Wnt Signaling Pathways

Plasmablastic lymphoma (PBL) is a rare and aggressive B-cell lymphoma with overlapping characteristics with diffuse large B-cell lymphoma (DLBCL) and multiple myeloma. Hyperactive Wnt signaling derails homeostasis and promotes oncogenesis and chemoresistance in DLBCL and multiple myeloma. Evidence suggests active cross-talk between the Wnt and RAS pathways impacting metastasis in solid cancers in which combined targeted therapies show effective results. Recent genomic studies in PBL demonstrated a high frequency of mutations linked with the RAS signaling pathway. However, the role of RAS and Wnt signaling pathway molecule expression in PBL remained unknown. We examined the expression of Wnt and RAS pathway-related genes in a well-curated cohort of PBL. Because activated B cells are considered immediate precursors of plasmablasts in B cell development, we compared this data with activated B-cell type DLBCL (ABC-DLBCL) patients, employing NanoString transcriptome analysis (770 genes). Hierarchical clustering revealed distinctive differential gene expression between PBL and ABC-DLBCL. Gene set enrichment analysis labeled the RAS signaling pathway as the most enriched (37 genes) in PBL, including upregulating critical genes, such as NRAS, RAF1, SHC1, and SOS1. Wnt pathway genes were also enriched (n = 22) by gene set enrichment analysis. Molecules linked with Wnt signaling activation, such as ligands or targets (FZD3, FZD7, c-MYC, WNT5A, WNT5B, and WNT10B), were elevated in PBL. Our data also showed that, unlike ABC-DLBCL, the deranged Wnt signaling activity in PBL was not linked with hyperactive nuclear factor κB and B-cell receptor signaling. In divergence, Wnt signaling inhibitors (CXXC4, SFRP2, and DKK1) also showed overexpression in PBL. The high expression of RAS signaling molecules reported may indicate linkage with gain-in-function RAS mutations. In addition, high expression of Wnt and RAS signaling molecules may pave pathways to explore benefiting from combined targeted therapies, as reported in solid cancer, to improve prognosis in PBL patients.

Histologic transformation of follicular lymphoma: pathologists’ viewpoint

Outcomes of patients with histologic transformation (HT) of follicular lymphoma (FL) have been believed to be poor. The most common histologic subtype of transformation from FL is diffuse large B-cell lymphoma (DLBCL), which accounts for 90% of the cases, and the remaining 10% of the cases include classic Hodgkin lymphoma, high-grade B-cell lymphoma, plasmablastic lymphoma, B-acute lymphoblastic leukemia/lymphoma, histiocytic/dendritic cell sarcoma, and anaplastic large cell lymphoma-like lymphoma. Because the histologic criteria for the diagnosis of DLBCL transformed from FL are unclear, convenient histopathological criteria for HT are required. One of the proposed criteria of HT from our institute is the presence of diffuse architecture with a proportion of large lymphoma cells of ≥20%, and for challenging cases, Ki-67 index ≥50% is used as a reference. Patients with HT to non-DLBCL have poorer outcomes than those with HT to DLBCL; thus, rapid and accurate histologic diagnosis is desired. In this review, we discussed the recent literatures describing the histopathologic variety and proposal of definition of HT.

Tumor Thrombus on 18F-FDG PET/CT in Stage IV Plasmablastic Lymphoma

ABSTRACT

A 71-year-old woman with a history of back pain and recent weight loss presented to the emergency department with hematuria. A CT scan was performed and showed left retroperitoneal mass with left renal vein thrombus extended to the vena cava. Tumor biopsy revealed plasmablastic lymphoma. Staging with 18F-FDG PET/CT scan was performed and revealed pulmonary, hepatic, and left supraclavicular lymph node extension. The left retroperitoneal mass showed intense FDG uptake and was associated with widespread tumor thrombus in the peripheral abdominal veins. Differentiating tumor thrombus from bland thrombosis has a significant impact on patient's management.