Tumor-associated Macrophages In Patients Research Articles

Immunohistochemical diagnosis of tumor-associated macrophages in patients with muscle-invasive bladder cancer after radical cystectomy

BACKGROUND: Bladder cancer is a serious problem of oncourology. The gold standard of treatment for muscle-invasive bladder cancer is radical cystectomy with previous neoadjuvant chemotherapy. Unfortunately, the effectiveness of radical treatments is severely limited in the long term. For this reason, research in the field of predicting survival can significantly improve long-term oncological results. The determination of the levels of macrophages associated with the tumor appears promising.
 AIM: to determine the effect of the expression levels of macrophages associated with a tumor on survival rates in patients diagnosed with muscle-invasive bladder cancer after radical cystectomy.
 MATERIALS AND METHODS: the study was conducted on the basis of the Clinic of the Bashkir State Medical University in the period from 01.05.2021 to 01.07.2023. The study involved 66 patients with an established diagnosis of muscle-invasive bladder cancer. After surgical treatment, histological and immunohistochemical studies were performed to determine CD68 and CD163 levels. After 24 months, a survival analysis was performed to determine the levels of general, tumor-specific and relapse-free survival and the construction of Kaplan–Mayer graphs.
 RESULTS: According to the results of the analysis, there was a significant decrease in survival in groups with high CD68 and CD163 expression rates (p 0.05). In the study groups, there was a significantly significant correlation between high levels of CD68 and CD163 (p 0.05).
 CONCLUSIONS: CD68 and CD163 can act as independent markers of predicted survival in patients with muscle-invasive bladder cancer after radical cystectomy.

Commentary on the publication of Yargunin S.A. et al. “Dynamics of changes in tumor-associated macrophages in patients with primary skin melanoma depending on the method of surgical treatment”

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Dynamics of changes in tumor-associated macrophages in patients with primary skin melanoma depending on the method of surgical treatment

Summary: Skin melanoma is one of the deadliest among human skin tumors, and surgery remains the first and main method in its combined treatment. Despite the seemingly radical nature of surgical interventions in patients with primary skin melanoma, the frequency of locoregional recurrence and metastasis remains high. The question of the impact of surgical treatment on the evolution of the melanoma microenvironment remains unclear.Aim: to investigate the dynamics of polarization in tumor-associated macrophages in patients with primary skin melanoma of stage 0-IIa and in subsequent metastatic lesions to assess the impact of postoperative ischemia on survival of patients.Results: it was found that in patients with primary skin melanoma of stage 0-IIa plastic replacement of a tissue defect, compared with conventional suturing, can lead to a decrease in the density in the intrastromal distribution of pro-inflammatory CD68 + macrophages in the surgical focus, as well as less frequent polarization of TAM cells in the M2 direction and migration to the intrastromal component of the tumor, their more frequent mixed content, which, as a result, affects the survival of this category of patients for the better.Conclusions: plastic closing a surgical defect in patients with primary skin melanoma of stage 0-IIa may affect the duration of postoperative ischemia and the polarization of TAM cells. Plastic replacement of a tissue defect after tumor removal improves five-year survival rates (PFS by 22,6 % (p = 0.003) and OS by 13,1% (p = 0.029).

Retraction: Clinicopathologic and prognostic significance of tumor-associated macrophages in patients with hepatocellular carcinoma: A meta-analysis.

Retraction: Clinicopathologic and prognostic significance of tumor-associated macrophages in patients with hepatocellular carcinoma: A meta-analysis.

Prognostic significance of tumor-associated macrophages in patients with nasopharyngeal carcinoma: A meta-analysis.

