Lack of association of tumor-associated macrophages with clinical outcome in patients with classical Hodgkin's lymphoma

Role of CD68 in the tumor immune microenvironment in Hodgkin's lymphoma

INTRODUCTION

Despite the high rate of cure in classical Hodgkin Lymphoma (cHL), some patients experienced a refractory disease, sometimes, hardly curable. In the pathogenesis of cHL, Reed Sternberg Cells (HRSC), which represent only less than 1% of tumor cells, are not the only protagonist; in fact, the role of tumor microenvironment is essential in survival, tumor growth, and progression of the disease due to the interaction between immune cells, chemokines, and cytokines.

AREAS COVERED

In this review, the current significant literature was discussed. Many studies demonstrated the role of macrophages CD68+ as 'protumor', especially in supporting HRSC survival through cell-to-cell and paracrine interactions. Increased infiltration of CD68 macrophages correlate with a poor prognosis. This review examines the interaction between CD68 macrophages, HRSC and cHL milieu, and the consequent clinical impact, providing an up-do-date portrait of these immune cells with possible translational and therapeutic applications.

EXPERT OPINION

We can suggest that a high baseline CD68 macrophages in cHL patients could contribute to the identification of high-risk patients and help clinicians to choose the best treatment, in the context of refractory disease. A macrophage target strategy in association with chemotherapy or biological therapy could represent a promising approach for future studies and investigations.

Mesenchymal stem cells-macrophages crosstalk and myeloid malignancy

As major components of the tumor microenvironment, both mesenchymal stem cells (MSCs) and macrophages can be remodelled and exhibit different phenotypes and functions during tumor initiation and progression. In recent years, increasing evidence has shown that tumor-associated macrophages (TAMs) play a crucial role in the growth, metastasis, and chemotherapy resistance of hematological malignancies, and are associated with poor prognosis. Consequently, TAMs have emerged as promising therapeutic targets. Notably, MSCs exert a profound influence on modulating immune cell functions such as macrophages and granulocytes, thereby playing a crucial role in shaping the immunosuppressive microenvironment surrounding tumors. However, in hematological malignancies, the cellular and molecular mechanisms underlying the interaction between MSCs and macrophages have not been clearly elucidated. In this review, we provide an overview of the role of TAMs in various common hematological malignancies, and discuss the latest advances in understanding the interaction between MSCs and macrophages in disease progression. Additionally, potential therapeutic approaches targeting this relationship are outlined.

Prognostic Markers within the Tumour Microenvironment in Classical Hodgkin Lymphoma

Classical Hodgkin lymphoma (cHL) accounts for 0.4% of all new cancer cases globally. Despite high cure rates with standard treatment, approximately 15% of patients still experience relapsed or refractory (RR) disease, and many of these eventually die from lymphoma-related causes. Exciting new targeted agents such as anti-PD-1 agents and brentuximab vedotin have changed the therapeutic paradigm beyond chemotherapy and radiotherapy alone. Advances in understanding of the molecular biology are providing insights in the context of novel therapies. The signature histology of cHL requires the presence of scant malignant Hodgkin Reed-Sternberg cells (HRSCs) surrounded by a complex immune-rich tumour microenvironment (TME). The TME cellular composition strongly influences outcomes, yet knowledge of the precise characteristics of TME cells and their interactions with HRSCs is evolving. Novel high-throughput technologies and single-cell sequencing allow deeper analyses of the TME and mechanisms elicited by HRSCs to propagate growth and avoid immune response. In this review, we explore the evolution of knowledge on the prognostic role of immune cells within the TME and provide an up-to-date overview of emerging prognostic data on cHL from new technologies that are starting to unwind the complexity of the cHL TME and provide translational insights into how to improve therapy in the clinic.

Tumor-Associated Macrophages in Multiple Myeloma: Key Role in Disease Biology and Potential Therapeutic Implications

Multiple myeloma (MM) is characterized by multiple relapse and, despite the introduction of novel therapies, the disease becomes ultimately drug-resistant. The tumor microenvironment (TME) within the bone marrow niche includes dendritic cells, T-cytotoxic, T-helper, reactive B-lymphoid cells and macrophages, with a complex cross-talk between these cells and the MM tumor cells. Tumor-associated macrophages (TAM) have an important role in the MM pathogenesis, since they could promote plasma cells proliferation and angiogenesis, further supporting MM immune evasion and progression. TAM are polarized towards M1 (classically activated, antitumor activity) and M2 (alternatively activated, pro-tumor activity) subtypes. Many studies demonstrated a correlation between TAM, disease progression, drug-resistance and reduced survival in lymphoproliferative neoplasms, including MM. MM plasma cells in vitro could favor an M2 TAM polarization. Moreover, a possible correlation between the pro-tumor effect of M2 TAM and a reduced sensitivity to proteasome inhibitors and immunomodulatory drugs was hypothesized. Several clinical studies confirmed CD68/CD163 double-positive M2 TAM were associated with increased microvessel density, chemoresistance and reduced survival, independently of the MM stage. This review provided an overview of the biology and clinical relevance of TAM in MM, as well as a comprehensive evaluation of a potential TAM-targeted immunotherapy.

Unraveling the Immune Microenvironment in Classic Hodgkin Lymphoma: Prognostic and Therapeutic Implications

Classic Hodgkin lymphoma (cHL) is a lymphoid neoplasm composed of rare neoplastic Hodgkin and Reed-Sternberg (HRS) cells surrounded by a reactive tumor microenvironment (TME) with suppressive properties against anti-tumor immunity. TME is mainly composed of T cells (CD4 helper, CD8 cytotoxic and regulatory) and tumor-associated macrophages (TAMs), but the impact of these cells on the natural course of the disease is not absolutely understood. TME contributes to the immune evasion of neoplastic HRS cells through the production of various cytokines and/or the aberrant expression of immune checkpoint molecules in ways that have not been fully understood yet. Herein, we present a comprehensive review of findings regarding the cellular components and the molecular features of the immune TME in cHL, its correlation with treatment response and prognosis, as well as the potential targeting of the TME with novel therapies. Among all cells, macrophages appear to be a most appealing target for immunomodulatory therapies, based on their functional plasticity and antitumor potency.

Classic Hodgkin lymphoma with marked granulomatous reaction: A clinicopathologic study of 20 cases

Granulomatous reactions can be associated with various types of lymphoma, most commonly classic Hodgkin lymphoma (CHL). In some cases, the granulomatous reaction is extensive, obscuring the presence of neoplastic cells and potentially leading to delayed diagnosis and treatment. It is unknown if this subgroup of CHL has any unique clinicopathologic features. Here, we assessed the clinical and pathological features of 20 cases of CHL with a marked granulomatous reaction, defined in this study as granulomas representing ≥50% of the total cellularity/space of the specimen. This cohort of patients showed a male predominance (M:F ratio = 1.9:1) and 75% of patients were older than 40 years. Nineteen (95%) patients presented with lymphadenopathy with the neck/supraclavicular areas being most commonly involved (11/19; 58%). Advanced stage (III-IV) disease and B symptoms were present in 69% and 64% of patients, respectively. The morphologic features of these neoplasms fit best with mixed cellularity type. The Hodgkin and Reed-Sternberg (HRS) cells were positive for CD30, PAX5 (weak), pSTAT3 (80%), CD15 (70%), PD-L1 (67%), EBV-encoded small RNA (EBER)/LMP1 (50%) and CD20 (42%), and were negative for CD3, CD5, CD45, ALK and pERK. The histiocytes of the granulomas were positive for PD-L1 (67%), pSTAT3 (50%), and were negative for pERK and cyclin D1. Next generation sequencing using a 162-gene panel was negative for mutations in 4 cases. With a median follow-up of 58.9 months (range, 3.4-199.2 months), the median overall survival was 111 months and the 5-year overall survival was 78%. In summary, patients with CHL and a marked granulomatous reaction can present a diagnostic challenge and the pathologist must be alert to the possible presence of CHL to avert potential misdiagnosis. The histiocytes in the granulomas frequently express PD-L1, likely through the activation of the JAK/STAT pathway, suggesting a potential role for PD-1 blockade therapy in these patients.

