Interactions between cancer-associated fibroblasts and T-cells: functional crosstalk with targeting and biomarker potential.

Cancer-associated fibroblasts (CAFs) are a heterogeneous cell population recognized as a key component of the tumour microenvironment (TME). Cancer-associated fibroblasts are known to play an important role in maintaining and remodelling the extracellular matrix (ECM) in the tumour stroma, supporting cancer progression and inhibiting the immune system's response against cancer cells. This review aims to summarize the immunomodulatory roles of CAFs, particularly focussing on their T-cell suppressive effects. Cancer-associated fibroblasts have several ways by which they can affect the tumour's immune microenvironment (TIME). For example, their interactions with macrophages and dendritic cells (DCs) create an immunosuppressive milieu that can indirectly affect T-cell anticancer immunity and enable immune evasion. In addition, a number of recent studies have confirmed CAF-mediated direct suppressive effects on T-cell anticancer capacity through ECM remodelling, promoting the expression of immune checkpoints, cytokine secretion and the release of extracellular vesicles. The consequential impact of CAFs on T-cell function is then reflected in affecting T-cell proliferation and apoptosis, migration and infiltration, differentiation and exhaustion. Emerging evidence highlights the existence of specific CAF subsets with distinct capabilities to modulate the immune landscape of TME in various cancers, suggesting the possibility of their exploitation as possible prognostic biomarkers and therapeutic targets.

Development of 42 marker panel for in-depth study of cancer associated fibroblast niches in breast cancer using imaging mass cytometry.

Imaging Mass Cytometry (IMC) is a novel, and formidable high multiplexing imaging method emerging as a promising tool for in-depth studying of tissue architecture and intercellular communications. Several studies have reported various IMC antibody panels mainly focused on studying the immunological landscape of the tumor microenvironment (TME). With this paper, we wanted to address cancer associated fibroblasts (CAFs), a component of the TME very often underrepresented and not emphasized enough in present IMC studies. Therefore, we focused on the development of a comprehensive IMC panel that can be used for a thorough description of the CAF composition of breast cancer TME and for an in-depth study of different CAF niches in relation to both immune and breast cancer cell communication. We established and validated a 42 marker panel using a variety of control tissues and rigorous quantification methods. The final panel contained 6 CAF-associated markers (aSMA, FAP, PDGFRa, PDGFRb, YAP1, pSMAD2). Breast cancer tissues (4 cases of luminal, 5 cases of triple negative breast cancer) and a modified CELESTA pipeline were used to demonstrate the utility of our IMC panel for detailed profiling of different CAF, immune and cancer cell phenotypes.

VEGF-C-expressing TAMs rewire the metastatic fate of breast cancer cells.

The expression of pro-lymphangiogenic VEGF-C in primary tumors is associated with sentinel lymph node metastasis in most solid cancer types. However, the impact of VEGF-C on distant organ metastasis remains unclear. Perivascular tumor-associated macrophages (TAMs) play a crucial role in guiding hematogenous spread of cancer cells by establishing metastatic pathways within the tumor microenvironment. This process supports breast cancer cell intravasation and metastatic dissemination. We show here that VEGF-C-expressing TAMs reduce the dissemination of mammary cancer cells to the lungs while concurrently increasing lymph node metastasis. These TAMs express podoplanin and interact with normalized tumor blood vessels expressing VEGFR3. Moreover, clinical data suggest inverse association between VEGF-C-expressing TAMs and breast cancer malignancy. Thus, our study elucidates the paradoxical role of VEGF-C-expressing TAMs in redirecting cancer cells to preferentially disseminate to lymph nodes rather than to lungs, partially achieved by normalizing tumor blood vessels and promoting lymphangiogenesis.

An idiosyncratic zonated stroma encapsulates desmoplastic liver metastases and originates from injured liver.

A perimetastatic capsule is a strong positive prognostic factor in liver metastases, but its origin remains unclear. Here, we systematically quantify the capsule's extent and cellular composition in 263 patients with colorectal cancer liver metastases to investigate its clinical significance and origin. We show that survival improves proportionally with increasing encapsulation and decreasing tumor-hepatocyte contact. Immunostaining reveals the gradual zonation of the capsule, transitioning from benign-like NGFRhigh stroma at the liver edge to FAPhigh stroma towards the tumor. Encapsulation correlates with decreased tumor viability and preoperative chemotherapy. In mice, chemotherapy and tumor cell ablation induce capsule formation. Our results suggest that encapsulation develops where tumor invasion into the liver plates stalls, representing a reparative process rather than tumor-induced desmoplasia. We propose a model of metastases growth, where the efficient tumor colonization of the liver parenchyma and a reparative liver injury reaction are opposing determinants of metastasis aggressiveness.

