Immunotherapy In Triple-negative Breast Cancer Research Articles

Regression of Triple-Negative Breast Cancer in a Patient-Derived Xenograft Mouse Model by Monoclonal Antibodies against IL-12 p40 Monomer.

Although some therapies are available for regular breast cancers, there are very few options for triple-negative breast cancer (TNBC). Here, we demonstrated that serum level of IL-12p40 monomer (p40) was much higher in breast cancer patients than healthy controls. On the other hand, levels of IL-12, IL-23 and p40 homodimer (p402) were lower in serum of breast cancer patients as compared to healthy controls. Similarly, human TNBC cells produced greater level of p40 than p402. The level of p40 was also larger than p402 in serum of a patient-derived xenograft (PDX) mouse model. Accordingly, neutralization of p40 by p40 mAb induced death of human TNBC cells and tumor shrinkage in PDX mice. While investigating the mechanism, we found that neutralization of p40 led to upregulation of human CD4+IFNγ+ and CD8+IFNγ+ T cell populations, thereby increasing the level of human IFNγ and decreasing the level of human IL-10 in PDX mice. Finally, we demonstrated the infiltration of human cytotoxic T cells, switching of tumor-associated macrophage M2 (TAM2) to TAM1 and suppression of transforming growth factor β (TGFβ) in tumor tissues of p40 mAb-treated PDX mice. Our studies identify a possible new immunotherapy for TNBC in which p40 mAb inhibits tumor growth in PDX mice.

Clinical Progress of PD-1/L1 Inhibitors in Breast Cancer Immunotherapy.

Breast cancer is a major killer of women’s health worldwide. While breast cancer is thought to have lower immunogenicity compared with other solid tumors, combination therapy is able to improve the immunogenicity of the tumor and sensitize breast cancer cells to immunotherapy. Immunotherapy represented by immune checkpoint inhibitors (ICIs) has been largely explored in the field of breast cancer, including both early and advanced disease. Immunotherapy for triple-negative breast cancer (TNBC) has been the most studied, and the PD-L1 inhibitor atezolizumab combined with nab-paclitaxel has been used in the first-line treatment of TNBC. Immunotherapeutic data for human epidermal growth factor receptor-positive and hormone receptor-positive breast cancer are also accumulating. This review summarizes the clinical trial data of ICIs or ICI-containing therapies in different types and stages of breast cancer.

Immune Checkpoint Inhibitors in Triple Negative Breast Cancer: The Search for the Optimal Biomarker.

Triple negative breast cancer (TNBC) is a high-risk and aggressive malignancy characterized by the absence of estrogen receptors (ER) and progesterone receptors (PR) on the surface of malignant cells, and by the lack of overexpression of human epidermal growth factor 2 (HER2). It has limited therapeutic options compared to other subtypes of breast cancer. There is now a growing body of evidence on the role of immunotherapy in TNBC, however much of the data from clinical trials is conflicting and thus, challenging for clinicians to integrate the data into clinical practice. Landmark phase III trials using immunotherapy in the early-stage neoadjuvant setting concluded that the addition of immunotherapy to chemotherapy improved the pathologic complete response (pCR) rate compared to chemotherapy with placebo while others found no significant improvement in pCR. Phase III trials have investigated the utility of immunotherapy in previously untreated metastatic TNBC, and these studies have similarly arrived at inconsistent conclusions. Some studies showed no benefit while others demonstrated a clinically significant improvement in overall survival in the PD-L1 positive population. It is not yet clear which biomarkers are most useful, and assays for these biomarkers have not been standardized. Given the often serious and severe side effects of immunotherapy, it is important and necessary to identify predictive biomarkers of response and resistance in order to enhance patient selection. In this review, we will discuss both the challenges of traditional biomarkers and the opportunities of emerging biomarkers for patient selection.

