PD-L1 and IDO1 are potential targets for treatment in patients with primary diffuse large B-cell lymphoma of the CNS

The prognostic value of CD8+ CTLs, CD163+ TAMs, and PDL1 expression in the tumor microenvironment of primary central nervous system lymphoma

To explore immune cell infiltration and PDL1 expression in the tumor microenvironment (TME) of primary central nervous system lymphoma (PCNSL), we performed immunohistochemical staining on paraffin-embedded tumor tissues from 34 patients diagnosed with PCNSL. CD8 and CD163 positive cells were manually counted, and PDL1 expression was quantified by the H-score scoring method in the tumor center and around the tumor. The Kaplan-Meier method was used to analyze the prognostic value of the TME. We found obvious infiltration of CD8+ CTLs and CD163+ TAMs in the TME of PCNSL patients. And PDL1 was expressed in the tumor center as well as around the tumor. Survival analysis showed that high CD8+ CTLs levels and high intratumoral PDL1 expression were significantly correlated with longer OS. High CD8+ CTLs and CD163+ TAMs levels were associated with longer PFS.

The role of comorbidity indices and histochemical markers in surgically resected and non-resected primary central nervous system lymphoma

The role of surgical resection in primary central nervous system lymphoma (PCNSL) was not recognized until recently. However, prognostic factors for surgically treated PCNSL remain unclear. In the present study, we aimed to identify and compare the prognostic value of comorbidity indices and immunohistochemical markers in patients with surgically and non-surgically treated PCNSL. This retrospective single-center study analyzed patients who underwent either surgical resection or stereotactic biopsy for newly diagnosed PCNSL between January 2012 and December 2021. Clinical demographics, comorbidity indices, and immunohistochemical markers were analyzed. We included 23 and 18 patients who underwent stereotactic biopsy and surgical resection, respectively. The median overall survival (OS) was 11.05 months. Using multivariate Cox regression, we identified pretreatment prognostic nutritional index (PNI) (p = 0.009), positive BCL2 staining (p = 0.026), and infratentorial involvement (p = 0.004) as independent prognostic factors of OS. Predictors of progression-free survival (PFS) included PNI (p = 0.040), infratentorial involvement (p = 0.021), and surgical resection for PCNSL (p = 0.048). Subgroup analyses revealed that positive BCL2 (p = 0.048) and PD-L1 (p = 0.037) staining were associated with worse OS in the biopsy group. PNI and infratentorial involvement could significantly impact both OS and PFS in patients with PCNSL. Surgical resection could predict favorable PFS but not OS. Moreover, BCL2 and PD-L1 expression can be employed as prognostic markers in these patients.

Spatial single cell analysis of tumor microenvironment remodeling pattern in primary central nervous system lymphoma

To determine the overall tumor microenvironment (TME), characteristics, and transition mechanisms in primary central nervous system lymphoma (PCNSL), we performed spatial transcriptomics and matched the corresponding single-cell sequencing data of PCNSL patients. We found that tumor cells may achieve a "TME remodeling pattern" through an "immune pressure-sensing model", in which they could choose to reshape the TME into a barrier environment or a cold environment according to the immune pressure. A key FKBP5+ tumor subgroup was found to be responsible for pushing tumors into the barrier environment, which provides a possible way to evaluate the stage of PCNSL. The specific mechanism of the TME remodeling pattern and the key molecules of the immune pressure-sensing model were identified through the spatial communication analysis. Finally, we discovered the spatial and temporal distributions and variation characteristics of immune checkpoint molecules and CAR-T target molecules in immunotherapy. These data clarified the TME remodeling pattern of PCNSL, provided a reference for its immunotherapy, and provided suggestions for the TME remodeling mechanism of other cancers.

Interactions of IDO and the Kynurenine Pathway with Cell Transduction Systems and Metabolism at the Inflammation-Cancer Interface