Background:To explore the prognostic value of diverse subsets of tumor-associated macrophages (TAMs) in prognosis in patients with nasopharyngeal carcinoma (NPC) using meta-analysis.Methods:Relevant studies were searched in the database of PubMed, Web of Science, Embase, Cochrane Library, Scopus, China National Knowledge Infrastructure (CNKI), and Wanfang till November 2019. The relationship between TAMs and survival outcomes was estimated by pooling hazard ratios (HRs) and 95% confidence intervals (CIs); and the correlation of TAMs and clinicopathological factors was evaluated by using odds ratios (ORs) and 95%CIs.Results:Six studies with 1549 patients were included in this meta-analysis. The high expression of CD68+ TAMs was associated with favorable disease-free survival (DFS) (HR = 0.66, 95%CI = 0.50–0.88, P = .005), whereas the density of M2-like TAMs (CD163+, CD68+CCL18+, and CD206+) was correlated to poor overall survival (OS) (HR = 1.77, 95%CI = 1.22–2.56, P = .003) and DFS (HR = 1.96, 95%CI = 1.00–3.85, P = .050) in patients with NPC.Conclusions:CD68+ TAM density is associated with superior DFS, while CD163+ M2-like TAMs predicted poor prognosis in patients with NPC.

The prognostic and clinicopathological value of tumor-associated macrophages in patients with colorectal cancer: a systematic review and meta-analysis.

There is a growing literature on the significance of tumor-associated macrophages (TAMs) in colorectal cancer (CRC). However, the role of TAMs in predicting the prognosis of CRC remains controversial. The current study aims to determine the prognostic and clinicopathological value of different types and distribution of TAMs in CRC. A comprehensive literature search of PubMed, Embase, and Cochrane Library databases was conducted from the inception to 1 September 2019. The correlations of TAMs with overall survival (OS), disease-free survival (DFS), cancer-specific survival (CSS), and clinicopathological characteristics were analyzed. A total of 5,575 patients from 29 studies were included in this meta-analysis. The pooled hazard ratios (HRs) indicated that high density of pan-macrophages in tumor invasive margin (IM) was associated with better OS (HR = 0.57, 95%CI = 0.38-0.85), DFS (HR = 0.32, 95%CI = 0.19-0.52), and CSS (HR = 0.56, 95%CI = 0.41-0.77). Moreover, the high density of pan-macrophages in tumor center (TC) was correlated with better DFS (HR = 0.66, 95%CI = 0.45-0.96). However, high expression of M2 macrophages in TC was associated with poor DFS (HR = 2.42, 95%CI = 1.45-4.07) and CSS (HR = 1.74, 95%CI = 1.24-2.44). High M2 macrophages density in IM was also associated with short DFS (HR = 2.81, 95%CI = 1.65-4.77). In addition, the results showed that high density of pan-macrophages in IM was associated with no tumor metastasis, while high M2 macrophages density in TC was correlated with poor tumor differentiation. High Pan-TAMs density in IM has a positive effect on the prognosis of CRC patients, while high density M2 macrophage infiltration in TC is a strong indicator of poor prognosis.

GATA3 as a master regulator for interactions of tumor-associated macrophages with high-grade serous ovarian carcinoma

High-grade serous ovarian carcinoma (HGSOC) is the most lethal gynecologic cancer. Emerging evidence suggests that tumor-associated macrophages (TAMs) play an immunosuppressive role in the tumor microenvironment and promote tumor growth, angiogenesis, and metastasis in ovarian cancer. Therefore, targeting TAMs in patients with ovarian cancer is an appealing strategy; however, all trials to date have failed. To improve the efficacy of this approach, we sought to elucidate the underlying mechanisms of the role of TAMs in ovarian cancer. We found that the developmental transcription factor GATA3 was highly expressed in HGSOC cell lines but not in the fallopian tube, which is the main origin of HGSOC. GATA3 expression was associated with poor prognosis in HGSOC patients (P < .05) and was found to promote proliferation and migration in HGSOC cell lines. GATA3 was released abundantly from TAM cells via exosomes and contributed to tumor growth in the tumor microenvironment. Moreover, GATA3 acted as a regulator for macrophage polarization and interactions between TAMs and HGSOC to support proliferation, motility, and cisplatin chemoresistance in mutant TP53 HGSOC cell lines. Furthermore, GATA3 played a critical role in the interactions between TAMs and mutant TP53 HGSOC to promote angiogenesis and epithelial-mesenchymal transition with epigenetic regulation. Targeting GATA3 using GATA3siRNA in TAMs impeded GATA3-driven proliferation, migration, cisplatin chemoresistance, and angiogenesis in mutant TP53 HGSOC cell lines. Our findings indicate that GATA3 plays a novel role in immunoediting of HGSOC and demonstrate that GATA3 may serve as a prognostic marker for HGSOC and a promising target in the treatment of HGSOC.

