SOX11+ Large B-Cell Neoplasms: Cyclin D1-Negative Blastoid/Pleomorphic Mantle Cell Lymphoma or Large B-Cell Lymphoma?

Large or blastoid B-cell neoplasms that are SOX11+ are a diagnostic dilemma and raise a differential diagnosis of cyclin D1-negative blastoid/pleomorphic mantle cell lymphoma (MCL) versus diffuse large B-cell lymphoma (DLBCL) or blastoid high-grade B-cell lymphoma (HGBL) with aberrant SOX11 expression. Here we report a study cohort of 13 SOX11+ large/blastoid B-cell neoplasms. Fluorescence in situ hybridization analysis was negative for CCND1 rearrangement in all 13 cases; 1 of 8 (12.5%) cases tested showed CCND2 rearrangement and 2 (25%) cases had extracopies of CCND2. Gene expression profiling showed that the study group had a gene expression signature similar to cyclin D1+ blastoid/pleomorphic MCL but different from DLBCL. Principal component analysis revealed that the cohort cases overlapped with cyclin D1+ blastoid/pleomorphic MCL but had minimal overlap with DLBCL. All patients in the cohort had clinicopathologic features similar to those reported for patients with cyclin D1+ MCL. We also performed a survey of SOX11 expression in a group of 85 cases of DLBCL and 24 cases of blastoid HGBL. SOX11 expression showed a 100% specificity and positive predictive value for the diagnosis of MCL. Overall, the results support the conclusion that large or blastoid B-cell neoplasms that are positive for SOX11 are best classified as cyclin D1-negative blastoid/pleomorphic MCL, and not as DLBCL or blastoid HGBL. We also conclude that SOX11 is a specific marker for the diagnosis of MCL, including cyclin D1-negative blastoid/pleomorphic MCL cases and should be performed routinely on blastoid/large B-cell neoplasms to help identify potential cases of cyclin D1-negative blastoid/pleomorphic MCL.

Targeted inhibition of DHODH is synergistic with BCL2 blockade in HGBCL with concurrent MYC and BCL2 rearrangement.

High-grade B-cell lymphoma (HGBCL), the subtype of non-Hodgkin lymphoma, to be relapsed or refractory in patients after initial therapy or salvage chemotherapy. Dual dysregulation of MYC and BCL2 is one of the important pathogenic mechanisms. Thus, combined targeting of MYC and BCL2 appears to be a promising strategy. Dihydroorotate dehydrogenase (DHODH) is the fourth rate-limiting enzyme for the de novo biosynthesis of pyrimidine. It has been shown to be a potential therapeutic target for multiple diseases. In this study, the DHODH inhibitor brequinar exhibited growth inhibition, cell cycle blockade, and apoptosis promotion in HGBCL cell lines with MYC and BCL2 rearrangements. The combination of brequinar and BCL2 inhibitors venetoclax had a synergistic inhibitory effect on the survival of DHL cells through different pathways. Venetoclax could upregulate MCL-1 and MYC expression, which has been reported as a resistance mechanism of BCL2 inhibitors. Brequinar downregulated MCL-1 and MYC, which could potentially overcome drug resistance to venetoclax in HGBCL cells. Furthermore, brequinar could downregulate a broad range of genes, including ribosome biosynthesis genes, which might contribute to its anti-tumor effects. In vivo studies demonstrated synergetic tumor growth inhibition in xenograft models with brequinar and venetoclax combination treatment. These results provide preliminary evidence for the rational combination of DHODH and BCL2 blockade in HGBCL with abnormal MYC and BCL2.

The Genetic Profile of Large B-Cell Lymphomas Presenting in the Ocular Adnexa.

