Expression of tumor-associated macrophages and vascular endothelial growth factor correlates with poor prognosis of peripheral T-cell lymphoma, not otherwise specified

Therapeutic challenges in peripheral T-cell lymphoma

Peripheral T-cell lymphoma (PTCL) is a rare and heterogeneous group of hematological malignancies. Compared to our knowledge of B-cell tumors, our understanding of T-cell leukemia and lymphoma remains less advanced, and a significant number of patients are diagnosed with advanced stages of the disease. Unfortunately, the development of drug resistance in tumors leads to relapsed or refractory peripheral T-Cell Lymphomas (r/r PTCL), resulting in highly unsatisfactory treatment outcomes for these patients. This review provides an overview of potential mechanisms contributing to PTCL treatment resistance, encompassing aspects such as tumor heterogeneity, tumor microenvironment, and abnormal signaling pathways in PTCL development. The existing drugs aimed at overcoming PTCL resistance and their potential resistance mechanisms are also discussed. Furthermore, a summary of ongoing clinical trials related to PTCL is presented, with the aim of aiding clinicians in making informed treatment decisions.

Targeting Lymphoma-associated Macrophage Expansion via CSF1R/JAK Inhibition is a Therapeutic Vulnerability in Peripheral T-cell Lymphomas

The reciprocal relationship between malignant T cells and lymphoma-associated macrophages (LAM) within the tumor microenvironment (TME) is unique, as LAMs are well poised to provide ligands for antigen, costimulatory, and cytokine receptors that promote T-cell lymphoma growth. Conversely, malignant T cells promote the functional polarization and homeostatic survival of LAM. Therefore, we sought to determine the extent to which LAMs are a therapeutic vulnerability in these lymphomas, and to identify effective therapeutic strategies for their depletion. We utilized complementary genetically engineered mouse models and primary peripheral T-cell lymphoma (PTCL) specimens to quantify LAM expansion and proliferation. A high-throughput screen was performed to identify targeted agents that effectively deplete LAM within the context of PTCL. We observed that LAMs are dominant constituents of the TME in PTCL. Furthermore, their dominance was explained, at least in part, by their proliferation and expansion in response to PTCL-derived cytokines. Importantly, LAMs are a true dependency in these lymphomas, as their depletion significantly impaired PTCL progression. These findings were extrapolated to a large cohort of human PTCL specimens where LAM proliferation was observed. A high-throughput screen demonstrated that PTCL-derived cytokines led to relative resistance to CSF1R selective inhibitors, and culminated in the identification of dual CSF1R/JAK inhibition as a novel therapeutic strategy to deplete LAM in these aggressive lymphomas. Malignant T cells promote the expansion and proliferation of LAM, which are a bone fide dependency in these lymphomas, and are effectively depleted with a dual CSF1R/JAK inhibitor.

Significance

LAMs are a therapeutic vulnerability, as their depletion impairs T-cell lymphoma disease progression. Pacritinib, a dual CSF1R/JAK inhibitor, effectively impaired LAM viability and expansion, prolonged survival in preclinical T-cell lymphoma models, and is currently being investigated as a novel therapeutic approach in these lymphomas.

Significance of tumor-associated macrophages in bladder cancer development

Bladder cancer is the 2nd most common urological oncological disease in the worlds. Tumors can be muscle invasive and non-muscle invasive. Recently, tumor microenvironment (TME) became a focus of investigation in malignant tumors of the bladder. According to the currently available data, TME is a specific environment crating optimal conditions for carcinogenesis in the neoplastic lesion. The main parts of TME are extracellular matrix and stroma including vasculature, stromal, and immune cells. Additionally, TME includes cytokines, chemokines, and other compounds activating signal pathways necessary for tumor cells. Tumor-associated macrophages (TAMs) are being extensively studied as representatives of TME in solid tumors of varying locations. These macrophages can be classified into 2 phenotypes: M1 (pro-inflammatory and antitumor) and M2 (anti-inflammatory and protumor). The phenotypes perform different roles, and M2 macrophages regulate the most important processes of oncogenesis (invasion, proliferation, neoangiogenesis, etc.). In the context of bladder cancer, M2 macrophages are the most significant as they are the most numerous TAMs in TME.

Aim. To study the role of tumor-associated macrophages in development of bladder tumors, as well as prognostic value of these macrophages.

