The therapeutic effect of anti-HER2/neu antibody depends on both innate and adaptive immunity

The tumor immune microenvironment remodeling and response to HER2-targeted therapy in HER2-positive advanced gastric cancer

Combination therapy with anti-HER2 agents and immunotherapy has demonstrated significant clinical benefits in gastric cancer (GC), but the underlying mechanism remains unclear. In this study, we used multiplex immunohistochemistry to assess the changes of the tumor microenvironment in 47 advanced GC patients receiving anti-HER2 therapy. Additionally, we performed single-cell transcriptional sequencing to investigate potential cell-to-cell communication and molecular mechanisms in four HER2-positive GC baseline samples. We observed that post-treated the infiltration of NK cells, CD8+ T cells, and B lymphocytes were significantly higher in patients who benefited from anti-HER2 treatment than baseline. Further spatial distribution analysis demonstrated that the interaction scores between NK cells and CD8+ T cells, B lymphocytes and M2 macrophages, B lymphocytes and Tregs were also significantly higher in benefited patients. Cell-cell communication analysis from scRNA sequencing showed that NK cells utilized CCL3/CCL4-CCR5 to recruit CD8+ T cell infiltration. B lymphocytes employed CD74-APP/COPA/MIF to interact with M2 macrophages, and utilized TNF-FAS/ICOS/TNFRSR1B to interact with Tregs. These cell-cell interactions contribute to inhibit the immune resistance of M2 macrophages and Tregs. Our research provides potential guidance for the use of anti-HER2 therapy in combination with immune therapy.

HER-2 directed therapies across gastrointestinal tract cancers - A new frontier

Gastrointestinal (GI) cancers are common and in the metastatic setting they have a poor prognosis. The current mainstay of treatment of GI cancers is chemotherapy; however, the biomarker-directed treatment landscape is evolving. HER-2 is overexpressed in a portion of GI cancers and is an emerging target for therapy, with recent FDA tumor agnostic approval for trastuzumab deruxtecan. Testing for HER-2 expression is not standardized across GI cancers, methodology requires further optimization and standardization as HER-2 targeted therapy emerges into the treatment landscape. There is established rationale for use of HER-2 targeted therapy in first line treatment of metastatic gastric cancer, and emerging evidence with variable benefit in bile duct, pancreatic and colorectal cancers.

Tumor cells impair immunological synapse formation via central nervous system-enriched metabolite

Tumors employ various strategies to evade immune surveillance. Central nervous system (CNS) has multiple features to restrain immune response. Whether tumors and CNS share similar programs of immunosuppression is elusive. Here, we analyze multi-omics data of tumors from HER2+ breast cancer patients receiving trastuzumab and anti-PD-L1 antibody and find that CNS-enriched N-acetyltransferase 8-like (NAT8L) and its metabolite N-acetylaspartate (NAA) are overexpressed in resistant tumors. In CNS, NAA is released during brain inflammation. NAT8L attenuates brain inflammation and impairs anti-tumor immunity by inhibiting cytotoxicity of natural killer (NK) cells and CD8+ T cells via NAA. NAA disrupts the formation of immunological synapse by promoting PCAF-induced acetylation of lamin A-K542, which inhibits the integration between lamin A and SUN2 and impairs polarization of lytic granules. We uncover that tumor cells mimic the anti-inflammatory mechanism of CNS to evade anti-tumor immunity and NAT8L is a potential target to enhance efficacy of anti-cancer agents.

Immunomodulation profile of the biosimilar trastuzumab MYL-1401O in a bioequivalence phase I study

The initial Phase-I single centre, single dose, randomized, double-blind, cross-over study was planned to assess the pharmacokinetic and pharmacodynamic bioequivalence of the trastuzumab biosimilar (MYL-1401O) compared to the reference Herceptin®. Their respective immunomodulation profile presented in this paper involved healthy males receiving a single infusion of both monoclonals, separated by a washout period. Sixty parameters were assessed in total, including serum cytokines, peripheral mononuclear cell (PBMC) subsets, cell activation and response to recall antigens and mitogen, pre- and post- infusion, as well as a cytokine release assay (CRA) at baseline. Trastuzumab infusion induced a transient and weak peak of serum IL-6 at 6 h, and a modulation of mononuclear cell subset profile and activation level, notably CD16 + cells. Except for CD8 + T cells, there were no significant differences between Herceptin® and MYL-1401O. In CRA, PBMC stimulated with MYL-1401O or Herceptin® similarly secreted IL-6, TNF-α, IL-1β, GM-CSF, IFN-γ, and IL-10, but no or low level of IL-2. Interestingly, some observed adverse events correlated with IL-2 and IFN-γ in CRA. MYL-1401O exhibited a very similar immunomodulation profile to Herceptin®, strongly supporting its bioequivalence. This approach may thus be included in a proof-of-concept study. CRA may be used as a predictive assay for the evaluation of clinical monoclonals.

The multiple faces of cGAS-STING in antitumor immunity: prospects and challenges

As a key sensor of double-stranded DNA (dsDNA), cyclic GMP-AMP synthase (cGAS) detects cytosolic dsDNA and initiates the synthesis of 2'3' cyclic GMP-AMP (cGAMP) that activates the stimulator of interferon genes (STING). This finally promotes the production of type I interferons (IFN-I) that is crucial for bridging innate and adaptive immunity. Recent evidence show that several antitumor therapies, including radiotherapy (RT), chemotherapy, targeted therapies and immunotherapies, activate the cGAS-STING pathway to provoke the antitumor immunity. In the last decade, the development of STING agonists has been a major focus in both basic research and the pharmaceutical industry. However, up to now, none of STING agonists have been approved for clinical use. Considering the broad expression of STING in whole body and the direct lethal effect of STING agonists on immune cells in the draining lymph node (dLN), research on the optimal way to activate STING in tumor microenvironment (TME) appears to be a promising direction. Moreover, besides enhancing IFN-I signaling, the cGAS-STING pathway also plays roles in senescence, autophagy, apoptosis, mitotic arrest, and DNA repair, contributing to tumor development and metastasis. In this review, we summarize the recent advances on cGAS-STING pathway's response to antitumor therapies and the strategies involving this pathway for tumor treatment.

Significant effect of posterior line treatment of HER2 positive advanced gastric cancer: A case report

At present, there are few options for third line and above treatment of advanced gastric cancer and the single drug effect is poor. HER2 positive gastric cancer is an important subtype of gastric cancer and has certain immune characteristics. The combination of HER2 inhibitor and PD-1 inhibitor has a synergistic effect, and anti-tumor drugs targeting HER2 can play an anti-angiogenesis role by downregulating VEGF. We report a patient with HER2-positive gastric cancer who developed post-operative tumor recurrence and metastasis after adjuvant chemotherapy and radiotherapy. Trastuzumab combined with albumin paclitaxel was used as second-line treatment with progression-free survival for 9 months. In third line treatment, we retained trastuzumab and combined it with camrelizumab and apatinib. During the treatment period, although the patient stopped taking the drugs due to the side effects of camrelizumab and apatinib, he achieved a PFS of 10.4 months. Considering the good effect of the third line treatment, we added another PD-1 inhibitor and continued to combine trastuzumab treatment. We found that the patient still benefited from the treatment and continued to survive for another 4 months. At present, the patient is treated with DisitamabVedotin (HER2-ADC) combined with PD-1 inhibitor, and no overall survival outcome has been observed.