To provide insights into targetable oncogenic pathways, this retrospective cohort study investigated the genetic profile of 26 patients with diffuse large B-cell lymphoma, not otherwise specified (DLBCL-NOS), and two patients with high-grade B-cell lymphoma with MYC and BCL2 rearrangements (HGBCL) presenting in the ocular adnexa. Pathogenic variants and copy number variations in 128 B-cell lymphoma-relevant genes were analyzed by targeted next-generation sequencing. Genetic subtypes were determined with the LymphGen algorithm. Primary ocular adnexal DLBCL-NOS constituted 50% (n = 14) and was generally characterized by non-germinal center B-cell origin (non-GCB) (n = 8, 57%), and LymphGen MCD subtype (n = 5, 36%). Primary ocular adnexal DLBCL-NOS presented pathogenic variants in genes involved in NF-κB activation and genes which are recurrently mutated in other extranodal lymphomas of non-GCB origin, including MYD88 (n = 4, 29%), CD79B (n = 3, 21%), PIM1 (n = 3, 21%), and TBL1XR1 (n = 3, 21%). Relapsed DLBCL-NOS presenting in the ocular adnexa (n = 6) were all of non-GCB origin and frequently of MCD subtype (n = 3, 50%), presenting with a similar genetic profile as primary ocular adnexal DLBCL-NOS. These results provide valuable insights into genetic drivers in ocular adnexal DLBCL-NOS, offering potential applications in future precision medicine.

The Clinicopathologic Features and Molecular Signatures of Blastoid High-Grade B Cell Lymphoma, Not Otherwise Specified.

A small subset of high-grade B-cell lymphoma (HGBL) with blastoid morphology remains poorly understood. We assessed 55 cases of blastoid HGBL, not otherwise specified (NOS) and compared their clinicopathologic characteristics with those of 81 non-blastoid HGBL-NOS and 62 blastoid HGBL with MYC and BCL2, with or without BCL6 rearrangements (double/triple-hit lymphoma [D/THL]). Patients with blastoid HGBL-NOS showed similar clinicopathologic features to patients with blastoid D/THLs and non-blastoid HGBL-NOS, except more frequently with a history of low-grade B-cell lymphoma, bone marrow involvement, and BCL2 rearrangement (P < .05) compared to the latter. MYC rearrangement (MYC-R), detected in 40% of blastoid HGBL-NOS, was associated with aggressive clinicopathologic features and poorer overall survival, even worse than that of blastoid D/THL (P < .05). Transcriptome profiling revealed a distinct gene expression pattern with differentially expressed genes enriched in MYC and P53-targeted genes in MYC-R blastoid HGBL-NOS. Fifty-two percent of blastoid HGBL-NOS had a double hit-like signature, similar to non-blastoid HGBL-NOS (P = .73). The overall survival of the blastoid HGBL-NOS group was similar to that of the blastoid D/THL group but appeared poorer than that of its non-blastoid counterparts (P = .07). Taken together, blastoid HGBL-NOS is an aggressive B-cell lymphoma that shares overlapping clinicopathologic and genetic features with non-blastoid HGBL-NOS. MYC-R in patients with blastoid HGBL-NOS identifies a highly aggressive subgroup with distinct aggressive clinicopathologic features, unique molecular signatures, and a dismal clinical outcome.

Lack of reproducibility of histopathological features in MYC-rearranged large B cell lymphoma using digital whole slide images: a study from the Lunenburg lymphoma biomarker consortium.

AIMS: Subclassification of large B cell lymphoma (LBCL) is challenging due to the overlap in histopathological, immunophenotypical and genetic data. In particular, the criteria to separate diffuse large B cell lymphoma (DLBCL) and high-grade B cell lymphoma (HGBL) are difficult to apply in practice. The Lunenburg Lymphoma Biomarker Consortium previously reported a cohort of over 5000 LBCL that included fluorescence in-situ hybridisation (FISH) data. This cohort contained 209 cases with MYC rearrangement that were available for a validation study by a panel of eight expert haematopathologists of how various histopathological features are used. METHODS AND RESULTS: Digital whole slide images of haematoxylin and eosin-stained sections allowed the pathologists to visually score cases independently as well as participate in virtual joint review conferences. Standardised consensus guidelines were formulated for scoring histopathological features and included overall architecture/growth pattern, presence or absence of a starry-sky pattern, cell size, nuclear pleomorphism, nucleolar prominence and a range of cytological characteristics. Despite the use of consensus guidelines, the results show a high degree of discordance among the eight expert pathologists. Approximately 50% of the cases lacked a majority score, and this discordance spanned all six histopathological features. Moreover, none of the histological variables aided in prediction of MYC single versus double/triple-hit or immunoglobulin-partner FISH-based designations or clinical outcome measures. CONCLUSIONS: Our findings indicate that there are no specific conventional morphological parameters that help to subclassify MYC-rearranged LBCL or select cases for FISH analysis, and that incorporation of FISH data is essential for accurate classification and prognostication.

