Immunotherapy in breast cancer: An introduction

Epithelial Expressed B7-H4 Drives Differential Immunotherapy Response in Murine and Human Breast Cancer

Combinations of immune checkpoint inhibitors (ICI, including anti-PD-1/PD-L1) and chemotherapy have been FDA approved for metastatic and early-stage triple-negative breast cancer (TNBC), but most patients do not benefit. B7-H4 is a B7 family ligand with proposed immunosuppressive functions being explored as a cancer immunotherapy target and may be associated with anti-PD-L1 resistance. However, little is known about its regulation and effect on immune cell function in breast cancers. We assessed murine and human breast cancer cells to identify regulation mechanisms of B7-H4 in vitro. We used an immunocompetent anti-PD-L1-sensitive orthotopic mammary cancer model and induced ectopic expression of B7-H4. We assessed therapy response and transcriptional changes at baseline and under treatment with anti-PD-L1. We observed B7-H4 was highly associated with epithelial cell status and transcription factors and found to be regulated by PI3K activity. EMT6 tumors with cell-surface B7-H4 expression were more resistant to immunotherapy. In addition, tumor-infiltrating immune cells had reduced immune activation signaling based on transcriptomic analysis. Paradoxically, in human breast cancer, B7-H4 expression was associated with survival benefit for patients with metastatic TNBC treated with carboplatin plus anti-PD-L1 and was associated with no change in response or survival for patients with early breast cancer receiving chemotherapy plus anti-PD-1. While B7-H4 induces tumor resistance to anti-PD-L1 in murine models, there are alternative mechanisms of signaling and function in human cancers. In addition, the strong correlation of B7-H4 to epithelial cell markers suggests a potential regulatory mechanism of B7-H4 independent of PD-L1.

SIGNIFICANCE

This translational study confirms the association of B7-H4 expression with a cold immune microenvironment in breast cancer and offers preclinical studies demonstrating a potential role for B7-H4 in suppressing response to checkpoint therapy. However, analysis of two clinical trials with checkpoint inhibitors in the early and metastatic settings argue against B7-H4 as being a mechanism of clinical resistance to checkpoints, with clear implications for its candidacy as a therapeutic target.

Predictive value of stromal tumor-infiltrating lymphocytes in patients with breast cancer treated with neoadjuvant chemotherapy: A meta-analysis

BACKGROUND

The predictive value of tumor-infiltrating lymphocytes (TILs) in response to neoadjuvant chemotherapy (NAC) for breast cancer (BC) has received increasing attention. Here, a meta-analysis was conducted to evaluate the correlation between the expression of stromal TILs and pathological complete response (pCR) after NAC in BC patients.

METHODS

The PubMed, Embase, Cochrane Library, and Web of Science databases were searched online by using a combination of keywords and free words to screen literature on the expression of stromal TILs and pCR after NAC in patients with BC. The data were extracted and evaluated for quality. Relative risk (RR) was used to evaluate the relationship between the expression of stromal TILs before NAC and pCR in BC patients. Meta-analysis was performed with Review Manager 5.3 and STATA 14.0 software.

RESULTS

Eleven studies involving 6039 BC patients were included in the meta-analysis. The results showed a generally high expression of stromal TILs in BC patients, and the pCR rate after NAC in BC patients with a high expression of stromal TILs was significantly higher than that in BC patients with a low expression of stromal TILs [RR = 1.83, 95% confidence interval (CI): 1.69-1.97]. Subgroup analysis based on the molecular subtypes of BC showed that the pCR rate was significantly higher in patients with a high expression of stromal TILs in hormone receptor (HR)-positive BC [RR = 3.23, 95% CI: 2.43-4.30], human epidermal growth factor receptor 2 (HER-2)-positive BC [RR = 1.41, 95% CI: 1.25-1.60], and triple-negative BC [RR = 1.70, 95% CI: 1.53-1.90] than in those with a low expression of stromal TILs. Subgroup analysis based on expression threshold showed that the pCR rate was higher in patients with a high expression of stromal TILs than in patients with a low expression of stromal TILs at different expression thresholds (10% [RR = 1.99, 95% CI: 1.55-2.55], 20%/30% [RR = 1.57, 95% CI: 1.37-1.81], 50%/60% [RR = 1.91, 95% CI: 1.73-2.11].

CONCLUSION

TILs can be used as a predictor of pCR after NAC in patients with BC, and the appropriate high expression threshold of stromal TILs should be selected as the predictive value according to the molecular subtype of BC.

Plateletcrit is predictive of clinical outcome and prognosis for early-stage breast cancer: A retrospective cohort study based on propensity score matching

PURPOSE

Breast cancer (BC) is diagnosed as the most common cancer in women in 2022 according to the American Cancer Society. It is essential to detect early and treat early. Several studies have shown that some blood parameters have important predictive value for BC. In this study, we aim to explore whether some immune-associated blood parameters are relevant to disease-free survival (DFS) in early-stage BC.

METHODS

A single-center, regression cohort study of 1490 patients with early-stage BC in Shanghai Cancer Center was conducted from January 2008 to December 2016. The patients were matched according to the ratio of 1:1 based on Propensity Score Matching (PSM). All patients who experienced disease progression were matched successfully. Thus, 58 pairs of subjects were obtained. Matched blood parameters were evaluated by paired samples t-test or Wilcoxon signed-rank test. Factors with statistical difference were further evaluated by stratified COX regression model.

RESULTS

Univariate analysis showed differences in platelet-related parameters (PLT, PCT, and PLR) and NLR between the two matched groups. However, stratified COX regression analysis, which ruled out the confounding effects of multiple factors, found that only PCT had prognostic value in early BC patients at baseline and study endpoint. Meanwhile, platelet-related parameters (PLT, MPV) and NLR were different in the progressive group by self before and after comparison. However, the multiple-factor analysis showed that only the NLR had prognostic value. ROC curve analysis indicated that the best sensitivity (65.45%) and specificity (78.18%) were obtained when the baseline PCT was 0.225. The optimal sensitivity (70.91%) and specificity (65.45%) were obtained when the PCT of disease progression was 0.215. The Kaplan-Meier curve was used to calculate the DFS rate based on the critical values of the two groups.

CONCLUSIONS

Some blood parameters have value to predict DFS in early-stage BC patients, especially platelet-associated parameters.

