Spatially distinct tumor immune microenvironments stratify triple-negative breast cancers

Tissue Selection for PD-L1 Testing in Triple Negative Breast Cancer (TNBC)

Atezolizumab in combination with nab-paclitaxel has been introduced for the treatment of locally advanced or recurrent triple negative breast cancer (TNBC). Patient selection relies on the use of immunohistochemistry using a specific monoclonal PD-L1 antibody (clone SP142) in a tightly controlled companion diagnostic test (CDx) with a defined interpretative algorithm. Currently there are no standardized recommendations for selecting the optimal tissue to be tested and there is limited data to support decision making, raising the possibility that tissue selection may bias test results. We compared PD-L1 SP142 assessment in a collection of 73 TNBC cases with matched core biopsies and excision samples. There was good correlation between PD-L1-positive core biopsy and subsequent excision, but we found considerable discrepancy between PD-L1 negative core biopsy and matched excision, with a third of cases found negative on core biopsies converting to positive upon examination of the excision tissue. In view of these findings, we developed a workflow for the clinical testing of TNBC for PD-L1 and implemented it in a central referral laboratory. We present audit data from the clinical PD-L1 testing relating to 2 years of activities, indicating that implementation of this workflow results in positivity rates in our population of TNBC similar to those of IMpassion130 clinical trial. We also developed an online atlas with a precise numerical annotation to aid pathologists in the interpretation of PD-L1 scoring in TNBC.

Recent advances in therapeutic strategies for triple-negative breast cancer

Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer (BC) with a poor prognosis. Current treatment options are limited to surgery, adjuvant chemotherapy and radiotherapy; however, a proportion of patients have missed the surgical window at the time of diagnosis. TNBC is a highly heterogeneous cancer with specific mutations and aberrant activation of signaling pathways. Hence, targeted therapies, such as those targeting DNA repair pathways, androgen receptor signaling pathways, and kinases, represent promising treatment options against TNBC. In addition, immunotherapy has also been demonstrated to improve overall survival and response in TNBC. In this review, we summarize recent key advances in therapeutic strategies based on molecular subtypes in TNBC.

Replenishment of myeloid-derived suppressor cells (MDSCs) overrides CR-mediated protection against tumor growth in a murine model of triple-negative breast cancer

Caloric restriction (CR) is the leading non-pharmacological intervention to delay induced and spontaneous tumors in pre-clinical models. These effects of CR are largely attributed to canonical inhibition of pro-growth pathways. However, our recent data suggest that CR impairs primary tumor growth and cancer progression in the murine 4T1 model of triple negative breast cancer (TNBC), at least in part, through reduced frequency of the myeloid-derived suppressor cells (MDSC). In the present study, we sought to determine whether injection of excess MDSCs could block regression in 4T1 tumor growth and metastatic spread in BALB/cJ female mice undergoing daily CR. Our findings show that MDSC injection impeded CR-mediated protection against tumor growth without increasing lung metastatic burden. Overall, these results reveal that CR can slow cancer progression by affecting immune suppressive cells.Impact statement: Inoculation of MDSCs from donor mice effectively impedes the ability of calorie restriction to protect against primary tumor growth without impacting lung metastatic burden in recipient animals.

Triple negative breast cancer: Pitfalls and progress

Triple negative breast cancer (TNBC) is characterized by the lack of estrogen and progesterone receptor expression and lacks HER2 overexpression or gene amplification. It accounts for 10–15% of incident breast cancers and carries the worst prognosis. TNBC is overrepresented among Black and pre-menopausal women and is associated with significant psychological and treatment-related burdens, including financial toxicity. Like other breast cancers, TNBC is biologically heterogeneous, leading to diverse clinical and epidemiological behaviors, however, unlike the other clinical subtypes, in TNBC we still lack tumor-specific targeted therapy. Early TNBC outcomes have improved due to the intensification of therapies, including improvements in polychemotherapy and the addition of immunotherapy. Future efforts are needed to identify targetable aberrations for specific drug therapy, prevent immune evasion, and increase social-economic support. Given that the name TNBC illustrates its lack of specifically targeted and effective therapy, we look forward to being able to retire the name in favor of a group of targetable entities within what is now called “TNBC”.

The Landscape of Tumor-Infiltrating Immune Cells in Feline Mammary Carcinoma: Pathological and Clinical Implications

Feline mammary carcinoma (FMC) shares key molecular and clinicopathological features with human breast cancer. We have herein studied the inflammatory infiltrate of FMC in order to uncover potential therapeutic targets and prognostic markers. To this end, the expression of different markers (CD3, CD4, CD8, CD20, CD56, FoxP3, CD68 and CD163) was analyzed in total, stromal (s) and intratumoral (i) tumor-infiltrating lymphocytes (TILs) and tumor-associated macrophages (TAMs), in 73 feline mammary carcinomas. The results revealed that higher percentages of sCD8⁺ TILs were associated with longer disease-free survival (p = 0.05) and overall survival (p = 0.021). Additionally, higher percentages of iCD4⁺ TILs correlated with positive lymph node status (p = 0.003), whereas CD163⁺ TAMs were associated with undifferentiated tumors (p = 0.013). In addition, sCD3⁺ (p = 0.033), sCD8⁺ (p = 0.044) and sCD68⁺ (p = 0.023) immune cells were enriched in triple negative normal-like carcinomas compared to other subtypes. Altogether, our results suggest that specific subsets of immune cells may play a major role in clinical outcome of cats with mammary carcinoma, resembling what has been reported in human breast cancer. These data further support the relevance of the feline model in breast cancer studies.

Precision Breast Cancer Medicine: Early Stage Triple Negative Breast Cancer-A Review of Molecular Characterisation, Therapeutic Targets and Future Trends

Personalised approaches to the management of all solid tumours are increasing rapidly, along with wider accessibility for clinicians. Advances in tumour characterisation and targeted therapies have placed triple-negative breast cancers (TNBC) at the forefront of this approach. TNBC is a highly heterogeneous disease with various histopathological features and is driven by distinct molecular alterations. The ability to tailor individualised and effective treatments for each patient is of particular importance in this group due to the high risk of distant recurrence and death. The mainstay of treatment across all subtypes of TNBC has historically been cytotoxic chemotherapy, which is often associated with off-target tissue toxicity and drug resistance. Neoadjuvant chemotherapy is commonly used as it allows close monitoring of early treatment response and provides valuable prognostic information. Patients who achieve a complete pathological response after neoadjuvant chemotherapy are known to have significantly improved long-term outcomes. Conversely, poor responders face a higher risk of relapse and death. The identification of those subgroups that are more likely to benefit from breakthroughs in the personalised approach is a challenge of the current era where several targeted therapies are available. This review presents an overview of contemporary practice, and promising future trends in the management of early TNBC. Platinum chemotherapy, DNA damage response (DDR) inhibitors, immune checkpoint inhibitors, inhibitors of the PI3K-AKT-mTOR, and androgen receptor (AR) pathways are some of the increasingly studied therapies which will be reviewed. We will also discuss the growing evidence for less-developed agents and predictive biomarkers that are likely to contribute to the forthcoming advances in this field. Finally, we will propose a framework for the personalised management of TNBC based upon the integration of clinico-pathological and molecular features to ensure that long-term outcomes are optimised.

Research progress on immunotherapy in triple‑negative breast cancer (Review)

Triple-negative breast cancer (TNBC) is a highly heterogeneous and aggressive malignancy. Due to the absence of estrogen receptors and progesterone receptors and the lack of overexpression of human epidermal growth factor receptor 2, TNBC responds poorly to endocrine and targeted therapies. As a neoadjuvant therapy, chemotherapy is usually the only option for TNBC; however, chemotherapy may induce tumor resistance. The emergence of immunotherapy as an adjuvant therapy is expected to make up for the deficiency of chemotherapy. Most of the research on immunotherapies has been performed on advanced metastatic TNBC, which has provided significant clinical benefits. In the present review, possible immunotherapy targets and ongoing immunotherapy strategies were discussed. In addition, progress in research on immune checkpoint inhibitors in early TNBC was outlined.

Dynamic CD8+ T Cell Cooperation with Macrophages and Monocytes for Successful Cancer Immunotherapy

Simple Summary

Innate and adaptive immunity mutually regulate one another in a dynamic fashion during immune responses. In infectious contexts, positive interactions between macrophages, monocytes and T cells are well recognized, but this is not the case in the field of cancer, where the growth of tumors disturbs the immune response. However, recent advances revealed that successful immunotherapy profoundly remodels the tumor microenvironment, promoting the activation of both T cells and myeloid cells. This review highlights the studies that hint at positive CD8⁺ T cell cooperation with monocytes and macrophages in this context, and discusses the potential mechanisms behind this.