EBV+ high-grade B cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements: a multi-institutional study.

AIMS: It is unknown whether Epstein-Barr virus (EBV) infection can occur in high-grade B cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements, also known as double- or triple-hit lymphoma (DHL/THL). METHODS AND RESULTS: Here we report 16 cases of EBV+ DHL/THL from screening 846 cases of DHL/THL and obtaining additional EBV+ cases through multi-institutional collaboration: eight MYC and BCL2 DHL, six MYC and BCL6 DHL and two THL. There were eight men and eight women, with a median age of 65 years (range = 32-86). Two patients had a history of follicular lymphoma and one had AIDS. Nine of 14 patients had an International Prognostic Index of ≥3. Half of the cases showed high-grade/Burkitt-like morphology and the other half diffuse large B cell lymphoma morphology. Using immunohistochemistry, the lymphoma cells were positive for MYC (n = 14 of 16), BCL2 (n = 12 of 16), BCL6 (n = 14 of 16), CD10 (n = 13 of 16) and MUM1 (n = six of 14). Using Hans' algorithm, 13 cases were classified as germinal centre B cell (GCB) and three as non-GCB. The lymphomas frequently showed an EBV latency Type I with a median EBV-encoded small RNAs of 80% positive cells (range = 20-100%). After a median follow-up of 36.3 months (range = 2.0-41.6), seven patients died, with a median survival of 15.4 months (range = 3.4-47.3) after diagnosis of EBV+ DHL/THL. Five of six patients with MYC and BCL6 DHL were alive, including four in complete remission. In contrast, only four of 10 patients with MYC and BCL2 DHL or THL were alive, including two in complete remission. The median survival in patients with MYC and BCL6 DHL was unreached and was 21.6 months in patients with MYC and BCL2 DHL or THL. CONCLUSIONS: EBV infection in DHL/THL is rare (~1.5%). Cases of EBV+ DHL/THL are largely similar to their EBV- counterparts clinicopathologically. Our findings expand the spectrum of EBV+ B cell lymphomas currently recognised in the World Health Organisation classification and suggest differences between EBV+ MYC and BCL2 DHL versus EBV+MYC and BCL6 DHL that may have therapeutic implications.

Engineered T Cells: CAR T Cell Therapy and Beyond.

PURPOSE OF REVIEW: This article reviews the current data and future directions of engineered T cell therapies in non-Hodgkin lymphomas. RECENT FINDINGS: Currently, four chimeric antigen receptor (CAR) T cell products are approved: axicabtagene ciloleucel, tisagenlecleucel, lisocabtagene maraleucel, and brexucabtagene autoleucel. These products differ in construct, indication, manufacturing, clinical trial design, and toxicity profile, but all are autologous products targeting CD19. Encouraging early data is also emerging with the use of these products in additional subtypes of B cell lymphoma. Alternative engineered T cell products are also in development, including dual CD19/22 targeting CAR T cells, CD30-directed CAR T cells, allogeneic CAR T cells, and engineered natural killer (NK) cells. Preclinical data using novel CAR constructs such as cytokine-secreting CARs targeted gene delivery into the T cell receptor α constant (TRAC) locus, combination strategies, and third-generation CARs holds promise for additional novel approaches. CAR T cells have transformed the therapeutic landscape for patients with relapsed/refractory B cell lymphomas. Early data with novel engineered cellular products is encouraging and holds promise for future clinical use.

AID is a poor prognostic marker of high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements.

Diffuse large B-cell lymphoma with MYC rearrangement is defined as double/triple-hit lymphoma (DHL/THL) or single-hit lymphoma (SHL) by the inclusion of the BCL2 and BCL6 rearrangements status. DHL/THL is called as "high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements" in the World Health Organization 2017 Classification of Tumors of Hematopoietic and Lymphoid Tissues. To find a prognostic biomarker of DHL/THL, we firstly examined 19 cases (molecular analysis series;10 cases of DHL/THL and 9 cases of SHL) with gene expression profile analysis. The gene expression profile analysis showed that the high expression of AICDA was associated with an adverse prognosis in DHL/THL, but not in SHL. Then, we evaluated immunohistochemical expression of AID, the protein product of AICDA, in 50 cases (molecular analysis series of 19 cases and additional immunohistochemistry series of 31 cases; 12 cases of DHL/THL and 19 cases of SHL) and confirmed that its expression was also associated with an adverse prognosis in DHL/THL. Therefore, AICDA and AID can be a predictor of an adverse clinical outcome in DHL/THL and immunohistochemistry of AID is useful to find DHL/THL-adverse prognosis group.

