Genomic alterations and gene expression in primary diffuse large B-cell lymphomas of immune-privileged sites: the importance of apoptosis and immunomodulatory pathways

Comparison of differences in transcriptional and genetic profiles between intra-central nervous system and extra-central nervous system large B-cell lymphoma

Primary central nervous system diffused large B-cell lymphoma (PCNS-DLBCL) is a rare type of non-Hodgkin lymphoma restricted to the central nervous system (CNS). To explore its specific pathogenesis and therapeutic targets, we performed multi-omics sequencing on tumor samples from patients diagnosed with PCNS-DLBCL, secondary CNS-DLBCL or extracranial (ec) DLBCL.By single-cell RNA sequencing, highly proliferated and dark zone (DZ)-related B cell subclusters, MKI67_B1, PTTG1_B2 and BTG1_B3, were predominant significantly in PCNS-DLBCL. Compared to SCNS-DLBCL and ecDLBCL, an immune-suppressive tumor microenvironment was observed in PCNS-DLBCL by analysis of immune-stimulating/inhibitory ligand‒receptor (L-R) pairs. By performing whole-exome sequencing in 93 patients, mutations enriched in BCR-NFkB and TLR pathways and the cooperation of these two pathways were found to be predominant in PCNS-DLBCL comparing to nonGCB-ecDLBCL. In summary, our study provides comprehensive insights into the transcriptomic and genetic characteristics of PCNS-DLBCL in contrast to ecDLBCL and will help dissect the oncogenic mechanism of this disease.

Genomic landscape and distinct molecular subtypes of primary testicular lymphoma

Primary testicular lymphoma (PTL) is a rare lymphoma predominantly occurring in the elderly male population. It is characterized by a limited response to treatment and a heightened tendency towards relapse. Histologically, approximately 90% of PTL cases are classified as diffuse large B-cell lymphomas (DLBCL). Genetic features of PTL were delineated in a limited scope within several independent studies. Some of the articles which analyzed the genetic characterization of DLBCL have incorporated PTL samples, but these have been constrained by small sample sizes. In addition, there have been an absence of independent molecular typing studies of PTL. This report summarizes the common mutational features, copy number variations (CNVs) and molecular typing of PTL patients, based on whole-exome sequencing (WES) conducted on a cohort of 25 PTL patients. Among them, HLA, CDKN2A and MYD88 had a high mutation frequency. In addition, we found two core mutational characteristics in PTL including mutation in genes linked to genomic instability (TP53 and CDKN2A) and mutation in immune-related genes (HLA, MYD88, CD79B). We performed molecular typing of 25 PTL patients into C1 subtype with predominantly TP53 mutations and C2 subtype with predominantly HLA mutations. Notably, mutations in the TP53 gene predicted a poor outcome in most types of lymphomas. However, the C1 subtype, dominated by TP53 mutations, had a better prognosis compared to the C2 subtype in PTL. C2 subtype exhibited a worse prognosis, aligning with our finding that the mechanism of immune escape in PTL was primarily the deletions of HLA rather than PD-L1/PD-L2 alterations, a contrast to other DLBCLs. Moreover, we calculated the tumor mutation burden (TMB) and identified that TMB can predict prognosis and recurrence rate in PTL. Our study underscores the significance of molecular typing in PTL based on mutational characteristics, which plays a crucial role in prognostication and guiding therapeutic strategies for patients.

Diagnostic, Pathologic, and Therapeutic Considerations for Primary CNS Lymphoma

Primary CNS lymphoma (PCNSL) is a rare lymphoma representing 3% of CNS malignancies. The diagnosis is complicated by the unique risks associated with brain biopsy, and the treatment is similarly complicated by the restriction of effective therapeutics able to cross the blood-brain barrier. Currently, the majority of individuals diagnosed with this disease are immunocompetent although immune deficiency related to HIV or immunosuppressive therapy remains an important risk factor. Improvements in both frontline therapy and consolidation options, including the use of hematopoietic stem-cell transplantation, have translated to improved survival. Unfortunately, patients experiencing relapsed or refractory disease often fare poorly. Here, we review key clinical, pathologic, and therapeutic aspects of PCNSL and highlight challenging clinical scenarios that may be encountered by the treating oncologist.

Analysis of the genomic landscape of primary central nervous system lymphoma using whole-genome sequencing in Chinese patients

Primary central nervous system lymphoma (PCNSL) is an uncommon non-Hodgkin's lymphoma with poor prognosis. This study aimed to depict the genetic landscape of Chinese PCNSLs. Whole-genome sequencing was performed on 68 newly diagnosed Chinese PCNSL samples, whose genomic characteristics and clinicopathologic features were also analyzed. Structural variations were identified in all patients with a mean of 349, which did not significantly influence prognosis. Copy loss occurred in all samples, while gains were detected in 77.9% of the samples. The high level of copy number variations was significantly associated with poor progression-free survival (PFS) and overall survival (OS). A total of 263 genes mutated in coding regions were identified, including 6 newly discovered genes (ROBO2, KMT2C, CXCR4, MYOM2, BCLAF1, and NRXN3) detected in ⩾ 10% of the cases. CD79B mutation was significantly associated with lower PFS, TMSB4X mutation and high expression of TMSB4X protein was associated with lower OS. A prognostic risk scoring system was also established for PCNSL, which included Karnofsky performance status and six mutated genes (BRD4, EBF1, BTG1, CCND3, STAG2, and TMSB4X). Collectively, this study comprehensively reveals the genomic landscape of newly diagnosed Chinese PCNSLs, thereby enriching the present understanding of the genetic mechanisms of PCNSL.

Primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a diffuse large B cell lymphoma in which the brain, spinal cord, leptomeninges and/or eyes are exclusive sites of disease. Pathophysiology is incompletely understood, although a central role seems to comprise immunoglobulins binding to self-proteins expressed in the central nervous system (CNS) and alterations of genes involved in B cell receptor, Toll-like receptor and NF-κB signalling. Other factors such as T cells, macrophages or microglia, endothelial cells, chemokines, and interleukins, probably also have important roles. Clinical presentation varies depending on the involved regions of the CNS. Standard of care includes methotrexate-based polychemotherapy followed by age-tailored thiotepa-based conditioned autologous stem cell transplantation and, in patients unsuitable for such treatment, consolidation with whole-brain radiotherapy or single-drug maintenance. Personalized treatment, primary radiotherapy and only supportive care should be considered in unfit, frail patients. Despite available treatments, 15-25% of patients do not respond to chemotherapy and 25-50% relapse after initial response. Relapse rates are higher in older patients, although the prognosis of patients experiencing relapse is poor independent of age. Further research is needed to identify diagnostic biomarkers, treatments with higher efficacy and less neurotoxicity, strategies to improve the penetration of drugs into the CNS, and roles of other therapies such as immunotherapies and adoptive cell therapies.

