A Hyperactive RelA/p65-Hexokinase 2 Signaling Axis Drives Primary Central Nervous System Lymphoma

Translational Research Platform for Malignant Central Nervous System Tumors

Some central nervous system (CNS) malignancies are highly aggressive and urgently need innovative treatment strategies to improve prognosis. A significant concern for therapeutic development is the time-consuming nature of developing treatments for CNS tumors. Therefore, a rapid and efficient translational approach is needed to address this problem. Translational and reverse translational research aims to bridge the gap between laboratory data and clinical applications and has been developed in the field of neuro-oncology. This study presents our translational platform systems for malignant CNS tumors, which combine an intraoperative integrated diagnostic system and comprehensive in vitro and in vivo assay systems. These laboratory systems may contribute to a better understanding of tumor biology and the development of novel therapeutic strategies for the poor prognosis of CNS tumors.

Targeting the tumor microenvironment in primary central nervous system lymphoma: Implications for prognosis

Primary central nervous system lymphoma (PCNSL) is a rare extranodal non-Hodgkin lymphoma, and there is limited research on its tumor microenvironment (TME). Nevertheless, more and more studies have evidence that TME has essential effects on tumor cell proliferation, immune escape, and drug resistance. Thus, it is critical to elucidate the role of TME in PCNSL. The understanding of the PCNSL TME is gradually unfolding, including factors that distinguish it from systemic diffuse large B-cell lymphoma (DLBCL). The TME in PCNSL exhibits both transcriptional and spatial intratumor heterogeneity. Cellular interactions between tumor cells and stroma cells reveal immune evasion signaling. The comparative analysis between PCNSL and DLBCL suggests that PCNSL is more likely to be an immunologically deficient tumor. In PCNSL, T cell exhaustion and downregulation of macrophage immune function are accompanied by suppressive microenvironmental factors such as M2 polarized macrophages, endothelin B receptor, HLA depletion, PD-L1, and TIM-3. MMP-9, Integrin-β1, and ICAM-1/LFA-1 play crucial roles in transendothelial migration towards the CNS, while CXCL13/CXCR5, CD44, MAG, and IL-8 are essential for brain parenchymal invasion. Further, macrophages, YKL-40, CD31, CD105, PD-1/PD-L1 axis, osteopontin, galectin-3, aggregative perivascular tumor cells, and HLA deletion may contribute to poor outcomes in patients with PCNSL. This article reviews the effect of various components of TME on the progression and prognosis of PCNSL patients to identify novel therapeutic targets.

Zanubrutinib delays selinexor resistance evolution in biopsy sample-derived primary central nervous system lymphoma models

Primary central nervous system lymphoma (PCNSL) is a rare and aggressive lymphoma of the brain with poor prognosis. The scarcity of cell lines established using PCNSL makes it difficult to conduct preclinical studies on new drugs. We aimed to explore the effect of selinexor combined with zanubrutinib in PCNSL using established PCNSL cells and an orthotopic PCNSL model. Primary PCNSL cells were successfully cultured. Selinexor inhibited proliferation, induced G1 phase arrest, and promoted apoptosis, however, induced drug resistance in PCNSL. Selinexor combined with zanubrutinib had a synergistic effect on PCNSL and prevented the onset of selinexor resistance in PCNSL by inhibiting AKT signaling. Moreover, selinexor combined with zanubrutinib notably slowed tumor growth and prolonged survival compared to that of the control. Overall, the addition of zanubrutinib to selinexor monotreatment had a synergistic effect in vitro and prolonged survival in vivo.

Recent advances in liquid biopsy of central nervous system lymphomas: case presentations and review of the literature

Surgical biopsy is the gold standard for diagnosing central nervous system (CNS) lymphomas. However, reliable liquid biopsy methods for diagnosing CNS lymphomas have quickly developed and have been implicated in clinical decision-making. In the current report, we introduce two patients for whom liquid biopsy was essential for diagnosing CNS lymphomas and discuss the rapidly growing applications of this technology.

Intraoperative Integrated Diagnostic System for Malignant Central Nervous System Tumors

PURPOSE

The 2021 World Health Organization (WHO) classification of central nervous system (CNS) tumors uses an integrated approach involving histopathology and molecular profiling. Because majority of adult malignant brain tumors are gliomas and primary CNS lymphomas (PCNSL), rapid differentiation of these diseases is required for therapeutic decisions. In addition, diffuse gliomas require molecular information on single-nucleotide variants (SNV), such as IDH1/2. Here, we report an intraoperative integrated diagnostic (i-ID) system to classify CNS malignant tumors, which updates legacy frozen-section (FS) diagnosis through incorporation of a qPCR-based genotyping assay.

