Immune Microenvironment Features and Dynamics in Hodgkin Lymphoma

Simple Summary

As happens in all neoplasms, the many reciprocal interactions taking place between neoplastic cells and the other reactive cells impact the course of the disease. Hodgkin Lymphoma is an haematologic malignancy where most of the pathological tissue is indeed composed by reactive cells and few neoplastic cells. Consequently, it represents an interesting subject for the description of the neoplastic and non-neoplastic cells interaction. In this review we report and discuss the more recent findings of microenvironmental studies about this disease.

Abstract

Classical Hodgkin’s lymphoma (cHL) accounts for 10% of all lymphoma diagnosis. The peculiar feature of the disease is the presence of large multinucleated Reed–Sternberg and mononuclear Hodgkin cells interspersed with a reactive microenvironment (ME). Due to the production of a large number of cytokines, Hodgkin cells (HCs) and Hodgkin Reed–Sternberg cells (HRSCs) attract and favour the expansion of different immune cell populations, modifying their functional status in order to receive prosurvival stimuli and to turn off the antitumour immune response. To this purpose HRSCs shape a biological niche by organizing the spatial distribution of cells in the ME. This review will highlight the contribution of the ME in the pathogenesis and prognosis of cHL and its role as a possible therapeutic target.

Prognostic value of Bcl2 and p53 in Hodgkin lymphoma: A systematic review and meta-analysis

AIMS

Several studies suggested that high expression of Bcl2 and/or p53 in Hodgkin/Reed-Sternberg cells is an unfavorable prognostic factor in Hodgkin lymphoma (HL). However, results in this field appear contrasting. We aimed to assess the prognostic value of p53 and Bcl2 in HL through a systematic review and meta-analysis.

METHODS

Electronic databases were searched from January 2000 to December 2020 for all studies assessing the prognostic value of p53 and Bcl2 in HL. The association of high p53 or Bcl2 expression with overall survival (OS), progression-free survival (PFS) and response to treatment was assessed by using hazard ratio (HR) and odds ratio (OR).

RESULTS

Eighteen studies were included. Bcl2 overexpression was significantly associated with decreased PFS (HR = 2.202; p < 0.0001), while the associations with decreased OS (HR = 1.565; p = 0.257) and refractoriness to treatment (OR = 0.482; p = 0.068) were non-significant. p53 overexpression was not significantly associated with refractoriness to treatment (OR = 0.904; p = 0.155); the analysis of OS and PFS was not feasible, but published data suggested the absence of a significant association.

CONCLUSIONS

In HL, Bcl2 overexpression is associated with decreased PFS, while a significant prognostic value could not be demonstrated for p53. Defining optimal criteria for interpreting Bcl2 and p53 immunostaining is necessary to draw definitive conclusions.

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.

Prognostic value of lymphocyte/monocyte ratio in advanced Hodgkin lymphoma: correlation with International Prognostic Score and tumor associated macrophages

We studied the prognostic significance of the absolute lymphocyte/monocyte count ratio (ALC/AMC), its contribution to the prognostic value of the International Prognostic Score (IPS), and evaluated if ALC/AMC could serve as a proxy for the frequency of CD68 + tumor-associated macrophages (TAMs) in 101 patients with advanced Hodgkin lymphoma (HL). The receiver operating characteristic (ROC) curve identified best cut-off values of 2.0 for ALC/AMC and 25% for CD68 + TAM. Patients with ALC/AMC < 2, IPS > 2 and > 25% CD68 + TAM had an inferior overall survival (OS) and event-free survival (EFS). Spearman's test also uncovered a significant correlation between the ALC/AMC and TAM. Multivariate analysis identified ALC/AMC < 2, IPS > 2 and > 25% CD68 + TAM as poor prognostic factors of OS and EFS. After evaluating ALC/AMC and IPS, we stratified patients into three progressively-worse-outcome groups (low-risk: 0 risk factors; intermediate: 1 risk factor; high: 2 risk factors). Our study encourages the combination of ALC/AMC with IPS, for refining risk prediction in advanced HL patients.

The classical Hodgkin lymphoma tumor microenvironment: macrophages and gene expression-based modeling

Despite the high cure rate in classical Hodgkin lymphoma (CHL), more accurate tailoring of upfront treatment is required to maximize cure while avoiding unnecessary short- and long-term treatment side effects. To this end, the unique tumor microenvironment of CHL has been searched extensively for prognostic biomarkers. Beyond targeted immunohistochemistry (IHC) studies, gene expression profiling (GEP) of diagnostic whole tissue biopsies has allowed a de novo approach to biomarker discovery. Among numerous candidate biomarkers, an association between the number of tumor-associated macrophages in the microenvironment and outcomes after ABVD (doxorubicin + bleomycin + vinblastine + dacarbazine) chemotherapy emerged, and multiple subsequent studies have validated this biological relationship using IHC. These studies have also defined key aspects for macrophage interrogation, including the characteristics of the CD68 and CD163 antibodies, appropriate scoring methodologies, and the identification of specific patient populations in which macrophage IHC may not be prognostic. The GEP studies also led to the development of gene expression-based prognostic models for advanced-stage CHL, with new technologies allowing reliable gene expression quantitation using RNA from routinely produced formalin-fixed paraffin-embedded biopsies. The bridge to predictive biomarkers that can be used reliably to inform upfront treatment selection requires further studies to demonstrate that these biomarkers can identify robustly, at diagnosis, patients at high risk of treatment failure with ABVD and that this risk may be overcome using alternative treatments.

