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Abstract: State-of-the-art response assessment of central nervous system lymphoma (CNSL) by magnetic resonance imaging is challenging and an insufficient predictor of treatment outcomes. Accordingly, the development of novel risk stratification strategies in CNSL is a high unmet medical need. We applied ultrasensitive circulating tumor DNA (ctDNA) sequencing to 146 plasma and cerebrospinal fluid (CSF) samples from 67 patients, aiming to develop an entirely noninvasive dynamic risk model considering clinical and molecular features of CNSL. Our ultrasensitive method allowed for the detection of CNSL-derived mutations in plasma ctDNA with high concordance to CSF and tumor tissue. Undetectable plasma ctDNA at baseline was associated with favorable outcomes. We tracked tumor-specific mutations in plasma-derived ctDNA over time and developed a novel CNSL biomarker based on this information: peripheral residual disease (PRD). Persistence of PRD after treatment was highly predictive of relapse. Integrating established baseline clinical risk factors with assessment of radiographic response and PRD during treatment resulted in the development and independent validation of a novel tool for risk stratification: molecular prognostic index for CNSL (MOP-C). MOP-C proved to be highly predictive of outcomes in patients with CNSL (failure-free survival hazard ratio per risk group of 6.60; 95% confidence interval, 3.12-13.97; P < .0001) and is publicly available at www.mop-c.com. Our results highlight the role of ctDNA sequencing in CNSL. MOP-C has the potential to improve the current standard of clinical risk stratification and radiographic response assessment in patients with CNSL, ultimately paving the way toward individualized treatment., (© 2024 American Society of Hematology. Published by Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.)

Glioneuronal tumors are a heterogenous group of CNS neoplasms that can be challenging to accurately diagnose. Molecular methods are highly useful in classifying these tumors-distinguishing precise classes from their histological mimics and identifying previously unrecognized types of tumors. Using an unsupervised visualization approach of DNA methylation data, we identified a novel group of tumors (n = 20) that formed a cluster separate from all established CNS tumor types. Molecular analyses revealed ATRX alterations (in 16/16 cases by DNA sequencing and/or immunohistochemistry) as well as potentially targetable gene fusions involving receptor tyrosine-kinases (RTK; mostly NTRK1-3) in all of these tumors (16/16; 100%). In addition, copy number profiling showed homozygous deletions of CDKN2A/B in 55% of cases. Histological and immunohistochemical investigations revealed glioneuronal tumors with isomorphic, round and often condensed nuclei, perinuclear clearing, high mitotic activity and microvascular proliferation. Tumors were mainly located supratentorially (84%) and occurred in patients with a median age of 19 years. Survival data were limited (n = 18) but point towards a more aggressive biology as compared to other glioneuronal tumors (median progression-free survival 12.5 months). Given their molecular characteristics in addition to anaplastic features, we suggest the term glioneuronal tumor with ATRX alteration, kinase fusion and anaplastic features (GTAKA) to describe these tumors. In summary, our findings highlight a novel type of glioneuronal tumor driven by different RTK fusions accompanied by recurrent alterations in ATRX and homozygous deletions of CDKN2A/B. Targeted approaches such as NTRK inhibition might represent a therapeutic option for patients suffering from these tumors., (© 2023. The Author(s).)

The management of primary central nervous system (PCNSL) is one of the most controversial topics in neuro-oncology because of the complexity of the disease and the limited number of controlled studies available. In 2021, given recent advances and the publication of practice-changing randomized trials, the European Association of Neuro-Oncology (EANO) created a multidisciplinary task force to update the previously published evidence-based guidelines for immunocompetent adult patients with PCNSL and added a section on immunosuppressed patients. The guideline provides consensus considerations and recommendations for the treatment of PCNSL, including intraocular manifestations and specific management of the elderly. The main changes from the previous guideline include strengthened evidence for the consolidation with ASCT in first-line treatment, prospectively assessed chemotherapy combinations for both young and elderly patients, clarification of the role of rituximab even though the data remain inconclusive, of the role of new agents, and the incorporation of immunosuppressed patients and primary ocular lymphoma. The guideline should aid the clinicians in everyday practice and decision making and serve as a basis for future research in the field., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

