Epstein–Barr virus (EBV)-associated diffuse large B-cell lymphoma not otherwise specified (DLBCL NOS) constitute a distinct clinicopathological entity in the current World Health Organization (WHO) classification. However, its genomic features remain sparsely characterized. Here, we combine whole-genome sequencing (WGS), targeted amplicon sequencing (tNGS), and fluorescence in situ hybridization (FISH) from 47 EBV + DLBCL (NOS) cases to delineate the genomic landscape of this rare disease. Integrated WGS and tNGS analysis clearly distinguished this tumor type from EBV-negative DLBCL due to frequent mutations in ARID1A (45%), KMT2A/KMT2D (32/30%), ANKRD11 (32%), or NOTCH2 (32%). WGS uncovered structural aberrations including 6q deletions (5/8 patients), which were subsequently validated by FISH (14/32 cases). Expanding on previous reports, we identified recurrent alterations in CCR6 (15%), DAPK1 (15%), TNFRSF21 (13%), CCR7 (11%), and YY1 (6%). Lastly, functional annotation of the mutational landscape by sequential gene set enrichment and network propagation predicted an effect on the nuclear factor κB (NFκB) pathway (CSNK2A2, CARD10), IL6/JAK/STAT (SOCS1/3, STAT3), and WNT signaling (FRAT1, SFRP5) alongside aberrations in immunological processes, such as interferon response. This first comprehensive description of EBV + DLBCL (NOS) tumors substantiates the evidence of its pathobiological independence and helps stratify the molecular taxonomy of aggressive lymphomas in the effort for future therapeutic strategies.

High-grade B-cell lymphoma accompanied with double/triple-hit MYC and BCL2 and/or BCL6 rearrangements (HGBLDH/ TH) poses a cytogenetically-defined provisional entity among aggressive B-cell lymphomas that is traditionally associated with unfavorable prognosis. In order to better understand the mutational and molecular landscape of HGBLDH/ TH we here performed whole-exome sequencing and deep panel next-generation sequencing of 47 clinically annotated cases. Oncogenic drivers, mutational signatures and perturbed pathways were compared with data from follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BL). We find an accumulation of oncogenic mutations in NOTCH, IL6/JAK/STAT and NFκB signaling pathways and delineate the mutational relationship within the continuum between FL/DLBCL, HGBL-DH/TH and BL. Further, we provide evidence of a molecular divergence between BCL2 and BCL6 rearranged HGBL-DH. Beyond a significant congruency with the C3/EZB DLBCL cluster in BCL2 rearranged cases on an exome-wide level, we observe an enrichment of the SBS6 mutation signature in BCL6 rearranged cases. Differential gene set enrichment and subsequent network propagation analysis according to cytogenetically defined subgroups revealed an impairment of TP53 and MYC pathway signaling in BCL2 rearranged cases, whereas BCL6 rearranged cases lacked this enrichment, but instead showed impairment of E2F targets. Intriguingly, HGBL-TH displayed intermediate mutational features considering all three aspects. This study elucidates a recurrent pattern of mutational events driving FL into MYC-driven BCL2-rearranged HGBL, unveiling the mutational pathogenesis of this provisional entity. Through this refinement of the molecular taxonomy for aggressive, germinal center-derived B-cell lymphomas, this calls into question the current World Health Organization classification system, especially regarding the status of MYC/BCL6- rearranged HGBL.

Patients with large B-cell lymphoma (LBCL) who experience relapsed disease after CD19-directed chimeric antigen receptor (CAR) T-cell (CAR-T) therapy have a poor prognosis. Bispecific antibodies (BsAbs) induce complete remissions in ∼35% of these cases. Hypothesizing overlapping LBCL-intrinsic resistance mechanisms as well as common poor prognosis predictors to CAR-T and BsAb therapy, we conducted a multicenter retrospective analysis including 92 patients with relapsed/refractory (R/R) LBCL treated with BsAbs after CAR-T failure. Overall response rate (ORR) was 43%, with a progression-free survival (PFS) of 2.8 months. Patients receiving BsAbs during early relapse (≤3 months) achieved a significantly worse outcome (ORR, 29%; PFS, 2.2 months) compared with patients with an intermediate (4-6 months; ORR, 54%; PFS, 3.7 months) or a late relapse (>6 months; ORR, 60%; PFS, 10.5 months). The benefit of later relapse was particularly notable in patients receiving BsAbs as first salvage therapy compared with those receiving a BsAb in subsequent lines (PFS not reached vs 2.7 months; overall survival not reached vs 9.1 months, respectively). In addition to early R/R state before BsAbs, elevated lactate dehydrogenase and higher International Prognostic Index score were significant predictors of poor outcomes to BsAb in multivariate Cox regression analyses. The finding that patients with early relapse after CAR-T respond particularly poorly to BsAb highlights the necessity for alternative treatment options in this high-risk patient cohort.

Background: Malignant neoplasms of the salivary glands are rare, and therapeutic options are limited. Results from recently published studies indicate a possible use for checkpoint inhibition in a subset of patients, but there are no established criteria for programme cell death ligand 1 (PD-L1) scoring in salivary gland carcinomas (SGCs). Methods: In this retrospective study, we present a cohort of 94 SGC patients with full clinical follow-up. We included 41 adenoid cystic carcinomas (AdCC), 21 mucoepidermoid carcinomas (MEC), 16 acinic cell carcinomas (ACC), 12 adenocarcinomas, not otherwise specified (AC, NOS), 2 epithelial-myoepithelial carcinomas (EMC), one salivary duct carcinoma (SDC), and one carcinoma ex pleomorphic adenoma (CA ex PA). Subsequent histopathological analysis was performed with special emphasis on the composition of the immune cell infiltrate (B-/T-lymphocytes). We assessed PD-L1 (SP263) on full slides by established scoring criteria: tumor proportion score (TPS), combined positivity score (CPS) and immune cell (IC) score. Results: We identified significantly elevated CD3+, TP, CP, and IC scores in AC, NOS compared to AdCC, MEC, and ACC. CPS correlated with node-positive disease. Moreover, AC, NOS displayed IC scores of 2 or 3 in the majority (67%) of cases (p = 0.0031), and was associated with poor prognosis regarding progression-free (PFS) (p < 0.0001) and overall survival (OS) (p < 0.0001). CPS correlated with strong nuclear or null p53 staining in AC, NOS but not in other SGCs. Long-lasting partial remission could be achieved in one AC, NOS patient who received Pembrolizumab as third-line therapy. Conclusions: The current study is the first to investigate the use of established scoring criteria for PD-L1 expression in malignant salivary gland tumors. Our findings identify unique characteristics for AC, NOS among the family of SGCs, as it is associated with poor prognosis and might represent a valuable target for immune checkpoint inhibition.