High expression of tumor-infiltrating macrophages correlates with poor prognosis in patients with diffuse large B-cell lymphoma

Unraveling the Immune Microenvironment in Diffuse Large B-Cell Lymphoma: Prognostic and Potential Therapeutic Implications

Diffuse large B cell lymphoma (DLBCL) is a multifaceted condition characterized by significant diversity in its molecular and pathological subtypes and clinical manifestation. Despite the progress made in the treatment of DLBCL through the development of novel drugs, an estimated one-third of patients encounter relapse or acquire refractory disease. The tumor microenvironment (TME) of DLBCL, a complex network consisting of cellular and noncellular components that engage in interactions with the tumor, is a parameter that is gaining increasing attention. The TME comprises both the immune and nonimmune microenvironments. The immune microenvironment comprises natural killer (NK) cells, dendritic cells (DCs), tumor-associated macrophages (TAMs), neutrophils, myeloid-derived suppressor cells (MDSCs), and T and B lymphocytes. The nonimmune microenvironment consists of the extracellular matrix (ECM), cancer-associated fibroblasts (CAFs), mesenchymal stromal cells, and other molecules that are secreted. Despite ongoing research, the exact impact of these components and their interaction on the progression of the disease remains elusive. A comprehensive review of significant discoveries concerning the cellular and noncellular constituents, molecular characteristics, and treatment response and prognosis of the TME in DLBCL, as well as the potential targeting of the TME with novel therapeutic approaches, is provided in this article.

Macrophages and angiogenesis in human lymphomas

A link exists between chronic inflammation and cancer and immune cells, angiogenesis, and tumor progression. In hematologic malignancies, tumor-associated macrophages (TAMs) are a significant part of the tumor microenvironment. Macrophages are classified into M1/classically activated and M2/alternatively activated. In tumors, TAMs are mainly constituted by M2 subtype, which promotes angiogenesis, lymphangiogenesis, repair, and remodeling, suppressing adaptive immunity, increasing tumor cell proliferation, drug resistance, histological malignancy, and poor clinical prognosis. The aim of our review article is to define the role of TAMs and their relationship with the angiogenesis in patients with lymphoma reporting both an analysis of main published data and those emerging from our studies. Finally, we have discussed the anti-angiogenic approach in the treatment of lymphomas.

The Oncogenic Lipid Sphingosine-1-Phosphate Impedes the Phagocytosis of Tumor Cells by M1 Macrophages in Diffuse Large B Cell Lymphoma

BACKGROUND

A total of 30-40% of diffuse large B cell lymphoma (DLBCL) patients will either not respond to the standard therapy or their disease will recur. The first-line treatment for DLBCL is rituximab and combination chemotherapy. This treatment involves the chemotherapy-induced recruitment of tumor-associated macrophages that recognize and kill rituximab-opsonized DLBCL cells. However, we lack insights into the factors responsible for the recruitment and functionality of macrophages in DLBCL tumors.

METHODS

We have studied the effects of the immunomodulatory lipid sphingosine-1-phosphate (S1P) on macrophage activity in DLBCL, both in vitro and in animal models.

RESULTS

We show that tumor-derived S1P mediates the chemoattraction of both monocytes and macrophages in vitro and in animal models, an effect that is dependent upon the S1P receptor S1PR1. However, S1P inhibited M1 macrophage-mediated phagocytosis of DLBCL tumor cells opsonized with the CD20 monoclonal antibodies rituximab and ofatumumab, an effect that could be reversed by an S1PR1 inhibitor.

CONCLUSIONS

Our data show that S1P signaling can modulate macrophage recruitment and tumor cell killing by anti-CD20 monoclonal antibodies in DLBCL. The administration of S1PR1 inhibitors could enhance the phagocytosis of tumor cells and improve outcomes for patients.

The Immunology of DLBCL

Diffuse large B-cell lymphoma (DLBCL) is an aggressive malignancy and is the most common type of malignant lymphoid neoplasm. While some DLBCLs exhibit strong cell-autonomous survival and proliferation activity, others depend on interactions with non-malignant cells for their survival and proliferation. Recent next-generation sequencing studies have linked these interactions with the molecular classification of DLBCL. For example, germinal center B-cell-like DLBCL tends to show strong associations with follicular T cells and epigenetic regulation of immune recognition molecules, whereas activated B-cell-like DLBCL shows frequent genetic aberrations affecting the class I major histocompatibility complex. Single-cell technologies have also provided detailed information about cell-cell interactions and the cell composition of the microenvironment of DLBCL. Aging-related immunological deterioration, i.e., immunosenescence, also plays an important role in DLBCL pathogenesis, especially in Epstein-Barr virus-positive DLBCL. Moreover, DLBCL in "immune-privileged sites"-where multiple immune-modulating mechanisms exist-shows unique biological features, including frequent down-regulation of immune recognition molecules and an immune-tolerogenic tumor microenvironment. These advances in understanding the immunology of DLBCL may contribute to the development of novel therapies targeting immune systems.

The prognostic value of tumor-associated macrophages detected by immunostaining in diffuse large B cell lymphoma: A meta-analysis

Background

The prognostic implication of tumor-associated macrophages (TAMs) in the microenvironment of diffuse large B cell lymphoma (DLBCL) remains controversial.

Methods

A systematic and comprehensive search of relevant studies was performed in PubMed, Embase and Web of Science databases. The quality of the included studies was estimated using Newcastle-Ottawa Scale (NOS).

Results

Twenty-three studies containing a total of 2992 DLBCL patients were involved in this study. They were all high-quality studies scoring ≥ 6 points. High density of M2 TAMs in tumor microenvironment significantly associated with both advanced disease stage (OR= 1.937, 95% CI: 1.256-2.988, P = 0.003) and unfavorable overall survival (OS) (HR = 1.750, 95% CI: 1.188-2.579, P = 0.005) but not associated with poor progression free survival (PFS) (HR = 1.672, 95% CI: 0.864-3.237, P = 0.127) and international prognostic index (IPI) (OR= 1.705, 95% CI: 0.843-3.449, P = 0.138) in DLBCL patients. No significant correlation was observed between the density of CD68+ TAMs and disease stage (OR= 1.433, 95% CI: 0.656-3.130, P = 0.366), IPI (OR= 1.391, 95% CI: 0.573-3.379, P = 0.466), OS (HR=0.929, 95% CI: 0.607-1.422, P = 0.734) or PFS (HR= 0.756, 95% CI: 0.415-1.379, P = 0.362) in DLBCL patients.

Conclusion

This meta-analysis demonstrated that high density of M2 TAMs in the tumor microenvironment was a robust predictor of adverse outcome for DLBCL patients.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42022343045.

Tumor-infiltrating lymphocytes and macrophages as a significant prognostic factor in biliary tract cancer

BACKGROUND

The impact of tumor-infiltrating lymphocytes (TILs) and tumor-associated macrophages (TAMs) on the prognosis of biliary tract cancer (BTC) is not completely understood. Therefore, in our study, we investigated the effects of the various immune cells infiltration in tumor microenvironment (TME).

METHODS

A total of 130 patients with BTC who underwent surgical treatment at our institution were enrolled in this study. We retrospectively evaluated TILs and TAMs with immunohistochemical staining.

RESULTS

With CD8-high, CD4-high, FOXP3-high, and CD68-low in TME as one factor, we calculated Immunoscore according to the number of factors. The high Immunoscore group showed significantly superior overall survival (OS) and recurrence-free survival (RFS) than the low Immunoscore group (median OS, 60.8 vs. 26.4 months, p = 0.001; median RFS not reached vs. 17.2 months, p < 0.001). Also, high Immunoscore was an independent good prognostic factor for OS and RFS (hazards ratio 2.05 and 2.41 and p = 0.01 and p = 0.001, respectively).

CONCLUSIONS

High Immunoscore group had significantly superior OS and RFS and was an independent good prognostic factor for OS and RFS.