In era of immunotherapy: the value of trastuzumab beyond progression in patients with trastuzumab-resistant HER2-positive advanced or metastatic gastric cancer

Background

For patients with human epidermal growth factor receptor-2 (HER2)-positive advanced or metastatic gastric cancer who have progressed on first-line trastuzumab therapy, the clinical value of the continuous use of trastuzumab beyond progression (TBP) is controversial.

Objectives

The present study was conducted to evaluate the efficacy and explore new treatment strategies of TBP for patients with trastuzumab-resistant HER2-positive advanced or metastatic gastric cancer in the era of cancer immunotherapy.

Design

Retrospective analysis.

Methods

Patients with HER2-positive advanced or metastatic gastric cancer who have failed first-line treatment based on trastuzumab-targeted therapy from June 2019 to December 2020 were retrospectively analyzed. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), objective response rate (ORR), disease control rate (DCR), and safety. Survival curves of patients were estimated by the Kaplan-Meier method and compared using the log-rank test.

Results

In all, 30 patients received TBP with chemotherapy, immunotherapy, or anti-angiogenic therapy, and the other 26 patients received treatment of physician's choice without trastuzumab. The median PFS in the TBP and non-TBP population was 6.0 [95% confidence interval (CI) = 3.8-8.2] and 3.5 (95% CI = 2.2-4.8) months, respectively (p = 0.038), and the median OS was 12.3 (95% CI = 10.4-14.2) and 9.0 (95% CI = 6.6-11.4) months (p = 0.008). The patients who received TBP treatment had more favorable PFS and OS than the non-TBP population. In the TBP group, patients who received trastuzumab plus chemotherapy and immunotherapy had higher ORR (40.0% versus 16.7%), DCR (90.0% versus 50.0%), and showed a significant improvement in PFS (7.0 versus 1.9 m) compared to TBP with chemotherapy alone. Subgroup analysis suggested that patients with male, HER2 positive with immunohistochemistry score 3+ and PFS of first-line treatment less than 6 months had a greater benefit from TBP. The incidence of Grade 3-4 adverse events in the TBP and non-TBP groups was 43.3% and 38.5%.

Conclusion

The continuous use of TBP improves PFS and OS in patients with trastuzumab-resistant HER2-positive advanced or metastatic gastric cancer with well-tolerated toxicity. In the era of immunotherapy, TBP combined with chemotherapy and immunotherapy may further enhance the clinical benefit and provide a new treatment strategy.

Trial registration

This study is a retrospective study, which does not require clinical registration.

In vivo Auto-tuning of Antibody-Drug Conjugate Delivery for Effective Immunotherapy using High-Avidity, Low-Affinity Antibodies

Antibody-drug conjugates (ADCs) have experienced a surge in clinical approvals in the past five years. Despite this success, a major limitation to ADC efficacy in solid tumors is poor tumor penetration, which leaves many cancer cells untargeted. Increasing antibody doses or co-administering ADC with an unconjugated antibody can improve tumor penetration and increase efficacy when target receptor expression is high. However, it can also reduce efficacy in low-expression tumors where ADC delivery is limited by cellular uptake. This creates an intrinsic problem because many patients express different levels of target between tumors and even within the same tumor. Here, we generated High-Avidity, Low-Affinity (HALA) antibodies that can automatically tune the cellular ADC delivery to match the local expression level. Using HER2 ADCs as a model, HALA antibodies were identified with the desired HER2 expression-dependent competitive binding with ADCs in vitro. Multi-scale distribution of trastuzumab emtansine and trastuzumab deruxtecan co-administered with the HALA antibody were analyzed in vivo, revealing that the HALA antibody increased ADC tumor penetration in high-expression systems with minimal reduction in ADC uptake in low-expression tumors. This translated to greater ADC efficacy in immunodeficient mouse models across a range of HER2 expression levels. Furthermore, Fc-enhanced HALA antibodies showed improved Fc-effector function at both high and low expression levels and elicited a strong response in an immunocompetent mouse model. These results demonstrate that HALA antibodies can expand treatment ranges beyond high expression targets and leverage strong immune responses.

Human Tumor-Associated Macrophages and Neutrophils Regulate Antitumor Antibody Efficacy through Lethal and Sublethal Trogocytosis

The clinical benefits of tumor-targeting antibodies (tAb) are modest in solid human tumors. The efficacy of many tAbs is dependent on Fc receptor (FcR)-expressing leukocytes that bind Fc fragments of tAb. Tumor-associated macrophages (TAM) and neutrophils (TAN) represent the majority of FcR+ effectors in solid tumors. A better understanding of the mechanisms by which TAMs and TANs regulate tAb response could help improve the efficacy of cancer treatments. Here, we found that myeloid effectors interacting with tAb-opsonized lung cancer cells used antibody-dependent trogocytosis (ADT) but not antibody-dependent phagocytosis. During this process, myeloid cells "nibbled off" tumor cell fragments containing tAb/targeted antigen (tAg) complexes. ADT was only tumoricidal when the tumor cells expressed high levels of tAg and the effectors were present at high effector-to-tumor ratios. If either of these conditions were not met, which is typical for solid tumors, ADT was sublethal. Sublethal ADT, mainly mediated by CD32hiCD64hi TAM, led to two outcomes: (i) removal of surface tAg/tAb complexes from the tumor that facilitated tumor cell escape from the tumoricidal effects of tAb; and (ii) acquisition of bystander tAgs by TAM with subsequent cross-presentation and stimulation of tumor-specific T-cell responses. CD89hiCD32loCD64lo peripheral blood neutrophils (PBN) and TAN stimulated tumor cell growth in the presence of the IgG1 anti-EGFR Ab cetuximab; however, IgA anti-EGFR Abs triggered the tumoricidal activity of PBN and negated the stimulatory effect of TAN. Overall, this study provides insights into the mechanisms by which myeloid effectors mediate tumor cell killing or resistance during tAb therapy.

SIGNIFICANCE

The elucidation of the conditions and mechanisms by which human FcR+ myeloid effectors mediate cancer cell resistance and killing during antibody treatment could help develop improved strategies for treating solid tumors.

Genetic/Epigenetic Alteration and Tumor Immune Microenvironment in Intrahepatic Cholangiocarcinoma: Transforming the Immune Microenvironment with Molecular-Targeted Agents

Background

Intrahepatic cholangiocarcinoma (iCCA) is often diagnosed at an advanced stage, leading to limited treatment options and a poor prognosis. So far, standard systemic therapy for advanced iCCA has been a combination of gemcitabine and cisplatin. However, recent advancements in the understanding of the molecular characteristics of iCCA have opened new possibilities for molecular-targeted therapies and immunotherapy.