Abstract P059: An increase in eosinophils is associate with response to chemo-immunotherapy in metastatic triple negative breast cancer

Abstract Background: Several trials have reported on eosinophilia in cancer patients receiving immunotherapy therapy of cancer especially checkpoint inhibitors. There is limited reports on eosinophilia and immunotherapy in triple-negative breast cancer (TNBC). Patients: We are reporting on eosinophilia and the increase in eosinophil count in a trial testing the combination of Durvalumab band paclitaxel in metastatic TNBC NCT02628132. In this trial 19 patients were recruited, however, only 14 received the combination therapy while the 5 drop out due to progression on paclitaxel alone priming cycle. Results: One of the patients developed eosinophilia after having a complete response status. The developed eosinophilia lasted for a year and subsided with temporary holding treatment. Among all patients enrolled who received the combination therapy, there was a statistically significant correlation between an increase in eosinophil count (>300/mm3) during treatment and a having partial or complete response to the combination therapy (p 0.028). In agreement, survival analysis showed a significant association between disease-free survival (DFS) and higher PCE count (p 0.005). A similar trend existed with overall survival (OS), although it did not reach significance (p 0.167). The increase in eosinophil count correlated significantly with skin rash/pruritus (p 0.028). On the other hand, the association between baseline PEC before treatment and response to treatment was not statistically significant despite the positive trend. Conclusions: An increase in circulating eosinophil count correlates with response to therapy with chemo-immunotherapy combination in metastatic TNBC. This study supports the role eosinophils are playing in the treatment of cancer. Citation Format: Hazem Ghebeh, Mahmoud A. Elshenawy, Adher Al-Sayed, Taher Al-Tweigeri. An increase in eosinophils is associate with response to chemo-immunotherapy in metastatic triple negative breast cancer [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr P059.

Immunotherapy for triple-negative breast cancer: Time to pause?

Immunotherapy for triple-negative breast cancer: Time to pause?

The relationship between the efficacy of talazoparib and the functional toll-like receptors 3 and 9 in triple negative breast cancer

Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) induce cell death by inhibiting the repair of DNA strand breaks binding to PARP and regulate immune cells functions. Toll-like receptors (TLRs) mediate the tumor microenvironment through the modulation of proinflammatory cytokines and chemokines. In this context, this study addressed the relationship between the efficacy of talazoparib (TAL) as a PARPi and the activation of TLR3 or TLR9 by Polyinosinic:polycytidylic acid (Poly I:C) or CpG oligodeoxynucleotides (CpG-ODN) stimulation, respectively in triple negative breast cancer (TNBC). TAL alone and the combination of TAL with Poly I:C or CpG-ODN induced cell death were analyzed by water-soluble tetrazolium salt 1 (WST-1), Annexin V analysis, acridine orange staining and mRNA levels of caspase-3 and caspase-8 in HCC1937 and HCC1937-R (TAL resistant) TNBC cells. Additionally, the expression of TLR3, TLR9 and interferon regulatory factor 7 (IRF7) was observed with immunofluorescence staining and western blot analysis. Our findings showed that TAL induced TLR3 and TLR9 activation and acted in synergy with TLR3 and TLR9 agonists in TNBC cells. The stimulation of TLR3 or TLR9 and TAL treatment caused significantly more apoptosis in TNBC cells through the over-expression of caspase-3 and caspase-8. Additionally, TAL combined with Poly I:C or CpG-ODN more increased TLR3, TLR9 and IRF7 protein levels in HCC1937 cells and treatment with TAL and Poly I:C had greater potential for overcoming TAL resistance. In conclusion, the combination of PARPi with TLR agonists may be a new therapeutic combined strategy for the effective immunotherapy of TNBC.

Immunotherapy for Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is characterized by extensive tumor heterogeneity at both the pathologic and molecular levels, particularly accelerated aggressiveness, and terrible metastasis. It is responsible for the increased mortality of breast cancer patients. Due to the negative expression of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2, the progress of targeted therapy has been hindered. Higher immune response in TNBCs than for other breast cancer types makes immunotherapy suitable for TNBC therapy. At present, promising treatments in immunotherapy of TNBC include immune checkpoints (ICs) blockade therapy, adoptive T-cell immunotherapy, and tumor vaccine immunotherapy. In addition, nanomedicines exhibit great potential in cancer therapy through the enhanced permeability and retention (EPR) effect. Immunotherapy-involved combination therapy may exert synergistic effects by combining with other treatments, such as traditional chemotherapy and new treatments, including photodynamic therapy (PTT), photodynamic therapy (PDT), and sonodynamic therapy (SDT). This review focuses on introducing the principles and latest development as well as progress in using nanocarriers as drug-delivery systems for the immunotherapy of TNBC.

