Impact of etoposide and ASCT on survival among patients aged <65 years with stage II to IV PTCL: a population-based cohort study.

Patients aged <65 years with peripheral T-cell lymphoma (PTCL) are treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP). Although the addition of etoposide (CHOEP) and consolidation with autologous stem cell transplantation (ASCT) are preferred in some countries, randomized trials are lacking. This nationwide population-based study assessed the impact of etoposide and ASCT on overall survival (OS) among patients aged 18 to 64 years with stage II to IV anaplastic large-cell lymphoma (ALCL), angioimmunoblastic T-cell lymphoma (AITL), or PTCL not otherwise specified (NOS) diagnosed between 1989 and 2018 using the Netherlands Cancer Registry. Patients were categorized into 2 calendar periods, representing pre- and post-eras of etoposide and ASCT, respectively. A total of 1427 patients were identified (ALCL, 35%; AITL, 21%; and PTCL NOS, 44%). OS increased from 39% in the period from 1989 to 2009 to 49% in the period of 2009 to 2018 (P < .01). Five-year OS was superior for patients treated with CHOEP vs CHOP (64% and 44%, respectively; P < .01). When adjusted for subtype, International Prognostic Index score, and ASCT, the risk of mortality was similar between the 2 groups, except for patients with ALK+ ALCL, for whom the risk of mortality was 6.3 times higher when treated with CHOP vs CHOEP. Patients undergoing consolidation with ASCT had superior 5-year OS of 81% compared with 39% for patients not undergoing ASCT (P < .01), regardless of whether complete remission was achieved. In patients aged <65 years with advanced-stage ALK- ALCL, AITL, or PTCL, the use of ASCT consolidation, but not the addition of etoposide, was associated with improved OS.

Outcome of combined modality treatment in first-line for stage I(E) peripheral T-cell lymphoma; a nationwide population-based cohort study from the Netherlands.

Peripheral T-cell lymphomas (PTCL) comprise a heterogeneous group of mature T-cell neoplasms with an unfavorable prognosis; presentation with stage I(E) disease is uncommon. In clinical practice, an abbreviated chemotherapy treatment regimen combined with radiotherapy (combined modality treatment [CMT]) is commonly used, although evidence from clinical trials is lacking. The aim of this nationwide population-based cohort study is to describe first-line treatment and outcome of patients with stage I(E) PTCL. All newly diagnosed patients ≥18 years with stage I(E) anaplastic large cell lymphoma (ALCL), angioimmunoblastic T-cell lymphoma (AITL) and peripheral T-cell lymphoma NOS (PTCL not otherise specified [NOS]) in 1989-2020 were identified in the Netherlands Cancer Registry. Patients were categorized according to treatment regimen, i.e., chemotherapy (CT), radiotherapy (RT), CMT, other therapy and no treatment. The primary endpoint was overall survival (OS). Patients with stage I(E) ALCL, AITL and PTCL NOS (n=576) were most commonly treated with CMT (28%) or CT (29%), 2% underwent SCT. RT only was given in 18%, and 8% received other therapy and 16% no treatment. Overall, the 5-year OS was 59%. According to subtype, 5-year OS was superior for ALCL as compared to PTCL NOS and AITL (68% vs. 55% and 52%, respectively; P=0.03). For patients treated with CMT, 5-year OS was significantly higher (72%) as compared to patients treated with either CT or RT alone (55% and 55%, respectively; P<0.01). In multivariable analysis, age per year increment (hazard ratio [HR] =1.06, 95% confidence interval [CI]: 1.05-1.07), male sex (HR=1.53, 95% CI: 1.23-1.90), and CT, or no treatment (HR=1.64, 95% CI: 1.21-2.21, and HR=1.55, 95% CI: 1.10-2.17, respectively) were associated with a higher risk of mortality. For stage I(E) ALCL, AITL and PTCL NOS, 5-year OS is 59%, comparing favorably to historical outcome in advanced-stage disease. Superior outcome estimates were observed in patients treated with CMT.