Lymphoma Microenvironment in DLBCL and PTCL-NOS: the key to uncovering heterogeneity and the potential for stratification

Diffuse large B-cell lymphoma (DLBCL) and peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) are the most common subtypes of mature B cell neoplasm and T/NK cell lymphoma, respectively. They share a commonality in that they are, by definition, highly heterogeneous populations. Recent studies are revealing more about the heterogeneity of these diseases, and at the same time, there is an active debate on how to stratify these heterogeneous diseases and make them useful in clinical practice. The various immune cells and non-cellular components surrounding lymphoma cells, i.e., the lymphoma microenvironment, have been the subject of intense research since the late 2000s, and much knowledge has been accumulated over the past decade. As a result, it has become clear that the lymphoma microenvironment, despite its paucity in tissues, significantly impacts the lymphoma pathogenesis and clinical behavior, such as its prognosis and response to therapy. In this article, we review the role of the lymphoma microenvironment in DLBCL and PTCL-NOS, with particular attention given to its impact on the prognosis and stratification.

Role and Mechanisms of Tumor-Associated Macrophages in Hematological Malignancies

Mounting evidence has revealed that many nontumor cells in the tumor microenvironment, such as fibroblasts, endothelial cells, mesenchymal stem cells, and leukocytes, are strongly involved in tumor progression. In hematological malignancies, tumor-associated macrophages (TAMs) are considered to be an important component that promotes tumor growth and can be polarized into different phenotypes with protumor or antitumor roles. This Review emphasizes research related to the role and mechanisms of TAMs in hematological malignancies. TAMs lead to poor prognosis by influencing tumor progression at the molecular level, including nurturing cancer stem cells and laying the foundation for metastasis. Although detailed molecular mechanisms have not been clarified, TAMs may be a new therapeutic target in hematological disease treatment.

The Effect of the Tumor Microenvironment on Lymphoid Neoplasms Derived from B Cells

Lymphomas are characteristic tumors surrounded by an inflammatory microenvironment. The cells of the microenvironment are essential for the growth and survival of neoplastic cells and are recruited through the effect of cytokines/chemokines. Lymphomas include heterogeneous groups of neoplasms infiltrating various lymphoid structures which may arise from B lymphocytes, T lymphocytes, and natural killer (NK) cells at various stages of their differentiation state. In this review article, we analyze the literature data concerning the involvement of the tumor microenvironment (TME) in the progression of lymphomas and the recent advances in the analysis of microenvironment components in the most common forms: some mature B cell lymphoma neoplasms and classic Hodgkin lymphomas. The complex crosstalk between the TME and tumor cells led to the discovery of many mechanisms usable as molecular-targeted therapy through the control of diverse elements of the TME, varying from inhibitors of angiogenic cytokines and their receptors to the regulation of cells' activities and the novel immune checkpoint inhibitors.

Clinical Impact of Immune Cells and Their Spatial Interactions in Diffuse Large B-Cell Lymphoma Microenvironment

PURPOSE

Tumor-infiltrating immune cells have prognostic significance and are attractive therapeutic targets. Yet, the clinical significance of their spatial organization and phenotype in diffuse large B-cell lymphoma (DLBCL) is unclear.

EXPERIMENTAL DESIGN

We characterized T cells, macrophages, and their spatial interactions by multiplex IHC (mIHC) in 178 patients with DLBCL and correlated the data with patient demographics and survival. We validated the findings on gene expression data from two external DLBCL cohorts comprising 633 patients.

RESULTS

Macrophage and T-cell contents divided the samples into T cell-inflamed (60%) and noninflamed (40%) subgroups. The T cell-inflamed lymphoma microenvironment (LME) was also rich in other immune cells, defining immune hot phenotype, which did not as such correlate with outcome. However, when we divided the patients according to T-cell and macrophage contents, LME characterized by high T-cell/low macrophage content or a corresponding gene signature was associated with superior survival [5-year overall survival (OS): 92.3% vs. 74.4%, P = 0.036; 5-year progression-free survival (PFS): 92.6% vs. 69.8%, P = 0.012]. High proportion of PD-L1- and TIM3-expressing CD163- macrophages in the T cell-inflamed LME defined a group of patients with poor outcome [OS: HR = 3.22, 95% confidence interval (CI), 1.63-6.37, Padj = 0.011; PFS: HR = 2.76, 95% CI, 1.44-5.28, Padj = 0.016]. Furthermore, PD-L1 and PD-1 were enriched on macrophages interacting with T cells.

CONCLUSIONS

Our data demonstrate that the interplay between macrophages and T cells in the DLBCL LME is immune checkpoint dependent and clinically meaningful.

Epigenetic, Metabolic, and Immune Crosstalk in Germinal-Center-Derived B-Cell Lymphomas: Unveiling New Vulnerabilities for Rational Combination Therapies

B-cell non-Hodgkin lymphomas (B-NHLs) are highly heterogenous by genetic, phenotypic, and clinical appearance. Next-generation sequencing technologies and multi-dimensional data analyses have further refined the way these diseases can be more precisely classified by specific genomic, epigenomic, and transcriptomic characteristics. The molecular and genetic heterogeneity of B-NHLs may contribute to the poor outcome of some of these diseases, suggesting that more personalized precision-medicine approaches are needed for improved therapeutic efficacy. The germinal center (GC) B-cell like diffuse large B-cell lymphomas (GCB-DLBCLs) and follicular lymphomas (FLs) share specific epigenetic programs. These diseases often remain difficult to treat and surprisingly do not respond advanced immunotherapies, despite arising in secondary lymphoid organs at sites of antigen recognition. Epigenetic dysregulation is a hallmark of GCB-DLBCLs and FLs, with gain-of-function (GOF) mutations in the histone methyltransferase EZH2, loss-of-function (LOF) mutations in histone acetyl transferases CREBBP and EP300, and the histone methyltransferase KMT2D representing the most prevalent genetic lesions driving these diseases. These mutations have the common effect to disrupt the interactions between lymphoma cells and the immune microenvironment, via decreased antigen presentation and responsiveness to IFN-γ and CD40 signaling pathways. This indicates that immune evasion is a key step in GC B-cell lymphomagenesis. EZH2 inhibitors are now approved for the treatment of FL and selective HDAC3 inhibitors counteracting the effects of CREBBP LOF mutations are under development. These treatments can help restore the immune control of GCB lymphomas, and may represent optimal candidate agents for more effective combination with immunotherapies. Here, we review recent progress in understanding the impact of mutant chromatin modifiers on immune evasion in GCB lymphomas. We provide new insights on how the epigenetic program of these diseases may be regulated at the level of metabolism, discussing the role of metabolic intermediates as cofactors of epigenetic enzymes. In addition, lymphoma metabolic adaptation can negatively influence the immune microenvironment, further contributing to the development of immune cold tumors, poorly infiltrated by effector immune cells. Based on these findings, we discuss relevant candidate epigenetic/metabolic/immune targets for rational combination therapies to investigate as more effective precision-medicine approaches for GCB lymphomas.

Different spatial distribution of inflammatory cells in the tumor microenvironment of ABC and GBC subgroups of diffuse large B cell lymphoma

Diffuse Large B-Cell Lymphoma (DLBCL) presents a high clinical and biological heterogeneity, and the tumor microenvironment chracteristics are important in its  progression. The aim of this study was to evaluate tumor T, B cells, macrophages and mast cells distribution in GBC and ABC DLBCL subgroups through a set of morphometric parameters allowing to provide a quantitative evaluation of the morphological features of the spatial patterns generated by these inflammatory cells.   Histological ABC and GCB samples were immunostained for CD4, CD8, CD68, CD 163, and tryptase in order to determine both percentage and position of positive cells in the tissue characterizing their spatial distribution. The results evidenced that cell patterns generated by CD4-, CD8-, CD68-, CD163- and tryptase-positive cell profiles exhibited a significantly higher uniformity index in ABC than in GCB subgroup. The positive-cell distributions appeared clustered in tissues from GCB, while in tissues from ABC such a feature was lower or absent. The combinations of spatial statistics-derived parameters can lead to better predictions of tumor cell infiltration than any classical morphometric method providing a more accurate description of the functional status of the tumor, useful for patient prognosis.