Targeted immunotherapy of triple-negative breast cancer by aptamer-engineered NK cells

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer comprised of cells that lack expression of targetable biomarkers. Nucleic acid aptamers are a group of molecular ligands that can specifically bind to their targets with high affinity. The ssDNA aptamer PDGC21-T recognizes poorly differentiated cancer cells and tumor tissues through an unidentified cell surface target(s). Because TNBC tumor cells are poorly differentiated, the aptamer PDGC21-T is a promising therapeutic candidate to target TNBC tumor cells. In vitro study revealed that synthetic aptamer probes selectively targeted TNBC cell lines. To assess aptamer immunotherapeutic targeting capability, we generated aptamer-engineered NK cells (ApEn-NK) using aptamer probes as a targeting ligand and NK cells as a therapeutic agent. Cell clustering formation assays revealed that ApEn-NK bound both suspended and adherent TNBC cells with high affinity. In a functional study, ApEn-NK treatment triggered apoptosis and death of cultured TNBC cells. Finally, systemic administration of ApEn-NK in mice harboring TNBC xenografts resulted in significant inhibition of lung metastasis relative to parental NK cell treatments. Unlike chemotherapy, ApEn-NK treatment did not affect body weight in treated mice. We demonstrate a novel approach for targeted TNBC immunotherapy.

Immune Classification and Immune Landscape Analysis of Triple-Negative Breast Cancer.

Background: To classify triple-negative breast cancer (TNBC) immunotyping using the public database, analyze the differences between subtypes in terms of clinical characteristics and explore the role and clinical significance of immune subtypes in TNBC immunotherapy. Methods: We downloaded TNBC data from the cBioPortal and GEO databases. The immune genes were grouped to obtain immune gene modules and annotate their biological functions. Log-rank tests and Cox regression were used to evaluate the prognosis of immune subtypes (IS). Drug sensitivity analysis was also performed for the differences among immune subtypes in immunotherapy and chemotherapy. In addition, dimension reduction analysis based on graph learning was utilized to reveal the internal structure of the immune system and visualize the distribution of patients. Results: Significant differences in prognosis were observed between subtypes (IS1, IS2, and IS3), with the best in IS3 and the worst in IS1. The sensitivity of IS3 to immunotherapy and chemotherapy was better than the other two subtypes. In addition, Immune landscape analysis found the intra-class heterogeneity of immune subtypes and further classified IS3 subtypes (IS3A and IS3B). Immune-related genes were divided into seven functional modules (The turquoise module has the worst prognosis). Five hub genes (RASSF5, CD8A, ICOS, IRF8, and CD247) were screened out as the final characteristic genes related to poor prognosis by low expression. Conclusions: The immune subtypes of TNBC were significantly different in prognosis, gene mutation, immune infiltration, drug sensitivity, and heterogeneity. We validated the independent role of immune subtypes in tumor progression and immunotherapy for TNBC. This study provides a new perspective for personalized immunotherapy and the prognosis evaluation of TNBC patients in the future.

Characterization of Exosome-Related Gene Risk Model to Evaluate the Tumor Immune Microenvironment and Predict Prognosis in Triple-Negative Breast Cancer.

