Feasibility study of personalized peptide vaccination for metastatic recurrent triple-negative breast cancer patients

Neoantigens and cancer-testis antigens as promising vaccine candidates for triple-negative breast cancer: Delivery strategies and clinical trials

Immunotherapy is gaining prominence as a promising strategy for treating triple-negative breast cancer (TNBC). Neoantigens (neoAgs) and cancer-testis antigens (CTAs) are tumor-specific targets originating from somatic mutations and epigenetic changes in cancer cells. These antigens hold great promise for personalized cancer vaccines, as supported by preclinical and early clinical evidence in TNBC. This review delves into the potential of neoAgs and CTAs as vaccine candidates, emphasizing diverse strategies and delivery approaches. It also highlights the current status of vaccination modalities undergoing clinical trials in TNBC therapy. A comprehensive understanding of neoAgs, CTAs, vaccination strategies, and innovative delivery methods is crucial for optimizing neoAg-based immunotherapies in clinical practice.

Advances in immunotherapy for triple-negative breast cancer

BACKGROUND

Immunotherapy has recently emerged as a treatment strategy which stimulates the human immune system to kill tumor cells. Tumor immunotherapy is based on immune editing, which enhances the antigenicity of tumor cells and increases the tumoricidal effect of immune cells. It also suppresses immunosuppressive molecules, activates or restores immune system function, enhances anti-tumor immune responses, and inhibits the growth f tumor cell. This offers the possibility of reducing mortality in triple-negative breast cancer (TNBC).

MAIN BODY

Immunotherapy approaches for TNBC have been diversified in recent years, with breakthroughs in the treatment of this entity. Research on immune checkpoint inhibitors (ICIs) has made it possible to identify different molecular subtypes and formulate individualized immunotherapy schedules. This review highlights the unique tumor microenvironment of TNBC and integrates and analyzes the advances in ICI therapy. It also discusses strategies for the combination of ICIs with chemotherapy, radiation therapy, targeted therapy, and emerging treatment methods such as nanotechnology, ribonucleic acid vaccines, and gene therapy. Currently, numerous ongoing or completed clinical trials are exploring the utilization of immunotherapy in conjunction with existing treatment modalities for TNBC. The objective of these investigations is to assess the effectiveness of various combined immunotherapy approaches and determine the most effective treatment regimens for patients with TNBC.

CONCLUSION

This review provides insights into the approaches used to overcome drug resistance in immunotherapy, and explores the directions of immunotherapy development in the treatment of TNBC.

Peptide Vaccines as Therapeutic and Prophylactic Agents for Female-Specific Cancers: The Current Landscape

Breast and gynecologic cancers are significant global threats to women's health and those living with the disease require lifelong physical, financial, and social support from their families, healthcare providers, and society as a whole. Cancer vaccines offer a promising means of inducing long-lasting immune response against the disease. Among various types of cancer vaccines available, peptide vaccines offer an effective strategy to elicit specific anti-tumor immune responses. Peptide vaccines have been developed based on tumor associated antigens (TAAs) and tumor specific neoantigens which can also be of viral origin. Molecular alterations in HER2 and non-HER2 genes are established to be involved in the pathogenesis of female-specific cancers and hence were exploited for the development of peptide vaccines against these diseases, most of which are in the latter stages of clinical trials. However, prophylactic vaccines for viral induced cancers, especially those against Human Papillomavirus (HPV) infection are well established. This review discusses therapeutic and prophylactic approaches for various types of female-specific cancers such as breast cancer and gynecologic cancers with special emphasis on peptide vaccines. We also present a pipeline for the design and evaluation of a multiepitope peptide vaccine that can be active against female-specific cancers.

Evaluation of the Immunological Response of Childhood Cancer Patients Treated with a Personalized Peptide Vaccine for Refractory Soft Tissue Tumor: A Four-Case Series

This case series aimed to evaluate the peptide-specific immunoglobulin G (IgG) response, clinical effectiveness, and the safety of a personalized peptide vaccine (PPV) in four children with refractory solid cancer. Although the pre-vaccination IgG responses were suppressed, IgG levels against the vaccinated peptides after 12 vaccinations were increased in all three cases who received at least 12 vaccinations. Vaccination-related adverse effects were grade 1 injection-site local skin lesions. One patient, whose diagnosis was relapsed rhabdomyosarcoma, remains in sustained remission after 37 months. Although the pre-vaccination immune response in this patient was low, IgG levels against 2 of the 4 peptide vaccines were increased after the sixth vaccination, followed by a strong increase at the eighteenth vaccination against all 4 peptides, with a >100-fold increase vs. 2 peptides. The remaining three patients exhibited progressive disease and eventually died of their original cancer. The results of the current case series suggest that in cases of childhood solid tumors, when the tumor is controlled at the time of entry PPV may have some consolidation effect. Therefore, PPV could be a new immunotherapy modality for refractory childhood solid tumors.