Deconvolution of Adult T-Cell Leukemia/Lymphoma With Single-Cell RNA-Seq Using Frozen Archived Skin Tissue Reveals New Subset of Cancer-Associated Fibroblast

Adult T-cell Leukemia/Lymphoma (ATLL) is a rare aggressive T-cell malignancy caused by human T-cell leukemia virus type 1 (HTLV-1) infection. However, little is known about the underlying activated molecular pathways at the single cell level. Moreover, the intercellular communications between the tumor microenvironment (TME) and tumor cells in this malignancy are currently unknown. Difficulties in harvesting fresh tissue in a clinical setting have hampered our deeper understanding of this malignancy. Herein, we examined ATLL using archived fresh frozen tissue after biopsy using single-cell RNA sequencing (scRNA-seq) with T-cell receptor (TCR) clonal analysis. Highly clonal tumor cells showed multiple activating pathways, suggesting dynamic evolution of the malignancy. By dissecting diverse cell types comprising the TME, we identified a novel subset of cancer-associated fibroblast, which showed enriched epidermal growth factor receptor (EGFR)-related transcripts including early growth response 1 and 2 (EGR1 and EGR2). Cancer associated fibroblasts (CAFs) of ATLL play an important role for CD4 T-cell proliferation via FGF7-FGF1 and PDGFA-PDGFRA/B signaling, and CAFs, particularly EGR-enriched, are also associated with CD8 and NKT expansion by EGFR. These findings suggest a potential targeted therapeutic pathway to better treat this neoplasm.

Tumor Associated Macrophages, as the Dominant Immune Cells, Are an Indispensable Target for Immunologically Cold Tumor-Glioma Therapy?

Tumor microenvironment (TME) is the cornerstone of the occurrence, development, invasion and diffusion of the malignant central nerve system (CNS) tumor, glioma. As the largest number of inflammatory cells in glioma TME, tumor associated macrophages (TAMs) and their secreted factors are indispensable to the progression of glioma, which is a well-known immunologically “cold” tumor, including the growth of tumor cells, invasion, migration, angiogenesis, cancer immunosuppression and metabolism. TAMs intimately interface with the treatment failure and poor prognosis of glioma patients, and their density increases with increasing glioma grade. Recently, great progress has been made in TAM-targeting for anti-tumor therapy. According to TAMs’ function in tumorigenesis and progression, the major anti-tumor treatment strategies targeting TAMs are to hinder macrophage recruitment in TME, reduce TAMs viability or remodel TAMs phenotype from M2 to M1. Different approaches offer unique and effective anti-tumor effect by regulating the phagocytosis, polarization and pro-tumor behaviors of macrophages in the therapy of glioma. The present review summarizes the significant characteristics and related mechanisms of TAMs and addresses the related research progress on targeting TAMs in glioma.

Role of Microenvironment in Non-Hodgkin Lymphoma: Understanding the Composition and Biology

Lymphoma microenvironment is a dynamic and well-orchestrated network of various immune and stromal cells that is indispensable for tumor cell survival, growth, migration, immune escape, and drug resistance. Recent progress has enhanced our knowledge of the pivotal role of microenvironment in lymphomagenesis. Understanding the characteristics, functions, and contributions of various components of the tumor niche, along with its bidirectional interactions with tumor cells, is paramount. It offers the potential to identify new therapeutic targets with the ability to restore antitumor immune surveillance and eliminate the protumoral factors contributed by the tumor niche.

Low serum cholesterol levels predict inferior prognosis and improve prognostic index scoring for peripheral T-cell lymphoma, unspecified

Peripheral T-cell lymphomas, unspecified (PTCL-U) is a heterogeneous group of non-Hodgkin lymphomas, arising from the transformation of mature, post-thymic T-cells. Prognostic index for PTCL-U (PIT) is based on Europeans and may not be applicable for Chinese PTCL-U patients. Besides, low circulating cholesterol concentration is associated with elevated cancer incidence and mortality. The purpose of our study was to assess the prognostic value of serum lipid levels in PTCL-U and improve PIT. We screened the prognostic factors associated with progression-free survival (PFS) and overall survival (OS) by multivariate Cox regression analysis in ninety-one enrolled patients. The results showed that low-level high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were associated with unfavorable OS. Furthermore, we developed a new risk model, PITC, based on low-level HDL-C, LDL-C and PIT. In Chinese PTCL-U, PITC was superior to PIT in PFS and OS. In conclusion, serum cholesterol levels may be good candidates for predicting prognosis in PTCL-U.

Tumor-associated macrophages: role in tumorigenesis and immunotherapy implications

Tumor-associated macrophages (TAMs) occupy an important position in the tumor microenvironment (TME), they are a highly plastic heterogeneous population with complex effects on tumorigenesis and development. TAMs secrete a variety of cytokines, chemokines, and proteases, which promote the remodeling of extracellular matrix, tumor cell growth and metastasis, tumor vessel and lymphangiogenesis, and immunosuppression. TAMs with different phenotypes have different effects on tumor proliferation and metastasis. TAMs act a pivotal part in occurrence and development of tumors, and are very attractive target to inhibit tumor growth and metastasis in tumor immunotherapy. This article reviews the interrelationship between TAMs and tumor microenvironment and its related applications in tumor therapy.

