Immune System Effects on Breast Cancer

Use and Comparison of Machine Learning Techniques to Discern the Protein Patterns of Autoantibodies Present in Women with and without Breast Pathology

Breast cancer (BC) has become a global health problem, ranking first in incidence and fifth in mortality in women around the world. Although there are some diagnostic methods for the disease, these are not sufficiently effective and are invasive. In this work, we discriminated between patients without breast pathology (BP), with benign BP, and with BC based on the band patterns obtained from Western blot strip images of the autoantibody response to antigens of the T47D tumor line using and comparing supervised machine learning techniques to have a sensitive and accurate method. When comparing the aforementioned machine learning techniques, it was found that by obtaining a convolutional neural network architecture from a neuroevolution algorithm, it is possible to automatically discriminate with a classification accuracy of 90.67% between patients with cancer and with/without BP. In the case of discrimination between patients with cancer and without BP, a classification accuracy of 96.67% was obtained with the K-NN algorithm and 95.13% with the convolutional neural network obtained using a neuroevolution algorithm, although these results are not statistically significant. It is concluded that the convolutional neural network obtained by neuroevolution is the method with the best performance with respect to those evaluated in this work.

Midkine as a driver of age-related changes and increase in mammary tumorigenesis

Aging is a pivotal risk factor for cancer, yet the underlying mechanisms remain poorly defined. Here, we explore age-related changes in the rat mammary gland by single-cell multiomics. Our findings include increased epithelial proliferation, loss of luminal identity, and decreased naive B and T cells with age. We discover a luminal progenitor population unique to old rats with profiles reflecting precancerous changes and identify midkine (Mdk) as a gene upregulated with age and a regulator of age-related luminal progenitors. Midkine treatment of young rats mimics age-related changes via activating PI3K-AKT-SREBF1 pathway and promotes nitroso-N-methylurea-induced mammary tumorigenesis. Midkine levels increase with age in human blood and mammary epithelium, and higher MDK in normal breast tissue is associated with higher breast cancer risk in younger women. Our findings reveal a link between aging and susceptibility to tumor initiation and identify midkine as a mediator of age-dependent increase in breast tumorigenesis.

Breast cancer immunotherapy: Realities and advances

Breast cancer (BC) is the most common malignant tumor and the main cause of death in women worldwide. With increased knowledge regarding tumor escape mechanisms and advances in immunology, many new antitumor strategies such as nonspecific immunotherapies, monoclonal antibodies, anticancer vaccines, and oncolytic viruses, among others, make immunotherapy a promising approach for the treatment of BC. However, these approaches still require meticulous assessment and readjustment as resistance and modest response rates remain important barriers. In this article, we aim to summarize the most recent data available in BC immunotherapy to include the results of ongoing clinical trials and approved therapies used as monotherapies or in combination with conventional treatments.

Genetically predicted Caspase 8 levels mediates the causal association between CD4+ T cell and breast cancer

Background

Breast cancer (BC) remains a significant contributor to female mortality globally, with inflammation and the immune system implicated in its pathogenesis. To elucidate potential causal relationships, we evaluated the relationship among 731 immune cell phenotypes and BC be at risk by using Mendelian randomization (MR), while also exploring inflammatory proteins as mediators in this association.

Methods

We obtained immune cell genome-wide association study (GWAS) summary data and 91 inflammatory factors from the GWAS Catalog. BC GWAS data was obtained from the IEU Open GWAS project (ukb-b-16890 for discovery and GCST004988 for validation). We investigated the causal link between immune cells and BC risk by employing a two-sample MR method. Furthermore, we use a two-step MR to quantify the percentage of mediation of immune cell-BC causal effects mediated by inflammatory proteins. To make sure the causal findings were robust, a sensitivity analysis was done.