Impact of the Cancer Cell Secretome in Driving Breast Cancer Progression

Breast cancer is a complex and heterogeneous disease resulting from the accumulation of genetic and epigenetic alterations in breast epithelial cells. Despite remarkable progress in diagnosis and treatment, breast cancer continues to be the most prevalent cancer affecting women worldwide. Recent research has uncovered a compelling link between breast cancer onset and the extracellular environment enveloping tumor cells. The complex network of proteins secreted by cancer cells and other cellular components within the tumor microenvironment has emerged as a critical player in driving the disease's metastatic properties. Specifically, the proteins released by the tumor cells termed the secretome, can significantly influence the progression and metastasis of breast cancer. The breast cancer cell secretome promotes tumorigenesis through its ability to modulate growth-associated signaling pathways, reshaping the tumor microenvironment, supporting pre-metastatic niche formation, and facilitating immunosurveillance evasion. Additionally, the secretome has been shown to play a crucial role in drug resistance development, making it an attractive target for cancer therapy. Understanding the intricate role of the cancer cell secretome in breast cancer progression will provide new insights into the underlying mechanisms of this disease and aid in the development of more innovative therapeutic interventions. Hence, this review provides a nuanced analysis of the impact of the cancer cell secretome on breast cancer progression, elucidates the complex reciprocal interaction with the components of the tumor microenvironment and highlights emerging therapeutic opportunities for targeting the constituents of the secretome.

Breast cancer heterogeneity and its implication in personalized precision therapy

Breast cancer heterogeneity determines cancer progression, treatment effects, and prognosis. However, the precise mechanism for this heterogeneity remains unknown owing to its complexity. Here, we summarize the origins of breast cancer heterogeneity and its influence on disease progression, recurrence, and therapeutic resistance. We review the possible mechanisms of heterogeneity and the research methods used to analyze it. We also highlight the importance of cell interactions for the origins of breast cancer heterogeneity, which can be further categorized into cooperative and competitive interactions. Finally, we provide new insights into precise individual treatments based on heterogeneity.

Cancer Vaccines for Triple-Negative Breast Cancer: A Systematic Review

Triple-negative breast cancer (TNBC) is the subtype of breast cancer with the poorest outcomes, and is associated with a high risk of relapse and metastasis. The treatment choices for this malignancy have been confined to conventional chemotherapeutic agents, due to a lack of expression of the canonical molecular targets. Immunotherapy has been recently changing the treatment paradigm for many types of tumors, and the approach of evoking active immune responses in the milieu of breast tumors through cancer vaccines has been introduced as one of the most novel immunotherapeutic approaches. Accordingly, a number of vaccines for the treatment or prevention of recurrence have been developed and are currently being studied in TNBC patients, while none have yet received any approvals. To elucidate the efficacy and safety of these vaccines, we performed a systematic review of the available literature on the topic. After searching the PubMed, Scopus, Web of Science, Embase, Cochrane CENTRAL, and Google Scholar databases, a total of 5701 results were obtained, from which 42 clinical studies were eventually included based on the predefined criteria. The overall quality of the included studies was acceptable. However, due to a lack of reporting outcomes of survival or progression in some studies (which were presented as conference abstracts) as well as the heterogeneity of the reported outcomes and study designs, we were not able to carry out a meta-analysis. A total of 32 different vaccines have so far been evaluated in TNBC patients, with the majority belonging to the peptide-based vaccine type. The other vaccines were in the cell or nucleic acid (RNA/DNA)-based categories. Most vaccines proved to be safe with low-grade, local adverse events and could efficiently evoke cellular immune responses; however, most trials were not able to demonstrate significant improvements in clinical indices of efficacy. This is in part due to the limited number of randomized studies, as well as the limited TNBC population of each trial. However, due to the encouraging results of the currently published trials, we anticipate that this strategy could show its potential through larger, phase III randomized studies in the near future.

Immunotherapy in triple negative breast cancer: beyond checkpoint inhibitors

The development of immunotherapy agents has revolutionized the field of oncology. The only FDA-approved immunotherapeutic approach in breast cancer consists of immune checkpoint inhibitors, yet several novel immune-modulatory strategies are being actively studied and appear promising. Innovative immunotherapeutic strategies are urgently needed in triple negative breast cancer (TNBC), a subtype of breast cancer known for its poor prognosis and its resistance to conventional treatments. TNBC is more primed to respond to immunotherapy given the presence of more tumor infiltrating lymphocytes, higher PD-L1 expression, and higher tumor mutation burden relative to the other breast cancer subtypes, and therefore, immuno-oncology represents a key area of promise for TNBC research. The aim of this review is to highlight current data and ongoing efforts to establish the safety and efficacy of immunotherapeutic approaches beyond checkpoint inhibitors in TNBC.