219 HIV-negative adults ≤70 years with primary CNS lymphoma (PCNSL) were enrolled in the randomized IELSG32 trial. Enrolled patients were randomly assigned to receive methotrexate-cytarabine (arm A), or methotrexate-cytarabine-rituximab (B), or methotrexate-cytarabine-thiotepa-rituximab (MATRix; arm C). A second randomization allocated patients with responsive/stable disease to whole-brain irradiation (WBRT) or carmustine-thiotepa-conditioned autologous transplantation (ASCT). First results, after a median follow-up of 30 months, showed that MATRix significantly improves outcome, with both WBRT and ASCT being similarly effective. However, sound assessment of overall survival (OS), efficacy of salvage therapy, late complications, secondary tumors, and cognitive impairment requires longer follow-up. Herein, we report the results of this trial at a median follow-up of 88 months. As main findings, MATRix was associated with excellent long-lasting outcome, with a 7-year OS of 21%, 37%, and 56% respectively for arms A, B, and C. Notably, patients treated with MATRix and consolidation had a 7-year OS of 70%. The superiority of arm B on arm A suggests a benefit from the addition of rituximab. Comparable efficacy of WBRT and ASCT was confirmed. Salvage therapy was ineffective; benefit was recorded only in patients with late relapse re-treated with methotrexate. Eight (4%) patients developed a second cancer. Importantly, MATRix and ASCT did not result in higher non-relapse mortality or second tumors incidence. Patients who received WBRT experienced impairment in attentiveness and executive functions, whereas patients undergoing ASCT experienced improvement in these functions as well as in memory and quality of life., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Primary central nervous system lymphoma (PCNSL) is a rare type of aggressive lymphoma of the central nervous system. Treatment strategies improved significantly over the past decades differ regionally but mainly consist of rituximab and high-dosed methotrexate (MTX)-based therapies., Methods: We assessed clinical outcomes of 100 patients with newly diagnosed PCNSL between 2010-2020 at the University Hospital of Cologne, Germany., Results: Patients were 23-88 years of age and either treated with MTX-based regimens (PRIMAIN, MARTA, MATRix), individual regimens, or best supportive care, respectively. Overall response rates were generally high (66,7-83,8%), but different organ toxicities required dose adjustments in most groups. Two-year overall survival rates were 57,9% (PRIMAIN), 63,6% (MARTA), 65,4% (MATRix), and 37,5% (Other), respectively. Out of 9 patients suffering from relapse >12 months from primary diagnosis, 7 patients (77,8%) received methotrexate-based salvage therapy with 2-year overall survival of 4/6 patients (66,7%)., Conclusion: Although a relevant proportion of patients are not eligible for clinical trials due to age, performance status, or comorbidities, these results prove feasibility of different MTX-based treatment strategies in clinical routine. Even elderly patients displayed surprisingly favorable outcomes. However, with compromising organ toxicities, reduction of intensity should be part of strategies in future clinical trials., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The immunoglobulin (Ig) heavy and light chain variable gene mutational pattern of the B cell receptor (BCR) in primary central nervous system (CNS) lymphoma (PCNSL) cells suggests antigenic selection to drive pathogenesis and confinement to the CNS. This hypothesis is supported by the observation that the tumor B cell receptor (tBCR) of PCNSL is polyreactive and may be stimulated by CNS proteins. To obtain further insight into the role of the germinal center (GC) reaction on BCR reactivity, we constructed recombinant antibodies (recAb) with Ig heavy and light chain sequences of the corresponding naive BCR (nBCR) by reverting tBCR somatic mutations in 10 PCNSL. Analysis of nBCR-derived recAb reactivity by a protein microarray and immunoprecipitation demonstrated auto- and polyreactivity in all cases. Self-/polyreactivity was not lost during the GC reaction; surprisingly, tBCR significantly increased self-/polyreactivity. In addition to proteins recognized by both the nBCR and tBCR, tBCR gained self-/polyreactivity particularly for proteins expressed in the CNS including proteins of oligodendrocytes/myelin, the S100 protein family, and splicing factors. Thus, in PCNSL pathogenesis, a faulty GC reaction may increase self-/polyreactivity, hereby facilitating BCR signaling via multiple CNS antigens, and may ultimately foster tumor cell survival in the CNS.

Objective: To determine whether a fraction of patients with primary CNS lymphoma (PCNSL) had been cured by systemic and intraventricular methotrexate- and cytarabine-based chemotherapy (Bonn protocol) after a very long-term follow-up of nearly 20 years., Methods: Sixty-five patients (median age 62 years, range 27-75; median Karnofsky performance score 70, range 20-90) had been treated with systemic and intraventricular polychemotherapy without whole brain radiotherapy from September 1995 until December 2001. All patients still alive in 2019 were contacted and interviewed on their current life situation., Results: Median follow-up for surviving patients was 19.6 years (17.5-23.3 years). Out of 65 patients, 11 (17%) were still alive. Six of those never experienced any relapse. For the whole study population, median overall survival (OS) was 4.4 years (95% confidence interval [CI] 2.9-5.9); for patients ≤60 years, 11.0 years (95% CI 4.8-17.0). The 10-year OS rate for the entire cohort was 29% and the estimated 20-year OS rate was 19%. Four late relapses were observed after 9.8, 10.3, 13.3, and 21.0 years., Conclusion: At a median follow-up of 19.6 years, 17% of patients were alive and free of tumor; however, even after response for decades, an inherent risk of relapse, either systemic or cerebral, characterizes the biology of PCNSL., Classification of Evidence: This work provides Class III evidence that PCNSL treatment with methotrexate-based polychemotherapy including intraventricular therapy is associated with long-term disease control in some patients., (Copyright © 2020 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

C-X-C chemokine receptor 4 (CXCR4) is a transmembrane chemokine receptor involved in growth, survival, and dissemination of cancer, including aggressive B-cell lymphoma. MRI is the standard imaging technology for central nervous system (CNS) involvement of B-cell lymphoma and provides high sensitivity but moderate specificity. Therefore, novel molecular and functional imaging strategies are urgently required. Methods: In this proof-of-concept study, 11 patients with lymphoma of the CNS (8 primary and 3 secondary involvement) were imaged with the CXCR4-directed PET tracer 68 Ga-pentixafor. To evaluate the predictive value of this imaging modality, treatment response, as determined by MRI, was correlated with quantification of CXCR4 expression by 68 Ga-pentixafor PET in vivo before initiation of treatment in 7 of 11 patients. Results: 68 Ga-pentixafor PET showed excellent contrast with the surrounding brain parenchyma in all patients with active disease. Furthermore, initial CXCR4 uptake determined by PET correlated with subsequent treatment response as assessed by MRI. Conclusion: 68 Ga-pentixafor PET represents a novel diagnostic tool for CNS lymphoma with potential implications for theranostic approaches as well as response and risk assessment., (© 2020 by the Society of Nuclear Medicine and Molecular Imaging.)

In newly diagnosed systemic diffuse large B-cell lymphoma, next-generation sequencing of plasma-derived cell-free DNA (cfDNA) detects somatic mutations as accurate as genotyping of the tumor biopsy. A distinct diffuse large B-cell lymphoma entity confined to the central nervous system is primary central nervous system lymphoma (PCNSL), which requires intracerebral biopsy and neuropathologic analysis to establish the diagnosis. So far, a biomarker for diagnosis and follow-up of PCNSL that can be investigated in blood has not been identified. This article addresses the question whether somatic mutations of the CD79B and MYD88 driver genes of PCNSL can be detected in cfDNA at disease diagnosis. Stereotactic biopsies and cfDNA of 27 PCNSL patients were analyzed for CD79B and MYD88 mutations. As control, cfDNA derived from six healthy volunteers was used. CD79B and MYD88 hot spot mutations were identified in 16 of 27 (59%) and 23 of 27 (85%) PCNSL biopsies, respectively, but only in 0 of 27 (0%) and 1 of 27 (4%) corresponding cfDNA samples, respectively. In cfDNA of one of four patients with Waldenstrom disease, as a further control, the MYD88 L265P mutation was readily detected, despite complete clinical remission. These data suggest that in PCNSL even if they carry such mutations, alterations of CD79B and MYD88 cannot be reliably detected in blood-derived cfDNA obtained before intracerebral biopsy., (Copyright © 2020 Association for Molecular Pathology and American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Primary lymphomas of the central nervous system (PCNSL) are diffuse large B-cell lymphomas (DLBCLs) confined to the central nervous system (CNS). We here performed array-based DNA methylation analyses of 26 PCNSL and 78 DLBCL and validated our findings in an independent dataset. We identified 2847 CpGs differentially methylated between PCNSL and non-CNS-DLBCL. Neither a supervised analysis using these CpGs nor application of 3 CpG classifiers selected for class separation unambiguously separated PCNSL from non-CNS-DLBCL. Remarkably, 6/78 non-CNS-DLBCL consistently segregated with PCNSL, which displayed molecular features typical for PCNSL. Our findings suggest that a subset of non-CNS-DLBCL exists which molecularly resembles PCNSL., (© 2018 Wiley Periodicals, Inc.)