The Role of Tumor-Associated Macrophages in Hematologic Malignancies

Simple Summary

Tumor-associated macrophages (TAM) represent a leading component of the tumor microenvironment in hematologic malignancies. TAM could display antitumor activity or, conversely, could contribute to tumor growth and survival, depending on their polarization. TAM are polarized towards form M1, with a pro-inflammatory phenotype and an antineoplastic activity, or M2, with an alternately activated phenotype, associated with a poor outcome in patients presenting with leukemia, lymphoma or multiple myeloma. The molecular mechanisms of TAM in different types of hematologic malignancies are different due to the peculiar microenvironment of each disease. TAM could contribute to tumor progression, reduced apoptosis and angiogenesis; a different TAM polarization could explain a reduced treatment response in patients with a similar disease subtype. The aim of our review is to better define the role of TAM in patients with leukemia, lymphoma or multiple myeloma. Finally, we would like to focus on TAM as a possible target for antineoplastic therapy.

Abstract

The tumor microenvironment includes dendritic cells, T-cytotoxic, T-helper, reactive B-lymphoid cells and macrophages; these reactive cells could interplay with malignant cells and promote tumor growth and survival. Among its cellular components, tumor-associated macrophages (TAM) represent a component of the innate immune system and play an important role, especially in hematologic malignancies. Depending on the stimuli that trigger their activation, TAM are polarized towards form M1, contributing to antitumor responses, or M2, associated with tumor progression. Many studies demonstrated a correlation between TAM, disease progression and the patient’s outcome in lymphoproliferative neoplasms, such as Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL), even if with conflicting results. A critical hurdle to overcome is surely represented by the heterogeneity in the choice of the optimal markers and methods used for TAM analysis (gene-expression profile vs. immunohistochemistry, CD163vs. CD68vs. CD163/CD68 double-positive cells). TAM have been recently linked to the development and progression of multiple myeloma and leukemia, with a critical role in the homing of malignant cells, drug resistance, immune suppression and angiogenesis. As such, this review will summarize the role of TAM in different hematologic malignancies, focusing on the complex interplay between TAM and tumor cells, the prognostic value of TAM and the possible TAM-targeted therapeutic strategies.

Prognostic Value of Peripheral Blood Lymphocyte/monocyte Ratio in Lymphoma

Objective: Lymphocyte monocyte ratio (LMR) has been considered as a prognostic factor in patients with lymphoma, which focused on diffuse large B-cell lymphoma (DLBCL) and Hodgkin lymphoma (HL). Recently, many relevant clinical studies have been published with inconsistent results. To gain a more comprehensive view of the prognostic value of LMR, we conducted a meta-analysis on the significance of peripheral LMR in all subtypes of lymphoma.

Methods: PubMed, PMC, Web of Science, Embase, and Cochrane Library were searched for relevant articles to conduct a meta-analysis. Hazard ratio (HR) and its 95% confidence interval (CI) of OS and PFS were extracted and pooled on stata12.1.

Results: In the meta-analysis, forty studies were eligible and a total of 10446 patients were included. Low LMR was associated with an inferior OS (HR=2.45, 95%CI 1.95-3.08) and PFS (HR=2.36, 95%CI 1.94-2.88). In the analysis of lymphoma subtypes, similar results were seen in HL, NHL, and its subtypes including DLBCL, NK/T cell lymphoma, and follicular lymphoma. In addition, low LMR was related with higher LDH (OR=2.26, 95%CI 1.66-3.09), advanced tumor staging (OR=0.41, 95%CI 0.36-0.46), IPI score (OR=0.40, 95%CI 0.33-0.48), but not with bone marrow involvement (OR=1.24, 95%CI 0.85-1.81) or pathological subtype (OR=0.69, 95%CI 0.41-1.16).

Conclusion: Low LMR in peripheral blood indicates poor prognosis in patients with lymphoma. As a simple clinical indicator, peripheral blood LMR combined with existing prognostic factors can improve the accuracy of lymphoma prognosis assessment.

CHN1 is a Novel Prognostic Marker for Diffuse Large B-Cell Lymphoma

Purpose

Diffuse large B-cell lymphoma (DLBCL) is the most common B-cell malignancy. Thirty to forty percent of DLBCL patients still experience relapse or develop refractory disease even with standard immunochemotherapy, leading to a poor prognosis. Currently, although several gene-based classification methods can be used to predict the prognosis of DLBCL, some patients are still unable to be classified. This study was performed to identify a novel prognostic biomarker for DLBCL.

Patients and Methods

A total of 1850 B-cell non-Hodgkin lymphoma (B-NHL) patients in 8 independent datasets with microarray gene expression profiles were retrieved from the Gene Expression Omnibus (GEO) database and Lymphoma/Leukemia Molecular Profiling Project (LLMPP). The candidate genes were selected through three filters in a strict pipeline. Survival analysis was performed in two independent datasets of patients with both gene expression data and clinical information. Gene set enrichment analysis (GSEA) and the CIBERSORT algorithm were used to explore the biological functions of the genes.

Results

We identified 6 candidate genes associated with the clinical outcome of DLBCL patients: CHN1, CD3D, CLU, ICOS, KLRB1 and LAT. Unlike the other five genes, CHN1 has not been previously reported to be implicated in lymphoma. We also observed that CHN1 had prognostic significance in important clinical subgroups; in particular, high CHN1 expression was significantly related to good outcomes in DLBCL patients with the germinal center B-cell-like (GCB) subtype, stage III–IV, or an International Prognostic Index (IPI) score > 2. Multivariate Cox regression analysis of the two datasets showed that CHN1 was an independent prognostic factor for DLBCL. Additionally, GSEA and CIBERSORT indicated that CHN1 was correlated with cell adhesion and T cell immune infiltration.

Conclusion

Our data indicate for the first time that high CHN1 expression is associated with favorable outcomes in DLBCL patients, suggesting its potential utility as a prognostic marker in DLBCL.

Understanding the Immune-Stroma Microenvironment in B Cell Malignancies for Effective Immunotherapy

Cancers, including lymphomas, develop in complex tissue environments where malignant cells actively promote the creation of a pro-tumoral niche that suppresses effective anti-tumor effector T cell responses. Research is revealing that the tumor microenvironment (TME) differs between different types of lymphoma, covering inflamed environments, as exemplified by Hodgkin lymphoma, to non-inflamed TMEs as seen in chronic lymphocytic leukemia (CLL) or diffuse-large B-cell lymphoma (DLBCL). In this review we consider how T cells and interferon-driven inflammatory signaling contribute to the regulation of anti-tumor immune responses, as well as sensitivity to anti-PD-1 immune checkpoint blockade immunotherapy. We discuss tumor intrinsic and extrinsic mechanisms critical to anti-tumor immune responses, as well as sensitivity to immunotherapies, before adding an additional layer of complexity within the TME: the immunoregulatory role of non-hematopoietic stromal cells that co-evolve with tumors. Studying the intricate interactions between the immune-stroma lymphoma TME should help to design next-generation immunotherapies and combination treatment strategies to overcome complex TME-driven immune suppression.

Angiogenesis in Lymph Nodes Is a Critical Regulator of Immune Response and Lymphoma Growth

Tumor-induced remodeling of the microenvironment in lymph nodes (LNs) includes the formation of blood vessels, which goes beyond the regulation of metabolism, and shaping a survival niche for tumor cells. In contrast to solid tumors, which primarily rely on neo-angiogenesis, hematopoietic malignancies usually grow within pre-vascularized autochthonous niches in secondary lymphatic organs or the bone marrow. The mechanisms of vascular remodeling in expanding LNs during infection-induced responses have been studied in more detail; in contrast, insights into the conditions of lymphoma growth and lodging remain enigmatic. Based on previous murine studies and clinical trials in human, we conclude that there is not a universal LN-specific angiogenic program applicable. Instead, signaling pathways that are tightly connected to autochthonous and infiltrating cell types contribute variably to LN vascular expansion. Inflammation related angiogenesis within LNs relies on dendritic cell derived pro-inflammatory cytokines stimulating vascular endothelial growth factor-A (VEGF-A) expression in fibroblastic reticular cells, which in turn triggers vessel growth. In high-grade B cell lymphoma, angiogenesis correlates with poor prognosis. Lymphoma cells immigrate and grow in LNs and provide pro-angiogenic growth factors themselves. In contrast to infectious stimuli that impact on LN vasculature, they do not trigger the typical inflammatory and hypoxia-related stroma-remodeling cascade. Blood vessels in LNs are unique in selective recruitment of lymphocytes via high endothelial venules (HEVs). The dissemination routes of neoplastic lymphocytes are usually disease stage dependent. Early seeding via the blood stream requires the expression of the homeostatic chemokine receptor CCR7 and of L-selectin, both cooperate to facilitate transmigration of tumor and also of protective tumor-reactive lymphocytes via HEV structures. In this view, the HEV route is not only relevant for lymphoma cell homing, but also for a continuous immunosurveillance. We envision that HEV functional and structural alterations during lymphomagenesis are not only key to vascular remodeling, but also impact on tumor cell accessibility when targeted by T cell-mediated immunotherapies.