AMD3100-mediated CXCR4 inhibition impairs development of primary lymphoma of the central nervous system

A hallmark of primary lymphoma of the central nervous system (PCNSL, CNS) is the strong CXCR4 expression of the tumor cells, the function of which is still unknown. In vitro treatment of BAL17^CNS lymphoma cells by AMD3100 which inhibits CXCR4-CXCL12 interactions resulted in the significantly differential expression of 273 genes encoding proteins involved in cell motility, cell-cell signaling and interaction, hematological system development and function, and immunological disease. Among the genes downregulated was the one encoding CD200, a regulator of CNS immunological activity. These data directly translated into the in vivo situation; BAL17^CNS CD200 expression was downregulated by 89% (3% vs. 28% CD200+ lymphoma cells) in AMD3100-treated vs. untreated mice with BAL17^CNS-induced PCNSL. Reduced lymphoma cell CD200 expression may contribute to the markedly increased microglial activation in AMD3100-treated mice. AMD3100 also maintained the structural integrity of blood-brain barrier tight junctions and the outer basal lamina of cerebral blood vessels. Subsequently, lymphoma cell invasion of the brain parenchyma was impaired and maximal parenchymal tumor size was significantly reduced by 82% in the induction phase. Thus, AMD3100 qualified as potentially attractive candidate to be included into the therapeutic concept of PCNSL. Beyond therapy, CXCR4-induced suppression of microglial activity is of general neuroimmunological interest and identifies CD200 expressed by the lymphoma cells as a novel mechanism of immune escape in PCNSL.

Whole-Genome/Exome Sequencing Uncovers Mutations and Copy Number Variations in Primary Diffuse Large B-Cell Lymphoma of the Central Nervous System

Background/objective: Identification of key genetic alterations is of importance in the targeted therapies of primary central nervous system lymphoma (PCNSL). However, only a small number of studies have been carried out in PCNSL. In this study, we further described the genetic mutations and copy number variations (CNVs) in PCNSL patients using whole-genome/exome sequencing (WGS/WES), as well as revealed their associations with patients’ clinicopathological features and prognosis.

Methods: Tumor specimens from 38 patients with primary diffuse large B-cell lymphoma of the central nervous system (CNS DLBCL) were enrolled to WGS (n = 24) or WES (n = 14). The CNVs and mutations of 24 samples (WGS) and 38 samples (WGS/WES) were characterized, respectively. The associations between CNVs and mutations with the overall survival rates of PCNSL patients were also evaluated.

Results: The most common mutations were identified in IGLL5 (68%), PIM1 (63%), MYD88 (55%), CD79B (42%), BTG2 (39%), PCLO (39%), KMT2D (34%), and BTG1 (29%) genes. Among the mutated genes, EP300, ETV6, and HIST1H1E mutations were exclusively detected in the elderly, while DUSP2 mutations were associated with the immune microenvironment indicators. In addition, KMT2D mutation was associated with a poor prognosis. In addition, 488 CNVs including 91 gains and 397 deletions were observed across 24 samples from WGS results. Notably, 1q31.3 amplification was closely associated with the poor prognosis of PCNSL patients.

Conclusion: This study further characterizes the genomic landscape of primary CNS DLBCL using WGS/WES, which provides insight into understanding the pathogenesis of PCNSL and fosters new ideas for the targeted treatment of PCNSL.

Impact of a Faulty Germinal Center Reaction on the Pathogenesis of Primary Diffuse Large B Cell Lymphoma of the Central Nervous System

Simple Summary

The pathogenetic mechanisms and peculiar tropism of primary CNS lymphoma (PCNSL) of the central nervous system (CNS) have been the subject of debate for decades. Hypothesis-driven targeted molecular studies have revealed that PCNSLs derived from self-/polyreactive B cells that have escaped developmental control mechanisms. The early acquisition of activating mutations targeting the B cell receptor pathway provides a survival advantage. The failure of the germinal center (GC) reaction and its checkpoints increases tumor B cell affinity for the CNS. During this faulty GC reaction, PCNSL tumor cells acquire further oncogenic alterations converging on the Toll-like receptor, B cell receptor, and NF-κB pathway. These activated pathways sustain proliferation. Concomitantly, cells become unable to complete terminal B cell differentiation, becoming trapped within the vicious cycle of the GC reaction as low-affinity IgM+ B cells related to memory cells.

Abstract

Primary lymphoma of the central nervous system (PCNSL, CNS) is a specific diffuse large B cell lymphoma (DLBCL) entity confined to the CNS. Key to its pathogenesis is a failure of B cell differentiation and a lack of appropriate control at differentiation stages before entrance and within the germinal center (GC). Self-/polyreactive B cells rescued from apoptosis by MYD88 and/or CD79B mutations accumulate a high load of somatic mutations in their rearranged immunoglobulin (IG) genes, with ongoing somatic hypermutation (SHM). Furthermore, the targeting of oncogenes by aberrant SHM (e.g., PIM1, PAX5, RHOH, MYC, BTG2, KLHL14, SUSD2), translocations of the IG and BCL6 genes, and genomic instability (e.g., gains of 18q21; losses of 9p21, 8q12, 6q21) occur in these cells in the course of their malignant transformation. Activated Toll-like receptor, B cell receptor (BCR), and NF-κB signaling pathways foster lymphoma cell proliferation. Hence, tumor cells are arrested in a late B cell differentiation stage, corresponding to late GC exit B cells, which are genetically related to IgM+ memory cells. Paradoxically, the GC reaction increases self-/polyreactivity, yielding increased tumor BCR reactivity for multiple CNS proteins, which likely contributes to CNS tropism of the lymphoma. The loss of MHC class I antigen expression supports tumor cell immune escape. Thus, specific and unique interactions of the tumor cells with resident CNS cells determine the hallmarks of PCNSL.

Update on Novel Therapeutics for Primary CNS Lymphoma

Simple Summary

Primary central nervous system lymphoma is a rare and aggressive form of non-Hodgkin lymphoma. While it is highly responsive to first-line chemo and radiation treatments, rates of relapse are high, demonstrating the need for improved therapeutic strategies. Recent advancements in the understanding of the pathophysiology of this disease have led to the identification of new potential treatment targets and the development of novel agents. This review aims to discuss different targeted strategies and review some of the data supporting these approaches, and discusses recently completed and ongoing clinical trials using these novel agents.