Accurate pathological diagnosis is crucial for optimal management of patients with cancer. For the approximately 100 known tumour types of the central nervous system, standardization of the diagnostic process has been shown to be particularly challenging-with substantial inter-observer variability in the histopathological diagnosis of many tumour types. Here we present a comprehensive approach for the DNA methylation-based classification of central nervous system tumours across all entities and age groups, and demonstrate its application in a routine diagnostic setting. We show that the availability of this method may have a substantial impact on diagnostic precision compared to standard methods, resulting in a change of diagnosis in up to 12% of prospective cases. For broader accessibility, we have designed a free online classifier tool, the use of which does not require any additional onsite data processing. Our results provide a blueprint for the generation of machine-learning-based tumour classifiers across other cancer entities, with the potential to fundamentally transform tumour pathology.

Background: The International Extranodal Lymphoma Study Group-32 (IELSG32) trial is an international randomised phase 2 study that addresses two key clinical questions in the treatment of patients with newly diagnosed primary CNS lymphoma. Results of the first randomisation have demonstrated that methotrexate, cytarabine, thiotepa, and rituximab (called the MATRix regimen) is the induction combination associated with significantly better outcome compared with the other induction combinations tested. Here, we report the results of the second randomisation that addresses the efficacy of myeloablative chemotherapy supported by autologous stem-cell transplantation (ASCT), as an alternative to whole-brain radiotherapy (WBRT), as consolidation after high-dose-methotrexate-based chemoimmunotherapy., Methods: HIV-negative patients (aged 18-70 years) with newly diagnosed primary CNS lymphoma and an Eastern Cooperative Oncology Group performance status of 0-3 were randomly assigned to receive four courses of methotrexate 3·5 g/m 2 on day 1 plus cytarabine 2 g/m 2 twice daily on days 2 and 3 (group A); or the same combination plus two doses of rituximab 375 mg/m 2 on days -5 and 0 (group B); or the same methotrexate-cytarabine-rituximab combination plus thiotepa 30 mg/m 2 on day 4 (group C), with the three groups repeating treatment every 3 weeks. Patients with responsive or stable disease after induction treatment, with adequate autologous peripheral blood stem-cell collection, and without persistent iatrogenic side-effects, were eligible for the second randomisation between WBRT (photons of 4-10 MeV; five fractions per week; fraction size 180 cGy; started within 4 weeks from the last induction course; group D) and carmustine-thiotepa conditioned ASCT (carmustine 400 mg/m 2 on day -6, and thiotepa 5 mg/kg every 12 h on days -5 and -4, followed by reinfusion of autologous peripheral blood stem cells; group E). A permuted block randomised design was adopted for both randomisations, and a computer-generated randomisation list was used within each stratum. No masking after assignment to intervention was adopted. The primary endpoint was 2-year progression-free survival, with induction group and response to induction chemotherapy as stratification parameters. Analyses were done on a modified intention-to-treat basis. This study is registered with ClinicalTrials.gov, number NCT01011920., Findings: Between Feb 19, 2010, and Aug 27, 2014, 227 patients were recruited from 53 centres in five countries. 219 of 227 enrolled patients were assessable. Of the 122 patients eligible for the second randomisation, 118 patients were randomly assigned to WBRT or ASCT (59 patients per group) and constitute the study population. WBRT and ASCT were both effective, and achieved the predetermined efficacy threshold of at least 40 progression-free survivors at 2 years among the first 52 patients in both groups D and E. There were no significant differences in 2-year progression-free survival between WBRT and ASCT: 80% (95% CI 70-90) in group D and 69% (59-79) in group E (hazard ratio 1·50, 95% CI 0·83-2·71; p=0·17). Both consolidation therapies were well tolerated. Grade 4 non-haematological toxicity was uncommon; as expected, haematological toxicity was more common in patients treated with ASCT than in those who received WBRT. Two toxic deaths (infections) were recorded, both in patients who received ASCT., Interpretation: WBRT and ASCT are both feasible and effective as consolidation therapies after high-dose methotrexate-based chemoimmunotherapy in patients aged 70 years or younger with primary CNS lymphoma. The risks and implications of cognitive impairment after WBRT should be considered at the time of therapeutic decision., Funding: Agenzia Italiana del Farmaco, Cancer Research UK, Oncosuisse, and Swiss National Science Foundation., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: High-dose methotrexate-based chemotherapy is standard for primary CNS lymphoma, but most patients relapse. High-dose chemotherapy with autologous stem cell transplantation (HCT-ASCT) is supposed to overcome the blood-brain barrier and eliminate residual disease in the CNS. We aimed to investigate the safety and efficacy of HCT-ASCT in patients with newly diagnosed primary CNS lymphoma., Methods: In this prospective, single-arm, phase 2 trial, we recruited patients aged 18-65 years with newly diagnosed primary CNS lymphoma and immunocompetence, with no limitation on clinical performance status, from 15 hospitals in Germany. Patients received five courses of intravenous rituximab 375 mg/m(2) (7 days before first high-dose methotrexate course and then every 10 days) and four courses of intravenous high-dose methotrexate 8000 mg/m(2) (every 10 days) and then two courses of intravenous rituximab 375 mg/m(2) (day 1), cytarabine 3 g/m(2) (days 2 and 3), and thiotepa 40 mg/m(2) (day 3). 3 weeks after the last course, patients commenced intravenous HCT-ASCT (rituximab 375 mg/m(2) [day 1], carmustine 400 mg/m(2) [day 2], thiotepa 2 × 5 mg/kg [days 3 and 4], and infusion of stem cells [day 7]), irrespective of response status after induction. We restricted radiotherapy to patients without complete response after HCT-ASCT. The primary endpoint was complete response at day 30 after HCT-ASCT in all registered eligible patients who received at least 1 day of study treatment. This trial is registered at ClinicalTrials.gov, number NCT00647049., Findings: Between Jan 18, 2007, and May 23, 2011, we recruited 81 patients, of whom two (2%) were excluded, therefore we included 79 (98%) patients in the analysis. All patients started induction treatment; 73 (92%) commenced HCT-ASCT. 61 (77·2% [95% CI 66·1-86·6]) patients achieved a complete response. During induction treatment, the most common grade 3 toxicity was anaemia (37 [47%]) and the most common grade 4 toxicity was thrombocytopenia (50 [63%]). During HCT-ASCT, the most common grade 3 toxicity was fever (50 [68%] of 73) and the most common grade 4 toxicity was leucopenia (68 [93%] of 73). We recorded four (5%) treatment-related deaths (three [4%] during induction and one [1%] 4 weeks after HCT-ASCT)., Interpretation: HCT-ASCT with thiotepa and carmustine is an effective treatment option in young patients with newly diagnosed primary CNS lymphoma, but further comparative studies are needed., Funding: University Hospital Freiburg and Amgen., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Primary central nervous system (CNS) lymphoma (PCNSL) is a mature lymphoma of the diffuse large B-cell lymphoma (DLBCL) type confined to the CNS. Despite cytomorphological similarities between PCNSL and systemic DLBCL, molecular differences between both entities have been identified. The exclusively topographical restriction of PCNSL to the CNS is an unexplained mystery. To address the question of whether the unique lymphatic drainage system of the CNS, which differs from that of other organs, may play a role for this peculiar behavior, we investigated a series of 20 PCNSLs for the presence of lymphatic vessels by immunohistochemistry for Lyve-1, podoplanin, and Prox-1 expression. All PCNSLs lacked lymphatic vessels and, in this regard, were similar to 20 glioblastoma multiforme samples. In contrast to these tumors, all of which were located in the deep brain parenchyma, dural and meningeal DLBCL harbored lymphatic vessels that expressed Lyve-1 (3/8 tumors), podoplanin (5/8 tumors), and Prox-1 (5/8 tumors) in areas where the tumors had invaded the fibrous tissue of the dura. These data indicate that local topographical characteristics of the specific lymphatic drainage system may contribute to confinement of the tumor cells in PCNSL and malignant gliomas., (© 2016 American Association of Neuropathologists, Inc. All rights reserved.)