A PDGFRB- and CD40-targeting bispecific AffiMab induces stroma-targeted immune cell activation.

CD40 agonism by systemic administration of CD40 monoclonal antibodies has been explored in clinical trials for immunotherapy of cancer, uncovering enormous potential, but also dosing challenges in terms of systemic toxicity. CD40-dependent activation of antigen presenting cells is dependent on crosslinking of the CD40 receptor. Here we exploited this requisite by coupling crosslinking to cancer-receptor density by dual-targeting of CD40 and platelet-derived growth factor receptor beta (PDGFRB), which is highly expressed in the stroma of various types of tumors. A novel PDGFRBxCD40 Fc-silenced bispecific AffiMab was developed to this end to test whether it is possible to activate CD40 in a PDGFRB-targeted manner. A PDGFRB-binding Affibody molecule was fused to each heavy chain of an Fc-silenced CD40 agonistic monoclonal antibody to obtain a bispecific "AffiMab". Binding of the AffiMab to both PDGFRB and CD40 was confirmed by surface plasmon resonance, bio-layer interferometry and flow cytometry, through analysis of cells expressing respective target. In a reporter assay, the AffiMab displayed increased CD40 potency in the presence of PDGFRB-conjugated beads, in a manner dependent on PDGFRB amount/bead. To test the concept in immunologically relevant systems with physiological levels of CD40 expression, the AffiMab was tested in human monocyte-derived dendritic cells (moDCs) and B cells. Expression of activation markers was increased in moDCs specifically in the presence of PDGFRB-conjugated beads upon AffiMab treatment, while the Fc-silenced CD40 mAb did not stimulate CD40 activation. As expected, the AffiMab did not activate moDCs in the presence of unconjugated beads. Finally, in a co-culture experiment, the AffiMab activated moDCs and B cells in the presence of PDGFRB-expressing cells, but not in co-cultures with PDGFRB-negative cells. Collectively, these results suggest the possibility to activate CD40 in a PDGFRB-targeted manner in vitro. This encourages further investigation and the development of such an approach for the treatment of solid cancers.

Vessel size as a marker of survival in estrogen receptor positive breast cancer.

PURPOSE: Angiogenesis is crucial for tumor growth and is one of the hallmarks of cancer. In this study, we analyzed microvessel density, vessel median size, and perivascular a-SMA expression as prognostic biomarkers in breast cancer. METHODS: Dual IHC staining was performed where alpha-SMA antibodies were used together with antibodies against the endothelial cell marker CD34. Digital images of stainings were analyzed to extract quantitative data on vessel density, vessel size, and perivascular alpha-SMA status. RESULTS: The analyses in the discovery cohort (n = 108) revealed a statistically significant relationship between large vessel size and shorter disease-specific survival (p = 0.007, log-rank test; p = 0.01, HR 3.1; 95% CI 1.3-7.4, Cox-regression analyses). Subset analyses indicated that the survival association of vessel size was strengthened in ER + breast cancer. To consolidate these findings, additional analyses were performed on a validation cohort (n = 267) where an association between large vessel size and reduced survival was also detected in ER + breast cancer (p = 0.016, log-rank test; p = 0.02; HR 2.3, 95% CI 1.1-4.7, Cox-regression analyses). CONCLUSION: Alpha-SMA/CD34 dual-IHC staining revealed breast cancer heterogeneity regarding vessel size, vessel density, and perivascular a-SMA status. Large vessel size was linked to shorter survival in ER + breast cancer.

Characterization of the bone marrow niche in patients with chronic myeloid leukemia identifies CXCL14 as a new therapeutic option.