Abstract

Primary central nervous system lymphoma (PCNSL) is a rare lymphoma isolated to the central nervous system or vitreoretinal space. Standard treatment consists of cytotoxic methotrexate-based chemotherapy, with or without radiation. Despite high rates of response, relapse is common, highlighting the need for novel therapeutic approaches. Recent advances in the understanding of PCNSL have elucidated mechanisms of pathogenesis and resistance including activation of the B-cell receptor and mammalian target of rapamycin pathways. Novel treatment strategies such as the Bruton’s tyrosine kinase (BTK) inhibitor ibrutinib, phosphatidylinositol-3 kinase (PI3K) inhibitors, and immunomodulatory drugs are promising. Increasingly, evidence suggests immune evasion plays a role in PCNSL pathogenesis and several immunotherapeutic strategies including checkpoint inhibition and targeted chimeric antigen receptor T (CAR-T) cells are under investigation. This review provides a discussion on the challenges in development of targeted therapeutic strategies, an update on recent treatment advances, and offers a look toward ongoing clinical studies.

Disseminated soft tissue diffuse large B-cell lymphoma involving multiple abdominal wall muscles: A case report

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma, and patients with DLBCL typically present rapidly growing masses. Lymphoma involving muscle is rare and accounts for only 5%; furthermore, multiple muscles and soft tissue involvement of DLBCL is unusual. Due to unusual clinical manifestation, accurate diagnosis could be delayed.

CASE SUMMARY

A 61-year-old man complained of swelling, pain and erythematous changes in the lower abdomen. Initially, soft tissue infection was suspected, however, skin lesion did not respond to antibiotics. ¹⁸Fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography-computed tomography demonstrated FDG uptake not only in the skin and subcutaneous tissue of the abdomen but also in the abdominal wall muscles, peritoneum, perineum, penis and testis. DLBCL was confirmed by biopsy of the abdominal wall muscle and subcutaneous tissue. After intensive treatment including chemotherapy with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone, central nervous system prophylaxis (intrathecal injection of methotrexate, cytarabine and hydrocortisone) and orchiectomy, he underwent peripheral blood stem cell mobilization for an autologous hematopoietic stem cell transplantation. Despite intensive treatment, the disease progressed rapidly and the patient showed poor outcome (overall survival, 9 mo; disease free survival, 3 mo).

CONCLUSION

The first clinical manifestation of soft tissue DLBCL involving multiple muscles was similar to the infection of the soft tissue.

Testicular Diffuse Large B-Cell Lymphoma-Clinical, Molecular, and Immunological Features

Simple Summary

Testicular diffuse large B-cell lymphoma (T-DLBCL) is a rare and aggressive lymphoma entity that mainly affects elderly men. It has a high relapse rate with especially the relapses of the central nervous system associating with dismal outcome. T-DLBCL has a unique biology with distinct genetic characteristics and clinical presentation, and the increasing knowledge on the tumor microenvironment of T-DLBCL highlights the significance of the host immunity and immune escape in this rare lymphoma, presenting in an immune-privileged site of the testis. This review provides an update on the latest progress made in T-DLBCL research and summarizes the clinical perspectives in T-DLBCL.

Abstract

Primary testicular lymphoma is a rare lymphoma entity, yet it is the most common testicular malignancy among elderly men. The majority of the cases represent non-germinal center B-cell-like (non-GCB) diffuse large B-cell lymphoma (DLBCL) with aggressive clinical behavior and a relatively high relapse rate. Due to the rareness of the disease, no randomized clinical trials have been conducted and the currently recognized standard of care is based on retrospective analyses and few phase II trials. During recent years, the tumor microenvironment (TME) and tumor-related immunity have been the focus of many tumor biology studies, and the emergence of targeted therapies and checkpoint inhibitors has significantly modulated the field of cancer therapies. Testicular DLBCL (T-DLBCL) is presented in an immune-privileged site of the testis, and the roles of NF-κB pathway signaling, 9p24.1 aberrations, and tumor-infiltrating immune cells, especially immune checkpoint expressing lymphocytes and macrophages, seem to be unique compared to other lymphoma entities. Preliminary data on the use of immune checkpoint inhibitors in the treatment of T-DLBCL are promising and more studies are ongoing.

A case at crossroads-urological presentation, cardiac complication and haematological diagnosis: should imaging be pursued prior to orchidectomy at all costs?

This case report explores the interesting case of a 71-year-old gentleman who presented with a testicular lump following trauma. Ultrasound imaging of the testicle demonstrated malignancy and subsequently orchidectomy was listed. Due to a scheduling difficulty, this was prioritized ahead of his whole-body computed tomography scan. Intraoperatively, he developed electrocardiogram changes suggestive of a non-ST elevated myocardial infarction. Post-operative imaging demonstrated a diffuse large B-cell lymphoma encroaching the heart and greater vessels. This case report highlights the importance of preoperative imaging, even where it may prove challenging. We assess the adequacy of current guidelines within the UK on imaging for new testicular malignancies.

Central Nervous System Lymphoma: Approach to Diagnosis and Treatment

Central nervous system lymphoma (CNSL) is a rare form of extranodal non-Hodgkin lymphoma. Central nervous system lymphoma can be primary (isolated to the central nervous space) or secondary in the setting of systemic disease. Treatment of CNSL has improved since the introduction of high-dose methotrexate and aggressive consolidation regimens. However, results after treatment are durable in only half of patients, and long-term survivors may experience late neurotoxicity, impacting quality of life. Given the rarity of this disease, few randomized prospective trials exist. This leaves many questions unanswered regarding optimal first-line and salvage treatments. Recent advances in the knowledge of pathophysiology of CNSL will hopefully help the development of future treatments. This review gives an overview of the epidemiology, pathophysiology, clinical presentation, diagnosis, and treatment of immunocompetent patients with CNSL.

Testis-Specific Thioredoxins TXNDC2, TXNDC3, and TXNDC6 Are Expressed in Both Testicular and Systemic DLBCL and Correlate with Clinical Disease Presentation

DLBCL is the most common type of non-Hodgkin lymphoma with a substantial group of patients suffering a poor prognosis. Therefore more specific markers are required for better understanding of disease biology and treatment. This study demonstrates that testis-specific antioxidant enzymes TXNDC2, TXNDC3, and TXNDC6 alongside oxidative stress marker 8-OHdG are expressed in both testicular and systemic DLBCL, and their presence or absence has correlations with clinical risk factors such as the number of extranodal effusion, the appearance of B-symptoms, and treatment response. Biopsy samples were collected from 28 systemic and 21 testicular male DLBCL patients. The samples were histostained with TXNDC2, TXNDC3, TXNDC6, and 8-OHdG, then graded by a hematopathologist blinded to clinical data. Immunoelectron microscopy was used as a second method to confirm the reliability of the acquired immunohistochemistry data. The absence of nuclear TXNDC2 expression in testicular DLBCL cells correlated with worse primary treatment response, cytoplasmic TXNDC3 expression in testicular and systemic DLBCL associated with lower frequency of B-symptoms, and TXNDC6 expression in cytoplasm in systemic DLBCL had a clinical significance with higher LD levels suggesting a role in the biological nature of these lymphomas. Overall, TXNDC3 cytoplasmic expression is correlated with a more positive outcome in both testicular and systemic DLBCL, while TXNDC6 cytoplasmic expression is associated with a negative outcome in systemic DLBCL.