MiRNA-340-5p mediates the functional and infiltrative promotion of tumor-infiltrating CD8+ T lymphocytes in human diffuse large B cell lymphoma

Background

CD8⁺ tumor-infiltrating T lymphocytes (T-TILs) in the tumor microenvironment (TME) play an important role in tumor development, and miRNAs regulate tumor cell interactions with the microenvironment. T-TIL-based tumor immunotherapy provides a promising treatment strategy in diffuse large B-cell lymphoma (DLBCL). MiRNAs tend to be attractive targets for novel antitumor interventions.

Methods

Weighted gene coexpression network analysis (WGCNA), CIBERSORT analysis and Cox regression analysis were used to identify CD8⁺ T-TIL-related miRNAs. RT-PCR, western blotting, immunohistochemistry (IHC), in situ hybridization (ISH), luciferase reporter assay, coimmunoprecipitation and ubiquitination analyses were used to detect miRNA, mRNA and protein expression and their combination. The viability and function of CD8⁺ T cells after stimulation were evaluated by enzyme-linked immunosorbent assay (ELISA), cytotoxicity assay, functional avidity assessment, flow cytometry and Cell Counting Kit-8 (CCK-8) assay. DLBCL cell lines, primary cells and a murine xenograft model established with A20 cell injection were used as in vitro and in vivo experimental models.

Results

MiR-340-5p was positively correlated with CD8⁺ T-TILs in DLBCL patients, and KMT5A was a direct target gene of miR-340-5p. CD8⁺ T-cell function was significantly enhanced by miR-340-5p mimics both in vitro and in vivo, which was reversed by KMT5A overexpression. We demonstrated that COP1/CD73 was involved in the downstream mechanism of the miR-340-5p/KMT5A axis involving ubiquitination. In vivo, we validated an improved CD8⁺ T-TIL infiltration rate and tumor suppression with miR-340-5p treatment. Furthermore, miR-340-5p directly regulated the biological activity of DLBCL cells without CD8⁺ T-cell participation.

Conclusions

MiR-340-5p promoted CD8⁺ T-TIL infiltration and antitumor function by regulating KMT5A and COP1 and further activating CD73 ubiquitination. MiR-340-5p is potentially a novel target for DLBCL immunotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-020-01752-2.

Inflammatory Cells in Diffuse Large B Cell Lymphoma

Diffuse large B cell lymphoma (DLBCL), known as the most common non-Hodgkin lymphoma (NHL) subtype, is characterized by high clinical and biological heterogeneity. The tumor microenvironment (TME), in which the tumor cells reside, is crucial in the regulation of tumor initiation, progression, and metastasis, but it also has profound effects on therapeutic efficacy. The role of immune cells during DLBCL development is complex and involves reciprocal interactions between tumor cells, adaptive and innate immune cells, their soluble mediators and structural components present in the tumor microenvironment. Different immune cells are recruited into the tumor microenvironment and exert distinct effects on tumor progression and therapeutic outcomes. In this review, we focused on the role of macrophages, Neutrophils, T cells, natural killer cells and dendritic cells in the DLBCL microenvironment and their implication as target for DLBCL treatment. These new therapies, carried out by the induction of adaptive immunity through vaccination or passive of immunologic effectors delivery, enhance the ability of the immune system to react against the tumor antigens inducing the destruction of tumor cells.

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

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

New Insights into Diffuse Large B-Cell Lymphoma Pathobiology

Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma (NHL), accounting for about 40% of all cases of NHL. Analysis of the tumor microenvironment is an important aspect of the assessment of the progression of DLBCL. In this review article, we analyzed the role of different cellular components of the tumor microenvironment, including mast cells, macrophages, and lymphocytes, in the tumor progression of DLBCL. We examined several approaches to confront the available pieces of evidence, whereby three key points emerged. DLBCL is a disease of malignant B cells spreading and accumulating both at nodal and at extranodal sites. In patients with both nodal and extranodal lesions, the subsequent induction of a cancer-friendly environment appears pivotal. The DLBCL cell interaction with mature stromal cells and vessels confers tumor protection and inhibition of immune response while delivering nutrients and oxygen supply. Single cells may also reside and survive in protected niches in the nodal and extranodal sites as a source for residual disease and relapse. This review aims to molecularly and functionally recapitulate the DLBCL–milieu crosstalk, to relate niche and pathological angiogenic constitution and interaction factors to DLBCL progression.

Immunohistochemical Markers of Tumor Microenvironment as Prognostic Predictors in Diffuse Large B-Cell Lymphoma: Study from an Oncology Centre in South India

Introduction Diffuse large B-cell lymphoma (DLBCL) accounts for 60% of lymphomas in India. Although the survival of DLBCL patients has improved following the addition of rituximab, a subset of patients do not respond well to therapy. Among the several factors responsible for this varied response, tumor microenvironment is considered to be crucial. This study is a search for such prognostic markers in the tumor microenvironment.

Materials and Methods A total of 97 patients were selected, of whom 34 were treated with the CHOP regimen and 63 with RCHOP. Immunohistochemistry for CD68 was performed to study the stromal-1 signature and CD34 for stromal-2 signature.

Results There was a significant increase in the counts of CD68-positive cells among patients free of events. CD34 count was higher in patients with events in both CHOP and RCHOP groups.

Conclusion Additional assessment of stromal microenvironment along with the cell of origin might predict the clinical outcome better in DLBCL.

Sex-Specific Differences in Primary CNS Lymphoma

Sex-specific differences have been increasingly recognized in many human diseases including brain cancer, namely glioblastoma. Primary CNS lymphoma (PCNSL) is an exceedingly rare type of brain cancer that tends to have a higher incidence and worse outcomes in male patients. Yet, relatively little is known about the reasons that contribute to these observed sex-specific differences. Using a population-representative cohort of patients with PCNSL with dense magnetic resonance (MR) imaging and digital pathology annotation (n = 74), we performed sex-specific cluster and survival analyses to explore possible associations. We found three prognostically relevant clusters for females and two for males, characterized by differences in (i) patient demographics, (ii) tumor-associated immune response, and (iii) MR imaging phenotypes. Upon a multivariable analysis, an enhanced FoxP3+ lymphocyte-driven immune response was associated with a shorter overall survival particularly in female patients (HR 1.65, p = 0.035), while an increased extent of contrast enhancement emerged as an adverse predictor of outcomes in male patients (HR 1.05, p < 0.01). In conclusion, we found divergent prognostic constellations between female and male patients with PCNSL that suggest differential roles of tumor-associated immune response and MR imaging phenotypes. Our results further underline the importance of continued sex-specific analyses in the field of brain cancer.

The Tumor Microenvironment of DLBCL in the Computational Era

Among classical exemplifications of tumor microenvironment (TME) in lymphoma pathogenesis, the “effacement model” resembled by diffuse large B cell lymphoma (DLBCL) implies strong cell autonomous survival and paucity of non-malignant elements. Nonetheless, the magnitude of TME exploration is increasing as novel technologies allow the high-resolution discrimination of cellular and extra-cellular determinants at the functional, more than morphological, level. Results from genomic-scale studies and recent clinical trials revitalized the interest in this field, prompting the use of new tools to dissect DLBCL composition and reveal novel prognostic association. Here we revisited major controversies related to TME in DLBCL, focusing on the use of bioinformatics to mine transcriptomic data and provide new insights to be translated into the clinical setting.