Double-hit and triple-hit high-grade B-cell lymphoma of the ocular adnexa.

High-grade B-cell lymphoma (HGBL) with c-MYC and BCL2 and/or BCL6 rearrangements, also known as a double-hit and triple-hit lymphoma, is an aggressive non-Hodgkin lymphoma affecting older adults. After formal recognition of this entity in the 2017 revision of the World Health Organization Classification of lymphoid neoplasms, only two well-documented cases of triple-hit lymphoma of the orbit appear in the literature. Herein, we describe a 70-year-old man with progressive diplopia, ophthalmoplegia, and rapidly enlarging temporal mass. Biopsy revealed a tumor morphologically consistent with HGBL, coexpressing CD20, CD10, BCL6, BCL2, and c-MYC on immunohistochemical analysis. Fluorescence in-situ hybridization showed rearrangements in c-MYC and BCL-2 genes, confirming double-hit HGBL. Systemic workup revealed Ann Arbor stage IV disease. This report reviews the existing literature on ocular adnexal double-hit and triple-hit lymphoma and provides an update on the diagnostic ancillary studies, prognostic implications, and latest management for this aggressive hematolymphoid malignancy.

A dose-dense short-term therapy for human immunodeficiency virus/acquired immunodeficiency syndrome patients with high-risk Burkitt lymphoma or high-grade B-cell lymphoma: safety and efficacy results of the "CARMEN" phase II trial.

A few prospective trials in HIV-positive patients with Burkitt lymphoma (BL) or high-grade B-cell lymphoma (HGBL) have been reported. Investigated therapies have shown good efficacy but relevant safety problems, with high rates of interruptions, severe mucositis, septic complications, and fungal infections. Here, we report the results of a multicentre phase II trial addressing a new dose-dense, short-term therapy aimed at maintaining efficacy and improving tolerability. The experimental programme included a 36-day polychemotherapy induction followed by high-dose cytarabine-based consolidation and response-tailored BEAM (carmustine, etoposide, cyatarabine, and melphalan)- conditioned autologous stem cell transplantation (ASCT). This therapy would be considered active if ≥11 complete remissions (CR) after induction (primary endpoint) were recorded among 20 assessable patients. HIV-positive adults (median age 42, range 26-58; 16 males) with untreated BL (n = 16), HGBL (n = 3) or double-hit lymphoma (n = 1) were enrolled. All patients had high-risk features, with meningeal and bone marrow infiltration in five and nine patients respectively. The experimental programme was safe and active in a multicentre setting, with only two episodes of grade 4 non-haematological toxicity (hepatotoxicity and mucositis), and no cases of systemic fungal infections; two patients died of toxicity (bacterial infections). Response after induction (median duration: 47 days; interquartile range 41-54), was complete in 13 patients and partial in five [overall response rate = 90%; 95% confidence interval (CI) = 77-100]. All responders received consolidation, and five required autologous stem cell transplant. At a median follow-up of 55 (41-89) months, 14 patients are relapse-free and 15 are alive, with a five-year progression-free survival and an overall survival of 70% (95% CI = 60-80%) and 75% (95% CI = 66-84) respectively. No patient with cerebrospinal fluid (CSF)/meningeal lymphoma experienced central nervous system recurrence. With respect to previously reported regimens, this programme was delivered in a shorter period, and achieved the main goal of maintaining efficacy and improving tolerability.

Patterns of immune checkpoint protein expression in MYC-overexpressing aggressive B-cell non-Hodgkin lymphomas.