When increasing risk perception does not work. Using behavioral psychology to increase smoke alarm ownership.

The central question of our study is which determinants drive smoke alarm ownership and intention to purchase one, and whether we can increase smoke alarm ownership by addressing these determinants in a communication-based intervention. We first made an inventory of possible determinants for smoke alarm prevention by consulting prominent prevention behavior theories protection motivation theory and Health Belief Model and other relevant literature. We expanded this list of determinants based on interviews (n = 15) and used survey data representative for the Netherlands to decide to focus on smoke alarm ownership (rather than installation or maintenance). We then tested the determinants of smoke alarm ownership and buying intention in a survey (n = 622). Based on these results, we ran an A/B test (n = 310) of two messages to stimulate smoke alarm ownership: one emphasized the determinants we found to be strong predictors in the survey (know-how, social norm, annoyance) and one emphasized typical determinants that are often addressed in campaigns but were poor predictors in the survey (vulnerability, severity, benefits). Results showed that the message based on the strong determinants resulted in a significant increase in smoke alarm ownership (9.1%) compared to the control group (0.9%; p = 0.027), while the message using the typical determinants did not lead to significant effects. Taken together, our results give a promising direction for interventions to increase smoke alarm ownership, and above all, show that a comprehensive problem analysis for a specific target behavior is a necessary step to induce behavioral change.

Clinical, histopathological and prognostic features of primary cutaneous acral CD8+ T-cell lymphoma and other dermal CD8+ cutaneous lymphoproliferations: results of an EORTC Cutaneous Lymphoma Group workshop.

BACKGROUND: The differential diagnosis of atypical dermal nonepidermotropic CD8+ lymphocytic infiltrates includes a heterogeneous spectrum of lymphoproliferations with overlapping histological and phenotypic features, but divergent clinical manifestations and prognoses. As these neoplasms are rare, more data on their clinicopathological presentation and course are needed. OBJECTIVES: To assess the clinical, histological and immunophenotypic features; outcomes of; and differences between dermal CD8+ lymphoproliferations. METHODS: Retrospective analysis of a series of 46 patients and biopsies by the international EORTC Cutaneous Lymphoma Group. RESULTS: The dermal CD8+ lymphoproliferations (n = 46) could be assigned to one of three groups: (i) cutaneous acral CD8+ T-cell lymphoma (n = 31), characterized mostly by a solitary nodule arising at acral sites, a monotonous dermal infiltrate of small-to-medium-sized CD8+ lymphocytes with a characteristic dot-like pattern of CD68, a low proliferation rate and an excellent prognosis; (ii) primary cutaneous CD8+ peripheral T-cell lymphoma, unspecified/NOS (n = 11), presenting with one or multiple rapidly evolving tumours, mostly medium-sized pleomorphic CD8+ tumour cells with expression of several cytotoxic markers, and high proliferative activity; and (iii) cutaneous CD8+ lymphoproliferations (n = 4), associated with congenital immunodeficiency syndromes in two patients with persisting localized or disseminated violaceous to brownish plaques on the extremities, a histiocyte-rich infiltrate of mostly small CD8+ lymphocytes with subtle atypia and a protracted course; and papular CD8+ eruptions in two patients with acquired immunosuppression. CONCLUSIONS: A constellation of distinct clinical, histopathological and phenotypic features allows discrimination and assignment of dermal CD8+ infiltrates into distinct disease entities. Primary cutaneous acral CD8+ lymphoma, assigned a provisional category in current lymphoma classifications, is a distinct and reproducible entity. A correct diagnosis is essential to avoid unnecessarily aggressive treatment for indolent CD8+ lymphoproliferations and to identify cases with underlying immuno-deficiency or potential for dismal outcome.