The immune contexture of primary central nervous system diffuse large B cell lymphoma associates with patient survival and specific cell signaling

Rationale: Primary central nervous system diffuse large B-cell lymphoma (PCNSL) is a rare and aggressive entity that resides in an immune-privileged site. The tumor microenvironment (TME) and the disruption of the immune surveillance influence lymphoma pathogenesis and immunotherapy resistance. Despite growing knowledge on heterogeneous therapeutic responses, no comprehensive description of the PCNSL TME is available. We hence investigated the immune subtypes of PCNSL and their association with molecular signaling and survival. Methods: Analysis of PCNSL transcriptomes (sequencing, n = 20; microarrays, n = 34). Integrated correlation analysis and signaling pathway topology enabled us to infer intercellular interactions. Immunohistopathology and digital imaging were used to validate bioinformatic results. Results: Transcriptomics revealed three immune subtypes: immune-rich, poor, and intermediate. The immune-rich subtype was associated to better survival and characterized by hyper-activation of STAT3 signaling and inflammatory signaling, e.g., IFNγ and TNF-α, resembling the hot subtype described in primary testicular lymphoma and solid cancer. WNT/β-catenin, HIPPO, and NOTCH signaling were hyper-activated in the immune-poor subtype. HLA down-modulation was clearly associated with a low or intermediate immune infiltration and the absence of T-cell activation. Moreover, HLA class I down-regulation was also correlated with worse survival with implications on immune-intermediate PCNSL that frequently feature reduced HLA expression. A ligand-receptor intercellular network revealed high expression of two immune checkpoints, i.e., CTLA-4/CD86 and TIM-3/LAGLS9. TIM-3 and galectin-9 proteins were clearly upregulated in PCNSL. Conclusion: Altogether, our study reveals that patient stratification according to immune subtypes, HLA status, and immune checkpoint molecule quantification should be considered prior to immune checkpoint inhibitor therapy. Moreover, TIM-3 protein should be considered an axis for future therapeutic development.

DNA Copy Number Changes in Diffuse Large B Cell Lymphomas

Copy number aberrations (CNV/CNA) represent a major contribution to the somatic mutation landscapes in cancers, and their identification can lead to the discovery of oncogenetic targets as well as improved disease (sub-) classification. Diffuse large B cell lymphoma (DLBCL) is the most common lymphoma in Western Countries and up to 40% of the affected individuals still succumb to the disease. DLBCL is an heterogenous group of disorders, and we call DLBCL today is not necessarily the same disease of a few years ago. This review focuses on types and frequencies of regional DNA CNVs in DLBCL, not otherwise specified, and in two particular conditions, the transformation from indolent lymphomas and the DLBCL in individuals with immunodeficiency.

The immune landscape and response to immune checkpoint blockade therapy in lymphoma

The clinical development of effective cancer immunotherapies, along with advances in genomic analysis, has led to the identification of tumor environmental features that predict for sensitivity to immune checkpoint blockade therapy (CBT). Early-phase clinical trial results have demonstrated the remarkable effectiveness of CBT in specific lymphoma subtypes, including classical Hodgkin lymphoma and primary mediastinal B-cell lymphoma. Conversely, CBT has been relatively disappointing in follicular lymphoma and diffuse large B-cell lymphoma. These clinical observations, coupled with important scientific discoveries, have uncovered salient features of the lymphoma microenvironment that correlate with immunotherapy response in patients. For example, classical Hodgkin lymphoma is characterized by an inflammatory environment, genetic alterations that facilitate escape from immune attack, and sensitivity to PD-1 blockade therapy. On the other hand, for lymphomas in which measures of immune surveillance are lacking, including follicular lymphoma and most diffuse large B-cell lymphomas, anti-PD-1 therapy has been less effective. An improved understanding of the immune landscapes of these lymphomas is needed to define subsets that might benefit from CBT. In this article, we describe the immune environments associated with major B-cell lymphomas with an emphasis on the immune escape pathways orchestrated by these diseases. We also discuss how oncogenic alterations in lymphoma cells may affect the cellular composition of the immune environment and ultimately, vulnerability to CBT. Finally, we highlight key areas for future investigation, including the need for the development of biomarkers that predict for sensitivity to CBT in lymphoma patients.

Mutational dynamics and immune evasion in diffuse large B-cell lymphoma explored in a relapse-enriched patient series

Diagnostic and relapse diffuse large B-cell lymphoma (DLBCL) biopsies reveal increased mutational burden/loss of heterozygosity in HLA-A . Serially sampled tumor biopsies provide insight into therapeutic targets and evolutionary divergence in relapsed/refractory DLBCL.

Comprehensive approach to diagnosis and treatment of newly diagnosed primary CNS lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare form of non-Hodgkin lymphoma that affects the brain parenchyma, spinal cord, eyes, and cerebrospinal fluid without evidence of systemic, non-CNS involvement. PCNSL is uncommon and only a few randomized trials have been completed in the first-line setting. Over the past decades, the prognosis of PCNSL has improved, mainly due to the introduction and widespread use of high-dose methotrexate, which is now the backbone of all first-line treatment polychemotherapy regimens. Despite this progress, durable remission is recorded in only 50% of patients, and therapy can be associated with significant late neurotoxicity. Here, we overview the epidemiology, clinical presentation, staging evaluation, prognosis, and current up-to-date treatment of immunocompetent PCNSL patients.

Primary Intra-Axial Diffuse Large B-Cell Lymphoma in Immunocompetent Patients: Clinical Impact of Molecular Analysis and Histogenetic Evaluation

Primary central nervous system (CNS) diffuse large B-cell lymphoma (DLBCL) represents less than 1% of non-Hodgkin lymphomas and 2%-3% of brain tumors. Primary CNS DLBCL occurs sporadically in healthy patients. Tumor development and progression have been associated with reduced/absent expression of human leukocyte antigen class I and II proteins; increased expression of CXCR4, CXCL12, CXCR5, and CCR7; mutations of VH4/34, BCL6, MYC, and PAX5 genes; and rearrangement of immunoglobulin heavy and light chain genes. Generally, DLBCL is a single supratentorial lesion (60%-70%), and stereotactic biopsy and intraoperative examination are the main diagnostic methods. Distinctive histologic features are a diffuse growth pattern and angioinvasiveness. Most neoplastic cells resemble centroblasts and exhibit positive CD20, CD22, PAX5, CD79a, and MUM1 expression. The prognosis of primary CNS DLBCL is less favorable than that of nodal DLBCL, and DLBCL subtype, strong FOXP1 immunoreactivity, MYC and BCL2 overexpression, and BCL6 translocations are associated with poor prognosis.