Abstract

The essential roles endorsed by macrophages and monocytes are well established in response to infections, where they contribute to launching the differentiation of specific T-lymphocytes for long-term protection. This knowledge is the result of dynamic studies that can inspire the cancer field, particularly now that cancer immunotherapies elicit some tumor regression. Indeed, immune responses to cancer have mainly been studied after tumors have escaped immune attacks. In particular, the suppressive functions of macrophages were revealed in this context, introducing an obvious bias across the literature. In this review, we will focus on the ways inwhich monocytes and macrophages cooperate with T-lymphocytes, leading to successful immune responses. We will bring together the preclinical studies that have revealed the existence of such positive cooperation in the cancer field, and we will place particular emphasis on proposing the underlying mechanisms. Finally, we will give some perspectives to decipher the functional roles of such T-cell and myeloid cell interactions in the frame of human cancer immunotherapy.

GM-CSF derived from the inflammatory microenvironment potentially enhanced PD-L1 expression on tumor-associated macrophages in human breast cancer

Ever since immune checkpoint inhibitors have been approved for anti-cancer therapy in several cancers, including triple-negative breast cancer, the significance of programmed death-1 ligand 1 (PD-L1) expression in the tumor immune microenvironment has been a topic of interest. In the present study, we investigated the detailed mechanisms of PD-L1 overexpression on tumor-associated macrophages (TAMs) in breast cancer. In in vitro culture studies using human monocyte-derived macrophages, lymphocytes, and breast cancer cell lines, PD-L1 overexpression on macrophages was induced by the conditioned medium (CM) of activated lymphocytes, but not that of cancer cells. Granulocyte–macrophage colony-stimulating factor (GM-CSF) derived from activated lymphocytes was found to be involved in PD-L1 overexpression, in addition to interferon (IFN)-γ, via STAT3 pathway activation. Macrophages suppressed lymphocyte activation, and this inhibition was impaired by PD-1 blocking. The CM of activated lymphocytes also induced the overexpression of PD-L2, but GM-CSF did not affect PD-L2 expression. In the murine E0771 breast cancer model, anti-GM-CSF therapy did not affect PD-L1 expression on TAMs, and the mechanisms of PD-L1 expression on TAMs might differ between humans and mice. However, not only PD-L1, but also PD-L2 was overexpressed on TAMs in the E0771 tumor model, and their expression levels were significantly lower in the tumors in nude mice than in wild-type mice. Anti-PD-L1 antibody and anti-PD-L2 antibody synergistically inhibited E0771 tumor development. In conclusion, PD-L1 and PD-L2 were overexpressed on TAMs, and they potentially contributed to immunosuppression. The GM-CSF-STAT3 pathway is thought to represent a new mechanism of PD-L1 overexpression on TAMs in human breast cancer microenvironment.

Quantifying Spatial Heterogeneity of Tumor-Infiltrating Lymphocytes to Predict Survival of Individual Cancer Patients

Tumor-infiltrating lymphocytes (TILs), identified on HE-stained histopathological images in the cancer area, are indicators of the adaptive immune response against cancers and play a major role in personalized cancer immunotherapy. Recent works indicate that the spatial organization of TILs may be prognostic of disease-specific survival and recurrence. However, there are a limited number of methods that were proposed and tested in analyses of the spatial structure of TILs. In this work, we evaluated 14 different spatial measures, including the one developed for other omics data, on 10,532 TIL maps from 23 cancer types in terms of reproducibility, uniqueness, and impact on patient survival. For each spatial measure, 16 different scenarios for the definition of prognostic factor were tested. We found no difference in survival prediction when TIL maps were stored as binary images or continuous TIL probability scores. When spatial measures were discretized into a low and high category, a higher correlation with survival was observed. Three measures with the highest cancer prognosis capability were spatial autocorrelation, GLCM M1, and closeness centrality. Most of the tested measures could be further tuned to increase prediction performance.

Multidimensional Molecular Profiling of Metastatic Triple-Negative Breast Cancer and Immune Checkpoint Inhibitor Benefit

PURPOSE

In metastatic triple-negative breast cancer (mTNBC), consistent biomarkers of immune checkpoint inhibitor (ICI) therapy benefit remain elusive. We evaluated the immune, genomic, and transcriptomic landscape of mTNBC in patients treated with ICIs.

METHODS

We identified 29 patients with mTNBC treated with pembrolizumab or atezolizumab, either alone (n = 9) or in combination with chemotherapy (n = 14) or targeted therapy (n = 6), who had tumor tissue and/or blood available before ICI therapy for whole-exome sequencing. RNA sequencing and CIBERSORTx-inferred immune population analyses were performed (n = 20). Immune cell populations and programmed death-ligand 1 expression were assessed using multiplexed immunofluorescence (n = 18). Clonal trajectories were evaluated via serial tumor/circulating tumor DNA whole-exome sequencing (n = 4). Association of biomarkers with progression-free survival and overall survival (OS) was assessed.

RESULTS

Progression-free survival and OS were longer in patients with high programmed death-ligand 1 expression and tumor mutational burden. Patients with longer survival also had a higher relative inferred fraction of CD8+ T cells, activated CD4+ memory T cells, M1 macrophages, and follicular helper T cells and enrichment of inflammatory gene expression pathways. A mutational signature of defective repair of DNA damage by homologous recombination was enriched in patients with both shorter OS and primary resistance. Exploratory analysis of clonal evolution among four patients treated with programmed cell death protein 1 blockade and a tyrosine kinase inhibitor suggested that clonal stability post-treatment was associated with short time to progression.

CONCLUSION

This study identified potential biomarkers of response to ICIs among patients with mTNBC: high tumor mutational burden; presence of CD8+, CD4 memory T cells, follicular helper T cells, and M1 macrophages; and inflammatory gene expression pathways. Pretreatment deficiencies in the homologous recombination DNA damage repair pathway and the absence of or minimal clonal evolution post-treatment may be associated with worse outcomes.

Cancer-associated fibroblasts suppress CD8+ T cell infiltration and confer resistance to immune checkpoint blockade

Immune checkpoint blockade (ICB) promotes anti-tumor immune responses and can result in durable patient benefit. However, response rates in breast cancer patients remain modest, stimulating efforts to discover novel treatment options. Cancer-associated fibroblasts (CAF) represent a major component of the breast tumor microenvironment and have known immunosuppressive functions in addition to their well-established roles in directly promoting tumor growth and metastasis. Here we utilized paired syngeneic mouse mammary carcinoma models to show that CAF abundance is associated with insensitivity to combination αCTLA-4 and αPD-L1 ICB. CAF-rich tumors exhibited an immunologically cold tumor microenvironment, with transcriptomic, flow cytometric, and quantitative histopathological analyses demonstrating a relationship between CAF density and a CD8+ T cell-excluded tumor phenotype. The CAF receptor Endo180 (Mrc2) is predominantly expressed on myofibroblastic CAFs, and its genetic deletion depleted a subset of αSMA-expressing CAFs and impaired tumor progression in vivo. Addition of wild-type, but not Endo180-deficient, CAFs in co-implantation studies restricted CD8+ T cell intratumoral infiltration, and tumors in Endo180 knockout mice exhibited increased CD8+ T cell infiltration and enhanced sensitivity to ICB compared to tumors in wild-type mice. Clinically, in a trial of melanoma patients, high MRC2 mRNA levels in tumors was associated with a poor response to αPD-1 therapy, highlighting the potential benefits of therapeutically targeting a specific CAF subpopulation in breast and other CAF-rich cancers to improve clinical responses to immunotherapy.

Immunity and Extracellular Matrix Characteristics of Breast Cancer Subtypes Based on Identification by T Helper Cells Profiling

Background

The therapeutic effect of immune checkpoint inhibitors on tumors is not only related to CD8+ effector T cells but also sufficiently related to CD4+ helper T (T_H) cells. The immune characteristics of breast cancer, including gene characteristics and tumor-infiltrating lymphocytes, have become significant biomarkers for predicting prognosis and immunotherapy response in recent years.

Methods

Breast cancer samples from The Cancer Genome Atlas (TCGA) database and triple-negative breast cancer (TNBC) samples from GSE31519 in the Gene Expression Omnibus (GEO) database were extracted and clustered based on gene sets representing T_H cell signatures. CIBERSORT simulations of immune cell components in the tumor microenvironment and gene set enrichment analyses (GSEAs) were performed in the different clusters to verify the classification of the subtypes. The acquisition of differentially expressed genes (DEGs) in the different clusters was further used for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The clinical information from different clusters was used for survival analysis. Finally, the surgical tissues of TNBC samples were stained by immunofluorescence staining and Masson’s trichrome staining to explore the correlation of T_H cell subtypes with extracellular matrix (ECM).

