Variables significant for survival analysis in univariate analysis

Mantle cell lymphoma (MCL) is a rare but often aggressive type of B cell lymphoma with a high risk of relapse. To explore intratumoral clonal diversity and tumor evolution related to disease relapse, we integrate single-cell RNA and B cell receptor sequencing with whole-genome sequencing in 20 diagnosed/untreated and/or relapsed samples from 11 MCL patients. Our results reveal significant intratumor heterogeneity in MCL already at diagnosis. We further show that the evolutionary paths during disease progression for each patient are unique, where minor clones present at diagnosis may acquire different mutations and copy-number variations and/or migrate to various microenvironments. Despite significant interpatient heterogeneity, recurrent genetic and transcriptomic changes in tumor cells affecting key signaling pathways, along with alterations involved in the tumor microenvironment, are also observed during disease progression. Taken together, our findings elucidate the diverse and dynamic tumor-immune evolution processes associated with disease progression and relapse in MCL.

MDSRS+ event free survival (EFS) stratified by estimated MEP percentage in the four genetic subgroups (A-D).

UMAP plot of MDSRS+ bone marrow CD34 mononuclear cells transcriptomes. Each point is one patient, overlaid with results from unsupervised clustering.

Cumulative proportion of principal components derived from principal component analysis. The first 14 explain 2/3 of the total variability.

Session 2 of the 2024 European Association for Haematopathology/Society for Hematopathology lymphoma workshop was dedicated to atypical lymphoproliferations in association with germline genetic variants. The first group of cases were lymphoproliferations occurring in the context of primary immunodeficiencies (PID), a heterogeneous group of diseases with increasing incidence and number of different diseases due to better recognition. The workshop contained a spectrum of different PIDs and associated lymphoproliferations with autoimmune lymphoproliferative syndrome, activated phosphoinositide 3-kinase delta syndrome, ataxia-telangiectasia and common variable immune deficiency being the most common. Both children and adults were affected, and the diagnosis of an underlying PID often required a high index of suspicion and correlation with clinical presentation and immunological/ infectious workup. Recognition of a PID allows specific treatment and can influence the interpretation of lymphoproliferations occurring in this context. The spectrum of lymphoproliferations ranged from reactive to overt lymphoma, both EBV-positive and -negative. In a subset of cases, it was very difficult or impossible to establish the boundary between reactive and neoplastic in the context of a PID. The second group represented a heterogeneous group of lymphoproliferations in the context of mutations in germline haematopoietic malignancy risk genes, without associated immunodeficiency. It was often difficult to determine if the genetic defect and the lymphoproliferation were causally related or coincidental, especially if the patient was also treated for non-lymphoid conditions. This is a rapidly evolving field in which future studies are expected to shed more light on the relationship between germline mutations and lymphoid malignancy.

– Results from Gene Ontology enrichment analysis (molecular function dataset) for the top 250 contributors of principal component 1 (PC1)

Treatment. Number of cases that underwent to each treatment category and the associated hazard-ratio for death is reported for each genetic subgroup and for the whole cohort.

Clonal hierarchy analysis of SF3B1-SRSF2 co-mutated cases. A. Results from the hierarchical rank analysis of mutations detected by DNAseq in the 4 cases harboring both SF3B1 and SRSF2 mutation using Pyclone. The analysis was also performed using DPClust, which provided converging results (data not shown). Tumor cell fraction (axes) for each detected clone and its 95% confidence interval (dot size) is represented in a scatter-plot, using different color according to the cluster driving mutation (SF3B1, red; SRSF2, blue; other drivers, gray). SF3B1 dominancy in MDS392 and MDS 640, together with the SRSF2 large clone size are suggestive of both splicing factor mutations in the same clone. On the contrary, MDS694 and MDS965 had a dominant SF3B1 clone associated with a very little and probably independent SRSF2 secondary clone. B. Results from single-cell derived colony-forming unit (CFU) genotyping confirming the concurrent double splicing factor mutations within the same clone in patient MDS382 and MDS640. CFU experiment was not carried out for the other two cases because of the very low probability of SF3B1/SRSF2 double positive clone identification, as already suggested by current data in the literature related to the presence of SF3B1K700E mutation (ref. 1).

Prognostic effect of genomic and transcriptomic analyses on MDSRS+ outcome. Overall survival (OS) stratified by genomic (A), transcriptomic classification (B) and estimated MEP percentage (C) in all MDSRS+ (A-C) and MDS-RS-SLD/MLD only (D-F). Multivariable Cox proportional hazard model for OS in all MDSRS+ including age, IPSS-mol score and estimated MEP percentage as continuous variables (G). OS stratified by estimated MEP percentage and IPSS-mol risk category (full representation of the 6 IPSS-mol categories shown in Supplemental Figure 21B).