Peptide-Based Vaccines in Clinical Phases and New Potential Therapeutic Targets as a New Approach for Breast Cancer: A Review

Breast cancer is the leading cause of death in women from 20 to 59 years old. The conventional treatment includes surgery, chemotherapy, hormonal therapy, and immunotherapy. This immunotherapy is based on administering monoclonal therapeutic antibodies (passive) or vaccines (active) with therapeutic purposes. Several types of vaccines could be used as potential treatments for cancer, including whole-cell, DNA, RNA, and peptide-based vaccines. Peptides used to develop vaccines are derived from tumor-associated antigens or tumor-specific antigens, such as HER-2, MUC1, ErbB2, CEA, FRα, MAGE A1, A3, and A10, NY-ESO-1, among others. Peptide-based vaccines provide some advantages, such as low cost, purity of the antigen, and the induction of humoral and cellular immune response. In this review, we explore the different types of vaccines against breast cancer with a specific focus on the description of peptide-based vaccines, their composition, immune response induction, and the description of new potential therapeutic targets.

Potential association factors for developing effective peptide-based cancer vaccines

Peptide-based cancer vaccines have been shown to boost immune systems to kill tumor cells in cancer patients. However, designing an effective T cell epitope peptide-based cancer vaccine still remains a challenge and is a major hurdle for the application of cancer vaccines. In this study, we constructed for the first time a library of peptide-based cancer vaccines and their clinical attributes, named CancerVaccine (https://peptidecancervaccine.weebly.com/). To investigate the association factors that influence the effectiveness of cancer vaccines, these peptide-based cancer vaccines were classified into high (HCR) and low (LCR) clinical responses based on their clinical efficacy. Our study highlights that modified peptides derived from artificially modified proteins are suitable as cancer vaccines, especially for melanoma. It may be possible to advance cancer vaccines by screening for HLA class II affinity peptides may be an effective therapeutic strategy. In addition, the treatment regimen has the potential to influence the clinical response of a cancer vaccine, and Montanide ISA-51 might be an effective adjuvant. Finally, we constructed a high sensitivity and specificity machine learning model to assist in designing peptide-based cancer vaccines capable of providing high clinical responses. Together, our findings illustrate that a high clinical response following peptide-based cancer vaccination is correlated with the right type of peptide, the appropriate adjuvant, and a matched HLA allele, as well as an appropriate treatment regimen. This study would allow for enhanced development of cancer vaccines.

Recent Progress on Therapeutic Vaccines for Breast Cancer

Breast cancer remains the most frequently diagnosed malignancy worldwide. Advanced breast cancer is still an incurable disease mainly because of its heterogeneity and limited immunogenicity. The great success of cancer immunotherapy is paving the way for a new era in cancer treatment, and therapeutic cancer vaccination is an area of interest. Vaccine targets include tumor-associated antigens and tumor-specific antigens. Immune responses differ in different vaccine delivery platforms. Next-generation sequencing technologies and computational analysis have recently made personalized vaccination possible. However, only a few cases benefiting from neoantigen-based treatment have been reported in breast cancer, and more attention has been given to overexpressed antigen-based treatment, especially human epidermal growth factor 2-derived peptide vaccines. Here, we discuss recent advancements in therapeutic vaccines for breast cancer and highlight near-term opportunities for moving forward.

Breast Cancer Treatments: Updates and New Challenges

Breast cancer (BC) is the most frequent cancer diagnosed in women worldwide. This heterogeneous disease can be classified into four molecular subtypes (luminal A, luminal B, HER2 and triple-negative breast cancer (TNBC)) according to the expression of the estrogen receptor (ER) and the progesterone receptor (PR), and the overexpression of the human epidermal growth factor receptor 2 (HER2). Current BC treatments target these receptors (endocrine and anti-HER2 therapies) as a personalized treatment. Along with chemotherapy and radiotherapy, these therapies can have severe adverse effects and patients can develop resistance to these agents. Moreover, TNBC do not have standardized treatments. Hence, a deeper understanding of the development of new treatments that are more specific and effective in treating each BC subgroup is key. New approaches have recently emerged such as immunotherapy, conjugated antibodies, and targeting other metabolic pathways. This review summarizes current BC treatments and explores the new treatment strategies from a personalized therapy perspective and the resulting challenges.

Progress and challenges of immunotherapy in triple-negative breast cancer

Triple-negative breast cancer (TNBC), a subtype of breast cancer, is defined as lacking estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2) expression. Compared with other subtypes in breast cancer, TNBC is more likely to recur and metastasize, with a lower survival rate. Due to the absence of definitive targets, there was limited novel therapeutic interventions and chemotherapy remained the primary treatment in the past decades. Following the development of immune checkpoint inhibition (ICI) in solid tumors and validation of the immunogenicity in TNBC, immunotherapy has attracted more and more attentions. On basis of accumulating clinical studies, we reviewed the current progress targeting different immune checkpoints in several-lines treatment for TNBC, including programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) inhibitors, cytotoxic T-lymphocyte associated antigen-4 (CTLA-4) inhibitor, and other novel immunotherapeutic approaches (e.g., individualized peptide vaccine, cancer-testis antigen (CTA), new antigen vaccine, RNA vaccine and chimeric antigen receptor modified T cells (CAR-T)). In order to improve the survival outcome of TNBC populations, we further discussed potential predictive biomarkers for immunotherapy (e.g., PD-L1 expression, tumor mutational burden (TMB), tumor-infiltrating lymphocytes (TILs), microsatellite instability (MSI)/mismatch repair (MMR) deficiency) and challenges in the future treatment of TNBC.