An updated portrait of monocyte-macrophages in classical Hodgkin lymphoma

Classical Hodgkin lymphoma (cHL) is a unique neoplastic ecosystem characterized by a heterogeneous immune infiltrate surrounding the rare malignant Hodgkin Reed-Sternberg cells. Though less abundant than T-cells, tumor-infiltrating macrophages play a pivotal role in supporting HRS survival through cell-to-cell and paracrine interactions. Traditional immunohistochemistry based upon the M1-M2 dichotomy yielded controversial results about the composition, functional role and prognostic impact of macrophages in cHL. More recent studies exploiting single-cell technologies and image analyses have highlighted the heterogeneity and the peculiar spatial arrangement of the macrophagic infiltrate, with the most immunosuppressive subpopulations lying in close proximity of HRS cells and the most tumor-hostile subsets kept far away from the neoplastic niches. High-throughput analysis of peripheral blood mononuclear cells in cHL patients have also identified a novel, potentially cytotoxic, subpopulation predicting better response to PD-1 blockade. This review examines the phenotypic profile, spatial localization and clinical impact of tumor-infiltrating macrophages and circulating monocytes in cHL, providing an up-do-date portrait of these innate immune cells with possible translational applications.

Whole-slide image analysis identifies a high content of Hodgkin Reed-Sternberg cells and a low content of T lymphocytes in tumor microenvironment as predictors of adverse outcome in patients with classic Hodgkin lymphoma treated with ABVD

Classic Hodgkin lymphoma (cHL) constitutes the most frequent lymphoma in young adults. Its histopathology is unique as a scattered tumor population, termed Hodgkin Reed-Sternberg (HRS) cells is diluted in a prominent tumor microenvironment (TME) composed of T lymphocytes, B lymphocytes, macrophages, neutrophils, eosinophils and histiocytes. Traditionally, the identification of prognostic biomarkers in the cHL TME has required visual inspection and manual counting by pathologists. The advent of whole-slide imaging (WSI) and digital image analysis methods could significantly contribute to improve this essential objective in cHL research, as a 10-20% of patients are still refractory or relapsed after conventional chemotherapy. In this work, we have digitized a total of 255 diagnostic cHL slides and quantified the proportion of HRS cells (CD30), B cells (CD20) and T cells (CD3) by digital image analysis. Data obtained where then correlated with the overall survival (OS) and progression free survival (PFS) of cHL patients. Quantification of HRS cells, B cells and T cells reflects the biological heterogeneity of the different cHL histological subtypes analyzed. A percentage of 2.00% of HRS cells statistically significantly discriminated between patients achieving a complete metabolic response (CMR) and refractory or relapsed (R/R) patients both for the OS (P=0.001) and PFS (P=0.005). Furthermore, patients with a percentage of T cells below the 26.70% in the TME showed a statistically significantly shorter OS (P=0.019) and PFS (P=0.041) in comparison with patients above this threshold. A subgroup of patients with a low content of T cells and high content of HRS cells exhibited a special aggressive clinical course. Currently, there is the need to implement quantitative and easy scalable methods to enhance clinical translation, as the cHL TME plays a central role in the clinical course of the disease. The results of this study could contribute to the identification of prognostic biomarkers specifically looking at the cHL TME and their inclusion in future clinical trials.

Inflammatory microenvironment in classical Hodgkin’s lymphoma with special stress on mast cells

Classical Hodgkin’s lymphoma (CHL) accounts for 10% of all lymphomas. Nodular sclerosis and mixed cellularity accounts for nearly 80% of all CHL cases. The number of mast cells in CHL correlates with poor prognosis, is significantly higher in nodular sclerosis than in other CHL subtypes, and an association between the degree of angiogenesis and the number of intratumoral mast cells has been demonstrated in CHL. Even with the best available treatment, a significant percentage of CHL patients progress or relapse after first-line therapy. 50% of patients with disease relapse achieve subsequent long-term disease control with salvage therapies. In this context, new potential therapeutic opportunities are required, and mast cells may be regarded as a new target for adjuvant treatment of CHL through the inhibition of angiogenesis and tissue remodeling and allowing the secretion of cytotoxic cytokines.

FOXP3+/CD68+ ratio within the tumor microenvironment may serve as a potential prognostic factor in classical Hodgkin lymphoma

Classical Hodgkin lymphoma (CHL) is characterized by extensive inflammatory immune cells, which predict the disease prognosis. Therefore, this study aimed to explore the significance of different tumor-infiltrated immune cells and subpopulation ratios observed in the tumor microenvironment of CHL, particularly relating to the disease's prognosis-focusing on overall survival (OS) and event-free survival (EFS). Utilizing immunohistochemistry, the quantification and exploration of selected immune cells' subsets, including CD3+, CD4+, CD8+, FOXP3+, CD20+, and CD68+ were conducted on 102 histological samples with primary CHL. Eosinophils were pathologically assessed. Besides, we determined the ratios between different tumor-infiltrated immune cells for each patient. Kaplan-Meier method and Cox regression modeling were used for survival analysis. We demonstrated that among all ratios and immune cells individually, only a higher FOXP3+/CD68+ ratio (≥1.36 cutoff) displayed a tendency towards a favorable OS (p = 0.057, HR = 0.43 [0.18-1.02]) and EFS (p = 0.067, HR = 0.44 [0.18-1.06]) using Cox regression modeling. Moreover, the Kaplan-Meier method showed an association of a higher FOXP3+/CD68+ ratio with a longer 5-years OS (p = 0.037) and a tendency to a better EFS (p = 0.051); however, neither the combined FOXP3+ and CD68+ nor FOXP3+ or CD68+ separately was correlated to the CHL survival. Together, these results demonstrated that the FOXP3+/CD68+ ratio could predict the outcomes of CHL, providing more informative significance than FOXP3+ and CD68+ combined or FOXP3+ and CD68+ individually and might be a potential indicator of risk stratification, which has an important value for guiding the clinical treatment.

The Hodgkin Lymphoma Immune Microenvironment: Turning Bad News into Good

The classic Hodgkin lymphoma (cHL) tumor microenvironment (TME) is by far the most abundant component of tumors and is responsible for most of their biological and clinical characteristics. Recent advances in our knowledge of these networks in cellular interactions allow us to understand that the neoplastic Hodgkin and Reed Sternberg (HRS) cells, although they are in the minority, are the main architects of this dysregulated immune milieu. Here, we review the major changes that have happened in recent years: from TME as a helpless bystander, reflecting an ineffective immune response, to a dynamic tumor-promoting and immunosuppressive element. The HRS cells promote survival through interconnected intrinsic and extrinsic alterations, boosting pro-tumoral signaling pathways through genetic aberrations and autocrine growth signals, in parallel with abnormal cytokine secretion for the recruitment and selection of the best cell partners for this immunosuppressive TME. In turn, cHL is already proving to be the perfect model with which to address an immune checkpoint blockade. Preliminary data demonstrate the utility of druggable key signaling pathways in this ensemble, such as JAK-STAT, NF-κB, and others. In addition, myriad biomarkers predicting a response await validation by new in situ multiplex analytical methods, single-cell gene expression, and other techniques. Together, these components will define the functional phenotypes with which we will elucidate the molecular pathogenesis of the disease and improve the survival of patients who are refractory to conventional therapies.

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.

Checkpoint protein expression in the tumor microenvironment defines the outcome of classical Hodgkin lymphoma patients

Emerging evidence indicates a major impact for the tumor microenvironment (TME) and immune escape in the pathogenesis and clinical course of classical Hodgkin lymphoma (cHL). We used gene expression profiling (n=88), CIBERSORT, and multiplex immunohistochemistry (n=131) to characterize the immunoprofile of cHL TME, and correlated the findings with survival. Gene expression analysis divided tumors into subgroups with T cell-inflamed and non-inflamed TME. Several macrophage-related genes were upregulated in samples with the non-T cell-inflamed TME, and based on the immune cell proportions, the samples clustered according to the content of T cells and macrophages. A cluster with high proportions of checkpoint protein (PD-1, PD-L1, IDO-1, LAG-3, and TIM-3) positive immune cells translated to unfavorable overall survival (OS) (5-year OS 76% vs. 96%, P=0.010), and remained as an independent prognostic factor for OS in multivariable analysis (HR 4.34, 95% CI 1.05-17.91, P=0.043). cHLs with high proportions of checkpoint proteins overexpressed genes coding for cytolytic factors, proposing paradoxically that they were immunologically active. This checkpoint molecule gene signature translated to inferior survival in a validation cohort of 290 diagnostic cHL samples (P<0.001) and in an expansion cohort of 84 cHL relapse samples (P=0.048). Our findings demonstrate the impact of T cell- and macrophage-mediated checkpoint system on the survival of patients with cHL.