Clinicopathologic and prognostic significance of tumor-associated macrophages in patients with hepatocellular carcinoma: A meta-analysis.

Tumor-associated macrophages (TAMs) deserve more focus because of its clinicopathologic and prognostic roles in solid tumors. However, the prognostic value of TAMs in patients with hepatocellular carcinoma (HCC) is still controversial. We performed a meta-analysis to resolve the issue. We selected relevant studies from the Cochrane Library, Embase and PubMed databases. The hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated employing fixed-effect or random-effect models depending on the heterogeneity of the included trials. Moreover, we also performed subgroup analysis, cumulative meta-analysis, sensitivity analysis, and bias analysis (Egger's test). A total of 20 observational studies with 4297 patients were enrolled. For TAMs subsets, high density of CD68+ TAMs in either intratumor (IT) (pooled HR = 1.417; 95% CI = 1.092-1.839; P = 0.009) or peritumor (PT) (pooled HR = 1.393; 95% CI = 1.022-1.899; P = 0.036) was associated with a poor OS. High density of CD68+ TAMs in IT was also associated with high AFP value, large tumor size, absent encapsulation, present vascular invasion, and later tumor-nodes-metastasis (TNM) stage. High density of CD163+ macrophages in serum was associated with a poor OS (pooled HR = 5.698; 95% CI = 3.062-10.603; P < 0.001). High density of CD204+ TAMs in IT was associated with a poor OS (pooled HR = 1.947; 95% CI = 1.387-2.733; P < 0.001. High density of CD206+ TAMs in IT was associated with a poor OS (pooled HR = 1.723; 95% CI = 1.308-2.270; P < 0.001) and DFS (pooled HR = 1.711; 95% CI = 1.214-2.412; P = 0.002). However, high density of CD169+ TAMs in IT was associated with a good OS (pooled HR = 0.471; 95% CI = 0.343-0.647; P = 0.037). TAMs could serve as independent predictive indicators and therapeutic targets for HCC. Further trials are needed to elucidate the exact relationship and the underlying mechanism.

Prognostic implications of tumor associated macrophages (TAMs) in soft tissue sarcoma.

e22548 Background: Clinical responses in patients with soft tissue sarcoma administered immune checkpoint inhibitors have been infrequent. Little is known regarding the immune microenvironment in soft tissue sarcoma that leads to a lack of effective responses with immune therapies. Whilst several studies have shown T cell infiltration in sarcomas, these tumors do not respond to immunotherapies. Macrophages are important regulators of immune responses in the tumor microenvironment. Studies in mouse models indicate that macrophages regulate immune checkpoint inhibitor response. With the overall goal of developing more effective combination immunotherapies for sarcoma, we examined tumor associated macrophages in patients with soft tissue sarcoma administered neoadjuvant chemotherapy. Interactions between macrophage infiltration, tumor immunogenicity and overall survival were also assessed using publicly available RNAseq and exome mutation data. Methods: Immunohistochemistry was performed on formalin fixed soft tissue sarcoma tissue. Tissues from 20 patients with soft tissue sarcoma pre and post neo-adjuvant chemotherapy were included. TAMs were detected by CD68; M2 subtype were detected by CD163. CD4, CD8, and CD25 T cells were also examined. The density of CD68+ TAMs, CD163+ TAMs and the ratio of CD163+ TAMs / CD68+ TAMs were calculated and their correlation with survival was also made. Publicly available RNAseq and exome mutation data were assembled from The Cancer Genome Atlas (TCGA) sarcoma cohort (n = 259). For each tumor, a relative measure of abundance of tumor-infiltrating macrophages was estimated using gene expression. Tumor mutational burden (TMB), expressed as the rate of non- synonymous mutations per megabase of sequenced DNA, was used as a measure of tumor immunogenicity. Interactions between macrophage infiltration, tumor immunogenicity and overall survival were assessed by Cox regression and Kaplan-Meier analysis. Categorical relationships involving clinical, immunologic, and genomic features of the tumor immune subclasses were compared. Results: Specific alteration in the density of CD68+ TAMs, CD163+ TAMs, and the CD163 / CD68 ratio were observed in patients with soft tissue sarcoma responding to neoadjuvant chemotherapy. Categorical relationships involving macrophage infiltration, TMB, and survival were also observed. Conclusions: These study support the targeting of tumor associated macrophages in patients with soft tissue sarcoma and suggest that changes in TAMs may be achievable using neoadjuvant chemotherapy.