Results

In both discovery and validation GWAS, a critical inverse correlation between CD4+ T cells and BC risk was found using MR analysis (Discovery: OR, 0.996; P = 0.030. Validation: OR, 0.843; P = 4.09E-07) with Caspase 8 levels mediating 18.9% of the reduced BC risk associated with immune cells(Mediation proportion=a×b/c, Discovery:0.151×-0.005/-0.004 = 18.9%; Validation:0.151×-0.214/-0.171 = 18.9%).

Conclusion

Our study establishes a causal connection linking CD4+ T cells and BC, with Caspase 8 levels partially mediating this relationship. These findings enhance our genetic and molecular comprehension of BC, suggesting potential pathways for future BC immunotherapy drug development.

Evaluation of immunophenotype and inflammation in canine mammary neoplasms with solid arrangement

Morphological and immunohistochemical studies of solid arrangement canine mammary carcinomas have shown that the different histological types may be characterized by proliferation of epithelial and/or myoepithelial cells. However, little is known about immunophenotypes and the importance of inflammation as prognostic factors in these neoplasms. The objective of the present study was to characterize the immunophenotype and degree of inflammation in the solid type of canine mammary neoplasm and to investigate their association with metastasis, Ki-67 index, tumour size, necrosis and survival. Sixty-five carcinomas with solid pattern, basaloid carcinomas, solid papillary carcinomas, malignant adenomyoepitheliomas (MAMEs) or malignant myoepitheliomas (MMEs) were investigated. Luminal A, luminal B HER2 negative and HER2 positive, HER2 overexpressed and triple negative immunophenotypes were immunolabelled as were Ki-67 protein and cyclooxygenase-2 (Cox-2). Histological peritumoural and intratumoural inflammatory infiltrates were graded (distribution × intensity) and the presence of necrosis identified. We found a statistical difference between histological types and immunophenotypes, with MME and MAME having a higher occurrence of luminal A, whereas most neoplasms had the luminal B HER-negative immunophenotype. There was no correlation between immunophenotype and degree of peri- and intratumoural inflammation, nodal metastasis, necrosis or tumour size. An increased degree of peri- and intratumoural inflammation was significantly associated with lymph node metastasis, and more severe intratumoural inflammation was associated with the presence of tumour necrosis. Tumour size, Ki-67 index and Cox-2 score were not associated with inflammation in either peri- or intratumoural regions. No difference was observed in survival in relation to immunophenotype or degree of inflammation, but the Cox regression model revealed that nodal metastasis influenced the risk of death.

Oxidative stress-related genes score predicts prognosis and immune cell infiltration landscape characterization in breast cancer

Background

The tumor microenvironment (TME) typically experiences oxidative stress (OS), marked by a high level of reactive oxygen species (ROS) that can impact tumor advancement and prognosis by modulating the behavior of tumor cells and various immune cells. Oxidative stress-related genes (OSRG) encompass a range of genes involved in ROS pathways, and their specific roles in breast cancer (BC) necessitate further investigation.

Methods

Univariate Cox analysis was performed on genes linked to the OS pathway in the Gene Set Enrichment Analysis (GSEA) database, leading to the identification of 29 significant OSRG in BC. OSRG was divided into three distinct clusters according to the expression and the OSRG score based on the differentially expressed genes (DEGs) was further calculated by principal component analysis (PCA). The correlation between OSRG score and BC clinical features, mutation characteristics, immune checkpoints and immune cell infiltration was analyzed. Establish a multiariable Cox regression model to predict OSRG score effects on clinical characteristics.

Results

Significant differences were observed in survival analysis, enriched pathways, and immune infiltration among the three OSRG clusters based on 29 genes. Gene clusters were identified through the final selected 395 DEGs, revealing three distinct OSRG expression patterns. An OSRG score model was constructed using DEGs, demonstrating a significant association between high OSRG score and poor prognosis. Significantly, immune checkpoint-related genes exhibited a notable upregulation in the high OSRG score cohort. Additionally, a positive correlation was observed between the OSRG score and tumor mutation burden (TMB) in BC. The OSRG score holds potential implications for clinical immunotherapy in BC patients, and a nomogram was constructed with robust predictive capability for evaluating patient prognosis.