Results

The breast cancer samples from the datasets in TCGA database and GEO database were classified into T_H-activated and T_H-silenced clusters, which was verified by the immune cell components and enriched immune-related pathways. The DEGs of T_H-activated and T_H-silenced clusters were obtained. In addition to T_H cells and other immune-related pathways, ECM-related pathways were found to be enriched by DEGs. Furthermore, the survival data of TCGA samples and GSE31519 samples showed that the 10-year overall survival (p-value < 0.001) and 10-year event-free survival (p-value = 0.162) of the T_H-activated cluster were better, respectively. Fluorescent labeling of T_H cell subtypes and staining of the collagen area of surgical specimens further illustrated the relationship between T_H cell subtypes and ECM in breast cancer, among which high T_H1 infiltration was related to low collagen content (p-value < 0.001), while high T_H2 and T_reg infiltration contained more abundant collagen (p-value < 0.05) in TNBC. With regard to the relationship of T_H cell subtypes, T_H2 was positively correlated with T_reg (p-value < 0.05), while T_H1 was negatively correlated with both of them.

Conclusions

The immune and ECM characteristics of breast cancer subtypes based on T_H cell characteristics were revealed, and the relationship between different T_H cell subsets and ECM and prognosis was explored in this study. The crosstalk between ECM and T_H cell subtypes formed a balanced TME influencing the prognosis and treatment response in breast cancer, which suggests that the correlation between T_H cells and ECM needs to be further emphasized in future breast cancer studies.

B7-H4 correlates with clinical outcome and immunotherapeutic benefit in muscle-invasive bladder cancer

AIM

B7-H4, a sibling to PD-L1 in B7 family, has been reported to be a novel immune checkpoint that is prevalent among non-inflamed tumors. Herein, we attempt to explore the potential of B7-H4 in survival prediction and therapeutic guidance in muscle-invasive bladder cancer (MIBC) patients.

METHODS

This study included 391 patients from The Cancer Genome Atlas (TCGA) database and 122 patients from Zhongshan (ZS) Hospital. The evaluation of response to PD-L1 inhibitors was based on 270 patients in IMvigor210 cohort. Kaplan-Meier survival and multivariate analyses were performed to assess clinical outcomes in three cohorts. The correlation of B7-H4 expression with immune contexture and genomic alterations was analyzed based on immunohistochemistry, Microenvironment Cell Populations-counter (MCP-counter) tool, and whole-exome sequencing.

RESULTS

MIBC patients with the high level of B7-H4 expression (B7-H4^high) were found to possess an inferior overall and recurrence-free survival. Nonetheless, substantial clinical benefits of cisplatin-based chemotherapy and anti-PD-L1 immunotherapy were observed in these patients. After identifying a positive correlation between B7-H4 and tumor mutation burden (TMB), clinical benefits in B7-H4^high TMB^high subgroup were found to be the most upon PD-L1 blockade. Further studies revealed that B7-H4^high subgroup was featured by non-inflamed immune contexture and cell cycle-related gene alterations.

CONCLUSIONS

Despite adverse clinical outcomes, B7-H4^high patients possessed superior responsiveness to chemotherapy and immunotherapy. B7-H4 stratification could also synergize with TMB to pinpoint the patients who benefited most from immunotherapy. The clinical exploration of B7-H4 as a companion predictor could allow clinicians to direct proper therapeutic agents to patients.

A multimodal imaging workflow for monitoring CAR T cell therapy against solid tumor from whole-body to single-cell level

CAR T cell research in solid tumors often lacks spatiotemporal information and therefore, there is a need for a molecular tomography to facilitate high-throughput preclinical monitoring of CAR T cells. Furthermore, a gap exists between macro- and microlevel imaging data to better assess intratumor infiltration of therapeutic cells. We addressed this challenge by combining 3D µComputer tomography bioluminescence tomography (µCT/BLT), light-sheet fluorescence microscopy (LSFM) and cyclic immunofluorescence (IF) staining. Methods: NSG mice with subcutaneous AsPC1 xenograft tumors were treated with EGFR CAR T cell (± IL-2) or control BDCA-2 CAR T cell (± IL-2) (n = 7 each). Therapeutic T cells were genetically modified to co-express the CAR of interest and the luciferase CBR2opt. IL-2 was administered s.c. under the xenograft tumor on days 1, 3, 5 and 7 post-therapy-initiation at a dose of 25,000 IU/mouse. CAR T cell distribution was measured in 2D BLI and 3D µCT/BLT every 3-4 days. On day 6, 4 tumors were excised for cyclic IF where tumor sections were stained with a panel of 25 antibodies. On day 6 and 13, 8 tumors were excised from rhodamine lectin-preinjected mice, permeabilized, stained for CD3 and imaged by LSFM. Results: 3D µCT/BLT revealed that CAR T cells pharmacokinetics is affected by antigen recognition, where CAR T cell tumor accumulation based on target-dependent infiltration was significantly increased in comparison to target-independent infiltration, and spleen accumulation was delayed. LSFM supported these findings and revealed higher T cell accumulation in target-positive groups at day 6, which also infiltrated the tumor deeper. Interestingly, LSFM showed that most CAR T cells accumulate at the tumor periphery and around vessels. Surprisingly, LSFM and cyclic IF revealed that local IL-2 application resulted in early-phase increased proliferation, but long-term overstimulation of CAR T cells, which halted the early added therapeutic effect. Conclusion: Overall, we demonstrated that 3D µCT/BLT is a valuable non-isotope-based technology for whole-body cell therapy monitoring and investigating CAR T cell pharmacokinetics. We also presented combining LSFM and MICS for ex vivo 3D- and 2D-microscopy tissue analysis to assess intratumoral therapeutic cell distribution and status.

Classification of triple negative breast cancer by epithelial mesenchymal transition and the tumor immune microenvironment

Triple-negative breast cancer (TNBC) accounts for about 15–20% of all breast cancers and differs from other invasive breast cancer types because it grows and spreads rapidly, it has limited treatment options and typically worse prognosis. Since TNBC does not express estrogen or progesterone receptors and little or no human epidermal growth factor receptor (HER2) proteins are present, hormone therapy and drugs targeting HER2 are not helpful, leaving chemotherapy only as the main systemic treatment option. In this context, it would be important to find molecular signatures able to stratify patients into high and low risk groups. This would allow oncologists to suggest the best therapeutic strategy in a personalized way, avoiding unnecessary toxicity and reducing the high costs of treatment. Here we compare two independent patient stratification strategies for TNBC based on gene expression data: The first is focusing on the epithelial mesenchymal transition (EMT) and the second on the tumor immune microenvironment. Our results show that the two stratification strategies are not directly related, suggesting that the aggressiveness of the tumor can be due to a multitude of unrelated factors. In particular, the EMT stratification is able to identify a high-risk population with high immune markers that is, however, not properly classified by the tumor immune microenvironment based strategy.

Prognostic values of B7-H3, B7-H4, and HHLA2 expression in human pancreatic cancer tissues based on mIHC and spatial distribution analysis

BACKGROUND

Pancreatic cancer (PC) is one of the most malignant solid tumors and its 5-year survival rate remains poor. Although immunotherapy has achieved certain therapeutic efficacy in some clinical trials, such treatment still shows low responses and overall remission rate. Therefore, it is urgently necessary to dissect the tumor microenvironment and optimize the immunotherapeutic strategies against this malignancy.

METHODS

Using the multi-color immunohistochemistry assay, we investigated the expressions of B7-H3, B7-H4, HHLA2, CD8, and CD68 in 63 cases of PC tissues in a tissue microarray. Moreover, we analyzed immunolocalization features, clinical associations and prognostic values of these molecules.

RESULTS

The expressions of B7-H3, B7-H4, and HHLA2 could be detected in cytokeratin staining positive (CK+) cancer epithelial cells, CD68+tumor-associated macrophages (TAMs), and even other cells defined as CK-CD8-CD68-. Higher expression of B7-H3 in tumor cells could predict a better survival of the PC patients. A positive correlation was found between the expressions of B7-H3 and HHLA2 in tumor cells, while there was a negative correlation between the expressions of B7-H4 and HHLA2 in tumor cells. A positive correlation was found between the expressions of B7-H3 and B7-H4 or HHLA2 in CD68+TAMs, but not B7-H4 and HHLA2. Tumor-infiltrating CD8+T cells in combination with CD68+TAMs could serve as an important predictor for the postoperative prognosis of PC patients. Higher expression of B7-H3, or HHLA2 in CD68+TAMs could serve as an important predictor for poorer prognosis of PC patients. Patients with B7-H3lowB7-H4low, B7-H3lowHHLA2low, or B7-H4lowHHLA2low on CD68+TAMs could have a better postoperative prognosis compared with the other sub-populations in the combinational analysis.