EXPERIMENTAL DESIGN

FS evaluation, including GFAP and CD20 rapid IHC, was performed on adult malignant CNS tumors. PCNSL was diagnosed through positive CD20 and negative GFAP immunostaining. For suspected glioma, genotyping for IDH1/2, TERT SNV, and CDKN2A copy-number alteration was routinely performed, whereas H3F3A and BRAF SNV were assessed for selected cases. i-ID was determined on the basis of the 2021 WHO classification and compared with the permanent integrated diagnosis (p-ID) to assess its reliability.

RESULTS

After retrospectively analyzing 153 cases, 101 cases were prospectively examined using the i-ID system. Assessment of IDH1/2, TERT, H3F3AK27M, BRAFV600E, and CDKN2A alterations with i-ID and permanent genomic analysis was concordant in 100%, 100%, 100%, 100%, and 96.4%, respectively. Combination with FS and intraoperative genotyping assay improved diagnostic accuracy in gliomas. Overall, i-ID matched with p-ID in 80/82 (97.6%) patients with glioma and 18/19 (94.7%) with PCNSL.

CONCLUSIONS

The i-ID system provides reliable integrated diagnosis of adult malignant CNS tumors.

Metabolic Enzymes in Viral Infection and Host Innate Immunity

Metabolic enzymes are central players for cell metabolism and cell proliferation. These enzymes perform distinct functions in various cellular processes, such as cell metabolism and immune defense. Because viral infections inevitably trigger host immune activation, viruses have evolved diverse strategies to blunt or exploit the host immune response to enable viral replication. Meanwhile, viruses hijack key cellular metabolic enzymes to reprogram metabolism, which generates the necessary biomolecules for viral replication. An emerging theme arising from the metabolic studies of viral infection is that metabolic enzymes are key players of immune response and, conversely, immune components regulate cellular metabolism, revealing unexpected communication between these two fundamental processes that are otherwise disjointed. This review aims to summarize our present comprehension of the involvement of metabolic enzymes in viral infections and host immunity and to provide insights for potential antiviral therapy targeting metabolic enzymes.

Genetic alterations that deregulate RB and PDGFRA signaling pathways drive tumor progression in IDH2-mutant astrocytoma

In IDH-mutant astrocytoma, IDH2 mutation is quite rare and biological mechanisms underlying tumor progression in IDH2-mutant astrocytoma remain elusive. Here, we report a unique case of IDH2 mutant astrocytoma, CNS WHO grade 3 that developed tumor progression. We performed a comprehensive genomic and epigenomic analysis for primary and recurrent tumors and found that both tumors harbored recurrent IDH2R172K and TP53R248W mutation with CDKN2A/B hemizygous deletion. We also found amplifications of CDK4 and MDM2 with PDGFRA gain in the recurrent tumor and upregulated protein expressions of these genes. We further developed, for the first time, a xenograft mouse model of IDH2R172K and TP53R248W mutant astrocytoma from the recurrent tumor, but not from the primary tumor. Consistent with parent recurrent tumor cells, amplifications of CDK4 and MDM2 and PDGFRA gain were found, while CDKN2A/B was identified as homozygous deletion in the xenografts, qualifying for integrated diagnosis of astrocytoma, IDH2-mutant, CNS WHO grade 4. Cell viability assay found that CDK4/6 inhibitor and PDGFR inhibitor potently decreased cell viability in recurrent tumor cells, as compared to primary tumor cells. These findings suggest that gene alterations that activate retinoblastoma (RB) signaling pathways and PDGFR may drive tumor progression and xenograft formation in IDH2-mutant astrocytoma, which is equivalent to progressive IDH1-mutant astrocytoma. Also, our findings suggest that these genomic alterations may represent therapeutic targets in IDH2-mutant astrocytoma.