A narrative review for radiation oncologists to implement preoperative partial breast irradiation

The strategy to anticipate radiotherapy (RT) before surgery, for breast cancer (BC) treatment, has recently generated a renewed interest. Historically, preoperative RT has remained confined either to highly selected patients, in the context of personalized therapy, or to clinical research protocols. Nevertheless, in the recent years, thanks to technological advances and increased tumor biology understanding, RT has undergone great changes that have also impacted the preoperative settings, embracing the modern approach to breast cancer. In particular, the reappraisal of preoperative RT can be viewed within the broader view of personalized and tailored medicine. In fact, preoperative accelerated partial breast irradiation (APBI) allows a more precise target delineation, with less variability in contouring among radiation oncologists, and a smaller treatment volume, possibly leading to lower toxicity and to dose escalation programs. The aim of the present review, which represents a benchmark study for the AIRC IG-23118, is to report available data on different technical aspects of preoperative RT including dosimetric studies, patient's selection and set-up, constraints, target delineation and clinical results. These data, along with the ones that will become available from ongoing studies, may inform the design of the future trials and representing a step toward a tailored APBI approach with the potential to challenge the current treatment paradigm in early-stage BC.Trial registration: The study is registered at clinicaltrials.gov (NCT04679454).

Identification of prognostic biomarkers of breast cancer based on the immune-related gene module

Breast cancer (BC) is highly malignant and its mortality rate remains high. The development of immunotherapy has gradually improved the prognosis and survival rate of patients. Therefore, identifying molecular markers concerned with BC immunity is of great importance for the treatment of this disease. The Cancer Genome Atlas-breast invasive carcinoma (TCGA-BRCA) was utilized as the training set while the BC expression dataset from the gene expression omnibus database was taken as the validation set here. Weighted gene co-expression network analysis combined with Pearson analysis and Tumor immune estimation resource (TIMER) was used to obtain immune cell-related hub gene module. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed on this module. Then, receiver operating characteristic curves combining Kaplan-Meier was used to evaluate the effectiveness of the model. Feature genes were screened and the independence of risk score was evaluated by univariate and multivariate Cox analyses. Differences in immune characteristics were analyzed via single-sample gene set enrichment analysis and CIBERSORT, and differences in gene mutation frequency were assessed via GenVisR analysis. Finally, the expression levels of prognostic feature genes in BC cells were validated by quantitative reverse transcription polymerase chain reaction (qRT-PCR). In this study, cell immune-related gene modules in TCGA-BRCA were successfully excavated, and a five-gene (TNFRSF14, NFKBIA, DLG3, IRF2, and CYP27A1) prognostic model was established. The prognostic model could effectively forecast the prognosis and survival rate of BC patients. The result showed that human leukocyte antigen-related proteins and macrophage M2 scores were remarkably highly expressed in the high-risk group, whereas CD8+ T cells, natural killer cells, M1, and other anti-tumor cells were lowly expressed. The model could be used as an independent prognostic factor to predict the prognosis of BC patients. The results of qRT-PCR validation were consistent with the results in the database, that is, except DLG3, the other four feature genes were lowly expressed in BC. The five-gene model established in this study can predict the prognostic and immune mode of BC patients effectively, which is anticipated to become a feasible molecular target for BC therapy.

Vaccines in Breast Cancer: Challenges and Breakthroughs

Breast cancer is a problem for women's health globally. Early detection techniques come in a variety of forms ranging from local to systemic and from non-invasive to invasive. The treatment of cancer has always been challenging despite the availability of a wide range of therapeutics. This is either due to the variable behaviour and heterogeneity of the proliferating cells and/or the individual's response towards the treatment applied. However, advancements in cancer biology and scientific technology have changed the course of the cancer treatment approach. This current review briefly encompasses the diagnostics, the latest and most recent breakthrough strategies and challenges, and the limitations in fighting breast cancer, emphasising the development of breast cancer vaccines. It also includes the filed/granted patents referring to the same aspects.

TIMELESS upregulates PD-L1 expression and exerts an immunosuppressive role in breast cancer

BACKGROUND

Upregulation of the PD-L1 (CD274) immune checkpoint ligand on the tumor surface facilitates tumor immune escape and limits the application of immunotherapy in various cancers, including breast cancer. However, the mechanisms underlying high PD-L1 levels in cancers are still poorly understood.

METHODS

Bioinformatics analyses and in vivo and in vitro experiments were carried out to assess the association between CD8⁺ T lymphocytes and TIMELESS (TIM) expression, and to discover the mechanisms of TIM, the transcription factor c-Myc, and PD-L1 in breast cancer cell lines.

RESULTS

The circadian gene TIM enhanced PD-L1 transcription and facilitated the aggressiveness and progression of breast cancer through the intrinsic and extrinsic roles of PD-L1 overexpression. Bioinformatic analyses of our RNA sequencing data in TIM-knockdown breast cancer cells and public transcriptomic datasets showed that TIM might play an immunosuppressive role in breast cancer. We found that TIM expression was inversely associated with CD8⁺ T lymphocyte infiltration in human breast cancer samples and subcutaneous tumor tissues. In vivo and in vitro experiments demonstrated that TIM knockdown increased CD8⁺ T lymphocyte antitumor activity. Furthermore, our results showed that TIM interacts with c-Myc to enhance the transcriptional capability of PD-L1 and facilitates the aggressiveness and progression of breast cancer through the intrinsic and extrinsic roles of PD-L1 overexpression. Moreover, public database analysis suggested that high TIM levels were positively related to PD-L1 inhibitor therapeutic response.

CONCLUSIONS

Mechanistically, we first found that TIM could upregulate PD-L1 by interacting with c-Myc to enhance the transcriptional capability of c-Myc to PD-L1. Altogether, our findings not only provide a novel therapeutic strategy to treat breast cancer by targeting the oncogenic effect of TIM but also indicate that TIM is a promising biomarker for predicting the benefit of anti-PD-L1 immunotherapy.

Circulating inflammatory cells in patients with metastatic breast cancer: Implications for treatment

Adaptive and innate immune cells play a crucial role as regulators of cancer development.

Inflammatory cells in blood flow seem to be involved in pro-tumor activities and contribute to breast cancer progression. Circulating lymphocyte ratios such as the platelet-lymphocytes ratio (PLR), the monocyte-lymphocyte ratio (MLR) and the neutrophil-lymphocyte ratio (NLR) are new reproducible, routinely feasible and cheap biomarkers of immune response. These indexes have been correlated to prognosis in many solid tumors and there is growing evidence on their clinical applicability as independent prognostic markers also for breast cancer.

In this review we give an overview of the possible value of lymphocytic indexes in advanced breast cancer prognosis and prediction of outcome. Furthermore, targeting the immune system appear to be a promising therapeutic strategy for breast cancer, especially macrophage-targeted therapies. Herein we present an overview of the ongoing clinical trials testing systemic inflammatory cells as therapeutic targets in breast cancer.