In Vivo MR Imaging of Tumor-Associated Macrophages: The Next Frontier in Cancer Imaging.

There is a complex interaction between cancer and the immune system. Tumor-associated macrophages (TAMs) can be subverted by the cancer to adopt a pro-tumor phenotype to aid tumor growth. These anti-inflammatory, pro-tumor TAMs have been shown to contribute to a worsened outcome in several different types of cancer. Various strategies aimed at combating the pro-tumor TAMs have been developed. Several therapies, such as oncolytic viral therapy and high-intensity focused ultrasound, have been shown to stimulate TAMs and suppress tumor growth. Targeting TAMs is a promising way to combat cancer, but sensitive imaging methods that are capable of detecting these therapeutic responses are needed. A promising idea is to use imaging contrast agents to label TAMs to determine their relative number and location within, and around the tumor. This can provide information about the efficacy of TAM depletion therapies, as well as macrophage-stimulating therapies. In this review, we describe various in vivo MRI methods capable of tracking TAMs, and conclude with a short section on tracking TAMs in patients.

Prognostic value of diametrically polarized tumor-associated macrophages in multiple myeloma.

Tumor-associated macrophages (TAMs) are correlated with the prognosis of different types of solid tumors and lymphoma, according to many clinical studies. In vitro experiments have demonstrated the roles of these cells in myeloma cell survival, angiogenesis, immunomodulation, drug resistance, and the interaction between malignant myeloma cells and the microenvironment. Here, we investigated the prognostic significance of TAMs in patients with multiple myeloma (MM). We evaluated the polarized functional status of bone marrow infiltrated by TAMs by immunohistochemical staining of CD68, iNOS, and CD163 in 240 patients with MM from January 2009 to December 2014. The overall response rates to chemotherapy were lower in patients with high CD68+ or CD163+ TAM densities than in those with low densities. Kaplan-Meier analysis showed that the progression-free survival (PFS, p = 0.001) and overall survival (OS, p < 0.001) of patients with low CD163+ TAM density were significantly higher than those of patients with high CD163+ TAM density. Furthermore, combined analysis of iNOS+ and CD163+ TAMs (iNOS/CD163 signature) exhibited greater power in predicting patient outcomes for both PFS (p < 0.001) and OS (p < 0.001). Moreover, Cox regression analysis identified iNOS+ and CD163+ TAMs as independent prognostic factors (p = 0.007, p < 0.001, respectively). These factors could be combined with the international staging system (ISS) to generate a predictive nomogram for patient outcomes. Our findings suggest that the mosaic of diametrically polarized TAMs is a novel independent prognostic factor that could be integrated into the evaluation of and therapy for MM.

578 Immunomodulatory effects of bexarotene on tumor-associated macrophages in patients with mycosis fungoides

578 Immunomodulatory effects of bexarotene on tumor-associated macrophages in patients with mycosis fungoides

The Prognostic and Clinicopathological Significance of Tumor-Associated Macrophages in Patients with Gastric Cancer: A Meta-Analysis.