CONCLUSIONS

Taken together, our study indicated variable expressions and prognostic values of B7-H3, B7-H4, and HHLA2, in human PC tissues, and demonstrated that these co-stimulator molecules expressed by CD68+TAMs could be used as important bio-markers for the prognostic prediction of PC patients. Moreover, these results supported that the evaluation of these markers could be used as essential candidate targets for immunotherapy against PC.

Expression of B7 family checkpoint proteins in cervical cancer

The role of programmed cell death-ligand 1 (PD-L1) in cervical cancer has been widely investigated; however, the influences of other inhibitory B7 family members are poorly understood. We investigated the expression of PD-L1, B7 homolog 3 (B7-H3), B7-H4, and V-domain Ig suppressor of T-cell activation (VISTA) and their association with the clinicopathological features and outcomes of a large cohort of 673 patients with squamous cell carcinoma or adenocarcinoma of the uterine cervix. The positivity rates for PD-L1 (combined positive score ≥1), B7-H3 in tumor cells (TCs), B7-H4 (exclusively in TCs), VISTA in immune cells (ICs), and VISTA in TCs were 57.9%, 62.8%, 44.8%, 92.6%, and 4.8%, respectively, in 606 primary cervical cancer samples. Co-expression of PD-L1 with B7-H3 in TCs and with B7-H4 and VISTA in ICs was observed in 38.8%, 25.4%, and 57.9% of samples, respectively. B7-H3 in TCs and B7-H4 and VISTA in ICs were observed in 58.1%, 46.6%, and 83.1% of PD-L1-negative samples, respectively. These proteins were observed more frequently in squamous cell carcinomas and in moderately to poorly differentiated carcinomas. VISTA (in ICs) and B7-H4 were more frequent in primary tumors than in recurrent counterparts and correlated with improved survival; in contrast, B7-H3 positivity in TCs was less frequent in primary tumors and correlated with short disease-specific survival. Co-expression of B7-H4 and VISTA in ICs was an independent predictor of favorable outcomes overall and among patients with PD-L1-negative tumors. These data indicate that B7 family proteins exhibit differing expression patterns, distributions, and prognostic implications in cervical cancer. Furthermore, the co-expression of PD-L1 with other checkpoint proteins suggests that PD-1/PD-L1 blockade combined with modulating other immune checkpoints may present a novel therapeutic approach for cervical cancer. Future studies are needed to validate prognostic values of B7 family proteins and explore their biological roles in this malignancy.

Immunosuppressive glycoproteins associate with breast tumor fibrosis and aggression

Tumors feature elevated sialoglycoprotein content. Sialoglycoproteins promote tumor progression and are linked to immune suppression via the sialic acid-Siglec axis. Understanding factors that increase sialoglycoprotein biosynthesis in tumors could identify approaches to improve patient response to immunotherapy. We quantified higher levels of sialoglycoproteins in the fibrotic regions within human breast tumor tissues. Human breast tumor subtypes, which are more fibrotic, similarly featured increased sialoglycoprotein content. Further analysis revealed the breast cancer cells as the primary cell type synthesizing and secreting the tumor tissue sialoglycoproteins and confirmed that the more aggressive, fibrotic breast cancer subtypes expressed the highest levels of sialoglycoprotein biosynthetic genes. The more aggressive breast cancer subtypes also featured greater infiltration of immunosuppressive SIGLEC7, SIGLEC9, and SIGLEC10-pos myeloid cells, indicating that triple-negative breast tumors had higher expression of both immunosuppressive Siglec receptors and their cognate ligands. The findings link sialoglycoprotein biosynthesis and secretion to tumor fibrosis and aggression in human breast tumors. The data suggest targeting of the sialic acid-Siglec axis may comprise an attractive therapeutic target particularly for the more aggressive HER2+ and triple-negative breast cancer subtypes.

Definitive study shows no association between ARID1A mutation status and clinical outcome in endometriosis related ovarian cancers

The ARID1A tumour suppressor protein is a component of the SWI/SNF chromatin remodelling complex, which is mutated in approximately 20% of all human cancers. ARID1A mutational status is considered to hold prognostic significance in a range of solid malignancies, yet in endometriosis‐related ovarian carcinomas there has been a lack of clarity of its prognostic role. Moreover, the relationship between ARID1A status and immune infiltrate is also poorly understood. In a recent issue of The Journal of Pathology, a large comprehensive study by Heinze, Nazeran et al addressed these areas by reviewing 1,623 endometriosis‐associated ovarian carcinomas and correlating ARID1A status using standardised immunohistochemistry to infer mutation status, with comprehensive clinicopathological features, mismatch repair status and CD8⁺ tumour infiltrating lymphocytes. The study definitively showed that ARID1A status does not provide any independent prognostic value in endometriosis‐associated ovarian carcinomas. ARID1A loss was, however, shown to be associated with mismatch repair deficiency and increased CD8⁺ tumour infiltrating lymphocytes in endometrioid ovarian carcinoma, which may be relevant for future studies. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

STING agonism reprograms tumor-associated macrophages and overcomes resistance to PARP inhibition in BRCA1-deficient models of breast cancer

PARP inhibitors (PARPi) have drastically changed the treatment landscape of advanced ovarian tumors with BRCA mutations. However, the impact of this class of inhibitors in patients with advanced BRCA-mutant breast cancer is relatively modest. Using a syngeneic genetically-engineered mouse model of breast tumor driven by Brca1 deficiency, we show that tumor-associated macrophages (TAMs) blunt PARPi efficacy both in vivo and in vitro. Mechanistically, BRCA1-deficient breast tumor cells induce pro-tumor polarization of TAMs, which in turn suppress PARPi-elicited DNA damage in tumor cells, leading to reduced production of dsDNA fragments and synthetic lethality, hence impairing STING-dependent anti-tumor immunity. STING agonists reprogram M2-like pro-tumor macrophages into an M1-like anti-tumor state in a macrophage STING-dependent manner. Systemic administration of a STING agonist breaches multiple layers of tumor cell-mediated suppression of immune cells, and synergizes with PARPi to suppress tumor growth. The therapeutic benefits of this combination require host STING and are mediated by a type I IFN response and CD8+ T cells, but do not rely on tumor cell-intrinsic STING. Our data illustrate the importance of targeting innate immune suppression to facilitate PARPi-mediated engagement of anti-tumor immunity in breast cancer.

Loss of RBMS1 promotes anti-tumor immunity through enabling PD-L1 checkpoint blockade in triple-negative breast cancer

Immunotherapy has been widely utilized in multiple tumors, however, its efficacy in the treatment of triple-negative breast cancers (TNBC) is still being challenged. Meanwhile, functions and mechanisms of RNA binding proteins in regulating immunotherapy for TNBC remain largely elusive. Here we reported that the RNA binding protein RBMS1 is prevalent among immune-cold TNBC. Through a systematic shRNA-mediated screen, we found depletion of RBMS1 significantly reduced the level of programmed death ligand 1 (PD-L1) in TNBC. Clinically, RBMS1 was increased in breast cancer and its level was positively correlated to that of PD-L1. RBMS1 ablation stimulated cytotoxic T cell mediated anti-tumor immunity. Mechanistically, RBMS1 regulated the mRNA stability of B4GALT1, a newly identified glycosyltransferase of PD-L1. Depletion of RBMS1 destabilized the mRNA of B4GALT1, inhibited the glycosylation of PD-L1 and promoted the ubiquitination and subsequent degradation of PD-L1. Importantly, combination of RBMS1 depletion with CTLA4 immune checkpoint blockade or CAR-T treatment enhanced anti-tumor T-cell immunity both in vitro and in vivo. Together, our findings provided a new immunotherapeutic strategy against TNBC by targeting the immunosuppressive RBMS1.

Narrative review of current status and recommendations in treatment for advanced triple-negative breast cancer

Background and Objective

The encouraging results of clinical trials for triple-negative breast cancer (TNBC) patients in recent years have gradually formed a system for the therapeutic regimen. As immunotherapy and precision therapy based on biomarkers have brought a new era to TNBC, it has become more crucial for clinicians to update the recommended treatment regimens for advanced TNBC patients.

Methods

We searched literatures related to the treatment for advanced TNBC from 2014 to 2022 on PubMed and sorted out them. In addition, the 2021-2022 guidelines in the part of treatment for advanced TNBC were downloaded on the official website of the guidelines referred to, which were summarized meanwhile.

Key Content and Findings

We summarized the current status of treatment for advanced TNBC from four aspects: immunotherapy, targeted therapy, antibody-drug conjugates (ADC) drug therapy and chemotherapy. The recommended therapeutic principles for the aspect of advanced TNBC in 2022 Chinese Society of Clinical Oncology (CSCO) guidelines were proposed in combination with international guidelines and conference recommendations.