Although tyrosine kinase inhibitors (TKIs) are effective in treating chronic myeloid leukemia (CML), they often fail to eradicate the leukemia-initiating stem cells (LSCs), causing disease persistence and relapse. Evidence indicates that LSC persistence may be because of bone marrow (BM) niche protection; however, little is known about the underlying mechanisms. Herein, we molecularly and functionally characterize BM niches in patients with CML at diagnosis and reveal the altered niche composition and function in these patients. Long-term culture initiating cell assay showed that the mesenchymal stem cells from patients with CML displayed an enhanced supporting capacity for normal and CML BM CD34+CD38- cells. Molecularly, RNA sequencing detected dysregulated cytokine and growth factor expression in the BM cellular niches of patients with CML. Among them, CXCL14 was lost in the BM cellular niches in contrast to its expression in healthy BM. Restoring CXCL14 significantly inhibited CML LSC maintenance and enhanced their response to imatinib in vitro, and CML engraftment in vivo in NSG-SGM3 mice. Importantly, CXCL14 treatment dramatically inhibited CML engraftment in patient-derived xenografted NSG-SGM3 mice, even to a greater degree than imatinib, and this inhibition persisted in patients with suboptimal TKI response. Mechanistically, CXCL14 upregulated inflammatory cytokine signaling but downregulated mTOR signaling and oxidative phosphorylation in CML LSCs. Together, we have discovered a suppressive role of CXCL14 in CML LSC growth. CXCL14 might offer a treatment option targeting CML LSCs.

Fibroblast subsets in non-small cell lung cancer: Associations with survival, mutations, and immune features.

BACKGROUND: Cancer-associated fibroblasts (CAFs) are molecularly heterogeneous mesenchymal cells that interact with malignant cells and immune cells and confer anti- and protumorigenic functions. Prior in situ profiling studies of human CAFs have largely relied on scoring single markers, thus presenting a limited view of their molecular complexity. Our objective was to study the complex spatial tumor microenvironment of non-small cell lung cancer (NSCLC) with multiple CAF biomarkers, identify novel CAF subsets, and explore their associations with patient outcome. METHODS: Multiplex fluorescence immunohistochemistry was employed to spatially profile the CAF landscape in 2 population-based NSCLC cohorts (n = 636) using antibodies against 4 fibroblast markers: platelet-derived growth factor receptor-alpha (PDGFRA) and -beta (PDGFRB), fibroblast activation protein (FAP), and alpha-smooth muscle actin (αSMA). The CAF subsets were analyzed for their correlations with mutations, immune characteristics, and clinical variables as well as overall survival. RESULTS: Two CAF subsets, CAF7 (PDGFRA-/PDGFRB+/FAP+/αSMA+) and CAF13 (PDGFRA+/PDGFRB+/FAP-/αSMA+), showed statistically significant but opposite associations with tumor histology, driver mutations (tumor protein p53 [TP53] and epidermal growth factor receptor [EGFR]), immune features (programmed death-ligand 1 and CD163), and prognosis. In patients with early stage tumors (pathological tumor-node-metastasis IA-IB), CAF7 and CAF13 acted as independent prognostic factors. CONCLUSIONS: Multimarker-defined CAF subsets were identified through high-content spatial profiling. The robust associations of CAFs with driver mutations, immune features, and outcome suggest CAFs as essential factors in NSCLC progression and warrant further studies to explore their potential as biomarkers or therapeutic targets. This study also highlights multiplex fluorescence immunohistochemistry-based CAF profiling as a powerful tool for the discovery of clinically relevant CAF subsets.

Visualization and quality control tools for large-scale multiplex tissue analysis in TissUUmaps3.

Large-scale multiplex tissue analysis aims to understand processes such as development and tumor formation by studying the occurrence and interaction of cells in local environments in, for example, tissue samples from patient cohorts. A typical procedure in the analysis is to delineate individual cells, classify them into cell types, and analyze their spatial relationships. All steps come with a number of challenges, and to address them and identify the bottlenecks of the analysis, it is necessary to include quality control tools in the analysis workflow. This makes it possible to optimize the steps and adjust settings in order to get better and more precise results. Additionally, the development of automated approaches for tissue analysis requires visual verification to reduce skepticism with regard to the accuracy of the results. Quality control tools could be used to build users' trust in automated approaches. In this paper, we present three plugins for visualization and quality control in large-scale multiplex tissue analysis of microscopy images. The first plugin focuses on the quality of cell staining, the second one was made for interactive evaluation and comparison of different cell classification results, and the third one serves for reviewing interactions of different cell types.