Understanding the molecular pathogenesis of primary central nervous system lymphoma by experimental animal models

Primary central nervous system lymphoma (PCNSL) is a rare and invasive diffuse large B cell lymphoma confined in central nervous system (CNS). The effort to press forward the translational progress has been frustrated by the insufficient understanding of immunophenotype of CNS and tumor genetic alterations of PCNSL, and the lack of validated diagnostic biomarkers. Researchers now have a variety of PCNSL animal models at their disposal that resemble the morphology and immunophenotype of PCNSL, however, a careful and detailed re-examination of these animal models is needed to clarify the differences in genetic alterations, migration capability, and immune status. In this review, we present the knowledge about the phenotypic and genotypic features of PCNSL tumor cells, and compile the preclinical animal models of PCNSL with regard to various injection sites, cell origins, recipient animals, and immune status, and elaborate on the tropism and migration of tumor cells and novel therapeutic strategies for PCNSL. We envisage that the selection of suitable animal models will serve as a well-defined preclinical system to understand the molecular pathogenesis of PCNSL, thereby galvanizing the development of novel and potent therapeutic approaches.

Extranodal lymphoma: pathogenesis, diagnosis and treatment

Approximately 30% of lymphomas occur outside the lymph nodes, spleen, or bone marrow, and the incidence of extranodal lymphoma has been rising in the past decade. While traditional chemotherapy and radiation therapy can improve survival outcomes for certain patients, the prognosis for extranodal lymphoma patients remains unsatisfactory. Extranodal lymphomas in different anatomical sites often have distinct cellular origins, pathogenic mechanisms, and clinical manifestations, significantly influencing their diagnosis and treatment. Therefore, it is necessary to provide a comprehensive summary of the pathogenesis, diagnosis, and treatment progress of extranodal lymphoma overall and specifically for different anatomical sites. This review summarizes the current progress in the common key signaling pathways in the development of extranodal lymphomas and intervention therapy. Furthermore, it provides insights into the pathogenesis, diagnosis, and treatment strategies of common extranodal lymphomas, including gastric mucosa-associated lymphoid tissue (MALT) lymphoma, mycosis fungoides (MF), natural killer/T-cell lymphoma (nasal type, NKTCL-NT), and primary central nervous system lymphoma (PCNSL). Additionally, as PCNSL is one of the extranodal lymphomas with the worst prognosis, this review specifically summarizes prognostic indicators and discusses the challenges and opportunities related to its clinical applications. The aim of this review is to assist clinical physicians and researchers in understanding the current status of extranodal lymphomas, enabling them to make informed clinical decisions that contribute to improving patient prognosis.

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.

Aerobic glycolysis enhances HBx-initiated hepatocellular carcinogenesis via NF-κBp65/HK2 signalling

BACKGROUND

Aerobic glycolysis has been recognized as one of the growth-promoting metabolic alterations of cancer cells. Emerging evidence indicates that nuclear factor κB (NF-κB) plays significant roles in metabolic adaptation in normal cells and cancer cells. However, whether and how NF-κB regulates metabolic reprogramming in hepatocellular carcinoma (HCC), specifically hepatitis B virus X protein (HBx)-initiated HCC, has not been determined.

METHODS

A dataset of the HCC cohort from the TCGA database was used to analyse the expression of NF-κB family members. Expression of NF-κBp65 and phosphorylation of NF-κBp65 (p-p65) were detected in liver tissues from HBV-related HCC patients and normal controls. A newly established HBx^+/+/NF-κBp65^f/f and HBx^+/+/NF-κBp65^Δhepa spontaneous HCC mouse model was used to investigate the effects of NF-κBp65 on HBx-initiated hepatocarcinogenesis. Whether and how NF-κBp65 is involved in aerobic glycolysis induced by HBx in hepatocellular carcinogenesis were analysed in vitro and in vivo.

RESULTS

NF-κBp65 was upregulated in HBV-related HCC, and HBx induced NF-κBp65 upregulation and phosphorylation in vivo and in vitro. Hepatocyte-specific NF-κBp65 deficiency remarkably decreased HBx-initiated spontaneous HCC incidence in HBx-TG mice. Mechanistically, HBx induced aerobic glycolysis by activating NF-κBp65/hexokinase 2 (HK2) signalling in spontaneous hepatocarcinogenesis, and overproduced lactate significantly promoted HCC cell pernicious proliferation via the PI3K (phosphatidylinositide 3-kinase)/Akt pathway in hepatocarcinogenesis.

CONCLUSION

The data elucidate that NF-κBp65 plays a pivotal role in HBx-initiated spontaneous HCC, which depends on hyperactive NF-κBp65/HK2-mediated aerobic glycolysis to activate PI3K/Akt signalling. Thus, phosphorylation of NF-κBp65 will be a potential therapeutic target for HBV-related HCC.

