The Combined Performance of ADC, CSF CXC Chemokine Ligand 13, and CSF Interleukin 10 in the Diagnosis of Central Nervous System Lymphoma

Logistic regression modeling of cytokines for cerebrospinal fluid evaluation in primary central nervous system lymphoma

BACKGROUND

The diagnostic utility of cerebrospinal fluid (CSF) cytology encounters impediments stemming from variability in cell collection techniques and pathologists' morphological acumen, resulting in wide-ranging CSF positivity rates for primary central nervous system lymphomas (PCNSL). Such disparity impacts patient evaluation, treatment stratagem, and prognostication. Thus, this study endeavors to explore liquid biomarkers complementary to CSF cytology or immunophenotype analysis in the diagnosis of CSF involvement.

METHODS

398 newly diagnosed PCNSL patients were categorized into CSF involvement and non-involvement groups based on CSF cytology and immunophenotype analysis. Binary logistic regression analysis was performed on 338 patients to investigate factors predicting CSF involvement and to develop a joint prediction model. An additional cohort of 60 PCNSL patients was recruited for model validation. Statistical analyses included the Mann-Whitney U test for comparing various CSF parameters between two groups. ROC curve analyses were performed for each biomarker to identify PCNSL CSF involvement.

RESULTS

The cytokine IL-10 level in CSF has emerged as the most promising biomarker for CSF evaluation, boasting an ROC AUC of 0.922. C-TNFα and soluble C-IL2R demonstrate efficacy in quantifying tumor burden within the CSF. Logistic regression identified C-IL10lg (OR = 30.103, P < 0.001), C-TNC (OR = 1.126, P < 0.001), C-IL2Rlg (OR = 3.743, P = 0.029) as independent predictors for CSF involvement, contributing to a joint predictive model with an AUC of 0.935, sensitivity of 74.1 %, and specificity of 93.0 %. Validation of the model in an independent cohort confirmed its effectiveness, achieving an AUC of 0.9713.

CONCLUSIONS

The identification of these feasible biomarkers and the development of an accurate prediction model may facilitate the precise evaluation of CSF status in PCNSL, offering significant advancements in patient management.

Molecular diagnosis of primary CNS lymphoma in 2024 using MYD88Leu265Pro and IL-10

Early diagnosis is crucial for the successful treatment of primary CNS lymphoma (PCNSL), a rapidly progressing tumour. Suspicion raised on brain MRI must be confirmed by a histopathological diagnosis of a tumour specimen collected by stereotactic biopsy. In rare cases, cerebrospinal fluid (CSF) or vitreous humour might aid in providing a cytological diagnosis. Several disease-related, patient-related, and treatment-related factors affect the timing and accuracy of diagnosis and patient outcome. Some molecules detected in CSF, aqueous and vitreous humour, and peripheral blood were proposed as diagnostic biomarkers for PCNSL; however, detection methods for most of these molecules are not yet standardised, have a long turnaround time, are expensive, and have little reproducibility among labs. By contrast, the MYD88Leu265Pro somatic hotspot mutation, revealed by PCR-based assay, is currently and reliably used during the diagnosis of some lymphomas, and IL-10, measured by enzyme-linked immunosorbent assay, is routinely used to diagnose and monitor different common metabolic and immunological diseases. Several independent studies have shown that MYD88Leu265Pro and IL-10 can be easily assessed in peripheral blood, plasma, aqueous and vitreous humour, and CSF of patients with PCNSL with substantial sensitivity and specificity, especially when evaluated in combination. In this Viewpoint, evidence supporting the routine use of MYD88Leu265Pro and IL-10 in diagnosing PCNSL is considered, and some examples of the frequent difficulties found in the diagnosis of PCNSL are provided, highlighting the role and indications of these two biomarkers to improve the timely recognition of this aggressive tumour.

Liquid biopsy for improving diagnosis and monitoring of CNS lymphomas: A RANO review

BACKGROUND

The utility of liquid biopsies is well documented in several extracranial and intracranial (brain/leptomeningeal metastases, gliomas) tumors.

METHODS

The RANO (Response Assessment in Neuro-Oncology) group has set up a multidisciplinary Task Force to critically review the role of blood and cerebrospinal fluid (CSF)-liquid biopsy in CNS lymphomas, with a main focus on primary central nervous system lymphomas (PCNSL).