Castleman disease (CD) is an intriguing and complicated group of local and systemic disorders mainly affecting lymph nodes with heterogeneous presentation and therapeutic needs. These disorders were the topic of Session 1 of the Lymphoma Workshop at the 2024 EA4HP in Dubrovnik, Croatia. In this report, we summarize the features of the 85 submitted cases and review the differential diagnosis, pitfalls, and advances for all CD subtypes. Specifically, the molecular landscape of unicentric CD and its relationship with follicular dendritic cell proliferations and indolent T-lymphoblastic proliferation will be discussed. The spectrum of idiopathic multicentric CD (MCD), TAFRO syndrome, as well as the clinical and histopathological peculiarities of POEMS-CD, is reviewed. Cases of Kaposi sarcoma-associated herpesvirus/human herpesvirus 8 (KSHV/HHV8) + MCD were the most complicated and well demonstrated the difficulties and overlaps in the differential diagnosis of KSHV/HHV8 + lymphoproliferative disorders. Finally, the important topic of CD mimickers will be addressed, demonstrating how the integration of clinical, laboratory, histopathological, and molecular data is mandatory to confirm a diagnosis of CD and how to distinguish it from the many neoplastic, autoimmune, and infective mimickers.

Transcriptomic impact on SF3B1 mutant MDS and low blasts outcome. Overall survival (OS) and Event Free Survival (EFS) stratified by transcriptomic classification (A-B) and estimated MEP percentage (C-D), respectively, in SF3B1 mutant MDS and low blasts, as defined according to ICC and WHO 2022 classification.

Demographic and clinical features of cases and controls included into the study.

EMK and IMP signature validation on HSPC sorted populations. Differential gene expression analysis across MDSRS+ with EMK profile, MDSRS- with IMP profile and NBM (3 cases each) according to Lin marker expression. Differential expressed genes (row) between EMK and IMP groups were selected. Each row represents a gene, and each column represents a sample. Design comparison (case) and sorted population (condition) are shown as covariates.

List of differentially expressed genes associated with EMK, INT and IMP profile.

Biological insights beyond the cell-of-origin (COO) classification can support clinical management in diffuse large B-cell lymphoma (DLBCL). We investigated if Toll-like receptor 9 (TLR9) expression could serve as a prognostic marker in DLBCL. TLR9 gene expression was analysed in four publicly available cohorts (n = 2474), and protein expression was investigated in germinal centre B-cell (GCB) and activated B-cell (ABC) DLBCL cell lines. Next, TLR9 protein expression was analysed in 120 diagnostic samples from R-CHOP-treated patients with relapsed/refractory disease (poor outcome, n = 50) or in complete remission (good outcome, n = 70). Associations were evaluated using logistic regression, estimating odds ratios (OR) and 95

The boundaries between neoplastic and reactive lymphoproliferations were discussed during the 2024 European Association for Haematopathology/Society for Hematopathology workshop in Dubrovnik, Croatia. Session 5 focused on indolent lymphoid neoplasms and clonal lymphoproliferations. Seventy-two cases were submitted, representing good examples of indolent lymphomas and lymphoproliferative disorders (LPD) and their diagnostic challenges. The morphologic spectrum of primary cutaneous marginal zone lymphoma/lymphoproliferation (PC-MZL/PC-MZLPD) was discussed. PC-MZL/PC-MZLPD is divided in the immunoglobulin heavy chain switched-type and non-switched-type with some clinicopathological differences. The overlapping features between PC-MZL/PC-MZLPD and PC-CD4 + T-cell LPD were highlighted. The criteria for the diagnosis of indolent T-lymphoblastic proliferation (iT-LBP) were reviewed. Indolent T-cell lymphoproliferation of the gastrointestinal tract (iT-LPD-GI) is a rare clonal, non-destructive, and non-epitheliotropic T-cell LPD occurring in adults with a male predominance. The cases submitted to the workshop revealed clinicopathological heterogeneity. Unusual features like infiltration of the complete intestinal wall, mesenteric lymph node involvement, and splenomegaly were observed. A novel group of PD1 + /CD4 + indolent cases with intestinal tropism and dissemination to blood, bone marrow, lymph node, and skin was identified. Other indolent clonal B- and T-cell LPDs were discussed including transient, clonal CD8 + T-cell proliferations, usually the result of immune-mediated cytotoxic T-cell response to virus or neoantigens, and the recently described follicle center lymphoma (FLC) of the lower female genital tract. The increasing awareness of the existence of indolent LPDs should avoid unnecessary treatments. In this report, novel findings, recommendations for diagnosis, open questions, and diagnostic challenges raised by the cases submitted to the workshop will be discussed.