Summary

Reportedly, 9-36% of iCCA cases have an inflamed tumor immune microenvironment (TME) based on the immune gene expression signature, which is characterized by the presence of immune cells involved in anti-tumor immune responses. The majority of iCCA cases have a non-inflamed TME with a lack of effector T cells, rendering immune checkpoint inhibitors (ICIs) ineffective in these cases. Interestingly, alterations in the fibroblast growth factor receptor (FGFR2) gene and IDH1/2 gene mutations are often observed in the non-inflamed TME in iCCA. Several mechanisms have been reported for the role of driver mutations on the establishment of TME unique for iCCA. For example, IDH1/2 mutations, which cause an increase in DNA methylation, are associated with the downregulation and hypermethylation of antigen processing and presentation machinery, which may contribute to the establishment of a non-inflamed TME. Therefore, inhibitors targeting IDH1/2 may restore the DNA methylation and expression status of molecules involved in antigen presentation, potentially improving the efficacy of ICIs. FGFR inhibitors may also have the potential to modulate immunosuppressive TME by inhibitingthe suppressor of cytokine signaling 1 and activating the interferon-γ signaling as a consequence of inhibition of the FGFR signal. From this perspective, understanding the molecular characteristics of iCCA, including the TME and driver mutations, is essential for the effective application of ICIs and molecular-targeted therapies.

Key Messages

Combination approaches that target both the tumor and immune system hold promise for improving the outcomes of patients with iCCA. Further research and clinical trials are needed to validate these approaches and optimize the treatment strategies for iCCA.

Novel peptide-based oncolytic vaccine for enhancement of adaptive antitumor immune response via co-engagement of innate Fcγ and Fcα receptors

BACKGROUND

Cancer immunotherapy relies on using the immune system to recognize and eradicate cancer cells. Adaptive immunity, which consists of mainly antigen-specific cytotoxic T cells, plays a pivotal role in controlling cancer progression. However, innate immunity is a necessary component of the cancer immune response to support an immunomodulatory state, enabling T-cell immunosurveillance.

METHODS

Here, we elucidated and exploited innate immune cells to sustain the generation of antigen-specific T cells on the use of our cancer vaccine platform. We explored a previously developed oncolytic adenovirus (AdCab) encoding for a PD-L1 (Programmed-Death Ligand 1) checkpoint inhibitor, which consists of a PD-1 (Programmed Cell Death Protein 1) ectodomain fused to an IgG/A cross-hybrid Fc. We coated AdCab with major histocompatibility complex (MHC-I)-restricted tumor peptides, generating a vaccine platform (named PeptiCab); the latter takes advantage of viral immunogenicity, peptide cancer specificity to prime T-cell responses, and antibody-mediated effector functions.

RESULTS

As proof of concept, PeptiCab was used in murine models of melanoma and colon cancer, resulting in tumor growth control and generation of systemic T-cell-mediated antitumor responses. In specific, PeptiCab was able to generate antitumor T effector memory cells able to secrete various inflammatory cytokines. Moreover, PeptiCab was able to polarize neutrophils to attain an antigen-presenting phenotype by upregulating MHC-II, CD80 and CD86 resulting in an enhanced T-cell expansion.

CONCLUSION

Our data suggest that exploiting innate immunity activates T-cell antitumor responses, enhancing the efficiency of a vaccine platform based on oncolytic adenovirus coated with MHC-I-restricted tumor peptides.

Worldwide research trends on tumor burden and immunotherapy: a bibliometric analysis

Various immunotherapy has been greatly applied to comprehensive treatment of malignant cancer under different degrees of tumor burden. Scientific researchers have gained considerable progress in the relationship between immunotherapy and tumor burden in recent years. This review aimed to explore the prospect and developing trends in the field of tumor burden and immunotherapy from a bibliometric perspective. Articles about tumor burden and immunotherapy were collected from the Web of Science Core Collection (WoSCC) (retrieved on 3 January 2023). The R package 'Bibliometrix' analyzed the primary bibliometric features and created a three-filed plot to display the relationship between institutions, countries, and keywords. VOSviewer was used for co-authorship analysis, co-occurrence analysis, and their visualization. And CiteSpace calculated the citation burst references and keywords. A total of 1030 publications were retrieved from 35 years of scientific researches. The United States (US) and China published the most articles. The most productive journals were Cancer Immunology Immunotherapy and Journal for ImmunoTherapy of Cancer . The top one institution of the highest output was University of Texas MD Anderson Cancer Center. The hot keywords of strong citation burst strength in recent years were 'nivolumab', 'tumor microenvironment', and 'immune checkpoint inhibitor'. The most popular tumor type is melanoma. This bibliometric analysis mapped a basic knowledge structure. The field of tumor burden and immunotherapy is entering a rapid growing stage and keeping it value for future research.

Prognostic impact of HER2 biomarker levels in trastuzumab-treated early HER2-positive breast cancer

BACKGROUND

Overexpression of human epidermal growth factor receptor 2 (HER2) caused by HER2 gene amplification is a driver in breast cancer tumorigenesis. We aimed to investigate the prognostic significance of manual scoring and digital image analysis (DIA) algorithm assessment of HER2 copy numbers and HER2/CEP17 ratios, along with ERBB2 mRNA levels among early-stage HER2-positive breast cancer patients treated with trastuzumab.

METHODS

This retrospective study comprised 371 early HER2-positive breast cancer patients treated with adjuvant trastuzumab, with HER2 re-testing performed on whole tumor sections. Digitized tumor tissue slides were manually scored and assessed with uPath HER2 Dual ISH image analysis, breast algorithm. Targeted ERBB2 mRNA levels were assessed by the Xpert® Breast Cancer STRAT4 Assay. HER2 copy number and HER2/CEP17 ratio from in situ hybridization assessment, along with ERBB2 mRNA levels, were explored in relation to recurrence-free survival (RFS).

RESULTS

The analysis showed that patients with tumors with the highest and lowest manually counted HER2 copy number levels had worse RFS than those with intermediate levels (HR = 2.7, CI 1.4-5.3, p = 0.003 and HR = 2.1, CI 1.1-3.9, p = 0.03, respectively). A similar trend was observed for HER2/CEP17 ratio, and the DIA algorithm confirmed the results. Moreover, patients with tumors with the highest and the lowest values of ERBB2 mRNA had a significantly worse prognosis (HR = 2.7, CI 1.4-5.1, p = 0.003 and HR = 2.8, CI 1.4-5.5, p = 0.004, respectively) compared to those with intermediate levels.

CONCLUSIONS

Our findings suggest that the association between any of the three HER2 biomarkers and RFS was nonlinear. Patients with tumors with the highest levels of HER2 gene amplification or ERBB2 mRNA were associated with a worse prognosis than those with intermediate levels, which is of importance to investigate in future clinical trials studying HER2-targeted therapy.

Reviewing the significance of dendritic cell vaccines in interrupting breast cancer development

Breast cancer is a heterogeneous disease and is the most prevalent cancer in women. According to the U.S breast cancer statistics, about 1 in every 8 women develop an invasive form of breast cancer during their lifetime. Immunotherapy has been a significant advancement in the treatment of cancer with multiple studies reporting favourable patient outcomes by modulating the immune response to cancer cells. Here, we review the significance of dendritic cell vaccines in treating breast cancer patients. We discuss the involvement of dendritic cells and oncodrivers in breast tumorigenesis, highlighting the rationale for targeting oncodrivers and neoantigens using dendritic cell vaccine therapy. We review different dendritic cell subsets and maturation states previously used to develop vaccines and suggest the use of DC vaccines for breast cancer prevention. Further, we highlight that the intratumoral delivery of type 1 dendritic cell vaccines in breast cancer patients activates tumor antigen-specific CD4+ T helper cell type 1 (Th1) cells, promoting an anti-tumorigenic immune response while concurrently blocking pro-tumorigenic responses. In summary, this review provides an overview of the current state of dendritic cell vaccines in breast cancer highlighting the challenges and considerations necessary for an efficient dendritic cell vaccine design in interrupting breast cancer development.