Conclusions

This study elucidated the features of OSRG within BC TME and their possible prognostic significance, offering valuable insights for the development of more targeted immunotherapy approaches for individuals with BC.

Breast Cancer Immune Landscape: Interplay Between Systemic and Local Immunity

Breast cancer (BC) is one of the most common malignancies in women worldwide. Numerous studies in immuno-oncology and successful trials of immunotherapy have demonstrated the causal role of the immune system in cancer pathogenesis. The interaction between the tumor and the immune system is known to have a dual nature. Despite cytotoxic lymphocyte activity against transformed cells, a tumor can escape immune surveillance and leverage chronic inflammation to maintain its own development. Research on antitumor immunity primarily focuses on the role of the tumor microenvironment, whereas the systemic immune response beyond the tumor site is described less thoroughly. Here, a comprehensive review of the formation of the immune profile in breast cancer patients is offered. The interplay between systemic and local immune reactions as self-sustaining mechanism of tumor progression is described and the functional activity of the main cell populations related to innate and adaptive immunity is discussed. Additionally, the interaction between different functional levels of the immune system and their contribution to the development of the pro- or anti-tumor immune response in BC is highlighted. The presented data can potentially inform the development of new immunotherapy strategies in the treatment of patients with BC.

A novel preclinical model of the normal human breast

Improved screening and treatment have decreased breast cancer mortality, although incidence continues to rise. Women at increased risk of breast cancer can be offered risk reducing treatments, such as tamoxifen, but this has not been shown to reduce breast cancer mortality. New, more efficacious, risk-reducing agents are needed. The identification of novel candidates for prevention is hampered by a lack of good preclinical models. Current patient derived in vitro and in vivo models cannot fully recapitulate the complexities of the human tissue, lacking human extracellular matrix, stroma, and immune cells, all of which are known to influence therapy response. Here we describe a normal breast explant model utilising a tuneable hydrogel which maintains epithelial proliferation, hormone receptor expression, and residency of T cells and macrophages over 7 days. Unlike other organotypic tissue cultures which are often limited by hyper-proliferation, loss of hormone signalling, and short treatment windows (< 48h), our model shows that tissue remains viable over 7 days with none of these early changes. This offers a powerful and unique opportunity to model the normal breast and study changes in response to various risk factors, such as breast density and hormone exposure. Further validation of the model, using samples from patients undergoing preventive therapies, will hopefully confirm this to be a valuable tool, allowing us to test novel agents for breast cancer risk reduction preclinically.

Exploring the Immunological Profile in Breast Cancer: Recent Advances in Diagnosis and Prognosis through Circulating Tumor Cells

This review offers a comprehensive exploration of the intricate immunological landscape of breast cancer (BC), focusing on recent advances in diagnosis and prognosis through the analysis of circulating tumor cells (CTCs). Positioned within the broader context of BC research, it underscores the pivotal role of the immune system in shaping the disease's progression. The primary objective of this investigation is to synthesize current knowledge on the immunological aspects of BC, with a particular emphasis on the diagnostic and prognostic potential offered by CTCs. This review adopts a thorough examination of the relevant literature, incorporating recent breakthroughs in the field. The methodology section succinctly outlines the approach, with a specific focus on CTC analysis and its implications for BC diagnosis and prognosis. Through this review, insights into the dynamic interplay between the immune system and BC are highlighted, with a specific emphasis on the role of CTCs in advancing diagnostic methodologies and refining prognostic assessments. Furthermore, this review presents objective and substantiated results, contributing to a deeper understanding of the immunological complexity in BC. In conclusion, this investigation underscores the significance of exploring the immunological profile of BC patients, providing valuable insights into novel advances in diagnosis and prognosis through the utilization of CTCs. The objective presentation of findings emphasizes the crucial role of the immune system in BC dynamics, thereby opening avenues for enhanced clinical management strategies.