Therapeutic Cancer Vaccination with Immunopeptidomics-Discovered Antigens Confers Protective Antitumor Efficacy

Knowledge of clinically targetable tumor antigens is becoming vital for broader design and utility of therapeutic cancer vaccines. This information is obtained reliably by directly interrogating the MHC-I presented peptide ligands, the immunopeptidome, with state-of-the-art mass spectrometry. Our manuscript describes direct identification of novel tumor antigens for an aggressive triple-negative breast cancer model. Immunopeptidome profiling revealed 2481 unique antigens, among them a novel ERV antigen originating from an endogenous retrovirus element. The clinical benefit and tumor control potential of the identified tumor antigens and ERV antigen were studied in a preclinical model using two vaccine platforms and therapeutic settings. Prominent control of established tumors was achieved using an oncolytic adenovirus platform designed for flexible and specific tumor targeting, namely PeptiCRAd. Our study presents a pipeline integrating immunopeptidome analysis-driven antigen discovery with a therapeutic cancer vaccine platform for improved personalized oncolytic immunotherapy.

Plasma level of prostate related-antigen peptide-reactive IgG is a prognostic factor of patients with breast cancer treated with personalized peptide vaccines

The present study assessed plasma IgG in patients with metastatic recurrent breast cancer (mrBC) that is reactive to various T-cell epitope peptides of prostate-related antigens (PRAs), such as prostate-specific antigen, prostate-specific membrane antigen and prostate acid phosphatase. Patients were treated with personalized peptide vaccines (PPVs) which were selected and administered from a panel of candidate peptides based on human leukocyte antigen-types and prevaccination IgG levels to each peptide. The peptide panel consisted of 27 cytotoxic T-lymphocyte-epitope peptides derived from tumor-associated antigens, not including PRA. PRA peptides and peptide panels were retrospectively analyzed in 77 PPV-treated patients. The results revealed that PRA reactive IgG levels were increased after vaccination in 31 of the 97 patients included in the present study. Although there was no significant association between anti-PRA peptide levels and progression-free survival (PFS) or overall survival, anti-PRA peptide levels were significantly associated with PFS (P=0.009) in estrogen-receptor positive (ER+) patients with cancer. The results suggested that plasma anti-PRA IgG levels may be a useful prognostic marker for monitoring PPVs, particularly for ER+ patients with mrBC (trial registration no. from the UMIN Clinical Trials Registry, UMIN000001844).

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.

Investigation of factors associated with reduced clinical benefits of personalized peptide vaccination for pancreatic cancer

The aim of the present study was to determine the factors associated with reduced clinical benefits of personalized peptide vaccination (PPV) for pancreatic cancer. Phase II PPV clinical trials comprising 309 (8 non-advanced and 301 advanced-stage) patients with pancreatic cancer were conducted. Two to four peptides were selected among a set of 31 different peptides as vaccine candidates for personalized peptide vaccination based on human leukocyte antigen types and preexisting peptide-specific IgG levels, and subcutaneously injected. The selected peptides were subcutaneously injected. Of the 309 patients, 81 failed to complete the 1st PPV cycle due to rapid disease progression, and their median overall survival [2.1 months; 95% confidence interval (CI), 1.8-2.7] was significantly shorter than that of the remaining 228 patients (8.4 months; 95% CI, 8.4-9.9; P<0.01). ‘Immune boosting’ was defined when IgG levels before vaccination increased more than 2-fold after vaccination. Immune boosting was observed in the majority of patients with PPV irrespective of whether or not they received concomitant chemotherapy. Additionally, patients demonstrating immune boosting exhibited longer survival rates. Although the positive-response rates and peptide-specific IgG levels in pre- and post-vaccination samples differed among the 31 peptides, patients exhibiting immune boosting in response to each of the vaccinated peptides demonstrated longer survival times. Pre-vaccination factors associated with reduced clinical benefits were high c-reactive protein (CRP) levels, high neutrophil counts, lower lymphocyte and red blood cell counts, advanced disease stage and the greater number of chemotherapy courses prior to the PPV treatment. The post-vaccination factors associated with lower clinical benefits were PPV monotherapy and lower levels of immune boosting. In conclusion, pre-vaccination inflammatory signatures, rather than pre- or post-vaccination immunological signatures, were associated with reduced clinical benefits of personalized peptide vaccination (PPV) for pancreatic cancer.

Efficacy of cancer vaccines in selected gynaecological breast and ovarian cancers: A 20-year systematic review and meta-analysis

BACKGROUND

Therapeutic cancer vaccination is an area of interest, even though promising efficacy has not been demonstrated so far.