Introduction of novel agents in the treatment of primary CNS lymphoma

Novel insights into the pathophysiology of primary central nervous system lymphoma (PCNSL) have identified the B-cell receptor and Toll-like receptor pathway as well as immune evasion and suppressed tumor immune microenvironment as a key mechanism in the pathogenesis of PCNSL. Small molecules and novel agents targeting these aberrant pathways have been introduced into clinical trials targeting the recurrent or refractory PCNSL patient population. Agents like the Bruton tyrosine kinase (BTK) inhibitor ibrutinib or immunomodulatory drugs (IMiDs) like pomalidomide and lenalidomide have shown promising high response rates in the salvage setting. Here, we give an overview about the recent, exciting developments in PCNSL and summarize the results of clinical trials using novel agents in the recurrent and refractory salvage setting, which include immune checkpoint inhibitors, IMiDs, as well as BTK, phosphatidylinositol-3 kinase, and mammalian target of rapamycin inhibitors.

The survival and prognostic factors of primary testicular lymphoma: two-decade single-center experience

This study aims to investigate the effect of different local testicular treatments and validate common prognostic factors on primary testicular lymphoma (PTL) patients. We retrospectively reviewed the clinical records of 32 patients from 1993 to 2017 diagnosed with PTL and included 22 patients for analysis. The Kaplan-Meier method, Log-rank test, and multivariate Cox proportional hazard regression analysis were applied to evaluate progression-free survival (PFS), overall survival (OS), and determine prognosis predictors. The median follow-up time was 30 months. Median OS and PFS were 96 months and 49 months, respectively. In univariate analysis, advanced Ann Arbor stage (III/IV) (P < 0.001), B symptoms (P < 0.001), and extranodal involvement other than testis (P = 0.001) were significantly associated with shorter OS and PFS. In multivariate analysis, Ann Arbor stage was significantly associated with OS (OR = 11.58, P = 0.049), whereas B symptom was significantly associated with PFS (OR = 11.79, P= 0.049). In the 10 patients with the systemic usage of rituximab, bilateral intervention could improve median OS from 16 to 96 months (P = 0.032). The study provides preliminary evidence on bilateral intervention in testes in the rituximab era and validates common prognostic factors for Chinese PTL patients.

Primary extranodal diffuse large B-cell lymphomas: Many sites, many entities? Clinico-pathological, immunohistochemical and cytogenetic study of 106 cases

We analyzed the clinicopathological, immunohistochemical and cytogenetic features of 106 extranodal (EN) diffuse large B-cell lymphomas (DLBCLs) from stomach (34 cases), intestine (10), cervico-cephalic region (11), central nervous system (13), testes (21), skin (8), and miscellaneous sites (9). Hans' algorithm and the immunohistochemical double expressor score (DES) for MYC and BCL2 were applied to all cases. A subset of fifty-eight cases were analyzed with fluorescent in situ hybridization (FISH) with specific break apart probes for BCL6, MYC, BCL2, CCND1, BCL10 and MALT1 genes. Clinical records were available for all patients. The immunohistochemical study showed that, in our series of EN-DLBCLs, the Hans' subgroup and the DES differed significantly according to the site of origin. At FISH analysis, BCL6 and BCL2 were the most commonly rearranged genes in non-GC and in GC cases, respectively. Gastrointestinal lymphomas displayed the highest rate of gene rearrangements, often with MYC involvement. One testicular DLBCL showed BCL2/MYC double hit. At survival analysis, cerebral and testicular origin was associated with poor prognosis. In addition, Hans' subgroup and other immunohistochemical markers influenced patients' outcome. In conclusion, our data suggest that immunophenotypic, genetic and survival characteristics of EN-DLBCL are related to the specific primary site of the disease.

Subclonal mutation selection in mouse lymphomagenesis identifies known cancer loci and suggests novel candidates

Determining whether recurrent but rare cancer mutations are bona fide driver mutations remains a bottleneck in cancer research. Here we present the most comprehensive analysis of murine leukemia virus-driven lymphomagenesis produced to date, sequencing 700,000 mutations from >500 malignancies collected at time points throughout tumor development. This scale of data allows novel statistical approaches for identifying selected mutations and yields a high-resolution, genome-wide map of the selective forces surrounding cancer gene loci. We also demonstrate negative selection of mutations that may be deleterious to tumor development indicating novel avenues for therapy. Screening of two BCL2 transgenic models confirmed known drivers of human non-Hodgkin lymphoma, and implicates novel candidates including modifiers of immunosurveillance and MHC loci. Correlating mutations with genotypic and phenotypic features independently of local variance in mutation density also provides support for weakly evidenced cancer genes. An online resource http://mulvdb.org allows customized queries of the entire dataset.

Evidence implicating cancer drivers can be sparse when limited to clonal events. Here, the authors present a retrovirus driven in vivo lymphomagenesis time course including hundreds of thousands of subclonal mutations and demonstrate the utility of these in mapping the selective forces affecting cancer gene loci, including negatively selected mutations.

Target amplicon exome-sequencing identifies promising diagnosis and prognostic markers involved in RTK-RAS and PI3K-AKT signaling as central oncopathways in primary central nervous system lymphoma

Exome-sequencing for somatic mutation detection and copy number variation analysis are effective and valid methods for evaluating human cancers in current molecular medicine. We conducted target amplicon exome-sequencing analyses using PCR target enrichment and next-generation sequencing on Ion Proton semiconductor sequencers. Twenty-seven primary central nervous system lymphoma (PCNSL) specimens and their corresponding noncancerous tissues were used for multiplex PCR amplification to obtain targeted coverages of the entire coding regions of 409 cancer-related genes. The average of the total numbers of somatic mutations including single-nucleotide variations and insertion/deletion mutations in each specimen was 13.3. Of these, the average of the ratios of nonsynonymous substitutions in each specimen was 74.8%. The most frequent mutations in 27 specimens were in PIM1, MYD88, CD79B, DST, IRF4, ERBB3, MYH11, DCC, and KMT2D. Furthermore, somatic mutations of MYH11 were related to poor prognoses in PCNSL patients. Copy number variations were also duplicated and/or deleted from deep-sequencing in segmental genomic islands. In addition to these prognostic marker candidates, analysis of RTK-RAS-MAPK signaling and the PTEN-PI3K-AKT proapoptotic pathway showed that somatic activations and aberrations, respectively, may be involved in a promising central oncopathway harboring mTOR, c-Myc, FOXO1, and p53. This study provides a foundation for molecular targeted therapies based on genome diagnostics and prognosis in PCNSL.