RESULTS

Several clinical applications are suggested: diagnosis of PCNSL in critical settings (elderly or frail patients, deep locations, and steroid responsiveness), definition of minimal residual disease, early indication of tumor response or relapse following treatments, and prediction of outcome.

CONCLUSIONS

Thus far, no clinically validated circulating biomarkers for managing both primary and secondary CNS lymphomas exist. There is need of standardization of biofluid collection, choice of analytes, and type of technique to perform the molecular analysis. The various assays should be evaluated through well-organized central testing within clinical trials.

Intrathecal IgM synthesis as a diagnostic marker in patients with suspected CNS lymphoma

For CNS lymphomas (CNSL), there is a high need for minimally invasive and easily obtainable diagnostic markers. Intrathecal IgM synthesis can easily be determined in routine CSF diagnostics. The aim of this study was to systematically investigate the diagnostic potential of intrathecal IgM synthesis in primary and secondary CNSL (PCNSL and SCNSL). In this retrospective study, patients with a biopsy-proven diagnosis of PCNSL or SCNSL were compared with patients with other neurological diseases in whom CNSL was initially the primary radiological differential diagnosis based on MRI. Sensitivity and specificity of intrathecal IgM synthesis were calculated using receiver operating characteristic curves. Seventy patients with CNSL were included (49 PCNSL and 21 SCNSL) and compared to 70 control patients. The sensitivity and specificity for the diagnosis of CNSL were 49% and 87%, respectively, for the entire patient population and 66% and 91% after selection for cases with tumor access to the CSF system and isolated intrathecal IgM synthesis. In cases with MRI-based radiological suspicion of CNSL, intrathecal IgM synthesis has good specificity but limited sensitivity. Because of its low-threshold availability, analysis of intrathecal IgM synthesis has the potential to lead to higher diagnostic accuracy, especially in resource-limited settings, and deserves further study.

Systematic Review of Cerebrospinal Fluid Biomarker Discovery in Neuro-Oncology: A Roadmap to Standardization and Clinical Application

Effective diagnosis, prognostication, and management of CNS malignancies traditionally involves invasive brain biopsies that pose significant risk to the patient. Sampling and molecular profiling of cerebrospinal fluid (CSF) is a safer, rapid, and noninvasive alternative that offers a snapshot of the intracranial milieu while overcoming the challenge of sampling error that plagues conventional brain biopsy. Although numerous biomarkers have been identified, translational challenges remain, and standardization of protocols is necessary. Here, we systematically reviewed 141 studies (Medline, SCOPUS, and Biosis databases; between January 2000 and September 29, 2022) that molecularly profiled CSF from adults with brain malignancies including glioma, brain metastasis, and primary and secondary CNS lymphomas. We provide an overview of promising CSF biomarkers, propose CSF reporting guidelines, and discuss the various considerations that go into biomarker discovery, including the influence of blood-brain barrier disruption, cell of origin, and site of CSF acquisition (eg, lumbar and ventricular). We also performed a meta-analysis of proteomic data sets, identifying biomarkers in CNS malignancies and establishing a resource for the research community.

CXCL13 in Cerebrospinal Fluid: Clinical Value in a Large Cross-Sectional Study

C-X-C-motif chemokine ligand 13 (CXCL13) in cerebrospinal fluid (CSF) is increasingly used in clinical routines, although its diagnostic specificity and divergent cut-off values have been defined so far mainly for neuroborreliosis. Our aim was to evaluate the value of CSF-CXCL13 as a diagnostic and treatment response marker and its role as an activity marker in a larger disease spectrum, including neuroborreliosis and other neuroinflammatory and malignant CNS-disorders. Patients who received a diagnostic lumbar puncture (LP) (n = 1234) between July 2009 and January 2023 were included in our retrospective cross-sectional study. The diagnostic performance of CSF-CXCL13 for acute neuroborreliosis was highest at a cut-off of 428.92 pg/mL (sensitivity: 92.1%; specificity: 96.5%). In addition, CXCL13 levels in CSF were significantly elevated in multiple sclerosis with clinical (p = 0.001) and radiographic disease activity (p < 0.001). The clinical utility of CSF-CXCL13 appears to be multifaceted. CSF-CXCL13 is significantly elevated in patients with neuroborreliosis and shows a rapid and sharp decline with antibiotic therapy, but it is not specific for this disease and is also highly elevated in less common subacute neuroinfectious diseases, such as neurosyphilis and cryptococcal meningitis or in primary/secondary B-cell lymphoma.