High Density of NRF2 Expression in Malignant Cells Is Associated with Increased Risk of CNS Metastasis in Early-Stage NSCLC.

Nuclear factor erythroid 2-related factor 2 (NRF2) protein expression promotes cancer progression in non-small cell lung cancer (NSCLC). However, its role in the clinical setting has not been established. We retrospectively analyzed data from 304 patients with surgically removed NSCLC. Multiplex antibody staining of NRF2 and thioredoxin reductase 1 (TrxR1) was conducted and scored in cytokeratin-positive (CK+) cells within the whole-tissue core as well as the tumor and stromal compartments of each tissue microarray (TMA) core. A high density of NRF2+/CK+ cells in the whole-tissue core compartment was correlated with a higher risk of central nervous system (CNS) relapse OR = 7.36 (95% CI: 1.64-33.06). The multivariate analysis showed an OR = 8.00 (95% CI: 1.70-37.60) for CNS relapse in NRF2+/CK+ high-density cases. The density of TrxR1+/CK+ cells failed to show any statistically significant risk of relapse. The OS analyses for NRF2+/CK+ and TrxR1+/CK+ cell density failed to show any statistical significance. This is the first study to report a correlation between NRF2+/CK+ cell density and the risk of CNS relapse in early-stage NSCLC. The results of our study may impact the follow-up strategy for early-stage NSCLC patients and eventually improve their prognosis.

Machine learning for cell classification and neighborhood analysis in glioma tissue.

Multiplexed and spatially resolved single-cell analyses that intend to study tissue heterogeneity and cell organization invariably face as a first step the challenge of cell classification. Accuracy and reproducibility are important for the downstream process of counting cells, quantifying cell-cell interactions, and extracting information on disease-specific localized cell niches. Novel staining techniques make it possible to visualize and quantify large numbers of cell-specific molecular markers in parallel. However, due to variations in sample handling and artifacts from staining and scanning, cells of the same type may present different marker profiles both within and across samples. We address multiplexed immunofluorescence data from tissue microarrays of low-grade gliomas and present a methodology using two different machine learning architectures and features insensitive to illumination to perform cell classification. The fully automated cell classification provides a measure of confidence for the decision and requires a comparably small annotated data set for training, which can be created using freely available tools. Using the proposed method, we reached an accuracy of 83.1% on cell classification without the need for standardization of samples. Using our confidence measure, cells with low-confidence classifications could be excluded, pushing the classification accuracy to 94.5%. Next, we used the cell classification results to search for cell niches with an unsupervised learning approach based on graph neural networks. We show that the approach can re-detect specialized tissue niches in previously published data, and that our proposed cell classification leads to niche definitions that may be relevant for sub-groups of glioma, if applied to larger data sets.

High tumor cell platelet-derived growth factor receptor beta expression is associated with shorter survival in malignant pleural epithelioid mesothelioma.

Malignant pleural mesothelioma (MPM) has a rich stromal component containing mesenchymal fibroblasts. However, the properties and interplay of MPM tumor cells and their surrounding stromal fibroblasts are poorly characterized. Our objective was to spatially profile known mesenchymal markers in both tumor cells and associated fibroblasts and correlate their expression with patient survival. The primary study cohort consisted of 74 MPM patients, including 16 patients who survived at least 60 months. We analyzed location-specific tissue expression of seven fibroblast markers in clinical samples using multiplexed fluorescence immunohistochemistry (mfIHC) and digital image analysis. Effect on survival was assessed using Cox regression analyses. The outcome measurement was all-cause mortality. Univariate analysis revealed that high expression of secreted protein acidic and cysteine rich (SPARC) and fibroblast activation protein in stromal cells was associated with shorter survival. Importantly, high expression of platelet-derived growth factor receptor beta (PDGFRB) in tumor cells, but not in stromal cells, was associated with shorter survival (hazard ratio [HR] = 1.02, p < 0.001). A multivariable survival analysis adjusted for clinical parameters and stromal mfIHC markers revealed that tumor cell PDGFRB and stromal SPARC remained independently associated with survival (HR = 1.01, 95% confidence interval [CI] = 1.00-1.03 and HR = 1.05, 95% CI = 1.00-1.11, respectively). The prognostic effect of PDGFRB was validated with an artificial intelligence-based analysis method and further externally validated in another cohort of 117 MPM patients. In external validation, high tumor cell PDGFRB expression associated with shorter survival, especially in the epithelioid subtype. Our findings suggest PDGFRB and SPARC as potential markers for risk stratification and as targets for therapy.