Hodgkin Lymphoma: A Special Microenvironment

Classical Hodgkin's lymphoma (cHL) is one of the most particular lymphomas for the few tumor cells surrounded by an inflammatory microenvironment. Reed-Sternberg (RS) and Hodgkin (H) cells reprogram and evade antitumor mechanisms of the normal cells present in the microenvironment. The cells of microenvironment are essential for growth and survival of the RS/H cells and are recruited through the effect of cytokines/chemokines. We summarize recent advances in gene expression profiling (GEP) analysis applied to study microenvironment component in cHL. We also describe the main therapies that target not only the neoplastic cells but also the cellular components of the background.

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.

Whole-slide image analysis of the tumor microenvironment identifies low B-cell content as a predictor of adverse outcome in patients with advanced-stage classical Hodgkin lymphoma treated with BEACOPP

Asubset of patients with advanced-stage classical Hodgkin lymphoma (cHL) relapse or progress following standard treatment. Given their dismal prognosis, identifying this group of patients upfront represents an important medical need. While prior research has identified characteristics of the tumor microenvironment, which are associated with cHL outcomes, biomarkers that are developed and validated in this high-risk group are still lacking. Here, we applied wholeslide image analysis (WSI), a quantitative, large-scale assessment of tumor composition that utilizes conventional histopathology slides. We conducted WSI on pre-treatment biopsies from 340 patients with advanced-stage cHL enrolled in the HD12 and HD15 trials of the German Hodgkin Study Group (GHSG), and tested our results in a validation cohort of 147 advanced-stage cHL patients within the GHSG HD18 trial. All patients were treated with BEACOPP-based regimens. By quantifying T cells, B cells, Hodgkin and Reed-Sternberg cells and macrophages with WSI, 80% of all cells in the tumor tissue were identified. Crucially, low B-cell count was associated with significantly reduced progression-free survival and overall survival, while the content of T cells, macrophages and Hodgkin and Reed-Sternberg cells was not associated with the risk of progression or relapse in the study cohort. We further validated low Bcell content as a prognostic factor for progression-free survival and overall survival in the validation cohort and demonstrated the good interobserver agreement of WSI. WSI may represent a key tool for risk stratification of advanced-stage cHL and can easily be added to the standard diagnostic histopathology work-up.

Classic Hodgkin lymphoma in Guatemalan children of age less than six years: analysis of immune regulatory pathways and the tumor microenvironment

Classic Hodgkin lymphoma (cHL) in young children (ages 0-6) is rare in high income countries (HICs) but is more prevalent in low- and middle-income countries (LMICs) like Guatemala. Given that the majority of cHL studies have evaluated adolescent/adults, and the immune system changes with age, we sought to characterize Epstein-Barr virus (EBV) expression, immune regulatory pathway markers and the tumor microenvironment in 42 children ages 0-6 with cHL from Guatemala. We found a very high frequency of EBV expression (97.5%). Hodgkin cells showed increased expression of PD1 ligands and CD137, indicative of shared immune regulatory mechanisms with adult cHL. Pediatric cHL also showed an increase in CD8+ tumor infiltrating lymphocytes and tumor associated macrophages within the tumor microenvironment. Despite 25 having high risk disease, only 4 patients died from progressive disease, relapse or infection.

Relationship of Tumor-Associated Macrophage Population Detected by CD68 PG-M1, CD68 KP1, and CD163 with Latent EBV Infection and Prognosis in Classical Hodgkin Lymphoma

OBJECTIVE

To evaluate the quantity of tumor-associated macrophages (TAMs) in cases of Hodgkin Lymphoma of classical type (cHL), and to reveal possible associations between TAM intensity and latent Epstein-Barr virus (EBV) infection, overall survival, progression-free survival, prognostic indices, and clinicopathological parameters.

MATERIALS AND METHODS

A total 46 cases of cHL with complete clinical records were selected and re-evaluated histopathologically. Staining for CD68 (PG-M1; KP1 clones) and CD163 was evaluated and the cut-off values were defined. Also, all cases were evaluated using the chromogen in situ hybridization (CISH) method with EBER (Epstein-Barr virus-encoded RNA) probes for the presence of possible EBV infection.

RESULTS

It was found that high expression levels of PG-M1 and high International Prognostic Scores (IPS) were associated with shortened overall survival (p=0.047, p=0.013). Cases with 2 or less areas of nodal region involvement were observed to have longer progression-free survival period (p=0.043). Higher expression levels of CD68 PG-M1, CD68 KP1, and CD163 were found to show significant associations with the presence of some clinical parameters such as the presence of B symptoms, spleen involvement, and the presence of EBV infection.

CONCLUSIONS

Our findings suggest that increase of PG-M1+ TAM is associated with shortened overall survival, while higher expressions of all immunohistochemical markers are statistically significantly associated with the presence of EBV infection and clinical parameters mentioned above. These findings indicate that highlighting the TAM rate via macrophage markers in cases of cHL could be helpful in determining the prognostic risk groups and the relevant results should be mentioned in pathology reports.

Tumor-associated macrophages in classical Hodgkin lymphoma: hormetic relationship to outcome

Commonly attributed to the prevalence of M2 macrophages, tumor-associated macrophages (TAM) are linked to poor outcome in Hodgkin lymphoma (HL). MYC is supposed to control the expression of M2-specific genes in macrophages, and deficiency in MYC-positive macrophages inhibits tumor growth in mouse models. To verify this hypothesis for HL, seventy-six samples were subjected to immunohistochemical double staining using CD68 or CD163 macrophage-specific antibodies and a reagent detecting MYC. For each cell population, labelled cells were grouped according to low, intermediate and high numbers and related to disease-free survival (DFS) and overall survival (OS). MYC+ cells accounted for 21% and 18% of CD68+ and CD163+ cells, respectively. Numbers of MYC- macrophages were significantly higher in EBV+ cases while no differences were observed for MYC+ macrophages between EBV+ and EBV- cases. Cases with highest numbers of macrophages usually showed worst DFS and OS. In most scenarios, intermediate numbers of macrophages were associated with better outcome than very low or very high numbers. Our observations are reminiscent of the "hormesis hypothesis" and suggest that a relative lack of TAM may allow HL growth while macrophages display an inhibitory effect with increasing numbers. Above a certain threshold, TAM may again support tumor growth.

Clinico-pathological significance of immunohistochemically marked tumor-associated macrophage in classic Hodgkin lymphoma

BACKGROUND

Tumor-associated macrophages (TAM) are pivotal in remodeling of the tumor immune microenvironment and clinical outcome. Herein, we aim to evaluate the impact of immunohistochemical (IHC) expression of CD68 and CD163 in TAM on clinico-pathological features, patients' response to therapy and the overall survival (OS).

RESULTS

This retrospective study was performed on paraffin-embedded tissue blocks of 100 classic Hodgkin Lymphoma (cHL) cases diagnosed and treated at our Institution. Immunohistochemical scores of CD68 and CD163 were statistically related to bulky disease (p value = 0.005 for both), tumor stage (p value = 0.02 for both), International Prognostic Score (IPS) (p value = 0.04 and 0.02 respectively), and the overall response rate (ORR) (p value = 0.001). Additionally, CD163 was also statistically related to gender (p value = 0.02), serum albumin level (p value = 0.03), and B symptoms (p value = 0.04). HCV seropositivity did not relate to either CD68 or CD163 score. Using univariate analysis revealed that B symptoms, bulky disease, IPS ≥ 3, and CD163 > 25% were associated with lower OS (p values = 0.003, 0.006, 0.001, and < 0.001 respectively), while after multivariate cox regression analysis, B symptoms, IPS ≥ 3, and CD163 > 25% were related to inferior OS (p values 0.02, 0.02, and 0.003).

CONCLUSION

CD163 expressing TAM is a powerful predictor for OS in cHL, unlike CD68.