Conclusions

It was emphasized that the detection and evaluation of biomarkers or targeting molecules should be the basis for choosing therapeutic regimens in this review and clinicians are supposed to accurately screen the population to achieve better treatment outcomes and prognosis for patients with advanced TNBC.

Reference-free cell type deconvolution of multi-cellular pixel-resolution spatially resolved transcriptomics data

Recent technological advancements have enabled spatially resolved transcriptomic profiling but at multi-cellular pixel resolution, thereby hindering the identification of cell-type-specific spatial patterns and gene expression variation. To address this challenge, we develop STdeconvolve as a reference-free approach to deconvolve underlying cell types comprising such multi-cellular pixel resolution spatial transcriptomics (ST) datasets. Using simulated as well as real ST datasets from diverse spatial transcriptomics technologies comprising a variety of spatial resolutions such as Spatial Transcriptomics, 10X Visium, DBiT-seq, and Slide-seq, we show that STdeconvolve can effectively recover cell-type transcriptional profiles and their proportional representation within pixels without reliance on external single-cell transcriptomics references. STdeconvolve provides comparable performance to existing reference-based methods when suitable single-cell references are available, as well as potentially superior performance when suitable single-cell references are not available. STdeconvolve is available as an open-source R software package with the source code available at https://github.com/JEFworks-Lab/STdeconvolve.

Identifying cell-type-specific spatial patterns in ST data is critical for understanding tissue organization but current methods rely on external references. Here the authors develop a reference-free method to effectively recover cell-type transcriptional profiles and proportions.

Spatial interplay of lymphocytes and fibroblasts in estrogen receptor-positive HER2-negative breast cancer

In estrogen-receptor-positive, HER2-negative (ER⁺HER2^-) breast cancer, higher levels of tumor infiltrating lymphocytes (TILs) are often associated with a poor prognosis and this phenomenon is still poorly understood. Fibroblasts represent one of the most frequent cells in breast cancer and harbor immunomodulatory capabilities. Here, we evaluate the molecular and clinical impact of the spatial patterns of TILs and fibroblast in ER⁺HER2^- breast cancer. We used a deep neural network to locate and identify tumor, TILs, and fibroblasts on hematoxylin and eosin-stained slides from 179 ER⁺HER2^- breast tumors (ICGC cohort) together with a new density estimation analysis to measure the spatial patterns. We clustered tumors based on their spatial patterns and gene set enrichment analysis was performed to study their molecular characteristics. We independently assessed the spatial patterns in a second cohort of ER⁺HER2^- breast cancer (N = 630, METABRIC) and studied their prognostic value. The spatial integration of fibroblasts, TILs, and tumor cells leads to a new reproducible spatial classification of ER⁺HER2^- breast cancer and is linked to inflammation, fibroblast meddling, or immunosuppression. ER⁺HER2^- patients with high TIL did not have a significant improved overall survival (HR = 0.76, P = 0.212), except when they had received chemotherapy (HR = 0.447). A poorer survival was observed for patients with high fibroblasts that did not show a high level of TILs (HR = 1.661, P = 0.0303). Especially spatial mixing of fibroblasts and TILs was associated with a good prognosis (HR = 0.464, P = 0.013). Our findings demonstrate a reproducible pipeline for the spatial profiling of TILs and fibroblasts in ER⁺HER2^- breast cancer and suggest that this spatial interplay holds a decisive role in their cancer-immune interactions.

Extracellular vesicles from triple negative breast cancer promote pro-inflammatory macrophages associated with better clinical outcome

Our work uncovers mechanisms by which tumor cells impact tumor-associated macrophages in human triple-negative breast cancer. Via extracellular vesicles (EVs), these tumors promote macrophages with proinflammatory features, correlated with better clinical outcome. Our results suggest exploration of these EVs as tools, alone, or in combination with other therapies, to promote a favorable environment for the generation of anti-tumor immune responses.

Tumor associated macrophages (TAMs), which differentiate from circulating monocytes, are pervasive across human cancers and comprise heterogeneous populations. The contribution of tumor-derived signals to TAM heterogeneity is not well understood. In particular, tumors release both soluble factors and extracellular vesicles (EVs), whose respective impact on TAM precursors may be different. Here, we show that triple negative breast cancer cells (TNBCs) release EVs and soluble molecules promoting monocyte differentiation toward distinct macrophage fates. EVs specifically promoted proinflammatory macrophages bearing an interferon response signature. The combination in TNBC EVs of surface CSF-1 promoting survival and cargoes promoting cGAS/STING or other activation pathways led to differentiation of this particular macrophage subset. Notably, macrophages expressing the EV-induced signature were found among patients’ TAMs. Furthermore, higher expression of this signature was associated with T cell infiltration and extended patient survival. Together, this data indicates that TNBC-released CSF-1-bearing EVs promote a tumor immune microenvironment associated with a better prognosis in TNBC patients.

Multifunctional Lipid Bilayer Nanocarriers for Cancer Immunotherapy in Heterogeneous Tumor Microenvironments, Combining Immunogenic Cell Death Stimuli with Immune Modulatory Drugs

In addition to the contribution of cancer cells, the solid tumor microenvironment (TME) has a critical role in determining tumor expansion, antitumor immunity, and the response to immunotherapy. Understanding the details of the complex interplay between cancer cells and components of the TME provides an unprecedented opportunity to explore combination therapy for intervening in the immune landscape to improve immunotherapy outcome. One approach is the introduction of multifunctional nanocarriers, capable of delivering drug combinations that provide immunogenic stimuli for improvement of tumor antigen presentation, contemporaneous with the delivery of coformulated drug or synthetic molecules that provide immune danger signals or interfere in immune-escape, immune-suppressive, and T-cell exclusion pathways. This forward-looking review will discuss the use of lipid-bilayer-encapsulated liposomes and mesoporous silica nanoparticles for combination immunotherapy of the heterogeneous immune landscapes in pancreatic ductal adenocarcinoma and triple-negative breast cancer. We describe how the combination of remote drug loading and lipid bilayer encapsulation is used for the synthesis of synergistic drug combinations that induce immunogenic cell death, interfere in the PD-1/PD-L1 axis, inhibit the indoleamine-pyrrole 2,3-dioxygenase (IDO-1) immune metabolic pathway, restore spatial access to activated T-cells to the cancer site, or reduce the impact of immunosuppressive stromal components. We show how an integration of current knowledge and future discovery can be used for a rational approach to nanoenabled cancer immunotherapy.

Immunogenic Cell Death-Relevant Damage-Associated Molecular Patterns and Sensing Receptors in Triple-Negative Breast Cancer Molecular Subtypes and Implications for Immunotherapy

Objectives

Triple-negative breast cancer (TNBC) is defined as a highly aggressive type of breast cancer which lacks specific biomarkers and drug targets. Damage-associated molecular pattern (DAMP)-induced immunogenic cell death (ICD) may influence the outcome of immunotherapy for TNBC patients. This study aims to develop a DAMPs gene signature to classify TNBC patients and to further predict their prognosis and immunotherapy outcome.

Methods

We identified the DAMPs-associated subtypes of 330 TNBCs using K-means analysis. Differences in immune status, genomic alterations, and predicted immunotherapy outcome were compared among each subtype.

Results

A total of 330 TNBCs were divided into three subtypes according to DAMPs gene expression: the nuclear DAMPs subtype, featuring the upregulation of nuclear DAMPs; the inflammatory DAMPs subtype, characterized by the gene set enrichment of the adaptive immune system and cytokine signaling in the immune system; and the DAMPs-suppressed subtype, having the lowest level of ICD-associated DAMPs. Among them, the inflammatory subtype patients had the most favorable survival, while the DAMPs-suppressed subtype was associated with the worst prognosis. The DAMPs subtyping system was successfully validated in the TCGA cohort. Furthermore, we systemically revealed the genomic alterations among the three DAMPs subtypes. The inflammatory DAMPs subtype was predicted to have the highest response rate to immunotherapy, suggesting that the constructed DAMPs clustering had potential for immunotherapy efficacy prediction.

Conclusion

We established a novel ICD-associated DAMPs subtyping system in TNBC, and DAMPs expression might be a valuable biomarker for immunotherapy strategies. Our work could be helpful to the development of new immunomodulators and may contribute to the development of precision immunotherapy for TNBC.

The Transcriptomic Portrait of Locally Advanced Breast Cancer and Its Prognostic Value in a Multi-Country Cohort of Latin American Patients

Purposes

Most molecular-based published studies on breast cancer do not adequately represent the unique and diverse genetic admixture of the Latin American population. Searching for similarities and differences in molecular pathways associated with these tumors and evaluating its impact on prognosis may help to select better therapeutic approaches.