Role and application of chemokine CXCL13 in central nervous system lymphoma

Chemokine ligand 13 (CXCL13) and its chemokine receptor 5 (CXCR5) both play significant roles in the tumor microenvironment (TME). CXCL13 in cerebrospinal fluid (CSF) has recently been found to have significant diagnostic and prognostic value in primary and secondary central nervous system (CNS) diffuse large B-cell lymphoma (DLBCL), and the CXCL13-CXCR5 axis has been shown to play an important chemotactic role in the TME of CNS-DLBCL. In this review, we first describe the clinical value of CXCL13 in CSF as a prognostic and diagnostic biomarker for CNS-DLBCL. In addition, this review also discusses the specific mechanisms associated with the CXCL13-CXCR5 axis in tumor immunity of primary diffuse large B cell lymphoma of the central nervous system (PCNS-DLBCL) by reviewing the specific mechanisms of this axis in the immune microenvironment of DLBCL and CNS inflammation, as well as the prospects for the use of CXCL13-CXCR5 axis in immunotherapy in PCNS-DLBCL.

Challenges in the management of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare extranodal non-Hodgkin lymphoma. Stereotactic biopsy remains the gold standard for the pathological diagnosis of PCNSL. However, certain new auxiliary diagnostic methods are considered to have good application prospects; these include cytokine and tumor circulating DNA, among others. Although new drugs such as immunomodulators, immune checkpoint inhibitors, chimeric antigen receptor T-cells, and Bruton tyrosine kinase inhibitors have brought hope owing to their improved efficacy, the high recurrence rate and subsequent high mortality remain barriers to long-term survival. Increasing emphasis is therefore being placed on consolidation treatments. Consolidation treatment strategies include whole brain radiotherapy, autologous hematopoietic stem cell transplantation, and non-myeloablative chemotherapy. As studies directly comparing the effectiveness and safety of different consolidation treatment schemes are lacking, the optimal consolidation strategy remains uncertain. This article will review the diagnosis and treatment of PCNSL, focusing on the progress in research pertaining to consolidation therapy.

Recent advances in the diagnosis and the treatment of primary CNS lymphoma

This review focuses on the recent progress in the management of primary central nervous system lymphoma (PCNSL). Multiomic analyses allowed to better understand the tumorigenesis of PCNSL and to establish a molecular classification with prognostic value that will optimize patient management and guide future targeted approaches. Cooperative clinical trials have demonstrated the feasibility and efficacy, in selected fit patients, of high-dose chemotherapy with autologous stem cell transplantation as post-induction consolidation, that will progressively replace whole brain radiotherapy associated with a much higher risk of delayed neurotoxicity. Several novel treatments have shown efficacy and overall good tolerance in PCNSL patients, such as Bruton's tyrosine kinase (BTK) inhibitors, imids, immune checkpoint inhibitors and chimeric antigen receptor T-cells (CAR-T). This opens promising therapeutic perspectives to improve the current standard treatment, especially for elderly and unfit patients who represent a growing population.

CSF biomarkers in primary CNS lymphoma

PCNSL is a non-Hodgkin lymphoma (NHL) affecting brain, spinal cord, eyes and leptomeninges. In the past two decades, its prognosis significantly improved due to therapeutic advances but it remains a highly aggressive tumor and early diagnosis is necessary for optimal management. Diagnosis relies on the identification of lymphoma cells in brain tissue obtained by stereotactic biopsy. Alternatively, lymphoma cells may be found in CSF through lumbar puncture (LP) or by a vitrectomy. For several reasons, the diagnosis of PCNSL may be challenging. Misleading radiological presentations are frequent. Dramatic response to steroids may bias histological analysis and deep brain location or frail health status can contraindicate brain biopsy. In the follow-up of patients who have been previously treated, differential diagnosis between tumor relapse and post-treatment may be also difficult. Therefore, the development of complementary reliable diagnostic tools is needed. This review will summarize several diagnostic or prognostic CSF biomarkers which have been proposed in PCNSL, their interests and limits.