Molecular Targeting of the Human Epidermal Growth Factor Receptor-2 (HER2) Genes across Various Cancers

Human epidermal growth factor receptor 2 (HER2) belongs to the ErbB family, a group of four transmembrane glycoproteins with tyrosine kinase activity, all structurally related to epidermal growth factor receptor (EGFR). These tyrosine kinases are involved in the transmission of cellular signals controlling normal cell growth and differentiation. If this transmission goes awry, it can lead to dysregulated growth of the cell. HER2 specifically can be implicated in the pathogenesis of at least eight malignancies. HER2 positivity quickly became a well-characterized indicator of aggressiveness and poor prognosis, with high rates of disease progression and mortality. After realizing the implication of HER2, it first became investigated as a target for treatment in breast cancer, and later expanded to areas of research in other cancer types. To this day, the most therapeutic advancements of anti-HER2 therapy have been in breast cancer; however, there have been strong advancements made in the incorporation of anti-HER2 therapy in other cancer types as well. This comprehensive review dissects HER2 to its core, incorporating the most up to date information. The topics touched upon are discussed in detail and up to 200 published sources from the most highly recognized journals have been integrated. The importance of knowing about HER2 is exemplified by the groundbreaking advancements that have been made, and the change in treatment plans it has brought to the oncological world in the last twenty years. Since its groundbreaking discovery there have been significant breakthroughs in knowledge regarding the actual receptor, the receptors biology, its mechanism of action, and advancements in tests to detect HER2 and significant strides on how to best incorporate targeted treatment. Due to the success of this field thus far, the review concludes by discussing the future of novel anti-HER2 therapy currently in development that everyone should be aware of.

Novel HER-2 Targeted Therapies in Breast Cancer

Human epidermal growth factor 2 (HER-2)-positive breast cancer represents 15-20% of all breast cancer subtypes and has an aggressive biological behavior with worse prognosis. The development of HER-2-targeted therapies has changed the disease's course, having a direct impact on survival rates and quality of life. Drug development of HER-2-targeting therapies is a prolific field, with numerous new therapeutic strategies showing survival benefits and gaining regulatory approval in recent years. Furthermore, the acknowledgement of the survival impact of HER-2-directed therapies on HER-2-low breast cancer has contributed even more to advances in the field. The present review aims to summarize the newly approved therapeutic strategies for HER-2-positive breast cancer and review the new and exploratory HER-2-targeted therapies currently under development.

Systemic Therapies for HER2-Positive Advanced Breast Cancer

Despite recent advances, HER2-positive advanced breast cancer (ABC) remains a largely incurable disease, with resistance to conventional anti-HER2 drugs ultimately unavoidable for all but a small minority of patients who achieve an enduring remission and possibly cure. Over the past two decades, significant advances in our understanding of the underlying molecular mechanisms of HER2-driven oncogenesis have translated into pharmaceutical advances, with the developing of increasingly sophisticated therapies directed against HER2. These include novel, more potent selective HER2 tyrosine kinase inhibitors (TKIs); new anti-HER2 antibody-drug conjugates; and dual epitope targeting antibodies, with more advanced pharmacological properties and higher affinity. With the introduction of adjuvant T-DM1 for incomplete responders to neoadjuvant therapy, fewer patients are relapsing, but for those who do relapse, disease that may be resistant to standard first- and second-line therapies requires new approaches. Furthermore, the risk of CNS relapse has not been abrogated by current (neo)adjuvant strategies; therefore, current research efforts are being directed towards this challenging site of metastatic disease. In this article, we review the currently available clinical data informing the effective management of HER2-positive breast cancer beyond standard first-line therapy with pertuzumab, trastuzumab, and taxanes, and the management of relapse in patients who have already been exposed to both these agents and T-DM1 for early breast cancer (EBC). We additionally discuss novel anti-HER2 targeted agents and combinations in clinical trials, which may be integrated into standard treatment paradigms in the future.

Anti-cathepsin D immunotherapy triggers both innate and adaptive anti-tumour immunity in breast cancer

BACKGROUND AND PURPOSE

Triple-negative breast cancer (TNBC) has poorer outcomes than other breast cancers (BC), including HER2+ BC. Cathepsin D (CathD) is a poor prognosis marker overproduced by BC cells, hypersecreted in the tumour microenvironment with tumour-promoting activity. Here, we characterized the immunomodulatory activity of the anti-CathD antibody F1 and its improved Fab-aglycosylated version (F1M1) in immunocompetent mouse models of TNBC (C57BL/6 mice harbouring E0771 cell grafts) and HER2-amplified BC (BALB/c mice harbouring TUBO cell grafts).

EXPERIMENTAL APPROACH

CathD expression was evaluated by western blotting and immunofluorescence, and antibody binding to CathD by ELISA. Antibody anti-tumour efficacy was investigated in mouse models. Immune cell recruitment and activation were assessed by immunohistochemistry, immunophenotyping, and RT-qPCR.

KEY RESULTS

F1 and F1M1 antibodies remodelled the tumour immune landscape. Both antibodies promoted innate antitumour immunity by preventing the recruitment of immunosuppressive M2-polarized tumour-associated macrophages (TAMs) and by activating natural killer cells in the tumour microenvironment of both models. This translated into a reduction of T-cell exhaustion markers in the tumour microenvironment that could be locally supported by enhanced activation of anti-tumour antigen-presenting cell (M1-polarized TAMs and cDC1 cells) functions. Both antibodies inhibited tumour growth in the highly-immunogenic E0771 model, but only marginally in the immune-excluded TUBO model, indicating that anti-CathD immunotherapy is more relevant for BC with a high immune cell infiltrate, as often observed in TNBC.

CONCLUSION AND IMPLICATION

Anti-CathD antibody-based therapy triggers the anti-tumour innate and adaptive immunity in preclinical models of BC and is a promising immunotherapy for immunogenic TNBC.

Randomized, open-label, phase II, biomarker study of immune-mediated mechanism of action of neoadjuvant subcutaneous trastuzumab in patients with locally advanced, inflammatory, or early HER2-positive breast cancer-Immun-HER trial (GOIRC-01-2016)

BACKGROUND

It is possible to induce immunomodulation in HER2-positive breast cancer (BC) by modifying the route of administration of trastuzumab.

METHODS

In this multicenter randomized phase II trial, all enrolled patients (pts) with T2-T4d HER2-positive BC received 3 cycles of neoadjuvant treatment (NAT) with fluorouracil, epirubicin and cyclophosphamide every 3 weeks (q21), followed by docetaxel/pertuzumab plus intravenous trastuzumab (arm A) or, docetaxel/pertuzumab plus subcutaneous (SC) trastuzumab (arm B) q21x4 cycles. After surgical operation, each pt was treated with trastuzumab q21x14 cycles using the same SC or intravenous formulation of NAT. Primary endpoint was the proportion of subjects with high stromal tumor-infiltrating lymphocytes (sTILs) in postneoadjuvant residual disease (RD).