Patients and Methods

We collected clinical, pathological, and transcriptomic data of a multi-country Latin American cohort of 1,071 stage II-III breast cancer patients of the Molecular Profile of Breast Cancer Study (MPBCS) cohort. The 5-year prognostic ability of intrinsic (transcriptomic-based) PAM50 and immunohistochemical classifications, both at the cancer-specific (OSC) and disease-free survival (DFS) stages, was compared. Pathway analyses (GSEA, GSVA and MetaCore) were performed to explore differences among intrinsic subtypes.

Results

PAM50 classification of the MPBCS cohort defined 42·6% of tumors as LumA, 21·3% as LumB, 13·3% as HER2E and 16·6% as Basal. Both OSC and DFS for LumA tumors were significantly better than for other subtypes, while Basal tumors had the worst prognosis. While the prognostic power of traditional subtypes calculated with hormone receptors (HR), HER2 and Ki67 determinations showed an acceptable performance, PAM50-derived risk of recurrence best discriminated low, intermediate and high-risk groups. Transcriptomic pathway analysis showed high proliferation (i.e. cell cycle control and DNA damage repair) associated with LumB, HER2E and Basal tumors, and a strong dependency on the estrogen pathway for LumA. Terms related to both innate and adaptive immune responses were seen predominantly upregulated in Basal tumors, and, to a lesser extent, in HER2E, with respect to LumA and B tumors.

Conclusions

This is the first study that assesses molecular features at the transcriptomic level in a multicountry Latin American breast cancer patient cohort. Hormone-related and proliferation pathways that predominate in PAM50 and other breast cancer molecular classifications are also the main tumor-driving mechanisms in this cohort and have prognostic power. The immune-related features seen in the most aggressive subtypes may pave the way for therapeutic approaches not yet disseminated in Latin America.

Clinical Trial Registration

ClinicalTrials.gov (Identifier: NCT02326857).

Dissecting Tumor-Immune Microenvironment in Breast Cancer at a Spatial and Multiplex Resolution

The tumor immune microenvironment (TIME) is an important player in breast cancer pathophysiology. Surrogates for antitumor immune response have been explored as predictive biomarkers to immunotherapy, though with several limitations. Immunohistochemistry for programmed death ligand 1 suffers from analytical problems, immune signatures are devoid of spatial information and histopathological evaluation of tumor infiltrating lymphocytes exhibits interobserver variability. Towards improved understanding of the complex interactions in TIME, several emerging multiplex in situ methods are being developed and gaining much attention for protein detection. They enable the simultaneous evaluation of multiple targets in situ, detection of cell densities/subpopulations as well as estimations of functional states of immune infiltrate. Furthermore, they can characterize spatial organization of TIME—by cell-to-cell interaction analyses and the evaluation of distribution within different regions of interest and tissue compartments—while digital imaging and image analysis software allow for reproducibility of the various assays. In this review, we aim to provide an overview of the different multiplex in situ methods used in cancer research with special focus on breast cancer TIME at the neoadjuvant, adjuvant and metastatic setting. Spatial heterogeneity of TIME and importance of longitudinal evaluation of TIME changes under the pressure of therapy and metastatic progression are also addressed.

Investigating the Prognostic Relevance of Tumor Immune Microenvironment and Immune Gene Assembly in Breast Carcinoma Subtypes

We hypothesized that different BC subtypes are characterized by spatially distinct tumor immune microenvironment (TIME) and that immune gene assembly of metastatic (Met) and non-metastatic (Ctrl) BCs vary across subtypes. Peritumoral, stromal and intratumoral TIL was assessed on 309 BC cases. Hot, cold and immune-excluded groups were defined, and the prognostic role of this classification was assessed. CD4+/CD8+ positivity was analyzed in 75 cases in four systematically predefined tumor regions. Immune gene expression of Met and Ctrl HER2-negative BCs was compared by using NanoString nCounter technology. The amount of TIL infiltration varied greatly within all BC subtypes. Two-third of the cases were cold tumors with no significant survival difference compared to hot tumors. A lower CD4+/CD8+ ratio at the stromal internal tumor region was significantly associated with longer distant metastasis-free survival. The differentially expressed immune genes between Met and Ctrl varied across the studied BC subtypes with TNBC showing distinct features from the luminal subtypes. The TIME is characterized by a considerable heterogeneity; however, low level of TILs does not equate to disease progression. The differences in immune gene expression observed between Met and Ctrl breast carcinomas call attention to the important role of altered immune function in BC progression.

Spatially mapping the immune landscape of melanoma using imaging mass cytometry

Melanoma is an immunogenic cancer with a high response rate to immune checkpoint inhibitors (ICIs). It harbors a high mutation burden compared with other cancers and, as a result, has abundant tumor-infiltrating lymphocytes (TILs) within its microenvironment. However, understanding the complex interplay between the stroma, tumor cells, and distinct TIL subsets remains a substantial challenge in immune oncology. To properly study this interplay, quantifying spatial relationships of multiple cell types within the tumor microenvironment is crucial. To address this, we used cytometry time-of-flight (CyTOF) imaging mass cytometry (IMC) to simultaneously quantify the expression of 35 protein markers, characterizing the microenvironment of 5 benign nevi and 67 melanomas. We profiled more than 220,000 individual cells to identify melanoma, lymphocyte subsets, macrophage/monocyte, and stromal cell populations, allowing for in-depth spatial quantification of the melanoma microenvironment. We found that within pretreatment melanomas, the abundance of proliferating antigen-experienced cytotoxic T cells (CD8⁺CD45RO⁺Ki67⁺) and the proximity of antigen-experienced cytotoxic T cells to melanoma cells were associated with positive response to ICIs. Our study highlights the potential of multiplexed single-cell technology to quantify spatial cell-cell interactions within the tumor microenvironment to understand immune therapy responses.

Comparison of the Clinicopathologic Features and T-Cell Infiltration of B7-H3 and B7-H4 Expression in Triple-negative Breast Cancer Subtypes

Previously we revealed an upregulated expression of B7-H3 and B7-H4 mRNA and protein in breast cancer, including triple-negative breast cancer (TNBC). However, little is known regarding the clinical impact and value of B7-H3 and B7-H4 in TNBC subtypes. Thus, this study evaluated the clinicopathologic effects of B7-H3 and B7-H4 mRNA and protein expression according to the TNBC subtypes. RNAscope in situ hybridization and immunohistochemistry of B7-H3 and B7-H4 was done for 186 TNBC samples using tissue microarray. Immunohistochemistry was also performed for TNBC molecular subtype-surrogate markers, CD3, and CD8. TNBCs were classified into basal-like (BL) (64.5%), luminal androgen receptor (10.8%), and unclassifiable (24.7%) subtypes. Tumor B7-H4 mRNA expression was associated with younger age at the initial diagnosis and with molecular TNBC subtypes. Expression of B7-H3 mRNA and protein in the tumor cells was negatively correlated with CD3+ and CD8+ T-cell infiltration density in the tumor and/or stromal region of TNBCs and their subtypes. High stromal B7-H3 mRNA expression was associated with poor disease-free and overall survival in the TNBCs and with overall survival in the unclassifiable subtype. Stromal B7-H3 mRNA expression was independently associated with overall survival and disease-free survival in the TNBCs and BL subtype, respectively. Our results indicate the importance of the stromal expression of B7-H3 mRNA as a prognostic factor in the TNBCs and BL subtype. The inverse relationship between B7-H3 expression and CD3+ and CD8+ T-lymphocyte infiltration represents a promising target for immunotherapy for the TNBCs, especially the BL subtype.

Integrated analysis reveals the molecular features of fibrosis in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer. High fibrosis, marked by increased collagen fibers, is widespread in TNBC and correlated with tumor progression. However, the molecular features of fibrosis and why it results in a poor prognosis remain poorly understood. Based on multiomics datasets of TNBC, we evaluated the pathological fibrosis grade of 344 samples for further analysis. Genomic, transcriptomic, and immune changes were analyzed among different subgroups of fibrosis. High fibrosis was an independent adverse prognosis predictor and had interactions with low stromal tumor-infiltrating lymphocytes. Genomic analysis identified copy number gains of 6p22.2–6p22.1 (TRIM27) and 20q13.33 (CDH4) as genomic hallmarks of tumors with high fibrosis. Transcriptome analysis revealed the transforming growth factor-beta pathway and hypoxia pathway were key pro-oncogenic pathways in tumors with high fibrosis. Moreover, we systematically evaluate the relationship between fibrosis and different kinds of immune and stromal cells. Tumors with high fibrosis were characterized by an immunosuppressive tumor microenvironment with limited immune cell infiltration and increased fibroblasts. This study proposes new insight into the genomic and transcriptomic alterations potentially driving fibrosis. Moreover, fibrosis is related to an immunosuppressive tumor microenvironment that contributes to the poor prognosis.