Background: Standard treatment for patients with primary CNS lymphoma remains to be defined. Active therapies are often associated with increased risk of haematological or neurological toxicity. In this trial, we addressed the tolerability and efficacy of adding rituximab with or without thiotepa to methotrexate-cytarabine combination therapy (the MATRix regimen), followed by a second randomisation comparing consolidation with whole-brain radiotherapy or autologous stem cell transplantation in patients with primary CNS lymphoma. We report the results of the first randomisation in this Article., Methods: For the international randomised phase 2 International Extranodal Lymphoma Study Group-32 (IELSG32) trial, HIV-negative patients (aged 18-70 years) with newly diagnosed primary CNS lymphoma and measurable disease were enrolled from 53 cancer centres in five European countries (Denmark, Germany, Italy, Switzerland, and the UK) and randomly assigned (1:1:1) to receive four courses of methotrexate 3·5 g/m(2) on day 1 plus cytarabine 2 g/m(2) twice daily on days 2 and 3 (group A); or the same combination plus two doses of rituximab 375 mg/m(2) on days -5 and 0 (group B); or the same methotrexate-cytarabine-rituximab combination plus thiotepa 30 mg/m(2) on day 4 (group C), with the three groups repeating treatment every 3 weeks. Patients with responsive or stable disease after the first stage were then randomly allocated between whole-brain radiotherapy and autologous stem cell transplantation. A permuted blocks randomised design (block size four) was used for both randomisations, and a computer-generated randomisation list was used within each stratum to preserve allocation concealment. Randomisation was stratified by IELSG risk score (low vs intermediate vs high). No masking after assignment to intervention was used. The primary endpoint of the first randomisation was the complete remission rate, analysed by modified intention to treat. This study is registered with ClinicalTrials.gov, number NCT01011920., Findings: Between Feb 19, 2010, and Aug 27, 2014, 227 eligible patients were recruited. 219 of these 227 enrolled patients were assessable. At median follow-up of 30 months (IQR 22-38), patients treated with rituximab and thiotepa had a complete remission rate of 49% (95% CI 38-60), compared with 23% (14-31) of those treated with methotrexate-cytarabine alone (hazard ratio 0·46, 95% CI 0·28-0·74) and 30% (21-42) of those treated with methotrexate-cytarabine plus rituximab (0·61, 0·40-0·94). Grade 4 haematological toxicity was more frequent in patients treated with methotrexate-cytarabine plus rituximab and thiotepa, but infective complications were similar in the three groups. The most common grade 3-4 adverse events in all three groups were neutropenia, thrombocytopenia, anaemia, and febrile neutropenia or infections. 13 (6%) patients died of toxicity., Interpretation: With the limitations of a randomised phase 2 study design, the IELSG32 trial provides a high level of evidence supporting the use of MATRix combination as the new standard chemoimmunotherapy for patients aged up to 70 years with newly diagnosed primary CNS lymphoma and as the control group for future randomised trials., Funding: Associazione Italiana del Farmaco, Cancer Research UK, Oncosuisse, and Swiss National Foundation., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Primary lymphoma of the CNS (PCNSL) is a diffuse large B cell lymphoma confined to the CNS. To elucidate its peculiar organ tropism, we generated recombinant Abs (recAbs) identical to the BCR of 23 PCNSLs from immunocompetent patients. Although none of the recAbs showed self-reactivity upon testing with common autoantigens, they recognized 1547 proteins present on a large-scale protein microarray, indicating polyreactivity. Interestingly, proteins (GRINL1A, centaurin-α, BAIAP2) recognized by the recAbs are physiologically expressed by CNS neurons. Furthermore, 87% (20/23) of the recAbs, including all Abs derived from IGHV4-34 using PCNSL, recognized galectin-3, which was upregulated on microglia/macrophages, astrocytes, and cerebral endothelial cells upon CNS invasion by PCNSL. Thus, PCNSL Ig may recognize CNS proteins as self-Ags. Their interaction may contribute to BCR signaling with sustained NF-κB activation and, ultimately, may foster tumor cell proliferation and survival. These data may also explain, at least in part, the affinity of PCNSL cells for the CNS., (Copyright © 2015 by The American Association of Immunologists, Inc.)