Mapping the function of MicroRNAs as a critical regulator of tumor-immune cell communication in breast cancer and potential treatment strategies

Among women, breast cancer ranks as the most prevalent form of cancer, and the presence of metastases significantly reduces prognosis and diminishes overall survival rates. Gaining insights into the biological mechanisms governing the conversion of cancer cells, their subsequent spread to other areas of the body, and the immune system's monitoring of tumor growth will contribute to the advancement of more efficient and targeted therapies. MicroRNAs (miRNAs) play a critical role in the interaction between tumor cells and immune cells, facilitating tumor cells' evasion of the immune system and promoting cancer progression. Additionally, miRNAs also influence metastasis formation, including the establishment of metastatic sites and the transformation of tumor cells into migratory phenotypes. Specifically, dysregulated expression of these genes has been associated with abnormal expression of oncogenes and tumor suppressor genes, thereby facilitating tumor development. This study aims to provide a concise overview of the significance and function of miRNAs in breast cancer, focusing on their involvement as tumor suppressors in the antitumor immune response and as oncogenes in metastasis formation. Furthermore, miRNAs hold tremendous potential as targets for gene therapy due to their ability to modulate specific pathways that can either promote or suppress carcinogenesis. This perspective highlights the latest strategies developed for miRNA-based therapies.

Splenic Elemental Composition of Breast Cancer-Suffering Rats Supplemented with Pomegranate Seed Oil and Bitter Melon Extract

The aim of this study was to investigate how dietary modifications with pomegranate seed oil (PSO) and bitter melon aqueous extract (BME) affect mineral content in the spleen of rats both under normal physiological conditions and with coexisting mammary tumorigenesis. The diet of Sprague-Dawley female rats was supplemented either with PSO or with BME, or with a combination for 21 weeks. A chemical carcinogen (7,12-dimethylbenz[a]anthracene) was applied intragastrically to induce mammary tumors. In the spleen of rats, the selected elements were determined with a quadrupole mass spectrometer with inductively coupled plasma ionization (ICP-MS). ANOVA was used to evaluate differences in elemental composition among experimental groups. Multivariate statistical methods were used to discover whether some subtle dependencies exist between experimental factors and thus influence the element content. Experimental factors affected the splenic levels of macroelements, except for potassium. Both diet modification and the cancerogenic process resulted in significant changes in the content of Fe, Se, Co, Cr, Ni, Al, Sr, Pb, Cd, B, and Tl in rat spleen. Chemometric analysis revealed the greatest impact of the ongoing carcinogenic process on the mineral composition of the spleen. The obtained results may contribute to a better understanding of peripheral immune organ functioning, especially during the neoplastic process, and thus may help develop anticancer prevention and treatment strategies.

Exploring the dynamic interplay between exosomes and the immune tumor microenvironment: implications for breast cancer progression and therapeutic strategies

Breast cancer continues to pose a substantial worldwide health concern, demanding a thorough comprehension of the complex interaction between cancerous cells and the immune system. Recent studies have shown the significant function of exosomes in facilitating intercellular communication and their participation in the advancement of cancer. Tumor-derived exosomes have been identified as significant regulators in the context of breast cancer, playing a crucial role in modulating immune cell activity and contributing to the advancement of the illness. This study aims to investigate the many effects of tumor-derived exosomes on immune cells in the setting of breast cancer. Specifically, we will examine their role in influencing immune cell polarization, facilitating immunological evasion, and modifying the tumor microenvironment. Furthermore, we explore the nascent domain of exosomes produced from immune cells and their prospective involvement in the prevention of breast cancer. This paper focuses on new research that emphasizes the immunomodulatory characteristics of exosomes produced from immune cells. It also explores the possibility of these exosomes as therapeutic agents or biomarkers for the early identification and prevention of breast cancer. The exploration of the reciprocal connections between exosomes formed from tumors and immune cells, together with the rising significance of exosomes derived from immune cells, presents a potential avenue for the advancement of novel approaches in the field of breast cancer therapy and prevention.