Treatment of Primary Central Nervous System Lymphoma: From Chemotherapy to Small Molecules

Primary central nervous system lymphoma (PCNSL) is a rare form of extranodal non-Hodgkin lymphoma that is typically confined to the brain, eyes, and cerebrospinal fluid (CSF) without evidence of systemic spread. PCNSL is an uncommon tumor, and only four randomized trials and one phase III trial have been completed so far, all in the first-line setting. The prognosis of patients with PCNSL has improved during the past few decades with the introduction of high-dose methotrexate (HD-MTX), which now serves as the backbone of all first-line treatment regimens. Despite recent progress, results after treatment are durable in half of patients, and therapy can be associated with late neurotoxicity. Novel insights into the pathophysiology of PCNSL have identified the B-cell receptor (BCR) pathway as a key mechanism in the pathogenesis of PCNSL. The use of novel agents targeting components of the BCR pathway, namely the Bruton tyrosine kinase (BTK) inhibitor ibrutinib, and immunomodulatory drugs (IMIDs) like lenalidomide and pomalidomide, has so far been limited to patients who have recurrent/refractory PCNSL with promising high response rates. Within the past 5 years, there has been a peak in clinical trials investigating small molecules and novel reagents in the recurrent/refractory setting, including immune checkpoint inhibitors, IMIDs, and BTK and PI3K/AKT/mTOR inhibitors.

Population-based experience on primary central nervous system lymphoma 2000-2012: the incidence is increasing

BACKGROUND

Primary central nervous system lymphomas (PCNSL) are rare lymphomas with a poor prognosis. Recently, an increased incidence has been reported. The present study is a population-based study of all patients with PCNSL in the Uppsala/Örebro region of middle Sweden.

PATIENTS AND METHODS

All patients diagnosed with a PCNSL at Uppsala University Hospital 2000-2012 were identified. Altogether, 96 patients (50 women and 46 men) were included. The median age at diagnosis was 66 years (17-95).

RESULTS

There was a statistically significant increase in age-standardized incidence during the study period, 30 patients were diagnosed in the first half and 66 in the second half of the period. No patient had an HIV-infection. Two patients had undergone kidney transplantation and were treated with immunosuppressive drugs. A high proportion of the patients, 29%, had a history of an autoimmune or inflammatory disease. The prognosis was poor with a median survival of only four months. In the 70 (73%) patients treated with curative intention the median survival was 12 months. Patients treated with high-dose methotrexate, radiotherapy and/or temozolomide appeared to have a better survival. There was no improvement in survival during the study period or after the introduction of rituximab. There also was no difference in any of the analyzed variables that could explain the increased incidence.

CONCLUSION

In this population-based study we could confirm the previously described increased incidence of PCNSL. The prognosis remains poor despite the inclusion of treatment with rituximab during the study period. A high proportion of the patients had a history of an autoimmune or inflammatory disease not previously described but there was no increase during the study period.

Expression of Tim-1 in primary CNS lymphoma

Primary central nervous system lymphoma (PCNSL) is a distinct subtype of extranodal lymphoma with aggressive clinical course and poor outcome. As increased IL‐10/IL‐6 ratio is recognized in the cerebrospinal fluid (CSF) of PCNSL patients, we hypothesized that PCNSL might originate from a population of B cells with high IL‐10‐producing capacity, an equivalent of “regulatory B cells” in mice. We intended in this study to clarify whether Tim‐1, a molecule known as a marker for regulatory B cells in mice, is expressed in PCNSL. By immunohistochemical analysis, Tim‐1 was shown to be positive in as high as 54.2% of PCNSL (26 of 58 samples), while it was positive in 19.1% of systemic diffuse large B‐cell lymphoma (DLBCL) samples (17 of 89 samples; P < 0.001). Tim‐1 expression positively correlated with IL‐10 expression in PCNSL (Cramer's V = 0.55, P < 0.001), and forced expression of Tim‐1 in a PCNSL cell line resulted in increased IL‐10 secretion, suggesting that Tim‐1 is functionally linked with IL‐10 production in PCNSL. Moreover, soluble Tim‐1 was detectable in the CSF of PCNSL patients, and was suggested to parallel disease activity. In summary, PCNSL is characterized by frequent Tim‐1 expression, and its soluble form in CSF may become a useful biomarker for PCNSL.

Recent Advances in Aggressive Large B-cell Lymphomas: A Comprehensive Review

Diffuse large B-cell lymphoma (DLBCL) is an aggressive disease with considerable heterogeneity reflected in the 2008 World Health Organization classification. In recent years, genome-wide assessment of genetic and epigenetic alterations has shed light upon distinct molecular subsets linked to dysregulation of specific genes or pathways. Besides fostering our knowledge regarding the molecular complexity of DLBCL types, these studies have unraveled previously unappreciated genetic lesions, which may be exploited for prognostic and therapeutic purposes. Following the last World Health Organization classification, we have witnessed the emergence of new variants of specific DLBCL entities, such as CD30 DLBCL, human immunodeficiency virus-related and age-related variants of plasmablastic lymphoma, and EBV DLBCL arising in young patients. In this review, we will present an update on the clinical, pathologic, and molecular features of DLBCL incorporating recently gained information with respect to their pathobiology and prognosis. We will emphasize the distinctive features of newly described or emerging variants and highlight advances in our understanding of entities presenting a diagnostic challenge, such as T-cell/histiocyte-rich large B-cell lmphoma and unclassifiable large B-cell lymphomas. Furthermore, we will discuss recent advances in the genomic characterization of DLBCL, as they may relate to prognostication and tailored therapeutic intervention. The information presented in this review derives from English language publications appearing in PubMed throughout December 2015. For a complete outline of this paper, please visit: http://links.lww.com/PAP/A12.

New approaches in primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) has long been associated with an inferior prognosis compared to other aggressive non-Hodgkin's lymphomas (NHLs). However, during the past 10 years an accumulation of clinical experience has demonstrated that long-term progression-free survival (PFS) can be attained in a major proportion of PCNSL patients who receive dose-intensive consolidation chemotherapy and avoid whole brain radiotherapy. One recent approach that has reproducibly demonstrated efficacy for newly diagnosed PCNSL patients is an immunochemotherapy combination regimen used during induction that consists of methotrexate, temozolomide, and rituximab followed by consolidative infusional etoposide plus high-dose cytarabine (EA), administered in first complete remission (CR). Other high-dose chemotherapy-based consolidative regimens have shown efficacy as well. Our goal in this review is to update principles of diagnosis and management as well as data regarding the molecular pathogenesis of PCNSL, information that may constitute a basis for development of more effective therapies required to make additional advances in this phenotype of aggressive NHL.