Enhancing antitumor immunity through checkpoint blockade as a therapeutic strategy in T-cell lymphomas

The majority of historical therapies for managing T-cell lymphomas (TCLs) have consisted of T-cell-depleting strategies. Unfortunately, these forms of therapies can hamper the ability to mount effective antitumor immune responses. Recently, the use of checkpoint inhibitors has revolutionized the therapy of solid and hematologic malignancies. The development of immunotherapies for the management of TCL has lagged behind other malignancies given 2 central reasons: (1) the competing balance of depleting malignant T cells while simultaneously enhancing an antitumor T-cell response and (2) concern for tumor hyperprogression by blocking inhibitory signals on the surface of the malignant T cell, thereby leading to further proliferation of the malignant cells. These challenges were highlighted with the discovery that programmed cell death protein 1 (PD-1) functions paradoxically as a haploinsufficient tumor suppressor in preclinical TCL models. In contrast, some preclinical and clinical evidence suggests that PD-1/programmed death ligand 1 may become an important therapeutic tool in the management of patients with TCL. Improved understanding of the immune landscape of TCL is necessary in order to identify subsets of patients most likely to benefit from checkpoint-inhibitor therapy. With increased preclinical research focus on the tumor microenvironment, substantial strides are being made in understanding how to harness the power of the immune system to treat TCLs. In this review, designed to be a "call to action," we discuss the challenges and opportunities of using immune-modulating therapies, with a focus on checkpoint inhibitors, for the treatment of patients with TCL.

Predicting worse survival for newly diagnosed T cell lymphoma based on the decreased baseline CD16-/CD16 + monocyte ratio

T cell non-Hodgkin lymphoma (T-NHL) is highly invasive and heterogeneous without accurate prognosis prediction. We proposed peripheral CD16-/CD16 + monocytes the additional indicators for T-NHL prognosis. We prospectively recruited 31 T-NHL patients without previous treatment. The CD16-/CD16 + monocyte ratio before chemotherapy was calculated and regular follow up was performed to calculate prognostic prediction value. Tumor associated macrophages (TAM) in tumor tissue were counted and transcriptome sequencing of CD16- and CD16 + monocytes was applied to explore potential mechanisms. We found that T-NHL patients had higher ratio of total monocytes especially the CD16 + monocytes along with a decreased ratio of CD16-/CD16 + monocytes, compared to the health control. The 1-year overall survival rate was 0.492 and 0.755 for CD16- monocyte/CD16 + monocyte ratio of <11 and ≥11(p < 0.05), respectively. The peripheral CD16-/CD16 + monocyte ratio was significantly relevant with the pathological CD68/CD206 macrophage ratio. The differently expressed genes in CD16- and CD16 + monocytes from T-NHL patients were mainly involved in signaling molecules related to tumor microenvironment. Pro-tumor genes were identified in monocyte subsets especially in CD16 + monocytes. In conclusion, the ratio of peripheral CD16-/CD16 + monocyte helps to stratify the prognosis of T-NHL. The relatively increased CD16 + monocytes may contribute to the pro-tumor microenvironment of T-NHL.

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.

Low absolute NK cell counts in peripheral blood are associated with inferior survival in patients with mantle cell lymphoma

BACKGROUND

Although risk stratification of mantle cell lymphoma (MCL) is most frequently performed using the simplified MCL International Prognostic Index (sMIPI), the identification of host-related factors and tumor microenvironment, including absolute monocyte counts (AMC) and peripheral blood T lymphocyte subsets, especially absolute natural killer cell counts (ANKC) has been suggested to be critical in the prediction of prognosis and the guidance of treatment.

OBJECTIVE

This study was aimed at investigating whether peripheral blood ANKC and AMC at diagnosis had an impact on MCL prognosis.

METHODS

A total of 92 newly diagnosed MCL patients was enrolled in this retrospective study. Flow cytometric analysis was conducted on fresh peripheral blood samples with a FACSCalibur flow cytometer (BD Biosciences, San Jose, CA, USA).

RESULTS

The median follow-up was 42 months (range, 2-144 months) and the median overall survival (OS) of all cases was 45 months. High AMC (> 0.6 × 109/L) was the parameter associated with inferior progression free survival (PFS) (P= 0.044) and poor OS (P= 0.028) while low ANKC (⩽ 0.1 × 109/L) was associated with unfavorable OS (P= 0.023) by univariable analysis. Multivariable analysis revealed that only low ANKC (⩽ 0.1 × 109/L) was statistically significant in worse OS (P= 0.009) independent of sMIPI.

CONCLUSIONS

Low ANKC (⩽ 0.1 × 109/L) proved to be a significant predictor of inferior OS in patients with MCL.

Absolute monocyte count is a predictor of overall survival and progression-free survival in nodal peripheral T cell lymphoma