RESULTS

Sixty-three pts (31 (arm A) and 32 (arm B)) were enrolled. Pathological complete response was obtained by 20/31 pts (64.5%; 95% CI 45.4% to 80.1%) in arm A and 19/32 pts (59.4%; 95% CI 40.1% to 76.3%) in arm B. High sTILs were observed in 27% and 46% of postneoadjuvant residual tumors in arms A and B, respectively. CD8+ T cells increased significantly in RDs of both arms (p=0.014 and 0.002 for arm A and B, respectively), whereas a significant decline in the level of CD4+ FoxP3+ regulatory T cells was observed only in arm B (p=0.016). A significant upregulation of PD-1 on sTILs was found in RD of pts enrolled in arm B (p=0.012), while programmed death-ligand 1 (PD-L1) was significantly overexpressed in residual tumors of arm A (p=0.02). A strong negative correlation was reported in arm B between expression of PD-L1 on pretreatment sTILs and CD3 expression on sTILs in RD (τ: -0.73). Grade≥3 AE incidence rates were similar between the two arms.

CONCLUSIONS

SC trastuzumab induced relevant sTILs enrichment, with favorable variations of immune parameters in HER2-positive BC pts with RD after NAT. Novel immunotherapy strategies should be tested to achieve SC-specific, antitumor immune response.

TRIAL REGISTRATION NUMBER

NCT03144947, and EudraCT number: 2016-000435-41.

How B cells drive T-cell responses: A key role for cross-presentation of antibody-targeted antigens

In this review we discuss an underexposed mechanism in the adaptive immune system where B cell and T cell immunity collaborate. The main function of B cell immunity is the generation of antibodies which are well known for their high affinity and antigen-specificity. Antibodies can bind antigens in soluble form making so-called immune complexes (ICs) or can opsonize antigen-exposing cells or particles for degradation. This leads to well-known effector mechanisms complement activation, antibody-dependent cytotoxicity and phagocytosis. What is less realized is that antibodies can play an important role in the targeting of antigen to dendritic cells (DCs) and thereby can drive T cell immunity. Here we summarize the studies that described this highly efficient process of antibody-mediated antigen uptake in DCs in vitro and in vivo. Only very low doses of antigen can be captured by circulating antibodies and subsequently trapped by DCs in vivo. We studied the handling of these ICs by DCs in subcellular detail. Upon immune complex engulfment DCs can sustain MHC class I and II antigen presentation for many days. Cell biological analysis showed that this function is causally related to intracellular antigen-storage compartments which are functional endolysosomal organelles present in DCs. We speculate that this function is immunologically very important as DCs require time to migrate from the site of infection to the draining lymph nodes to activate T cells. The implications of these findings and the consequences for the immune system, immunotherapy with tumor-specific antibodies and novel vaccination strategies are discussed.

RC48-ADC treatment for patients with HER2-expressing locally advanced or metastatic solid tumors: a real-world study

BACKGROUND

RC48-antibody-drug conjugates (ADC) link humanized anti-HER2 immunoglobulin with monomethyl auristatin E (MMAE). Clinical trials suggest promising antitumor activity in HER2-expressing solid tumors. This study probes RC48-ADC's efficacy and safety in patients with HER2-expressing advanced or metastatic solid tumors.

METHOD

Data was collected from 23 advanced cancer patients treated with RC48-ADC at our oncology center between July 2021 and December 2022. These patients exhibited at least 1 + expression of HER2 immunohistochemistry, had previously experienced at least one failed systemic chemotherapy, and were treated with RC48-ADC until the occurrence of intolerable adverse reactions or disease progression. The primary endpoint was the disease control rate (DCR), and secondary endpoints included progression-free survival (PFS), objective response rate (ORR), and safety.

RESULTS

23 of 25 screened patients received RC48 treatment. The ORR was 43.5% (95% CI, 23.2-63.7%) with a median PFS of 6.0 months (95% CI, 4.8-7.4). In the low-to-medium HER2 expression subgroup, ORR was 37.5%, median PFS 5.75 months. In the high HER2 expression subgroup, ORR was 57.1%, median PFS 7 months. For the cohort combining RC48 with PD-1 inhibitors, ORR was 53.8%, median PFS 8 months. In the concurrent local radiation therapy subgroup, ORR was 40.0%, median PFS 6.0 months. Treatment-related adverse events (TRAEs) were anemia (60.8%), leukopenia (56.2%), raised transaminases (52.17%), and neutropenia (43.5%). Five patients (21.7%) experienced Grade 3 symptoms, including anemia (21.7%) and neutropenia (14.0%). No Grade 4 adverse reactions or deaths were reported.

CONCLUSION

RC48-ADC shows promising efficacy and manageable safety in HER2-expressing advanced or metastatic solid tumor patients.

Cuproptosis-related LINC02454 as a biomarker for laryngeal squamous cell carcinoma based on a novel risk model and in vitro and in vivo analyses

PURPOSE

Laryngeal squamous cell carcinomas (LSCCs) are aggressive tumors with the second-highest morbidity rate in patients with head and neck squamous cell carcinoma. Cuproptosis is a type of programmed cell death that impacts tumor malignancy and progression. The purpose of this study was to investigate the relationship between cuproptosis-related long non-coding RNAs (crlncRNAs) and the tumor immune microenvironment and chemotherapeutic drug sensitivity in LSCC, and crlncRNA impact on LSCC malignancy.

MATERIALS AND METHODS

Clinical and RNA-sequencing data from patients with LSCC were retrieved from the Cancer Genome Atlas. Differentially expressed prognosis-related crlncRNAs were identified based on univariate Cox regression analysis, a crlncRNA signature for LSCC was developed and validated using LASSO Cox regression. Finally, the effect of LINC02454, the core signature crlncRNA, on LSCC malignancy progression was evaluated in vitro and in vivo.

RESULTS

We identified a four-crlncRNA signature (LINC02454, AC026310.1, AC090517.2, and AC000123.1), according to which we divided the patients into high- and low-risk groups. The crlncRNA signature risk score was an independent prognostic indicator for overall and progression-free survival, and displayed high predictive accuracy. Patients with a higher abundance of infiltrating dendritic cells, M0 macrophages, and neutrophils had worse prognoses and those in the high-risk group were highly sensitive to multiple chemotherapeutic drugs. Knockdown of LINC02454 caused tumor suppression, via cuproptosis induction.

CONCLUSIONS

A novel signature of four crlncRNAs was found to be highly accurate as a risk prediction model for patients with LSCC and to have potential for improving the diagnosis, prognosis, and treatment of LSCC.