ObjectiveComprehensive studies have investigated the prognostic and clinicopathological value of tumor-associated macrophages (TAMs) in gastric cancer patients, yet results remain controversial. Therefore, we performed a meta-analysis to clarify this issue.MethodsPubMed, Embase, and the Cochrane Library databases were searched to identify eligible studies. We extracted hazard ratios (HRs) and odds ratios (ORs) with their corresponding 95% confidence intervals (95% CIs) to estimate the effect sizes. In addition, subgroup analysis and sensitivity analysis were also conducted.ResultsA total of 19 studies involving 2242 patients were included. High generalised TAMs density was significantly associated with poor overall survival (OS) (HR 1.49, 95% CI 1.15–1.95). Subgroup analysis revealed that CD68+ TAMs had no significant effect on OS (HR 1.38, 95% CI 1.00–1.91). High M1 TAMs density was correlated with better OS (HR 0.45, 95% CI 0.32–0.65). By contrast, high density of M2 TAMs was correlated with a poor prognosis for OS (HR 1.48, 95% CI 1.25–1.75). Furthermore, high M2 TAMs density was correlated with larger tumor size, diffuse Lauren type, poor histologic differentiation, deeper tumor invasion, lymph node metastasis, and advanced TNM stage.ConclusionsOverall, this meta-analysis reveal that although CD68+ TAMs infiltration has the neutral prognostic effects on OS, the M1/M2 polarization of TAMs are predicative factor of prognosis in gastric cancer patients.

Abstract 2371: The number of CD163-positive cells in the microenvironment and peripheral blood lymphocyte-to-monocyte-ratio (LMR) is associated with poor outcome in patients with diffuse large B-cell lymphoma (DLBCL)

Abstract Purpose: Despite advances in treatment, 30-40% of the DLBCL patients succumb to their disease. The prognostic role of peripheral blood absolute monocyte count (AMC), LMR and tumor-associated macrophages (TAM) in DLBCL has previously been suggested. However, information on the association of LMR/AMC and TAM is limited. We performed this study to evaluate the association and prognostic role of LMR/AMC and TAM in patients with DLBCL treated at our institute. Patients and Method: 76 patients with newly diagnosed DLBCL were selected. CD163 expression was assessed by immunohistochemistry using tissue microarray. The number of CD163 positive nucleated cells at objective magnification of 40x were counted and were divided into 4 categories: score 0 (0-25 cells); score 1 (26-50); score 2 (51-75); score 3 (&amp;gt;75). Results: The median age of the patients was 62 (range: 27-87) years-old. 38 patients (52.4%) were advanced stage (stage 3/4), and 47.3% of patients had germinal center (GC) phenotype. The median AMC at the time of diagnosis was 408 (range: 42-1,107)/mm3, and the median LMR was 2.94 (0.64-14.06). CD163 staining was scored as follows: score 0: 13 patients (17.1%), score 1: 7 patients (9.2%), score 2: 6 patients (7.9%), score 3: 50 patients (65.8%). There was a trend for higher stage (p = 0.08) and non-GC type histology (p = 0.05) in patients with CD163 score 3. Although there was no difference in AMC between those with CD163 score 0-2 and 3, CD163 score 3 was significantly associated with lower LMR (LMR&amp;lt;2.77; p = 0.011). Of the patients who received treatment (n = 68), 43.4% of the patients were treated with a rituximab containing regimen (R(+)). 16 (R(+):5, R(-):11) patients died after a median observation of 6.2 (0.1-21.6) years. LMR&amp;lt;2.77, and CD163 score 3 were associated with adverse prognosis in R(-) patients (p = 0.0032, 0.0084) but not in R(+) (p = 0.92, 0.37) patients. Conclusion: We have confirmed in our patients with newly diagnosed DLBCL who received chemotherapy without rituximab, that LMR and the number of CD163-positive cells are significant prognostic factors. Contrary to previous reports, neither TAM as characterized by CD163-positive cells in the microenvironment or LMR/AMC were prognostic factors in R(+) patients. Of interest, higher number of TAM was associated with lower LMR. Further evaluation is needed to confirm this finding and its clinical relevance. Citation Format: Eri Matsuki, Olga L. Bohn, Janine Pichardo, Andrew Zelenetz, Anas Younes, Julie Teruya-Feldstein. The number of CD163-positive cells in the microenvironment and peripheral blood lymphocyte-to-monocyte-ratio (LMR) is associated with poor outcome in patients with diffuse large B-cell lymphoma (DLBCL). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2371. doi:10.1158/1538-7445.AM2015-2371

Expression of Cathepsin L in tumor cells and tumor-associated macrophages in patients with Ewing sarcoma family of tumors: a pilot study.