Tumor Microenvironment in Diffuse Large B-Cell Lymphoma: Role and Prognosis

Diffuse large B-cell lymphoma (DLBCL) represents 30-40% of all non-Hodgkin lymphomas (NHL) and is a disease with an aggressive behavior. Because about one-third of DLBCL patients will be refractory or resistant to standard therapy, several studies focused on identification of new individual prognostic and risk stratification biomarkers and new potential therapeutic targets. In contrast to other types of cancers like carcinomas, where tumor microenvironment was widely investigated, its role in DLBCL pathogenesis and patient survival is still poorly understood, although few studies had promising results. The composition of TME and its interaction with neoplastic cells may explain the role of several genes (beta2-microglobulin gene, CD58 gene), receptor-like programmed cell death-1 (PD-1) and its ligand (PD-L1), or other cell components (Treg) in tumor evasion of immune surveillance, resulting in tumor progression. Also, it was found that “gene expression profile” of the microenvironmental cells, the phenotype of tumor-associated macrophages (TAM), the expression of matricellular proteins like SPARC and fibronectin, the overexpression of several types of matrix metalloproteinases (MMPs) like MMP-2 and MMP-9, or the tissue inhibitors of matrix metalloproteinases (TIMPs) may lead to a favorable or adverse outcome. With this review, we try to highlight the influence of microenvironment components over lymphoid clone progression and their prognostic impact in DLBCL patients.

The prognostic value of tumour-associated macrophages in Non-Hodgkin's lymphoma: A systematic review and meta-analysis

Tumour-associated macrophages (TAMs) play an important role in the tumour environment and were reported to be associated with poor prognosis in several tumours. However, the prognostic significance of TAMs in Non-Hodgkin's Lymphoma (NHL) remains controversial. Consequently, we aimed to evaluate the relationship between subpopulations of TAMs and clinical outcomes in NHL patients. We did a comprehensive search of the PubMed, elsevier ScienceDirect, and Cochrane databases and extracted hazard ratio (HR) and their corresponding 95% confidence intervals (95% CIs) from eligible studies. Pooling total effect value by the stata statistical software and analysing correlation of TAMs with overall survival (OS) and progression-free survival (PFS). Furthermore, subgroup analysis and sensitivity analysis were also conducted. We deemed eleven studies, including 1211 NHL patients. Our study demonstrated that high-density CD68⁺ TAMs are associated with poor OS (HR: 1.17; 95% CI, 0.81-1.54; P = .000) and poor PFS (HR: 1.15; 95% CI, 0.63-1.67; P = .000) compared with low-density CD68⁺ TAMs in the tumour microenvironment. Similarly, high-density CD163⁺ TAMs can also predict poor OS (HR: 1.52; 95% CI, 1.11-1.92; P = .000) and shorter PFS (HR: 1.52; 95% CI, 0.73-2.30; P = .000). In addition, the high CD163⁺ /CD68⁺ TAMs ratio is significantly correlated with poor OS (HR: 3.59; 95% CI, 0.77-6.40; P = .013). However, in our subgroup analysis, high-density CD68⁺ TAMs in the tumour microenvironment is associated with better OS (HR: 0.75; 95% CI, 0.41-1.09; P = .000) in NHL patients treated with rituximab chemotherapy. Our results suggest that TAMs are a robust predictor of outcomes in NHL.

Tumor-associated macrophages predict prognosis in diffuse large B-cell lymphoma and correlation with peripheral absolute monocyte count

Background

Diffuse large B-cell lymphoma (DLBCL) is characterized by its clinical and biological heterogeneity. The clinical prognostic implications of tumor-associated macrophages (TAMs) in DLBCL remain controversial and the correlation between TAMs and peripheral absolute monocyte count (AMC) has not yet been elucidated.

Methods

In 221 untreated, newly diagnosed patients with DLBCL, we evaluated the prognostic value of TAMs using immunohistochemical analysis, as well as the association of TAMs and AMC.

Results

We found that high CD68 or high CD163 expression was correlated with clinicopathological characteristics, high CD163 expression was an adverse predictor for both overall survival (OS) [hazard ratio (HR) = 2.265, P = 0.005] and progression- free survival (PFS) (HR = 1.925, P = 0.017) in patients with DLBCL. Patients with high CD68 or high CD163 expression had significantly poorer OS and PFS than those with low CD68 or low CD163 expression, respectively (CD68: OS: P<0.001, PFS: P<0.001; CD163: OS: P<0.001, PFS: P<0.001), even in the rituximab era. Moreover, high-risk patients could be further identified by the expression of CD68 or CD163, especially in those classified as low/intermediate risk by International Prognostic Index (IPI). Furthermore, the significant positive correlation was also detected between CD68 expression or CD163 expression and AMC (r = 0.256, P<0.001; r = 0.303, P<0.001).

Conclusions

Patients with high expression of TAMs tend to have poorer OS and PFS, even in the rituximab era, and have positive correlation with AMC. Therefore, the peripheral AMC is a useful prognostic marker reflecting the status of the tumor microenvironment (TME) in DLBCL.

A novel lymphoma-associated macrophage interaction signature (LAMIS) provides robust risk prognostication in diffuse large B-cell lymphoma clinical trial cohorts of the DSHNHL

Diffuse large B-cell lymphoma (DLBCL) is a disease with heterogeneous outcome. Stromal signatures have been correlated to survival in DLBCL. Their use, however, is hampered by the lack of assays for formalin-fixed paraffin-embedded material (FFPE). We constructed a lymphoma-associated macrophage interaction signature (LAMIS) interrogating features of the microenvironment using a NanoString assay applicable to FFPE. The clinical impact of the signature could be validated in a cohort of 466 patients enrolled in prospective clinical trials of the German High-Grade Non-Hodgkin Lymphoma Study Group (DSHNHL). Patients with high expression of the signature (LAMIS^high) had shorter EFS, PFS, and OS. Multivariate analyses revealed independence from IPI factors in EFS (HR 1.7, 95% CI 1.2-2.4, p-value = 0.001), PFS (HR 1.8, 95% CI 1.2-2.5, p-value = 0.001) and OS (HR 1.8, 95% CI 1.3-2.7, p-value = 0.001). Multivariate analyses adjusted for the IPI factors showed the signature to be independent from COO, MYC rearrangements and double expresser status (DE). LAMIS^high and simultaneous DE status characterized a patient subgroup with dismal prognosis and early relapse. Our data underline the importance of the microenvironment in prognosis. Combined analysis of stromal features, the IPI and DE may provide a new rationale for targeted therapy.

Expression of IL-34 correlates with macrophage infiltration and prognosis of diffuse large B-cell lymphoma

Objectives

Infiltration of macrophages through the tyrosine kinase receptor CSF1R is a poor prognosis factor in various solid tumors. Indeed, these tumors produce CSF1R ligand, macrophage colony‐stimulating factor (M‐CSF) or interleukin‐34 (IL‐34). However, the significance of these cytokines, particularly, the newly discovered IL‐34 in haematological malignancies, is not fully understood. We therefore analysed the role of IL‐34 in diffuse large B‐cell lymphoma (DLBCL), the most common subtype of malignant lymphoma.

Methods

We analysed formalin‐fixed paraffin‐embedded lymphoma tissues of 135 DLBCL patients for the expression of IL‐34 and the number of macrophages, and the survival of these patients. The expression of IL‐34 in DLBCL cell lines and the activity of IL‐34 to induce the migration of monocytic cells were also characterised.

Results

Several lymphoma tissues showed a clear IL‐34 signal, and such signal was detectable in 36% of patients. DLBCL cell lines also expressed IL‐34. Interestingly, the percentage of IL‐34⁺ patients in the activated B‐cell subtype was significantly higher than that in the germinal centre B‐cell subtype. More interestingly, IL‐34⁺ patients showed shorter survival periods and higher number of macrophages in lymphoma tissues. The recruitment of monocytes is likely the first step for the higher macrophage density in the IL‐34⁺ lymphoma tissues. Indeed, IL‐34 induced the migration of monocytic cells.