LGALS3 as a prognostic factor for classical Hodgkin's lymphoma

LGALS3, a member of the lectin family, has an important role in tumor progression through inhibition of apoptosis. LGALS3 shares several significant structural properties with BCL2. In this study, we examined the prognostic significance of LGALS3 and BCL2 in uniformly treated classical Hodgkin's lymphoma. Diagnostic tissues from 110 patients with uniformly treated classical Hodgkin's lymphoma were evaluated retrospectively by immunohistochemical analysis of LGALS3 and BCL2 expression. The median follow-up time was 6.2 years (range, 0.2-17.3 years). Twenty-seven patients (25%) expressed LGALS3 protein in Hodgkin/Reed-Sternberg cells, which was associated with poor overall survival and event-free survival (P=0.007 and P<0.001). Fifteen patients (14%) expressed BCL2 protein in Hodgkin/Reed-Sternberg cells, which was not associated with overall survival and event-free survival (P=0.928 and P=0.900).There was no correlation between LGALS3 and BCL2 expression (P=0.193). Multivariate analysis identified LGALS3 protein as an independent prognostic factor for event-free survival (P=0.007). Subgroup analysis according to the Ann Arbor stage of classical Hodgkin's lymphoma showed that LGALS3 protein expression had a prognostic value in limited-stage classical Hodgkin's lymphoma (P<0.001). The results of this study suggest that LGALS3 is an independent prognostic factor in classical Hodgkin's lymphoma, and may allow the identification of a subgroup of patients with limited-stage classical Hodgkin's lymphoma who require more intensive therapy.

Oncogenic potential of Nrf2 and its principal target protein heme oxygenase-1

Nuclear factor erythroid 2-related factor 2 (Nrf2) is an essential component of cellular defense against a vast variety of endogenous and exogenous insults, including oxidative stress. Nrf2 acts as a master switch in the circuits upregulating the expression of various stress-response proteins, especially heme oxygenase-1 (HO-1). Paradoxically, however, recent studies have demonstrated oncogenic functions of Nrf2 and its major target protein HO-1. Levels of Nrf2 and HO-1 are elevated in many different types of human malignancies, which may facilitate the remodeling of the tumor microenvironment making it advantageous for the autonomic growth of cancer cells, metastasis, angiogenesis, and tolerance to chemotherapeutic agents and radiation and photodynamic therapy. In this context, the cellular stress response or cytoprotective signaling mediated via the Nrf2-HO-1 axis is hijacked by cancer cells for their growth advantage and survival of anticancer treatment. Therefore, Nrf2 and HO-1 may represent potential therapeutic targets in the management of cancer. This review highlights the roles of Nrf2 and HO-1 in proliferation of cancer cells, their tolerance/resistance to anticancer treatments, and metastasis or angiogenesis in tumor progression.

CD163 expression was associated with angiogenesis and shortened survival in patients with uniformly treated classical Hodgkin lymphoma

Background

Recent studies have reported the prognostic value of tissue-associated magrophages (TAMs) in classical Hodgkin lymphoma (cHL). In addition, TAMs are implicated in the tumor angiogenesis. In this study, we examined the prognostic relevance of TAMs in relation to vascular endothelial growth factor (VEGF) expression and angiogenesis in uniformly treated cases of cHL.

Methods

Diagnostic tissue from 116 patients with ABVD-treated cHL was evaluated retrospectively by immunohistochemical analysis for CD68, CD163 and VEGF expression and for CD31 expression as a measure of microvessel density (MVD).

Results

High CD163 expression (≥35% of cellularity) correlated with VEGF expression (Pearson’s Chi-square test, P = 0.008) and MVD (Spearman correlation coefficient 0.310, P<0.001). High CD163 expression was associated with inferior event-free survival (EFS, P = 0.005) and overall survival (OS, P<0.001) in univariate analysis. In multivariate analysis, high CD163 expression was strongly associated with inferior EFS (P = 0.043) and OS (P = 0.008). Patients with high MVD had a lower OS than those with low MVD, but the difference was not significant (P = 0.071, respectively). While high expression of CD68 was also associated with inferior EFS (P = 0.007), it showed no correlation with VEGF or MVD.

Conclusions

Our data confirms that CD163 expression provides independent prognostic information in cHL. The correlation of CD163 with VEGF expression and MVD suggests the role of CD163-positive cells in tumor angiogenesis of cHL.