High PDGFRb Expression Predicts Resistance to Radiotherapy in DCIS within the SweDCIS Randomized Trial.

PURPOSE: This study analyzes the potential of stromal platelet-derived growth factor receptor-beta (PDGFRb) expression as biomarker for radiotherapy (RT) benefit on ipsilateral breast events (IBE) in ductal carcinoma in situ (DCIS). Improved identification of DCIS patients refractory to adjuvant whole-breast RT is needed. Predictive biomarker studies in DCIS have focused on tumor cell features rather than the tumor-associated stroma, despite growing evidence of its influence on therapy efficiency. EXPERIMENTAL DESIGN: Samples from the Swedish randomized radiotherapy DCIS trial (SweDCIS) were subjected to IHC analysis for stromal PDGFRb expression. IBE incidence at 10 years after breast-conserving surgery was the primary endpoint. Interactions between marker and treatment were analyzed. RESULTS: PDGFRb score was predictive for RT benefit with regard to IBE (P interaction = 0.002 and P interaction = 0.008 adjusted multivariably). Patients of the PDGFRblow group had a strong benefit from RT regarding IBE risk [HR, 0.23; 95% confidence interval (CI), 0.12-0.45; P < 0.001] with an absolute risk reduction of 21% (cumulative risk 7% vs. 28%) at 10 years. No significant risk reduction by RT was observed for patients of the PDGFRbhigh group (HR, 0.83; 0.51-1.34; P = 0.444; cumulative risk 22% vs. 25%). The RT response-predictive effect of stromal PDGFRb was equally strong in analyses for in situ and invasive IBE when analyzed separately (in situ IBE: P = 0.029; invasive IBE: P = 0.044). CONCLUSIONS: Results suggest high stromal PDGFRb expression as a novel biomarker identifying DCIS patients who are refractory to standard whole-breast adjuvant RT. The data imply previously unrecognized fibroblast-mediated modulation of radiosensitivity of DCIS, which should be further explored from mechanistic and targeting perspectives.

CD11c-CD8 Spatial Cross Presentation: A Novel Approach to Link Immune Surveillance and Patient Survival in Soft Tissue Sarcoma.

Checkpoint inhibitors are slowly being introduced in the care of specific sarcoma subtypes such as undifferentiated pleomorphic sarcoma, alveolar soft part sarcoma, and angiosarcoma even though formal indication is lacking. Proper biomarkers to unravel potential immune reactivity in the tumor microenvironment are therefore expected to be highly warranted. In this study, intratumoral spatial cross presentation was investigated as a novel concept where immune cell composition in the tumor microenvironment was suggested to act as a proxy for immune surveillance. Double immunohistochemistry revealed a prognostic role of direct spatial interactions between CD11c+ antigen-presenting cells (APCs) and CD8+ cells in contrast to each marker alone in a soft tissue sarcoma (STS) cohort of 177 patients from the Karolinska University Hospital (MFS p = 0.048, OS p = 0.025). The survival benefit was verified in multivariable analysis (MFS p = 0.012, OS p = 0.004). Transcriptomics performed in the TCGA sarcoma cohort confirmed the prognostic value of combining CD11c with CD8 (259 patients, p = 0.005), irrespective of FOXP3 levels and in a CD274 (PD-LI)-rich tumor microenvironment. Altogether, this study presents a histopathological approach to link immune surveillance and patient survival in STS. Notably, spatial cross presentation as a prognostic marker is distinct from therapy response-predictive biomarkers such as immune checkpoint molecules of the PD-L1/PD1 pathway.

Stromal FAP is an independent poor prognosis marker in non-small cell lung adenocarcinoma and associated with p53 mutation.