HSP90 inhibition overcomes resistance to molecular targeted therapy in BRAFV600E mutant high-grade glioma

PURPOSE

Molecular targeted therapy using BRAF and/or MEK inhibitors has been applied to BRAFV600E mutant high-grade gliomas (HGGs); however, the therapeutic effect is limited by the emergence of drug resistance.

EXPERIMENTAL DESIGN

We established multiple paired BRAFV600E mutant HGG patient-derived xenograft (PDX) models based on tissues collected prior to and at relapse after molecular targeted therapy. Using these models, we dissected treatment resistant mechanisms for molecular targeted therapy and explored therapeutic targets to overcome resistance in BRAFV600E HGG models in vitro and in vivo.

RESULTS

We found that, despite causing no major genetic and epigenetic changes, BRAF and/or MEK inhibitor treatment deregulated multiple negative feedback mechanisms, which led to the re-activation of the MAPK pathway through c-Raf and AKT signaling. This altered oncogenic signaling primarily mediated resistance to molecular targeted therapy in BRAFV600E mutant HGG. To overcome this resistance mechanism, we performed a high-throughput drug screening to identify therapeutic agents that potently induce additive cytotoxicity with BRAF and MEK inhibitors. We discovered that HSP90 inhibition combined with BRAF/MEK inhibition coordinately deactivated the MAPK and AKT/mTOR pathways, and subsequently induced apoptosis via dephosphorylation of GSK3β (Ser9) and inhibition of Bcl-2 family proteins. This mediated potent cytotoxicity in vitro and in vivo in refractory models with acquired resistance to molecular-targeted therapy.

CONCLUSIONS

The combination of an HSP90 inhibitor with BRAF or MEK inhibitors can overcome the limitations of the current therapeutic strategies for BRAFV600E mutant HGG.

The PI3K/AKT/mTOR signaling pathway is aberrantly activated in primary central nervous system lymphoma and correlated with a poor prognosis

Background

Primary central nervous system lymphoma (PCNSL) is a specific subtype of non-Hodgkin lymphoma that is highly invasive and confined to the central nervous system (CNS). The vast majority of PCNSLs are diffuse large B-cell lymphomas (DLBCLs). PCNSL is a highly heterogeneous disease, and its pathogenesis has not yet been fully elucidated. Further studies are needed to guide individualized therapy and improve the prognosis.

Methods

In this study, we detected 1) the expression of p-AKT, p-mTOR, p-S6 and p-4E-BP1 by immunohistochemistry (IHC) and Western blotting, 2) the mRNA expression by real-time qPCR and 3) the deletion of PTEN gene by immunofluorescence in situ hybridization (FISH) in order to investigate the activation status of the PI3K/AKT/mTOR signaling pathway in PCNSL. Samples of reactive hyperplasia lymphnods were used as the control group. The correlations between the clinical characteristics and prognosis of PCNSL patients and the expression of p-AKT, p-mTOR, p-S6 and p-4E-BP1 and the deletion of PTEN were assessed.

Results

The IHC results showed that the positive expression rates of p-AKT, p-mTOR, p-S6 and p-4E-BP1 in PCNSL were significantly higher in the PCNSL group than in the control group (P < 0.05). The relative mRNA expression level of MTOR in PCNSL samples was significantly increased (P = 0.013). Correlation analysis revealed that the expression of p-mTOR was correlated with that of p-AKT, p-S6, p-4E-BP1. PTEN deletion was found in 18.9% of PCNSL samples and was correlated with the expression of p-AKT (P = 0.031). Correlation analysis revealed that the PCNSL relapse rate in the p-mTOR-positive group was 64.5%, significantly higher than that in the negative group (P = 0.001). Kaplan-Meier survival analysis showed inferior progression-free survival (PFS) in the p-mTOR- and p-S6-positive groups (P = 0.002 and 0.009, respectively), and PTEN deletion tended to be related to shorter overall survival (OS) (P = 0.072). Cox regression analysis revealed p-mTOR expression as an independent prognostic factor for a shorter PFS (hazard ratio (HR) =7.849, P = 0.046).

Conclusions

Our results suggest that the PI3K/AKT/mTOR signaling pathway is aberrantly activated in PCNSL and associated with a poor prognosis, which might indicate new therapeutic targets and prognostic factors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09275-z.