Progress of radiological‑pathological workflows in the differential diagnosis between primary central nervous system lymphoma and high‑grade glioma (Review)

Primary central nervous system lymphoma (PCNSL) and high‑grade glioma (HGG) are distinct entities of the CNS with completely distinct treatments. The treatment of PCNSL is chemotherapy‑based, while surgery is the first choice for HGG. However, the clinical features of the two entities often overlap, and a clear pathological diagnosis is important for subsequent management, especially for the management of PCNSL. Stereotactic biopsy is recognized as one of the minimally invasive alternatives for evaluating the involvement of the CNS. However, in the case of limited tissue materials, the differential diagnosis between the two entities is still difficult. In addition, some patients are too ill to tolerate a needle biopsy. Therefore, combining imaging, histopathology and laboratory examinations is essential in order to make a clear diagnosis as soon as possible. The present study reviews the progress of comparative research on both imaging and laboratory tests based on the pathophysiological changes of the two entities, and proposes an integrative and optimized diagnostic process, with the purpose of building a better understanding for neurologists, hematologists, radiologists and pathologists.

Consensus recommendations for MRI and PET imaging of primary central nervous system lymphoma: guideline statement from the International Primary CNS Lymphoma Collaborative Group (IPCG)

Advanced molecular and pathophysiologic characterization of primary central nervous system lymphoma (PCNSL) has revealed insights into promising targeted therapeutic approaches. Medical imaging plays a fundamental role in PCNSL diagnosis, staging, and response assessment. Institutional imaging variation and inconsistent clinical trial reporting diminishes the reliability and reproducibility of clinical response assessment. In this context, we aimed to: (1) critically review the use of advanced positron emission tomography (PET) and magnetic resonance imaging (MRI) in the setting of PCNSL; (2) provide results from an international survey of clinical sites describing the current practices for routine and advanced imaging, and (3) provide biologically based recommendations from the International PCNSL Collaborative Group (IPCG) on adaptation of standardized imaging practices. The IPCG provides PET and MRI consensus recommendations built upon previous recommendations for standardized brain tumor imaging protocols (BTIP) in primary and metastatic disease. A biologically integrated approach is provided to addresses the unique challenges associated with the imaging assessment of PCNSL. Detailed imaging parameters facilitate the adoption of these recommendations by researchers and clinicians. To enhance clinical feasibility, we have developed both “ideal” and “minimum standard” protocols at 3T and 1.5T MR systems that will facilitate widespread adoption.

Liquid Biopsy and Other Non-Invasive Diagnostic Measures in PCNSL

Simple Summary

Primary central nervous system lymphoma (PCNSL) is an uncommon disease accounting for around 3% of primary CNS tumors. PCNSL exhibits aggressive clinical behavior and has an overall poor prognosis. The clinical presentation is variable, and there are no specific symptoms. Despite progress in radiographic neuroimaging, stereotactic brain biopsy remains obligatory for definitive diagnosis. Advanced standard diagnostics, including CSF cytology and flow cytometry, have limited sensitivity. Accordingly, there is an urgent need to improve the diagnostic tools for PCNSL, including novel non-invasive procedures. The aim of this review is to present and discuss modern methods that have the potential to contribute standard clinical diagnostics within the next few years.

Abstract

Primary central nervous system lymphoma is a rare but highly aggressive form of non-Hodgkin lymphoma that remains confined to the CNS neuroaxis. The diagnosis of PCNSL requires a high level of suspicion as clinical presentation varies depending on the involved CNS areas. Neurological symptoms and MRI findings may mimic gliomas, demyelinating lesions, or infectious and granulomatous diseases. Almost all PCNSL patients undergo invasive surgical procedures for definite diagnosis. Stereotactic biopsy is still the gold standard in achieving a diagnostic accuracy of 73–97%. Both the potential procedural morbidity and mortality, as well as the time to definite histopathologic diagnosis resulting in delays of treatment initiation, have to be considered. On the contrary, minimally invasive procedures, such as MRI, CSF cytology, and flow cytometry, still have limited value due to inferior specificity and sensitivity. Hence, novel diagnostic approaches, including mutation analyses (MYD88) in circulating tumor DNA (ctDNA) and the determination of microRNAs (miR-21, miR-19b, and miR-92) as well as cytokine levels (IL10 and IL6) in blood, cerebrospinal fluid (CSF), and vitreous fluid (VRF), move into the focus of investigation to facilitate the diagnosis of PCNSL. In this review, we outline the most promising approaches that are currently under clinical consideration.