Prognostic Impact of Tumor-Associated Macrophages on Survival Is Checkpoint Dependent in Classical Hodgkin Lymphoma

Tumor microenvironment and immune escape affect pathogenesis and survival in classical Hodgkin lymphoma (cHL). While tumor-associated macrophage (TAM) content has been associated with poor outcomes, macrophage-derived determinants with clinical impact have remained undefined. Here, we have used multiplex immunohistochemistry and digital image analysis to characterize TAM immunophenotypes with regard to expression of checkpoint molecules programmed cell death ligand 1 (PD-L1) and indoleamine 2,3-dioxygenase 1 (IDO-1) from the diagnostic tumor tissue samples of 130 cHL patients, and correlated the findings with clinical characteristics and survival. We show that a large proportion of TAMs express PD-L1 (CD68⁺, median 32%; M2 type CD163⁺, median 22%), whereas the proportion of TAMs expressing IDO-1 is lower (CD68⁺, median 5.5%; CD163⁺, median 1.4%). A high proportion of PD-L1 and IDO-1 expressing TAMs from all TAMs (CD68⁺), or from CD163⁺ TAMs, is associated with inferior outcome. In multivariate analysis with age and stage, high proportions of PD-L1⁺ and IDO-1⁺ TAMs remain independent prognostic factors for freedom from treatment failure (PD-L1⁺CD68⁺/CD68⁺, HR = 2.63, 95% CI 1.17–5.88, p = 0.019; IDO-1⁺CD68⁺/CD68⁺, HR = 2.48, 95% CI 1.03–5.95, p = 0.042). In contrast, proportions of PD-L1⁺ tumor cells, all TAMs or PD-L1⁻ and IDO-1⁻ TAMs are not associated with outcome. The findings implicate that adverse prognostic impact of TAMs is checkpoint-dependent in cHL.

In situ multiplex immunofluorescence analysis of the inflammatory burden in kidney allograft rejection: A new tool to characterize the alloimmune response

The exact composition of leukocyte infiltration during kidney allograft rejection is difficult to comprehend and visualize on the same biopsy slide. Using an innovative technology of multiplex immunofluorescence (mIF), we were able to detect simultaneously NK cells, macrophages, and T cells and to determine their intra- or extravascular localization using an endothelial marker. Twenty antibody-mediated rejection (ABMR), 20 T cell-mediated rejection (TCMR), and five normal biopsies were labeled, with automatic leukocyte quantification and localization. This method was compared to a classic NKp46 immunohistochemistry (IHC) with manual quantification and to mRNA quantification. mIF automatic quantification was strongly correlated to IHC (r = .91, P < .001) and to mRNA expression levels (r > .46, P < .021). T cells and macrophages were the 2 predominant populations involved in rejection (48.0 ± 4.4% and 49.3 ± 4.4%, respectively, in ABMR; 51.8 ± 6.0% and 45.3 ± 5.8% in TCMR). NK cells constituted a rare population in both ABMR (2.7 ± 0.7%) and TCMR (2.9 ± 0.6%). The intravascular compartment was mainly composed of T cells, including during ABMR, in peritubular and glomerular capillaries. However, NK cell and macrophage densities were significantly higher during ABMR in glomerular and peritubular capillaries. To conclude, this study demonstrates the feasibility and utility of mIF imaging to study and better understand the kidney allograft rejection process.

Mass cytometry defines distinct immune profile in germinal center B-cell lymphomas

Tumor-associated macrophage and T-cell subsets are implicated in the pathogenesis of diffuse large B-cell lymphoma, follicular lymphoma, and classical Hodgkin lymphoma. Macrophages provide essential mechanisms of tumor immune evasion through checkpoint ligand expression and secretion of suppressive cytokines. However, normal and tumor-associated macrophage phenotypes are less well characterized than those of tumor-infiltrating T-cell subsets, and it would be especially valuable to know whether the polarization state of macrophages differs across lymphoma tumor microenvironments. Here, an established mass cytometry panel designed to characterize myeloid-derived suppressor cells and known macrophage maturation and polarization states was applied to characterize B-lymphoma tumors and non-malignant human tissue. High-dimensional single-cell analyses were performed using dimensionality reduction and clustering tools. Phenotypically distinct intra-tumor macrophage subsets were identified based on abnormal marker expression profiles that were associated with lymphoma tumor types. While it had been proposed that measurement of CD163 and CD68 might be sufficient to reveal macrophage subsets in tumors, results here indicated that S100A9, CCR2, CD36, Slan, and CD32 should also be measured to effectively characterize lymphoma-specific tumor macrophages. Additionally, the presence of phenotypically distinct, abnormal macrophage populations was closely linked to the phenotype of intra-tumor T-cell populations, including PD-1 expressing T cells. These results further support the close links between macrophage polarization and T-cell functional state, as well as the rationale for targeting tumor-associated macrophages in cancer immunotherapies.

The role of CD68+ macrophage in classical Hodgkin lymphoma patients from Egypt

BACKGROUND

CD68+ tumor-associated macrophages (TAM) play an important role in the progression of classical Hodgkin lymphoma (cHL). We assessed the role of CD20 and CD68 + TAM in a cohort of cHL patients from Egypt and correlated the number of CD68 + cells with patients' characteristics, response to treatment, overall and progression free survival rates (OS & PFS).

METHODS

CD20 expression and CD68 + TAM numbers were assessed in representative tumor tissues obtained from 81 cHL patients using flowcytometry (FCM), immunohistochemistry (IHC), and Rt-PCR techniques.

RESULTS

The expression levels of CD68 protein by IHC was high in 27 (33.3%), moderate in 15 (18.5%), low in 15 (18.5%), and negative in 24 (29.6%) patients (p = 0.13). CD68-mRNA expression was high in 43/81(53.1%), and low in 38(46.9%) patients (p = 0.6). The number of CD68 + TAM (by FCM) was low (< 20 cells) in 42/81 (51.9%), and high (≥20 cells) in 39/81 (48.1%) patients (p = 0.74). CD68 expression (by FCM, IHC& Rt-PCR) associated significantly with poor response to treatment, decreased CD20 expression, reduced OS and PFS rates (p < 0.001 for all). CD68 expression (by Rt-PCR only) associated significantly with advanced disease stage (p = 0.04). The age of the patients, high CD20 expression & high CD68+ macrophage number were independent prognostic factors for OS (p= 0.02, p = 0.008 & p = 0.009; respectively). However, the age of the patient, high CD20, and high CD68+ macrophage expression (by FCM&IHC) were independent prognostic factors for DFS (p. = 0.004, p. = 0.01, p. = 0.007 and p. = 0.01; respectively).

CONCLUSION

CD68 + TAM expression (by Rt-PCR, FCM and/or IHC) can identify patients with poor response to treatment and reduced survival rates (OS& PFS). Assessment of CD68 + positive macrophages by FCM is superior to other methods (Rt-PCR and IHC) as a prognostic factor for DFS and OS rates.

Identification of a novel monocytic phenotype in Classic Hodgkin Lymphoma tumor microenvironment

Classic Hodgkin lymphoma (CHL) characteristically shows few malignant cells in a microenvironment comprised of mixed inflammatory cells. Although CHL is associated with a high cure rate, recent studies have associated poor prognosis with absolute monocyte count in peripheral blood and increased monocyte/macrophages in involved lymph nodes. Thus, the role of monocytic infiltration and macrophage differentiation in the tumor microenvironment of CHL may be more relevant than absolute macrophage numbers to defining prognosis in CHL patients and potentially have therapeutic implications. Most studies identify tumor-associated macrophages (TAMs) using markers (e.g., CD68) expressed by macrophages and other mononuclear phagocytes, such as monocytes. In contrast, Class A Scavenger Receptor (SR-A/CD204) is expressed by tissue macrophages but not monocytic precursors. In this study, we examined SR-A expression in CHL (n = 43), and compared its expression with that of other macrophage markers. We confirmed a high prevalence of mononuclear cells that stained with CD68, CD163, and CD14 in CHL lymph nodes. However, SR-A protein expression determined by immunohistochemistry was limited to macrophages localized in sclerotic bands characteristic of nodular sclerosis CHL. In contrast, SR-A protein was readily detectable in lymph nodes with metastatic tumor, extra-nodal CHL, T cell/histiocyte-rich large B cell lymphoma, and resident macrophages in non-malignant tissues, including spleen, lymph node, liver and lung. The results of SR-A protein expression paralleled the expression of SR-A mRNA determined by quantitative RT-PCR. These data provide evidence that tumor-infiltrating monocyte/macrophages in CHL have a unique phenotype that likely depends on the microenvironment of nodal CHL.

