Macrophage polarisation changes within the time between diagnostic biopsy and tumour resection in oral squamous cell carcinomas--an immunohistochemical study

Minimally invasive biopsy-based diagnostics in support of precision cancer medicine

Precision cancer medicine (PCM) to support the treatment of solid tumors requires minimally invasive diagnostics. Here, we describe the development of fine-needle aspiration biopsy-based (FNA) molecular cytology which will be increasingly important in diagnostics and adaptive treatment. We provide support for FNA-based molecular cytology having a significant potential to replace core needle biopsy (CNB) as a patient-friendly potent technique for tumor sampling for various tumor types. This is not only because CNB is a more traumatic procedure and may be associated with more complications compared to FNA-based sampling, but also due to the recently developed molecular methods used with FNA. Recent studies show that image-guided FNA in combination with ultrasensitive molecular methods also offers opportunities for characterization of the tumor microenvironment which can aid therapeutic decisions. Here we provide arguments for an increased implementation of molecular FNA-based sampling as a patient-friendly diagnostic method, which may, due to its repeatability, facilitate regular sampling that is needed during different treatment lines, to provide tumor information, supporting treatment decisions, shortening lead times in healthcare, and benefit healthcare economics.

Neoadjuvant Radiochemotherapy Alters the Immune and Metabolic Microenvironment in Oral Cancer-Analyses of CD68, CD163, TGF-β1, GLUT-1 and HIF-1α Expressions

BACKGROUND

The first-line treatment of oral squamous cell carcinoma (OSCC) involves surgical tumor resection, followed by adjuvant radio(chemo)therapy (R(C)T) in advanced cases. Neoadjuvant radio- and/or chemotherapy has failed to show improved survival in OSCC. Recently, neoadjuvant immunotherapy has shown promising therapeutic efficacy in phase 2 trials. In this context, the addition of radio- and chemotherapy is being reconsidered. Therefore, a better understanding of the tumor-biologic effects of neoadjuvant RCT would be beneficial. The current study was conducted on a retrospective cohort of patients who received neoadjuvant RCT for the treatment of oral cancer. The aim of the study was to evaluate the influence of neoadjuvant RCT on the immunological tumor microenvironment (TME) and hypoxic and glucose metabolisms.

METHODS

A cohort of 45 OSSC tissue samples from patients were analyzed before and after RCT (total 50.4 Gy; 1.8 Gy 5× weekly; Cisplatin + 5-Fluorouracil). Immunohistochemistry for CD68, CD163, TGF-β, GLUT-1 and HIF-1α was performed using tissue microarrays and automated cell counting. Differences in expression before and after RCT and associations with histomorphological parameters (T-status, N-status) were assessed using the Mann-Whitney U test.

RESULTS

Tumor resection specimens after neoadjuvant RCT showed a significant decrease in CD68 infiltration and a significant increase in CD163 cell density. The CD68/CD163 ratio was significantly lower after RCT, indicating a shift toward M2 polarization. The GLUT-1 and HIF-1α expressions were significantly lower after RCT. Larger tumors (T3/T4) showed a lower GLUT-1 expression. Other biomarkers were not associated with the T- and N-status.

CONCLUSIONS

Neoadjuvant RCT with 50.4 Gy induced a shift toward the M2 polarization of macrophages in the TME. This change in immune composition is not favorable and may be prognostically negative and counteract immunotherapeutic approaches. In addition, the decreased expressions in GLUT-1 and HIF-1α indicate reductions in the glucose metabolism and hypoxic energy metabolism in response to "high dose" neoadjuvant RCT, which may be therapeutically desirable.

Macrophages in head and neck squamous cell carcinoma: A bibliometric analysis

INTRODUCTION

The tumor microenvironment in head and neck squamous cell carcinoma (HNSCC) is densely infiltrated by macrophages. Utilizing bibliometric analysis, the characteristics, hotspots for research, and research frontiers related to macrophages in HNSCC were reviewed.

METHODS

The Web of Science Core Collection database was queried for relevant articles published from 2000 to 2022. VOSviewer and CiteSpace software were utilized to evaluate and visualize macrophage-related HNSCC research trends and hotspots.

RESULTS

Assessment of original articles revealed that the annual number of publications regarding the role of macrophages in HNSCC has increased steadily over the past 23 years. China produced the most articles, whereas the United States had the highest number of citations and highest H-index. Wuhan University and Oral Oncology were the most productive affiliation and journal, respectively. The paper published by Bray et al in the CA-A Cancer Journal for Clinicians in 2018 had the greatest number of citations. The keywords "expression," "cancer," and "tumor-associated macrophages (TAMs)" occurred most frequently.

CONCLUSIONS

This bibliometric investigation discovered that publications about macrophages in HNSCC are steadily increasing. The majority of studies focused on macrophage polarization, macrophage markers, and inflammation in the tumor microenvironment. Furthermore, our bibliometric analysis revealed that the immunosuppressive role of tumor-associated macrophages in the tumor microenvironment and resistance to therapy in HNSCC have recently received attention.

Postoperative Changes in Systemic Immune Tolerance Following Major Oncologic versus Minor Maxillofacial Surgery

BACKGROUND

There is increasing evidence of the benefits of adjuvant and neoadjuvant immunotherapy in the treatment of solid malignancies like oral squamous cell carcinoma (OSCC). To optimize (neo-)adjuvant treatment, the systemic immunomodulatory effects of tumor surgery itself need to be considered. Currently, there is little evidence on the immunological effects of major surgery, such as free microvascular flap reconstruction. The current study aims to analyze how and to what extent maxillofacial surgery affects systemic parameters of immune tolerance.

METHODS

A total of 50 peripheral whole blood samples from patients (Group 1 (G1) = extensive OSCC surgery; Group 2 (G2) = free flap reconstruction without persistent malignant disease; Group 3 (G3) = minor maxillofacial surgery) undergoing surgery were included for real-time quantitative polymerase chain reaction (RT-qPCR) to examine changes in mRNA expression of the biomarkers IL-6, IL-10, FOXP3, and PD-L1. Blood samples were taken immediately before and after surgery as well as on the second, fourth, and tenth postoperative days. Differences in mRNA expression between groups and time points were calculated using statistical tests, including Mann-Whitney U-test and Pearson correlation analysis.

RESULTS

Comparing postoperative expression of G1 and G3, there was a significantly higher PD-L1 expression (p = 0.015) in G1 compared to G3 and a significantly lower IL-6 (p = 0.001) and FOXP3 (p = 0.016) expression. Interestingly, IL-10 expression was higher pre- (0.05) and postoperative (p < 0.001) in G1 compared to G3. Additionally, in G1, there was a significant overexpression of IL-10 post-surgery compared to the preoperative value (p = 0.03) and a downregulated expression of FOXP3 between pre- and 2 d post-surgery (p = 0.04). Furthermore, there was a significant correlation between the duration of surgery and the perioperative expression changes of the analyzed biomarkers. As the duration of surgery increased, the expression of IL-10 and PD-L1 increased, and the expression of IL-6 and FOXP3 decreased.

CONCLUSION

Extensive surgery in OSCC patients is associated with a transient shift toward postoperative systemic immune tolerance compared with patients undergoing minor surgery. However, even extensive surgery causes no signs of long-lasting systemic immunosuppression. The degree of immune tolerance that occurred was associated with the duration of surgery. This supports efforts to minimize the duration of surgery.

Increased breast cancer mortality due to treatment delay and needle biopsy type: a retrospective analysis of SEER-medicare

BACKGROUND

Substantial evidence indicates that delay of first treatment after diagnosis is associated with poorer survival outcomes in breast cancer. Accordingly, the Commission on Cancer introduced a quality measure for receipt of therapeutic surgery within 60 days of diagnostic biopsy for stage I-III breast cancer patients in the non-neoadjuvant setting. It is unknown, however, what may contribute to mortality associated with treatment delay. Therefore, we investigated whether biopsy type moderates the effect of the mortality risk posed by treatment delay.

METHODS

Retrospective analysis of 31,306 women with stage I-III breast cancer diagnosed between 2003 and 2013 selected from the SEER-Medicare database was performed to determine whether needle biopsy type [core needle biopsy (CNB) or vacuum-assisted biopsy (VAB)] impacts time to treatment (TTT)-associated survival outcomes. Multivariable Fine-Gray competing risk survival models, adjusted for inverse propensity score weights, were used to determine the association between biopsy type, TTT, and breast cancer-specific mortality (BCSM).

RESULTS

TTT ≥ 60 days was associated with 45% higher risk of BCSM (sHR = 1.45, 95% CI 1.24-1.69) compared to those with TTT < 60 days in stage I-III cases. Independent of TTT, CNB was associated with 28% higher risk of BCSM compared to VAB in stage II-III cases (sHR = 1.28, 95% CI 1.11-1.36), translating to a 2.7% and 4.0% absolute difference in BCSM at 5 and 10 years, respectively. However, in stage I cases, the BCSM risk was not associated with type of biopsy.

CONCLUSIONS

Our results suggest that treatment delay ≥ 60 days is independently associated with poorer survival outcomes in breast cancer patients. In stage II-III, CNB is associated with higher BCSM than VAB. However, type of biopsy does not underlie TTT-associated breast cancer mortality risk.