Conclusion

Our results raise the possibility that IL‐34 in lymphoma tissues of DLBCL patients recruits monocytes, leading to the higher number of macrophages in the tissues and poor prognosis of patients. IL‐34 may be an additional therapeutic target of DLBCL.

Automated macrophage counting in DLBCL tissue samples: a ROF filter based approach

BACKGROUND

For analysis of the tumor microenvironment in diffuse large B-cell lymphoma (DLBCL) tissue samples, it is desirable to obtain information about counts and distribution of different macrophage subtypes. Until now, macrophage counts are mostly inferred from gene expression analysis of whole tissue sections, providing only indirect information. Direct analysis of immunohistochemically (IHC) fluorescence stained tissue samples is confronted with several difficulties, e.g. high variability of shape and size of target macrophages and strongly inhomogeneous intensity of staining. Consequently, application of commercial software is largely restricted to very rough analysis modes, and most macrophage counts are still obtained by manual counting in microarrays or high power fields, thus failing to represent the heterogeneity of tumor microenvironment adequately.

METHODS

We describe a Rudin-Osher-Fatemi (ROF) filter based segmentation approach for whole tissue samples, combining floating intensity thresholding and rule-based feature detection. Method is validated against manual counts and compared with two commercial software kits (Tissue Studio 64, Definiens AG, and Halo, Indica Labs) and a straightforward machine-learning approach in a set of 50 test images. Further, the novel method and both commercial packages are applied to a set of 44 whole tissue sections. Outputs are compared with gene expression data available for the same tissue samples. Finally, the ROF based method is applied to 44 expert-specified tumor subregions for testing selection and subsampling strategies.

RESULTS

Among all tested methods, the novel approach is best correlated with manual count (0.9297). Automated detection of evaluation subregions proved to be fully reliable. Comparison with gene expression data obtained for the same tissue samples reveals only moderate to low correlation levels. Subsampling within tumor subregions is possible with results almost identical to full sampling. Mean macrophage size in tumor subregions is 152.5±111.3 μm2.

CONCLUSIONS

ROF based approach is successfully applied to detection of IHC stained macrophages in DLBCL tissue samples. The method competes well with existing commercial software kits. In difference to them, it is fully automated, externally repeatable, independent on training data and completely documented. Comparison with gene expression data indicates that image morphometry constitutes an independent source of information about antibody-polarized macrophage occurence and distribution.

Dysregulation of Cell Survival in Diffuse Large B Cell Lymphoma: Mechanisms and Therapeutic Targets

Diffuse large B cell lymphoma (DLBCL) is the most common type of lymphoma worldwide, representing 30-40% of non-Hodgkin lymphomas, and is clinically aggressive. Although more than half of patients with DLBCL are cured by using standard first-line immunochemotherapy, the remaining patients are refractory to the first-line therapy or relapse after complete remission and these patients require novel therapeutic approaches. Understanding the pathogenesis of DLBCL is essential for identifying therapeutic targets to tackle this disease. Cell survival dysregulation, a hallmark of cancer, is a characteristic feature of DLBCL. Intrinsic signaling aberrations, tumor microenvironment dysfunction, and viral factors can all contribute to the cell survival dysregulation in DLBCL. In recent years, several novel drugs that target abnormal cell survival pathways, have been developed and tested in clinical trials of patients with DLBCL. In this review, we discuss cell survival dysregulation, the underlying mechanisms, and how to target abnormal cell survival therapeutically in DLBCL patients.

The Role of Macrophage/B-Cell Interactions in the Pathophysiology of B-Cell Lymphomas

Macrophages (MPs) are heterogeneous, multifunctional, myeloid-derived leukocytes that are part of the innate immune system, playing wide-ranging critical roles in basic biological activities, including maintenance of tissue homeostasis involving clearance of microbial pathogens. Tumor-associated MPs (TAMs) are MPs with defined specific M2 phenotypes now known to play central roles in the pathophysiology of a wide spectrum of malignant neoplasms. Also, TAMs are often intrinsic cellular components of the essential tumor microenvironment (TME). In concert with lymphoid-lineage B and T cells at various developmental stages, TAMs can mediate enhanced tumor progression, often leading to poor clinical prognosis, at least partly through secretion of chemokines, cytokines, and various active proteases shown to stimulate tumor growth, angiogenesis, metastasis, and immunosuppression. Researchers recently showed that TAMs express certain key checkpoint-associated proteins [e.g., programmed cell death protein 1 (PD-1), programmed cell death-ligand 1 (PD-L1)] that appear to be involved in T-cell activation and that these proteins are targets of other specific checkpoint-blocking immunotherapies (anti-PD-1/PD-L1) currently part of new therapeutic paradigms for chemotherapy-resistant neoplasms. Although much is known about the wide spectrum and flexibility of MPs under many normal and neoplastic conditions, relatively little is known about the increasingly important interactions between MPs and B-lymphoid cells, particularly in the TME in patients with aggressive B-cell non-Hodgkin lymphoma (NHL-B). Normal and neoplastic lymphoid and myeloid cell/MP lineages appear to share many primitive cellular characteristics as well as transcriptional factor interactions in human and animal ontogenic studies. Such cells are capable of ectopic transcription factor-induced lineage reprogramming or transdifferentiation from early myeloid/monocytic lineages to later induce B-cell lymphomagenesis in experimental in vivo murine systems. Close cellular interactions between endogenous clonal neoplastic B cells and related aberrant myeloid precursor cells/MPs appear to be important interactive components of aggressive NHL-B that we discuss herein in the larger context of the putative role of B-cell/MP cellular lineage interactions involved in NHL-B pathophysiology during ensuing lymphoma development.

Lymphocyte-to-monocyte ratio is associated with prognosis of diffuse large B-cell lymphoma: correlation with CD163 positive M2 type tumor-associated macrophages, not PD-1 positive tumor-infiltrating lymphocytes

The research aims to examine the prognostic value of the lymphocyte-to-monocyte ratio (LMR), neutrophil-to- lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) in diffuse large B-cell lymphoma (DLBCL). The relation of these hematologic indicators to poor antitumor immunity and prognosis must be investigated. Clinicopathologic data and survival information of 355 patients with DLBCL was retrospectively analyzed. Univariate analysis revealed that lower LMR (<2.71), higher NLR (≥2.81), CD163+ M2 tumor-associated macrophages (TAM) content ≥9.5% and programmed cell death 1 (PD-1)+ tumor-infiltrating lymphocytes (TILs) content < 4.5 cells per high power field(HPF) were significantly related to unfavorable overall survival (OS) and progression free survival (PFS). When considering the prognostic indexes of IPI, multivariate analysis confirmed that LMR of <2.71 and CD163⁺ M2 TAM content ≥9.5% significantly affected the prognosis of DLBCL. Spearman correlation test showed LMR was negatively correlated with CD163⁺ M2 TAM content. However, there were no correlation was found between LMR and PD-1+ TIL as well as between NLR and PD-1+ TIL content. These results indicated that decreased LMR lead to a weak anti-tumor immunity and could be used as a bad prognosis biomarker of DLBCL.

Mechanisms of Hypercalcemia in Non-Hodgkin Lymphoma and Associated Outcomes: A Retrospective Review

INTRODUCTION

The etiology of hypercalcemia in non-Hodgkin lymphoma (NHL) has been most often attributed to either elevated serum levels of 1,25-dihydroxycholecalciferol (calcitriol) or parathyroid-related protein (PTHrP). In a single-center retrospective review, we evaluated the incidence of, and outcomes associated with, hypercalcemia in NHL.

PATIENTS AND METHODS

The medical records of patients with a histologically confirmed diagnosis of NHL and ≥ 1 episode of hypercalcemia were evaluated for demographic and lymphoma-specific factors, including the response to therapy and overall survival.