BackgroundAs a kind of small membrane vesicles, exosomes are secreted by most cell types from multivesicular endosomes, including tumor cells. The relationship between exosomes and immune response plays a vital role in the occurrence and development of tumors. Nevertheless, the interaction between exosomes and the microenvironment of tumors remains unclear. Therefore, we set out to study the influence of exosomes on the triple-negative breast cancer (TNBC) microenvironment.MethodOne hundred twenty-one exosome-related genes were downloaded from ExoBCD database, and IVL, CXCL13, and AP2S1 were final selected because of the association with TNBC prognosis. Based on the sum of the expression levels of these three genes, provided by The Cancer Genome Atlas (TCGA), and the regression coefficients, an exosome risk score model was established. With the median risk score value, the patients in the two databases were divided into high- and low-risk groups. R clusterProfiler package was employed to compare the different enrichment ways between the two groups. The ESTIMATE and CIBERSORT methods were employed to analyze ESTIMATE Score and immune cell infiltration. Finally, the correlation between the immune checkpoint-related gene expression levels and exosome-related risk was analyzed. The relationship between selected gene expression and drug sensitivity was also detected.ResultsDifferent risk groups exhibited distinct result of TNBC prognosis, with a higher survival rate in the low-risk group than in the high-risk group. The two groups were enriched by immune response and biological process pathways. A better overall survival (OS) was demonstrated in patients with high scores of immune and ESTIMATE rather than ones with low scores. Subsequently, we found that CD4+-activated memory T cells and M1 macrophages were both upregulated in the low-risk group, whereas M2 macrophages and activated mast cell were downregulated in the low-risk group in patients from the TCGA and GEO databases, respectively. Eventually, four genes previously proposed to be targets of immune checkpoint inhibitors were evaluated, resulting in the expression levels of CD274, CTLA4, LAG3, and TIM3 being higher in the low-risk group than high-risk group.ConclusionThe results of our study suggest that exosome-related risk model was related to the prognosis and ratio of immune cell infiltration in patients with TNBC. This discovery may make contributions to improve immunotherapy for TNBC.

KAT6A Acetylation of SMAD3 Regulates Myeloid-Derived Suppressor Cell Recruitment, Metastasis, and Immunotherapy in Triple-Negative Breast Cancer.

Aberrant SMAD3 activation has been implicated as a driving event in cancer metastasis, yet the underlying mechanisms are still elusive. Here, SMAD3 is identified as a nonhistone substrate of lysine acetyltransferase 6A (KAT6A). The acetylation of SMAD3 at K20 and K117 by KAT6A promotes SMAD3 association with oncogenic chromatin modifier tripartite motif‐containing 24 (TRIM24) and disrupts SMAD3 interaction with tumor suppressor TRIM33. This event in turn promotes KAT6A‐acetylated H3K23‐mediated recruitment of TRIM24–SMAD3 complex to chromatin and thereby increases SMAD3 activation and immune response‐related cytokine expression, leading to enhanced breast cancer stem‐like cell stemness, myeloid‐derived suppressor cell (MDSC) recruitment, and triple‐negative breast cancer (TNBC) metastasis. Inhibiting KAT6A in combination with anti‐PD‐L1 therapy in treating TNBC xenograft‐bearing animals markedly attenuates metastasis and provides a significant survival benefit. Thus, the work presents a KAT6A acetylation‐dependent regulatory mechanism governing SMAD3 oncogenic function and provides insight into how targeting an epigenetic factor with immunotherapies enhances the antimetastasis efficacy.

TNBC: Potential Targeting of Multiple Receptors for a Therapeutic Breakthrough, Nanomedicine, and Immunotherapy.

Triple-negative breast cancer (TNBC) is a heterogeneous, recurring cancer associated with a high rate of metastasis, poor prognosis, and lack of therapeutic targets. Although target-based therapeutic options are approved for other cancers, only limited therapeutic options are available for TNBC. Cell signaling and receptor-specific targets are reportedly effective in patients with TNBC under specific clinical conditions. However, most of these cancers are unresponsive, and there is a requirement for more effective treatment modalities. Further, there is a lack of effective biomarkers that can distinguish TNBC from other BC subtypes. ER, PR, and HER2 help identify TNBC and are widely used to identify patients who are most likely to respond to diverse therapeutic strategies. In this review, we discuss the possible treatment options for TNBC based on its inherent subtype receptors and pathways, such as p53 signaling, AKT signaling, cell cycle regulation, DNA damage, and programmed cell death, which play essential roles at multiple stages of TNBC development. We focus on poly-ADP ribose polymerase 1, androgen receptor, vascular endothelial growth factor receptor, and epidermal growth factor receptor as well as the application of nanomedicine and immunotherapy in TNBC and discuss their potential applications in drug development for TNBC.