Determinants of Domestic Risk Prevention Behavior: The Importance of Separating Effects Within-Persons and Between-Persons.

The effects of vulnerability, severity, costs, effort, and effectiveness on prevention behavior, derived from protection motivation theory and the health belief model, have been extensively tested in the literature and have all been shown to predict rather well. In this study we test the effects of these determinants in a new context: the domestic risk prevention domain. The specific behaviors under study are related to the risks of burglary, fire, and water damage. In addition to previous studies, our multilevel research design allows us to evaluate which differences in the performance of domestic prevention behavior can be attributed to differences between persons and which to differences between behaviors within persons. Our results show that all determinants are relevant predictors for domestic risk prevention behavior. Disentangling the within-person and between-person effects shows that prevention behavior depends more on the relative evaluation of the prevention behavior determinants for a given person (e.g., a person perceives a smoke alarm to be more effective than antiburglar strips), than on the differences between persons regarding the general perception of these determinants (e.g., some persons find prevention behaviors in general more effective than other persons). To increase the performance of domestic risk prevention behaviors, we advise that interventions should focus on increasing a person's perception of risks and prevention behaviors relative to other risks and prevention behaviors rather than focusing on changing people's general perceptions of all risks and behaviors or focusing on specific target groups.

Plaque stage folliculotropic mycosis fungoides: histopathologic features and prognostic factors in a series of 40 patients.

BACKGROUND: Folliculotropic mycosis fungoides (FMF) is a distinct variant of mycosis fungoides. Recent studies recognized indolent and aggressive subgroups of FMF, but there is controversy how patients presenting with plaques should be classified. The present study describes the histopathologic features of 40 FMF plaques. The aim of the study was to identify risk factors for disease progression and poor outcome in this group. METHODS: Clinical, histopathological, and immunophenotypical data from 40 patients with plaque stage FMF were reviewed and analysed for risk factors for disease progression and survival. RESULTS: After a median follow-up of 80 months, disease progression occurred in 20 of 40 patients. Percentage of atypical cells, cell size, percentage of Ki-67+ cells, and co-existent interfollicular epidermotropism, but not the extent of perifollicular infiltrates, were associated with disease progression and reduced survival, while extensive follicular mucinosis was associated with increased survival. CONCLUSIONS: This study underlines that FMF patients presenting with plaques represent a heterogeneous group and that a subgroup of these patients may have an indolent clinical course. It further shows that histological examination is a valuable tool to differentiate between indolent and aggressive disease.

Folliculotropic mycosis fungoides presenting with a solitary lesion: Clinicopathological features and long-term follow-up data in a series of 9 cases.

BACKGROUND: Folliculotropic mycosis fungoides (FMF) is a distinct variant of mycosis fungoides, which in rare cases may present with a solitary lesion. Reported cases describe an excellent prognosis, but follow up was generally short. Herein, clinicopathologic characteristics, long-term follow-up data of 9 patients with solitary FMF are presented and differential diagnosis is discussed. METHODS: From a cohort of 203 patients with FMF, 9 cases with solitary FMF were selected. Clinical data and histological sections obtained at diagnosis and during follow up were reviewed. RESULTS: Skin lesions, in all patients located on the head, went into complete remission after treatment with radiotherapy (6 cases) or topical steroids (1 case) or regressed spontaneously (2 cases). After a median follow up of 89 months (range 51-203 months), 5 patients were still in complete remission, 2 patients had developed multiple skin relapses, while 2 patients had progressed to extracutaneous and fatal disease. Histologically, all patients showed marked folliculotropism, associated with syringotropism (4 cases) and/or follicular mucinosis (5 cases). Large-cell transformation was observed at presentation (2 cases) and during follow-up (3 cases). CONCLUSIONS: Long-term follow-up data indicate that patients with solitary FMF do not always have an indolent clinical course and therefore require long-term follow up.

Differential expression of TOX by skin-infiltrating T cells in Sézary syndrome and erythrodermic dermatitis.