Potential of the postoperative lymphocyte-to-monocyte and monocyte-to-red blood cell ratio in predicting locoregional and distant metastases after breast cancer resection - Retrospective study

PURPOSE

Breast cancer is the most common malignancy with high recurrence and mortality rates in women. There are still insufficient biomarkers to predict disease prognosis. Therefore, the present study aimed to investigate the clinical significance of postoperative hematologic parameters and their derivatives in patients with breast cancer who underwent tumor resection.

PATIENTS AND METHODS

The clinicopathological and laboratory data of 90 female breast cancer patients who underwent surgical treatment in the Greater Poland Cancer Center in Poznan from December 2015 to November 2017 were retrospectively analyzed. Postoperative hematologic parameters, including neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte ratio (PLR), monocyte-to-red blood cell ratio (MRR), lymphocyte-to-red blood cell ratio (LRR), platelet-to-red blood cell ratio (PRR) were evaluated in recurrence and non-recurrence group. Receiver-operating characteristic (ROC) curve analysis was used to assess the optimal cutoff value of postoperative hematologic parameters for tumor recurrence. The association of postoperative hematologic parameters with disease-free survival (DFS) was investigated by the Kaplan-Meier method and Cox regression analysis.

RESULTS

Patients with local, regional, or distant metastases accounted for 14% of the total. The postoperative monocyte count and MRR were significantly elevated, whereas postoperative LMR was statistically decreased in the recurrence group. Univariate and multivariate Cox analysis revealed that postoperative LMR ≤3.044 and postoperative MRR >0.1398 were associated with significantly shorter DFS.

CONCLUSION

Our results revealed that both postoperative LMR and MRR are independent predictors of DFS in breast cancer patients. Large-scale prospective investigations are needed to validate our findings.

Engineered 3D ex vivo models to recapitulate the complex stromal and immune interactions within the tumor microenvironment

Cancer thrives in a complex environment where interactions between cellular and acellular components, surrounding the tumor, play a crucial role in disease development and progression. Despite significant progress in cancer research, the mechanism driving tumor growth and therapeutic outcomes remains elusive. Two-dimensional (2D) cell culture assays and in vivo animal models are commonly used in cancer research and therapeutic testing. However, these models suffer from numerous shortcomings including lack of key features of the tumor microenvironment (TME) & cellular composition, cost, and ethical clearance. To that end, there is an increased interest in incorporating and elucidating the influence of TME on cancer progression. Advancements in 3D-engineered ex vivo models, leveraging biomaterials and microengineering technologies, have provided an unprecedented ability to reconstruct native-like bioengineered cancer models to study the heterotypic interactions of TME with a spatiotemporal organization. These bioengineered cancer models have shown excellent capabilities to bridge the gap between oversimplified 2D systems and animal models. In this review article, we primarily provide an overview of the immune and stromal cellular components of the TME and then discuss the latest state-of-the-art 3D-engineered ex vivo platforms aiming to recapitulate the complex TME features. The engineered TME model, discussed herein, are categorized into three main sections according to the cellular interactions within TME: (i) Tumor-Stromal interactions, (ii) Tumor-Immune interactions, and (iii) Complex TME interactions. Finally, we will conclude the article with a perspective on how these models can be instrumental for cancer translational studies and therapeutic testing.

Unveiling the Immune Microenvironment's Role in Breast Cancer: A Glimpse into Promising Frontiers

Breast cancer (BC), one of the most widespread and devastating diseases affecting women worldwide, presents a significant public health challenge. This review explores the emerging frontiers of research focused on deciphering the intricate interplay between BC cells and the immune microenvironment. Understanding the role of the immune system in BC is critical as it holds promise for novel therapeutic approaches and precision medicine strategies. This review delves into the current literature regarding the immune microenvironment's contribution to BC initiation, progression, and metastasis. It examines the complex mechanisms by which BC cells interact with various immune cell populations, including tumor-infiltrating lymphocytes (TILs) and tumor-associated macrophages (TAMs). Furthermore, this review highlights the impact of immune-related factors, such as cytokines and immune checkpoint molecules. Additionally, this comprehensive analysis sheds light on the potential biomarkers associated with the immune response in BC, enabling early diagnosis and prognostic assessment. The therapeutic implications of targeting the immune microenvironment are also explored, encompassing immunotherapeutic strategies and combination therapies to enhance treatment efficacy. The significance of this review lies in its potential to pave the way for novel therapeutic interventions, providing clinicians and researchers with essential knowledge to design targeted and personalized treatment regimens for BC patients.