The management of primary CNS lymphoma is one of the most controversial topics in neuro-oncology because of the complexity of the disease and the very few controlled studies available. In 2013, the European Association of Neuro-Oncology created a multidisciplinary task force to establish evidence-based guidelines for immunocompetent adults with primary CNS lymphoma. In this Review, we present these guidelines, which provide consensus considerations and recommendations for diagnosis, assessment, staging, and treatment of primary CNS lymphoma. Specifically, we address aspects of care related to surgery, systemic and intrathecal chemotherapy, intensive chemotherapy with autologous stem-cell transplantation, radiotherapy, intraocular manifestations, and management of elderly patients. The guidelines should aid clinicians in their daily practice and decision making, and serve as a basis for future investigations in neuro-oncology., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Primary lymphoma of the central nervous system (PCNSL) is a diffuse large B-cell lymphoma confined to the CNS. It has been hypothesized that antigen(s) in the CNS may trigger tumor cell proliferation. Because efforts to identify potential antigens have been unsuccessful to date, we studied the B-cell receptor in detail in a comprehensive series of 50 PCNSLs to obtain indirect information on potential antigens. Potentially functional V-D-J rearrangements were identified in all PCNSLs analyzed. Immunoglobulin heavy-chain variable gene segment (IGHV), IGHV4, was the predominant family used by 66% (33 of 50) of PCNSLs with a preferential rearrangement of the IGHV4-34 gene segment (18 [55%] of 33). The IGHV genes showed mutation frequencies from 0% to 29%, with a high average mutation frequency of 10%. In addition to 48% (24 of 50) of PCNSLs being highly mutated, 22% (11 of 50) defined a low-level mutated group. Antigen selection of the tumor cells or their precursors was indicated by replacement/silent mutation ratios and ongoing somatic hypermutation. Complementarity determining region 3 length and composition as well as the lack of stereotyped B-cell receptors suggest involvement of several antigens instead of a unique antigen recognized by the tumor cells.

Primary lymphoma of the central nervous system is a distinct diffuse large B-cell lymphoma confined to the nervous system. Whereas classical cases can be classified easily, differential diagnosis can be a challenge in particular in patients who had received treatment prior to biopsy. In the differential diagnosis, other tumours and inflammatory diseases of autoimmune and infectious aetiology need to be considered., (Copyright © 2013 John Wiley & Sons, Ltd.)

Primary lymphoma of the central nervous system (CNS, PCNSL) is a specific diffuse large B cell lymphoma entity arising in and confined to the CNS. Despite extensive research since many decades, the pathogenetic mechanisms underlying the remarkable tropism of this peculiar malignant hematopoietic tumor remain still to be elucidated. In the present review, we summarize the present knowledge on the genotypic and phenotypic characteristics of the tumor cells of PCNSL, give an overview over deregulated molecular pathways in PCNSL and present recent progress in the field of preclinical modeling of PCNSL in mice. With regard to the phenotype, PCNSL cells resemble late germinal center exit IgM+IgD+ B cells with blocked terminal B cell differentiation. They show continued BCL6 activity in line with ongoing activity of the germinal center program. This together with the pathways deregulated by genetic alterations may foster B cell activation and brisk proliferation, which correlated with the simultaneous MYC and BCL2 overexpression characteristic for PCNSL. On the genetic level, PCNSL are characterized by ongoing aberrant somatic hypermutation that, besides the IG locus, targets the PAX5, TTF, MYC, and PIM1 genes. Moreover, PCNSL cells show impaired IG class switch due to sμ region deletions, and PRDM1 mutations. Several important pathways, i.e., the B cell receptor (BCR), the toll-like receptor, and the nuclear factor-κB pathway, are activated frequently due to genetic changes affecting genes like CD79B, SHIP, CBL, BLNK, CARD11, MALT1, BCL2, and MYD88. These changes likely foster tumor cell survival. Nevertheless, many of these features are also present in subsets of systemic DLBLC and might not be the only reasons for the peculiar tropism of PCNSL. Here, preclinical animal models that closely mimic the clinical course and neuropathology of human PCNSL may provide further insight and we discuss recent advances in this field. Such models enable us to understand the pathogenetic interaction between the malignant B cells, resident cell populations of the CNS, and the associated inflammatory infiltrate. Indeed, the immunophenotype of the CNS as well as tumor cell characteristics and intracerebral interactions may create a micromilieu particularly conducive to PCNSL that may foster aggressiveness of tumor cells and accelerate the fatal course of disease. Suitable animal models may also serve as a well-defined preclinical system and may provide a useful tool for developing new specific therapeutic strategies.

Lymphomas can arise within the central nervous system (CNS) as primary CNS lymphoma (PCNSL) typically involving the brain and less often the leptomeninges, eyes, and spinal cord. In contrast to PCNSL, secondary CNS lymphoma (SCNSL) is considered to originate as quasi metastasis from systemic lymphoma spreading to the CNS. Both types of CNS lymphomas are predominantly tumours of the diffuse large B-cell type and represent aggressive diseases necessitating a rapid diagnosis. Following neuroimaging based on magnetic resonance imaging, stereotaxy and histopathological diagnosis of CNS lymphoma currently remain obligatory to plan treatment. However, progress in cytopathological, immunophenotypic, and molecular genetic analyses of the cerebrospinal fluid (CSF) has been achieved recently and potentially will facilitate lymphoma diagnosis in the future. This review describes the diagnostic procedures in patients with suspected CNS lymphomas, primarily PCNSL. In addition to a summary of the standard diagnostic work-up, an overview and discussion of current data on different techniques for evaluation of the CSF in CNS lymphoma are given., (© 2011 Blackwell Publishing Ltd.)