The role of tumor-associated macrophages in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a common head and neck cancer with a high recurrence rate and a low 5-year survival rate. Tumor-associated macrophages (TAMs) are important immune cells in the tumor microenvironment, which play an important role in the progression of many tumors. This article reviews the origin, and the role of TAMs in the invasion, metastasis, angiogenesis and immunosuppression of OSCC. Therapeutic strategies targeting TAMs are also discussed in hopes of providing new ideas for the treatment of OSCC.

Neutrophils Promote Glioblastoma Tumor Cell Migration after Biopsy

Glioblastoma is diagnosed by biopsy or, if clinically feasible, tumor resection. However, emerging evidence suggests that this surgical intervention may increase the risk of tumor cell spread. It has been hypothesized that the damage to the tumor leads to infiltration of immune cells that consequently form an environment that favors tumor cell motility. In mouse glioma models, it was previously found that biopsy induced migration of tumor cells in vivo and that recruitment of monocytes from the blood was involved in this effect. However, the role of neutrophils in this process is still unclear. Here, we study the contribution of neutrophils on the pro-migratory effect of surgical interventions in glioma. Using repetitive intravital microscopy, in vivo migration of glioma tumor cells before and after biopsy was compared in mice systemically depleted of neutrophils. Interestingly, macrophages/microglia were almost completely absent from neutrophil-depleted tumors, indicating that neutrophils may be indirectly involved in biopsy-induced migration of glioma tumor cells through the recruitment of macrophages to the tumor. To further investigate whether neutrophils have the potential to also directly promote glioblastoma tumor cell migration, we performed in vitro migration assays using human neutrophils. Indeed, wound-healing of human primary glioblastoma tumor cell lines was promoted by human neutrophils. The pro-migratory effects of human neutrophils on glioblastoma tumor cells could also be recapitulated in transwell migration assays, indicating that soluble factor(s) are involved. We therefore provide evidence for both an indirect and direct involvement of neutrophils in tumor spread following biopsy of glioblastoma tumors.

Macrophage and T-Cell Infiltration and Topographic Immune Cell Distribution in Non-Melanoma Skin Cancer of the Head and Neck

Non-melanoma skin cancer (NMSC) is a heterogeneous tumor entity that is vastly determined by age and UV-light exposure leading to a great mutational burden in cancer cells. However, the success of immune checkpoint blockade in advanced NMSC and the incidence and disease control rates of NMSC in organ transplant recipients compared to immunologically uncompromised patients point toward the emerging importance of the immunologic activity of NMSC. To gain first insight into the role of T-cell and macrophage infiltration in NMSC of the head and neck and capture their different immunogenic profiles, which appear to be highly relevant for the response to immunotherapy, we conducted a whole slide analysis of 107 basal cell carcinoma (BCC) samples and 117 cutaneous squamous cell carcinoma (cSCC) samples. The CD8⁺ and CD68⁺ immune cell expression in both cancer types was evaluated by immunohistochemistry and a topographic distribution profile, and the proportion of both cell populations within the two tumor entities was assessed. The results show highly significant differences in terms of CD8⁺ T-cell and CD68⁺ macrophage infiltration in BCC and cSCC and indicate cSCC as a highly immunogenic tumor. Yet, BCC presents less immune cell infiltration; the relation between the immune cells compared to cSCC does not show any significant difference. These findings help explain disparities in local aggressiveness, distant metastasis, and eligibility for immune checkpoint blockade in both tumor entities and encourage further research.

Targeting Myeloid-Derived Suppressor Cells Derived From Surgical Stress: The Key to Prevent Post-surgical Metastasis

Myeloid-derived suppressor cells (MDSCs) are known to play an essential part in tumor progression under chronic stress settings through their manipulation of adaptive and innate immune systems. Previous researches mainly focus on MDSC's role in the chronic tumor immune environment. In addition, surgery can also serve as a form of acute stress within the patient's internal environment. Nevertheless, the part that MDSCs play in post-surgical tumor development has not gained enough attention yet. Although surgery is known to be an effective definite treatment for most localized solid tumors, there are still plenty of cancer patients who experience recurrence or metastasis after radical resection of the primary tumor. It is believed that surgery has the paradoxical capability to enhance tumor growth. Many possible mechanisms exist for explaining post-surgical metastasis. We hypothesize that surgical resection of the primary tumor can also facilitate the expansion of MDSCs and their pro-tumor role since these surgery-induced MDSCs can prepare the pre-metastatic niche (the "soil") and at the same time interact with circulating tumor cells (the "seeds"). This vicious, reciprocal mechanism is a crucial point in the emergence of post-surgical metastasis. According to our hypothesis, MDSCs can be the precise target to prevent cancer patients from post-surgical recurrence and metastasis during the perioperative phase to break the wretched cycle and provide better long-term survival for these patients. Future studies are needed to validate this hypothesis.

The Colorectal Cancer Tumor Microenvironment and Its Impact on Liver and Lung Metastasis

Simple Summary

Colorectal cancer (CRC) is the third most common cancer worldwide. Metastasis to secondary organs, such as the liver and lungs, is a key driver of CRC-related mortality. The tumor microenvironment, which consists of the primary cancer cells, as well as associated support and immune cells, significantly affects the behavior of CRC cells at the primary tumor site, as well as in metastatic lesions. In this paper, we review the role of the individual components of the tumor microenvironment on tumor progression, immune evasion, and metastasis, and we discuss the implications of these components on antitumor therapies.

Abstract

Colorectal cancer (CRC) is the third most common malignancy and the second most common cause of cancer-related mortality worldwide. A total of 20% of CRC patients present with distant metastases, most frequently to the liver and lung. In the primary tumor, as well as at each metastatic site, the cellular components of the tumor microenvironment (TME) contribute to tumor engraftment and metastasis. These include immune cells (macrophages, neutrophils, T lymphocytes, and dendritic cells) and stromal cells (cancer-associated fibroblasts and endothelial cells). In this review, we highlight how the TME influences tumor progression and invasion at the primary site and its function in fostering metastatic niches in the liver and lungs. We also discuss emerging clinical strategies to target the CRC TME.

Neuronal CD200 Signaling Is Protective in the Acute Phase of Ischemic Stroke

BACKGROUND AND PURPOSE

CD200 (cluster of differentiation 200), a highly glycosylated protein primarily expressed on neurons in the central nervous system, binds with its receptor CD200R to form an endogenous inhibitory signal against immune responses. However, little is known about the effect of neuronal CD200 signaling in cerebral ischemia. The aim of this study was to investigate how neuronal CD200 signaling impacts poststroke inflammation and the ischemic injury.

METHODS

CD200 tma1^lf/fl:Thy1CreER mice were treated with tamoxifen to induce conditional gene knockout (ICKO) of neuronal CD200. The mice were subjected to a 60-minute transient middle cerebral artery occlusion. Stroke outcomes, apoptotic cell death, immune cell infiltration, microglia activation, and other inflammatory profiles were evaluated at 3 and 7 days after stroke.

RESULTS

Infarct volumes were significantly larger, and behavioral deficits more severe in ICKO versus control mice at 3 days after middle cerebral artery occlusion. Terminal deoxynucleotidyl transferase dUTP nick end labeling assay also revealed a significant increase in apoptotic neuronal death in CD200 ICKO mice. An enhancement in lymphocytic infiltration and microglial proinflammatory responses were revealed by flow cytometry at 3 and 7 days after stroke in ICKO mice, accompanied by an increased microglial phagocytosis activity. Plasma proinflammatory cytokine (TNFα [tumor necrosis factor alpha] and IL [interleukin]-1β) levels significantly increased at 3 days, and IL-1β/IL-6 levels increased at 7 days in ICKO versus control animals. ICKO led to significantly lower baseline level of CD200 both in brain and plasma.

CONCLUSIONS

Neuronal CD200 inhibits proinflammatory responses and is protective against stroke injury.

Pro-Tumorigenic Macrophage Infiltration in Oral Squamous Cell Carcinoma and Possible Macrophage-Aimed Therapeutic Interventions

In Oral Squamous Cell Carcinomas (OSCC), as in other solid tumors, stromal cells strongly support the spread and growth of the tumor. Macrophages in tumors (tumor-associated macrophages or “TAMs”), can swing between a pro-inflammatory and anti-tumorigenic (M1-like TAMs) state or an anti‐inflammatory and pro-tumorigenic (M2-like TAMs) profile depending on the tumor microenvironment cues. Numerous clinical and preclinical studies have demonstrated the importance of macrophages in the prognosis of patients with different types of cancer. Here, our aim was to review the role of M2-like TAMs in the prognosis of patients with OSCC and provide a state of the art on strategies for depleting or reprogramming M2-like TAMs as a possible therapeutic solution for OSCC. The Clinical studies reviewed showed that higher density of CD163+ M2-like TAMs associated with worse survival and that CD206+ M2-TAMs are involved in OSCC progression through epidermal growth factor (EGF) secretion, underlining the important role of CD206 as a marker of OSCC progression and as a therapeutic target. Here, we provide the reader with the current tools, in preclinical and clinical stage, for depleting M2-like TAMs, re-educating them towards M1-like TAMs, and exploiting TAMs as drug delivery vectors.

Alteration of Macrophage Infiltrating Compartment: A Novel View on Oral Carcinogenesis

BACKGROUND

The mortality of oral squamous cell carcinoma (OSCC) has remained high for decades; therefore, methods for early detection of OSCC are warranted. However, in the oral cavity, various mucosal diseases may be encountered, including reactive lesions and oral potentially malignant disorders, and it is difficult to differentiate OSCC from these lesions based on both clinical and histopathological findings. It is well known that chronic inflammation contributes to oral cancer development. Macrophages are among the most common inflammatory cells in cancer stromal tissue and have various roles in cancer aggressiveness. Although the roles of macrophages in cancer development have attracted attention, only a few studies have linked macrophages to carcinogenesis, particularly, oral precancerous lesions.