OBJECTIVES: Fibroblasts regulate tumor growth and immune surveillance. Here, we study FAP, PDGFßR and α-SMA fibroblast markers in a well-annotated clinical cohort of non-small-cell lung cancer (NSCLC) for analyses of associations with immune cell infiltration, mutation status and survival. MATERIALS AND METHODS: A well-annotated NSCLC cohort was subjected to IHC analyses of stromal expression of FAP, PDGFßR and α-SMA and of stromal CD8 density. Fibroblast markers-related measurements were analyzed with regard to potential associations with CD8 density, cancer genetic driver mutations, survival and PD-L1 expression in the whole NSCLC cohort and in subsets of patients. RESULTS: High stromal FAP expression was identified as an independent poor prognostic marker in the whole study population (HR 1.481; 95 % CI, 1.012-2.167, p = 0.023) and in the histological subset of adenocarcinoma (HR 1.720; 95 % CI, 1.126-2.627, p = 0.012). Among patients with adenocarcinoma, a particularly strong association of FAP with poor survival was detected in patients with low stromal CD8 infiltration, and in other subpopulations identified by specific clinical characteristics; elderly patients, females, non-smokers and patients with normal ECOG performance status. α-SMA expression was negatively associated with CD8 infiltration in non-smokers, but none of the fibroblast markers expression was associated with CD8 density in the whole study population. Significant associations were detected between presence of p53 mutations and high α-SMA (p = 0.003) and FAP expression (p < 0.001). CONCLUSION: The study identifies FAP intensity as a candidate independent NSCLC prognostic biomarker. The study also suggests continued analyses of the relationships between genetic driver mutations and the composition of tumor stroma, as well as continued probing of marker-defined fibroblasts as NSCLC subset-specific modifiers of immune surveillance and outcome.

Prognostic and predictive impact of stroma cells defined by PDGFRb expression in early breast cancer: results from the randomized SweBCG91RT trial.

PURPOSE: Predictive biomarkers are needed to aid the individualization of radiotherapy (RT) in breast cancer. Cancer-associated fibroblasts have been implicated in tumor radioresistance and can be identified by platelet-derived growth factor receptor-beta (PDGFRb). This study aims to analyze how PDGFRb expression affects RT benefit in a large randomized RT trial. METHODS: PDGFRb was assessed by immunohistochemistry on tissue microarrays from 989 tumors of the SweBCG91RT trial, which enrolled lymph node-negative, stage I/IIA breast cancer patients randomized to RT after breast-conserving surgery. Outcomes were analyzed at 10 years for ipsilateral breast tumor recurrence (IBTR) and any recurrence and 15 years for breast cancer specific death (BCSD). RESULTS: PDGFRb expression correlated with estrogen receptor negativity and younger age. An increased risk for any recurrence was noted in univariable analysis for the medium (HR 1.58, CI 95% 1.11-2.23, p = 0.011) or PDGFRb high group (1.49, 1.06-2.10, p = 0.021) compared to the low group. No differences in IBTR or BCSD risk were detected. RT benefit regarding IBTR risk was significant in the PDGFRb low (0.29, 0.12-0.67, p = 0.004) and medium (0.31, 0.16-0.59, p < 0.001) groups but not the PDGFRb high group (0.64, 0.36-1.11, p = 0.110) in multivariable analysis. Likewise, risk reduction for any recurrence was less pronounced in the PDGFRb high group. No significant interaction between RT and PDGFRb-score could be detected. CONCLUSION: A higher PDGFRb-score conferred an increased risk of any recurrence, which partly can be explained by its association with estrogen receptor negativity and young age. Reduced RT benefit was noted among patients with high PDGFRb, however without significant interaction.

Prognostic Interactions between FAP+ Fibroblasts and CD8a+ T Cells in Colon Cancer.

Inter-case variations in immune cell and fibroblast composition are associated with prognosis in solid tumors, including colon cancer. A series of experimental studies suggest immune-modulatory roles of marker-defined fibroblast populations, including FAP-positive fibroblasts. These studies imply that the fibroblast status of tumors might affect the prognostic significance of immune-related features. Analyses of a population-based colon cancer cohort demonstrated good prognosis associations of FAP intensity and CD8a density. Notably, a significant prognostic interaction was detected between these markers (p = 0.013 in nonadjusted analyses and p = 0.003 in analyses adjusted for cofounding factors) in a manner where the good prognosis association of CD8 density was restricted to the FAP intensity-high group. This prognostic interaction was also detected in an independent randomized trial-derived colon cancer cohort (p = 0.048 in nonadjusted analyses). In the CD8-high group, FAP intensity was significantly associated with a higher total tumor density of FoxP3-positive immune cells and a higher ratio of epithelial-to-stromal density of CD8a T cells. The study presents findings relevant for the ongoing efforts to improve the prognostic performance of CD8-related markers and should be followed by additional validation studies. Furthermore, findings support, in general, earlier model-derived studies implying fibroblast subsets as clinically relevant modulators of immune surveillance. Finally, the associations between FAP intensity and specific immune features suggest mechanisms of fibroblast-immune crosstalk with therapeutic potential.