CTHRC1 is a Potential Prognostic Biomarker and Correlated with Macrophage Infiltration in Breast Cancer

Background

Tumor immune cell infiltration is closely associated with the occurrence and development of tumors. Collagen triple helix repeats containing 1 (CTHRC1), a regulator of collagen expression and cell migration, is involved in the metastasis and invasion of tumors. However, the role of CTHRC1 in breast cancer remains unclear. This study aimed to investigate the prognostic value of CTHRC1, and further explore its association with immune infiltration in breast cancer.

Methods

CTHRC1 expression pattern and prognostic value were analyzed using ONCOMINE, PrognoScan, GEPIA, and Kaplan–Meier Plotter databases. We then detected CTHRC1 mRNA levels in breast cancer tissues and paired normal breast tissues by Q-PCR. Subsequently, the University of California Santa Cruz (UCSC) database was used to determine the methylation status of CTHRC1. Furthermore, CTHRC1 mutations were investigated using the Catalogue of Somatic mutations in Cancer (COSMIC) and cBioPortal databases. We also assessed the correlation between CTHRC1 expression and immune cell infiltration using TIMER. In addition, The relationship of CTHRC1 expression with the immune marker sets of various immune cells was evaluated using GEPIA and TIMER.

Results

CTHRC1 was highly expressed in a variety of tumors, including breast cancer. Elevated CTHRC1 expression was related to a poor prognosis. Notably, CTHRC1 expression was significantly associated with macrophage infiltration, especially the immune infiltration gene marker set of M2. Copy number variations, DNA mutations and methylation states might be potential mechanisms for regulating CTHRC1 expression. Protein digestion and absorption, human papillomavirus infection, ECM-receptor interaction, focal adhesion, and PI3K-Akt signaling pathways were identified as the potential CTHRC1-driven signaling pathways.

Conclusion

These findings suggest that CTHRC1 could be a promising immune-related biomarker for the treatment of breast cancer patients.

Development of a Novel Immune-Related Gene Prognostic Index for Breast Cancer

Objective

To construct an immune-related gene prognostic index (IRGPI) for breast cancer (BC) and investigate its prognostic specificity and the molecular and immune characteristics.

Methods

BC hub genes were identified from The Cancer Genome Atlas and immune-related databases using weighted gene co-expression network analysis (WGCNA). IRGPI was constructed using univariate, LASSO, and multivariate regression analyses, and was validated with GSE58812 and GSE97342 in the Gene Expression Omnibus database (GEO). At the same time, we evaluated the predictive ability of IRGPI for different BC subtypes. Subsequently, the molecular and immune characteristics, clinical relevance, and benefits of immune checkpoint inhibitor treatment were analyzed for different IRGPI subgroups.

Results

IRGPI consisted of six genes: SOCS3, TCF7L2, TSLP NPR3, ANO6, and HMGB3. The IRGPI 1-, 5-, and 10-years area under curve (AUC) values were 0.635, 0.752, and 0.753, respectively, indicating that IRGPI has good potential in predicting the long-term survival of BC patients, consistent with the results in the GEO cohort. IRGPI showed good predictive power in four different breast cancer subtypes: ER positive, PR positive, HER2 positive and triple-negative (P<0.01). Compared with the low-IRGPI group, the high-IRGPI group had a worse prognosis and a lower degree of immune infiltrating cells (p < 0.05). IRGPI showed specificity in distinguishing age, TNM stage, ER, and HER2 statuses, and our study found that the high-IRGPI group had low tumor immune dysfunction and exclusion (TIDE), microsatellite instability (MSI), and T cell dysfunction scores (p < 0.05). In addition, compared with the TIDE and TIS models, showed that the AUCs of IRGPI were better during the 5-year follow-up.

Conclusion

IRGPI can be used as an independent prognostic indicator of breast cancer, providing a method for monitoring the long-term treatment of BC.

LyeTx I-b Peptide Attenuates Tumor Burden and Metastasis in a Mouse 4T1 Breast Cancer Model

Cationic anticancer peptides have exhibited potent anti-proliferative and anti-inflammatory effects in neoplastic illness conditions. LyeTx I-b is a synthetic peptide derived from Lycosa erythrognatha spider venom that previously showed antibiotic activity in vitro and in vivo. This study focused on the effects of LyeTxI-b on a 4T1 mouse mammary carcinoma model. Mice with a palpable tumor in the left flank were subcutaneously or intratumorally injected with LyeTx I-b (5 mg/kg), which significantly decreased the tumor volume and metastatic nodules. Histological analyses showed a large necrotic area in treated primary tumors compared to the control. LyeTxI-b reduced tumor growth and lung metastasis in the 4T1 mouse mammary carcinoma model with no signs of toxicity in healthy or cancerous mice. The mechanism of action of LyeTx I-b on the 4T1 mouse mammary carcinoma model was evaluated in vitro and is associated with induction of apoptosis and cell proliferation inhibition. Furthermore, LyeTx I-b seems to be an efficient regulator of the 4T1 tumor microenvironment by modulating several cytokines, such as TGF-β, TNF-α, IL-1β, IL-6, and IL-10, in primary tumor and lung, spleen, and brain. LyeTx I-b also plays a role in leukocytes rolling and adhesion into spinal cord microcirculation and in the number of circulating leukocytes. These data suggest a potent antineoplastic efficacy ofLyeTx I-b.

An Immune-Associated Genomic Signature Effectively Predicts Pathologic Complete Response to Neoadjuvant Paclitaxel and Anthracycline-Based Chemotherapy in Breast Cancer

Breast cancer is now the leading cause of cancer morbidity and mortality among women worldwide. Paclitaxel and anthracycline-based neoadjuvant chemotherapy is widely used for the treatment of breast cancer, but its sensitivity remains difficult to predict for clinical use. In our study, a LASSO logistic regression method was applied to develop a genomic classifier for predicting pathologic complete response (pCR) to neoadjuvant chemotherapy in breast cancer. The predictive accuracy of the signature classifier was further evaluated using four other independent test sets. Also, functional enrichment analysis of genes in the signature was performed, and the correlations between the prediction score of the signature classifier and immune characteristics were explored. We found a 25-gene signature classifier through the modeling, which showed a strong ability to predict pCR to neoadjuvant chemotherapy in breast cancer. For T/FAC-based training and test sets, and a T/AC-based test set, the AUC of the signature classifier is 1.0, 0.9071, 0.9683, 0.9151, and 0.7350, respectively, indicating that it has good predictive ability for both T/FAC and T/AC schemes. The multivariate model showed that 25-gene signature was far superior to other clinical parameters as independent predictor. Functional enrichment analysis indicated that genes in the signature are mainly enriched in immune-related biological processes. The prediction score of the classifier was significantly positively correlated with the immune score. There were also significant differences in immune cell types between pCR and residual disease (RD) samples. Conclusively, we developed a 25-gene signature classifier that can effectively predict pCR to paclitaxel and anthracycline-based neoadjuvant chemotherapy in breast cancer. Our study also suggests that the immune ecosystem is actively involved in modulating clinical response to neoadjuvant chemotherapy and is beneficial to patient outcomes.