HER-2 Expression in Colorectal Cancer and Its Correlation with Immune Cell Infiltration

BACKGROUND

This study aimed to investigate the effect of increased HER-2 expression on tumor-infiltrating lymphocytes (TILs) and determine its impact on the prognosis of colorectal cancer (CRC) patients; Methods: HER-2, CD4, CD8, CD19, LY6G, CD56, CD68, CD11b, and EpCam expression in CRC tissues and adjacent paracancerous tissues were assessed using multiplex fluorescence immunohistochemical staining. The correlation between HER-2 expression and the number of TILs in CRC tissues was analyzed. Kaplan-Meier and Cox proportional hazards models were used to analyze survival outcomes; Results: The expression of HER-2 in tumor tissues was higher than that in paracancerous tissues (1.31 ± 0.45 vs. 0.86 ± 0.20, p < 0.05). Additionally, there was an increase in the numbers of CD4+, CD8+, CD19+, and CD68+ cells in CRC tissues (14.11 ± 1.10 vs. 3.40 ± 0.18, p < 0.005; 0.16 ± 0.12 vs. 0.04 ± 0.04, p < 0.005; 0.71 ± 0.46 vs. 0.25 ± 0.13, p < 0.0005; 0.27 ± 0.24 vs. 0.03 ± 0.11, p < 0.05). An increase in HER-2 expression was positively correlated with an increase in CD4, CD8, and CD19 (p < 0.0001). In HER-2-positive CRC tissues, CD68 expression was increased (0.80 ± 0.55 vs. 0.25 ± 0.22, p < 0.05). In HER-2-upregulated CRC tissues, CD4, CD8, CD19, CD68, CD11b, Ly6G, and CD56 expressions were elevated (0.70 ± 0.37 vs. 0.32 ± 0.17, p = 0.03; 0.22 ± 0.13 vs. 0.09 ± 0.06, p = 0.03; 0.31 ± 0.19 vs. 0.12 ± 0.08, p = 0.02; 1.05 ± 0.62 vs. 0.43 ± 0.21, p < 0.01; 1.34 ± 0.81 vs. 0.53 ± 0.23, p < 0.01; 0.50 ± 0.31 vs. 0.19 ± 0.10, p < 0.01; 1.26 ± 0.74 vs. 0.52 ± 0.24, p < 0.01). Furthermore, increased HER-2 expression was an independent risk factor for recurrence-free survival (RFS) in patients (p < 0.01, HR = 3.421); Conclusions: The increased expression of HER-2 and its relationship with immune cells will provide new insights for immunotherapy in CRC patients.

A novel nanobody-based HER2-targeting antibody exhibits potent synergistic antitumor efficacy in trastuzumab-resistant cancer cells

Human epithelial growth factor receptor-2 (HER2) plays an oncogenic role in numerous tumors, including breast, gastric, and various other solid tumors. While anti-HER2 therapies are approved for the treatment of HER2-positive tumors, a necessity persists for creating novel HER2-targeted agents to resolve therapeutic resistance. Utilizing a synthetic nanobody library and affinity maturation, our study identified four anti-HER2 nanobodies that exhibited high affinity and specificity. These nanobodies recognized three distinct epitopes of HER2-ECD. Additionally, we constructed VHH-Fc and discovered that they facilitated superior internalization and showed moderate growth inhibition. Compared to the combination of trastuzumab and pertuzumab, the VHH-Fc combos or their combination with trastuzumab demonstrated greater or comparable antitumor activity in both ligand-independent and ligand-driven tumors. Most remarkably, A9B5-Fc, which targeted domain I of HER2-ECD, displayed significantly enhanced trastuzumab-synergistic antitumor efficacy compared to pertuzumab under trastuzumab-resistant conditions. Our findings offer anti-HER2 nanobodies with high affinity and non-overlapping epitope recognition. The novel nanobody-based HER2-targeted antibody, A9B5-Fc, binding to HER2-ECD I, mediates promising receptor internalization. It possesses the potential to serve as a potent synergistic partner with trastuzumab, contributing to overcoming acquired resistance.

Current and Emerging Role of Monoclonal Antibody-Based First-Line Treatment in Advanced Gastro-Esophageal and Gastric Cancer

Gastric cancer is the fifth most common malignancy worldwide and one of the main causes of cancer-related death. While surgical treatment is the only curative option for early disease, many have inoperable or advanced disease at diagnosis. Treatment in this case would be a combination of chemotherapy and immunotherapy. Gastro-esophageal (GEJ) and gastric cancer (GC) genetic profiling with current molecular diagnostic techniques has significantly changed the therapeutic landscape in advanced cancers. The identification of key players in GEJ and GC survival and proliferation, such as human epidermal growth factor 2 (HER2), vascular endothelial growth factor (VEGF), and programmed cell death protein 1 (PD-1)/programmed cell death ligand-1 (PD-L1), has allowed for the individualization of advanced cancer treatment and significant improvement in overall survival and progression-free survival of patients. This review comprehensively examines the current and emerging role of monoclonal antibody-based first-line treatments in advanced GEJ and GC. We explore the impact of monoclonal antibodies targeting HER2, VEGF, PD-1/PD-L1, and Claudin 18.2 (CLDN18.2) on the first-line treatment landscape by talking about key clinical trials. This review emphasizes the importance of biomarker testing for optimal treatment selection and provides practical recommendations based on ASCO guidelines.

B-cells and regulatory T-cells in the microenvironment of HER2+ breast cancer are associated with decreased survival: a real-world analysis of women with HER2+ metastatic breast cancer

BACKGROUND

Despite major improvements in treatment of HER2-positive metastatic breast cancer (MBC), only few patients achieve complete remission and remain progression free for a prolonged time. The tumor immune microenvironment plays an important role in the response to treatment in HER2-positive breast cancer and could contain valuable prognostic information. Detailed information on the cancer-immune cell interactions in HER2-positive MBC is however still lacking. By characterizing the tumor immune microenvironment in patients with HER2-positive MBC, we aimed to get a better understanding why overall survival (OS) differs so widely and which alternative treatment approaches may improve outcome.

METHODS

We included all patients with HER2-positive MBC who were treated with trastuzumab-based palliative therapy in the Netherlands Cancer Institute between 2000 and 2014 and for whom pre-treatment tissue from the primary tumor or from metastases was available. Infiltrating immune cells and their spatial relationships to one another and to tumor cells were characterized by immunohistochemistry and multiplex immunofluorescence. We also evaluated immune signatures and other key pathways using next-generation RNA-sequencing data. With nine years median follow-up from initial diagnosis of MBC, we investigated the association between tumor and immune characteristics and outcome.

RESULTS

A total of 124 patients with 147 samples were included and evaluated. The different technologies showed high correlations between each other. T-cells were less prevalent in metastases compared to primary tumors, whereas B-cells and regulatory T-cells (Tregs) were comparable between primary tumors and metastases. Stromal tumor-infiltrating lymphocytes in general were not associated with OS. The infiltration of B-cells and Tregs in the primary tumor was associated with unfavorable OS. Four signatures classifying the extracellular matrix of primary tumors showed differential survival in the population as a whole.

CONCLUSIONS

In a real-world cohort of 124 patients with HER2-positive MBC, B-cells, and Tregs in primary tumors are associated with unfavorable survival. With this paper, we provide a comprehensive insight in the tumor immune microenvironment that could guide further research into development of novel immunomodulatory strategies.

Determinants of Survival with Combined HER2 and PD-1 Blockade in Metastatic Esophagogastric Cancer

PURPOSE

We report updated clinical outcomes from a phase II study of pembrolizumab, trastuzumab, and chemotherapy (PTC) in metastatic esophagogastric cancer in conjunction with outcomes from an independent Memorial Sloan Kettering (MSK) cohort.