Cysteine protease Cathepsin L is involved in bone remodeling and expressed in activated macrophages. It is highly expressed in metastatic tumor tissue, especially with bone metastases. We evaluated immunohistochemical expression of Cathepsin L in tumor cells and tumor-associated macrophages (TAMs) in chemo-naive Ewing sarcoma. Retrospective evaluation of archived specimens of Ewing sarcoma. Immunohistochemical staining was performed on archived blocks of chemo-naive patients with Ewing sarcoma treated with uniform chemotherapy at our institute between January 2009 and November 2011. Immunohistochemical expression was co-related with baseline demographics and survival. During the study period, we had evaluable baseline samples from 62 patients with median age 15 years (range: 2-40); 26 (42%) had metastases. Cathepsin L expression in tumor cells was observed in 8/62 (13%) specimens. None of the baseline clinical characteristics correlated with Cathepsin L expression. Cathepsin L positivity was associated with poor response to neoadjuvant chemotherapy (NACT) (P = 0.05), but did not influence either event-free-survival (EFS) or overall survival. Cathepsin L was expressed in TAMs in all specimens. Grade 3 TAMs (>10 TAMs/high power field) was associated with better response to NACT (P = 0.05). On univariate analysis Grade 3 TAMs predicted superior EFS (median EFS 28.5 months in those with Grade 3 TAMs versus 14.8 months in those with grade ½ TAMs [P = 0.04]). Cathepsin L expression by immunohistochemistry was low in our patient cohort, and it did not affect the outcome. In addition, Grade 3 TAMs with Cathepsin L expression was associated with improved EFS.

High infiltration of tumor-associated macrophages in triple-negative breast cancer is associated with a higher risk of distant metastasis.

BackgroundTriple-negative breast cancer (TNBC) is associated with poor prognosis and high probability of distant metastases. Tumor microenvironments play a pivotal role in tumor metastasis. Tumor-associated macrophages (TAMs) are one of the main cell components, and they are correlated with increasing metastatic risk. The aim of this study is to analyze the prognostic significance of the infiltration of TAMs in patients with TNBC.Materials and methodsImmunohistochemical staining for cluster of differentiation (CD)68 (a marker for macrophages) was performed on tissue microarrays of operable breast cancer among 287 patients with TNBC, and the number of infiltrating TAMs was correlated with clinicopathological parameters.ResultsWe found that TNBC with a large number of infiltrating TAMs had a significantly higher risk of distant metastasis, as well as lower rates of disease-free survival and overall survival than those with a smaller number of infiltrating TAMs. Multivariate analysis indicated that the number of infiltrating TAMs was a significant independent prognostic factor of disease-free survival (P=0.001) in all patients.ConclusionOur results suggested that high infiltrating TAMs are a significantly unfavorable prognostic factor for patients with TNBC, and they could become a potentially useful prognostic marker for TNBC.

Histological characterization of tumor-associated macrophages in patients with different stages of hepatocellular carcinoma (HCC) (TUM4P.914)