Ephrin receptor A10 monoclonal antibodies and the derived chimeric antigen receptor T cells exert an antitumor response in mouse models of triple-negative breast cancer

Expression of the receptor tyrosine kinase ephrin receptor A10 (EphA10), which is undetectable in most normal tissues except for the male testis, has been shown to correlate with tumor progression and poor prognosis in several malignancies, including triple-negative breast cancer (TNBC). Therefore, EphA10 could be a potential therapeutic target, likely with minimal adverse effects. However, no effective clinical drugs against EphA10 are currently available. Here, we report high expression levels of EphA10 in tumor regions of breast, lung, and ovarian cancers as well as in immunosuppressive myeloid cells in the tumor microenvironment. Furthermore, we developed anti-EphA10 monoclonal antibodies (mAbs) that specifically recognize cell surface EphA10, but not other EphA family isoforms, and target tumor regions precisely in vivo with no apparent accumulation in other organs. In syngeneic TNBC mouse models, we found that anti-EphA10 mAb clone #4 enhanced tumor regression, therapeutic response rate, and T cell–mediated antitumor immunity. Notably, the chimeric antigen receptor T cells derived from clone #4 significantly inhibited TNBC cell viability in vitro and tumor growth in vivo. Together, our findings suggest that targeting EphA10 via EphA10 mAbs and EphA10-specific chimeric antigen receptor–T cell therapy may represent a promising strategy for patients with EphA10-positive tumors.

Integrative Analysis of a Pyroptosis-Related Signature of Clinical and Biological Value in Multiple Myeloma

Purpose

Pyroptosis is an inflammation-based programmed cell death that holds great potential as a novel cancer therapeutic target in patients with multiple myeloma (MM). However, thus far, the function of pyroptosis-related genes (PRGs) in MM and their prognostic relevance remains undetermined.

Methods

The model was established by the LASSO analysis, based on the Gene Expression Omnibus (GEO) dabatase, and its efficacy was verified using two external datasets. The model’s predictive ability was assessed by the Kaplan-Meier survival and time-dependent receiver operating characteristic (ROC) curves. Finally, a nomogram was established for clinical application. We also confirmed the validity of our model using specimens and in vitro experiments.

Results

We established an 11-PRG signature profile, and verified its efficacy using two validation cohorts (VCs). In both cohorts, patients were separated into two subpopulations, according to their median risk scores (RS). Our analysis revealed that high-risk (HR) patients experienced considerably lower overall survival (OS), compared to the low-risk (LR) patients. Using functional enrichment and immune infiltration analyses, we demonstrated that the immunologic status was strongly related to RS. Furthermore, using a pyroptosis inhibitor Q-VD-OPh, we revealed that MM cell proliferation and progression was drastically suppressed and the doxorubicin (DOX)-induced apoptosis was reversed.

Conclusion

Based on our analysis, pyroptosis not only serves as a measure of MM treatment efficiency and patient prognosis, but is also a possible target for anti-MM therapy.

New insights into the discovery of drugs for triple-negative breast cancer metastasis

INTRODUCTION

Triple-negative breast cancer (TNBC) is of great concern due to its aggressiveness and lack of targeted therapy. For these reasons, TNBC is one of the main causes of death in women, mainly due to metastases. Tumor dissemination has highlighted a set of possible targets, with extensive research into new single-target drugs, in addition to drug repurposing strategies, being undertaken to discover new classes of potential inhibitors of metastasis.

AREAS COVERED

The authors here describe the main proposed targets and the bases of their pharmacological inhibition with different chemical compounds. The authors also discuss the state-of-the-art from the latest clinical trials and highlight other potential targets for metastatic TNBC.

EXPERT OPINION

In the last decade, oncology research has changed its focus from primary tumors to moving tumor cells, their products, and to the secondary tumor and its surroundings, for the purpose of finding targets to treat metastasis. Consequently, our comprehension of the complexity of the metastatic process has increased drastically, with, furthermore, the discovery of new potential targets. Although promising, the wide range of strategies is still not effective to suppress TNBC metastasis in terms of increasing patient survival or decreasing the number of metastases. Treating or preventing metastasis continues to be a great challenge.

Preclinical PET Imaging of Granzyme B Shows Promotion of Immunological Response Following Combination Paclitaxel and Immune Checkpoint Inhibition in Triple Negative Breast Cancer

Advancements in monitoring and predicting of patient-specific response of triple negative breast cancer (TNBC) to immunotherapy (IMT) with and without chemotherapy are needed. Using granzyme B-specific positron emission tomography (GZP-PET) imaging, we aimed to monitor changes in effector cell activation in response to IMT with chemotherapy in TNBC. TNBC mouse models received the paclitaxel (PTX) ± immune checkpoint inhibitors anti-programmed death 1 (anti-PD1) and anti-cytotoxic T-lymphocyte 4 (anti-CTLA4). GZP-PET imaging was performed on treatment days 0, 3, and 6. Mean standard uptake value (SUVmean), effector cell fractions, and SUV histograms were compared. Mice were sacrificed at early imaging timepoints for cytokine and histological analyses. GZP-PET imaging data revealed differences prior to tumor volume changes. By day six, responders had SUVmean ≥ 2.2-fold higher (p < 0.0037) and effector cell fractions ≥ 1.9-fold higher (p = 0.03) compared to non-responders. IMT/PTX resulted in a significantly different SUV distribution compared to control, indicating broader distribution of activated intratumoral T-cells. IMT/PTX resulted in significantly more necrotic tumor tissue and increased levels of IL-2, 4, and 12 compared to control. Results implicate immunogenic cell death through upregulation of key Th1/Th2 cytokines by IMT/PTX. Noninvasive PET imaging can provide data on the TNBC tumor microenvironment, specifically intratumoral effector cell activation, predicting response to IMT plus chemotherapy.

Tumor-infiltrating exhausted CD8+ T cells dictate reduced survival in premenopausal estrogen receptor-positive breast cancer

CD8⁺ tumor-infiltrating lymphocytes (TILs) are associated with improved survival in triple-negative breast cancer (TNBC) yet have no association with survival in estrogen receptor–positive (ER⁺) BC. The basis for these contrasting findings remains elusive. We identified subsets of BC tumors infiltrated by CD8⁺ T cells with characteristic features of exhausted T cells (T_EX). Tumors with abundant CD8⁺ T_EX exhibited a distinct tumor microenvironment marked by amplified interferon-γ signaling–related pathways and higher programmed death ligand 1 expression. Paradoxically, higher levels of tumor-infiltrating CD8⁺ T_EX associated with decreased overall survival of patients with ER⁺ BC but not patients with TNBC. Moreover, high tumor expression of a CD8⁺ T_EX signature identified dramatically reduced survival in premenopausal, but not postmenopausal, patients with ER⁺ BC. Finally, we demonstrated the value of a tumor T_EX signature score in identifying high-risk premenopausal ER⁺ BC patients among those with intermediate Oncotype DX Breast Recurrence Scores. Our data highlight the complex relationship between CD8⁺ TILs, interferon-γ signaling, and ER status in BC patient survival. This work identifies tumor-infiltrating CD8⁺ T_EX as a key feature of reduced survival outcomes in premenopausal patients with early-stage ER⁺ BC.

Prospects of Immunotherapy for Triple-Negative Breast Cancer

In the classification and typing of breast cancer, triple-negative breast cancer (TNBC) is one type of refractory breast cancer, while chemotherapy stays in the traditional treatment methods. However, the impact of chemotherapy is short-lived and may lead to recurrence due to incomplete killing of tumor cells. The occurrence, development, and relapse of breast cancer are relevant to T cell dysfunction, multiplied expression of related immune checkpoint molecules (ICIs) such as programmed death receptor 1 (PD-1), programmed cell death 1 ligand 1 (PD-L1), and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) produce immunosuppressive effect. Immunotherapy (namely, immune checkpoint inhibitors, adoptive cellular immunotherapy, CAR-T immunotherapy and some potential treatments) provides new hope in TNBC. This review focuses on the new immune strategies of TNBC patients.

Innate Immunity and Cancer Pathophysiology

Chronic inflammation increases the risk of several cancers, including gastric, colon, and hepatic cancers. Conversely, tumors, similar to tissue injury, trigger an inflammatory response coordinated by the innate immune system. Cellular and molecular mediators of inflammation modulate tumor growth directly and by influencing the adaptive immune response. Depending on the balance of immune cell types and signals within the tumor microenvironment, inflammation can support or restrain the tumor. Adding to the complexity, research from the past two decades has revealed that innate immune cells are highly heterogeneous and plastic, with variable phenotypes depending on tumor type, stage, and treatment. The field is now on the cusp of being able to harness this wealth of data to (a) classify tumors on the basis of their immune makeup, with implications for prognosis, treatment choice, and clinical outcome, and (b) design therapeutic strategies that activate antitumor immune responses by targeting innate immune cells.