RESULTS

Fifty-four patients with NHL met the inclusion criteria. Most patients (57.4%) had diffuse large B-cell lymphoma, of which, 70% were the nongerminal center subtype. Approximately one half (42.6%) of the included patients had undergone serologic investigation into the etiology of hypercalcemia; however, only 17 patients (31.5%) had both a serum PTHrP and a calcitriol level properly collected. Of the 17 cases for which both a serum calcitriol and a PTHrP were collected, most (61.1%) were found to have neither an elevation of serum calcitriol nor an elevation of PTHrP. The degree of calcitriol elevation correlated with worse progression-free survival (P = .04) but not overall survival.

CONCLUSION

The major mechanism by which NHL patients develop hypercalcemia is not mediated by calcitriol or PTHrP. Hypercalcemia is most prevalent in patients with diffuse large B-cell lymphoma of the nongerminal cell subtype. Patients with calcitriol-mediated hypercalcemia showed a trend toward worse outcomes, suggesting that calcitriol might be a marker of high-grade lymphoma, transformation to such, or a surrogate for more advanced disease.

Monocyte chemoattractant protein 1 expression and proliferation in primary central nervous system lymphoma

Whether the poor prognosis of primary central nervous system lymphoma (PCNSL) compared with systemic diffuse large B cell lymphoma (DLBCL) is attributable to the immune privilege of the intracerebral location or to intrinsic differences in the biological characteristics of two types of lymphoma remains unclear. Monocyte chemoattractant protein 1 (MCP-1) is essential to support tumor cell survival and growth, and the present study aimed to compare MCP-1 expression in PCNSL and peripheral DLBCL. The present study included 19 patients with PCNSL and 16 patients with DLBCL, all of whom had tissue diagnosis and lymphoma tissue samples available for analysis. Histology included immunohistochemistry using antibodies against a panel of lymphoma markers, antibodies specific to MCP-1, and antibodies specific to tumor-associated macrophages. MCP-1 expression was quantified using immunostaining scoring. RNA extraction and reverse transcription-quantitative polymerase chain reaction were used to determine MCP-1 mRNA expression. In addition, a human brain-derived lymphoma cell line, HKBML, was stimulated with MCP-1 and cell proliferation was measured by 5-bromo-2′-deoxyuridine incorporation. The expression levels of MCP-1 mRNA and MCP-1 protein were significantly increased in PCNSL compared with peripheral DLBCL. MCP-1 induced tyrosine phosphorylation of mitogen-activated protein kinase in HKBML cells, as analyzed by western blotting. The results of the present study indicated that MCP-1 expression in PCNSL promoted cell proliferation in an autocrine manner.

Implications of infiltrating immune cells within bone marrow of patients with diffuse large B-cell lymphoma

The implications of infiltrating immune cells, especially T cells and macrophages, in the bone marrow (BM) microenvironment of patients with diffuse large B-cell lymphoma (DLBCL) have rarely been studied. We aimed to investigate the significance of infiltrating immune cells in the BM microenvironment as a prognostic factor for DLBCL patients. Using the initial pretreatment BM biopsy obtained from 198 DLBCL patients, we semiquantitatively evaluated CD3+ T cells, CD8+ T cells, and CD163+ macrophages that infiltrate into the paratrabecular and interstitial areas of BM by immunohistochemistry and analyzed their clinicopathological and prognostic implications. Levels of infiltrating CD3+ T cells, CD8+ T cells, and CD163+ macrophages were significantly higher in BM with DLBCL involvement (BMI-positive group) than in that without DLBCL involvement (BMI-negative group). Infiltration of CD8+ T cells significantly increased in cases with advanced Ann Arbor stage, elevated lactate dehydrogenase level, extranodal site involvement ≥2 sites, higher Eastern Cooperative Oncology Group performance status, and higher International Prognostic Index (IPI) risk. High levels of CD3+ T cells were significantly associated with age ≤60, and high levels of CD163+ macrophages were associated with advanced Ann Arbor stage and higher IPI risk. High infiltration of CD8+ T cells was significantly related to inferior overall and recurrence-free survival rate, even in the BMI-negative group. High infiltration of CD8+ T cells within the pretreatment BM was related to poor prognosis, and might be a useful prognostic factor of DLBCL patients. Therefore, evaluation of CD8+ T cells is helpful for predicting prognosis in initial pretreatment BM biopsy of DLBCL patients.

Tumor-Associated Macrophages Can Contribute to Antitumor Activity through FcγR-Mediated Processing of Antibody-Drug Conjugates

The primary mechanism of antibody-drug conjugates (ADC) is targeted delivery of a cytotoxic payload to tumor cells via cancer-associated membrane receptors. However, the tumor microenvironment likely plays a role in ADC penetration, distribution, and processing and thus impacts the overall antitumor activity. Here, we report on the potential contribution of Fc-FcγR interactions between ADCs and tumor-associated macrophages (TAM) to the preclinical antitumor activities of ADCs. In the CD30⁺ L-428 Hodgkin lymphoma model, anti-CD30-vcMMAE and a non-binding control (hIgG-vcMMAE) demonstrated similar antitumor activity as well as similar payload release in the tumors. IHC analysis revealed L-428 tumors contained highly abundant TAMs, which were confirmed to bind ADCs by IHC and flow cytometry. The infiltration of TAMs was further found to correlate with the antitumor activity of the non-binding hIgG-vcMMAE in five additional xenograft models. hIgG1V1-vcMMAE, bearing a mutation in the Fc region which ablates Fc gamma receptor (FcγR) binding, lost antitumor activity in three TAM-high xenograft models, suggesting Fc-FcγR interactions modulate the TAM-ADC interaction. Our results suggest that TAMs can contribute to ADC processing through FcγR interaction in preclinical tumor models and may represent an important additional mechanism for drug release from ADCs. Correlative studies in clinical trials will further shed light on whether TAMs play a role in patients' response to ADC therapies. Mol Cancer Ther; 16(7); 1347-54. ©2017 AACR.

Pro-Tumoral Inflammatory Myeloid Cells as Emerging Therapeutic Targets

Since the observation of Virchow, it has long been known that the tumor microenvironment constitutes the soil for the infiltration of inflammatory cells and for the release of inflammatory mediators. Under certain circumstances, inflammation remains unresolved and promotes cancer development. Here, we review some of these indisputable experimental and clinical evidences of cancer related smouldering inflammation. The most common myeloid infiltrate in solid tumors is composed of myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs). These cells promote tumor growth by several mechanisms, including their inherent immunosuppressive activity, promotion of neoangiogenesis, mediation of epithelial-mesenchymal transition and alteration of cellular metabolism. The pro-tumoral functions of TAMs and MDSCs are further enhanced by their cross-talk offering a myriad of potential anti-cancer therapeutic targets. We highlight these main pro-tumoral mechanisms of myeloid cells and give a general overview of their phenotypical and functional diversity, offering examples of possible therapeutic targets. Pharmacological targeting of inflammatory cells and molecular mediators may result in therapies improving patient condition and prognosis. Here, we review experimental and clinical findings on cancer-related inflammation with a major focus on creating an inventory of current small molecule-based therapeutic interventions targeting cancer-related inflammatory cells: TAMs and MDSCs.

New Mechanisms of Tumor-Associated Macrophages on Promoting Tumor Progression: Recent Research Advances and Potential Targets for Tumor Immunotherapy

The majority of basic and clinical studies have shown a protumor function of tumor-associated macrophages (TAMs), which represent a large proportion of matrix cells. TAMs promote tumorigenesis, and their number is related to the malignancy degree and poor prognosis of many kinds of tumors. Macrophage plasticity makes it possible to change the tumor microenvironment and remodel antitumor immunity during cancer immunotherapy. Increasing numbers of studies have revealed the effects of TAMs on the tumor microenvironment, for example, via promotion of tumor growth and tumorigenesis and through an increase in the number of cancer stem cells or via facilitation of angiogenesis, lymphangiogenesis, and metastasis. Investigators also proposed tumor-immunological treatments targeting TAMs by inhibiting TAM recruitment and differentiation, by regulating TAM polarization, and by blocking factors and pathways associated with the protumor function of TAMs. This comprehensive review presents recent research on TAMs in relation to prediction of poor outcomes, remodeling of the tumor immune microenvironment, and immunological targeted therapies.