Abstract Tumor-associated macrophages, major leukocytes detected in tumor tissues, have been characterized as M2Mφ. Recently, M2Mφ have been classified into different subsets; M2aMφ, M2bMφ and M2cMφ. Therefore, in this study, the subset of M2Mφ present in tumor tissues of HCC patients was determined. Tumor tissues were obtained by liver biopsy and liver resection from patients with early and advanced stages of HCC. Paraffin embedded tissue specimens were stained for PE-conjugated anti-CD68 Ab. Also, the same tissue specimens were stained for FITC-conjugated anti-IL-12 Ab, PE-conjugated anti-IL-10 Ab, FITC-conjugated anti-CCL1 Ab, and FITC-conjugated anti-CD206 Ab. Stained histologic specimens were examined microscopically. In the results, large numbers of CD68+cells were predominantly present in the edge of the tumors. Large numbers of Mφ were not isolated from the tumor nests. CD68+cells isolated from advanced stage HCC patients were determined as IL-10+CD206+ cells, while a few numbers of these cells were demonstrated in the tumor tissues of early stage HCC patients. IL-10+CCL1+ cells and IL-12+CD68+ cells were not isolated from both advanced stage and early stage HCC patients. These results indicate that a majority of M2Mφ present in advanced stage HCC patients are M2aMφ and/or M2cMφ.

Macrophages inhibit human osteosarcoma cell growth after activation with the bacterial cell wall derivative liposomal muramyl tripeptide in combination with interferon-γ

BackgroundIn osteosarcoma, the presence of tumor-infiltrating macrophages positively correlates with patient survival in contrast to the negative effect of tumor-associated macrophages in patients with other tumors. Liposome-encapsulated muramyl tripeptide (L-MTP-PE) has been introduced in the treatment of osteosarcoma patients, which may enhance the potential anti-tumor activity of macrophages. Direct anti-tumor activity of human macrophages against human osteosarcoma cells has not been described so far. Hence, we assessed osteosarcoma cell growth after co-culture with human macrophages.MethodsMonocyte-derived M1-like and M2-like macrophages were polarized with LPS + IFN-γ, L-MTP-PE +/− IFN-γ or IL-10 and incubated with osteosarcoma cells. Two days later, viable tumor cell numbers were analyzed. Antibody-dependent effects were investigated using the therapeutic anti-EGFR antibody cetuximab.ResultsM1-like macrophages inhibited osteosarcoma cell growth when activated with LPS + IFN-γ. Likewise, stimulation of M1-like macrophages with liposomal muramyl tripeptide (L-MTP-PE) inhibited tumor growth, but only when combined with IFN-γ. Addition of the tumor-reactive anti-EGFR antibody cetuximab did not further improve the anti-tumor activity of activated M1-like macrophages. The inhibition was mediated by supernatants of activated M1-like macrophages, containing TNF-α and IL-1β. However, specific blockage of these cytokines, nitric oxide or reactive oxygen species did not inhibit the anti-tumor effect, suggesting the involvement of other soluble factors released upon macrophage activation. While LPS + IFN-γ–activated M2-like macrophages had low anti-tumor activity, IL-10–polarized M2-like macrophages were able to reduce osteosarcoma cell growth in the presence of the anti-EGFR cetuximab involving antibody-dependent tumor cell phagocytosis.ConclusionThis study demonstrates that human macrophages can be induced to exert direct anti-tumor activity against osteosarcoma cells. Our observation that the induction of macrophage anti-tumor activity by L-MTP-PE required IFN-γ may be of relevance for the optimization of L-MTP-PE therapy in osteosarcoma patients.

Macrophages and Mast Cells Infiltration Are Biomarkers of Primary Refractory Hodgkin's Lymphoma