High density of stroma-localized CD11c-positive macrophages is associated with longer overall survival in high-grade serous ovarian cancer.

OBJECTIVE: Pre-clinical studies have identified marker- and tumor compartment-defined functionally distinct macrophage subsets. Our study analyzes marker-defined macrophage subsets in different tumor compartments of high-grade serous ovarian cancer (HGSC). METHODS: A discovery cohort (N = 113) was subjected to immunohistochemistry (IHC) analyses. CD68-positivity was confirmed for CD11c-, CD80- and CD163-positive cells. Subset-marker-positive cells were scored in the total tumor and in four tumor compartments. Correlation analyses investigated co-expression of subsets, relationship to CD8+ cells and survival associations. A validation cohort (N = 121) was used to confirm selected findings from the discovery cohort. RESULTS: CD163-positve cells was the most abundant subtype in all compartments. CD11c and CD163 subsets were strongly correlated with each other in stroma and epithelial areas, whereas CD80 and CD163 were correlated in epithelial areas. CD80 and CD11c in perivascular areas showed low correlations. Strong associations were detected between CD8 and CD80 in the tumor epithelium-dominated areas, and between CD8 and CD11c in stroma areas. High stromal CD11c density was associated with a longer median overall survival in the discovery cohort (HR 0.39; CI 95%, 0.23-0.68; p = 0.001) and in the validation cohort (HR 0.46; CI 95%, 0.22-0.93; p = 0.03). CONCLUSIONS: Our study supports the existence of clinically relevant marker- and localization defined macrophage subsets in HGSC, which are independently regulated. Moreover, it suggests stromal CD11c as a novel prognostic marker in HGSC.

Cytotoxic T-cells mediate exercise-induced reductions in tumor growth.

Exercise has a wide range of systemic effects. In animal models, repeated exertion reduces malignant tumor progression, and clinically, exercise can improve outcome for cancer patients. The etiology of the effects of exercise on tumor progression are unclear, as are the cellular actors involved. We show here that in mice, exercise-induced reduction in tumor growth is dependent on CD8+ T cells, and that metabolites produced in skeletal muscle and excreted into plasma at high levels during exertion in both mice and humans enhance the effector profile of CD8+ T-cells. We found that activated murine CD8+ T cells alter their central carbon metabolism in response to exertion in vivo, and that immune cells from trained mice are more potent antitumor effector cells when transferred into tumor-bearing untrained animals. These data demonstrate that CD8+ T cells are metabolically altered by exercise in a manner that acts to improve their antitumoral efficacy.

Exercise affects almost all tissues in the body, and scientists have found that being physically active can reduce the risk of several types of cancer as well as improving outcomes for cancer patients. However, it is still unknown how exercise exerts its protective effects. One of the hallmarks of cancer is the ability of cancer cells to evade detection by the immune system, which can in some cases stop the body from eliminating tumor cells. Rundqvist et al. used mice to investigate how exercise helps the immune system act against tumor progression. They found that when mice exercised, tumor growth was reduced, and this decrease in growth depended on the levels of a specific type of immune cell, the CD8+ T cell, circulating in the blood. Additionally, Rundqvist et al. found that CD8+ T cells were made more effective by molecules that muscles released into the blood during exercise. Isolating immune cells after intense exercise showed that these super-effective CD8+ T cells alter how they use molecules for energy production after exertion. Next, immune cells from mice that had exercised frequently were transferred into mice that had not exercised, where they were more effective against tumor cells than the immune cells from untrained mice. These results demonstrate that CD8+ T cells are altered by exercise to improve their effectiveness against tumors. The ability of T cells to identify and eliminate cancer cells is essential to avoid tumor growth, and is one of the foundations of current immune therapy treatments. Exercise could improve the outcome of these treatments by increasing the activation of the immune system, making tumor-fighting cells more effective.