Maternal obesity driven changes in collagen linearity of breast extracellular matrix induces invasive mammary epithelial cell phenotype

Obesity has been linked with numerous health issues as well as an increased risk of breast cancer. Although effects of direct obesity in patient outcomes is widely studied, effects of exposure to obesity-related systemic influences in utero have been overlooked. In this study, we investigated the effect of multigenerational obesity on epithelial cell migration and invasion using decellularized breast tissues explanted from normal female mouse pups from a diet induced multigenerational obesity mouse model. We first studied the effect of multigenerational diet on the mechanical properties, adipocyte size, and collagen structure of these mouse breast tissues, and then, examined the migration and invasion behavior of normal (KTB-21) and cancerous (MDA-MB-231) human mammary epithelial cells on the decellularized matrices from each diet group. Breast tissues of mice whose dams had been fed with high-fat diet exhibited larger adipocytes and thicker and curvier collagen fibers, but only slightly elevated elastic modulus and inflammatory cytokine levels. MDA-MB-231 cancer cell motility and invasion were significantly greater on the decellularized matrices from mice whose dams were fed with high-fat diet. A similar trend was observed with normal KTB-21 cells. Our results showed that the collagen curvature was the dominating factor on this enhanced motility and stretching the matrices to equalize the collagen fiber linearity of the matrices ameliorated the observed increase in cell migration and invasion in the mice that were exposed to a high-fat diet in utero. Previous studies indicated an increase in serum leptin concentration for those children born to an obese mother. We generated extracellular matrices using primary fibroblasts exposed to various concentrations of leptin. This produced curvier ECM and increased breast cancer cell motility for cells seeded on the decellularized ECM generated with increasing leptin concentration. Our study shows that exposure to obesity in utero is influential in determining the extracellular matrix structure, and that the resultant change in collagen curvature is a critical factor in regulating the migration and invasion of breast cancer cells.

Characteristics and postoperative dynamic changes in circulating CD4+ helper T lymphocytes in patients with breast cancer

Introduction

Circulating CD4⁺ helper T cell (Th) subsets provide potentially important information on disease progression in several cancers. In this study, we explored the characteristics and postoperative dynamic changes in circulating CD4⁺Th subsets in patients with breast cancer.

Methods

Circulating CD4⁺Th subsets, including CD4⁺ naive T cells (Tn), CD4⁺ central memory T cells (Tcm), CD4⁺ effector memory T cells (Tem), CD4⁺CD57⁺T, and CD4⁺PD-1⁺T, were detected with multiparameter flow cytometry. T-test and Wilcoxon rank-sum test were used to compare differences between groups for normally and non-normally distributed continuous variables, respectively. Postoperative dynamic changes in CD4⁺Th subsets were assessed using the paired-sample rank-sum test.

Results

Seventy-five patients with invasive breast cancer and fifty-three patients with benign breast tumors were enrolled. Compared with that in patients with benign tumors, the proportion of CD4⁺Tn in patients with breast cancer patients decreased, whereas the proportion and absolute number of CD4⁺CD57⁺T and CD4⁺PD-1⁺T increased. Moreover, the proportion of CD4⁺PD-1⁺T was correlated with the clinicopathology of breast cancer. After tumor resection, the proportion and absolute number of CD4⁺Tcm significantly decreased, while those of CD4⁺Tem significantly increased, compared with preoperative values. Tumor resection caused significant changes in the proportion and absolute number of CD4⁺CD57⁺T and CD4⁺PD-1⁺ T, both of which showed significant decreases.