BACKGROUND: The histopathologic differentiation between Sézary syndrome (SS) and erythrodermic dermatitis may be extremely difficult. In this immunohistochemical study, it was investigated if thymocyte selection-associated high mobility group box protein (TOX) and C-MYC can be used as additional diagnostic markers to differentiate between SS and erythrodermic dermatitis. METHOD: Paraffin-embedded skin biopsies from 15 SS patients and 17 erythrodermic dermatitis patients were stained and scored for TOX or C-MYC expression. RESULTS: Strong nuclear staining for TOX in more than 50% of skin-infiltrating T cells was observed in 13 of 15 (87%) SS cases, whereas erythrodermic dermatitis cases showed weak nuclear staining in 11-50% (median: 25%) of the T cells; strong nuclear staining as found in SS was never observed in erythrodermic dermatitis. No significant differences in C-MYC expression between SS and erythrodermic dermatitis were found. In most patients of both groups, percentages of C-MYC positive-cells varied between less than 10 and 25% of skin-infiltrating T cells. CONCLUSION: Our results suggest that strong expression of TOX in more than 50% of skin-infiltrating T cells in erythrodermic skin is a useful marker in the differentiation between SS and erythrodermic dermatitis, whereas staining for C-MYC does not contribute to differential diagnosis.

Prognostic factors in transformed mycosis fungoides: a retrospective analysis of 100 cases.

Large cell transformation (LCT) in mycosis fungoides (MF) is generally associated with an aggressive clinical course and poor survival, requiring aggressive therapeutic approach. However, a proportion of cases may follow an indolent clinical course. To identify prognostic factors, we analyzed the prognostic relevance of clinical, histologic, and immunophenotypical features in a large cohort of transformed MF patients, including 75 patients with only skin lesions, 19 patients with LCT in skin and lymph nodes, and 6 patients with LCT in lymph nodes only. Multivariate analysis of the total group showed that CD30 negativity, folliculotropic MF, extent of skin lesions and extracutaneous transformation were associated with reduced disease-specific survival (DSS) and, except for CD30 negativity and folliculotropic MF, also overall survival. In a multivariate analysis of 75 patients with only skin lesions at the time of LCT, CD30 negativity, folliculotropic MF and extent of skin lesions were independent parameters for both DSS and overall survival. Using the most discriminating parameters as a prognostic index, in both study groups differences in DSS between patients with 0-1 unfavorable prognostic factor(s) and ≥ 2 unfavorable prognostic factors were statistically significant (P < .001). This prognostic index may be helpful in predicting prognosis and selecting the most appropriate treatment in patients with transformed MF.

Programmed death-1 expression in cutaneous B-cell lymphoma.

BACKGROUND: Numbers of programmed death-1 (PD-1) positive T cells have prognostic significance in some types of nodal B-cell lymphomas, but data on PD-1 expression in cutaneous B-cell lymphoma (CBCL) are few. In this study we determined the expression and distribution of PD-1 on neoplastic B cells and reactive T cells in skin sections from primary CBCLs. METHODS: By means of immunohistochemical staining, PD-1 expression was investigated in skin biopsies from 10 patients with primary cutaneous marginal zone lymphoma (PCMZL), 18 patients with primary cutaneous follicle center lymphoma (PCFCL) and 12 patients with primary cutaneous diffuse large B-cell lymphoma-leg type (PCDLBCL-LT). RESULTS: Neoplastic B cells were negative for PD-1 in all cases, except for two cases of PCDLBCL-LT. The frequency of PD-1(+) T cells was significantly higher in PCFCL than in PCMZL and PCDLBCL-LT, accounting for 20, 10 and 3% of the total number of infiltrating cells, and 60, 20 and 15% of the total number of CD3(+) T cells, respectively. CONCLUSIONS: PD-1 is rarely expressed by the neoplastic B cells in CBCL. High percentages of PD-1(+) T cells, particularly if found outside germinal centers, support a diagnosis of PCFCL.