The diagnosis of primary central nervous system lymphoma (PCNSL) depends on histopathology of brain biopsies, because disease markers in the cerebrospinal fluid (CSF) with sufficient diagnostic accuracy are not available yet. MicroRNAs (miRNAs) are regulatory RNA molecules that are deregulated in many disease types, including cancer. Recently, miRNAs have shown promise as markers for cancer diagnosis. In this study, we demonstrate that miRNAs are present in the CSF of patients with PCNSL. With a candidate approach and miRNA quantification by reverse transcription polymerase chain reaction, miRNAs with significant levels in the CSF of patients with PCNSL were identified. MiR-21, miR-19, and miR-92a levels in CSF collected from patients with PCNSL and from controls with inflammatory CNS disorders and other neurologic disorders indicated a significant diagnostic value of this method. Receiver-operating characteristic analyses showed area under the curves of 0.94, 0.98, and 0.97, respectively, for miR-21, miR-19, and miR-92a CSF levels in discriminating PCNSL from controls. More importantly, combined miRNA analyses resulted in an increased diagnostic accuracy with 95.7% sensitivity and 96.7% specificity. We also demonstrated a remarkable stability of miRNAs in the CSF. In conclusion, CSF miRNAs are potentially useful tools as novel noninvasive biomarker for the diagnosis of PCNSL.

Primary CNS lymphoma (PCNSL), the intracerebral subgroup of diffuse large B cell lymphoma (DLBCL), shows evidence for aberrant activation of the nuclear factor (NF)-kappaB pathway. In order to identify potential activators of the NF-kappaB complex, we analyzed the CARD11 and TNFAIP3 genes for the presence of somatic mutations and TNFAIP3 for aberrant promoter methylation in PCNSL. We also compared PCNSL to spinal DLBCL, because CARD11 and TNFAIP3 mutations have been described in systemic DLBCL. CARD11 mutations, located in the coiled-coil region, which may activate NF-kappaB, were detected in 16% (5/32) of PCNSL, while TNFAIP3 mutations were detected in 3% (1/32) of PCNSL. In PCNSL, all CARD11 mutations were heterozygous, in-frame, induced amino acid exchanges, and presumably led to activation of this oncogene. Spinal DLBCL harbored mutations of CARD11 and TNFAIP3 in 10% (1/10) and 20% (2/10) of cases, respectively. In both PCNSL and spinal DLBCL, mutations in CARD11 and TNFAIP3 were mutually exclusive. TNFAIP3 was unmethylated in all PCNSLs (30/30) and spinal DLBCLs (10/10). We conclude that mutations of the oncogene CARD11 may contribute to NF-kappaB activation and thereby play a role in the pathogenesis of PCNSL, while, in contrast to systemic DLBCL, inactivation of TNFAIP3 either by mutation or methylation seems to be of minor significance.

In primary central nervous system lymphoma (PCNSL), 2 international prognostic scores have been developed to estimate the outcome according to certain "prognostic groups". However, these scores do not predict the individual course of a single patient under therapy. In this analysis, we addressed the question of whether early tumor remission in patients still under therapy, according to magnetic resonance imaging (MRI) criteria, helps to predict long-term outcome. Eighty-eight patients treated with 6 polychemotherapy cycles within a pilot/phase II trial underwent MRI scanning within 72 hours prior to initiation of therapy, after the second chemotherapy cycle, and after completion of chemotherapy. Response was assessed by contrast-enhanced MRI of the brain according to the Macdonald criteria. Median follow-up was 42 months (range, 0-124 months). Patients achieving a complete radiographic response after 2 courses of chemotherapy (n = 18) had a significantly longer median overall survival (OS) (not reached) and median time-to-treatment failure (TTF) (not reached) than patients with complete response (CR) after termination of treatment but with only a partial response after the second cycle (n = 24) (OS: 55 months; TTF: 32 months) (P < .01). Early complete tumor response assessed by MRI after the second of sixth scheduled chemotherapy cycles was highly predictive for both OS and TTF in patients with PCNSL treated in this series.

Objective: To evaluate long-term progression-free survival and overall survival, quality of life, and cognitive function in primary central nervous system lymphoma after systemic and intraventricular chemotherapy without radiotherapy., Methods: A long-term follow-up was conducted on surviving primary central nervous system lymphoma patients having been enrolled in a pilot/phase II trial between September 1995 and December 2001. Initially, 65 patients (median age, 62 years) had been treated with systemic and intraventricular chemotherapy without radiotherapy. All living patients were contacted, and a neurological examination, comprehensive neuropsychological testing, quality-of-life assessment, and imaging were performed., Results: Twenty-one of all 65 patients (32 %) and 17 of 30 patients 60 years or younger (57%), respectively, were still alive at median follow-up of 100 months (range, 77-149 months). Nineteen of 21 patients completed all investigations; 1 was lost to follow-up. In three patients, an exclusively extraneural relapse of a high-grade non-Hodgkin's lymphoma was diagnosed after 9, 31, and 40 months, respectively. All of them experienced complete remission to high dose. Neither late neurotoxicity nor compromise of quality of life was found in any of the patients examined., Interpretation: Primary polychemotherapy based on high-dose methotrexate (MTX) and cytarabine (Ara-C) is highly efficient in treatment of primary central nervous system lymphoma. About half of patients 60 years or younger can obviously be cured with this regimen without long-term neurotoxic sequelae or quality-of-life compromise.