Nodal peripheral T cell lymphomas (nPTCL) present aggressive clinical course, and its heterogeneous nature and poor prognosis with current therapeutic strategies make it a target for the development of new prognostic markers. Thus, we investigated tumor-associated macrophages (TAM) according to the number of cells expressing CD68 in biopsies and the absolute monocyte count (AMC) in peripheral blood of 87 patients with nPTCL. The median overall survival (OS) was 3 years (95% CI 1.3-8.4 years) and estimate 5 years OS of 43.3% (95% CI 32.5-53.7%). The median progression-free survival (PFS) was 1.5 years (95% CI 0.8-2.6 years) with estimate 5 years PFS of 29.2% (95% CI 19.7-39.3%). The cutoff for AMC was 1.5 × 10⁹/L and the median OS for patients with AMC ≥ 1.5 × 10⁹/L was 0.83 years versus 3.7 years for those with AMC < 1.5 × 10⁹/L (HR 2.32, 95% CI 1.03-5.22, p = 0.035). The median PFS for patients with AMC ≥ 1.5 × 10⁹/L was 0.50 years versus 1.5 years for those with AMC < 1.5 × 10⁹/L (HR 2.25, 95% CI 1.05-4.78, p = 0.031). CD68 was evaluated in 26/87 (29.8%) patients with a median expression of 34% and positivity cutoff of 43%. CD68 expression was not associated with OS or PFS either with AMC values. Our findings suggest that the AMC of ≥ 1.5 × 10⁹/L at diagnosis in peripheral blood is associated with poor prognosis in nPTCL. Further investigations in a larger cohort are required to better validate our results.

Mutual editing of alternative splicing between breast cancer cells and macrophages

Breast cancer is a highly heterogeneous disease and numerous secreted factors may differentially contribute to a macrophage phenotype whose extensive infiltration is generally regarded as indicative of an unfavorable outcome. How different breast tumor cells and macrophage cells interplay or influence each other on the alternative splicing (AS) level have not been characterized. Here, we exploited one previous study, which investigated the interplay between macrophages and estrogen receptor-positive (ER⁺) breast cancer and triple-negative breast cancer (TNBC) at the transcriptional level, to investigate the tumor-macrophage crosstalk at the AS level. In the present study, it was demonstrated that biological processes such as DNA damage and DNA repair were significantly affected both in ER⁺ breast cancer and TNBC by co-culturing with macrophages, whereas biological pathways altered in macrophages co-cultured with tumor cells depended on the breast cancer type. Specifically, biological processes altered in macrophages co-cultured with ER⁺ breast cancer were enriched in RNA processing and translation-related pathways whereas biological processes altered in macrophages co-cultured with TNBC were mainly enriched in protein transport pathways. We also analyzed the sequence features of skip exons among different conditions. In addition, putative splicing factors which were responsible for the altered AS profile in each condition were identified. The findings of the present study revealed significant tumor-macrophage crosstalk at the AS level which may facilitate the development of new therapeutic strategies for cancer.

Tumor Microenvironment in T-Cell Lymphomas

T-cell lymphomas (TCL) are uncommon non-Hodgkin lymphomas that often have an aggressive clinical course. Patients typically have limited treatment options upon relapse and a dismal prognosis after progression despite newly approved therapies. New therapeutic approaches for these orphan diseases are very much needed and a greater understanding of the role of nonmalignant immune cells in the tumor microenvironment may allow for an improved antitumor immune response. The tumor microenvironment is a key component in tumor evasion and typically results in an ineffective T-cell response to the tumor cells despite a significant inflammatory response. A better understanding of the tumor microenvironment therefore, in an effort to overcome the barriers to an effective immune response, would help in developing novel therapeutic approaches to treat and improve outcomes of these diseases. Immune checkpoint blockade to reinvigorate suppressed T-cell, or modulation of the CD47-SIRPalpha axis to promote macrophage phagocytosis, would be such targets. However, whether modulating the immune response using each pathway alone or whether a combination approach is necessary has yet to be determined.

Calcium Bisphosphonate Nanoparticles with Chelator-Free Radiolabeling to Deplete Tumor-Associated Macrophages for Enhanced Cancer Radioisotope Therapy

Tumor-associated macrophages (TAMs) are often related with poor prognosis after radiotherapy. Depleting TAMs may thus be a promising method to improve the radio-therapeutic efficacy. Herein, we report a biocompatible and biodegradable nanoplatform based on calcium bisphosphonate (CaBP-PEG) nanoparticles for chelator-free radiolabeling chemistry, effective in vivo depletion of TAMs, and imaging-guided enhanced cancer radioisotope therapy (RIT). It is found that CaBP-PEG nanoparticles prepared via a mineralization method with poly(ethylene glycol) (PEG) coating could be labeled with various radioisotopes upon simple mixing, including gamma-emitting ^99mTc for single-photon-emission computed tomography (SPECT) imaging, as well as beta-emitting ³²P as a therapeutic radioisotope for RIT. Upon intravenous injection, CaBP(^99mTc)-PEG nanoparticles exhibit efficient tumor homing, as evidenced by SPECT imaging. Owning to the function of bisphosphonates as clinical drugs to deplete TAMs, suppressed angiogenesis, normalized tumor vasculatures, enhanced intratumoral perfusion, and relieved tumor hypoxia are observed after TAM depletion induced by CaBP-PEG. Such modulated tumor microenvironment appears to be highly favorable for cancer RIT using CaBP(³²P)-PEG as the radio-therapeutic agent, which offers excellent synergistic therapeutic effect in inhibiting the tumor growth. With great biocompatibility and multifunctionalities, such CaBP-PEG nanoparticles constituted by Ca²⁺ and a clinical drug would be rather attractive for clinical translation.