A new immunochemical strategy for triple-negative breast cancer therapy

Triple-negative breast cancer (TNBC) is a highly diverse group of malignant neoplasms which tend to have poor outcomes, and the development of new targets and strategies to treat these cancers is sorely needed. Antibody–drug conjugate (ADC) therapy has been shown to be a promising targeted therapy for treating many cancers, but has only rarely been tried in patients with TNBC. A major reason the efficacy of ADC therapy in the setting of TNBC has not been more fully investigated is the lack of appropriate target molecules. In this work we were able to identify an effective TNBC target for use in immunotherapy. We were guided by our previous observation that in some breast cancer patients the protein tropomyosin receptor kinase B cell surface protein (TrkB) had become immunogenic, suggesting that it was somehow sufficiently chemically different enough (presumably by mutation) to escaped immune tolerance. We postulated that this difference might well offer a means for selective targeting by antibodies. We engineered site-specific ADCs using a dual variable domain (DVD) format which combines anti-TrkB antibody with the h38C2 catalytic antibody. This format enables rapid, one-step, and homogeneous conjugation of β-lactam-derivatized drugs. Following conjugation to β-lactam-derivatized monomethyl auristatin F, the TrkB-targeting DVD-ADCs showed potency against multiple breast cancer cell lines, including TNBC cell lines. In addition, our isolation of antibody that specifically recognized the breast cancer-associated mutant form of TrkB, but not the wild type TrkB, indicates the possibility of further refining the selectivity of anti-TrkB DVD-ADCs, which should enhance their therapeutic index. These results confirmed our supposition that TrkB is a potential target for immunotherapy for TNBC, as well as for other cancers with mutated cell surface proteins.

Progress of Tumor Infiltrating Lymphocytes in Immunotherapy of Triple Negative Breast Cancer

Breast cancer has become the most common cancer for women in China.Lack of effective therapeutic targets,triple negative breast cancer(TNBC)has poorer prognosis compared with other subtypes of breast cancer.Tumor infiltrating lymphocytes(TILs)are a group of heterogeneous lymphocytes around the tumor,which are believed as immunoreactive products of host immune response to tumor antigens.At present,there have been reports on the predictive effect of TILs on the prognosis of breast cancer,and the available studies focus mainly on TNBC.This article briefly reviews the recent progress of tumor infiltrating lymphocytes in immunotherapy of TNBC.

Carbon nanotubes (CNT)-loaded ginsenosides Rb3 suppresses the PD-1/PD-L1 pathway in triple-negative breast cancer.

Carbon nanotubes (CNTs), as advanced nanotechnology with specific properties and structures, have presented practical drug delivery properties. Ginsenoside Rg3 is a component of puffed ginseng and demonstrates anti-cancer activities. To explore the effect of CNTs-loaded Rg3 (Rg3-CNT) on the PD-1/PD-L1 signaling and the development of triple-negative breast cancer (TNBC). Our data revealed that Rg3 inhibited the cell viability of TNBC cells, in which Rg3-CNT further enhanced this effect in the system. Similarly, the colony formation of TNBC cells was decreased by Rg3, while Rg3-CNT could reinforce its effect in the cells. Besides, the treatment of Rg3 induced apoptosis of TNBC cells, in which Rg3-CNT treatment further increased the phenotype in the cells. Remarkably, Rg3-CNT, but not Rg3, attenuated PD-L1 expression in TNBC cells. Rg3-CNT decreased the PD-L1 upregulation induced by interferon-γ (IFN-γ) in breast cancer cells. Importantly, Rg3-CNT was able to reduce PD-1 expression in activated T cells. Specifically, Rg3-CNT reduced the PD-1/PD-L1 axis in a T cell/triple-negative TNBC cell co-culture system. Moreover, the levels of IFN-γ, interleukins-2 (IL-2), interleukins-9 (IL-9), interleukins-10 (IL-10), interleukins-22 (IL-22), and interleukins-23 (IL-23) were significantly stimulated in the activated T cells, while the treatment of Rg3-CNT could reverse these phenotypes in the cells. Rg3-CNT attenuated the TNBC cell growth in vivo. The Rg3-CNT improved the anti-cancer effect of Rg3 toward TNBC by inhibiting the PD-1/PD-L1 axis. Our finding provides new insights into the mechanism by which Rg3-CNT attenuates the development of TNBC. Rg3-CNT may be applied as the potential therapeutic strategy for immunotherapy of TNBC.

Prognostic and Clinicopathologic Associations of LAG-3 Expression in Triple-negative Breast Cancer.