DESIGN

A systematic review and meta-analysis was conducted to evaluate vaccines' efficacy on breast cancer (BC) and ovarian cancer (OC) patients. Our search was based on the PubMed electronic database, from 1st January 2000 to 4th February 2020.

OBJECTIVE

response rate (ORR) was the primary end-point of interest, while progression-free survival (PFS), overall survival (OS) and toxicity were secondary end-points. Analysis was performed separately for BC and OC patients. Pooled ORRs were estimated by fixed or random effects models, depending on the detected degree of heterogeneity, for all studies with more than five patients. Subgroup analyses by vaccine type and treatment schema as well as sensitivity analyses, were implemented.

RESULTS

Among 315 articles initially identified, 67 were eligible for our meta-analysis (BC: 46, 1698 patients; OC: 32, 426 patients; where both BC/OC in 11). Dendritic-cell and peptide vaccines were found in more studies, 6/10 BC and 10/13 OC studies, respectively. In our primary BC analysis (21 studies; 428 patients), the pooled ORR estimate was 9% (95%CI[5%,13%]). The primary OC analysis (12 studies; 182 patients), yielded pooled ORR estimate of 4% (95%CI[1%,7%]). Similar were the results derived in sensitivity analyses. No statistically significant differences were detected by vaccine type or treatment schema. Median PFS was 2.6 months (95% confidence interval (CI)[1.9,2.9]) and 13.0 months (95%CI[8.5,16.3]) for BC and OC respectively, while corresponding median OS was 24.8 months (95%CI[15.0,46.0]) and 39.0 months (95%CI[31.0,49.0]). In almost all cases, the observed toxicity was only moderate.

CONCLUSION

Despite their modest results in terms of ORR, therapeutic vaccines in the last 20 years display relatively long survival rates and low toxicity. Since a plethora of different approaches have been tested, a better understanding of the underlying mechanisms is needed in order to further improve vaccine efficacy.

A Screened GPR1 Peptide Exerts Antitumor Effects on Triple-Negative Breast Cancer

The adipokine chemerin has been considered an important regulator of tumor immune surveillance. Chemerin recruits leukocytes through the receptor CMKLR1 to improve clinical outcomes of tumors and overall patient survival, but the role of GPR1 in tumors has not been widely investigated. Here, we found that GPR1 expression is elevated in breast cancer-especially triple-negative breast cancer (TNBC) tissues and cell lines. Herein, we screened a phage display peptide library to identify LRH7-G5, a peptide antagonist that blocks chemerin/GPR1 signaling. This peptide performed as an anticancer agent to suppress the proliferation of the TNBC cell lines MDA-MB-231 and HCC1937 but has little effect on T47D cells. LRH7-G5 treatment significantly blocked tumor growth in a TNBC cell-bearing orthotopic mouse model. Last, our results showed that this peptide's antitumor role is mediated through the PI3K/AKT signaling pathway. In conclusion, these data collectively suggest that the chemerin receptor GPR1 is a novel target for controlling TNBC progression and establish peptide LRH7-G5 as a new therapeutic agent for suppressing TNBC tumor growth.

Early phase II study of mixed 19-peptide vaccine monotherapy for refractory triple-negative breast cancer

We undertook an early phase II study of mixed 19‐peptide cancer vaccine monotherapy for 14 advanced metastatic triple‐negative breast cancer (mTNBC) patients refractory to systemic chemotherapy to develop a new type of cancer vaccine. The treatment protocol consisted of a weekly vaccination for 6 weeks, and there were no severe adverse events related to the vaccination throughout the trial. Increase of peptide‐specific IgG against the vaccinated human leukocyte antigen‐matched peptides, but not against the nonmatched peptides, was positively correlated with overall survival (OS) (P < .01). The median OS was 11.5 or 24.4 months in all 14 patients or the 10 patients who completed the vaccination. The patients with lower C‐reactive protein levels or 3 or fewer systemic chemotherapies were favorable candidates for this treatment. Advancement of this therapy to the next stage of study could be warranted based on the safety and immune boosting determined herein (clinical trial registration number: UMIN000014616).

Immunotherapy in Triple-Negative Breast Cancer: Present and Future

Purpose of Review

Immunotherapy is emerging as an effective treatment option for metastatic triple-negative breast cancer. In this review, we summarize clinical data of immunotherapy in triple-negative breast cancer and comment on future directions in the field.

Recent Findings

IMpassion130 was a phase III trial that demonstrated progression-free survival benefit, and potentially overall survival benefit, of first-line chemotherapy (nab-paclitaxel) plus anti-programmed death ligand 1 (PD-L1) atezolizumab, among PD-L1-positive metastatic triple-negative breast cancers. Studies are ongoing to evaluate other combination therapies with immune checkpoint blockade in TNBC, and to evaluate efficacy in PD-L1-negative tumors and in later lines of therapy.

Summary

Immunotherapy is now a standard option in the treatment of triple-negative breast cancer. Ongoing trials may expand the degree of clinical benefit. Further work is ongoing to identify novel predictive biomarkers, which in the future may enable a personalized approach of combination immunotherapy.