Given the poor prognosis of MYC-overexpressing diffuse large B cell lymphoma (DLBCL) and B cell lymphoma unclassifiable with features intermediate between DLBCL and Burkitt lymphoma/high grade B cell lymphoma (BCLU/HGBL), and preclinical data suggesting that MYC may regulate the antitumor immune response, we sought to characterize expression of immune checkpoint proteins on tumor tissue from patients diagnosed with these lymphomas. Immunohistochemical staining for immune checkpoint protein expression was applied to 56 cases of MYC-overexpressing DLBCL and BCLU/HGBL, 35 of which also harbored MYC rearrangement (MYC-R). Analysis revealed both frequent overexpression of immune checkpoint proteins as well as differences in overexpression patterns based upon MYC-R status, with MYC-R cases more likely to overexpress PD-L1 and PD-1 in the tumor microenvironment (50 vs. 15%, p = 0.02 and 32 vs. 5%, p = 0.02, respectively) but less likely to overexpress CTLA-4 and CD80 on tumor cells (34 vs. 71%, p = 0.01 and 34 vs. 81%, p = 0.001, respectively), as compared to cases without MYC-R. These data may suggest a biologic rationale for investigation of the effect of checkpoint inhibitor therapies in these subgroups of MYC-overexpressing DLBCL and BCLU/HGBL.

Molecular classification of aggressive lymphomas-past, present, future.

Aggressive large B-cell lymphomas (LBCLs) represent a frequent but clinically and molecularly heterogeneous group of tumors. Technological advances over the last decades prompted the development of different classification schemas to either sharpen diagnoses, dissect molecular heterogeneity, predict outcome, or identify rational treatment targets. Despite increased diagnostic precision and a noticeably improved molecular understanding of these lymphomas, clinical perspectives of patients largely remain unchanged. Recently, finished comprehensive genomic studies discovered genetically defined LBCL subtypes that predict outcome, provide insight into lymphomagenesis, and suggest rational therapies with the hope of generating patient-tailored treatments with increased perspective for patients in greatest need. Current and future efforts integrate multiomics studies and/or leverage single-cell technologies and will provide us with an even more fine-grained picture of LBCL biology. Here, we highlight examples of how high-throughput technologies aided in a better molecular understanding of LBCLs and provide examples of how to select rationally designed targeted treatment approaches that might personalize LBCL treatment and eventually improve patients' perspective in the near future.

Novel Biological Insights and New Developments in Management of Burkitt Lymphoma and High-Grade B-Cell Lymphoma.

OPINION STATEMENT: Burkitt lymphoma (BL) is highly curable, and prompt institution of therapy is critical to achieving optimal outcomes. Although current "standard" approaches are very effective in disease eradication, treatment-related toxicity makes optimal delivery of curative therapy a challenge, especially in older and immunocompromised individuals. Reduced intensity approaches with fewer toxic complications have been the focus of some recent studies. A critical question is if they can replace "standard" approaches by maintaining high curability with improved tolerability. Additionally, new molecular insights in BL biology suggest that in the future, "targeted therapy" approaches may be feasible using small molecule inhibitors and novel strategies. Recently, a new category of aggressive lymphoma named "high-grade B-cell lymphoma (HGBL) with MYC and BCL2 and/or BCL6 translocations" has been recognized. This category overlaps clinically and biologically with BL and has an inferior prognosis compared to most B-cell lymphomas, and the optimal approach to its management remains, as yet, undefined. In this review, we discuss the current landscape of BL treatment including recent results with low-intensity regimens and also consider current approaches to HGBL. We also explore how recently elucidated novel biological insights in BL biology may shape future therapeutic directions including the use of novel cellular therapy approaches.

Secondary cutaneous involvement by direct extension in high-grade B-cell lymphomas.

Cutaneous involvement by a systemic lymphoma via direct extension is a very rare phenomenon, historically described in patients who had advanced-stage disease with bulky lymphadenopathy. Since its original description, most cases of cutaneous lymphomatous spread via direct extension are attributable to Hodgkin disease. Here, we report the occurrence of direct cutaneous dissemination in the setting of nodal high-grade B-cell lymphomas, specifically diffuse large B-cell lymphoma (DLBCL) and B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and classical Hodgkin lymphoma (also called gray-zone lymphoma). Both cases are adequately documented with clinical, histopathologic, and immunophenotypic data, as well as additional cytogenetic analysis.

Fluorescent nanoparticle-mediated semiquantitative MYC protein expression analysis in morphologically diffuse large B-cell lymphoma.