Immune and Inflammatory Cells of the Tumor Microenvironment Represent Novel Therapeutic Targets in Classical Hodgkin Lymphoma

Classical Hodgkin Lymphoma (cHL) is a B-cell malignancy that, typically, responds well to standard therapies. However, patients who relapse after standard regimens or are refractory to induction therapy have a dismal outcome. The implementation of novel therapies such as the anti-CD30 monoclonal antibody Brentuximab Vedotin and immune checkpoint inhibitors has provided curative options for many of these patients. Nonetheless, responses are rarely durable, emphasizing the need for new agents. cHL is characterized by a unique microenvironment in which cellular and humoral components interact to promote tumor survival and dissemination. Knowledge of the complex composition of cHL microenvironment is constantly evolving; in particular, there is growing interest in certain cell subsets such as tumor-associated macrophages, myeloid-derived suppressor cells and neutrophils, all of which have a relevant role in the pathogenesis of the disease. The unique biology of the cHL microenvironment has provided opportunities to develop new drugs, many of which are currently being tested in preclinical and clinical settings. In this review, we will summarize novel insights in the crosstalk between tumor cells and non-malignant inflammatory cells. In addition, we will discuss the relevance of tumor-microenvironment interactions as potential therapeutic targets.

CD163 is a predictive biomarker for prognosis of classical Hodgkin's lymphoma in Saudi patients

Hodgkin's lymphoma (HL) is a hematological malignancy characterized by a minority of neoplastic cells outnumbered by tumor-associated macrophages (TAMs). The overexpression of the CD163 antigen by TAMs is considered to be a significant predictive biomarker for risk stratification. This is likely caused by a genetic single-nucleotide polymorphism (SNP) at the gene promoter. The aim of the present retrospective case-control study was to establish a gene expression profile of a specific biomarker for classical HL (CHL) in order to predict the outcome and survival of CHL patients in Saudi Arabia. The protein expression of CD163 on TAMs was studied using immunohistochemistry (IHC). A prognosis index was calculated for the CD163 protein to assess the risk stratification of CHL. Genotyping of selected SNPs of this antigen was performed for 100 CHL cases and controls. The analysis revealed that the CD163 protein expression level was significantly correlated with disease relapse (DR) and overall survival (OS). In addition, the CD163 index threshold (15.0) was found to be significantly correlated with the relapse rate. Among the studied CD163 SNPs, rs75608120 exhibited a significant correlation with the DR rate of CHL patients, but not with OS. The findings of the present study confirmed that CD163 is a specific marker for TAMs, and its overexpression by TAMs is significantly associated with relapse and reduced survival post-therapy. In addition, a new methodology of indexing CD163 protein expression for HL risk stratification was proposed. Thus, the present study identified a specific predictive molecular and antigenic biomarker for CHL prognosis.

Interleukin 10 (IL10) proximal promoter polymorphisms beyond clinical response in classical Hodgkin lymphoma: Exploring the basis for the genetic control of the tumor microenvironment

Interleukin-10 (IL10) is an immune regulatory cytokine. Single nucleotide polymorphisms (SNPs) in IL10 promoter have been associated with prognosis in adult classical Hodgkin lymphoma (cHL). We analyzed IL10 SNPs -1082 and -592 in respect of therapy response, gene expression and tumor microenvironment (TME) composition in 98 pediatric patients with cHL. As confirmatory results, we found that -1082AA/AG; -592CC genotypes and ATA haplotype were associated with unfavourable prognosis: Progression-free survival (PFS) was shorter in -1082AA+AG (72.2%) than in GG patients (100%) (P = 0.024), and in -592AA (50%) and AC (74.2%) vs. CC patients (87.0%) (P = 0.009). In multivariate analysis, the -592CC genotype and the ATA haplotype retained prognostic impact (HR: 0.41, 95% CI 0.2-0.86; P = 0.018, and HR: 3.06 95% CI 1.03-9.12; P = 0.044, respectively). Our analysis further led to some new observations, namely: (1) Low IL10 mRNA expression was associated with -1082GG genotype (P = 0.014); (2) IL10 promoter polymorphisms influence TME composition;-1082GG/-592CC carriers showed low numbers of infiltrating cells expressing MAF transcription factor (20 vs. 78 and 49 vs. 108 cells/mm², respectively; P< 0.05); while ATA haplotype (high expression) associated with high numbers of MAF+ cells (P = 0.005). Specifically, -1082GG patients exhibited low percentages of CD68+MAF+ (M2-like) intratumoral macrophages (15.04% vs. 47.26%, P = 0.017). Considering ours as an independent validation cohort, our results give support to the clinical importance of IL10 polymorphisms in the full spectrum of cHL, and advance the concept of genetic control of microenvironment composition as a basis for susceptibility and therapeutic response.

The heterogenic tumor microenvironment of hepatocellular carcinoma and prognostic analysis based on tumor neo-vessels, macrophages and α-SMA

The present study was performed to quantify tumor neo-vessels, macrophages and fibroblasts in the tumor microenvironment of hepatocellular carcinoma (HCC) and explore the prognostic factors of HCC. The distribution of tumor neo-vessels, macrophages and fibroblasts was quantified by immunohistochemistry and inverted microscopy with the CRi Nuance multispectral imaging system, and the correlation of these parameters with the clinico-pathological characteristics and overall survival of the patients was analyzed. The number of tumor neo-vessels and macrophages, and density of the fibroblasts, as calculated by the thickness of the tumor stroma in the tumor microenvironment, ranged from 51-429 (median, 218), 110-555 (median, 259) and 35.6-555.5 µm (median, 247.0), respectively. Using the median values as a cutoff, the cases were stratified into high- and low-density groups. Survival analysis demonstrated that the high-density groups regarding macrophages (χ²=5.249, P=0.022) and fibroblasts (χ²=18.073, P<0.001) had a significantly shorter disease-free survival (DFS) than the low-density groups. The high-density tumor neo-vessel group had a shorter DFS with a median of 5 months than the low-density group with a median of 7 months; however, there was no statistical significance between these two groups (χ²=1.663, P=0.197). Regarding the above three stromal components combined, all of the cases were classified into low-, middle- and high-density groups. Survival analysis demonstrated that the high-density group of stromal components had a shorter DFS than the other two groups with a median of 3 months (χ²=14.439, P=0.001). Multivariate analysis by Cox regression indicated that cirrhosis, metastasis stage, as well as macrophage and fibroblast density were independent prognostic factors. In conclusion, the key elements in the tumor microenvironment, including tumor neo-vessels, macrophages and fibroblasts, were heterogenic in HCC tissues and have significant roles in HCC invasion and metastasis. Stromal components are associated with the prognosis of patients with HCC; the higher the density of stromal components, the poorer the prognosis of patients with HCC.

SOHO State of the Art Updates and Next Questions: Hodgkin Lymphoma

Until recently, advances in classic Hodgkin lymphoma (HL) treatment primarily consisted of minor modifications of highly effective decades-old chemotherapy and radiation approaches. In early-stage disease, excellent outcomes have been reported with fewer cycles of chemotherapy, lower doses, smaller radiation fields and in some circumstances, radiation elimination. In advanced-stage disease, maintaining the dose intensity of standard chemotherapy regimens has resulted in modest improvements in outcomes. During the past decade, the use of early interim positron emission tomography (PET) scans to escalate or de-escalate treatment has been the subject of intense investigation with the goal of maximizing efficacy and minimizing toxicity. Important updates from recent PET-directed trials include; elimination of bleomycin in patients with advanced-stage HL and negative interim PET findings, the benefit of therapy escalation in patients with unfavorable early-stage HL and positive interim PET findings, and the minimal benefit of consolidative radiotherapy in patients with unfavorable early-stage HL and negative interim PET findings. A more nuanced approach to consolidative radiotherapy is required for patients with favorable early-stage disease based on age, disease sites, secondary cancer risk, and cardiovascular disease. Brentuximab vedotin and nivolumab/pembrolizumab have provided promising new options with surprisingly high response rates and modest toxicity for patients with relapsed HL whose disease does not respond to standard treatments. Incorporating these agents into earlier therapy is an area of active investigation for all stages of HL. Although the overall prognosis for HL patients has seen incremental improvement, efforts to optimize treatment with more effective and less toxic approaches continue.