A seven-nuclear receptor-based prognostic signature in breast cancer

BACKGROUND

Breast cancer (BRCA) is a malignant cancer that threatened the life of female with unsatisfactory prognosis. The aim of this study was to identify prognostic nuclear receptors (NRs) signature of BRCA.

METHODS

BRCA patient samples were collected from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database. Consensus clustering analysis, univariate Cox regression analysis and the least absolute shrinkage and selection operator (LASSO) Cox regression analysis were performed to evaluate, select NRs as prognostic factors and build Risk Score model. GSEA analysis was explored to check signaling differences between High- and Low-Risk group. Nomogram model basing on age and Risk Score was established to predict the 1-, 3- and 5-year survival. Model performance was assessed by a time-dependent receiver operating characteristic (ROC) curve and calibration plot. CIBERSORT, ESTIMATE and TIMER algorithm were introduced to evaluate the immune landscape.

RESULTS

NR3C1, NR4A3, THRA, RXRG, NR2F6, NR1D2 and RORB were optimized as a prognostic signature for BRCA. This seven-NR-based Risk Score could effectively predict overall survival status. The area under the curve (AUC) of 1-, 3- and 5-year overall survival are 0.702, 0.734 and 0.722 in TCGA training cohort, and 0.630, 0.721 and 0.823 in GEO validation cohort, respectively. Calibration plot demonstrated satisfactory agreement between predictive and observed outcomes. Nomogram model worked well on predicting survival probabilities. Multiple cancer-related pathways were highly enriched in High-Risk group. High- and Low-Risk groups showed significant differed immune cell infiltration. There exists an obvious connection between Risk Score and immune checkpoints LAG3, PD1 and TIM3.

CONCLUSION

The seven-NR-based Risk Score represents a promising signature for estimating overall survival in patients with BRCA, and is correlated with the immune microenvironment.

Protein citrullination as a source of cancer neoantigens

BACKGROUND

Citrulline post-translational modification of proteins is mediated by protein arginine deiminase (PADI) family members and has been associated with autoimmune diseases. The role of PADI-citrullinome in immune response in cancer has not been evaluated. We hypothesized that PADI-mediated citrullinome is a source of neoantigens in cancer that induces immune response.

METHODS

Protein expression of PADI family members was evaluated in 196 cancer cell lines by means of indepth proteomic profiling. Gene expression was assessed using messenger RNA data sets from The Cancer Genome Atlas. Immunohistochemical analysis of PADI2 and peptidyl-citrulline was performed using breast cancer tissue sections. Citrullinated 12-34-mer peptides in the putative Major Histocompatibility Complex-II (MHC-II) binding range were profiled in breast cancer cell lines to investigate the relationship between protein citrullination and antigen presentation. We further evaluated immunoglobulin-bound citrullinome by mass spectrometry using 156 patients with breast cancer and 113 cancer-free controls.

RESULTS

Proteomic and gene expression analyses revealed PADI2 to be highly expressed in several cancer types including breast cancer. Immunohistochemical analysis of 422 breast tumor tissues revealed increased expression of PADI2 in ER- tumors (p<0.0001); PADI2 protein expression was positively correlated (p<0.0001) with peptidyl-citrulline staining. PADI2 expression exhibited strong positive correlations with a B cell immune signature and with MHC-II-bound citrullinated peptides. Increased circulating citrullinated antigen-antibody complexes occurred among newly diagnosed breast cancer cases relative to controls (p=0.0012).

CONCLUSIONS

An immune response associated with citrullinome is a rich source of neoantigens in breast cancer with a potential for diagnostic and therapeutic applications.

Sunitinib Combined with Th1 Cytokines Potentiates Apoptosis in Human Breast Cancer Cells and Suppresses Tumor Growth in a Murine Model of HER-2pos Breast Cancer

Although immune-based therapies have made remarkable inroads in cancer treatment, they usually must be combined with standard treatment modalities, including cytotoxic drugs, to achieve maximal clinical benefits. As immunotherapies are further advanced and refined, considerable efforts will be required to identify combination therapies that will maximize clinical responses while simultaneously decreasing the unpleasant and sometimes life-threatening side effects of standard therapy. Over the last two decades, evidence has emerged that Th1 cytokines can play a central role in protective antitumor immunity and that combinations of Th1 cytokines can induce senescence and apoptosis in cancer cells. To explore the possibility of combining targeted drugs with Th1-polarizing vaccines, we undertook a study to examine the impact of combining Th1 cytokines with the relatively broad-spectrum receptor tyrosine kinase antagonist, sunitinib. We found that when a panel of five phenotypically diverse human breast cancer cell lines was subjected to treatment with sunitinib plus recombinant Th1 cytokines IFN-γ and TNF-α, synergistic effects were observed across a number of parameters including different aspects of apoptotic cell death. Interestingly, sunitinib was found to have a profoundly suppressive effect of T cell's capacity to secrete IFN-γ, indicating that in vivo use of this drug may hinder robust Th1 responses. Nonetheless, this suppression was circumvented in a mouse model of HER-2^pos breast disease by supplying recombinant interferon-gamma to achieve a combination therapy significantly more potent than either agent.

Phase-Transformation Nanoparticle-Mediated Sonodynamic Therapy: An Effective Modality to Enhance Anti-Tumor Immune Response by Inducing Immunogenic Cell Death in Breast Cancer

Purpose

Immunologically quiescent of breast cancer cells has been recognized as the key impediment for the breast cancer immunotherapy. In this study, we aimed to investigate the role of nanoparticle-mediated sonodynamic therapy (SDT) in promoting anti-tumor immune of breast cancer cells and its potential immune mechanisms.

Materials and Methods

The phase-transformation nanoparticles (LIP-PFH nanoparticles) were in-house prepared and its physiochemical characters were detected. The CCK-8 assay, apoptosis analysis and Balb/c tumor model establishment were used to explore the anti-tumor effect of LIP-PFH nanoparticles triggered by low-intensity focused ultrasound (LIFU) both in vitro and in vivo. Flow cytometry and immunohistochemistry of CD4⁺T, CD8⁺T, CD8⁺PD-1⁺T in blood, spleen and tumor tissue were performed to represent the change of immune response. Detection of immunogenic cell death (ICD) markers was examined to study the potential mechanisms.