Treatment strategies and outcome in relapsed peripheral T-cell lymphoma: results from the Netherlands Cancer Registry.

Optimal treatment in patients with refractory or relapsed peripheral T-cell lymphomas (R/R T-NHL) is unknown. In this population-based study, outcome in R/R PTCL not otherwise specified (PTCL NOS), angioimmunoblastic T-cell lymphoma (AITL) and ALK+ and ALK- anaplastic large cell lymphoma (ALCL) was evaluated. Patients with PTCL NOS, AITL, ALK+ ALCL and ALK- ALCL (≥18 years) diagnosed in 2014-2019 were identified using the Netherlands Cancer Registry. Endpoints were overall response rate (ORR), progression-free survival (PFS) and overall survival (OS). The 2-year PFS of 821 patients was 57%. Among 311 patients with a relapse, 243 received second-line treatment: 44% salvage chemotherapy, 20% brentuximab vedotin (BV) and 36% other treatment. In third-line, BV was most commonly used (38%). ORR following second-line treatment was 47%. Two-year PFS and OS after relapse were 25% and 34%, respectively. Risk of second relapse was negatively affected by early relapse (<12 months post-diagnosis), while BV reduced this risk compared to salvage chemotherapy (HR 0.55; 0.35-0.87; p=0.01). Reduced risk of relapse was independent of histological subtype. The best outcomes were observed for patients treated with salvage chemotherapy receiving consolidative autologous and allogeneic stem cell transplantation (SCT) (2-year OS 68%), patients treated with BV achieving a second complete remission (2-year OS 74%) and patients with allogeneic SCT (2-year OS 60%). The risk of second relapse was significantly lower for R/R T-NHL patients treated with BV compared to patients treated with salvage chemotherapy, and this was irrespective of subtype. Therefore, the use of salvage chemotherapy for R/R T-NHL patients is challenged.

Real-world routine diagnostic molecular analysis for TP53 mutational status is recommended over p53 immunohistochemistry in B-cell lymphomas.

Previous studies in patients with mature B-cell lymphomas (MBCL) have shown that pathogenic TP53 aberrations are associated with inferior chemotherapeutic efficacy and survival outcomes. In solid malignancies, p53 immunohistochemistry is commonly used as a surrogate marker to assess TP53 mutations, but this correlation is not yet well-established in lymphomas. This study evaluated the accuracy of p53 immunohistochemistry as a surrogate marker for TP53 mutational analysis in a large real-world patient cohort of 354 MBCL patients within routine diagnostic practice. For each case, p53 IHC was assigned to one of three categories: wild type (staining 1-50% of tumor cells with variable nuclear staining), abnormal complete absence or abnormal overexpression (strong and diffuse staining > 50% of tumor cells). Pathogenic variants of TP53 were identified with a targeted next generation sequencing (tNGS) panel. Wild type p53 expression was observed in 267 cases (75.4%), complete absence in twenty cases (5.7%) and the overexpression pattern in 67 cases (18.9%). tNGS identified a pathogenic TP53 mutation in 102 patients (29%). The overall accuracy of p53 IHC was 84.5% (95% CI 80.3-88.1), with a robust specificity of 92.1% (95% CI 88.0- 95.1), but a low sensitivity of 65.7% (95% CI 55.7-74.8). These results suggest that the performance of p53 IHC is insufficient as a surrogate marker for TP53 mutations in our real-world routine diagnostic workup of MBCL patients. By using p53 immunohistochemistry alone, there is a significant risk a TP53 mutation will be missed, resulting in misevaluation of a high-risk patient. Therefore, molecular analysis is recommended in all MBCL patients, especially for further development of risk-directed therapies based on TP53 mutation status.

Cell-of-origin classification using the Hans and Lymph2Cx algorithms in primary cutaneous large B-cell lymphomas.

Primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL-LT) and primary cutaneous follicle center lymphoma with a diffuse population of large cells (PCFCL-LC) are both primary cutaneous B-cell lymphomas with large-cell morphology (CLBCL) but with different clinical characteristics and behavior. In systemic diffuse large B-cell lymphoma, not otherwise specified (DLBCL-NOS), gene-expression profiling (GEP) revealed two molecular subgroups based on their cell-of-origin (COO) with prognostic significance: the germinal center B-cell-like (GCB) subtype and the activated B-cell-like (ABC) subtype. This study investigated whether COO classification is a useful tool for classification of CLBCL. For this retrospective study, 51 patients with PCDLBCL-LT and 15 patients with PCFCL-LC were analyzed for their COO according to the immunohistochemistry-based Hans algorithm and the NanoString GEP-based Lymph2Cx algorithm. In PCFCL-LC, all cases (100%) classified as GCB by both Hans and Lymph2Cx. In contrast, COO classification in PCDLBCL-LT was heterogeneous. Using Hans, 75% of the PCDLBCL-LT patients classified as non-GCB and 25% as GCB, while Lymph2Cx classified only 18% as ABC, 43% as unclassified/intermediate, and 39% as GCB. These COO subgroups did not differ in the expression of BCL2 and IgM, mutations in MYD88 and/or CD79B, loss of CDKN2A, or survival. In conclusion, PCFCL-LC uniformly classified as GCB, while PCDLBCL-LT classified along the COO spectrum of DLBCL-NOS using the Hans and Lymph2Cx algorithms. In contrast to DLBCL-NOS, the clinical relevance of COO classification in CLBCL using these algorithms has limitations and cannot be used as an alternative for the current multiparameter approach in differentiation of PCDLBCL-LT and PCFCL-LC.

Impact of rituximab on treatment outcomes of patients with angioimmunoblastic T-cell lymphoma; a population-based analysis.

BACKGROUND: Patients with angioimmunoblastic T-cell lymphoma (AITL) are treated with cyclophosphamide, doxorubicin, vincristine and prednisone with or without etoposide (CHO(E)P). In the majority of cases, Epstein-Barr virus (EBV)-positive B-cells are present in the tumour. There is paucity of research examining the effect of rituximab when added to CHO(E)P. In this nationwide, population-based study, we analysed the impact of rituximab on overall response rate (ORR), progression-free survival (PFS) and overall survival (OS) of patients with AITL. METHODS: Patients with AITL diagnosed between 2014 and 2020 treated with ≥one cycle of CHO(E)P with or without rituximab were identified in the Netherlands Cancer Registry. Survival follow-up was up to 1st February 2022. Baseline characteristics, best response during first-line treatment and survival were collected. PFS was defined as the time from diagnosis to relapse or to all-cause-death. OS was defined as the time from diagnosis to all-cause-death. Multivariable analysis for the risk of mortality was performed using Cox regression. FINDINGS: Out of 335 patients, 146 patients (44%) received R-CHO(E)P. Rituximab was more frequently used in patients with a B-cell infiltrate (71% versus 89%, p < 0·01). The proportion of patients who received autologous stem cell transplantation (ASCT) was similar between CHO(E)P and R-CHO(E)P (27% versus 30%, respectively). The ORR and 2-year PFS for patients who received CHO(E)P and R-CHO(E)P were 71% and 78% (p = 0·01), and 40% and 45% (p = 0·12), respectively. The 5-year OS was 47% and 40% (p = 0·99), respectively. In multivariable analysis, IPI-score 3-5, no B-cell infiltrate and no ASCT were independent prognostic factors for risk of mortality, whereas the use of rituximab was not. INTERPRETATION: Although the addition of rituximab to CHO(E)P improved ORR for patients with AITL, the PFS and OS did not improve.