GATA3 expression correlates with poor prognosis and tumor-associated macrophage infiltration in peripheral T cell lymphoma

Peripheral T cell lymphoma (PTCL) is an aggressive form of non-Hodgkin's lymphoma characterized by a poor prognosis. In this study, we examined the prognostic value of two T-cell-specific transcription factors, GATA3 and T-bet, in PTCL, uncovered the pathogenesis of PTCL, and investigated new PTCL therapeutic targets. Samples from 109 PTCL patients were examined for expression of GATA3, T-bet and CD68. High GATA3 expression correlated with poor survival in PTCL patients and with tumor-associated macrophage (TAM) infiltration, as indicated by the presence of CD68-positive cells. Multivariate analysis further confirmed that high GATA3 expression and Eastern Cooperative Oncology Group (ECOG) scores higher than 2 were independent predictors of patient survival. Using lentiviral transfection to induce stable GATA3 knockdown in a PTCL cell line, we observed that GATA-3 knockdown in Hut78 cells decreased levels of IL4, IL5, IL13 and VEGF mRNA and reduced the number of co-cultured U937 cells that differentiated towards the M2 phenotype. These results suggest that high GATA3 expression is a predictor of a poor prognosis in PTCL, and that T lymphoma cells promote M2-type macrophage differentiation through a GATA3-dependent mechanism.

TIE-2 expressing monocytes in human cancers

Tumor-associated macrophages (TAM) are well known as a key player in the tumor microenvironment, which support cancer progression. More recently, a lineage of monocytes characterized by the expression of the TIE-2/Tek angiopoietin receptor identified a subset of circulating and tumor-associated monocytes endowed with proangiogenic activity. TIE-2 expressing monocytes (TEM) were found both in humans and mice. Here, we review the phenotypes and functions of TEM reported so far in human cancer and their potential use as markers of cancer progression and metastasis. Finally, we discuss the therapeutic approaches currently used or proposed to target TEM.

Recombinant human endostatin in combination with CHOP regimen for peripheral T cell lymphoma

Peripheral T cell lymphoma (PTCL) has a poor prognosis. Overexpression of vascular endothelial growth factor (VEGF) might contribute to the poor prognosis of PTCL and could be the target of novel therapy. The efficacy and safety of recombinant human endostatin (Endostar) in combination with cyclophosphamide, doxorubicin, vincristine and prednisone (ECHOP) have been explored in 15 PTCL patients. The objective response rate was 80%, with 53.3% patients having achieved complete response (CR) rate. The CR rate was 100% (3/3) in angioimmunoblastic T cell lymphoma (AITL) patients compared to only 36.4% (4/11) in PTCL not otherwise specified (PTCL-NOS) patients. With a median follow-up of 69 months, the 5-year progression-free survival and overall survival (OS) were 53% and 60%, respectively. The 5-year OS was 100% in AITL but was only 45% in PTCL-NOS. Seven out of 11 patients showed overexpression of VEGFR2 in their tumor vessels and had a better efficacy than those with low expression of VEGFR2. Grade 3 or 4 neutropenia is the most common toxicity observed. ECHOP was safe and might display potential benefit in AITL patients.

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.

The role of alisertib in treatment of peripheral T-cell lymphomas

Peripheral T-cell lymphomas are aggressive lymphomas with poor outcomes for which novel treatments are urgently needed. Alisertib (MLN8237) is a second-generation oral Aurora A kinase inhibitor. Treatment with alisertib results in an accumulation of cells with abnormal mitotic spindles, leading to decreased proliferation and apoptosis in a range of human tumor cell lines. Alisertib has shown single-agent antitumor activity in animal xenograft models and promising antitumor activity alone or in combination with other agents in patients with solid and hematologic cancers, and T-cell lymphomas in particular. It is currently being tested in randomized controlled Phase III trials in relapsed/refractory peripheral T-cell lymphoma.

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.

CD68 expression is a discriminative feature of indolent cutaneous CD8-positive lymphoid proliferation and distinguishes this lymphoma subtype from other CD8-positive cutaneous lymphomas

BACKGROUND

Indolent cutaneous CD8+ lymphoid proliferation is a recently described rare entity among cutaneous T-cell lymphomas that typically presents with solitary skin lesions at acral sites. Separation from otherwise aggressive T-cell lymphomas bearing a cytotoxic CD8+ phenotype is fundamental to avoid unnecessary harmful treatment. However, up to now, no reliable discriminative marker has been identified.

OBJECTIVES

Motivated by these diagnostic quandaries, we have analyzed a large series of archived formalin-fixed paraffin-embedded (FFPE) specimens of atypical CD8+ cutaneous infiltrates with clear-cut diagnosis and clinical follow-up (n = 44) including five cases of indolent CD8+ lymphoid proliferation by using immunohistochemistry with the aim of obtaining markers predictive of subtype assignment.