Peptide-based materials for cancer immunotherapy

Peptide-based materials hold great promise as immunotherapeutic agents for the treatment of many malignant cancers. Extensive studies have focused on the development of peptide-based cancer vaccines and delivery systems by mimicking the functional domains of proteins with highly specific immuno-regulatory functions or tumor cells fate controls. However, a systemic understanding of the interactions between the different peptides and immune systems remains unknown. This review describes the role of peptides in regulating the functions of the innate and adaptive immune systems and provides a comprehensive focus on the design, categories, and applications of peptide-based cancer vaccines. By elucidating the impacts of peptide length and formulations on their immunogenicity, peptide-based immunomodulating agents can be better utilized and dramatic breakthroughs may also be realized. Moreover, some critical challenges for translating peptides into large-scale synthesis, safe delivery, and efficient cancer immunotherapy are posed to improve the next-generation peptide-based immunotherapy.

Immune precision medicine for cancer: a novel insight based on the efficiency of immune effector cells

Cancer cell growth is associated with immune surveillance failure. Nowadays, restoring the desired immune response against cancer cells remains a major therapeutic strategy. Due to the recent advances in biological knowledge, efficient therapeutic tools have been developed to support the best bio-clinical approaches for immune precision therapy. One of the most important successes in immune therapy is represented by the applicational use of monoclonal antibodies, particularly the use of rituximab for B-cell lymphoproliferative disorders. More recently, other monoclonal antibodies have been developed, to inhibit immune checkpoints within the tumor microenvironment that limit immune suppression, or to enhance some immune functions with immune adjuvants through different targets such as Toll-receptor agonists. The aim is to inhibit cancer proliferation by the diminishing/elimination of cancer residual cells and clinically improving the response duration with no or few adverse effects. This effect is supported by enhancing the number, functions, and activity of the immune effector cells, including the natural killer (NK) lymphocytes, NKT-lymphocytes, γδ T-lymphocytes, cytotoxic T-lymphocytes, directly or indirectly through vaccines particularly with neoantigens, and by lowering the functions of the immune suppressive cells. Beyond these new therapeutics and their personalized usage, new considerations have to be taken into account, such as epigenetic regulation particularly from microbiota, evaluation of transversal functions, particularly cellular metabolism, and consideration to the clinical consequences at the body level. The aim of this review is to discuss some practical aspects of immune therapy, giving to clinicians the concept of immune effector cells balancing between control and tolerance. Immunological precision medicine is a combination of modern biological knowledge and clinical therapeutic decisions in a global vision of the patient.

Immunological therapy: A novel thriving area for triple-negative breast cancer treatment

Triple-negative breast cancer (TNBC) refers to cancers that are low in expression of the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). TNBC tends to behave more aggressively than other types of breast cancer. Unlike other breast cancer subtypes (ie, ER-positive, HER2-positive subtypes), there are no approved targeted treatments available, other than the administration of chemotherapy. Immunotherapy is a new kind of treatment approach for TNBC when compared with the surgical treatment, chemotherapy, endocrine therapy, and molecular targeting therapy. The present article reviews the research progresses of immunotherapy for TNBC in recent years. The full text structure covers molecular classification of TNBC, active immunotherapy of TNBC, passive immunotherapy of TNBC, oncolytic immunotherapy and the prospect of immunotherapy for TNBC.

Immunotherapeutic interventions of Triple Negative Breast Cancer

Triple Negative Breast Cancer (TNBC) is a highly heterogeneous subtype of breast cancer that lacks the expression of oestrogen receptors, progesterone receptors and human epidermal growth factor receptor 2. Although TNBC is sensitive to chemotherapy, the overall outcomes of TNBC are worse than for other breast cancers, and TNBC is still one of the most fatal diseases for women. With the discovery of antigens specifically expressed in TNBC cells and the developing technology of monoclonal antibodies, chimeric antigen receptors and cancer vaccines, immunotherapy is emerging as a novel promising option for TNBC. This review is mainly focused on the tumour microenvironment and host immunity, Triple Negative Breast Cancer and the clinical treatment of TNBC, novel therapies for cancer and immunotherapy for TNBC, and the future outlook for the treatment for TNBC and the interplay between the therapies, including immune checkpoint inhibitors, combination of immune checkpoint inhibitors with targeted treatments in TNBC, adoptive cell therapy, cancer vaccines. The review also highlights recent reports on the synergistic effects of immunotherapy and chemotherapy, antibody-drug conjugates, and exosomes, as potential multifunctional therapeutic agents in TNBC.