SUMMARY

This review article consists of 3 parts: first, we summarize current knowledge on macrophages in human various epithelial precancerous lesions, excluding the oral cavity, to show the importance and gaps in knowledge regarding macrophages in carcinogenesis; second, we review published data related to the role of macrophages in oral carcinogenesis; finally, we present a novel view on oral carcinogenesis, focusing on crosstalk between epithelial cells and macrophages. Key Messages: The biological features of macrophages in oral carcinogenesis differ drastically depending on the anatomical compartment that they infiltrate. Focusing on the alteration of macrophage infiltrating compartment may serve as a useful novel approach for studying the role of the macrophages in oral carcinogenesis and for gaining further insight into cancer prevention and early detection.

Immuno-Oncological Biomarkers for Squamous Cell Cancer of the Head and Neck: Current State of the Art and Future Perspectives

The era of immune checkpoint inhibitors has altered the therapeutic landscape in squamous cell cancer of the head and neck (SCCHN). Our knowledge about the tumor microenvironment has fueled the research in SCCHN, leading to several well-known and less-known prognostic and predictive biomarkers. The clinical staging, p16/HPV status, and PD-L1 expression are currently the main tools for assessing the patients' diagnosis and prognosis. However, several novel biomarkers have been thoroughly investigated, some reaching actual significant clinical contributions. The untangling of the immune infiltrate with the subtyping of tissue-associated tumor infiltrating lymphocytes, tumor-associated macrophages, and circulating blood-based biomarkers are an interesting avenue to be further explored and prospectively assessed. Although PD-L1 expression remains the most important response predictor for immune checkpoint inhibitors, several flaws impede proper assessment such as technical issues, different scoring protocol, and intra-, inter-, and temporal heterogeneity. In addition, the construction of an immune-related gene panel has been proposed as a prognostic and predictive stratification but lacks consensus. Recently, the role of microbioma have also been explored regarding its systemic and antitumor immunity. This review gives a comprehensive overview of the aforementioned topics in SCCHN. To this end, the integration of these clinically advantageous biomarkers via construction of an immunogram or nomogram could be an invaluable tool for SCCHN in future prospects.

The prospects of nanotherapeutic approaches for targeting tumor-associated macrophages in oral cancer

OSCC (oral squamous cell carcinoma) is currently one of the most formidable cancers plagued by challenges like low overall survivability, lymph node associated metastasis, drug resistance, and poor diagnostics. The tumor microenvironment (TME) and its constituent stromal elements are crucial modulators of tumor growth and treatment response, more specifically so with regards to resident tumor associated macrophages (TAMs) and their liaison with the different stromal elements in the tumor niche (Figure 1). Interestingly, there isn't much information on TAM-targeted nanotherapy in OSCC where the first line of therapeutics for oral cancer is surgery with other therapeutics such as chemo- and radiotherapy acting only as adjuvant therapy for oral cancer. In the face of this real time situation, there have been some successful attempts at targeted therapy for OSCC cells and we believe they might elicit favorable responses against TAMs as well. Demanding our immediate attention, this review intends to provide a glimpse of the prevailing anti-TAM treatment strategies, which present great prospect for an uncharted territory like OSCC.

Lineage-associated connexin 43 expression in bisphosphonate-exposed rat bones

Expression of signaling proteins in bone cells depends on their embryological mesoderm-derived (e.g. tibia) or cranial neural crest (CNC)-derived (e.g. jaw) origin. Connexin 43 (Cx43) is a gap junction protein that plays an essential role in the mode of action of bisphosphonates (BP). This study aimed to investigate Cx43 expression and the influence of BP application on mesoderm- and CNC-derived bone. Using a rat model, molar extraction and tibia osteotomy with (Group 4) or without (Group 3) previous BP application was performed. Untreated (Group 1) and animals selectively treated with BPs (Group 2) served as controls. Cx43 expression was immunohistochemically determined 12 and 16 weeks postoperatively via a labeling index. Cx43 expression in CNC-derived bone was significantly higher compared with mesodermal bone. BP application decreased Cx43 expression; however, detected expression levels were still higher in jawbone (Group 2 tibia vs jaw: 5.83 ± 5.06 vs 23.52 ± 6.42; p = 0.007). During bone healing after surgical intervention (Group 3) there were no expression differences between tibia and jawbone. BP treatment prior to surgery resulted in significantly lower Cx43 expression in CNC-derived compared with tibia bone (Group 4 tibia vs jaw: 56.84 ± 15.57 vs 16.40 ± 5.66; p < 0.01). Increased Cx43 expression in jaw compared with tibia bone is in line with their embryological origins. A significant Cx43 suppression in jawbone after BP application and surgery might contribute to the selectively altered osseous turnover and development of MRONJ in CNC-derived bone.

Importance of the PD-1/PD-L1 Axis for Malignant Transformation and Risk Assessment of Oral Leukoplakia

Background: The programmed cell death ligand 1/programmed cell death receptor 1 (PD-L1/PD-1) Immune Checkpoint is an important modulator of the immune response. Overexpression of the receptor and its ligands is involved in immunosuppression and the failure of an immune response against tumor cells. PD-1/PD-L1 overexpression in oral squamous cell carcinoma (OSCC) compared to healthy oral mucosa (NOM) has already been demonstrated. However, little is known about its expression in oral precancerous lesions like oral leukoplakia (OLP). The aim of the study was to investigate whether an increased expression of PD-1/PD-L1 already exists in OLP and whether it is associated with malignant transformation. Material and Methods: PD-1 and PD-L1 expression was immunohistologically analyzed separately in the epithelium (E) and the subepithelium (S) of OLP that had undergone malignant transformation within 5 years (T-OLP), in OLP without malignant transformation (N-OLP), in corresponding OSCC and in NOM. Additionally, RT-qPCR analysis for PD-L1 expression was done in the entire tissues. Additionally, the association between overexpression and malignant transformation, dysplasia and inflammation were examined. Results: Compared to N-OLP, there were increased levels of PD-1 protein in the epithelial and subepithelial layers of T-OLP (p_E = 0.001; p_S = 0.005). There was no significant difference in PD-L1 mRNA expression between T-OLP and N-OLP (p = 0.128), but the fold-change increase between these groups was significant (Relative Quantification (RQ) = 3.1). In contrast to N-OLP, the PD-L1 protein levels were significantly increased in the epithelial layers of T-OLP (p = 0.007), but not in its subepithelial layers (p = 0.25). Importantly, increased PD-L1 levels were significantly associated to malignant transformation within 5 years. Conclusion: Increased levels of PD-1 and PD-L1 are related to malignant transformation in OLP and may represent a promising prognostic indicator to determine the risk of malignant progression of OLP. Increased PD-L1 levels might establish an immunosuppressive microenvironment, which could favor immune escape and thereby contribute to malignant transformation. Hence, checkpoint inhibitors could counteract tumor development in OLP and may serve as efficient therapeutic strategy in patients with high-risk precancerous lesions.

Zoledronate Causes a Systemic Shift of Macrophage Polarization towards M1 In Vivo

BACKGROUND

Immunomodulatory properties of bisphosphonates (BP) are suggested to contribute to the development of medication-associated osteonecrosis of the jaw (MRONJ). Furthermore, bisphosphonate-derived immune modulation might contribute to the anti-metastatic effect observed in breast cancer patients. Macrophages are potential candidates for the mediation of immunomodulatory effects of bisphosphonates. The study aimed to investigate the influence of bisphosphonates alone and in combination with surgical trauma on systemic macrophage polarization (M1 vs. M2) using an in vivo rat model.

METHODS

A total of 120 animals were divided into four groups. Groups 2 and 4 were treated with 8 × 40 μg/kg body weight of the BP Zoledronate i.p. (week 0-7). Groups 3 and 4 were exposed to surgical trauma (week 8, tooth extraction + tibia fracture), whereas in Group 1 neither medication nor surgical trauma was applied. After 8, 10, 12 and 16 weeks, skin, lung and spleen were immunohistochemically examined for macrophage polarization via expression analysis of CD68, CD163 and iNOS using a tissue microarray (TMA).

RESULTS

A significant shift of macrophage polarization towards M1 was observed in skin, spleen and lung tissue of animals, with and without surgical trauma, treated with BP when compared to those without BP application. Surgical trauma did not cause a significant increase towards M1 polarization.

CONCLUSIONS

BP application leads to a systemic pro-inflammatory situation in vivo, independent of surgical trauma, as evidenced by the shift in macrophage polarization towards M1 in various somatic tissues. This provides a possible explanation for the clinically observed anti-tumor effect of bisphosphonates and might also contribute to pathogenesis of MRONJ.

PD1 expression and correlation with its ligands in oral cancer specimens and peripheral blood

OBJECTIVES

This study analyzed the expression of the PD1 receptor in tumor tissue and peripheral blood of oral squamous cell carcinoma (OSCC) patients, and correlated it with the PD1 ligands PD-L1 and PD-L2. The currently low response rates of checkpoint inhibitor treatment in OSCC could be increased by a better understanding of immune checkpoint biology. Despite evidence in the literature for upregulation of PD1 checkpoint ligands in OSCC tissue, there has been no correlation analysis of the PD1 receptor with its ligands in tissue specimens and peripheral blood of OSCC patients.