Genetic Stability of Driver Alterations in Primary Cutaneous Diffuse Large B-Cell Lymphoma, Leg Type and Their Relapses: A Rationale for the Use of Molecular-Based Methods for More Effective Disease Monitoring.

Primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL-LT) is a rare, aggressive cutaneous lymphoma with a 5-year disease-specific survival of only ~55%. Despite high response rates to initial immune-polychemotherapy, most patients experience a disease relapse. The genetic evolution of primary and relapsed/refractory disease has only scarcely been studied in PCDLBCL-LT patients. Therefore, in this retrospective cohort study, 73 primary/pre-treatment and relapsed/refractory biopsies of 57 patients with PCDLBCL-LT were molecularly characterized with triple FISH and targeted next-generation sequencing for 52 B-cell-lymphoma-relevant genes, including paired analysis in 16 patients. In this cohort, 95% of patients harboured at least one of the three main driver alterations (mutations in MYD88/CD79B and/or CDKN2A-loss). In relapsed/refractory PCDLBCL-LT, these oncogenic aberrations were persistently present, demonstrating genetic stability over time. Novel alterations in relapsed disease affected mostly CDKN2A, MYC, and PIM1. Regarding survival, only MYC rearrangements and HIST1H1E mutations were statistically significantly associated with an inferior outcome. The stable presence of one or more of the three main driver alterations (mutated MYD88/CD79B and/or CDKN2A-loss) is promising for targeted therapies addressing these alterations and serves as a rationale for molecular-based disease monitoring, improving response evaluation and early identification and intervention of disease relapses in these poor-prognostic PCDLBCL-LT patients.

Biological and Clinical Implications of Gene-Expression Profiling in Diffuse Large B-Cell Lymphoma: A Proposal for a Targeted BLYM-777 Consortium Panel as Part of a Multilayered Analytical Approach.

Gene-expression profiling (GEP) is used to study the molecular biology of lymphomas. Here, advancing insights from GEP studies in diffuse large B-cell lymphoma (DLBCL) lymphomagenesis are discussed. GEP studies elucidated subtypes based on cell-of-origin principles and profoundly changed the biological understanding of DLBCL with clinical relevance. Studies integrating GEP and next-generation DNA sequencing defined different molecular subtypes of DLBCL entities originating at specific anatomical localizations. With the emergence of high-throughput technologies, the tumor microenvironment (TME) has been recognized as a critical component in DLBCL pathogenesis. TME studies have characterized so-called "lymphoma microenvironments" and "ecotypes". Despite gained insights, unexplained chemo-refractoriness in DLBCL remains. To further elucidate the complex biology of DLBCL, we propose a novel targeted GEP consortium panel, called BLYM-777. This knowledge-based biology-driven panel includes probes for 777 genes, covering many aspects regarding B-cell lymphomagenesis (f.e., MYC signature, TME, immune surveillance and resistance to CAR T-cell therapy). Regarding lymphomagenesis, upcoming DLBCL studies need to incorporate genomic and transcriptomic approaches with proteomic methods and correlate these multi-omics data with patient characteristics of well-defined and homogeneous cohorts. This multilayered methodology potentially enhances diagnostic classification of DLBCL subtypes, prognostication, and the development of novel targeted therapeutic strategies.

The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: Lymphoid Neoplasms.

We herein present an overview of the upcoming 5th edition of the World Health Organization Classification of Haematolymphoid Tumours focussing on lymphoid neoplasms. Myeloid and histiocytic neoplasms will be presented in a separate accompanying article. Besides listing the entities of the classification, we highlight and explain changes from the revised 4th edition. These include reorganization of entities by a hierarchical system as is adopted throughout the 5th edition of the WHO classification of tumours of all organ systems, modification of nomenclature for some entities, revision of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities, as well as inclusion of tumour-like lesions, mesenchymal lesions specific to lymph node and spleen, and germline predisposition syndromes associated with the lymphoid neoplasms.