Immunotherapy for triple-negative breast cancer: Existing challenges and exciting prospects

Patients with breast tumors that do not express the estrogen receptor, the progesterone receptor, nor Her-2/neu are hence termed "triple negatives", and generally have a poor prognosis, with high rates of systemic recurrence and refractoriness to conventional therapy regardless of the choice of adjuvant treatment. Thus, more effective therapeutic options are sorely needed for triple-negative breast cancer (TNBC), which occurs in approximately 20% of diagnosed breast cancers. In recent years, exploiting intrinsic mechanisms of the host immune system to eradicate cancer cells has achieved impressive success, and the advances in immunotherapy have yielded potential new therapeutic strategies for the treatment of this devastating subtype of breast cancer. It is anticipated that the responses initiated by immunotherapeutic interventions will explicitly target and annihilate tumor cells, while at the same time spare normal cells. Various immunotherapeutic approaches have been already developed and tested, which include the blockade of immune checkpoints using neutralizing or blocking antibodies, induction of cytotoxic T lymphocytes (CTLs), adoptive cell transfer-based therapy, and modulation of the tumor microenvironment to enhance the activity of CTLs. One of the most important areas of breast cancer research today is understanding the immune features and profiles of TNBC and devising novel immune-modulatory strategies to tackling TNBC, a subtype of breast cancer notorious for its poor prognosis and its imperviousness to conventional treatments. On the optimal side, one can anticipate that novel, effective, and personalized immunotherapy for TNBC will soon achieve more success and impact clinical treatment of this disease which afflicts approximately 20% of patients with breast cancer. In the present review, we highlight the current progress and encouraging developments in cancer immunotherapy, with a goal to discuss the challenges and to provide future perspectives on how to exploit a variety of new immunotherapeutic approaches including checkpoint inhibitors and neoadjuvant immunotherapy for the treatment of patients with TNBC.

Predictive factors of the tumor immunological microenvironment for long-term follow-up in early stage breast cancer

The aim of this research was to investigate the correlation of immunologic factors in the tumor environment of breast cancer, using immunohistological staining to evaluate the expression of programmed death 1/programmed death ligand 1 (PD-1/PD-L1), phosphatase and tensin homolog (PTEN), tumor infiltrating lymphocytes (TILs), and macrophages, and to analyze the association between the immunologic factors and clinical outcome for patients with early stage breast cancer (EBC). A total of 97 EBC patients who underwent standard surgery were investigated. Expression of PD-1/PD-L1 and PTEN and the density of CD3+ TILs, CD8+ TILs, and CD163+ macrophages were evaluated by immunohistochemical analysis. The association between the immunologic factors and clinical outcome was statistically analyzed. The density of CD3+ TILs, CD8+ TILs, and CD163+ macrophages and non-expression of PTEN was significantly higher in cases of triple negative breast cancer. CD8+ TIL density and CD8+ /PD-L1+ expression were predictive factors for disease-free survival and overall survival (OS). Human epidermal growth factor 2 (HER2)-positive patients with PTEN expression and luminal/HER2-negative patients without PD-L1 expression had significantly longer OS compared to patients without PTEN expression (P = 0.049) and with PD-L1 expression (P = 0.036), respectively. Furthermore, patients with PD-L1+ /CD8+ expression had worse median progression-free survival (P = 0.022) and median OS (P = 0.037) compared with patients without PD-L1+ /CD8+ expression. The CD3+ TILs, CD8+ TILs, and CD163+ macrophages were shown to infiltrate the tumor area of EBC. In particular, triple negative breast cancer had a higher rate of TIL infiltration within the tumor environment. Expression of PTEN and lack of PD-L1 expression were associated with favorable survival in HER2-positive and luminal/HER2-negative EBC patients, respectively. The PD-L1 expression combined with CD8+ density was significantly associated with an aggressive clinical outcome.

The Clinical Significance of CD169-Positive Lymph Node Macrophage in Patients with Breast Cancer

The immune status of patients can impact on the clinical course of cancer. Lymph node (LN) macrophages play critical roles in anti-cancer immunity via the activation of cytotoxic T-lymphocytes (CTLs). In this study, the prognostic significance of CD169⁺ LN macrophages was examined in patients with breast cancer. For this purpose the number of CD169⁺ cells and their ratio relative to total macrophages (CD68⁺) in regional LNs (RLNs), as well as the number of CD8⁺ CTLs in tumor tissues, were investigated using immunohistochemistry of paraffin-embedded tissue samples from 146 patients with breast cancer. The association of these data with clinicopathological factors was then analyzed. The number of cells positive for the pan-macrophage marker CD68 remained relatively uniform, while the number of CD169⁺ cells varied across all cases. Moreover, a high density of CD169⁺ cells correlated with early clinical stage and no LN metastasis, while a higher CD169⁺ to CD68⁺ ratio was significantly associated with small tumor size and a low Ki-67⁺ rate. There was also a significant correlation between the number of CD8⁺ CTLs and that of CD169⁺ macrophages in high grade breast cancer cases with a Ki-67 index greater than 40%. However, neither the density nor the ratio of CD169⁺ cells, nor the density of CD8⁺ CTLs, were associated with relapse-free survival, distant relapse-free survival, or breast cancer-specific survival. These findings suggest that CD169⁺ macrophages in RLNs might be a useful marker for assessing clinical stage, including LN states, in patients with breast cancer.