MATERIALS AND METHODS

An RT-qPCR analysis of PD1 mRNA expression was performed in oral cancer specimens, healthy mucosa, and corresponding blood samples. A cut-off point (COP) was determined and a chi-square (χ²) test was carried out. PD1 expression was correlated with previously reported PD-L1 and PD-L2 expression values using the Spearman test.

RESULTS

Tissue and blood specimens of 48 OSCC patients and 26 healthy individuals were analyzed. PD1 expression in OSCC specimens was significantly increased (p = 0.006) compared with healthy oral mucosa. PD1 overexpression in tissue samples showed a significant association with the presence of malignancy (p = 0.006). PD1 expression in tissue samples showed a significant positive correlation (p < 0.001) with the ligands PD-L1 and PD-L2. In contrast, there was no correlation between PD1 and its ligands in blood samples. However, there was a significant positive correlation (p < 0.001) between the ligands PD-L1 and PD-L2, both in tissue and blood samples.

CONCLUSIONS

Increased PD1 expression might be a manifestation of T-cell exhaustion in OSCC specimens, leading to immune tolerance. PD-L1/PD-L2-PD1 interaction may be a major mediator of local immunosuppression in OSCC, requiring advanced multimodal treatment protocols.

Preoperative oral immunonutrition in gastrointestinal surgical patients: How the tumour microenvironment can be modified

BACKGROUND & AIMS

This study is focused on the impact of enteral immunonutrition on the cell-mediated immune response in the microenvironment of gastric and colorectal cancers.

METHODS

This is a prospective pilot study approved by the local Ethics Committee. The immunophenotypic structure of the immune cells before (on the biopsy) and after (on the surgical sample) the administration of the immunonutrition in 16 patients is compared with 8 patients receiving regular diet. The samples of non-tumour tissue from sleeve-gastrectomy are used as non-neoplastic control. Antibodies were tested: CD4, CD8, PD-1, FOX-P3, CD68, CD163, CD80, CD21, CD56, PD-L1. We applied already well-known scoring systems for the evaluation of the immunohistochemistry and compared our data in the different groups by statistical analysis.

RESULTS

In treated patients, we detected a modulation of the immune response with higher number of cytotoxic and helper T-lymphocytes in the tumour microenvironment of the surgical specimens compared to the pre-operative biopsy, and a lower number of lymphocytes presenting an exhausted (i.e. double positive CD8 and PD-1 lymphocytes) and regulatory (i.e. double positive CD4 and FOX-P3 lymphocytes) phenotype. Moreover we observed the M1 polarization with a lower number of CD163 positive macrophages and the inhibition of the PD-1/PD-L1 pathway in treated patients.

CONCLUSIONS

The immunonutrition impacts on the tumoral microenvironment of gastric and colorectal cancer activating the inflammatory pathway, in terms of humoral and cellular response.

Macrophages in Oral Carcinomas: Relationship with Cancer Stem Cell Markers and PD-L1 Expression

Tumor-associated macrophages (TAMs) can be polarized into antitumoral M1 and protumoral and immunosuppressive M2 macrophages. This study investigated the clinical relevance of TAM infiltration in oral squamous cell carcinoma (OSCC), evaluating CD68 (M1 and M2 macrophage marker) and CD163 expression (M2 macrophage marker) in the tumor nests and surrounding stroma. Immunohistochemical analysis of both stromal/tumoral CD68⁺ and CD163⁺ TAMs was performed in paraffin-embedded tissue specimens from 125 OSCC patients, and correlated with clinical data. Potential relationships with the expression of cancer stem cell (CSC) markers and PD-L1 in the tumors were also assessed. Stromal CD163⁺ infiltration was significantly associated with the tumor location in the tongue, and stromal and tumoral CD68⁺ and CD163⁺-infiltrating TAMs were more abundant in nonsmokers and non-alcohol-drinkers. Strikingly, this study uncovers an inverse relationship between CD68⁺ and CD163⁺ TAMs and CSC marker expression (NANOG and SOX2) in OSCC. High infiltration of CD163⁺ TAMs in both tumor and stroma was strongly and significantly correlated with the absence of NANOG expression. Moreover, infiltration of both CD68⁺ and CD163⁺ TAMs was also significantly associated with high tumor expression of PD-L1. Our results suggest that there is a link between TAM infiltration and immune escape in OSCC.

Craniofacial Osteosarcoma-Pilot Study on the Expression of Osteobiologic Characteristics and Hypothesis on Metastasis

Background: Craniofacial osteosarcomas (COS) and extracranial osteosarcomas (EOS) show distinct clinical differences. COS show a remarkably lower incidence of metastases and a better survival. However, in contrast to EOS, they show a poor response to neoadjuvant chemotherapy. Tumor-associated macrophages and their polarization as well as developmental biological signaling pathways are possible candidates for explaining the clinical differences between COS and EOS. The aim of the study was to analyze differential expression of macrophage markers and important regulators of these pathways.

Methods: Twenty osteosarcoma cases (10 COS and 10 EOS) were immunohistochemically stained to assess CD68, CD11c, CD163, MRC1, Gli1, and Gli2 expression. Statistical differences between COS and EOS were tested using the Mann–Whitney U test. Additionally, the paper describes an example of multidisciplinary treatment of a patient suffering from COS and discusses the surgical challenges in treatment and rehabilitation of COS.

Results: COS showed a significantly (p < 0.05) increased infiltration of CD11c-positive M1 macrophages and a shift toward M1 polarization compared to EOS. Additionally, COS revealed a significantly (p < 0.05) lower Gli1 expression than EOS.

Conclusion: The reduced Gli1 expression in COS can be interpreted as reduced activation of the Hedgehog (Hh) signaling pathway. The increased M1 polarization and reduced Hh activation in COS could explain the low incidence of metastases in these osteosarcomas.

Characterization of the immune microenvironment of diffuse intrinsic pontine glioma: implications for development of immunotherapy

Background

Diffuse intrinsic pontine glioma (DIPG) is a uniformly fatal CNS tumor diagnosed in 300 American children per year. Radiation is the only effective treatment and extends overall survival to a median of 11 months. Due to its location in the brainstem, DIPG cannot be surgically resected. Immunotherapy has the ability to target tumor cells specifically; however, little is known about the tumor microenvironment in DIPGs. We sought to characterize infiltrating immune cells and immunosuppressive factor expression in pediatric low- and high-grade gliomas and DIPG.

Methods

Tumor microarrays were stained for infiltrating immune cells. RNA was isolated from snap-frozen tumor tissue and Nanostring analysis performed. DIPG and glioblastoma cells were co-cultured with healthy donor macrophages, T cells, or natural killer (NK) cells, and flow cytometry and cytotoxicity assays performed to characterize the phenotype and function, respectively, of the immune cells.

Results

DIPG tumors do not have increased macrophage or T-cell infiltration relative to nontumor control, nor do they overexpress immunosuppressive factors such as programmed death ligand 1 and/or transforming growth factor β1. H3.3-K27M DIPG cells do not repolarize macrophages, but are not effectively targeted by activated allogeneic T cells. NK cells lysed all DIPG cultures.

Conclusions

DIPG tumors have neither a highly immunosuppressive nor inflammatory microenvironment. Therefore, major considerations for the development of immunotherapy will be the recruitment, activation, and retention of tumor-specific effector immune cells.

Dihydroartemisinin Prevents Progression and Metastasis of Head and Neck Squamous Cell Carcinoma by Inhibiting Polarization of Macrophages in Tumor Microenvironment

Background

Polarized M2 macrophages are an important type of tumor-associated macrophage (TAM), with roles in the growth, invasion, and migration of cancer cells in the tumor microenvironment. Dihydroartemisinin (DHA), a traditional Chinese medicine extract, has been shown to inhibit the progression and metastasis of head and neck squamous cell carcinoma (HNSCC); however, the effect of DHA on cancer prevention, and the associated mechanism, has not been investigated in the tumor microenvironment.

Materials and Methods

First, human Thp-1 monocytes were induced and differentiated into M2 macrophages using phorbol 12-myristate 13-acetate (PMA), interleukin-6 (IL-6), and interleukin-4 (IL-4). Induction success was confirmed by cell morphology evaluation, flow cytometry, and quantitative real-time polymerase chain reaction (qRT-PCR). Then, DHA was applied to interfere with M2 macrophage polarization, and conditioned medium (CM), including conditioned medium from M2 macrophages (M2-CM) and conditioned medium from M2 macrophages with DHA (M2-DHA-CM), was obtained. CM was applied to Fadu or Cal-27 cells, and its effects on cancer invasion, migration, and angiogenesis were evaluated using transwell, wound-healing, and tube formation assays, respectively. Finally, Western blotting was used to evaluate the relationship between signal transducer and activator of transcription 3 (STAT3) signaling pathway activation and M2 macrophage polarization.

Results

Human Thp-1 monocytes were successfully polarized into M2-like TAMs using PMA, IL-6, and IL-4. We found that M2-like TAMs promoted the invasion, migration, and angiogenesis of HNSCC cells; however, DHA significantly inhibited IL-4/IL-6-induced M2 macrophage polarization. Additionally, as DHA induced a decrease in the number of M2-like TAMs, M2-DHA-CM inhibited the induction of invasion, migration, and angiogenesis of Fadu and Cal-27 cells. Finally, DHA inhibited M2 macrophage polarization by blocking STAT3 pathway activation in macrophages.