Clinicopathological correlation of tumor-associated macrophages in Ewing sarcoma

AIMS

Tumor-associated macrophages (TAMs) are known markers playing complex roles in tumorigenesis. However, the function of TAMs in a variety of malignancies is not yet fully understood. The aim of this pilot study was to quantify the density of TAMs in Ewing sarcoma and to determine the correlation between TAMs and clinicopathological parameters.

METHODS

Using immunohistochemistry, the expressions of CD68 and CD163 were examined in 24 tissue samples of Ewing sarcoma of bone. The density of CD68 and CD163-positive TAMs was analyzed quantitatively and semi-quantitatively and statistically correlated with clinical parameters.

RESULTS

CD163-positive TAMs outnumbered CD68-positive cells (median of 130 vs 96, respectively). No statistically significant relatio nship was found between density of CD68-positive cells, clinical parameters or prognosis. However, high levels of CD163-positive TAMs were associated with localized disease (P=0.008). In cases with a higher density of CD163-positive cells, a trend toward longer survival was revealed (P=0.063).

CONCLUSION

This is the first study that has quantified CD163 expression in TAMs in Ewing sarcoma and showed its possible prognostic value. CD163 was confirmed to be a more specific marker of macrophages than CD68. CD163 is not an exclusive hallmark of M2 macrophages.

An anergic immune signature in the tumor microenvironment of classical Hodgkin lymphoma is associated with inferior outcome

OBJECTIVE

The classical Hodgkin lymphoma (cHL) tumor microenvironment shows an ongoing inflammatory response consisting of varying degrees of infiltrating eosinophils, mast cells, macrophages, regulatory T lymphocytes (Tregs), and activated lymphocytes surrounding the malignant cells. Herein, different immune signatures are characterized and correlated with treatment outcome.

METHODS

Tumor-infiltrating leukocytes were phenotyped in biopsies from 459 patients with cHL. Time to progression (TTP) (primary progression, relapse, or death from cHL) and overall survival were analyzed using Cox proportional hazards regression.

RESULTS

The leukocyte infiltration in the microenvironment was highly diverse between patients and was categorized in 4 immune signatures (active, anergic, innate, or mixed). A high proportion of Tregs (anergic) resulted in shorter TTP (median 12.9-year follow-up) in age-adjusted analyses (hazard ratio = 1.82; 95% confidence interval 1.05-3-15). Epstein-Barr virus (EBV)-positive cases had higher proportions of macrophages and activated lymphocytes than EBV negative, but neither of those leukocytes predicted prognosis.

CONCLUSIONS

Abundant Tregs (anergic signature) indicate a shorter TTP, particularly in younger patients. This is probably due to a reduced ability of the immune system to attack the tumor cells. Our data warrant further investigation if these suggested immune signatures could predict outcome of immunotherapy such as immune checkpoint inhibitors.

High proportions of PD-1+ and PD-L1+ leukocytes in classical Hodgkin lymphoma microenvironment are associated with inferior outcome

Immune checkpoint inhibition targeting the programmed death receptor (PD)-1 pathway is a novel treatment approach in relapsed and refractory classical Hodgkin lymphoma (cHL). Identifying patients with a high risk of treatment failure could support the use of PD-1 inhibitors as front-line treatment. Our aim was to investigate the prognostic impact of PD-1, programmed death-ligand 1 (PD-L1), and PD-L2 in the tumor microenvironment in diagnostic biopsies of patients with cHL. Patients from Denmark and Sweden, diagnosed between 1990 and 2007 and ages 15 to 86 years, were included. Tissue microarray samples were available from 387 patients. Immunohistochemistry was used to detect PD-1, PD-L1, and PD-L2, and the proportions of positive cells were calculated. Event-free survival (EFS; time to treatment failure) and overall survival (OS) were analyzed using Cox proportional hazards regression. High proportions of both PD-1⁺ (hazard ratio [HR], 1.77; 95% confidence interval [CI], 1.10-2.86) and PD-L1⁺ (HR = 1.89; 95% CI, 1.08-3.30) leukocytes in the microenvironment were associated with inferior EFS in a multivariate analysis (adjusted for white blood cell count >15 × 10⁹/L, hemoglobin <105 g/L, albumin <40 g/L, B symptoms, extranodal involvement, stage, bulky tumor, nodular sclerosis subtype, Epstein-Barr virus status, lymphocyte count <0.6 × 10⁹/L, sex, and country). A high proportion of PD-L1⁺ leukocytes was also associated with inferior OS in a multivariate analysis (HR, 3.46; 95% CI, 1.15-10.37). This is the first study to show a correlation after multivariate analysis between inferior outcome in cHL and a high proportion of both PD-1⁺ and PD-L1⁺ leukocytes in the tumor microenvironment.

Regulatory myeloid cells: an underexplored continent in B-cell lymphomas

In lymphomas arising from the germinal center, prognostic factors are linked to the myeloid compartment. In particular, high circulating monocyte or myeloid-derived suppressor cell counts are associated with poor prognosis for patients with high-grade B-cell lymphomas. Macrophages with an M2 phenotype are enriched within lymphoma tumors. However, the M1/M2 nomenclature is now deprecated and the clinical impact of this phenotype remains controversial. Across cancer types, myeloid cells are primarily thought to function as immune suppressors during tumor initiation and maintenance, but the biological mechanisms behind the myeloid signatures are still poorly understood in germinal center B-cell lymphomas. Herein, we describe the role and clinical relevance of myeloid cells in B-cell lymphoma and propose innovative approaches to decipher this complex cellular compartment. Indeed, characterization of this heterogeneous cell ecosystem has been largely accomplished with "low-resolution" approaches like morphological evaluation and immunohistochemistry, where cells are characterized using a few proteins and qualitative metrics. High-resolution, quantitative approaches, such as mass cytometry, are valuable to better understand myeloid cell diversity, functions, and to identify potential targets for novel therapies.

The Pathobiology and Treatment of Hodgkin Lymphoma. Where do We go from Gianni Bonadonna's Lesson?

This article reviews the evolution of the diagnosis and treatment of Hodgkin lymphoma (HL) since its discovery in 1832. The morphological, phenotypic and molecular characteristics of both nodular lymphocyte-predominant HL and classical HL are revised in the light of recent molecular information and possible impact on the identification of risk groups as well as the use of targeted therapies. The seminal contribution of Gianni Bonadonna to developing new treatment strategies for both advanced and early-stage HL is highlighted.

CD68/macrosialin: not just a histochemical marker

CD68 is a heavily glycosylated glycoprotein that is highly expressed in macrophages and other mononuclear phagocytes. Traditionally, CD68 is exploited as a valuable cytochemical marker to immunostain monocyte/macrophages in the histochemical analysis of inflamed tissues, tumor tissues, and other immunohistopathological applications. CD68 alone or in combination with other cell markers of tumor-associated macrophages showed a good predictive value as a prognostic marker of survival in cancer patients. Lowression of CD68 was found in the lymphoid cells, non-hematopoietic cells (fibroblasts, endothelial cells, etc), and tumor cells. Cell-specific CD68 expression and differentiated expression levels are determined by the complex interplay between transcription factors, regulatory transcriptional elements, and epigenetic factors. Human CD68 and its mouse ortholog macrosialin belong to the family of LAMP proteins located in the lysosomal membrane and share many structural similarities such as the presence of the LAMP-like domain. Except for a second LAMP-like domain present in LAMPs, CD68/microsialin has a highly glycosylated mucin-like domain involved in ligand binding. CD68 has been shown to bind oxLDL, phosphatidylserine, apoptotic cells and serve as a receptor for malaria sporozoite in liver infection. CD68 is mainly located in the endosomal/lysosomal compartment but can rapidly shuttle to the cell surface. However, the role of CD68 as a scavenger receptor remains to be confirmed. It seems that CD68 is not involved in binding bacterial/viral pathogens, innate, inflammatory or humoral immune responses, although it may potentially be involved in antigen processing/presentation. CD68 could be functionally important in osteoclasts since its deletion leads to reduced bone resorption capacity. The role of CD68 in atherosclerosis is contradictory.