The immune checkpoint molecule lymphocyte activation gene 3 (LAG-3) is currently being investigated as a possible target for immunotherapy in triple-negative breast cancer (TNBC), frequently as an addition to treatment with programmed cell death protein 1/programmed death ligand 1 (PD-L1) inhibition. However, expression of LAG-3, the frequency of coexpression with PD-L1, and the prognostic significance of this marker have not been studied extensively in TNBC. For this study, tissue microarrays (TMAs) were constructed from surgical specimens of 514 patients with TNBC. TMAs were stained immunohistochemically for LAG-3 and PD-L1 expression. Tumor-infiltrating lymphocytes (TILs) were evaluated on full glass slides. LAG-3 expression was significantly associated with improved overall survival and relapse-free survival. When adjusted for clinicopathologic factors, each increment of 10 LAG-3-positive intratumoral lymphocytes per TMA core was associated with improved overall survival (hazard ratio=0.93, 95% confidence interval: 0.89-0.97, P=0.002), and recurrence-free survival (hazard ratio=0.91, 95% confidence interval: 0.85-0.97, P=0.002). PD-L1 expression on immune cells and PD-L1 expression evaluated with the combined positive score and TILs were also associated with improved survival in both univariate and multivariate analyses. PD-L1 expression on tumor cells was only associated with improved survival in univariate analysis. LAG-3 expression was associated with both TILs and PD-L1 expression. Coexpression of LAG-3 and PD-L1 did not confer additional survival benefits. In conclusion, LAG-3 expression is associated with improved survival in TNBC. LAG-3 is often coexpressed with PD-L1, confirming that TNBC is likely a suitable candidate for cotreatment with LAG-3 and programmed cell death protein 1/PD-L1 inhibitors. However, coexpression does not confer additional survival benefits.

Antiangiogenic therapy for breast cancer with triple negative phenotype

Triple-negative breast cancer is 1024% of all cases of breast cancer and is characterized by the absence of estrogen, progesterone, and HER-2 receptors in the tumor. The therapy of this illness is a difficult clinical case. In contrast to hormone-positive and HER-2-positive phenotypes, in which we successfully use targeted drugs (antiestrogens and anti-HER-2 drugs), for triple-negative breast cancer we have not had such targets for a long time. Thus, despite the impressive results of immunotherapy of triple-negative breast cancer, there remains a fairly large group of patients with negative PD-L1 status, for whom it is necessary to develop other treatment strategies. One of the approaches in the treatment of malignant tumors includes not the impact on tumor cells, but the process of angiogenesis. Antiangiogenic drugs have positively proven themselves in the treatment of a large number of malignant tumors but are underestimated for breast cancer (including triple-negative phenotype). The use of bevacizumab in combinations with cytostatic drugs in breast cancer therapy (including triple-negative breast cancer) has been studied in a large number of clinical trials but was undeservedly forgotten in some countries due to the revoked FDA registration. This review presents the role of bevacizumab in the treatment of patients with triple-negative breast cancer and suggests the conditions when the administration of this drug is justified and leads to better results.

The prognostic significance of TILs as a biomarker in triple-negative breast cancer: what is the role of TILs in TME of TNBC?

Triple-negative breast cancer (TNBC) accounts for approximately 15-20% of all breast cancers, and its poor response to treatment has been a major problem in the field of breast cancer. In recent years, the application of immune checkpoint inhibitors has introduced a new era of treatment. The IMpassion 130 trial used PD-L1 as a mature biomarker for immunotherapy in metastatic TNBC, but the population screened, which was only patients with positive PD-L1 expression, was too narrow. Otherwise, it could not be determined whether the PD-L1-positive group benefited from immunotherapy in early TNBC, but this was confirmed in the KEYNOTE-522 and IMpassion 031 studies, in which there was no significant difference in the benefit, whether patients were PD-L1-positive or not. Therefore, how to screen more suitable biomarkers for accurate immunotherapy has become a burning and persistent problem to be solved. In fact, immune infiltration has always been our focus in the process of exploring immunotherapy in TNBC, and tumor infiltrating lymphocytes (TILs) have been well-known for decades as a prognostic factor in early TNBC. Furthermore, TILs are positively correlated with both patient survival and pathological complete response (pCR) after neoadjuvant chemotherapy. Recently, increasingly more foundational experiments and clinical trial verifications suggest that TILs could contain more biomarkers. Thus, in this review, we will assess the composition and heterogeneity of TILs, their evaluation standards, their relationship with TNBC prognosis and the prediction ability of different treatment options in TNBC, and their correlation with other biomarkers in the clinical application. We also summarize new studies that show the future potential of TILs.