Conclusion

DHA inhibits the invasion, migration, and angiogenesis of HNSCC by preventing M2 macrophage polarization via blocking STAT3 phosphorylation.

Malignant transformation of oral leukoplakia is associated with macrophage polarization

Background

Most oral squamous cell carcinomas (OSCC) occur on the basis of oral leukoplakias (OLP). The histologic degree of dysplasia is insufficient for the prediction of OLP malignant transformation. Immunologic parameters are gaining importance for prognostic assessment and therapy of cancer. M2 polarized macrophages were shown to be associated with OSCC progression and inferior prognosis. The current study aims to answer the question if OLP with malignant transformation into OSCC within 5 years differ from OLP without transformation regarding macrophage infiltration and polarization.

Methods

201 specimens (50 transforming OLP, 53 non-transforming OLP, 49 corresponding OSCC and 49 healthy oral mucosa controls) were processed for immunohistochemistry. Samples were stained for CD68, CD163 and CD11c expression, completely digitalized and computer-assisted cell counting was performed. Epithelial and subepithelial compartments were differentially assessed. Groups were statistically compared using the Mann–Whitney U-test. A cut-off point for the discrimination of transforming and non-transforming OLP was determined and the association between macrophage infiltration and malignant transformation was calculated using the Chi-square test (χ² test).

Results

Macrophage infiltration and M2 polarization in OLP with malignant transformation within 5 years was significantly increased compared to OLP without malignant transformation (p < 0.05). OSCC samples showed the highest macrophage infiltration and strongest M2 polarization (p < 0.05). Additionally, transforming OLP revealed a significant shift of macrophage infiltration towards the epithelial compartment (p < 0.05). χ² test revealed a significant association of increased macrophage infiltration with malignant transformation (p < 0.05).

Conclusion

Immunological changes precede malignant transformation of OLP. Increased macrophage infiltration and M2 polarization was associated with the development of oral cancer in OLP. Macrophage infiltration could serve as predictive marker for malignant transformation.

TLR2 deficiency enhances susceptibility to oral carcinogenesis by promoting an inflammatory environment

Inflammation is closely related to oral squamous cell carcinoma (OSCC). However, its mechanism is still obscure. Toll-like receptor 2 (TLR2) plays an important role in oral chronic inflammatory diseases, but the role of TLR2 in OSCC is unclear. Here, we investigated the expression of TLR2 expression in OSCCs and examined the potential role of TLR2 in OSCC through its association with clinicopathological features and patient outcome. We used 4-nitroquinoline 1-oxide (4-NQO) to induce a tongue cancer model in TLR2-/- and wild type (WT) mice. Histological and clinical results both indicated that TLR2 played a protective role in oral tumorigenesis. The results of a cytometric bead array (CBA) indicated that TLR2 deficiency resulted in Th1 and Th2 cytokine abnormalities, especially Th2 abnormalities. Immunohistochemistry also showed that TLR2 deficiency increases the number of tongue-infiltrating M2 macrophages. Overall, our results demonstrated that TLR2 plays an important role in the prevention of oral tumorigenesis and affects the levels of Th2 cytokines and tongue-infiltrating M2 macrophages; therefore, it may be used to prevent the development of oral cancer.

Differences in Inflammation and Bone Resorption between Apical Granulomas, Radicular Cysts, and Dentigerous Cysts

INTRODUCTION

Dental cysts can be of inflammatory (radicular cysts) or noninflammatory (dentigerous cysts) origin. Apical periodontitis is a necrosis of the pulp and infection of the root canal causing the development of apical granulomas or radicular cysts. The immunology of granuloma and cyst formation is important because modern root filling materials are immunologically active and can contribute to the resolution of apical granulomas. In contrast, radicular cysts often require apicectomy. A better understanding of the pathophysiology of inflammation and bone resorption in apical periodontitis could be the basis for developing new root filling materials with superior immunomodulatory properties.

METHODS

Forty-one apical granulomas, 23 radicular cysts, and 23 dentigerous cysts were analyzed in this study. A tissue microarray of the 87 consecutive specimens was created, and human leukocyte antigen-DR isotype (HLA-DR)-, CD83-, receptor activator of nuclear factor kappa B ligand-, macrophage colony-stimulating factor (MCSF)-, galectin-3 (Gal3)-, CD4-, and CD8-positive cells were detected by immunohistochemistry. Tissue microarrays were digitized, and the expression of markers was quantitatively assessed.

RESULTS

HLA-DR, CD83, MCSF, and Gal3 expression was significantly (P < .05) higher in radicular cysts compared with apical granulomas. HLA-DR, CD83, MCSF, receptor activator of nuclear factor kappa B ligand, and Gal3 expression in dentigerous cysts was significantly (P < .05) lower than in both periapical lesions (apical granulomas and radicular cysts). CD4 and CD8 infiltration was not statistically different between apical granulomas and radicular cysts. Dentigerous cysts showed a significantly (P < .05) lower T-cell infiltration than apical periodontitis. The CD4/CD8 ratio was not significantly different between the analyzed groups.

CONCLUSIONS

The development of radicular cysts in apical periodontitis is associated with an increased expression of myeloid inflammatory markers and bone resorption parameters. Antigen-presenting cells and myeloid cells might be more relevant for the pathogenesis of apical periodontitis than T cells. Increased inflammation might promote the formation of radicular cysts and more pronounced bone resorption.

Prognostic Significance of Tumor-Associated Macrophage Content in Head and Neck Squamous Cell Carcinoma: A Meta-Analysis

Background: Head and neck squamous cell carcinoma (HNSCC) exists within a microenvironment rich in immune cells. Macrophages are particularly abundant in and around tumor tissue, and have been implicated in the growth, malignancy, and persistence of HNSCC (1). However, current literature reports variable degrees of association between the density of tumor-associated macrophages (TAMs) and clinicopathologic markers of disease (2, 3). These inconsistent findings may be a result of differences in approach to TAM detection. Authors have measured total TAMs in tumor tissue, while others have stained tumor samples for individual subtypes of TAMs, which include pro-inflammatory (M1-like) and immunosuppressive (M2-like). Our aim is to more clearly define the prognostic significance of the phenotypes of tumor-associated macrophages in HNSCC. Methods: We conducted a meta-analysis of the existing publications investigating the relationship between TAMs (total and M2-like subtype) and T stage, nodal involvement, vascular invasion, lymphatic invasion, and tumor differentiation (Figure 1). A total of 12 studies were included. Forest plots and risk ratios were generated to report overall effect. Results: Higher density of both total and M2-like subtype of TAMs in the tumor microenvironment is associated with advanced T stage, increased rates of nodal positivity, presence of vascular invasion, and presence of lymphatic invasion (p < 0.0001; Figures 2-9). There is no significant association between TAM density, either total or M2-like subtype, and tumor differentiation (Figures 10, 11). Conclusions: Increased density of TAMs, including those of the M2-like phenotype, correlate with poor clinicopathologic markers in HNSCC. Our findings warrant additional investigation into the subpopulations of TAMs, the mechanisms behind their recruitment and differentiation, and the associated influence of each phenotype on tumor growth and invasion. A greater understanding of TAM dynamics in HNSCC is critical for directing further research and employing TAM-targeted adjunct therapies.

Putative Role of Circulating Human Papillomavirus DNA in the Development of Primary Squamous Cell Carcinoma of the Middle Rectum: A Case Report

Here we present the case of a patient affected by rectal squamous cell carcinoma in which we demonstrated the presence of Human Papillomavirus (HPV) by a variety of techniques. Collectively, the virus was detected not only in the tumor but also in some regional lymph nodes and in non-neoplastic mucosa of the upper tract of large bowel. By contrast, it was not identifiable in its common sites of entry, namely oral and ano-genital region. We also found HPV DNA in the plasma-derived exosome. Next, by in vitro studies, we confirmed the capability of HPV DNA-positive exosomes, isolated from the supernatant of a HPV DNA positive cell line (CaSki), to transfer its DNA to human colon cancer and normal cell lines. In the stroma nearby the tumor mass we were able to demonstrate the presence of virus DNA in the stromal compartment, supporting its potential to be transferred from epithelial cells to the stromal ones. Thus, this case report favors the notion that human papillomavirus DNA can be vehiculated by exosomes in the blood of neoplastic patients and that it can be transferred, at least in vitro, to normal and neoplastic cells. Furthermore, we showed the presence of viral DNA and RNA in pluripotent stem cells of non-tumor tissue, suggesting that after viral integration (as demonstrated by p16 and RNA in situ hybridization positivity), stem cells might have been activated into cancer stem cells inducing neoplastic transformation of normal tissue through the inactivation of p53, p21, and Rb. It is conceivable that the virus has elicited its oncogenic effect in this specific site and not elsewhere, despite its wide anatomical distribution in the patient, for a local condition of immune suppression, as demonstrated by the increase of T-regulatory (CD4/CD25/FOXP3 positive) and T-exhausted (CD8/PD-1positive) lymphocytes and the M2 polarization (high CD163/CD68 ratio) of macrophages in the neoplastic microenvironment. It is noteworthy that our findings depicted a static picture of a long-lasting dynamic process that might evolve in the development of tumors in other anatomical sites.