Discussion

We found significant changes in circulating CD4⁺Th subsets in patients with breast cancer. Additionally, complete tumor resection can benefit the patient as it balances the patient's immunosuppression and immune stress and improves the immune exhaustion and immunosenescence states.

Updates in combined approaches of radiotherapy and immune checkpoint inhibitors for the treatment of breast cancer

Breast cancer is the most prevalent non-skin cancer diagnosed in females and developing novel therapeutic strategies to improve patient outcomes is crucial. The immune system plays an integral role in the body’s response to breast cancer and modulating this immune response through immunotherapy is a promising therapeutic option. Although immune checkpoint inhibitors were recently approved for the treatment of breast cancer patients, not all patients respond to immune checkpoint inhibitors as a monotherapy, highlighting the need to better understand the biology underlying patient response. Additionally, as radiotherapy is a critical component of breast cancer treatment, understanding the interplay of radiation and immune checkpoint inhibitors will be vital as recent studies suggest that combined therapies may induce synergistic effects in preclinical models of breast cancer. This review will discuss the mechanisms supporting combined approaches with radiotherapy and immune checkpoint inhibitors for the treatment of breast cancer. Moreover, this review will analyze the current clinical trials examining combined approaches of radiotherapy, immunotherapy, chemotherapy, and targeted therapy. Finally, this review will evaluate data regarding treatment tolerance and potential biomarkers for these emerging therapies aimed at improving breast cancer outcomes.

Luminal androgen receptor breast cancer subtype and investigation of the microenvironment and neoadjuvant chemotherapy response

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype with low overall survival rates and high molecular heterogeneity; therefore, few targeted therapies are available. The luminal androgen receptor (LAR) is the most consistently identified TNBC subtype, but the clinical utility has yet to be established. Here, we constructed a novel genomic classifier, LAR-Sig, that distinguishes the LAR subtype from other TNBC subtypes and provide evidence that it is a clinically distinct disease. A meta-analysis of seven TNBC datasets (n = 1086 samples) from neoadjuvant clinical trials demonstrated that LAR patients have significantly reduced response (pCR) rates than non-LAR TNBC patients (odds ratio = 2.11, 95% CI: 1.33, 2.89). Moreover, deconvolution of the tumor microenvironment confirmed an enrichment of luminal epithelium corresponding with a decrease in basal and myoepithelium in LAR TNBC tumors. Increased immunosuppression in LAR patients may lead to a decreased presence of cycling T-cells and plasma cells. While, an increased presence of myofibroblast-like cancer-associated cells may impede drug delivery and treatment. In summary, the lower levels of tumor infiltrating lymphocytes (TILs), reduced immune activity in the micro-environment, and lower pCR rates after NAC, suggest that new therapeutic strategies for the LAR TNBC subtype need to be developed.

Plg-RKT Expression in Human Breast Cancer Tissues

The plasminogen activation system regulates the activity of the serine protease, plasmin. The role of plasminogen receptors in cancer progression is being increasingly appreciated as key players in modulation of the tumor microenvironment. The interaction of plasminogen with cells to promote plasminogen activation requires the presence of proteins exposing C-terminal lysines on the cell surface. Plg-R_KT is a structurally unique plasminogen receptor because it is an integral membrane protein that is synthesized with and binds plasminogen via a C-terminal lysine exposed on the cell surface. Here, we have investigated the expression of Plg-R_KT in human breast tumors and human breast cancer cell lines. Breast cancer progression tissue microarrays were probed with anti-Plg-R_KT mAB and we found that Plg-R_KT is widely expressed in human breast tumors, that its expression is increased in tumors that have spread to draining lymph nodes and distant organs, and that Plg-R_KT expression is most pronounced in hormone receptor (HR)-positive tumors. Plg-R_KT was detected by Western blotting in human breast cancer cell lines. By flow cytometry, Plg-R_KT cell surface expression was highest on the most aggressive tumor cell line. Future studies are warranted to address the functions of Plg-R_KT in breast cancer.