PATIENTS AND METHODS

The significance of pretreatment 89Zr-trastuzumab PET, plasma circulating tumor DNA (ctDNA) dynamics, and tumor HER2 expression and whole exome sequencing was evaluated to identify prognostic biomarkers and mechanisms of resistance in patients treated on-protocol with PTC. Additional prognostic features were evaluated using a multivariable Cox regression model of trastuzumab-treated MSK patients (n = 226). Single-cell RNA sequencing (scRNA-seq) data from MSK and Samsung were evaluated for mechanisms of therapy resistance.

RESULTS

89Zr-trastuzumab PET, scRNA-seq, and serial ctDNA with CT imaging identified how pre-treatment intrapatient genomic heterogeneity contributes to inferior progression-free survival (PFS). We demonstrated that the presence of intensely avid lesions by 89Zr-trastuzumab PET declines in tumor-matched ctDNA by 3 weeks, and clearance of tumor-matched ctDNA by 9 weeks were minimally invasive biomarkers of durable PFS. Paired pre- and on-treatment scRNA-seq identified rapid clearance of HER2-expressing tumor clones with expansion of clones expressing a transcriptional resistance program, which was associated with MT1H, MT1E, MT2A, and MSMB expression. Among trastuzumab-treated patients at MSK, ERBB2 amplification was associated with improved PFS, while alterations in MYC and CDKN2A/B were associated with inferior PFS.

CONCLUSIONS

These findings highlight the clinical relevance of identifying baseline intrapatient heterogeneity and serial ctDNA monitoring of HER2-positive esophagogastric cancer patients to identify early evidence of treatment resistance, which could guide proactive therapy escalation or deescalation.

Targeting collagen XVIII improves the efficiency of ErbB inhibitors in breast cancer models

The tumor extracellular matrix (ECM) critically regulates cancer progression and treatment response. Expression of the basement membrane component collagen XVIII (ColXVIII) is induced in solid tumors, but its involvement in tumorigenesis has remained elusive. We show here that ColXVIII was markedly upregulated in human breast cancer (BC) and was closely associated with a poor prognosis in high-grade BCs. We discovered a role for ColXVIII as a modulator of epidermal growth factor receptor tyrosine kinase (ErbB) signaling and show that it forms a complex with ErbB1 and -2 (also known as EGFR and human epidermal growth factor receptor 2 [HER2]) and α6-integrin to promote cancer cell proliferation in a pathway involving its N-terminal portion and the MAPK/ERK1/2 and PI3K/AKT cascades. Studies using Col18a1 mouse models crossed with the mouse mammary tumor virus-polyoma virus middle T antigen (MMTV-PyMT) mammary carcinogenesis model showed that ColXVIII promoted BC growth and metastasis in a tumor cell-autonomous manner. Moreover, the number of mammary cancer stem cells was significantly reduced in the MMTV-PyMT and human cell models upon ColXVIII inhibition. Finally, ablation of ColXVIII substantially improved the efficacy of ErbB-targeting therapies in both preclinical models. In summary, ColXVIII was found to sustain the stemness properties of BC cells and tumor progression and metastasis through ErbB signaling, suggesting that targeting ColXVIII in the tumor milieu may have important therapeutic potential.

Disitamab Vedotin (RC48) combined with bevacizumab for treatment of HR-negative/HER2-positive metastatic breast cancer with liver and brain involvement: A case report

Background

The overexpression of human epidermal growth factor receptor 2 (HER2) is strongly correlated with an elevated risk of developing distant metastases, particularly brain metastases, in breast cancer (BC) cases. RC48 (also known as Disitamab vedotin), represents a promising antibody-drug conjugate (ADC), that comprises three well-defined components: hertuzumab against the prominent tumor target-HER2, monomethyl auristatin E (MMAE) and a cleavable linker. Preclinical studies have demonstrated its robust antitumor activity in BC patient-derived xenograft models with HER2-positive or HER2-low expression. Additionally, antiangiogenic drugs like bevacizumab have shown potential efficacy on advanced BC via inhibiting pathological neovascularizationits.

Case presentation

Here, we will share our experience in treating a 49-year-old woman initially diagnosed with stage IV breast cancer characterized by hormone receptor (HR)-negativity and HER2-positivity. This complex case entailed brain and liver metastases, and the patient exhibited resistance to various HER2-targeted treatment regimens. Finally, the patient received RC48 plus bevacizumab as the advanced forth-line treatment, which was well tolerated with no observed toxicities. Subsequent radiological assessments revealed remarkable regression in the brain metastatic lesions, classified as having partial response based on the RECIST 1.1 system. The period of progression-free survival (PFS) was 7 months.

Conclusion

The present study underscores the efficacy of systemic treatment with RC48 in conjunction, showcasing substantial enhancement in both radiographic indicators and clinical symptomatology among patients with brain metastatic breast cancer (BMBC). More specifically, the sequential application of ADCs in combination with antiangiogenics presents a novel avenue for advancing the treatment landscape of metastatic BC.

Phenotypic and functional analysis in HER2+ targeted therapy of human NK cell subpopulation according to the expression of FcεRIγ and NKG2C in breast cancer patients

Adaptive NK cells constitute an NK cell subpopulation, which expands after human cytomegalovirus (HCMV) infection. This subpopulation has stronger production of cytokines after CD16 stimulation, longer life and persistence than conventional NK cells and are, therefore, interesting tools for cancer immunotherapy. Since there is limited information on adaptive NK cells in cancer patients, we described this population phenotypically and functionally, by flow cytometry, in the context of HER2 + breast cancer (BC) directed therapy. We assessed HCMV status in 78 patients with BC. We found that, similarly to healthy donors (HD), a high proportion of BC patients were HCMV-positive, and nearly 72% of them had an adaptive NK cell subpopulation characterized by the loss of FcεRIγ intracellular adaptor protein or the presence of NKG2C receptor. However, in BC patients, FcεRIγ-  and NKG2C + NK cell populations overlapped to a lesser extent than in HD. Otherwise, no profound phenotypic differences were found between BC patients and HD. Although FcεRIγ-  or NKG2C + NK cell subsets from BC patients produced more IFN-γ than their FcεRIγ + or NKG2C-  NK cell counterparts, IFN-γ production increased only when NK cells simultaneously expressed FcεRIγ- and NKG2C + , whereas in HD the presence of NKG2C marker was sufficient to display greater functionality. Furthermore, in a group of patients treated with chemotherapy and Trastuzumab plus Pertuzumab, FcεRIγ-NKG2C + and FcεRIγ-NKG2C- NK cells retained greater functionality after treatment than FcεRIγ + NKG2C-  NK cells. These results suggest that the presence or magnitude of adaptive NK cell subsets might serve as a key determinant for therapeutic approaches based on antibodies directed against tumor antigens.

HER2-Positive Gastric Cancer: The Role of Immunotherapy and Novel Therapeutic Strategies

Gastric cancer is an aggressive disease with increasing global incidence in recent years. Human epidermal growth receptor 2 (HER2) is overexpressed in approximately 10-20% of gastric cancers. The implementation of targeted therapy against HER2 as part of the standard of care treatment in metastatic disease has improved the prognosis of this subset of patients. However, gastric cancer still has high mortality rates and urgently requires new treatment strategies. The combination of immunotherapy with HER2-targeted therapies has shown synergistic effects in preclinical models, this being the rationale behind exploring this combination in clinical trials in locally advanced and metastatic settings. Additionally, the irruption of antibody-drug conjugates and other novel HER2-targeted agents has led to the development of numerous clinical trials showing promising results. This review presents the molecular mechanisms supporting the use of HER2-targeted drugs in combination with immunotherapy and provides an overview of the therapeutic scenario of HER2-positive disease. We focus on the role of immunotherapy but also summarize emerging therapies and combinations under clinical research that may change the standard treatment in HER-2 positive disease in the future.