Results

LIP-PFH nanoparticles triggered by LIFU could inhibit the proliferation and promote the apoptosis of 4T1 cells both in vitro and in vivo. CD4⁺T and CD8⁺T cell subsets were significantly increased in blood, spleen and tumor tissue, meanwhile CD8⁺PD-1⁺T cells were reduced, indicating enhancement of anti-tumor immune response of breast cancer cells in the nanoparticle-mediated SDT group. Detection of ICD markers (ATP, high-mobility group box B1, and calreticulin) and flow cytometric analysis of dendritic cell (DC) maturity further showed that the nanoparticle-mediated SDT can promote DC maturation to increase the proportion of cytotoxic T cells by inducing ICD of breast cancer cells.

Conclusion

The therapy of nanoparticles-mediated SDT can effectively enhance anti-tumor immune response of breast cancer.

A novel immune-related prognostic index for predicting breast cancer overall survival

PURPOSE

To find immune-related genes with prognostic value in breast cancer, and construct a prognostic risk assessment model to make a more accurate assessment. Moreover, looking for potential immune markers for breast cancer immunotherapy.

METHODS

The breast cancer (BC) data were retrieved from The Cancer Genome Atlas (TCGA) database as a training set. Through the Weighted gene co-expression network analysis (WGCNA), Kaplan-Meier (KM) analysis, lasso regression analysis and stepwise backward Cox regression analysis, screening for prognosis-related immune genes, a prognostic index was built, and external validation with two data sets of Gene Expression Omnibus (GEO) database was performed. Transcription factor (TF) regulatory network was constructed to identify key transcription factors that regulate prognostic immune genes. Gene set enrichment analysis (GSEA) was used to explore the signal pathways differences between high and low-risk groups, estimate package and TIMER database were used to evaluate the relationship between risk score and tumor immune microenvironment.

RESULTS

We obtained 10 prognosis-related immune genes, and the index showed accurate prognostic value. We also identified 7 prognostic transcription factors. Multiple signaling pathways that inhibit tumor progression were enriched in the low-risk group, and risk score was significantly negatively related to the degree of immune infiltration and the expression level of immune checkpoint genes.

CONCLUSION

We successfully constructed an independent prognostic index, which not only has a stronger predictive ability than the tumor pathological stage, but also can reflect the immune infiltration of breast cancer patients.

Identification of Five Immune-Related lncRNAs Predicting Survival and Tumor Microenvironment Characteristics in Breast Cancer

A common cancer in females, breast cancer (BRCA) mortality has been recently reduced; however, the prognosis of BRCA patients remains poor. This study attempted to develop prognostic immune-related long noncoding RNAs (lncRNAs) for BRCA and identify the effects of these lncRNAs on the tumor microenvironment (TME). Gene expression data from The Cancer Genome Atlas (TCGA) database were collected in order to select differentially expressed lncRNAs. Immune-related lncRNAs were downloaded from the ImmLnc database, where 316 immune-related lncRNAs were identified, 12 of which were found to be significantly related to the prognosis of BRCA patients. Multivariate cox regression analysis was then applied to construct prognostic immune-related lncRNAs as the risk model, including C6orf99, LINC00987, SIAH2-AS1, LINC01010, and ELOVL2-AS1. High-risk and low-risk groups were distinguished according to the median of immune-related risk scores. Accordingly, the overall survival (OS) in the high-risk group was observed to be shorter than that in the low-risk group. qRT-PCR analysis demonstrated that lncRNA expression levels in BRCA cell lines were in basic agreement with predictions except for LINC00987. By validating numerous clinical samples, lncRNA C6orf99 was shown to be highly expressed in the advanced stage, while LINC01010 and SIAH2-AS1 decreased in the advanced T-stage and M-stage. Moreover, the expression of LINC0098 was found to be significantly decreased among the groups (>50 years old). Gene set enrichment analysis (GSEA) was applied to analyze the cancer hallmarks and immunological characteristics of the high-risk and low-risk groups. Importantly, the TIMER database demonstrated that this immune-related lncRNA risk model for breast cancer is related to the infiltration of immune cells. In conclusion, the results indicated that five immune-related lncRNAs could be used as a prognostic model and may even accelerate immunotherapy for BRCA patients.

Recent progress in immunotherapy of breast cancer targeting the human epidermal growth factor receptor 2 (HER2)

OBJECTIVE

Breast cancer is responsible for most of the cancer-induced deaths in women around the world. The current review will discuss different approaches of targeting HER2, an epidermal growth factor overexpressed in 30% of breast cancer cases.

DATA SOURCES

We conducted a search on Pubmed and Scopus databases to find studies relevant to HER2+ breast cancers and targeting HER2 as means of immunotherapy. Out of 1043 articles, 105 studies were included in this review.

DATA SUMMARY

As well as the introduction of HER2 and breast cancer subtypes, we discussed various aspects of HER2-targeting immunotherapy including monoclonal antibodies, Antibody-drug conjugates (ADCs), Chimeric Antigen Receptor (CAR) T-cells and vaccines.

CONCLUSIONS

Despite several ways of controlling breast cancer, the need to investigate new drugs and approaches seems to be much significant as this cancer still has a heavy burden on people's health and survival.

The recent advances of PD-1 and PD-L1 checkpoint signaling inhibition for breast cancer immunotherapy

Over the past decade, there has been sustained research activity on programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) immune checkpoint inhibitors for breast cancer (BC) immunotherapy. Several clinical studies have demonstrated the anti-tumor efficacy of monotherapy drugs targeting PD-1 and PD-L1 checkpoint signaling in BC. Besides, the combination of anti-PD-1/PD-L1 agents with other inhibitors, including poly-adenosine diphosphate-ribose polymerase (PARP) inhibitors, vaccines, mitogen-activated protein kinase (MEK) inhibitors, and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) inhibitors are being investigated to improve drug efficacy. These trials have performed well and have shown better and more sustainable therapeutic responses. As follows, the purpose of this review is to discuss the recent advances in BC immunotherapy targeting the inhibition of PD-1/PD-L1 immune checkpoint signaling, when recommended as a monotherapy or in conjunction with other treatments. We look forward to providing new insights into the current state of BC research and the future direction of PD-1/PD-L1 immune checkpoint signaling.