RESULTS

We identified exclusive expression of CD68 by lymphoma cells within the subgroup of indolent CD8+ lymphoid proliferation (5/5 cases). Specific CD68 expression in this entity was confirmed by the application of several monoclonal antibodies (KP1, PG-M1, KiM1P) against the CD68 molecule available for FFPE tissue. In contrast, none of the infiltrates of the other CD8+ cutaneous lymphoma entities stained positive for CD68 (0/39).

CONCLUSIONS

Based on these observations, we suggest CD68 as a new discriminative marker which is helpful in distinguishing indolent CD8+ lymphoid proliferation from other CD8+ cutaneous lymphomas in ambiguous cases.

VEGF overexpression is a valuable prognostic factor for non-Hodgkin's lymphoma evidence from a systemic meta-analysis

Vascular endothelial growth factor (VEGF) plays a vital role in the progression of Non-Hodgkin's lymphoma (NHL). Although multiple studies have investigated the relationship between VEGF expression and prognosis of NHL, these studies have yielded conflicting results. Therefore, we performed a meta-analysis to evaluate the role of VEGF in the prognosis of NHL patients. We systematically searched eligible studies from databases and determined that there was a significant correlation between VEGF overexpression and overall survival (HR (hazard ratio) = 1.66, 95% CI: 1.25–2.22, P = 0.001). Based on subgroup analysis by study location, number of patients, the source of VEGF expression, and study design, we found that VEGF overexpression in surgically resected tissue (HR = 1.95, 95% CI: 1.41–2.69, P = 0.000), but not in serum (HR = 1.37, 95% CI: 0.96–1.95, P = 0.087), was associated with poorer prognosis. Additionally, VEGF overexpression did not correlate with performance status, LDH level, IPI score, tumor staging, B symptoms, or NHL relapse. In summary, overexpression of VEGF in lymphoma tissue represents a promising potential prognostic factor in NHL.

Integrin αvβ3 acting as membrane receptor for thyroid hormones mediates angiogenesis in malignant T cells

The interaction of lymphoid tumor cells with components of the extracellular matrix via integrin αvβ3 allows tumor survival and growth. This integrin was demonstrated to be the membrane receptor for thyroid hormones (THs) in several tissues. We found that THs, acting as soluble integrin αvβ3 ligands, activated growth-related signaling pathways in T-cell lymphomas (TCLs). Specifically, TH-activated αvβ3 integrin signaling promoted TCL proliferation and angiogenesis, in part, via the upregulation of vascular endothelial growth factor (VEGF). Consequently, genetic or pharmacologic inhibition of integrin αvβ3 decreased VEGF production and induced TCL cell death in vitro and in human xenograft models. In sum, we show that integrin αvβ3 transduces prosurvival signals into TCL nuclei, suggesting a novel mechanism for the endocrine modulation of TCL pathophysiology. Targeting this mechanism could constitute an effective and potentially low-toxicity chemotherapy-free treatment of TCL patients.

High intratumoral macrophage content is an adverse prognostic feature in anaplastic large cell lymphoma

AIMS

Macrophage infiltration has been associated with prognosis in several cancers, including lymphoma, but has not been assessed systematically in anaplastic large cell lymphoma (ALCL). The aim of the study was to correlate expression of the macrophage-associated antigens CD68 and CD163 with pre-therapeutic parameters and outcome in a cohort of treatment-naive ALCL patients.

METHODS AND RESULTS

Pre-therapeutic tumour specimens from 52 patients with ALCL were included in a tissue microarray. The intratumoral macrophage content was assessed by immunohistochemical staining for CD68 and CD163, and quantified using digital image analysis. Anaplastic lymphoma kinase (ALK)-positive patients were significantly younger and had a favourable outcome compared with ALK-negative ALCL patients (median age: 42 versus 59 years; P = 0.008). However, ALK expression was not a significant predictor when adjusting for age. Although classical risk factors were distributed evenly between the compared groups, high intratumoral content of CD68 and/or CD163 correlated with poor outcome, in both univariate and multivariate analyses. High intratumoral CD163 content showed the strongest adverse association with both overall and progression-free survival in ALK-negative patients (P < 0.001).

CONCLUSIONS

A high content of intratumoral CD68- and/or CD163-positive macrophages correlates with an adverse outcome in ALK-negative ALCL.

Bevacizumab and cyclosphosphamide, doxorubicin, vincristine and prednisone in combination for patients with peripheral T-cell or natural killer cell neoplasms: an Eastern Cooperative Oncology Group study (E2404)