CXCL13 and CXCL9 CSF Levels in Central Nervous System Lymphoma-Diagnostic, Therapeutic, and Prognostic Relevance

Background: Diagnostic delay and neurologic deterioration are still a problem for the treatment of rapidly progressing CNS lymphoma (CNSL); there is an unmet need for a diagnostic test with a high diagnostic yield and limited risk, minimizing the time to the initiation of effective treatment.

Methods: In this prospective monocentric study, we analyzed the utility of CXCL13 and CXCL9 as diagnostic, therapeutic and prognostic biomarkers for CNSL. Cerebrospinal fluid (CSF) from 155 consecutive patients admitted with brain lesions of various origins was collected. Levels of CXCL13 and CXCL9 were analyzed by ELISA. Additionally, CSF was analyzed during CNSL disease course (relapse, remission, progress) in 17 patients.

Results: CXCL13 and CXCL9 CSF levels were significantly increased in patients with CNSL compared to control patients with lesions of other origin. Using logistic regression and a minimal-p-value approach, a cut-off value of 80 pg/ml for CXCL13 shows high sensitivity (90.7%) and specificity (90.1%) for the diagnosis of active CNSL. CXCL9 at a cut-off value of 84 pg/ml is less sensitive (61.5%) and specific (87.1%). Both cytokines correlate with the clinical course and response to therapy.

Conclusions: Our results confirm the excellent diagnostic potential of CXCL13 and introduce CXCL9 as a novel albeit less powerful marker for PCNSL.

MYD88 L265P mutation and interleukin-10 detection in cerebrospinal fluid are highly specific discriminating markers in patients with primary central nervous system lymphoma: results from a prospective study

Reliable biomarkers are needed to avoid diagnostic delay and its devastating effects in patients with primary central nervous system (CNS) lymphoma (PCNSL). We analysed the discriminating sensitivity and specificity of myeloid differentiation primary response (88) (MYD88) L265P mutation (mut-MYD88) and interleukin-10 (IL-10) in cerebrospinal fluid (CSF) of both patients with newly diagnosed (n = 36) and relapsed (n = 27) PCNSL and 162 controls (118 CNS disorders and 44 extra-CNS lymphomas). The concordance of MYD88 mutational status between tumour tissue and CSF sample and the source of ILs in PCNSL tissues were also investigated. Mut-MYD88 was assessed by TaqMan-based polymerase chain reaction. IL-6 and IL-10 messenger RNA (mRNA) was assessed on PCNSL biopsies using RNAscope technology. IL levels in CSF were assessed by enzyme-linked immunosorbent assay. Mut-MYD88 was detected in 15/17 (88%) PCNSL biopsies, with an 82% concordance in paired tissue-CSF samples. IL-10 mRNA was detected in lymphomatous B cells in most PCNSL; expression of IL-6 transcripts was negligible. In CSF samples, mut-MYD88 and high IL-10 levels were detected, respectively, in 72% and 88% of patients with newly diagnosed PCNSL and in 1% of controls; conversely, IL-6 showed a low discriminating sensitivity and specificity. Combined analysis of MYD88 and IL-10 exhibits a sensitivity and specificity to distinguish PCNSL of 94% and 98% respectively. Similar figures were recorded in patients with relapsed PCNSL. In conclusion, high detection rates of mut-MYD88 and IL-10 in CSF reflect, respectively, the MYD88 mutational status and synthesis of this IL in PCNSL tissue. These biomarkers exhibit a very high sensitivity and specificity in detecting PCNSL both at initial diagnosis and relapse. Implications of these findings in patients with lesions unsuitable for biopsy deserve to be investigated.