Chemical features of blood-borne TRG CDR3s associated with an increased overall survival in breast cancer

PURPOSE

Immunogenomics and earlier, pioneering studies, particularly by Whiteside and colleagues, have indicated a positive role for B-cells in breast cancer, as well as a positive role for gamma-delta T-cells. However, these studies have been completely limited to assessing breast cancer tumor tissue.

METHODS AND RESULTS

Our analyses here has shown that blood-borne T-cell receptor gamma (TRG) chain sequences were associated with greater overall survival, of particular note due to the comparative longevity of primary breast cancer patients, whereby assessments of disease-free, but rarely overall survival parameters are possible. Additional immunogenomics approaches narrowed the overall survival correlations to specific, TRG complementarity determining region-3, amino acid (AA) sequence chemical features, independently of many common, confounding variables in the breast cancer setting, such as estrogen or progesterone receptor status.

CONCLUSIONS

These results are discussed in the context of patient age and with regard to potential antigenic targets, based on the chemistry of the TRG CDR3 AA sequences associated with the higher survival rates.

Breast cancer-induced immune suppression in the sentinel lymph node is effectively countered by CpG-B in conjunction with inhibition of the JAK2/STAT3 pathway

BACKGROUND

We previously showed selectively hampered activation of lymph node-resident (LNR) dendritic cell (DC) subsets in the breast cancer (BrC) sentinel lymph node (SLN) to precede a state of profound T cell anergy. Reactivating these DC subsets by intratumoral delivery of the Toll-like receptor-9 (TLR9) agonist CpG-B could potentially offer a promising immune therapeutic strategy to combat this immune suppression and prevent disease spread. Unfortunately, CpG-B can limit its own immune stimulatory activity through direct TLR9-mediated activation of signal transducer and activator of transcription 3 (STAT3), pinpointed as a key regulator of immune suppression in the tumor microenvironment. Here, we have investigated whether in vitro exposure to CpG-B, with or without simultaneous inhibition of STAT3 signaling, could overcome immune suppression in BrC SLN.

METHODS

Immune modulatory effects of CpG-B (CPG7909) with or without the JAK2/STAT3 inhibitor (STAT3i) AG490 were assessed in ex vivo cultured BrC SLN-derived single-cell suspensions (N=29). Multiparameter flow cytometric analyses were conducted for DC and T cell subset characterization and assessment of (intracellular) cytokine profiles. T cell reactivity against the BrC-associated antigen Mammaglobin-A was determined by means of interferon-γ ELISPOT assay.

RESULTS

Although CpG-B alone induced activation of all DC subsets, combined inhibition of the JAK2/STAT3 pathway resulted in superior DC maturation (ie, increased CD83 expression), with most profound activation and maturation of LNR DC subsets. Furthermore, combined CpG-B and JAK2/STAT3 inhibition promoted Th1 skewing by counterbalancing the CpG-induced Th2/regulatory T cell response and significantly enhanced Mammaglobin-A specific T cell reactivity.

CONCLUSION

Ex vivo immune modulation of the SLN by CpG-B and simultaneous JAK2/STAT3 inhibition can effectively overcome BrC-induced immune suppression by preferential activation of LNR DC, ultimately restoring type 1-mediated antitumor immunity, thereby securing a BrC-specific T cell response. These findings provide a clear rationale for clinical exploration of SLN-immune potentiation through local CpG/STAT3i administration in patients with BrC.

An immune-related prognostic signature for predicting breast cancer recurrence

Breast cancer (BC) is the most common cancer among women worldwide and is the second leading cause of cancer‐related deaths in women. Increasing evidence has validated the vital role of the immune system in BC development and recurrence. In this study, we identified an immune‐related prognostic signature of BRCA that could help delineate risk scores of poor outcome for each patient. This prognostic signature comprised information on five danger genes—TSLP, BIRC5, S100B, MDK, and S100P—and three protect genes RARRES3, BLNK, and ACO1. Kaplan‐Meier survival curve showed that patients classified as low‐risk according to optimum cut‐off risk score had better prognosis than those identified within the high‐risk group. ROC analysis indicated that the identified prognostic signature had excellent diagnostic efficiency for predicting 3‐ and 5‐years relapse‐free survival (RFS). Multivariate Cox regression analysis proved that the prognostic signature is independent of other clinical parameters. Stratification analysis demonstrated that the prognostic signature can be used to predict the RFS of BC patients within the same clinical subgroup. We also developed a nomogram to predict the RFS of patients. The calibration plots exhibited outstanding performance. The validation sets (GSE21653, GSE20711, and GSE88770) were used to external validation. More convincingly, the real time RT‐PCR results of clinical samples demonstrated that danger genes were significantly upregulated in BC samples, whereas protect genes were downregulated. In conclusion, we developed and validated an immune‐related prognostic signature, which exhibited excellent diagnostic efficiency in predicting the recurrence of BC, and will help to make personalized treatment decisions for patients at different risk score.

A Rosetta Stone for Breast Cancer: Prognostic Value and Dynamic Regulation of Neutrophil in Tumor Microenvironment

Increasing evidence has revealed that the initiation and progression of breast cancer are greatly affected by the immune environment. Neutrophils are the most abundant leucocytes in circulation and act as the spearhead in inflammation, including in breast cancer. Circulating neutrophils are closely related to the prognosis of breast cancer patients, and tumor-infiltrating neutrophils have varied functions at different stages of breast cancer, such as antitumor or tumor-promoting neutrophils, which are termed N1 and N2 neutrophils, respectively. In this review, we will discuss the utility of circulating neutrophils for predicting prognosis and therapeutic efficacy and the underlying mechanisms of their chemotaxis, the dynamic regulation of their antitumor or protumor functions and their different spatial distributions in tumor microenvironment. Finally, we also discuss the possibility of targeting neutrophils as a therapeutic strategy in breast cancer.

SOLTI-1503 PROMETEO TRIAL: combination of talimogene laherparepvec with atezolizumab in early breast cancer

New treatment strategies such as immune checkpoint inhibitors and oncolytic viruses are opening new possibilities in cancer therapy. Preliminary results in melanoma and other tumors showed that the combination of talimogene laherparepvec with an anti-PD-1/PD-L1 or anti-CTLA4 has greater efficacy than either therapy alone, without additional safety concerns beyond those expected for each agent. The presence of residual cancer after neoadjuvant chemotherapy in early breast cancer patients is an unmet medical need. SOLTI-1503 PROMETEO is a window of opportunity trial, which evaluates the combination of talimogene laherparepvec in combination with atezolizumab in women with operable HER2-negative breast cancer who present residual disease after neoadjuvant chemotherapy. The primary end point is the rate of residual cancer burden 0/1. Clinical Trial Registration: NCT03802604.