Myeloid cell IRF4 signaling protects neonatal brains from hypoxic ischemic encephalopathy

Interferon regulatory factor 4 (IRF4), a transcription factor recognized as a key regulator of lymphoid and myeloid cell differentiation, has recently been recognized as a critical mediator of macrophage activation. Previously we have reported that IRF4 signaling is closely correlated with anti-inflammatory polarization of microglia in adult mice after stroke. However, IRF4's role in the inflammatory response in the immature brain is unknown. Using a model of neonatal hypoxic ischemic encephalopathy (HIE) we investigated the regulatory action of IRF4 signaling in the activation of microglia and monocytes after HIE. IRF4 myeloid cell conditional knockout (CKO) postnatal day 10 (P10) male pups were subjected to a 60-min hypoxic-ischemic insult by the Rice-Vanucci model (RVM). IRF4 gene floxed mice (IRF4^fl/fl) were used as controls. Brain atrophy and behavioral deficits were measured 7 days after HIE. Flow cytometry (FC) was performed to examine central (microglial activation) and peripheral immune cell responses by both cell membrane and intracellular marker staining. Serum levels of cytokines were determined by ELISA. The results showed that IRF4 CKO pups had increased tissue loss and worse behavioral deficits than IRF4^fl/fl mice seven days after HIE. FC demonstrated significantly more infiltration of monocytes and neutrophils in the ischemic brains of IRF4 CKO vs IRF4^fl/fl pups. IRF4 CKO ischemic microglia were more pro-inflammatory as evidenced by higher expression of the pro-inflammatory marker CD68, and increased intracellular TNFα and IL-1β levels compared to controls. In addition, IRF4 deletion from myeloid cells resulted in increased levels of circulating pro-inflammatory cytokines and higher endothelial MMP9 expression after HIE. These data indicate that IRF4 signaling in myeloid cells plays a regulatory role in neuroinflammation and that deletion of myeloid IRF4 is detrimental to HIE injury, suggesting that IRF4 could serve as a potential therapeutic target for neonatal ischemic brain injury.

Galectin 3 expression in regional lymph nodes and lymph node metastases of oral squamous cell carcinomas

BACKGROUND

Neck dissection is standard in surgical management of oral squamous cell carcinomas (oscc). However, the immunologic link between primary tumor and lymph nodes is insufficiently understood. Galectin 3 (Gal3) promotes M2 polarization of macrophages and contributes to immunosuppression. The current study analyzes the association between Gal3 expression in regional lymph nodes of oscc with histomorphologic parameters (T-, N-, L- Pn-stage, grading) of the primary tumor. Additionally, Gal3 expression is correlated with markers of macrophage polarization (M1 vs. M2).

METHODS

Preoperative diagnostic biopsies (n = 26), tumor resection specimens (n = 34), tumor-free lymph nodes (n = 28) and lymph node metastases (n = 10) of T1/T2 oscc patients were immunohistochemically analyzed for Gal3 and macrophage marker (CD68, CD11c, CD163 and MRC1) expression. The number of positive cells and the expression ratios were quantitatively assessed.

RESULTS

High Gal3 expression in tumor-free regional lymph nodes was significantly (p < 0.05) associated with increased tumor size. The epithelial compartment of lymph node metastases showed a significantly (p < 0.05) increased Gal3 expression compared to biopsies and tumor resection specimens. Cell density of M2 macrophages was significantly (p < 0.05) and positively correlated with the number of Gal3 expressing cells in lymph nodes and tumor specimens.

CONCLUSION

Gal3 expression in regional lymph nodes might be associated with oscc progression. The increased Gal3 expression in regional lymph nodes of larger tumors underlines the need of immunomodulatory treatment concepts in early-stage oscc. Blocking of Gal3 might be a therapeutic option in oral cancer.

Immunomodulation by ionizing radiation-impact for design of radio-immunotherapies and for treatment of inflammatory diseases

Ionizing radiation is often regarded as an element of danger. But, danger responses on the cellular and molecular level are often beneficial with regard to the induction of anti-tumor immunity and for amelioration of inflammation. We outline how in dependence of radiation dose and fraction, radiation itself-and especially in combination with immune modulators-impacts on the innate and adaptive immune system. Focus is set on radiation-induced changes of the tumor cell phenotype and the cellular microenvironment including immunogenic cancer cell death. Mechanisms how anti-tumor immune responses are triggered by radiotherapy in combination with hyperthermia, inhibition of apoptosis, the adjuvant AnnexinA5, or vaccination with high hydrostatic pressure-killed autologous tumor cells are discussed. Building on this, feasible multimodal radio-immunotherapy concepts are reviewed including overcoming immune suppression by immune checkpoint inhibitors and by targeting TGF-β. Since radiation-induced tissue damage, inflammation, and anti-tumor immune responses are interconnected, the impact of lower doses of radiation on amelioration of inflammation is outlined. Closely meshed immune monitoring concepts based on the liquid biopsy blood are suggested for prognosis and prediction of cancer and non-cancer inflammatory diseases. Finally, challenges and visions for the design of cancer radio-immunotherapies and for treatment of benign inflammatory diseases are given.

Potential impact of invasive surgical procedures on primary tumor growth and metastasis

Surgical procedures such as tumor resection and biopsy are still the gold standard for diagnosis and (determination of) treatment of solid tumors, and are prognostically beneficial for patients. However, growing evidence suggests that even a minor surgical trauma can influence several (patho) physiological processes that might promote postoperative metastatic spread and tumor recurrence. Local effects include tumor seeding and a wound healing response that can promote tumor cell migration, proliferation, differentiation, extracellular matrix remodeling, angiogenesis and extravasation. In addition, local and systemic immunosuppression impairs antitumor immunity and contributes to tumor cell survival. Surgical manipulation of the tumor can result in cancer cell release into the circulation, thus increasing the chance of tumor cell dissemination. To prevent these undesired effects of surgical interventions, therapeutic strategies targeting immune response exacerbation or alteration have been proposed. This review summarizes the current literature regarding these local, systemic and secondary site effects of surgical interventions on tumor progression and dissemination, and discusses studies that aimed to identify potential therapeutic approaches to prevent these effects in order to further increase the clinical benefit from surgical procedures.

Merkel cell carcinoma expresses the immunoregulatory ligand CD200 and induces immunosuppressive macrophages and regulatory T cells

Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer that responds to PD-1/PD-L1 immune checkpoint inhibitors. CD200 is another checkpoint modulator whose receptor is found on tumor-promoting myeloid cells, including M2 macrophages. We found high CD200 mRNA expression in MCC tumors, and CD200 immunostaining was demonstrated on 95.5% of MCC tumors. CD200R-expressing myeloid cells were present in the MCC tumor microenvironment. MCC-associated macrophages had a higher average CD163:CD68 staining ratio (2.67) than controls (1.13), indicating an immunosuppressive M2 phenotype. Accordingly, MCC tumors contained increased densities of FOXP3⁺ regulatory T-cells. Intravenous administration of blocking anti-CD200 antibody to MCC xenograft mice revealed specific targeting of drug to tumor. In conclusion, MCC are highly CD200 positive and associated with immunosuppressive M2 macrophages and regulatory T-cells. As anti-CD200 antibody effectively targets CD200 on MCC tumor cells in vivo, this treatment may provide a novel immunotherapy for MCC independent of PD-1/PD-L1 blockade.

Galectin 3 expression in primary oral squamous cell carcinomas

Background

Immunologic factors can promote the progression of oral squamous cell carcinomas (oscc). The phylogenetic highly conserved protein Galectin 3 (Gal3) contributes to cell differentiation and immune homeostasis. There is evidence that Gal3 is involved in the progression of oscc and influences the regulation of macrophage polarization. Macrophage polarization (M1 vs. M2) in solid malignancies like oscc contributes to tumor immune-escape. However, the relationship between macrophage polarization and Gal3 expression in oscc is not yet understood. The current study analyzes the association between histomorphologic parameters (T-, N-, L- Pn-status, grading) and Gal3 expression resp. the ratio between Gal3 expressing cells and CD68 positive macrophages in oscc specimens.

Methods

Preoperative diagnostic biopsies (n = 26) and tumor resection specimens (n = 34) of T1/T2 oscc patients were immunohistochemically analyzed for Gal3 and CD68 expression. The number of Gal3 expressing cells and the ratio between CD68 and Gal3 expressing cells was quantitatively assessed.

Results

In biopsy and tumor resection specimens, the number of Gal3 positive cells as well as the Gal3/CD68 ratio were significantly (p < 0.05) higher in T2 oscc compared to T1 cases. In biopsy specimens, a significantly (p < 0.05) increased Gal3 expression and Gal3/CD68 ratio was associated with the progression marker lymph vessel infiltration (L1). Tumor resection specimens of cases with lymph node metastases (N+) had a significantly (p < 0.05) increased Gal3 expression. Additionally, a high Gal3/CD68 ratio correlated significantly (p < 0.05) with higher grading (G3) in tumor resection specimens.

Conclusion

High Gal3 expression in oscc is associated with tumor size (T-status) and parameters of malignancy (N-, L-status, grading). Gal3 might contribute to M2 macrophage mediated local immune tolerance. Gal3 expression shows association with prognosis in oscc and represent a potential therapeutic target.

