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.

A case report of primary cardiac intimal sarcoma presenting with atrial fibrillation and a left atrial mass.

BACKGROUND: Intimal sarcoma is an exceedingly rare type of primary cardiac tumour. It is characterized by poorly differentiated spindle-shaped cells that can mimic smooth muscle and is strongly associated with MDM2 genetic amplification. Owing to its rarity and non-distinctive histological features, diagnosis remains a significant challenge. CASE SUMMARY: In this case report, we describe a case of primary cardiac intimal sarcoma in a 37-year-old woman who presented with atrial fibrillation (AF) and a left atrial mass. Despite having a histological sample from an excised left atrial mass, the diagnosis was not made until she presented with back pain secondary to metastatic disease to the spine. DISCUSSION: Primary cardiac intimal sarcoma is an extremely rare diagnosis. The mainstay management of intimal cardiac sarcoma is aggressive surgical resection. Unfortunately, the prognosis of cardiac sarcomas remains very poor, with a mean survival between 3 months and 1 year. This case of cardiac intimal sarcoma highlights the difficulty in establishing a diagnosis, particularly given the unusual presentation of AF.