Peripheral T-cell lymphoma (PTCL) and natural killer (NK) cell lymphoma have poor survival with conventional cytotoxic chemotherapy. Because angiogenesis plays an important role in the biology of PTCL, a fully humanized anti-vascular endothelial growth factor (VEGF) antibody, bevacizumab (A), was studied in combination with standard cyclosphosphamide, doxorubicin, vincristine and prednisone (CHOP) chemotherapy (ACHOP) to evaluate its potential to improve outcome in these patients. Patients were treated with 6-8 cycles of ACHOP followed by eight doses of maintenance A (15 mg/kg every 21 days). Forty-six patients were enrolled on this phase 2 study from July 2006 through March 2009. Forty-four patients were evaluable for toxicity and 39 were evaluable for response, progression and survival. A total of 324 cycles (range: 2-16, median 7) were administered to 39 evaluable patients and only nine completed all planned treatment. The overall response rate was 90% with 19 (49%) complete response/complete response unconfirmed (CR/CRu) and 16 (41%) a partial response (PR). The 1-year progression-free survival (PFS) rate was 44% at a median follow-up of 3 years. The median PFS and overall survival (OS) rates were 7.7 and 22 months, respectively. Twenty-three patients died (21 from lymphoma, two while in remission). Grade 3 or 4 toxicities included febrile neutropenia (n = 8), anemia (n = 3), thrombocytopenia (n = 5), congestive heart failure (n = 4), venous thrombosis (n = 3), gastrointestinal hemorrhage/perforation (n = 2), infection (n = 8) and fatigue (n = 6). Despite a high overall response rate, the ACHOP regimen failed to result in durable remissions and was associated with significant toxicities. Studies of novel therapeutics are needed for this patient population, whose clinical outcome remains poor.

Hypoxia-related gene expression profile in childhood acute lymphoblastic leukemia: prognostic implications

A cellular hypoxic condition is a key event in several human cancers, but knowledge about its role in childhood acute lymphoblastic leukemia (ALL) is very limited. In the present study, the gene expression profile of hypoxia-related genes (HIF1A, CA9, VEGF and SCL2A1) was evaluated in bone marrow samples of 113 pediatric patients. HIF1A mRNA up-regulation was significantly associated with higher 5-year event-free survival rates in patients with B-ALL as well as in the overall ALL population in both univariate and multivariate analysis (p = 0.023 and p = 0.041, respectively). In gene expression analysis, low oxygen levels promoted HIF1A activation in a time-dependent manner, in both ALL cell lines. In vitro cytotoxic assays suggested an initial trend toward hypoxia-related resistance in the first 24 h, but evaluation at later time points (48-72 h) clearly showed that there was no relevant difference in drug response when comparing hypoxic and normal oxygen level conditions. Modulation of mRNA expression of several hypoxia-related genes was also observed after hypoxic exposure in a cell specific manner, suggesting that HIF1A mRNA expression could play a different role in specific subtypes of leukemia. Despite the remaining questions regarding hypoxia-mediated mechanisms, these findings could be helpful to provide new insights into the role of hypoxia in childhood ALL.

The microenvironment in T-cell lymphomas: emerging themes

Peripheral T-cell lymphomas (PTCLs) are heterogeneous and uncommon malignancies characterized by an aggressive clinical course and a mostly poor outcome with current treatment strategies. Despite novel insights into their pathobiology provided by recent genome-wide molecular studies, several entities remain poorly characterized. In addition to the neoplastic cell population, PTCLs have a microenvironment component, composed of non-tumor cells and stroma, which is quantitatively and qualitatively variable, and which may have an effect on their pathological and clinical features. The best example is provided by angioimmunoblastic T-cell lymphoma (AITL), a designation reflecting the typical vascularization and reactive immunoblastic content of the tumor tissues. In this disease, a complex network of interactions between the lymphoma cells and the microenvironment exists, presumably mediated by the neoplastic T cells with follicular helper T-cell properties. A better understanding of the crosstalk between neoplastic T or NK cells and their microenvironment may have important implications for guiding the development of novel therapies.

Carcinoma-associated fibroblasts, its implication in head and neck squamous cell carcinoma: a mini review

The communication between tumor stromal and parenchymal cells provides an insight to tumor progression. One of the main elements of the stroma, a major contributor to the extracellular environment of tumors, is carcinoma-associated fibroblasts. They can originate from either normal fibroblasts in the immediate vicinity of the tumor or from circulating bone marrow-derived mesenchymal stem cells. These myofibroblasts can arise locally from an endothelial-mesenchymal transformation at the invasive edge of the cancer and are physically associated with carcinoma cells, that is, in the development of high-grade malignancies and poor prognosis. These carcinoma-associated fibroblasts feed the epithelial tumor cells in a host-parasite relationship establishing its role in head and neck squamous cell carcinoma progression.

High numbers of tumor-associated macrophages correlate with poor prognosis in patients with mature T- and natural killer cell lymphomas

Various studies on lymphoma microenvironment have demonstrated the prognostic impact of tumor-associated macrophages (TAMs) in patients with B-cell lymphoma. Little is known about the correlation between TAMs and treatment outcome in mature T- and natural killer (NK) cell lymphomas. We analyzed the prognostic relevance of CD68+ TAMs by immunohistochemical analysis in 64 Chinese patients with mature T- and NK-cell lymphomas. Higher number of infiltrated TAMs was significantly related to B symptoms and extranodal involvement (p < 0.05). The TAMs content did not differ significantly between pathological subtypes. Using the mean value of TAMs per high-power field (hpf) as the cutoff point (87/hpf), 36 cases (56.2 %) were categorized as low level of TAMs content and 28 cases (43.8%) as high level. Patients with high level of TAMs content had a worse 5-year overall survival compared to those with low level (28.1 vs. 44.3 %, p = 0.039). In multivariate analysis, TAMs content remained an independent biological variable for survival distinct from the International Prognostic Index (Cox multivariate model, p = 0.009). High TAMs content indicated an adverse overall outcome in mature T- and NK-cell lymphomas. Our results show that expression of stromal TAMs may become a useful marker for prognosis of mature T- and NK-cell lymphomas.