Background: Although primary lymphomas of the central nervous system (PCNSL) and extracerebral diffuse large B-cell lymphoma (DLBCL) cannot be distinguished histologically, it is still a matter of debate whether PCNSL differ from systemic DLBCL with respect to their molecular features and pathogenesis. Analysis of the DNA methylation pattern might provide further data distinguishing these entities at a molecular level., Methods: Using an array-based technology we have assessed the DNA methylation status of 1,505 individual CpG loci in five PCNSL and compared the results to DNA methylation profiles of 49 DLBCL and ten hematopoietic controls., Results: We identified 194 genes differentially methylated between PCNSL and normal controls. Interestingly, Polycomb target genes and genes with promoters showing a high CpG content were significantly enriched in the group of genes hypermethylated in PCNSL. However, PCNSL and systemic DLBCL did not differ in their methylation pattern., Conclusions: Based on the data presented here, PCNSL and DLBCL do not differ in their DNA methylation pattern. Thus, DNA methylation analysis does not support a separation of PCNSL and DLBCL into individual entities. However, PCNSL and DLBCL differ in their DNA methylation pattern from non- malignant controls.

Forkhead box P1 (FOXP1) protein is a transcription factor involved in cell signaling and regulation of gene expression. The overexpression of FOXP1 in a subgroup of systemic diffuse large B-cell lymphomas has been associated with an exceptionally poor clinical outcome. Data on FOXP1 expression in primary central nervous system lymphomas (PCNSL), that is, diffuse large B-cell lymphomas confined to the central nervous system, are not yet available. We analyzed 43 PCNSL from immunocompetent patients. Immunohistochemistry showed expression of FOXP1 protein in 21 (88%) of 24 cases. All 19 PCNSL analyzed by quantitative gene expression analysis showed overexpression of truncated FOXP1 Isoforms 3 and 9 and downregulation of normal-size FOXP1 compared with nonmalignant germinal center B cells, the normal counterpart of PCNSL tumor cells. Thus, truncated FOXP1 isoforms are preferentially overexpressed in PCNSL as they are in diffuse large B-cell lymphomas. Although the mechanisms are presently unclear, this overexpression may contribute to a poor prognosis in PCNSL.

Background: A systemic and intraventricular polychemotherapy regimen (the Bonn protocol) without radiotherapy resulted in durable responses in 75% of patients <60 years with primary CNS lymphoma (PCNSL), but was complicated by a high rate of Ommaya reservoir infections. Here, the efficacy and toxicity of this regimen without intraventricular treatment was evaluated in PCNSL., Patients and Methods: From August 2003 to November 2005, 18 patients with PCNSL <60 years (median age, 53 years) were treated in a phase II trial with a high-dose methotrexate (MTX; cycles 1, 2, 4 and 5) and cytarabine (Ara-C; cycles 3 and 6) based systemic therapy including dexamethasone, vinca-alkaloids, ifosfamide and cyclophosphamide., Results: Study accrual was prematurely stopped in November 2005 due to a high rate of early relapses. Seventeen of 18 patients were assessable for response: nine (53%) achieved complete response (CR), two (12%) complete response/unconfirmed (CRu) and two (12%) partial response (PR); four (24%) showed progressive disease (PD). One treatment was stopped due to toxicity. Median follow-up was 23 months, median response duration was only 10 months in responding patients, and median time to treatment failure (TTF) was 8 months in the whole group. Median overall survival (OS) has not been reached. Systemic toxicity was mainly hematologic., Conclusions: In PCNSL patients <60 years, polychemotherapy without intraventricular treatment results in a high response rate, but is associated with early relapses in the majority of cases. This is in contrast to the results achieved with the same protocol but with intraventricular treatment.

Primary lymphomas of the CNS (PCNSLs) show molecular features of the late germinal center exit B-cell phenotype and are impaired in their terminal differentiation as indicated by a lack of immunoglobulin class switching. Because the positive regulatory domain I protein with ZNF domain (PRDM1/BLIMP1) is a master regulator of terminal B-cell differentiation into plasma cells, we investigated a series of 21 PCNSLs for the presence of mutations in the PRDM1 gene and alterations in the expression pattern of the PRDM1 protein. Direct sequencing of all coding exons of the PRDM1 gene identified deleterious mutations associated with abrogation of PRDM1 protein expression in 4 of 21 (19%) PCNSLs. Thus, similar to systemic diffuse large B-cell lymphomas, PRDM1 may be a tumor suppressor in some PCNSL and contribute to lymphomagenesis by impairing terminal differentiation.

The expression pattern of a subset of chemokines and their corresponding receptors was investigated in primary central nervous system lymphomas (PCNSL). The tumor cells consistently expressed CXCR4, CXCL12, CXCR5, and CXCL13, both at mRNA and protein levels. Cerebral endothelial cells were positive for CXCL12 and CXCL13, while reactive astrocytes and microglial cells expressed CXCL12, CCR5, and CCR6. Inflammatory T cells in PCNSL were characterized by CCR5 and CCR6 positivity. Taken together, our data indicate a cell type-specific repertoire of chemokine and chemokine receptor expression in PCNSL suggesting that chemokine-mediated interactions facilitate crossing of the blood-brain barrier as well as intracerebral dissemination of PCNSL cells. In addition, chemokines expressed by tumor cells may contribute to induction of reactive glial changes and influence the composition of inflammatory infiltrates in PCNSL. Therefore, cell type specific expression of distinct chemokine profiles likely plays a role in the pathogenesis of PCNSL and may contribute to their characteristic histological appearance.

Recent studies point to a role of nuclear factor (NF)-kappaB signaling in a subset of diffuse large B cell lymphomas. We have analyzed the expression of 21 genes encoding NF-kappaB family members, upstream modulators, and targets in 32 primary central nervous system lymphomas (PCNSLs) by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Compared with nonmalignant germinal center centroblasts, expression of BCL10, REL, IAP1, and TRAF1 was significantly lower in PCNSLs, whereas that of BAX, BCLXL, BCL2, MALT1, CARD9, CARD10, CARD11, CARD14, CCND2, cFLIP, RELA, RELB, NFKB1, NFKB2, and IRF4 was higher. Hierarchical clustering of gene expression data revealed two distinct subgroups of PCNSLs, which were characterized by significantly different transcriptional levels, predominantly of BCL10, but also of REL and IAP1. Thus, these quantitative RT-PCR data with expression of genes of the NF-kappaB family as well as NF-kappaB-regulated genes together with immunohistochemical detection of nuclear RELA and REL indicate activation of the NF-kappaB pathway in PCNSLs, which may contribute to their high proliferative activity and the low level of apoptosis.