The mechanisms underlying a relationship between inflammation and cancer are unclear, but much emphasis has been placed on the role of tryptophan metabolism to kynurenine and downstream metabolites, as these make a substantial contribution to the regulation of immune tolerance and susceptibility to cancer. The proposed link is supported by the induction of tryptophan metabolism by indoleamine-2,3-dioxygenase (IDO) or tryptophan-2,3-dioxygenase (TDO), in response to injury, infection or stress. This review will summarize the kynurenine pathway and will then focus on the bi-directional interactions with other transduction pathways and cancer-related factors. The kynurenine pathway can interact with and modify activity in many other transduction systems, potentially generating an extended web of effects other than the direct effects of kynurenine and its metabolites. Conversely, the pharmacological targeting of those other systems could greatly enhance the efficacy of changes in the kynurenine pathway. Indeed, manipulating those interacting pathways could affect inflammatory status and tumor development indirectly via the kynurenine pathway, while pharmacological modulation of the kynurenine pathway could indirectly influence anti-cancer protection. While current efforts are progressing to account for the failure of selective IDO1 inhibitors to inhibit tumor growth and to devise means of circumventing the issue, it is clear that there are wider factors involving the relationship between kynurenines and cancer that merit detailed consideration as alternative drug targets.

Expression of IDO1 and PD-L2 in Patients with Benign Lymphadenopathies and Association with Autoimmune Diseases

The expression patterns of IDO1 and PD-L2 have not been thoroughly investigated in benign lymphadenopathies. The aim with this study was to elucidate how IDO1 and PD-L2 are expressed in benign lymphadenopathies in patients with autoimmune diseases (AD) compared to patients without AD. Formalin-fixed paraffin-embedded lymph nodes from 22 patients with AD and 57 patients without AD were immunohistochemically stained to detect IDO1 and PD-L2. The material was previously stained with EBER in situ hybridization to detect cells harboring the Epstein-Barr virus (EBV). IDO1 and PD-L2 were generally expressed by leukocytes to low degrees, while follicular IDO1+ cells were very rare. IDO1+ cells in single germinal centers were detected in five patients, and there was a high co-occurrence of follicular EBV+ cells in these cases (three of five patients). There were also significant correlations between interfollicular EBV+ cells and interfollicular IDO1+ cells (Spearman rho = 0.32, p = 0.004) and follicular IDO1+ cells (Spearman rho = 0.34, p = 0.004). High or low amounts of IDO1+ or PD-L2+ cells were not statistically significantly associated with patients with AD. However, the lymphadenopathy with the highest amount of interfollicular IDO1+ cells, which was also the only lymphadenopathy in which endothelial cells expressed IDO1, was in a patient with sarcoidosis. This study further supports that the EBV induces the expression of IDO1 and our findings should be recognized by future studies on IDO1 and PD-L2 in inflammatory and malignant conditions.

Molecular characteristics of immunocytes infiltration in primary central nervous system lymphoma

Background: Primary central nervous system lymphoma (PCNSL) is a rare B-cell lymphoma of central nervous system, which is often found in immunocompromised patients. The common clinical treatment of PCNSL is methotrexate (MTX) and whole brain radiation therapy. With the development of tumour immunology research, the tumour microenvironment of PCNSL is characterised by abnormal expression of different immune signature molecules and patients with PCNSL may benefit from tumour immunotherapy.

Methods: In our research, RNA-seq data from 82 PCNSL patients were collated by mining the microarray data from the GEO database. All samples were classified into three types related to tumour immune response by the Cibersort algorithm and consistent clustering. Differential analysis of genes was used to uncover 2 sets of differential genes associated with tumour immunity. The ICI scores of each sample were obtained by PCA algorithm, and the relationship between ICI scores and immune checkpoint expression, immunotherapy and drug sensitivity was investigated. Genes associated with ICI scores and their functional characteristics were investigated by WGCNA analysis and PPI analysis, based on the ICI scores of each sample.

Results: The tumour microenvironment in PCNSL has a greater relationship with the tumour immune response. ICI scores obtained from 375 differential genes were associated with multiple immune responses in PCNSL. PCNSL patients with higher ICI scores had a better tumour microenvironment and were sensitive to immunotherapy and some small molecule drug. This study also identified 64 genes associated with ICI scores, which may serve as important therapeutic and prognostic targets for PCNSL.

Conclusion: The presence of multiple immunosuppressive responses in the tumour microenvironment of PCNSL which suggested that improving the immune function of PCNSL patients through immunotherapy and targeted therapies can be an effective treatment for PCNSL. And the ICI score and associated genes may also provide a better predictor of the clinical use of immunotherapy.