Clinical significance of interleukin-10 concentration in the cerebrospinal fluid of patients with primary central nervous system lymphoma

The diagnostic and prognostic evaluation of primary central nervous system lymphoma (PCNSL) is challenging due to the lack of sensitive biomarkers. The present study aimed to evaluate the value of interleukin (IL)-10 in this context. Between October 2016 and December 2018, 91 patients with suspected intracranial neoplasms were recruited, and the concentrations of IL-10 or IL-6 in both the cerebrospinal fluid (CSF) and blood were measured and analyzed by the Kruskal-Wallis test. The correlation between CSF IL-6 or IL-10 levels and tumor size was determined by Spearman's coefficient analysis. The receiver operating characteristic curve was used to evaluate the diagnostic value of CSF IL-6 and IL-10 levels. Median progression-free survival (PFS) and overall survival time were calculated using Kaplan-Meier survival analysis. Among the 91 patients, 3 were diagnosed with PCNSL on the basis of neuroimaging data and CSF IL-10 levels. A total of 35 cases were verified to show diffuse large B-cell lymphoma on histological assessment, 17 of which were diagnosed as PCNSL by MRI. The median PFS and OS were 8.00 months [95% confidence interval (CI), 3.94-12.06) and 17.5 months (95% CI, 11.55-23.45) respectively in the 12 PNCSL cases with regular follow up. The diagnostic efficiency of serum IL-6 levels was lower than that of serum IL-10 levels (P=0.030), which, in turn, was lower than that of CSF IL-10 levels (P<0.001). The decline and increase in CSF IL-10 levels was concurrent with improvement and deterioration in manifestation, respectively, which predated the MRI variation. High CSF IL-10 levels indicated low Karnofsky performance scale scores and shortened PFS times. CSF IL-10 levels higher than 1,000 pg/ml signified disease progression. CSF IL-10 levels could be a sensitive biomarker guiding the differential diagnosis, early recurrence detection, prognostic evaluation and therapeutic strategy establishment in cases of PCNSL.

High Level of IL-10 in Cerebrospinal Fluid is Specific for Diagnosis of Primary Central Nervous System Lymphoma

Purpose

The pathological diagnosis of primary central nervous system lymphoma (PCNSL) by stereotactic brain biopsy and craniotomy is not often applicable due to the high cost and associated complications. In recent years, some biomarkers in cerebrospinal fluid (CSF), including interleukin 10 (IL-10), microRNAs, CXC chemokine ligand 13 (CXCL13), have been reported to be associated with PCNSL. However, this conclusion was controversial. Therefore, this study was to test whether Th17 cell-related cytokines could be used to distinguish PCNSL from other brain tumors.

Patients and Methods

Th17 cell-related cytokines in CSF were measured in 108 patients with intracranial tumors, which included 66 PCNSL patients and 42 patients with other types of brain tumors. A receiver-operating characteristic (ROC) curve was utilized to analyze the diagnostic value of the cytokines based on the area under the curve (AUC).

Results

The CSF IL-10 level and IL-10/IL-6 ratios were significantly higher in PCNSL than in the other brain tumors (58.2 pg/mL VS 1.5 pg/mL, p=0.001; 24.3 VS 0.6, p=0.001). When the cutoff level of IL-10 was set at 8.3 pg/mL, its sensitivity and specificity for diagnosing PCNSL were 59.0% and 98%, respectively. The CSF IL-10 levels over 5pg/mL (+LR 12.3) were of significant value for the diagnosis of PCNSL. These parameters are highly valuable in PCNSL diagnosis, but their sensitivity is less valuable. The sensitivity of IL-4 and IL-17A, the ratio of mature lymphocytes and the monocytes/macrophages ratio in CSF were relatively high. In combination, the sensitivity increased by 15% and the specificity remained above 85%. The best combination was IL-10 and IL-17A, whose sensitivity was 70% and specificity was 96%.

Conclusion

The CSF level of IL-10 is a useful diagnostic biomarker in patients with PCNSL. The CSF levels of IL-4, IL-17A, mature lymphocytes and monocytes/macrophages can be used to increase the diagnostic value of CSF IL-10 level and IL-10/IL-6 ratio.