Core-needle biopsy of breast cancer is associated with a higher rate of distant metastases 5 to 15 years after diagnosis than FNA biopsy

BACKGROUND

The literature offers discordant results regarding whether diagnostic biopsy is associated with the dissemination of cancer cells, resulting in local and/or distant metastasis. The long-term outcomes of patients with breast cancer were compared between those who were diagnosed using either fine-needle aspiration biopsy (FNAB) or core-needle biopsy (CNB) during 2 decades: the 1970s and 1990s.

METHODS

In the 1970s, the only diagnostic needle biopsy method used for breast cancer in Sweden was FNAB. CNB was introduced 1989 and became established in Stockholm Gotland County in the early 1990s. The authors compared the clinical outcomes of patients diagnosed using FNAB from 1971 to 1976 (n = 354) versus those of patients diagnosed using CNB from 1991 to 1995 (n = 1729). Adjusting for differences in various treatment modalities, mammography screening, tumor size, DNA ploidy, and patient age between the 2 decades, 2 strictly matched samples representing FNAB (n = 181) and CNB (n = 203) were selected for a 15-year follow-up study.

RESULTS

In a comparison of the rates of distant metastasis in the strictly matched patient groups from the FNAB and CNB cohorts, significantly higher rates of late-appearing (5-15 years after diagnosis) distant metastasis were observed among the patients who were diagnosed on CNB compared with those who were diagnosed on FNAB. No significant difference in local metastasis was observed between the 2 groups.

CONCLUSIONS

At 5 to 15 years after diagnosis of the primary tumor, CNB-diagnosed patients had significantly higher rates of distant metastases than FNAB-diagnosed patients. Cancer Cytopathol 2017;125:748-56. © 2017 American Cancer Society.

Cancer Cell Death-Inducing Radiotherapy: Impact on Local Tumour Control, Tumour Cell Proliferation and Induction of Systemic Anti-tumour Immunity

Radiotherapy (RT) predominantly is aimed to induce DNA damage in tumour cells that results in reduction of their clonogenicity and finally in tumour cell death. Adaptation of RT with higher single doses has become necessary and led to a more detailed view on what kind of tumour cell death is induced and which immunological consequences result from it. RT is capable of rendering tumour cells immunogenic by modifying the tumour cell phenotype and the microenvironment. Danger signals are released as well as the senescence-associated secretory phenotype. This results in maturation of dendritic cells and priming of cytotoxic T cells as well as in activation of natural killer cells. However, RT on the other hand can also result in immune suppressive events including apoptosis induction and foster tumour cell proliferation. That's why RT is nowadays increasingly combined with selected immunotherapies.

Fibrotic focus: An important parameter for accurate prediction of a high level of tumor-associated macrophage infiltration in invasive ductal carcinoma of the breast

Our group and others have previously reported that a fibrotic focus is a very useful histological factor for the accurate prediction of the outcome of patients with invasive ductal carcinoma of the breast. We classified 258 cases of invasive ductal carcinoma into those with and those without a fibrotic focus to investigate whether the presence of a fibrotic focus was significantly associated with the degree of tumor-associated macrophage (CD68, CD163 or CD204-positive) infiltration or whether the presence of tumor-associated macrophage infiltration heightened the malignant potential of invasive ductal carcinoma with a fibrotic focus. Multiple regression analyses demonstrated that a fibrotic focus was the only factor that was significantly associated with a high level of CD68-, CD163- or CD204-positive tumor-associated macrophage infiltration. The combined assessment of the presence or absence of a fibrotic focus and a high or a low level of CD204-positive tumor-associated macrophage infiltration clearly demonstrated that CD204-positive tumor-associated macrophage infiltration had a significant prognostic power only for patients with invasive ductal carcinoma with a fibrotic focus in multivariate analyses; CD204-positive tumor-associated macrophages might only exert a significant effect on tumor progression when a fibrotic focus is present within the invasive ductal carcinoma of the breast.

Kif4A mediate the accumulation and reeducation of THP-1 derived macrophages via regulation of CCL2-CCR2 expression in crosstalking with OSCC

Crosstalk between tumor infiltrating macrophages and tumor cells is thought to play an indispensable role in oral squamous cell carcinomas (OSCC) by induction and maintenance of tolerance microenvironment. High infiltration of M2 macrophages and increasing expression of Kinesin family member 4A (Kif4A) in primary OSCC have been proved to correlate with greater tumoral size and poor clinical outcome. However, linkage between Kif4A and infiltrating macrophages in tumorigenesis and progression remains unclear. In the present study, we show that, the interaction between THP-1derived macrophage and OSCC cell line Cal-27 may up-regulate the Kif4A expression in both of them. Additionally, elevated soluble CCL2 in medium and more expression of CCR2 on macrophage were observed during the crosstalk. SiRNA of Kif4A and neutralizing antibody of CCL2 were utilized to identify that; increasing Kif4A can promote the recruitment of macrophages towards Cal-27 and educate them to M2 polarized macrophages via regulating CCL2/CCR2. In combination, the results of the present study may provide interesting clues to understanding the Kif4A-CCL2/CCR2-macrophage axis as a novel therapeutic target to improve the clinical outcome of OSCC.

Macrophage polarization differs between apical granulomas, radicular cysts, and dentigerous cysts

OBJECTIVES

Apical periodontitis can appear clinically as apical granulomas or radicular cysts. There is evidence that immunologic factors are involved in the pathogenesis of both pathologies. In contrast to radicular cysts, the dentigerous cysts have a developmental origin. Macrophage polarization (M1 vs M2) is a main regulator of tissue homeostasis and differentiation. There are no studies comparing macrophage polarization in apical granulomas, radicular cysts, and dentigerous cysts.

MATERIALS AND METHODS

Forty-one apical granulomas, 23 radicular cysts, and 23 dentigerous cysts were analyzed in this study. A tissue microarray (TMA) of the 87 consecutive specimens was created, and CD68-, CD11c-, CD163-, and MRC1-positive macrophages were detected by immunohistochemical methods. TMAs were digitized, and the expression of macrophage markers was quantitatively assessed.

RESULTS

Radicular cysts are characterized by M1 polarization of macrophages while apical granulomas show a significantly higher degree of M2 polarization. Dentigerous cysts have a significantly lower M1 polarization than both analyzed periapical lesions (apical granulomas and radicular cysts) and accordingly, a significantly higher M2 polarization than radicular cysts. Macrophage cell density in dentigerous cysts is significantly lower than in the periapical lesions.

CONCLUSIONS

The development of apical periodontitis towards apical granulomas or radicular cysts might be directed by macrophage polarization. Radicular cyst formation is associated with an increased M1 polarization of infiltrating macrophages. In contrast to radicular cysts, dentigerous cysts are characterized by a low macrophage infiltration and a high degree of M2 polarization, possibly reflecting their developmental rather than inflammatory origin.

CLINICAL RELEVANCE

As M1 polarization of macrophages is triggered by bacterial antigens, these results underline the need for sufficient bacterial clearance during endodontic treatment to prevent a possible M1 macrophage-derived stimulus for radicular cyst formation.

CD163+CD204+ tumor-associated macrophages contribute to T cell regulation via interleukin-10 and PD-L1 production in oral squamous cell carcinoma

Tumor-associated macrophages (TAMs) promote cancer cell proliferation, invasion, and metastasis by producing various mediators. Although preclinical studies demonstrated that TAMs preferentially express CD163 and CD204, the TAM subsets in oral squamous cell carcinoma (OSCC) remain unknown. In this study, we examined the expression and role of TAM subsets in OSCC. Forty-six patients with OSCC were analyzed for expression of TAMs in biopsy samples by immunohistochemistry. We examined TAM subsets and their production of immune suppressive molecules (IL-10 and PD-L1) in peripheral blood mononuclear cells from three OSCC patients by flow cytometry. CD163 was detected around the tumor or connective tissue, while CD204 was detected in/around the tumors. Flow cytometric analysis revealed that CD163+CD204+ TAMs strongly produced IL-10 and PD-L1 in comparison with CD163+CD204- and CD163-CD204+ TAMs. Furthermore, the number of activated CD3+ T cells after co-culture with CD163+CD204+ TAMs was significantly lower than that after co-culture with other TAM subsets. In clinical findings, the number of CD163+CD204+ TAMs was negatively correlated with that of CD25+ cells and 5-year progression-free survival. These results suggest that CD163+CD204+ TAMs possibly play a key role in the invasion and metastasis of OSCC by T-cell regulation via IL-10 and PD-L1 production.

Role of tumour-associated macrophages in oral squamous cells carcinoma progression: an update on current knowledge

BACKGROUND

Oral squamous cell carcinoma (OSCC) accounts over 90% of malignant neoplasms of the oral cavity. This pathological entity is associated to a high mortality rate that has remained unchanged over the past decades. Tumour-associated macrophages (TAMs) are believed to have potential involvement in OSCC progression. However, the molecular networks involved in communication between stroma and cancer cells have not yet been fully elucidated.

MAIN BODY

The role of M2 polarized cells in oral carcinogenesis is supported by a correlation between TAMs accumulation into OSCC stroma and poor clinical outcome. Signalling pathways such as the NF-κB and cytokines released in the tumour microenvironment promote a bidirectional cross-talk between M2 and OSCC cells. These interactions consequently result in an increased proliferation of malignant cells and enhances aggressiveness, thus reducing patients' survival time.

CONCLUSIONS

Here, we present a comprehensive review of the role of interleukin (IL)-1, IL-4, IL-6, IL-8, IL-10 and the receptor tyrosine kinase Axl in macrophage polarization to an M2 phenotype and OSCC progression. Understanding the molecular basis of oral carcinogenesis and metastatic spread of OSCC would promote the development of targeted treatment contributing to a more favourable prognosis.