Role of bone marrow-derived cells in angiogenesis: focus on macrophages and pericytes

Tumor growth relies on the formation of new blood vessels to receive an adequate supply of oxygen and nutrient. This process is facilitated by both the remodeling of the pre-existing vasculatures and the recruitment of the progenitor/stem cells originated from bone marrow-derived cells (BMDCs). Evidences from both animal studies and human trials have reported that these tumor-associated BMDCs differentiate into a series of stromal cells including macrophages and pericytes, and regulate tumor angiogenesis in various aspects. Macrophages constitute a large portion of the BMDCs infiltrated in the tumor microenvironment, and have been shown to disrupt the balance of pro- and anti-angiogenic signalings by the secretion of various cytokines. Pericytes, mainly derived from the subpopulation of PDGFRβ(+) BMDCs, can provide both pro-survival signaling and mechanical support to maintain the newly formed endothelium via the direct interactions with endothelial cells. In the current review, we summarize the recruitment mechanisms of BMDC-derived macrophages and pericytes within tumor microenvironment, and also review the contribution of these cells to the different aspects of angiogenesis, with particular emphasis on their therapeutic implications as potential targets for anti-tumor strategies.

Increased CCL18 expression in patients with cutaneous T-cell lymphoma: association with disease severity and prognosis

BACKGROUND

CC chemokine ligand (CCL) 18 is expressed by monocytes and dendritic cells (DCs), and has potent chemotactic activity for T cells, B cells and DCs. CCL18 expression is up-regulated in lesional skin of atopic dermatitis and bullous pemphigoid, suggesting its important roles in the development of these skin diseases.

OBJECTIVE

To investigate roles of CCL18 in cutaneous T-cell lymphoma (CTCL).

METHODS

The CCL18 messenger RNA (mRNA) expression in CTCL skin (n = 21) and in normal skin (n = 7) was examined by quantitative RT-PCR. CCL18 expression was also examined by immunohistochemistry. Serum CCL18 levels were measured in 38 patients with CTCL and 20 healthy controls by enzyme-linked immunosorbent assay. We also analysed correlation between serum CCL18 levels and other clinical and laboratory data.

RESULTS

The CTCL lesional skin contained higher levels of CCL18 mRNA than normal skin. CCL18 was expressed by dermal macrophages and DCs in CTCL skin. Serum CCL18 levels in patients with CTCL were significantly higher than those of healthy controls and correlated with types of skin lesions. They also significantly correlated with modified severity-weighted assessment scores, serum sIL-2R, LDH, IL-4, IL-10, IL-31, CCL17 and CCL26 levels. Patients with high serum levels of CCL18 showed significantly poor prognosis compared with those with low CCL18 levels.

CONCLUSION

CCL18 mRNA is up-regulated in CTCL lesional skin, and serum CCL18 levels are significantly increased and correlated with the severity of CTCL. These results suggest that CCL18 may be associated with the development of CTCL.

The tumor microenvironment

The concept of the tumor microenvironment, developed from Paget's "seed and soil" theory is made up of the cancer cells, the stromal tissue, and the extracellular matrix. In this mini-review, each of the components of this dynamic network will be examined. We will show that there are a multitude of complex interactions and a host of molecules involved in tumorogenesis and metastasis. We will further illustrate this notion with examples from the tumor microenvironment of breast cancer. Lastly, we conclude with thoughts about how this will influence the surgical field with examples of therapeutic agents already in use that target aspects of this microenvironment.

Prognostic significance of neuron-specific enolase in patients with diffuse large B-cell lymphoma treated with rituximab-based immunochemotherapy

The present study examined the clinical significance of serum neuron-specific enolase (NSE) in patients with diffuse large B-cell lymphoma (DLBCL). Serum NSE values were measured using a electrochemiluminescence assay in 106 patients and tissue NSE expression was examined using immunohistochemistry in 65 patients. Fifty-four percent of patients had a positive expression of serum NSE (>15.20 ng/mL), and cytoplasmic NSE was pathologically demonstrated in 26/65 cases, which showed a positive correlation with that of serum NSE expression. The serum NSE value was closely correlated with performance status, serum lactate dehydrogenase (LDH) level, International Prognostic Index (IPI) score, and Ann Arbor stage, and declined significantly in patients who responded to treatment. In the rituximab-immunochemotherapy group, there was a significant difference in the 5-year overall survival (OS) rate between the NSE-positive and -negative groups (93% vs. 44%, p = 0.001), and the serum NSE level was found to be an independent prognostic factor. Serum NSE may be a novel marker of disease aggressiveness as well as a prognostic factor for DLBCL in the era of rituximab.