Primary lymphomas of the central nervous system (PCNSLs) were investigated for their capacity to perform further maturation steps. We studied a series of 11 PCNSLs derived from immunocompetent patients for immunoglobulin (Ig) class switch recombination (CSR) by performing reverse transcriptase-polymerase chain reaction (RT-PCR) for transcripts of Ig constant region gene segments (IGHC). This analysis revealed exclusive transcription of IgM and IgD mRNA in the absence of IgG, IgA, or IgE transcription. This finding was corroborated at the protein level by the immunohistochemical demonstration of IgM on the surface of the tumor cells. The unexpected lack of CSR may be due to internal switch mu region deletions, which were detected in 7 of 11 cases. We also found that expression of activation-induced cytidine deaminase (AID), which is required for CSR and somatic hypermutation, was detectable by RT-PCR in 4 of 10 cases and by immunohistochemistry in one of three cases analyzed. This may indicate that ongoing somatic mutation, which is often observed in PCNSL, could be due to sustained AID expression in a fraction of cases and that intraclonal V gene diversity may occur in other cases at an earlier phase of tumor clone expansion, when AID may have been expressed.

We have addressed whether aberrant ongoing hypermutation can be detected in the proto-oncogenes PIM1, c-MYC, RhoH/TTF, PAX5, and the tumor-suppressor gene CD95 in primary central nervous system lymphomas (PCNSLs) derived from immunocompetent HIV-negative patients. Nine of 10 PCNSLs analyzed harbored somatic mutations in the PIM1, c-MYC, RhoH/TTF, and PAX5 genes, but not in the CD95 gene, with 8 tumors carrying alterations in at least 2 of these genes. Furthermore, ongoing aberrant mutation was evidenced in a subset of PCNSLs (2 of 3). Although most of the mutations corresponded to base pair substitutions, deletions were also present. The mean mutation frequency was approximately 60-fold lower for these genes compared with the values obtained for immunoglobulin genes in PCNSL. They were increased 2- to 5-fold compared with extracerebral diffuse large B-cell lymphoma (DLBCL). In summary, our data demonstrate aberrant somatic hypermutations at high frequency in the PIM1, PAX5, RhoH/TTF, and c-MYC genes in most PCNSLs. These findings may indicate a pathogenic role for aberrant somatic hypermutation in PCNSL development. In contrast, although mutations were detected in exon 9 of the CD95 gene, the lack of mutations in the 5' region provides no evidence for the CD95 gene as a target for aberrant somatic mutation.

Purpose: To evaluate response rate, response duration, overall survival (OS), and toxicity in primary CNS lymphoma (PCNSL) after systemic and intraventricular chemotherapy with deferred radiotherapy., Patients and Methods: From September 1995 to July 2001, 65 consecutive patients with PCNSL (median age, 62 years) were enrolled onto a pilot and phase II study evaluating chemotherapy without radiotherapy. A high-dose methotrexate (MTX; cycles 1, 2, 4, and 5) and cytarabine (ARA-C; cycles 3 and 6)-based systemic therapy (including dexamethasone, vinca-alkaloids, ifosfamide, and cyclophosphamide) was combined with intraventricular MTX, prednisolone, and ARA-C., Results: Sixty-one of 65 patients were assessable for response. Of these, 37 patients (61%) achieved complete response, six (10%) achieved partial response, and 12 (19%) progressed under therapy. Six (9%) of 65 patients died because of treatment-related complications. Follow-up is 0 to 87 months (median, 26 months). The Kaplan-Meier estimates for median time to treatment failure (TTF) and median OS were 21 months and 50 months, respectively. For patients older than 60 years, median survival was 34 months, and the median TTF was 15 months. In patients younger than 61 years, median survival and median TTF have not been reached yet; the 5-year survival fraction is 75%. Systemic toxicity was mainly hematologic. Ommaya reservoir infection occurred in 12 patients (19%), and permanent cognitive dysfunction possibly as a result of treatment occurred in only two patients (3%)., Conclusion: Primary chemotherapy based on high-dose MTX and ARA-C is highly efficient in PCNSL. Response rate and response duration in this series are comparable to the response rates and durations reported after combined radiotherapy and chemotherapy. Neurotoxicity was infrequent.

Primary central nervous system lymphomas (PCNSL) constitute diffuse large B-cell lymphomas arising in and remaining confined to the brain. Little information is available on cytogenetic changes in PCNSL, and recurrent chromosomal translocations have not yet been identified. Fluorescence in situ hybridization (FISH) of a series of 13 PCNSL from immunocompetent patients revealed 3 cases with signal patterns of a BCL6-specific probe suggesting a breakpoint in this oncogene locus in chromosome band 3q27. Here, we describe cloning of the translocation breakpoints by long-distance inverse polymerase chain reaction (LDI-PCR) in 2 of these tumors. Both breakpoints affected the first intron of BCL6. In one PCNSL, the HSPCA (HSP90A) gene in 14q32.31 was identified as BCL6 partner. In the second lymphoma, the gene encoding glyceraldehyde-3-phosphate dehydrogenase (GAPD) on 12p13.31 was detected as a hitherto unknown partner of BCL6. Our results suggest translocation-mediated BCL6 oncogene activation as a so far unknown pathogenetically relevant mechanism in PCNSL.

The prospective multicenter NOA-03 trial, conducted by the Neuro-Oncology Working Group (NOA) of the German Cancer Society, was initiated to define the feasibility and efficacy of single-agent high-dose methotrexate therapy without concomitant radiotherapy in immunocompetent patients with primary central nervous system lymphoma. Thirty-seven patients (median age, 60 years) received 179 biweekly courses of 8 g/m2 methotrexate. Response was assessed after 3 and 6 courses. We had planned to enter 105 patients into the trial. Since fewer than the projected 18 of 37 patients achieved a complete response after an intermediate analysis, the trial was closed. In intention-to-treat analysis, 11 of 37 patients (29.7%) achieved complete response, whereas 14 of 37 patients (37.8%) were found to have progressive disease. The median relapse-free survival among complete response patients was 13.7 months. Multivariate logistic regression analysis revealed that corticosteroid application during the first methotrexate course was associated with complete response. The regimen was well tolerated, but, unlike previously reported results, the activity of high-dose methotrexate was only moderate.