Novel HLA-A2 restricted antigenic peptide derivatives with high affinity for the treatment of breast cancer expressing NY-ESO-1

Tumor immunotherapy based on specific tumor antigen has become the focus for breast cancer, and research into cancer/testes antigens (CTA) is progressing. As an important member in the CTA, NY-ESO-1 plays a crucial role in the treatment and prognosis of breast cancer. In this study, we aimed to improve the binding ability to MHC by designing and synthesizing stable NY-ESO-1-derived peptides, based on NetMHC 4.0 webserver (http://www.cbs.dtu.dk/services/NetMHC/) and HLP webserver (http://crdd.osdd.net/raghava/hlp/pep_both.htm). Moreover, after modification of the lead compound, affinity of the peptides to human leukocyte antigen-A2 (HLA-A2) was determined by a flow cytometry and an inverted fluorescence microscope in T2 cells that show high expression of HLA-A2. The results demonstrated that the affinity of peptides II-4 and II-10 to HLA-A2 was significantly better when compared to others (II-Lead, II-1 ~ II-3, II-5 ~ II-9, II-11 ~ II-15). Further studies indicated that II-4 and II-10, especially II-4, significantly promoted the maturation of HLA-A2-positive human peripheral blood-derived dendritic cells (DCs) from morphology and surface markers, the activation of CD8 + T lymphocytes, and the type-specific killing effect on HLA-A2⁺/NY-ESO-1⁺ MDA-MB-231 cells. Molecular docking studies suggested a strong interaction between peptide II-4 and HLA-A2, thereby indicating that the II-4 is a promising candidate with antigenic potential in the field of immunotherapy that needs more studies.

Development and validation of a stromal immune phenotype classifier for predicting immune activity and prognosis in triple-negative breast cancer

Our study aims to construct a prognosis-related immune phenotype classifier for predicting clinical prognosis and immune activity in triple-negative breast cancer (TNBC). A total of 237 patients with TNBC from Sun Yat-sen University Cancer Center (SYSUCC) and 533 patients with TNBC from public datasets were included in our study. A stromal immune quantified index was generated with a LASSO Cox regression model based on five prognosis-related immune cells evaluated by CIBERSORT or IHC and was used to determine immune phenotypes. Immune features were evaluated in the samples before chemotherapy. A total of 119 patients in the SYSUCC training cohort were classified into immune Phenotypes A and B according to the density of stromal CD4+ T cells, γδ T cells, monocytes, M1 macrophages and M2 macrophages. Phenotype A predicted better survival than Phenotype B, and the classification was further validated in the testing cohort of 118 patients and the validation cohort of 533 patients. In the combined cohort, significant differences were found in Phenotype A compared to Phenotype B for the 5-year overall survival (83.5% vs 65.8%, respectively, P < .01) and the 5-year disease-free survival (87.3% vs 76.0%, respectively, P < .01). In Phenotype A, immune-related pathways were significantly enriched, and a higher level of immune checkpoint molecules, including PD-L1, PD-1 and CTLA-4, could be observed. The immune phenotype classification was an independent prognostic indicator for TNBC and might serve as a potential predictor for immune activity within the tumor microenvironment.

Pharmacological Inhibition of Necroptosis Promotes Human Breast Cancer Cell Proliferation and Metastasis

BACKGROUND

Breast cancer remains a great threat to females worldwide. As a recently defined programmed cell death pathway that associates with immune activation, RIP1/RIP3/MLKL necroptosis signaling has been implicated in a variety of diseases. The present study aimed to investigate the role of RIP1/RIP3/MLKL signaling in breast cancer cell proliferation and metastasis in vivo and in vitro.

METHODS

Western blot and quantitative real-time PCR were performed to evaluate the activation of necroptosis signaling in clinical human breast cancer tissues. Correlation of necroptosis signaling markers with clinicopathological parameters was statistically assessed. Cell viability assay, colony formation assay, wound healing assay, and transwell migration and invasion assays were performed to investigate the effects of necroptosis inhibition on breast cancer cell proliferation and metastasis.

RESULTS

Clinical breast cancer tissues showed significantly higher levels of tumor necrosis factor alpha (TNFα), RIP1, RIP3 and MLKL at both mRNA and protein levels as compared with their paired non-cancerous tissues. Phosphorylation of RIP3 and MLKL was also remarkably provoked. Statistics showed that both RIP1 and MLKL positively correlated with cancer parameters such as N-cadherin (p=0.002 for RIP1 and p=0.021 for MLKL) and Ki67 (p=0.031 for RIP1 and p=0.05 for MLKL). The MLKL expression level significantly correlated with tumor size (p=0.001) and the proliferation indicator Ki67 (p=0.018). In addition, pharmacological inhibition of the necroptosis signaling using necrostatin-1 promoted breast cancer cell proliferation and colony formation by approximately 50%. Blockade of necroptosis signaling also accelerated wound healing process and cell transmigration in breast cancer cells.

CONCLUSION

Our results suggested that pharmacological inhibition of necroptosis promoted breast cancer cell proliferation and metastasis. Modulation of tumor cell necroptosis might represent a novel strategy as to breast cancer treatment.

Predictive Value of Lymphocyte-Related Blood Parameters at the Time Point of Lymphocyte Nadir During Radiotherapy in Breast Cancer

Purpose

Various reports found a relationship between lymphocyte-related blood parameters (LRBP), including absolute lymphocyte counts (ALC), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) and prognosis of breast cancer. Most of the studies focused on LRBP pre-treatment. Seldom have studies focused on LRBP during radiotherapy. We intended to perform a retrospective cohort study on the prognostic value of LRBP at the time point of lowest ALC during radiotherapy for breast cancer.

Patients and methods

A total of 158 female patients were included in radiotherapy group because of the strict limitation standards of complete routine blood test results at pre-treatment and pre-operation, and at least once a week during radiotherapy. Besides 221 patients, including the 158 patients of radiotherapy group, were adopted in pre-treatment group and pre-operation group.

Results

ALC and PLR at the time point of lowest ALC during radiotherapy are prognostic predictors of breast cancer, and lower ALC and higher PLR are independent significant predictors of poor DFS. Besides, lower ALC, higher NLR and higher PLR at both pre-treatment and pre-operation were found to be independent variables for predicting poor DFS.

Conclusion

LRBP at pre-treatment, pre-operation, and during radiotherapy may serve as predictors of outcomes of breast cancer.