Molecular profiling of primary central nervous system lymphomas - predictive and prognostic value?

PURPOSE OF REVIEW

Primary central nervous system lymphoma (PCNSL) is a rare but aggressive variant of non-Hodgkin lymphoma. The diagnostic gold standard remains the pathologic review of tumor tissue mainly collected though biopsies. The majority of PCNSL are diffuse large B cell lymphoma (DLBCL). Biopsies are invasive procedures, and there have been efforts to develop minimally invasive diagnostic testing using serum and cerebral spinal fluid. This article reviews multiple markers that could potentially serve as future diagnostic tools and predictors of treatment response.

RECENT FINDINGS

Many studies have attempted to classify DLBCL into different subtypes for prognostic purposes using methods such as immunohistochemistry. PCNSL often falls under the activated B-cell-like subgroup, and further genomic sequencing has identified alterations in genes within the B-cell receptor signaling axis at increased frequencies. Two such genes, MYD88 and CD79B, implicate the involvement of the NF-kB (nuclear factor kappa-light-chain enhancer of activated B cells) pathway, and targeted agents to this pathway are currently being used in the treatment of relapsed/refractory PCNSL.

SUMMARY

Although recent genomic profiling of PCNSL has increased the understanding of drivers in this disease and has also led to the introduction of targeted inhibitors, these markers have not yet been used for diagnostic and/or prognostic purposes. Further studies will need to evaluate if they hold great diagnostic potential.

Multi-marker algorithms based on CXCL13, IL-10, sIL-2 receptor, and β2-microglobulin in cerebrospinal fluid to diagnose CNS lymphoma

Tumor biopsy is essential for the definitive diagnosis of central nervous system (CNS) lymphoma. However, the biopsy procedure carries the risk of complications such as bleeding, convulsions, and infection. Cerebrospinal fluid (CSF) β2‐microglobulin (β2‐MG), soluble IL‐2 receptor (sIL‐2R), and interleukin‐10 (IL‐10) are known to be useful diagnostic biomarkers for CNS lymphoma. The C‐X‐C motif chemokine ligand 13 (CXCL13) was recently reported to be another useful biomarker for CNS lymphoma. The purpose of this study is to establish a diagnostic algorithm that can avoid biopsy by combining these diagnostic biomarkers. In the first, we conducted a case‐control study (n = 248) demonstrating that the CSF CXCL13 concentration was significantly increased in CNS lymphoma patients compared with various other brain diseases (AUC = 0.981). We established a multi‐marker diagnostic model using CSF CXCL13, IL‐10, β2‐MG, and sIL‐2R from the results of the case‐control study and then applied the model to a prospective study (n = 104) to evaluate its utility. The multi‐marker diagnostic algorithms had excellent diagnostic performance: the sensitivity, specificity, positive predictive value, and negative predictive value were 97%, 97%, 94%, and 99%, respectively. In addition, CSF CXCL13 was a prognostic biomarker for CNS lymphoma patients. Our study suggests that multi‐marker algorithms are important diagnostic tools for patients with CNS lymphoma.

Diagnostic markers for CNS lymphoma in blood and cerebrospinal fluid: a systematic review

Diagnosing central nervous system (CNS) lymphoma remains a challenge. Most patients have to undergo brain biopsy to obtain tissue for diagnosis, with associated risks of serious complications. Diagnostic markers in blood or cerebrospinal fluid (CSF) could facilitate early diagnosis with low complication rates. We performed a systematic literature search for studies on markers in blood or cerebrospinal fluid for the diagnosis CNS lymphoma and assessed the methodological quality of studies with the Quality Assessment of Diagnostic Accuracy Studies tool (QUADAS‐2). We evaluated diagnostic value of the markers at a given threshold, as well as differences between mean or median levels in patients versus control groups. Twenty‐five studies were included, reporting diagnostic value for 18 markers in CSF (microRNAs ‐21, ‐19b, and ‐92a, RNU2‐1f, CXCL13, interleukins ‐6, ‐8, and ‐10, soluble interleukin‐2‐receptor, soluble CD19, soluble CD27, tumour necrosis factor‐alfa, beta‐2‐microglobulin, antithrombin III, soluble transmembrane activator and calcium modulator and cyclophilin ligand interactor, soluble B cell maturation antigen, neopterin and osteopontin) and three markers in blood (microRNA‐21 soluble CD27, and beta‐2‐microglobulin). All studies were at considerable risk of bias and there were concerns regarding the applicability of 15 studies. CXCL‐13, beta‐2‐microglobulin and neopterin have the highest potential in diagnosing CNS lymphoma, but further study is still needed before they can be used in clinical practice.