Pathogenesis of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) encompasses a heterogeneous group of fundamentally different diseases with different histologic, genomic, and immunologic profiles, which are aggregated under this term because of their lack of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 expression. Massively parallel sequencing and other omics technologies have demonstrated the level of heterogeneity in TNBCs and shed light into the pathogenesis of this therapeutically challenging entity in breast cancer. In this review, we discuss the histologic and molecular classifications of TNBC, the genomic alterations these different tumor types harbor, and the potential impact of these alterations on the pathogenesis of these tumors. We also explore the role of the tumor microenvironment in the biology of TNBCs and its potential impact on therapeutic response. Dissecting the biology and understanding the therapeutic dependencies of each TNBC subtype will be essential to delivering on the promise of precision medicine for patients with triple-negative disease.

De-glycosylated membrane PD-L1 in tumor tissues as a biomarker for responsiveness to atezolizumab (Tecentriq) in advanced breast cancer patients

The atezolizumab (Tecentriq), a humanized antibody against human programmed death ligand 1 (PD-L1), combined with nab-paclitaxel was granted with accelerated approval to treat unresectable locally advanced or metastatic triple-negative breast cancer (TNBC) due to the encouraging positive results of the phase 3 IMpassion130 trial using PD-L1 biomarker from immune cells to stratify patients. However, the post-market study IMpassion131 did not support the original observation, resulting in the voluntary withdrawal of atezolizumab from the indication in breast cancer by Genentech in 2021. Emerging evidence has revealed a high frequency of false negative result using the standard immunohistochemical (IHC) staining due to heavy glycosylation of PD-L1. The removal of glycosylation prevents from the false negative staining, enabling more accurate assessment of PD-L1 levels and improving prediction for response to immune checkpoint therapy. In the present study, the natural and de-glycosylated PD-L1 expression in tumor and immune cells from nine TNBC patients were analyzed by using clone 28-8 monoclonal antibody to correlate with treatment outcome. Our results demonstrate that: (1) Removal of the glycosylation indeed enhances the detection of PD-L1 by IHC staining, (2) The PD-L1 levels on tumor cell surface after removal of the glycosylation correlates well with clinical responses for atezolizumab treatment; (3) The criteria used in the IMpassion130 and IMpassion131 trials which scored the natural PD-L1 in the immune cells failed to correlate with the clinical response. Taken together, tumor cell surface staining of PD-L1 with de-glycosylation has a significant correlation with the clinical response for atezolizumab treatment, suggesting that treatment of atezolizumab may be worthy of further consideration with de-glycosylation procedure as a patient stratification strategy. A larger cohort to validate this important issue is warranted to ensure right patient population who could benefit from the existing FDA-approved drugs.

Landscape of cancer-associated fibroblasts identifies the secreted biglycan as a protumor and immunosuppressive factor in triple-negative breast cancer

Cancer-associated fibroblasts (CAFs) are essential for tumor microenvironment remodeling and correlate with tumor progression. However, interactions between CAFs and tumor cells and immune cells in triple-negative breast cancer (TNBC) are still poorly explored. Here, we investigate the role of CAFs in TNBC and potential novel mediators of their functions. The clustering of classic markers was applied to estimate the relative abundance of CAFs in TNBC cohorts. Primary fibroblasts were isolated from normal and tumor samples. The RNA and culture medium of fibroblasts were subjected to RNA sequencing and mass spectrometry to explore the upregulated signatures in CAFs. Microdissection and single-cell RNA sequencing datasets were used to examine the expression profiles. CAFs were associated with hallmark signalings and immune components in TNBC. Clustering based on CAF markers in the literature revealed different CAF infiltration groups in TNBC: low, medium and high. Most of the cancer hallmark signaling pathways were enriched in the high CAF infiltration group. Furthermore, RNA sequencing and mass spectrometry identified biglycan (BGN), a soluble secreted protein, as upregulated in CAFs compared to normal cancer-adjacent fibroblasts (NAFs). The expression of biglycan was negatively correlated with CD8 + T cells. Biglycan indicated poor prognostic outcomes and might be correlated with the immunosuppressive tumor microenvironment (TME). In conclusion, CAFs play an essential role in tumor progression and the TME. We identified an extracellular protein, biglycan, as a prognostic marker and potential therapeutic target in TNBC.

Spatial Profiling Identifies Prognostic Features of Response to Adjuvant Therapy in Triple Negative Breast Cancer (TNBC)

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that has few effective treatment options due to its lack of targetable hormone receptors. Whilst the degree of tumour infiltrating lymphocytes (TILs) has been shown to associate with therapy response and prognosis, deeper characterization of the molecular diversity that may mediate chemotherapeutic response is lacking. Here we applied targeted proteomic analysis of both chemotherapy sensitive and resistant TNBC tissue samples by the Nanostring GeoMx Digital Spatial Platform (DSP). By quantifying 68 targets in the tumour and tumour microenvironment (TME) compartments and performing differential expression analysis between responsive and non-responsive tumours, we show that increased ER-alpha expression and decreased 4-1BB and MART1 within the stromal compartments is associated with adjuvant chemotherapy response. Similarly, higher expression of GZMA, STING and fibronectin and lower levels of CD80 were associated with response within tumour compartments. Univariate overall-survival (OS) analysis of stromal proteins supported these findings, with ER-alpha expression (HR=0.19, p=0.0012) associated with better OS while MART1 expression (HR=2.3, p=0.035) was indicative of poorer OS. Proteins within tumour compartments consistent with longer OS included PD-L1 (HR=0.53, p=0.023), FOXP3 (HR=0.5, p=0.026), GITR (HR=0.51, p=0.036), SMA (HR=0.59, p=0.043), while EPCAM (HR=1.7, p=0.045), and CD95 (HR=4.9, p=0.046) expression were associated with shorter OS. Our data provides early insights into the levels of these markers in the TNBC tumour microenvironment, and their association with chemotherapeutic response and patient survival.

The B7H4-PDL1 classifier stratifies immuno-phenotype in cervical cancer

BACKGROUND

It has been revealed that B7H4 is negatively correlated with PDL1 and identifies immuno-cold tumors in glioma. However, the application of the B7H4-PDL1 classifier in cancers has not been well testified.

METHODS

A pan-cancer analysis was conducted to evaluate the immunological role of B7H4 using the RNA-sequencing data downloaded from the Cancer Genome Atlas (TCGA). Immunohistochemistry (IHC) and multiplexed quantitative immunofluorescence (QIF) were performed to validate the primary results revealed by bioinformatics analysis.

RESULTS

The pan-cancer analysis revealed that B7H4 was negatively correlated with PDL1 expression and immune cell infiltration in CeCa. In addition, patients with high B7H4 exhibited the shortest overall survival (OS) and relapse-free survival (RFS) while those with high PDL1 exhibited a better prognosis. Multiplexed QIF showed that B7H4 was mutually exclusive with PDL1 expression and the B7H4-high group exhibited the lowest CD8 + T cell infiltration. Besides, B7H4-high predicted highly proliferative subtypes, which expressed the highest Ki67 antigen. Moreover, B7H4-high also indicated a lower response to multiple therapies.

CONCLUSIONS

Totally, the B7H4-PDL1 classifier identifies the immunogenicity and predicts proliferative subtypes and limited therapeutic options in CeCa, which may be a convenient and feasible biomarker in clinical practice.

Protein phosphatase 1 regulatory inhibitor subunit 14C promotes triple-negative breast cancer progression via sustaining inactive glycogen synthase kinase 3 beta

Triple-negative breast cancer (TNBC) is fast-growing and highly metastatic with the poorest prognosis among the breast cancer subtypes. Inactivation of glycogen synthase kinase 3 beta (GSK3β) plays a vital role in the aggressiveness of TNBC; however, the underlying mechanism for sustained GSK3β inhibition remains largely unknown. Here, we find that protein phosphatase 1 regulatory inhibitor subunit 14C (PPP1R14C) is upregulated in TNBC and relevant to poor prognosis in patients. Overexpression of PPP1R14C facilitates cell proliferation and the aggressive phenotype of TNBC cells, whereas the depletion of PPP1R14C elicits opposite effects. Moreover, PPP1R14C is phosphorylated and activated by protein kinase C iota (PRKCI) at Thr73. p-PPP1R14C then represses Ser/Thr protein phosphatase type 1 (PP1) to retain GSK3β phosphorylation at high levels. Furthermore, p-PPP1R14C recruits E3 ligase, TRIM25, toward the ubiquitylation and degradation of non-phosphorylated GSK3β. Importantly, the blockade of PPP1R14C phosphorylation inhibits xenograft tumorigenesis and lung metastasis of TNBC cells. These findings provide a novel mechanism for sustained GSK3β inactivation in TNBC and suggest that PPP1R14C might be a potential therapeutic target.