Targetable genetic features of primary testicular and primary central nervous system lymphomas

Primary central nervous system lymphomas (PCNSLs) and primary testicular lymphomas (PTLs) are extranodal large B-cell lymphomas (LBCLs) with inferior responses to current empiric treatment regimens. To identify targetable genetic features of PCNSL and PTL, we characterized their recurrent somatic mutations, chromosomal rearrangements, copy number alterations (CNAs), and associated driver genes, and compared these comprehensive genetic signatures to those of diffuse LBCL and primary mediastinal large B-cell lymphoma (PMBL). These studies identify unique combinations of genetic alterations in discrete LBCL subtypes and subtype-selective bases for targeted therapy. PCNSLs and PTLs frequently exhibit genomic instability, and near-uniform, often biallelic, CDKN2A loss with rare TP53 mutations. PCNSLs and PTLs also use multiple genetic mechanisms to target key genes and pathways and exhibit near-uniform oncogenic Toll-like receptor signaling as a result of MYD88 mutation and/or NFKBIZ amplification, frequent concurrent B-cell receptor pathway activation, and deregulation of BCL6. Of great interest, PCNSLs and PTLs also have frequent 9p24.1/PD-L1/PD-L2 CNAs and additional translocations of these loci, structural bases of immune evasion that are shared with PMBL.

High-resolution copy number analysis of paired normal-tumor samples from diffuse large B cell lymphoma

Copy number analysis can be useful for assessing prognosis in diffuse large B cell lymphoma (DLBCL). We analyzed copy number data from tumor samples of 60 patients diagnosed with DLBCL de novo and their matched normal samples. We detected 63 recurrent copy number alterations (CNAs), including 33 gains, 30 losses, and nine recurrent acquired copy number neutral loss of heterozygosity (CNN-LOH). Interestingly, 20 % of cases acquired CNN-LOH of 6p21 locus, which involves the HLA region. In normal cells, there were no CNAs but we observed CNN-LOH involving some key lymphoma regions such as 6p21 and 9p24.1 (5 %) and 17p13.1 (2.5 %) in DLBCL patients. Furthermore, a model with some specific CNA was able to predict the subtype of DLBCL, 1p36.32 and 10q23.31 losses being restricted to germinal center B cell-like (GCB) DLBCL. In contrast, 8p23.3 losses and 11q24.3 gains were strongly associated with the non-GCB subtype. A poor prognosis was associated with biallelic inactivation of TP53 or 18p11.32 losses, while prognosis was better in cases carrying 11q24.3 gains. In summary, CNA abnormalities identify specific DLBCL groups, and we describe CNN-LOH in germline cells from DLBCL patients that are associated with genes that probably play a key role in DLBCL development.

Primary CNS lymphoma

Primary diffuse large B-cell lymphoma (DLBCL) of the central nervous system is an aggressive malignancy that exhibits unique biological features and characteristic clinical behaviour, with overall long-term survival rates of around 20–40 %. Clinical outcome has improved following the advent of chemoradiation protocols incorporating high-dose methotrexate in the mid-1980s, but disease relapse and adverse neurocognitive sequelae remain major clinical challenges. To address this, investigators have focused on improving drug therapy with novel cytotoxic combinations, monoclonal antibody therapy, and intensive chemotherapy consolidation approaches, in an attempt to improve disease control whilst reducing the requirement for whole-brain radiotherapy. Outcomes for patients that are older, immunocompromised, or have relapsed/refractory disease remain unsatisfactory and there is a paucity of clinical trial data to guide treatment of these groups. This review highlights recent advances in pathobiology, imaging, and clinical management of PCNSL and looks ahead to research priorities for this rare and challenging lymphoid malignancy.

Impaired T-Cell Function in B-Cell Lymphoma: A Direct Consequence of Events at the Immunological Synapse?

Tumors can escape immune destruction through the development of antigen loss variants and loss of antigen processing/presentation pathways, thereby rendering them invisible to T cells. Alternatively, mechanisms of peripheral T-cell tolerance that would normally be important for protection from the development of autoimmunity may also be co-opted to (i) generate an immuno-inhibitory tumor environment, (ii) promote development of regulatory cell populations, or (iii) cell-intrinsically inactivate tumor-specific T cells. Emerging evidence suggests that T-cell function is impaired in hematological malignancies, which may manifest from cognate interactions between T cells and the tumor. The immunological synapse forms the cognate T-cell and antigen-presenting cell interaction and is the site where key signalling events, including those delivered by co-inhibitory receptors, that determine the fate of T cells occur. Here, we review evidence that events at the immune synapse between T cells and malignant B cells and alterations in immune synapse function may contribute to loss of T-cell function in B-cell malignancies.

Genome-Wide Analysis Uncovers Novel Recurrent Alterations in Primary Central Nervous System Lymphomas

PURPOSE

Primary central nervous system lymphoma (PCNSL) is an aggressive non-Hodgkin lymphoma confined to the central nervous system. Whether there is a PCNSL-specific genomic signature and, if so, how it differs from systemic diffuse large B-cell lymphoma (DLBCL) is uncertain.

EXPERIMENTAL DESIGN

We performed a comprehensive genomic study of tumor samples from 19 immunocompetent PCNSL patients. Testing comprised array-comparative genomic hybridization and whole exome sequencing.

RESULTS

Biallelic inactivation of TOX and PRKCD was recurrently found in PCNSL but not in systemic DLBCL, suggesting a specific role in PCNSL pathogenesis. In addition, we found a high prevalence of MYD88 mutations (79%) and CDKN2A biallelic loss (60%). Several genes recurrently affected in PCNSL were common with systemic DLBCL, including loss of TNFAIP3, PRDM1, GNA13, TMEM30A, TBL1XR1, B2M, CD58, activating mutations of CD79B, CARD11, and translocations IgH-BCL6. Overall, B-cell receptor/Toll-like receptor/NF-κB pathways were altered in >90% of PNCSL, highlighting its value for targeted therapeutic approaches. Furthermore, integrated analysis showed enrichment of pathways associated with immune response, proliferation, apoptosis, and lymphocyte differentiation.

CONCLUSIONS

In summary, genome-wide analysis uncovered novel recurrent alterations, including TOX and PRKCD, helping to differentiate PCNSL from systemic DLBCL and related lymphomas.

The histological classification of diffuse large B-cell lymphomas

Diffuse large B-cell lymphomas (DLBCLs) are aggressive B-cell neoplasms with considerable clinical, biologic, and pathologic diversity, in part reflecting the functional diversity of the B-cell system and multiple pathways of transformation. In recent years, the advent of new high-throughput genomic technologies has provided new insights into the biology of DLBCL, leading to the identification of distinct molecular identities and novel pathogenetic pathways. This increasing complexity had led to an expanding number of entities in the World Health Organization classification. Using a multi-modality approach, the updated 2008 classification delineated some new subgroups, including DLBCLs associated with particular age groups or specific anatomic sites, as well as two borderline categories (tumors at the interface between classical Hodgkin lymphoma and DLBCL as well as between Burkitt lymphoma and DLBCL). This article reviews the histopathologic features of the various aggressive B-cell lymphoma subtypes included in the 2008 classification, with emphasis on some of the new entities as well as areas of diagnostic challenge.