The current World Health Organization (WHO) classification defines a new disease entity of high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements, making fluorescence in situ hybridization (FISH) screening for these genes mandatory. In addition, the prognostic significance of MYC expression was reported, with a cut-off value of 40%. However, interobserver discrepancies arise due to the heterogeneous intensity of MYC expression by immunohistochemistry. Moreover, a cut-off value of positivity for MYC protein in diffuse large B-cell lymphoma (DLBCL) varies among studies at present. Here, we applied a high-sensitivity semiquantitative immunohistochemical technique using fluorescent nanoparticles called phosphor-integrated dots (PID) to evaluate the MYC expression in 50 de novo DLBCL cases, and compared it with the conventional diaminobenzidine (DAB)-developing system. The high MYC expression detected by the PID-mediated system predicted poor overall survival in DLBCL patients. However, we found no prognostic value of MYC protein expression for any cut-off value by the DAB-developing system, even if the intensity was considered. These results indicate that the precise evaluation of MYC protein expression can clarify the prognostic values in DLBCL, irrespective of MYC rearrangement.

[Genetic evolution of in situ follicular neoplasia to t(14;18)-positive aggressive B-cell lymphoma]. / Die genetische Evolution der in situ follikulären Neoplasie zum t(14;18)-positiven aggressiven B­Zell-Lymphom.

BACKGROUND: In situ follicular neoplasia (ISFN) is a t(14;18)(q32;q21)+ precursor lesion of follicular lymphoma (FL), which in turn can transform into diffuse large B­cell lymphoma (DLBCL). For DLBCL that arise de novo, no precursor lesion is known. Given the high frequency of the t(14;18) translocation in de novo DLBCL as well, we investigated whether they can also arise from ISFN without FL as an intermediate step. OBJECTIVES: To investigate the clonal evolution of ISFN to DLBCL - transformed from FL and de novo. MATERIALS AND METHODS: Identification of ISFN lesions in patients with DLBCL was performed by BCL2 staining of reactive lymphoid tissues. ISFN and DLBCL were subsequently analyzed by fluorescence in situ hybridization, clonality analyses, sequencing of the t(14;18) breakpoint, and targeted next-generation sequencing. RESULTS: 10 cases with paired ISFN and DLBCL samples were identified, 6 of which were de novo DLBCL and 4 transformed from FL. 3 DLBCL carried MYC-rearrangements in addition to the t(14;18) and were classified as high-grade B­cell lymphoma (HGBL). The clonal relationship of ISFN and DLBCL/HGBL was confirmed for all cases. CREBBP, KMT2D, EZH2, TNFRSF14, and BCL2 were the genes most frequently mutated, with the distribution of private and shared mutations pointing to 2 different scenarios of clonal evolution. In most cases, DLBCL/HGBL, ISFN, and, if also present, FL had evolved divergently from a common progenitor, whereas linear evolution was less frequent. CONCLUSION: We show for the first time that t(14;18)+ DLBCL/HGBL can arise directly from ISFN without FL as an intermediate step and that during this progression, divergent evolution is common.

[Molecular classification of aggressive B-cell lymphoma].

Diffuse large B-cell lymphoma (DLBCL) is a clinically and biologically highly heterogeneous disease; various molecular genetic abnormalities contribute to DLBCL development. In particular, recent advances in genomics technologies have led to the discovery of unknown genetic abnormalities and gene expression patterns. Based on the identified pathophysiologies, molecular sub-classification of DLBCL has been progressing. These are important for the discovery of new therapeutic agents and the planning of clinical trials and should be recognized by clinicians as the basis of future personalized medicine.

Pitfalls in mononucleotide microsatellite repeats instability assessing (MSI) in the patients with B-cell lymphomas.

Analysis of microsatellite instability (MSI) is a routine study in the diagnostics of solid malignancies. The standard for determining MSI is a pentaplex PCR panel of mononucleotide repeats: NR-21, NR-24, NR-27, BAT-25, BAT-26. The presence of MSI is established based on differences in the length of markers in the tumor tissue and in the control, but due to the quasimonomorphic nature of standard mononucleotide loci the use of a control sample is not necessary in the diagnosis of MSI-positive solid tumors. The significance of the MSI phenomenon in oncohematology has not been established. This paper presents the results of a study of MSI in B-cell lymphomas: follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), high-grade B-cell lymphoma (HGBL). We have shown that aberrations of mononucleotide markers occur in these diseases, but the nature of the changes does not correspond to the classical MSI in solid neoplasms. This fact requires further study of the pathogenesis of such genetic disorders. Due to the possibility of ambiguous interpretation of the results of the MSI study for previously uncharacterized diseases, strict compliance with the methodology of parallel analysis of the tumor tissue and the control sample is mandatory.