PD-L1 status in breast cancer: Current view and perspectives

Breast cancer was traditionally not considered a particularly immunogenic tumor. However, recent developments have shown that some aggressive triple-negative breast cancers are immunogenic, exhibit a resistance to chemotherapy and have a poor prognosis. These cancers have been shown to express molecules identified as targets for immunotherapy. Despite the advances, the challenges are many, and include identifying the patients that may benefit from immunotherapy. The best methods to analyze these samples and to evaluate immunogenicity are also major challenges. Therefore, the most accurate and reliable assessment of immune cells as potential targets is one of the most important aims in the current research in breast immunotherapy. In the present review, we briefly discuss the mechanisms of the regulation of checkpoint inhibitors (PD-1/PD-L1) in breast cancer and explore the predictive aspects in the PD-L1 testing.

ILC2s: New Actors in Tumor Immunity

Innate lymphoid cells (ILCs) represent the most recently identified family of innate lymphocytes that act as first responders, maintaining tissue homeostasis and protecting epithelial barriers. In the last few years, group 2 ILCs (ILC2s) have emerged as key regulators in several immunological processes such as asthma and allergy. Whilst ILC2s are currently being evaluated as novel targets for immunotherapy in these diseases, their involvement in tumor immunity has only recently begun to be deciphered. Here, we provide a comprehensive overview of the pleiotropic roles of ILC2s in different tumor settings. Furthermore, we discuss how different therapeutic approaches targeting ILC2s could improve the efficacy of current tumor immunotherapies.

Hirsutella sinensis Inhibits Lewis Lung Cancer via Tumor Microenvironment Effector T Cells in Mice

Hirsutella sinensis fungus (HSF) is an artificial substitute of the well-known medicine Cordyceps sinensis with similar beneficial effects in humans. We previously found that HSF can regulate immune function and inhibit tumor growth; however, the mechanisms involved in these effects were still unclear. Accordingly, in this study, we investigated the effects of HSF on immune cell subsets in the tumor microenvironment in mice. The results showed that HSF inhibited Lewis lung cancer growth, alleviated abnormalities in routine blood tests, and enhanced tumor-infiltrating T cells, particularly the proportion of effector CD8[Formula: see text] T cells. In addition, HSF also ameliorated the immune-suppressive microenvironment and decreased the proportions of regulatory T cell and myeloid-derived suppressor cell populations. To confirm the effects of HSF on promotion of effector CD8[Formula: see text] T-cell production, we further evaluated changes in postoperative metastasis following treatment with HSF. Indeed, orthotopic lung metastasis was significantly suppressed, and survival times were increased in HSF-treated mice. Taken together, our findings suggested that HSF inhibited Lewis lung cancer by enhancing the population of effective CD8[Formula: see text] T cells.

Identification of tumor-reactive B cells and systemic IgG in breast cancer based on clonal frequency in the sentinel lymph node

A better understanding of antitumor immune responses is the key to advancing the field of cancer immunotherapy. Endogenous immunity in cancer patients, such as circulating anticancer antibodies or tumor-reactive B cells, has been historically yet incompletely described. Here, we demonstrate that tumor-draining (sentinel) lymph node (SN) is a rich source for tumor-reactive B cells that give rise to systemic IgG anticancer antibodies circulating in the bloodstream of breast cancer patients. Using a synergistic combination of high-throughput B-cell sequencing and quantitative immunoproteomics, we describe the prospective identification of tumor-reactive SN B cells (based on clonal frequency) and also demonstrate an unequivocal link between affinity-matured expanded B-cell clones in the SN and antitumor IgG in the blood. This technology could facilitate the discovery of antitumor antibody therapeutics and conceivably identify novel tumor antigens. Lastly, these findings highlight the unique and specialized niche the SN can fill in the advancement of cancer immunotherapy.

Impact of the Tumor Microenvironment on Tumor-Infiltrating Lymphocytes: Focus on Breast Cancer

Immunotherapy is revolutionizing cancer care across disciplines. The original success of immune checkpoint blockade in melanoma has already been translated to Food and Drug Administration-approved therapies in a number of other cancers, and a large number of clinical trials are underway in many other disease types, including breast cancer. Here, we review the basic requirements for a successful antitumor immune response, with a focus on the metabolic and physical barriers encountered by lymphocytes entering breast tumors. We also review recent clinical trials of immunotherapy in breast cancer and provide a number of interesting questions that will need to be answered for successful breast cancer immunotherapy.

Treating breast cancer with cell-based approaches: an overview

INTRODUCTION

Breast cancer is the most common malignancy in women. Despite there being considerable progress in the treatment of this disease, metastatic dissemination is still considered an incurable condition at the present time, causing 500,000 deaths worldwide every year. Although most of the research efforts have been focused on pharmacological approaches, over the last three decades, the use of bone marrow and peripheral blood-derived cell therapy approaches have been attempted and developed. Areas covered: This review will briefly address cell therapy for breast cancer, including autologous stem cell transplantations for overcoming the myelosuppressive effects of high-dose chemotherapy, allogeneic stem cell transplants and adoptive immunotherapy using bone-marrow derived T-cells. Expert opinion: The treatment of breast cancer using bone marrow or peripheral-blood derived cells has evolved from a supportive care approach to allow dose escalation of conventional chemotherapy to a therapeutic strategy aimed at eliciting immune cell mediated anticancer immunity. This latter principle has led to the development of adoptive immunotherapies, either with 'natural' or genetically engineered effectors, which are being intensively investigated for their great potential against several solid tumors, including breast cancer.

Breast Cancer Vaccines: New Insights

Breast cancer (BC) is a persistent global challenge for its high frequency in women (although it seldom occurs in men), due to the large diffusion of risk factors and gene mutations, and for its peculiar biology and microenvironment. To date, BC can benefit from different therapeutic strategies involving surgery, ablation, chemotherapy, radiotherapy, and more specific approaches such as hormone therapy and the administration of various substances impairing cancer growth, aggressivity, and recurrence with different modalities. Despite these relatively wide chances, also used in combinatory protocols, relevant mortality and relapse rates, often associated with resistant phenotypes, stress the need for a personalized-medicine based on prompting the patient's immune system (IS) against cancer cells. BC immunogenicity was latterly proven, so the whole immunotherapy field for BC is still at a very early stage. This immunotherapeutic approach exploits both the high specificity of adaptive immune response and the immunological memory. This review is focused on some of the majorly relevant BC vaccines available (NeuVax, AVX901, and INO-1400), providing a description of the more promising clinical trials. The efficacy of cancer vaccines highly depends on the patient's IS, and a wide optimization is needed in terms of targets' selection, drug design and combinations, dose finding, protocol structuring, and patients' recruitment; moreover, new standards are being discussed for the outcome evaluation. However, early-phases excellent results suggest that the manipulation of the IS via specific vaccines is a highly attractive approach for BC.