Meta-analysis of the prognostic and clinical value of tumor-associated macrophages in adult classical Hodgkin lymphoma

BACKGROUND

The prognostic significance of tumor-associated macrophages (TAM) in adult classical Hodgkin lymphoma (cHL) remains controversial. Here, we report a meta-analysis of the association of CD68 and CD163 infiltration on the clinical outcome of adult cHL.

METHODS

A comprehensive search to identify relevant articles was performed in PubMed, Embase, and Google Scholar on January 31, 2016. Using the fixed effect or random effects model of DerSimonian and Laird, hazard ratios (HR) or odds ratios (OR) with 95 % confidence intervals (CIs) were used as the effect size estimate.

RESULTS

Twenty-two eligible studies with a total of 2959 patients were identified. Our analysis indicated that a high density of CD68⁺ TAMs in the tumor microenvironment of adult cHL predicted poor overall survival (OS) (HR: 2.41; 95 % CI, 1.92-3.03), shorter progression-free survival (PFS) (HR: 1.78; 95 % CI, 1.45-2.18), and poor disease-specific survival (HR: 2.71; 95 % CI, 1.38-5.29). High density of CD163⁺ TAMs in the tumor microenvironment of adult cHL also predicted poor OS (HR: 2.75; 95 % CI, 1.58-4.78) and poor PFS (HR: 1.66; 95 % CI, 1.22-2.27). In addition, we demonstrated that a high density of either CD68⁺ or CD163⁺ TAMs was associated with the presence of Epstein-Barr virus in neoplastic cells (OR_CD68: 3.13; 95 % CI, 2.02-4.84; OR_CD163: 2.88; 95 % CI, 1.55-5.34). A high density of either CD68⁺ or CD163⁺ TAMs tend to be associated with a more advanced clinical stage (OR_CD68: 1.25; 95 % CI, 0.93-1.67; OR _CD163: 1.19; 95 % CI, 0.86-1.63), B-symptoms (OR_CD68: 1.35; 95 % CI, 0.90-2.01; OR_CD163: 2.19; 95 % CI, 0.96-5.03), higher International Prognostic Factors Project Score (OR_CD68: 1.20; 95 % CI, 0.67-2.15; OR_CD163: 2.00; 95 % CI, 0.92-4.35), and bulky disease (OR_CD68: 1.47; 95 % CI, 0.88-2.47; OR_CD163: 1.19; 95 % CI, 0.72-1.96).

CONCLUSIONS

Our analyses suggest that a high density of either CD68⁺ or CD163⁺ TAMs is a robust predictor of adverse outcomes in adult cHL. Increased TAMs should be taken into account to further improve prognostic stratification and the planning of appropriate therapeutic strategies.

The Lymphocyte-Monocyte Ratio and the Platelet-Lymphocyte Ratio at Diagnosis as Independent Prognostic Factors in Primary Gastrointestinal Diffuse Large B Cell Lymphoma

To study the role of the absolute lymphocyte count (ALC), absolute monocyte count (AMC), platelet count (PLT), lymphocyte-monocyte ratio (LMR) and the platelet-lymphocyte ratio (PLR) in the prognosis of primary gastrointestinal diffuse large B cell lymphoma (PGI-DLBCL). We retrospectively analyzed the prognostic value of the ALC, AMC, PLT, LMR, PLR at diagnosis in 173 PGI-DLBCL patients through histopathological examination from March 2009 to February 2015. In total, 173 patients with histopathological diagnosis of PGI-DLBCL in this study, the median age was 51 years (range 12-90 years), median follow-up time was 44 months (range 7-89 months). In univariate analysis, age <60 years, B symptoms, Lugano stage I-II, low international prognostic index (IPI) or low age-adjusted international prognostic index (aaIPI), normal lactate dehydrogenase (LDH), normal β2-microglobulin (β2m), Hb ≥ 11 g/dL, ALC ≥ 1.5 × 10⁹/L, AMC ≤ 0.50 × 10⁹/L, LMR ≥ 2.5, PLR ≤ 170 were related with superior overall survival (OS) and progression-free survival (PFS) (p ≤ 0.05). Multivariate analysis suggested that ALC, LMR, LDH were related with PFS (p ≤ 0.05). Similarly, age and LMR were related with OS (p ≤ 0.05). The parameters (ALC, AMC, LMR, PLR) may be valuable prognostic factors in PGI-DLBCL patients. LMR, PLR at diagnosis are expected to be independent prognostic factors for PGI-DLBCL patients.

Splenic Marginal Zone Granulocytes Acquire an Accentuated Neutrophil B-Cell Helper Phenotype in Chronic Lymphocytic Leukemia

Recruitment of tumor-associated macrophages and neutrophils (TAM and TAN) to solid tumors contributes to immunosuppression in the tumor microenvironment; however, their contributions to lymphoid neoplasms are less clear. In human chronic lymphocytic leukemia (CLL), tumor B cells lodge in lymph nodes where interactions with the microenvironment occur. Tumor cell homing stimulates proliferation, such that engagement of the B-cell receptor is important for malignant progression. In the Eμ-Tcl1 murine model of CLL, we identified gene expression signatures indicative of a skewed polarization in the phenotype of monocytes and neutrophils. Selective ablation of either of these cell populations in mice delayed leukemia growth. Despite tumor infiltration of these immune cells, a systemic inflammation was not detected. Notably, in progressive CLL, splenic neutrophils were observed to differentiate toward a B-cell helper phenotype, a process promoted by the induction of leukemia-associated IL10 and TGFβ. Our results suggest that targeting aberrant neutrophil differentiation and restoring myeloid cell homeostasis could limit the formation of survival niches for CLL cells. Cancer Res; 76(18); 5253-65. ©2016 AACR.

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.

Logic Learning Machine and standard supervised methods for Hodgkin's lymphoma prognosis using gene expression data and clinical variables

This study evaluates the performance of a set of machine learning techniques in predicting the prognosis of Hodgkin's lymphoma using clinical factors and gene expression data. Analysed samples from 130 Hodgkin's lymphoma patients included a small set of clinical variables and more than 54,000 gene features. Machine learning classifiers included three black-box algorithms ( k-nearest neighbour, Artificial Neural Network, and Support Vector Machine) and two methods based on intelligible rules (Decision Tree and the innovative Logic Learning Machine method). Support Vector Machine clearly outperformed any of the other methods. Among the two rule-based algorithms, Logic Learning Machine performed better and identified a set of simple intelligible rules based on a combination of clinical variables and gene expressions. Decision Tree identified a non-coding gene ( XIST) involved in the early phases of X chromosome inactivation that was overexpressed in females and in non-relapsed patients. XIST expression might be responsible for the better prognosis of female Hodgkin's lymphoma patients.

Independent prognostic impact of tumour-infiltrating macrophages in early-stage Hodgkin's lymphoma

Although patients with early-stage Hodgkin's lymphoma have a high rate of cure, a portion of these are resistant to or relapse after standard treatment. Current prognostic criteria based on clinical and laboratory parameters at diagnosis do not allow to accurately identify the subset of patients with less favourable clinical outcome. An increased number of tumour-infiltrating macrophages was found to be associated with shortened survival in patients with classic Hodgkin's Lymphoma. The aim of this study was to assess the clinical significance of the proportion of CD68-positive infiltrating macrophages in patients with early-stage classic Hodgkin's lymphoma. By using immunohistochemistry technique, we evaluated for CD68 expression diagnostic biopsies of 106 patients affected by supradiaphragmatic early-stage classic Hodgkin's lymphoma treated at our institution since 2000 to 2010. All patients were treated with adriamycin, bleomycin, vinblastine, and dacarbazine chemotherapy followed by radiotherapy in the majority. The 2-year overall survival and progression-free survival (PFS) in the entire cohort were 97% and 83% respectively. The 2-year PFS was statistically different between patients with favourable and those with unfavourable prognosis according to the European Organisation for Research and Treatment of Cancer (EORTC) risk criteria (96% vs 79%, p = 0.039) and between patients having less than 25% of CD68-positive infiltrating macrophages and those with more than 25% (85% vs 67%, p = 0.012). All patients with favourable EORTC criteria had CD68 expression lower than 25%. Within those with unfavourable EORTC criteria, patients with a CD68+ count greater than 25% had a worse 2-year PFS than patients having values lower than 25% (64% vs 82%, p = 0.03). Moreover, in multivariate analysis, after adjusting for CD68+ macrophages count and EORTC score, only CD68+ macrophages count higher than 25% retained a prognostic effect on PFS (hazard ratio = 2.8, 95%CI: 1.1-7.6, p = 0.038). Our data show that a proportion of tumour-infiltrating macrophages greater than 25% is associated with unfavourable clinical outcome in patients with early-stage Hodgkin's lymphoma Copyright © 2016 John Wiley & Sons, Ltd.