Epstein-Barr Virus and Neurological Diseases

Epstein-Barr virus (EBV), also known as human herpesvirus 4, is a double-stranded DNA virus that is ubiquitous in 90–95% of the population as a gamma herpesvirus. It exists in two main states, latent infection and lytic replication, each encoding viral proteins with different functions. Human B-lymphocytes and epithelial cells are EBV-susceptible host cells. EBV latently infects B cells and nasopharyngeal epithelial cells throughout life in most immunologically active individuals. EBV-infected cells, free viruses, their gene products, and abnormally elevated EBV titers are observed in the cerebrospinal fluid. Studies have shown that EBV can infect neurons directly or indirectly via infected B-lymphocytes, induce neuroinflammation and demyelination, promote the proliferation, degeneration, and necrosis of glial cells, promote proliferative disorders of B- and T-lymphocytes, and contribute to the occurrence and development of nervous system diseases, such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, acute cerebellar ataxia, meningitis, acute disseminated encephalomyelitis, and brain tumors. However, the specific underlying molecular mechanisms are unclear. In this paper, we review the mechanisms underlying the role of EBV in the development of central nervous system diseases, which could bebeneficial in providing new research ideas and potential clinical therapeutic targets for neurological diseases.

Prognostic value of [18F]FDG PET/CT in patients with CNS lymphoma receiving ibrutinib-based therapies

PURPOSE

Current clinical and imaging tools remain suboptimal for predicting treatment response and prognosis in CNS lymphomas. We investigated the prognostic value of baseline [18F]FDG PET in patients with CNS lymphoma receiving ibrutinib-based treatments.

METHODS

Fifty-three patients enrolled in a prospective clinical trial and underwent brain PET before receiving single-agent ibrutinib or ibrutinib in combination with methotrexate with or without rituximab. [18F]FDG uptake in these lesions was quantified by drawing PET volumes of interest around up to five [18F]FDG-avid lesions per patient (with uptake greater than surrounding brain). We measured standardized uptake values (SUVmax), metabolic tumor volumes, total lesion glycolysis (TLG), and the sum thereof in these lesions. We analyzed the relationship between PET parameters and mutation status, overall response rates, and progression-free survival (PFS).

RESULTS

Thirty-eight patients underwent single-agent therapy and 15 received combination therapy. On PET, 15/53 patients had no measurable disease. In the other 38 patients, a total of 71 lesions were identified on PET. High-intensity [18F]FDG uptake and a larger volume of [18F]FDG-avid disease were inversely related to treatment outcome (p ≤ 0.005). In univariable analysis, PFS was linearly correlated with all PET parameters, with stronger association when sum-values were used. A multivariable model showed that risk of progression increased by 9% for every 5-unit increase in sumSUVmax (hazard ratio = 1.09 [95% CI: 1.04 to 1.14]).

CONCLUSION

Higher lesional metabolic parameters are inversely related to outcome in patients undergoing ibrutinib-based therapies, and sumSUVmax emerged as a strong independent prognostic factor.

TRIAL REGISTRATION

NCT02315326; https://clinicaltrials.gov/ct2/show/NCT02315326?term=NCT02315326&draw=2&rank=1.

Recent Progress on Primary Central Nervous System Lymphoma-From Bench to Bedside

Primary central nervous system lymphoma (PCNSL) is a rare subtype of extra-nodal lymphoma. The high relapse rate of PCNSL remains a major challenge to the hematologists, even though patients exhibit high sensitivity to the methotrexate-based chemotherapeutic regimens. Recently, the advent of Bruton's tyrosine kinase inhibitor (BTKi) and CAR T treatment has made more treatment options available to a proportion of patients. However, whether BTKi monotherapy should be given alone or in combination with conventional chemotherapy is still a clinical question. The status of CAR T therapy for PCNSLs also needs to be elucidated. In this review, we summarized the latest progress on the epidemiology, pathology, clinical manifestation, diagnosis, and treatment options for PCNSLs.