Abemaciclib, a CDK4/6 inhibitor, exerts preclinical activity against aggressive germinal center-derived B-cell lymphomas.

The revised WHO classification newly defined the entities "High-grade B-cell lymphoma with MYC and BCL2, and/or BCL6 rearrangements (HGBL-DH/TH)" and "HGBL, NOS." Standard immunochemotherapy for diffuse large B-cell lymphoma (DLBCL), R-CHOP, is insufficient for HGBL patients, and there are currently no optimized therapeutic regimens for HGBL. We previously reported that CCND3, which encodes cyclin D3, harbored high mutation rates in Burkitt lymphoma (BL), HGBL and a subset of DLBCL. Furthermore, the knockdown of cyclin D3 expression was toxic to germinal center (GC)-derived B-cell lymphomas. Thus, the fundamental function of cyclin D3 is important for the pathogenesis of GC-derived B-cell lymphoma. We herein used two structurally different CDK4/6 inhibitors, palbociclib and abemaciclib, and examined their suppressive effects on cell proliferation and their ability to induce apoptosis in various aggressive B-cell lymphoma cell lines. The results obtained demonstrated that abemaciclib more strongly suppressed cell proliferation and induced apoptosis in GC-derived B-cell lymphoma cell lines than the control, but only slightly inhibited those features in activated B-cell (ABC)-like DLBCL cell lines. Palbociclib exerted partial or incomplete effects compared with the control and the effect was intermediate between abemaciclib and the control. Moreover, the effects of abemaciclib appeared to depend on cyclin D3 expression levels based on the results of the expression analysis of primary aggressive B-cell lymphoma samples. Therefore, abemaciclib has potential as a therapeutic agent for aggressive GC-derived B-cell lymphomas.

Outcomes in patients with aggressive B-cell non-Hodgkin lymphoma after intensive frontline treatment failure.

BACKGROUND: Salvage immunochemotherapy followed by high-dose chemotherapy and autologous stem cell transplantation is the standard-of-care second-line treatment for patients with relapsed/refractory diffuse large B-cell lymphoma after first-line R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone). Outcomes after receipt of second-line immunochemotherapy in patients with aggressive B-cell lymphomas who relapse or are refractory to intensive first-line immunochemotherapy regimens (etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab [R-EPOCH], rituximab, hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone alternating with methotrexate and cytarabine [R-HyperCVAD], rituximab, cyclophosphamide, vincristine, doxorubicin, and high-dose methotrexate alternating with ifosfamide, etoposide, and cytarabine [R-CODOX-M/IVAC]) remain unknown. METHODS: Outcomes of patients with non-Burkitt, aggressive B-cell lymphomas and relapsed/refractory disease after first-line treatment with intensive immunochemotherapy regimens who received platinum-based second-line immunochemotherapy were reviewed retrospectively. Analyses were performed to determine progression-free survival (PFS) and overall survival (OS) from the time of receipt of second-line immunochemotherapy. RESULTS: In total, 195 patients from 19 academic centers were included in the study. The overall response rate to second-line immunochemotherapy was 44%, with a median PFS of 3 months and a median OS of 8 months. Patients with early treatment failure (primary refractory or relapse <12 months from completion of first-line therapy) experienced inferior median PFS (2.8 vs 23 months; P < .001) and OS (6 months vs not reached; P < .001) compared with patients with late treatment failure. Although the 17% of patients with early failure who achieved a complete response to second-line immunochemotherapy experienced prolonged survival, this outcome could not be predicted by clinicopathologic features at the start of second-line immunochemotherapy. CONCLUSIONS: Patients with early treatment failure after intensive first-line immunochemotherapy experience poor outcomes after receiving standard second-line immunochemotherapy. The use of standard-of-care or experimental therapies currently available in the third-line setting and beyond should be investigated in the second-line setting for these patients.