CD68+ cell count, early evaluation with PET and plasma TARC levels predict response in Hodgkin lymphoma

Early response evaluation with [¹⁸F]fluordeoxyglucose (FDG) positron emission tomography after 2 cycles of chemotherapy (interim PET) has been indicated as the strongest predictor for outcome in classical Hodgkin lymphoma (HL). We studied the prognostic role of the number of tumor‐infiltrating CD68+ cells and of the plasma levels of TARC (thymus and activation‐regulated chemokine) in the context of interim PET in 102 patients with classical HL treated with Adriamycin, Bleomycin, Vinblastine, Dacarbazine (ABVD). After 2 ABVD cycles, interim PET according to Deauville criteria was negative (score 0–3) in 85 patients and positive (score 4–5) in 15 patients (2 patients technically not evaluable). TARC levels were elevated in 89% of patients at diagnosis, and decreased after 2 cycles in 82% of patients. Persistently elevated TARC levels in 18% of patients were significantly associated with a positive PET result (P = 0.007). Strong predictors for progression‐free survival (PFS) were a negative interim PET (85% vs. 28%, P < 0.0001) and CD68+ cell counts <5% (89% vs. 67%, P = 0.006), while TARC levels at diagnosis and at interim evaluation had no prognostic role. In multivariate analysis, interim PET, CD68+ cell counts and presence of B‐symptoms were independently associated with PFS. We conclude that although TARC levels are a biomarker for early response evaluation, they cannot substitute for interim PET as outcome predictor in HL. The evaluation of CD68 counts and B‐symptoms at diagnosis may help to identify low‐risk patients regardless positive interim PET.

Evaluation of the prognostic role of tumour-associated macrophages in newly diagnosed classical Hodgkin lymphoma and correlation with early FDG-PET assessment

In Hodgkin Lymphoma (HL), about 20% of patients still have relapsed/refractory disease and late toxic effects rate continue to rise with time. 'Early FDG-PET' and tissue macrophage infiltration (TAM) emerged as powerful prognostic predictors. The primary endpoint was to investigate the prognostic role of both early FDG-PET and TAM; the secondary endpoint was to test if early FDG-PET positivity could correlate with high TAM score. A cohort of 200 HL patients was analysed. Induction treatment plan consisted of two to six courses of ABVD and, if indicated, involved field radiation therapy. All patients repeated CT scan and FDG-PET after two cycles and after the completion of therapy. TAM in diagnostic specimens was determined by immunohistochemistry with a monoclonal antibody (anti-CD68 KP1). Overall, early FDG-PET was negative in 163 patients (81.5%) and positive in 37 patients (18.5%), showing a significant correlation with the achievement of CR (p < 0.0001). After a median follow-up of 40 months, progression free survival (PFS) was significantly better for PET negative patients (p < 0.0001). CD68 expression was low, intermediate or high in 26 (13%), 100 (50%) and 74 (37%) cases, without difference in the distribution between responders and non-responders. PFS analysis showed no significant difference in any score group. TAM score did not show any correlation with early FDG-PET result. This study confirms that early FDG-PET has a high prognostic power, while TAM score does not seem to influence the outcome; in contrast to our original hypothesis, it does not correlate with FDG-PET assessment. Copyright © 2015 John Wiley & Sons, Ltd.

Microenvironment-related biomarkers and novel targets in classical Hodgkin's lymphoma

Classical Hodgkin's lymphoma accounts for approximately 10% of all malignant lymphomas. Although most patients can be cured with modern treatment strategies, approximately 25% of them experience either primary or secondary chemorefractoriness or disease relapse, thus requiring novel treatments. Increasing preclinical and clinical evidences have demonstrated the role of microenvironment in the molecular pathogenesis of classical Hodgkin's lymphoma and elucidated the complex cross-talk between the malignant Hodgkin Reed–Sternberg cells and the nonmalignant, reactive cells of the microenvironment, strongly supporting novel therapeutic approaches aimed at targeting Hodgkin's Reed–Sternberg cells along with reactive cells in order to overcome chemorefractoriness. In the near future, these novel therapies will also be tested in chemosensitive patients to reduce long-term toxicities of chemo-radiotherapy.

CSF1R Protein Expression in Reactive Lymphoid Tissues and Lymphoma: Its Relevance in Classical Hodgkin Lymphoma

Tumour-associated macrophages (TAMs) have been associated with survival in classic Hodgkin lymphoma (cHL) and other lymphoma types. The maturation and differentiation of tissue macrophages depends upon interactions between colony-stimulating factor 1 receptor (CSF1R) and its ligands. There remains, however, a lack of consistent information on CSF1R expression in TAMs. A new monoclonal antibody, FER216, was generated to investigate CSF1R protein distribution in formalin fixed tissue samples from 24 reactive lymphoid tissues and 187 different lymphoma types. We also analysed the distribution of CSF1R+, CD68+ and CD163+ macrophages by double immunostaining, and studied the relationship between CSF1R expression and survival in an independent series of 249 cHL patients. CSF1R+ TAMs were less frequent in B-cell lymphocytic leukaemia and lymphoblastic B-cell lymphoma than in diffuse large B-cell lymphoma, peripheral T-cell lymphoma, angioimmunoblastic T-cell lymphoma and cHL. HRS cells in cHL and, with the exception of three cases of anaplastic large cell lymphoma, the neoplastic cells in NHLs, lacked detectable CSF1R protein. A CSF1R+ enriched microenvironment in cHL was associated with shorter survival in an independent series of 249 cHL patients. CSF1R pathway activation was evident in the cHL and inactivation of this pathway could be a potential therapeutic target in cHL cases.

Clinical Impact of the Immunome in Lymphoid Malignancies: The Role of Myeloid-Derived Suppressor Cells

The better definition of the mutual sustainment between neoplastic cells and immune system has been translated from the bench to the bedside acquiring value as prognostic factor. Additionally, it represents a promising tool for improving therapeutic strategies. In this context, myeloid-derived suppressor cells (MDSCs) have gained a central role in tumor developing with consequent therapeutic implications. In this review, we will focus on the biological and clinical impact of the study of MDSCs in the settings of lymphoid malignancies.

Pediatric Hodgkin lymphoma in a South Indian regional cancer center: its immunomorphology, tumor-associated macrophages, and association with Epstein-Barr virus

Pediatric Hodgkin lymphoma (HL) comprises approximately a fifth of all patients with HL in India. Seventy-four cases of pediatric classical Hodgkin Lymphoma (cHL) from a regional cancer center in southern India were analyzed on a tissue microarray (TMA) for the stage of B-cell differentiation of the Hodgkin/Reed Sternberg (HRS) cell by immunohistochemistry (IHC) using CD10, bcl6, MUM1/IRF4, and CD 138. Fifty-two of seventy-four (70.3%) cases were of late germinal center/early post-germinal center phenotype (CD10-/bcl6-/MUM1+/CD138-). Epstein-Barr virus (EBV) association using Epstein-Barr virus encoded RNA (EBER) RISH and EBV-LMP1 immunohistochemistry (IHC) revealed an EBV association of 93%. Tumor-associated macrophages (TAM) in the microenvironment were also assessed on the TMA by CD68 IHC, and most cases (59.7%) showed >25% TAMs, with no case showing ≤5%. These findings indicate that pediatric cHL in India is a tumor, predominantly, of late germinal center/early post-germinal center B cells, is almost invariably EBV associated, and with a high number of TAMs in the microenvironment. This latter finding suggests that criteria other than TAM scores need to be developed for risk stratification of pediatric EBV-associated HL especially in developing countries.