Biological and Clinical Implications of Gene-Expression Profiling in Diffuse Large B-Cell Lymphoma: A Proposal for a Targeted BLYM-777 Consortium Panel as Part of a Multilayered Analytical Approach

Gene-expression profiling (GEP) is used to study the molecular biology of lymphomas. Here, advancing insights from GEP studies in diffuse large B-cell lymphoma (DLBCL) lymphomagenesis are discussed. GEP studies elucidated subtypes based on cell-of-origin principles and profoundly changed the biological understanding of DLBCL with clinical relevance. Studies integrating GEP and next-generation DNA sequencing defined different molecular subtypes of DLBCL entities originating at specific anatomical localizations. With the emergence of high-throughput technologies, the tumor microenvironment (TME) has been recognized as a critical component in DLBCL pathogenesis. TME studies have characterized so-called "lymphoma microenvironments" and "ecotypes". Despite gained insights, unexplained chemo-refractoriness in DLBCL remains. To further elucidate the complex biology of DLBCL, we propose a novel targeted GEP consortium panel, called BLYM-777. This knowledge-based biology-driven panel includes probes for 777 genes, covering many aspects regarding B-cell lymphomagenesis (f.e., MYC signature, TME, immune surveillance and resistance to CAR T-cell therapy). Regarding lymphomagenesis, upcoming DLBCL studies need to incorporate genomic and transcriptomic approaches with proteomic methods and correlate these multi-omics data with patient characteristics of well-defined and homogeneous cohorts. This multilayered methodology potentially enhances diagnostic classification of DLBCL subtypes, prognostication, and the development of novel targeted therapeutic strategies.

Specific TCR V-J gene segment recombinations leading to the identification pan-V-J CDR3s associated with survival distinctions: diffuse large B-cell lymphoma

In the diffuse large B-cell lymphoma (DLBCL) setting, we examined lymph node biopsy, T-cell receptor features, and the DLBLC patient human leukocyte antigen (HLA) alleles, to provide a basis for assessing survival distinctions represented by the National Cancer Institute Center for Cancer Research (NCICCR) dataset. While previous analyses of other cancer datasets have indicated that specific T-cell receptor (TCR) V or J gene segments, independently, can be associated with a survival distinction, we have here identified V-J recombinations, representing specific V and J gene segments associated with survival distinctions. As specific V-J recombinations represent relatively conserved complementarity determining region-3 (CDR3) amino acid sequences, we assessed the entire DLBCL NCICCR dataset for such conserved CDR3 features. Overall, this approach indicated the opportunity of identifying DLBCL patient subpopulations with TCR CDR3 features, and HLA alleles, with significant survival distinctions, possibly identifying cohorts more likely to benefit from a given immunotherapy.

Prognostic implications of the tumor immune microenvironment and immune checkpoint pathway in primary central nervous system diffuse large B-cell lymphoma in the North Indian population

Primary central nervous system-diffuse large B-cell lymphoma (PCNS-DLBCL) is a rare, extranodal malignant lymphoma carrying poor prognosis. The prognostic impact of tumor microenvironment (TME) composition and the PD-1/PD-L1 immune checkpoint pathway are still undetermined in PCNS-DLBCL. We aimed to quantify the tumor-infiltrating lymphocytes (TILs), tumor-associated macrophages (TAMs), and PD-L1 expression in the PCNSL and evaluated their prognostic significance. All patients with histopathologically diagnosed PCNS-DLBCL over a period of 7 years were recruited. Immunohistochemistry for CD3, CD4, CD8, FOXP3, CD68, CD163, PD-1, and PD-L1 was performed on the tissue microarray. Forty-four cases of PCNS-DLBCL, who satisfied the selection criteria, were included with mean age of 55 ± 12.3 years and male-to-female ratio of 0.91:1. The mean overall survival (OS) and disease-free survival (DFS) was 531.6 days and 409.8 days, respectively. Among TILs, an increased number of CD3+ T cells showed better OS and DFS, without achieving statistical significance. CD4 positive T-cells were significantly associated with the longer OS (p = 0.037) and DFS (p = 0.023). TAMs (68CD and CD163 positive) showed an inverse relationship with OS and DFS but did not reach statistical significance (p > 0.05). Increased PD-L1 expression in immune cells, but not in tumor cells, was associated with significantly better DFS (p = 0.037). The TME plays a significant role in the prognosis of PCNS-DLBCL. Increased number of CD4+ T cells and PD-L1-expressing immune cells is associated with better prognosis in PCNS-DLBCL. Further studies with larger sample size are required to evaluate the role of targeted therapy against the TME and immune check point inhibitors in this disease.