Role of tumor-associated macrophages in human malignancies: friend or foe?

Tumor-associated macrophages (TAMs) play a pivotal role in tumor growth in human malignancies. Published studies have analyzed the relationship between TAM infiltration and the prognosis of patients for many human tumors. Most studies reported a positive correlation between TAM density and a poor prognosis. Studies focusing on macrophage phenotypes emphasized the protumor role of M2 anti-inflammatory macrophages in many types of human tumors. However, TAMs influence tumor progression in various ways that depend on differences in tumor sites, histology, and microenvironments. In this review, we summarize the function of TAMs in various human malignancies by reviewing the data provided in studies of TAMs in human malignancies.

Prediction of survival of diffuse large B-cell lymphoma patients via the expression of three inflammatory genes

Currently, several gene-expression signatures that were used to predict survival of diffuse large B-cell lymphoma (DLBCL) patients, showed a restriction on the practical work for lack of convenient operation. In this study, we screened inflammatory genes whose expression correlated with survival of DLBCL and established a predictive model including IL6, IL1A and CSF3 through multivariate Cox regression based on the expression of these three genes. We validated the model at protein level in our clinical serum cohort composed of 101 patients of DLBCL and 50 healthy controls and 534 DLBCL patients at mRNA level from three independent Gene Expression Omnibus (GEO) data sets. We found our model to be independent of the International Prognostic Index (IPI), moreover, it can augment the predictive power of IPI. In summary, our three-gene model is sufficient to predict survival of DLBCL patients via measuring the concentration of three inflammatory cytokines in peripheral blood.

High numbers of CD68+ tumor-associated macrophages correlate with poor prognosis in extranodal NK/T-cell lymphoma, nasal type

Many studies have demonstrated that tumor-associated macrophages (TAMs) were a prognostic indicator in patients with B cell lymphoma. But, we know little about the clinical significance of TAMs in extranodal natural killer/T cell lymphoma(ENKTL), nasal type. CD68 expression was detected using immunohistochemistry to determine the numbers of TAMs in 70 ENKTL patients, and the data were used to evaluate its relationship with clinicopathological features, treatment response, and prognosis. Patients with high number of infiltrated CD68+ TAMs (>60/hpf) at diagnosis tended to have more adverse clinical characteristics. Patients with low CD68+ TAM content (<60/hpf) at diagnosis had better overall survival (P = 0.003) and progression-free survival (P = 0.002) and achieved higher complete remission rates (P = 0.008). Multivariate analysis revealed that CD68 + TAM content, Ki-67 index, and stage III and IV were independent prognostic factors for both OS and PFS. Using the International Prognostic Index or Korean Prognostic Index for extranodal NK/T cell lymphoma, nasal type, the majority of patients were in the low-risk category. CD68 + TAM content was helpful to differentiate the low-risk patients with different survival outcomes. Our data suggest that CD68+ TAM content at diagnosis is a powerful predictor of prognosis for ENKTL, which suggests a role for TAMs in the pathogenesis of this disease and offers new insight into potential therapeutic strategies.

Prognostic effect of Ki-67 expression in rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone-treated diffuse large B-cell lymphoma is limited to non-germinal center B-cell-like subtype in late-elderly patients

This study evaluated the effect of age and cell of origin on the prognostic significance of Ki-67 labeling index (Ki-67 LI) on overall survival (OS) of diffuse large B-cell lymphoma (DLBCL) in a cohort of 697 patients treated with rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP). Multivariate analysis revealed no prognostic significance of high Ki-67 LI (≥ 85%) for OS. However, on subgroup analysis, high Ki-67 LI was significantly associated with poor OS in late-elderly patients (aged ≥ 70 years) (p = 0.021) and non-germinal center B-cell-like (GCB) subtype (p = 0.015). In particular, high Ki-67 LI was associated with a poor prognosis in late-elderly patients with non-GCB subtype. No correlation was observed in young adults (aged < 60 years) or early-elderly (aged 60-70 years) patients or GCB subtype. The present study shows that high Ki-67 LI is a risk factor for poor OS in the late-elderly age group and non-GCB subtype in patients with DLBCL treated with R-CHOP.

Microenvironment dependency in Chronic Lymphocytic Leukemia: The basis for new targeted therapies

Chronic Lymphocytic Leukemia (CLL) is a prototype microenvironment-dependent B-cell malignancy, in which the neoplastic B cells co-evolve together with a supportive tissue microenvironment, which promotes leukemia cell survival, growth, and drug-resistance. Chemo-immunotherapy is an established treatment modality for CLL patients, resulting in high rates of responses and improved survival, especially in low-risk CLL. New, alternative treatments target B-cell receptor (BCR) signaling and the Chemokine (C-X-C motif) Receptor 4 (CXCR4)-Chemokine (C-X-C motif) Ligand 12 (CXCL12) axis, which are key pathways of CLL-microenvironment cross talk. The remarkable clinical efficacy of inhibitors targeting the BCR-associated kinases Bruton's tyrosine kinase (BTK) and phosphoinositide 3-kinase delta (PI3Kδ) challenges established therapeutic paradigms and corroborates the central role of BCR signaling in CLL pathogenesis. In this review, we discuss the cellular and molecular components of the CLL microenvironment. We also describe the emerging therapeutic options for CLL patients, with a focus on inhibitors of CXCR4-CXCL12 and BCR signaling.

Prognostic influence of macrophages in patients with diffuse large B-cell lymphoma: a correlative study from a Nordic phase II trial

The prognostic impact of the tumor microenvironment in diffuse large B-cell lymphoma has not been systematically assessed. We analyzed mRNA and antigen expression of monocytes, macrophages, lymphocytes, dendritic and natural killer cells in pretreatment tumor samples of patients with high-risk diffuse large B-cell lymphoma using gene expression microarray and immunohistochemistry. The patients were treated in a Nordic phase II study with dose-dense chemoimmunotherapy and central nervous system prophylaxis. Of the studied markers for non-malignant inflammatory cells, CD68 expression and CD68(+) macrophage counts correlated with favorable outcome. Five-year progression-free survival rates were 83% and 43% for the patients with high and low CD68 mRNA levels, respectively (P=0.007), while overall survival rates were 83% and 64%, respectively (P=ns). The patients with high CD68(+) macrophage counts had better 5-year progression-free survival (74% versus 40%; P=0.003) and overall survival (90% versus 60%; P=0.009) than the patients with low macrophage counts. Low CD68(+) macrophage count retained its prognostic impact on overall survival with age-adjusted International Prognostic Index [RR=5.0 (95% CI 1.024-19.088); P=0.017]. The findings were validated in three independent cohorts of patients treated with chemoimmunotherapy. In contrast, in patients treated with chemotherapy, high CD68(+) macrophage count was associated with poor progression-free survival (40% versus 72%; P=0.021) and overall survival (39% versus 72%; P=0.015). Together, the data suggest that macrophages exhibit a dual, treatment-specific role in diffuse large B-cell lymphoma. For the patients treated with chemoimmunotherapy, high pretreatment CD68 mRNA levels and CD68(+) macrophage numbers predict a favorable outcome.

Microvascular density, CD68 and tryptase expression in human diffuse large B-cell lymphoma

Diffuse Large B-cell Lymphoma (DLBCL) is the most common form of Non-Hodgkin lymphoma characterized by clinical and biological heterogeneity attributable both to the tumor cells and the complex tumor-microenvironment surrounding them. Tumor-associated macrophages (TAMs) and mast cells are two major components of the tumor inflammatory infiltrate with a definite role in enhancing tumor angiogenesis. In this study, we have investigated CD68 and tryptase expression and their relationship with microvascular density (MVD) in chemo-resistant and chemosensitive patients affected by DLBCL. CD68 and tryptase expression as well as MVD were increased in chemo-resistant patients when compared with chemosensitive patients. Tryptase expression showed a positive correlation with MVD, supporting a role for mast cell in DLBCL tumor angiogenesis, while CD68 correlation with MVD was not significant, indicating a different role for TAMs than angiogenesis in DLBCL.