Nanomedicine Applications in Treatment of Primary Central Nervous System Lymphoma: Current State of the Art

Primary central nervous system lymphoma (PCNSL) is a rare but highly aggressive subtype of extra nodal non-Hodgkin lymphoma (NHL), which is confined in the central nervous system (CNS). Despite recent advancements in treatment options, the overall prognosis of PCNSL remains poor. Among many unfavorable factors affecting efficacy, inadequate drug delivery into the CNS is still the thorniest challenge. Blood-brain barrier (BBB) constitutes a significant impediment, restricting entry of most therapeutics to the brain. Nanotechnology has offered great promise for brain diseases, as various nano-based drug delivery systems (NDDSs) have been developed for delivery of theranostic agents in to the CNS. These drug delivery systems possess significant advantages, including good feasibility, reliable safety profile, excellent BBB penetration and potent antitumor effects. As for treatment of PCNSL, numerous well-developed BBB-crossing nano-based strategies can be applied with proper modifications and improvements. Some exquisitely designed NDDSs specific for PCNSL have shown great potential. In this review, we provide a summary on current status of diagnosis and treatment of PCNSL, followed by an overview of BBB-crossing strategies applied in management of PCNSL, both novel and wellestablished. Finally, challenges and future perspectives in this field are also discussed.

Primary central nervous system lymphoma: clinicopathological and genomic insights for therapeutic development

Primary central nervous system lymphoma (PCNSL) is a highly aggressive, extra-nodal non-Hodgkin lymphoma that is confined to the central nervous system (CNS) and the eyes. Most PCNSLs arise in immunocompetent older patients and less frequently in immunocompromised patients with Epstein-Barr virus infection. Although a patient's initial response to chemotherapy and radiation therapy is favorable, the clinical outcome of PCNSL remains poor compared to that of systemic lymphoma. Radiation-induced neurotoxicity is also a critical problem for patients with PCNSL. Therefore, a novel therapeutic strategy is required to overcome these challenges. Recent studies have largely uncovered the genomic landscape and associated histopathological features of PCNSL. Based on this background, novel therapeutic agents, such as Bruton's tyrosine kinase inhibitors and immune checkpoint inhibitors, have been introduced for patients with PCNSL. Here, we provide an overview of the updated histopathological and genomic characterization of PCNSL and summarize the current therapeutic strategies. We also review current preclinical PCNSL models for translational research.

Positron emission tomography and magnetic resonance imaging in primary central nervous system lymphoma-a narrative review

This review addresses the challenges of primary central nervous system (CNS) lymphoma diagnosis, assessment of treatment response, and detection of recurrence. Primary CNS lymphoma is a rare form of extra-nodal non-Hodgkin lymphoma that can involve brain, spinal cord, leptomeninges, and eyes. Primary CNS lymphoma lesions are most commonly confined to the white matter or deep cerebral structures such as basal ganglia and deep periventricular regions. Contrast-enhanced magnetic resonance imaging (MRI) is the standard diagnostic modality employed by neuro-oncologists. MRI often shows common morphological features such as a single or multiple uniformly well-enhancing lesions without necrosis but with moderate surrounding edema. Other brain tumors or inflammatory processes can show similar radiological patterns, making differential diagnosis difficult. [18F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) has selected utility in cerebral lymphoma, especially in diagnosis. Primary CNS lymphoma can sometimes present with atypical findings on MRI and FDG PET, such as disseminated disease, non-enhancing or ring-like enhancing lesions. The complementary strengths of PET and MRI have led to the development of combined PET-MR systems, which in some cases may improve lesion characterization and detection. By highlighting active developments in this field, including advanced MRI sequences, novel radiotracers, and potential imaging biomarkers, we aim to spur interest in sophisticated imaging approaches.

Hexokinase 2 in Cancer: A Prima Donna Playing Multiple Characters

Hexokinases are a family of ubiquitous exose-phosphorylating enzymes that prime glucose for intracellular utilization. Hexokinase 2 (HK2) is the most active isozyme of the family, mainly expressed in insulin-sensitive tissues. HK2 induction in most neoplastic cells contributes to their metabolic rewiring towards aerobic glycolysis, and its genetic ablation inhibits malignant growth in mouse models. HK2 can dock to mitochondria, where it performs additional functions in autophagy regulation and cell death inhibition that are independent of its enzymatic activity. The recent definition of HK2 localization to contact points between mitochondria and endoplasmic reticulum called Mitochondria Associated Membranes (MAMs) has unveiled a novel HK2 role in regulating intracellular Ca²⁺ fluxes. Here, we propose that HK2 localization in MAMs of tumor cells is key in sustaining neoplastic progression, as it acts as an intersection node between metabolic and survival pathways. Disrupting these functions by targeting HK2 subcellular localization can constitute a promising anti-tumor strategy.