Therapy of primary CNS lymphoma: role of intensity, radiation, and novel agents

Primary central nervous system (CNS) lymphomas represent a subgroup of malignancies with specific characteristics, an aggressive course, and unsatisfactory outcome in contrast with other lymphomas comparable for tumor burden and histological type. Despite the high sensitivity to conventional chemotherapy and radiotherapy, remissions are frequently short lasting. Treatment efficacy is limited by several factors, including the biology and microenvironment of this malignancy and the "protective" effect of the blood-brain barrier, which limits the access of most drugs to the CNS. Patients who survive are at high risk of developing treatment-related toxicity, mainly disabling neurotoxicity, raising the question of how to balance therapy intensification with the control of side effects. Recent therapeutic progress and effective international cooperation have resulted in a significantly improved outcome over the past 2 decades, with a higher proportion of patients receiving treatment with curative intent. Actual front-line therapy consists of high-dose methotrexate-based polychemotherapy. Evidence supporting the addition of an alkylating agent and rituximab is growing, and a recent randomized trial demonstrated that the combination of methotrexate, cytarabine, thiotepa, and rituximab (MATRix regimen) is associated with a significantly better overall survival. Whole-brain irradiation and high-dose chemotherapy supported by autologous stem cell transplantation are 2 effective consolidation strategies in patients with a disease responsive to induction chemotherapy. Different strategies such as alkylating maintenance, conservative radiotherapy, and nonmyeloablative consolidation are being addressed in large randomized trials and a more accurate knowledge of the molecular and biological characteristics of this malignancy are leading to the development of target therapies in refractory/relapsing patients, with the overall aim to incorporate new active agents as part of first-line treatment. The pros and cons of these approaches together with the best candidates for each therapy are outlined in this article.

The Challenge of Primary Central Nervous System Lymphoma

Primary central nervous system (CNS) lymphoma is a challenging subtypes of aggressive non-Hodgkin lymphoma. Emerging clinical data suggest that optimized outcomes are achieved with dose-intensive CNS-penetrant chemotherapy and avoiding whole brain radiotherapy. Anti-CD20 antibody-based immunotherapy as a component of high-dose methotrexate-based induction programs may contribute to improved outcomes. An accumulation of insights into the molecular and cellular basis of disease pathogenesis is providing a foundation for the generation of molecular tools to facilitate diagnosis as well as a roadmap for integration of targeted therapy within the developing therapeutic armamentarium for this challenging brain tumor.

Diffusion-Weighted MRI Reflects Proliferative Activity in Primary CNS Lymphoma

Purpose

To investigate if apparent diffusion coefficient (ADC) values within primary central nervous system lymphoma correlate with cellularity and proliferative activity in corresponding histological samples.

Materials and Methods

Echo-planar diffusion-weighted magnetic resonance images obtained from 21 patients with primary central nervous system lymphoma were reviewed retrospectively. Regions of interest were drawn on ADC maps corresponding to the contrast enhancing parts of the tumors. Biopsies from all 21 patients were histologically analyzed. Nuclei count, total nuclei area and average nuclei area were measured. The proliferation index was estimated as Ki-67 positive nuclei divided by total number of nuclei. Correlations of ADC values and histopathologic parameters were determined statistically.

Results

Ki-67 staining revealed a statistically significant correlation with ADCmin (r = -0.454, p = 0.038), ADCmean (r = -0.546, p = 0.010) and ADCmax (r = -0.515, p = 0.017). Furthermore, ADCmean correlated in a statistically significant manner with total nucleic area (r = -0.500, p = 0.021).

Conclusion

Low ADCmin, ADCmean and ADCmax values reflect a high proliferative activity of primary cental nervous system lymphoma. Low ADCmean values—in concordance with several previously published studies—indicate an increased cellularity within the tumor.