Macrophage and osteoclast polarization in bisphosphonate associated necrosis and osteoradionecrosis

PURPOSE

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a complication of antiresorptive therapy with nitrogen-containing bisphosphonates (BP). With various suggestions as to pathogenesis, the etiology of BRONJ is not sufficiently understood. Osteoclasts and their precursors, that is, macrophages, are the main target cells of BP. BP can repolarize regeneration- and healing-associated M2 macrophages towards the tissue destructive M1-type. The current study aims to elucidate differences in macrophage and osteoclast polarization in BRONJ, osteoradionecrosis (ORN) and healthy control specimens.

MATERIALS AND METHODS

A total of 39 jaw bone samples (18 BRONJ, 8 ORN and 13 healthy controls) were processed for immunohistochemistry to detect CD68-, CD11c- and CD163-positive cells. Macrophages and osteoclasts were distinguished on the basis of morphological differences. Samples were digitized, and the macrophage and osteoclast cell counts were quantitatively analyzed.

RESULTS

In jaw bone affected by BRONJ, a significantly increased macrophage infiltration and M1 polarization of macrophages can be seen. The density of CD68-expressing osteoclasts is significantly increased in BRONJ specimens compared to ORN and to healthy controls.

CONCLUSIONS

A bisphosphonate-derived shift of macrophage polarization towards M1-polarized macrophages might impair bone tissue homeostasis and thus contribute to the pathogenesis of BRONJ. The observed increase in osteoclast density might be caused by BP-induced prolonged osteoclast survival.

Oral squamous cell carcinoma suppressed antitumor immunity through induction of PD-L1 expression on tumor-associated macrophages

Oral squamous cell carcinoma (OSCC) is the most common solid tumor in the oral cavity. Development and progression of OSCC is associated with the elevated presence of inhibitory M2 type tumor-associated macrophages (TAMs). However, the underlying mechanism leading to the enrichment of M2 TAMs and the pathway through which TAMs foster tumor progression are still unclear. In this study, we harvested TAMs and tumor cells from primary OSCC resections of stage II and stage III patients. We showed that compared to peritumoral macrophages, TAMs presented upregulated expression of PD-L1 and elevated capacity in inducing T cell apoptosis. The level of PD-L1 expression directly correlated with the level of T cell apoptosis. Interestingly, peripheral blood monocytes with low initial PD-L1 level had upregulated PD-L1 expression and acquired the ability to induce T cell apoptosis, after incubation with primary tumor cells from OSCC patients. The PD-L1 expression by monocytes depended on interleukin 10 (IL-10), since blockade of IL-10 in the tumor-monocyte coculture abrogated PD-L1 upregulation. IL-10 mRNA expression in tumor cells and monocytes also preceded PD-L1 mRNA expression in monocytes. Furthermore, the IL-10 concentration in the tumor microenvironment directly correlated with the PD-L1 level on TAMs. Together, these results suggest that OSCC could directly suppress antitumor T cell immunity through conditioning TAMs.

Relationship between tumor-associated macrophage subsets and CD47 expression in squamous cell carcinoma of the head and neck in the tumor microenvironment

Tumor-associated macrophages (TAM) have been classified into an immunostimulatory M1 subset against microbes and malignancies, and an immunoregulatory M2 subset that secretes immunosuppressive cytokines in order to repair tissues damaged by malignancies. The infiltration of M2 in the tumor microenvironment is known to facilitate immunosuppression and tumor-promoting properties. In the present study, we investigated the phagocytic potential of these macrophage subsets in oral squamous cell carcinoma (OSCC) in relation to the expression of CD47, the 'don't eat me' signal against macrophages. The macrophage subsets M1 (induced by GM-CSF and IFN-γ) and M2 (induced by M-CSF and IL-10) were derived from the CD14(+) cells of healthy donors. Phagocytosis of the CFSE-labeled CD47(+) cell line HSC-3 by M1/M2 was assessed using flow cytometry and suppressed by an anti-CD47 neutralizing antibody or CD47 siRNA. Furthermore, CD68(+) and CD163(+) macrophage subset counts infiltrating tumor tissue and the expression of CD47 on cancer cells were examined immunohistochemically in 74 cases of OSCC, and their relationships with clinicopathological parameters or prognoses were determined. The phagocytic potential of M1 was similar to that of M2 in vitro. Phagocytosis by M1 increased in a CD47-dependent manner by the neutralizing antibody and siRNA, but did not in M2. An immunohistochemical (IHC) analysis revealed that the expression of CD47 did not correlate with macrophage subsets in peritumoral tissue or with any clinicopathological parameters; however, the stronger expression of CD47 by cancer cells and larger number of total macrophages/M2 were independently related to shorter survivals. Our results suggest that the expression of CD47 by cancer cells is related to evasion from phagocytosis, particularly that by M1 in vitro. IHC results indicate that various mechanisms are involved in the engulfing potential of TAM subsets in vivo.

Prognostic value of polarized macrophages in patients with hepatocellular carcinoma after curative resection

As the most predominant tumour‐infiltrating immune cells, tumour‐associated macrophages (TAMs) are significant for fostering tumour growth, progression and metastasis. CD68‐positive TAMs display dissimilarly polarized programmes comprising CD11c‐positive pro‐inflammatory macrophages (M1) and CD206‐positive immunosuppressive macrophages (M2). The aim of this study is to determine the prognostic significance of diametrically polarized TAMs in hepatocellular carcinoma (HCC) and their application to risk stratification of patients according to their specific prognostic values. This study included 80 consecutive patients with HCC, and we evaluated diametrically polarized functional status of macrophages by immunohistochemical staining of CD68, CD11c and CD206. Prognostic values and clinicopathologic features were assessed in these patients. High versus low CD11c‐positive TAM density (P = 0.005) and low versus high CD206‐positive TAM density (P = 0.002) were associated with better overall survival, whereas CD68‐positive TAM density had no prognostic significance (low versus high, P = 0.065). Furthermore, the presence of these positive staining macrophages did not show any prognostic significance for recurrence‐free survival (all P > 0.05). Multivariate Cox regression analysis identified CD11c‐positive and CD206‐positive TAMs as an independent prognostic factor (P < 0.001, P = 0.031, respectively). Intratumoural infiltration of diametrically polarized TAMs, a novel identified independent prognostic factor for survival in patients with HCC, could be combined with the TNM stage and the Barcelona Clinic Liver Cancer stage to improve a risk stratification system.

Investigation of the interplay between plasma lipids and macrophage polarization in small oral squamous cell carcinomas with different outcome: A pilot study of 17 cases

INTRODUCTION

Growing evidence suggests a correlation of alternative polarization of macrophages (M2) with a bad outcome of oral cancer. Macrophage polarization plays a significant role in the progression of hyperlipidemia and atherosclerosis, being influenced from plasma cholesterol. On the other hand plasma lipids have been studied epidemiologically as risk factors in carcinogenesis. Goal of our pilot study was the investigation of a possible association of plasma lipids with tumor outcome through their potential influence on macrophage polarization.

MATERIALS AND METHODS

17 patients with small pN0 OSCC with different clinical outcome, treated operatively without postoperative R(C)T constituted our patient collective. Plasma lipids (total cholesterol and triglycerides) were studied in relation to macrophage polarization (determined through the expression of CD68, CD11c, CD163 and MRC1 antibodies) and tumor outcome.

RESULTS

Patients with pathological chronic course of either plasma cholesterol or triglycerides demonstrated an increased infiltration with alternatively polarized macrophages in their specimens. Patients with pathological chronic course of plasma cholesterol showed moreover a bad tumor outcome.

CONCLUSION

A role of plasma lipids in the tumor outcome via alternative macrophage polarization could be assumed. A larger prospective study is needed to confirm our preliminary results.

Systemic Inflammation in Cachexia - Is Tumor Cytokine Expression Profile the Culprit?

Cachexia affects about 80% of gastrointestinal cancer patients. This multifactorial syndrome resulting in involuntary and continuous weight loss is accompanied by systemic inflammation and immune cell infiltration in various tissues. Understanding the interactions among tumor, immune cells, and peripheral tissues could help attenuating systemic inflammation. Therefore, we investigated inflammation in the subcutaneous adipose tissue and in the tumor, in weight stable and cachectic cancer patients with same diagnosis, in order to establish correlations between tumor microenvironment and secretory pattern with adipose tissue and systemic inflammation. Infiltrating monocyte phenotypes of subcutaneous and tumor vascular-stromal fraction were identified by flow cytometry. Gene and protein expression of inflammatory and chemotactic factors was measured with qRT-PCR and Multiplex Magpix(®) system, respectively. Subcutaneous vascular-stromal fraction exhibited no differences in regard to macrophage subtypes, while in the tumor, the percentage of M2 macrophages was decreased in the cachectic patients, in comparison to weight-stable counterparts. CCL3, CCL4, and IL-1β expression was higher in the adipose tissue and tumor tissue in the cachectic group. In both tissues, chemotactic factors were positively correlated with IL-1β. Furthermore, positive correlations were found for the content of chemoattractants and cytokines in the tumor and adipose tissue. The results strongly suggest that the crosstalk between the tumor and peripheral tissues is more pronounced in cachectic patients, compared to weight-stable patients with the same tumor diagnosis.