Triple-negative breast cancer: advancements in characterization and treatment approach

PURPOSE OF REVIEW

Triple-negative breast cancer (TNBC) comprises 15-20% of all breast cancer and is defined by the lack of estrogen and progesterone receptor expression and absence of human epidermal growth factor receptor 2 amplification. Compared with patients with hormone receptor positive or Her-2 positive breast cancer, patients with TNBC are more commonly young (age <50 years), African-American and have a higher incidence of BRCA1/2 mutations. The clinical course is frequently characterized by early relapse and poor overall survival. The TNBC phenotype is impervious to therapies commonly used in other breast cancer subtypes, including hormonal therapy and Her-2 receptor antagonism. Cytotoxic chemotherapy remains the only approved treatment. With its aggressive clinical course and paucity of effective treatment options, TNBC represents an unmet clinical need. This review will focus on updates of the biologic underpinnings of TNBC and the associated treatment advances.

RECENT FINDINGS

Numerous advancements have been made toward understanding the biologic framework of TNBC. Gene expression profiling has revealed six clinically relevant subsets of TNBC. Further study has demonstrated a portion of TNBC exhibits a strong immune gene signature. Lastly, it is now appreciated that a subgroup of sporadic TNBC shares biologic characteristics with BRCA1/2-mutated breast cancer, notably homologous repair deficiency. Recent studies focus on incorporation of platinum salts and new combinations of conventional chemotherapeutic agents. Targeted agents, including poly-ADP ribose polymerase inhibitors, antiangiogenic agents, phosphoinositide 3-kinase (PI3K) pathway inhibitors, and androgen antagonist are also being evaluated. Most recently, checkpoint inhibitors have demonstrated a modest degree of activity in a subset of TNBC.

SUMMARY

These discoveries are informing novel treatment paradigms and identification of correlative biomarkers in TNBC. Improved understanding of the biologic heterogeneity of TNBC is allowing for a more effective and individualized approach to treatment.

Peptide vaccines in breast cancer: The immunological basis for clinical response

This review discusses peptide-based vaccines in breast cancer, immune responses and clinical outcomes, which include studies on animal models and phase I, phase I/II, phase II and phase III clinical trials. Peptide-based vaccines are powerful neoadjuvant immunotherapies that can directly target proteins expressed in tumor cells, mainly tumor-associated antigens (TAAs). The most common breast cancer TAA epitopes are derived from MUC1, HER2/neu and CEA proteins. Peptides derived from TAAs could be successfully used to elicit CD8 and CD4 T cell-specific responses. Thus, choosing peptides that adapt to natural variations of human leukocyte antigen (HLA) genes is critical. The most attractive advantage is that the target response is more specific and less toxic than for other therapies and vaccines. Prominent studies on NeuVax - E75 (epitope for HER2/neu and GM-CSF) in breast cancer and DPX-0907 (HLA-A2-TAAs) expressed in breast cancer, ovarian and prostate cancer have shown the efficacy of peptide-based vaccines as neoadjuvant immunotherapy against cancer. Future peptide vaccine strategies, although a challenge to be applied in a broad range of breast cancers, point to the development of degenerate multi-epitope immunogens against multiple targets.

Peptide-Based Treatment: A Promising Cancer Therapy

Many new therapies are currently being used to treat cancer. Among these new methods, chemotherapy based on peptides has been of great interest due to the unique advantages of peptides, such as a low molecular weight, the ability to specifically target tumor cells, and low toxicity in normal tissues. In treating cancer, peptide-based chemotherapy can be mainly divided into three types, peptide-alone therapy, peptide vaccines, and peptide-conjugated nanomaterials. Peptide-alone therapy may specifically enhance the immune system's response to kill tumor cells. Peptide-based vaccines have been used in advanced cancers to improve patients' overall survival. Additionally, the combination of peptides with nanomaterials expands the therapeutic ability of peptides to treat cancer by enhancing drug delivery and sensitivity. In this review, we mainly focus on the new advances in the application of peptides in treating cancer in recent years, including diagnosis, treatment, and prognosis.

Trial Watch: Peptide-based anticancer vaccines

Malignant cells express antigens that can be harnessed to elicit anticancer immune responses. One approach to achieve such goal consists in the administration of tumor-associated antigens (TAAs) or peptides thereof as recombinant proteins in the presence of adequate adjuvants. Throughout the past decade, peptide vaccines have been shown to mediate antineoplastic effects in various murine tumor models, especially when administered in the context of potent immunostimulatory regimens. In spite of multiple limitations, first of all the fact that anticancer vaccines are often employed as therapeutic (rather than prophylactic) agents, this immunotherapeutic paradigm has been intensively investigated in clinical scenarios, with promising results. Currently, both experimentalists and clinicians are focusing their efforts on the identification of so-called tumor rejection antigens, i.e., TAAs that can elicit an immune response leading to disease eradication, as well as to combinatorial immunostimulatory interventions with superior adjuvant activity in patients. Here, we summarize the latest advances in the development of peptide vaccines for cancer therapy.