Effect of cabazitaxel on macrophages improves CD47-targeted immunotherapy for triple-negative breast cancer

BackgroundLimited therapeutic options are available for triple-negative breast cancer (TNBC), emphasizing an urgent need for more effective treatment approaches. The development of strategies by targeting tumor-associated macrophages (TAMs) to stimulate...

Abstract PS17-35: B7-H3 and B7-H4 expression in triple-negative breast cancer subtypes detected by RNA in situ hybridization and immunohistochemistry: Association with clinicopathological features and T-cell infiltration

Abstract Background: Triple-negative breast cancer (TNBC) is a heterogeneous group of cancer with dismal prognosis. B7 families can be promising targets for cancer immunotherapy in TNBC. Previously we have found increased expression of B7-H3 and B7-H4 mRNA and protein in breast cancer including TNBC. In an effort to discover therapeutic targets, TNBC has been further stratified into molecular subtypes. However, little is known about the clinical impact and value of B7-H3 and B7-H4 in TNBC subtypes. The purpose of this study was to evaluate the clinicopathologic characteristics of the B7-H3 and B7-H4 mRNA and protein expression according to the TNBC subset. Materials and methods: A tissue microarray was constructed from 186 patients with TNBC. B7-H3 and B7-H4 mRNA and protein expression were assessed by the RNAscope in situ hybridization (ISH) and immunohistochemistry. Immunohistochemistry for the TNBC molecular subtype-surrogate markers [cytokeratin 5/6 (CK5/6), CK14, epidermal growth factor receptor (EGFR), and androgen receptor (AR)], CD3, and CD8 was also performed. TNBC subtypes were classified into three subtypes: basal-like (BL), luminal AR (LAR), and unclassifiable type (UN). Results: Based on the immunohistochemical results, 186 TNBCs were classified into BL (n=120, 64.5%), LAR (n=10, 10.8%), and UN (n=46, 24.7%) subtypes. BL and UN subtypes were associated with younger age than the LAR subtype. B7-H3 mRNA and protein expressions were expressed in the tumor and stromal cells of the TNBCs. On the contrary, B7-H4 mRNA and protein expressions were only observed in the tumor cells. High tumor mRNA and protein expression of B7-H3 and B7-H4 were found in 49 of 175 (28.0%) and 121 of 176 (68.8) cases, and 92 of 174 (52.9%) and 66 of 176 (37.5%) cases, respectively. High stromal B7-H3 mRNA and protein expression were observed in 22 of 175 (12.6%) and 43 of 176 (24.4%) cases. High stromal B7-H4 mRNA and protein expression were not observed. B7-H3 and B7-H4 protein expression were closely correlated with their mRNA expression according to the tumor compartment. Tumor B7-H4 mRNA expression was associated with younger age at the initial diagnosis and molecular TNBC subtypes. Expression of B7-H3 mRNA and protein in the tumor cells negatively correlated with CD3+ and CD8+ T cell infiltration density in the tumor and/or stromal compartment of the TNBCs and its subtypes. High stromal B7-H3 mRNA expression was associated with poor disease-free and overall survival in the TNBCs and overall survival in the UN subtype. Stromal B7-H3 mRNA expression was independently associated with overall survival in the TNBCs and disease-free survival in the BL subtype. Conclusions: As prognostic factors, our results point to the importance of the expression of B7-H3 mRNA by the stromal cells in the TNBCs and the BL subtype. The inverse relationship between B7-H3 expression and CD3+ and CD8+ T lymphocyte infiltration may represent a promising target in the immunotherapy of the TNBCs, irrespective of its molecular subtypes. Citation Format: Ji Shin Lee, Nah Ihm Kim, Min Ho Park. B7-H3 and B7-H4 expression in triple-negative breast cancer subtypes detected by RNA in situ hybridization and immunohistochemistry: Association with clinicopathological features and T-cell infiltration [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS17-35.