AbstractAbstract 3881Classical Hodgkin's lymphoma is a highly curable lymphoma and about 80% of patients can be cured with modern treatment strategies. In spite of great clinical progress, a significant minority of classical Hodgkin's lymphoma experiences treatment failure after primary chemotherapy including a first line of anthracyclin-based regimen. Patients with refractory Hodgkin's lymphoma represent 5 to 10% of classical Hodgkin's Lymphoma. Many of these patients have a poor overall survival estimated at 25% at 5 years. A better biological characterization of such primary refractory patients might allow the use of early therapeutic intervention including targeted therapy. It remains, however, a challenge to identify patients whose disease will not be eradicated by standard therapy. Current prognostic models predict the outcome of treatment with imperfect accuracy, and clinically relevant biomarkers have not yet been established to improve the International Prognostic Score. For these reasons, reliable biomarkers for predicting long term survival at diagnosis are needed for such patients. Steidl et al. (Nejm,2010) recently reported the prognostic value of tumor-associated macrophages in patients with classical Hodgkin's lymphoma, showing that higher infiltration is associated with a shortened survival.The value of tumor-associated macrophages in primary refractory Hodgkin's lymphomas has not been specifically assessed. In a retrospective study (Canioni et al., Plos one 2009), we previously evaluated 59 patients (18 with primary refractory or early relapse disease and 41 responders) collected from 1997 to 2004 in two hematology centres (Necker Hospital and Gustave Roussy Institute, Paris France) for c-kit expression by immunohistochemical analysis as a marker of mast cell infiltration and correlated the results with the response to treatment. All available poor prognosis patients were first identified (18 patients with primary refractory disease or early relapse (< 1year)) and the control group (47 responders) was randomly selected. Patients received conventional chemotherapy-based treatments [(MOPP (mechlorethamine, vincristine, procarbazine, and prednisone), ABVD (doxorubicine, bleomycine, vinblastine, and dacarbazine) or the combination of both or BEACOPP (bleomycine, etoposide, doxorubicine, cyclophosphamide, vincristine, procarbazine, prednisone)] and radiotherapy in stages I and II. Most patients presented a nodular sclerosis subtype of Hodgkin's lymphoma regardless whether they were refractory (17/18cases, 94.5%) or responders (37/41cases, 90%). In this cohort, 44 (75%) patients had a localized stage, whereas 19 (25%) had a disseminated disease. The results showed that refractory Hodgkin's lymphoma were associated with an excess of mast cells infiltration in the tumor cells microenvironment. The number of mast cells stained was significantly higher in refractory Hodgkin's lymphoma (c-kit+ mast cells > 6 per field) than in responders (c-kit+ mast cells ≤ 6) (p=0.001 and 0.0194 in univariate and multivariate analysis, respectively). In this cohort of patients, using CD68 staining we also found a statistically significant higher proportion of tumor-associated macrophages in refractory Hodgkin's lymphoma as compared to responders in univariate and multivariate analyses (p=0.0048 and p=0.0041, respectively). Therefore, we confirmed a strong correlation between the number of CD68 positive macrophages in the tumor stroma and clinical outcome. The use of such markers (CD68 and c-kit) in combination with well-established clinical risk factors could improve on the predictive value of a single biomarker used alone.Therefore, in addition to mast cells, macrophages are also important players in refractory Hodgkin's lymphoma that may confer drug resistance to Hodgkin Reed Sternberg cells. Taken together, these data strongly suggest that microenvironment should be targeted in Hodgkin's lymphomas. In this regard, the use of kinase inhibitors that target both c-kit and M-CSF receptors could restore chemotherapy sensitivity in refractory Hodgkin's lymphoma and should be evaluated in clinical trials. Disclosures:No relevant conflicts of interest to declare.

Expression of CD68+ tumor‐associated macrophages in patients with diffuse large B‐cell lymphoma and its relation to prognosis

Tumor-associated macrophages (TAM) have been ascribed both pro- and anti-tumor properties, but the majority of clinical cancer studies have shown that the presence of a high number of TAM is related to poor prognosis, suggesting that TAM predominantly exert pro-tumoral activity. The prognostic role of TAM in patients with diffuse large B-cell lymphoma (DLBCL), however, is so far unknown. Therefore, TAM were immunohistochemically stained with a CD68 antibody in a retrospective, population-based study including 176 DLBCL patients treated with curative intent. With the exception that patients >60 years of age had a larger number of CD68+ cells (1143 vs 1018 cells/mm2; P = 0.05), no significant differences were found between the number of CD68+ cells and other clinical factors. Similarly, germinal center B-cell (GCB)/non-GCB immunophenotype or low/high Ki-67 percentage were not associated with CD68 expression. Finally, no significant correlation was found between the number of CD68+ cells and progression-free survival (P = 0.34) or overall survival (P = 0.94). These data indicate that the pro-tumor effect of TAM has limited clinical relevance in DLBCL patients, which could imply that therapeutic strategies aimed at enhancing their anti-tumor activity are of continuous clinical interest.