Differential expression of Toll-like receptor (TLR) and B cell receptor (BCR) signaling molecules in primary diffuse large B-cell lymphoma of the central nervous system

Primary diffuse large B-cell lymphoma of the central nervous system (CNS DLBCL) is a distinct and aggressive lymphoma that is confined to CNS. Since, central nervous system is barrier-protected and immunologically silent; role of TLR/BCR signaling in pathogenesis and biology of CNS DLBCL is intriguing. Genomic mutations in key regulators of TLR/BCR signaling pathway (MYD88/CD79B/CARD11) have recently been reported in this disease. These observations raised possible implications in novel targeted therapies; however, expression pattern of molecules related to TLR/BCR pathways in this lymphoma remains unknown. We have analyzed the expression of 19 genes encoding TLR/BCR pathways and targets in CNS DLBCLs (n = 20) by Nanostring nCounter™ analysis and compared it with expression patterns in purified reactive B-lymphocytes and systemic diffuse large B cell lymphoma (DLBCL) (n = 20). Relative expression of TLR4, TLR5, TLR9, CD79B and BLNK was higher in CNS DLBCLs than in control B-lymphocytes; where as TLR7, MALT1, BCL10, CD79A and LYN was lower in CNS DLBCLs (P < 0.0001). When compared with systemic DLBCL samples, higher expression of TLR9, CD79B, CARD11, LYN and BLNK was noted in CNS DLBCL (>1.5 fold change; P < 0.01). The B cell receptor molecules like BLNK and CD79B were also associated with higher expression of MYD88 dependent TLRs (TLR4/5/9). In conclusion, we have shown over expression of TLR/BCR related genes or their targets, where genomic mutations have commonly been identified in CNS DLBCL. We have also demonstrated that TLR over expression closely relate with up regulation of genes associated with BCR pathway like CD79B/BLNK and CARD11, which play an important role in NF-kB pathway activation. Our results provide an important insight into the possibility of TLR and/or B-cell receptor signaling molecules as possible therapeutic targets in CNS DLBCL.

The mutational pattern of primary lymphoma of the central nervous system determined by whole-exome sequencing

To decipher the mutational pattern of primary CNS lymphoma (PCNSL), we performed whole-exome sequencing to a median coverage of 103 × followed by mutation verification in 9 PCNSL and validation using Sanger sequencing in 22 PCNSL. We identified a median of 202 (range: 139-251) potentially somatic single nucleotide variants (SNV) and 14 small indels (range: 7-22) with potentially protein-changing features per PCNSL. Mutations affected the B-cell receptor, toll-like receptor, and NF-κB and genes involved in chromatin structure and modifications, cell-cycle regulation, and immune recognition. A median of 22.2% (range: 20.0-24.7%) of somatic SNVs in 9 PCNSL overlaps with the RGYW motif targeted by somatic hypermutation (SHM); a median of 7.9% (range: 6.2-12.6%) affects its hotspot position suggesting a major impact of SHM on PCNSL pathogenesis. In addition to the well-known targets of aberrant SHM (aSHM) (PIM1), our data suggest new targets of aSHM (KLHL14, OSBPL10, and SUSD2). Among the four most frequently mutated genes was ODZ4 showing protein-changing mutations in 4/9 PCNSL. Together with mutations affecting CSMD2, CSMD3, and PTPRD, these findings may suggest that alterations in genes having a role in CNS development may facilitate diffuse large B-cell lymphoma manifestation in the CNS. This may point to intriguing mechanisms of CNS tropism in PCNSL.

Expression of KLF4 is a predictive marker for survival in pediatric Burkitt lymphoma

Krüppel-like factor 4 (KLF4) is expressed in a variety of tissues with diverse physiological functions and activities. KLF4 can also function as a tumor suppressor or an oncogene, depending on the cellular context. Its role in hematological malignancies is controversial. This study examined the expression levels of KLF4 by immunohistochemistry in 73 pediatric non-Hodgkin lymphomas (NHLs) in a tissue microarray and also on several B-NHL cell lines. Elevated levels of KLF4 expression were detected in 66% of lymphoma cases and were more frequent in the Burkitt lymphoma (p = 0.05) subtype. There was a significant predictive power for outcome with low KLF4 expression, predicting a favorable overall survival compared to high levels. Multivariate analyses confirmed the association of KLF4 expression with unfavorable overall survival (p < 0.005). These findings were consistent with analyses in existing NHL microarray datasets. The present findings revealed that KLF4 is overexpressed in Burkitt pediatric lymphoma and is a potential biomarker for inferior overall survival.

Progress in central nervous system lymphomas

Until recently, primary central nervous system lymphoma (PCNSL) was associated with a uniformly dismal prognosis. It is now reasonable to anticipate long-term survival and possibly cure for a significant proportion of patients diagnosed with PCNSL. Accumulated data generated over the past 10 years has provided evidence that long-term progression-free survival (PFS) can reproducibly be attained in a significant fraction of PCNSL patients that receive dose-intensive chemotherapy consolidation, without whole brain radiotherapy. One consolidative regimen that has reproducibly demonstrated promise is the combination of infusional etoposide plus high-dose cytarabine (EA), administered in first complete remission after methotrexate, temozolomide and rituximab-based induction. Given evolving principles of management and the mounting evidence for reproducible improvements in survival rates in prospective clinical series, our goal in this review is to highlight and update principles in diagnosis, staging and management as well as to review data regarding the pathogenesis of central nervous system lymphomas, information that is likely to constitute a basis for the implementation of novel therapies that are requisite for further progress in this unique phenotype of non-Hodgkin lymphoma.

High-resolution genomic copy number profiling of primary intraocular lymphoma by single nucleotide polymorphism microarrays

Primary intraocular lymphoma (PIOL) is a rare lymphoma. Because of difficulties in obtaining tissue samples, little is known about the disease's genetic features. In order to clarify these features, we carried out single nucleotide polymorphism array karyotyping of IOL using genomic DNA extracted from vitreous fluid. We analyzed 33 samples of IOLs consisting of 16 PIOLs, 12 IOLs with a central nervous system (CNS) lesion at diagnosis (IOCNSL), and five secondary IOLs following systemic lymphoma. All were B-cell type. We identified recurrent copy number (CN) gain regions in PIOLs, most frequently on chromosome 1q followed by 18q and 19q. Chromosome 6q was the most frequent loss region. Although these CN gain regions of PIOL were in common with those of IOCNSL, loss of 6q22.33 containing PTPRK and 9p21.3 containing CDKN2A were more frequently deleted in IOCNSL. Large CN loss in 6q was detected in three of four PIOL patients who had early CNS development and short survival periods, whereas long-term survivors did not have such deletions. There was a correlation between gain of the IL-10 gene located on 1q and intravitreal interleukin-10 concentration, which was higher in IOL than in benign uveitis. The results suggest that IOCNSL is a highly malignant form of PIOL that infiltrates into the CNS at an early stage. They also indicate that genetic differences between PIOL and primary CNS lymphoma need to be clarified.