Tucatinib promotes immune activation and synergizes with programmed cell death-1 and programmed cell death-ligand 1 inhibition in HER2-positive breast cancer

BACKGROUND

Programmed cell death-1 (PD-1) and programmed cell death-ligand 1 (PD-L1) inhibitors have poor efficacy in patients with trastuzumab-resistant advanced HER2-positive breast cancer. Tucatinib is a potent, selective anti-HER2 tyrosine kinase inhibitor with proven clinical benefit in the advanced setting in patients with trastuzumab resistance. We investigated if tucatinib can alter the tumor microenvironment and if this could be harnessed for therapeutic efficacy.

METHODS

We investigated the antitumor efficacy and contribution of the immune response of tucatinib using 2 immunocompetent, HER2-positive murine breast cancer models (trastuzumab-sensitive H2N113; trastuzumab-resistant Fo5) and the efficacy of tucatinib with trastuzumab and PD-1 or PD-L1 checkpoint inhibitors.

RESULTS

In both models, tucatinib statistically significantly inhibited tumor growth and demonstrated dose-dependent efficacy. Ex vivo analysis by flow cytometry of tumor-infiltrating lymphocytes in mice treated with tucatinib showed increased frequency, higher proliferation, and enhanced effector function of CD8+ effector memory T cells. Tucatinib treatment also increased frequency of CD8+PD-1+ and CD8+TIM3+ T cells, CD49+ natural killer cells, monocytes, and major histocompatibility complex II expression on dendritic cells and macrophages and a decrease in myeloid-derived suppressor cells. Gene expression analysis revealed statistically significant enrichment in pathways associated with immune activation, type I and II interferon response, adaptive immune response, and antigen receptor signaling. In vivo, tucatinib and α-PD-L1 or α-PD-1 demonstrated statistically significantly increased efficacy and improved survival of mice compared with tucatinib alone.

CONCLUSION

Tucatinib modulates the immune microenvironment favorably, and combination treatment with α-PD-L1 or α-PD-1 demonstrated increased efficacy in preclinical HER2-positive tumor models. These findings provide a rationale for investigation of tucatinib and immune checkpoint inhibition in the clinic.

Molecular Pathways and Mechanisms of HER2 in Cancer Therapy

The oncogene ERBB2 encoding the receptor tyrosine-protein kinase erbB-2 (HER2) is frequently overexpressed or amplified and occasionally mutated in a variety of human cancers. The early discovery of this oncogene, its established oncogenic relevance in diverse cancers, its substantial expression on the surface of cancer cells, and its druggable catalytic activity have made it one of the most pursued targets in the history of cancer drug development. Initiatives targeting HER2 provided the early stimulus for several transformational pharmaceutical technologies, including mAbs, tyrosine kinase inhibitors, antibody-drug conjugates, and others. The seismic impact of these efforts has been felt in treatment of many cancers, including breast, gastroesophageal, lung, colorectal, and others. This impact continues to broaden with increasing indications on the horizon and a plethora of novel agents in development. However, implementation of these therapeutic strategies has been complex. The clinical translation of every one of these classes of agents has been notable for underperformance or overperformance characteristics that have informed new lines of research providing deeper insights into the mechanistic complexities and unrealized opportunities provided by this molecular target. Despite all the successes to date, the preponderance of scientific evidence indicates that the full potential of HER2 as a target for cancer therapeutics is far greater than currently realized, and numerous lines of investigation are ongoing to deepen and broaden the scope of impact of HER2 as a signaling, homing, or immunologic target. In this review, we explore the existing data and evolving paradigms surrounding this remarkable target for cancer therapy.

Next generation immuno-oncology biomarkers in gastrointestinal cancer: what does the future hold?

INTRODUCTION

Gastrointestinal (GI) cancers pose a significant health burden worldwide, necessitating advancements in diagnostic and treatment approaches. One promising avenue is the utilization of next-generation biomarkers, which hold the potential to revolutionize GI cancer management.

AREAS COVERED

This review explores the latest breakthroughs and expert opinions surrounding the application of next-generation immunotherapy biomarkers. It encompasses various aspects of the currently utilized biomarkers of immunotherapy in the context of GI cancers focusing on microsatellite stable cancers. It explores the promising research on the next generation of biomarkers addressing the challenges associated with integrating them into clinical practice and the need for standardized protocols and regulatory guidelines.

EXPERT OPINION

Immune profiling, multiplex immunohistochemistry, analysis of immune cell subsets, and novel genomic and epigenomic markers integrated with machine-learning approaches offer new avenues for identifying robust biomarkers. Liquid biopsy-based approaches, such as circulating tumor DNA (ctDNA) and exosome-based analyses, hold promise for real-time monitoring and early detection of treatment response.

Unleashing NK- and CD8 T cells by combining monalizumab and trastuzumab for metastatic HER2-positive breast cancer: Results of the MIMOSA trial

The large majority of patients with HER2-positive metastatic breast cancer (MBC) will eventually develop resistance to anti-HER2 therapy and die of this disease. Despite, relatively high levels of stromal tumor infiltrating lymphocytes (sTILs), PD1-blockade has only shown modest responses. Monalizumab targets the inhibitory immune checkpoint NKG2A, thereby unleashing NK- and CD8 T cells. We hypothesized that monalizumab synergizes with trastuzumab by promoting antibody-dependent cell-mediated cytotoxicity. In the phase II MIMOSA-trial, HER2-positive MBC patients were treated with trastuzumab and 750 mg monalizumab every two weeks. Following a Simon's two-stage design, 11 patients were included in stage I of the trial. Treatment was well tolerated with no dose-limiting toxicities. No objective responses were observed. Therefore, the MIMOSA-trial did not meet its primary endpoint. In summary, despite the strong preclinical rationale, the novel combination of monalizumab and trastuzumab does not induce objective responses in heavily pre-treated HER2-positive MBC patients.

Immunotherapy in Biliary Tract Cancers: Current Standard-of-Care and Emerging Strategies

Biliary tract cancers (BTCs), comprising intrahepatic, perihilar, and distal cholangiocarcinoma as well as gallbladder adenocarcinoma, continue to be challenging to manage. Conventional chemotherapy regimens for advanced disease are limited in both options and benefits, and more effective perioperative regimens are also needed. Over the last decade, immunotherapy has had a profound impact on the management of many solid tumor types, particularly in using immune checkpoint inhibition to enable a tumor-directed T cell response. Immunotherapy administered on its own has had limited utility in BTCs, in part due to a hostile immune microenvironment and the relative infrequency of biomarker-based tumor-agnostic indications for immunotherapy. However, immunotherapy in conjunction with chemotherapy, molecularly targeted therapies, and/or anti-angiogenic therapies has gained traction, supported by evidence that these agents can impart favorable immunomodulatory effects on the tumor microenvironment. The TOPAZ-1 trial led to the first BTC-specific immunotherapy approval, establishing the combination of durvalumab with gemcitabine and cisplatin as the preferred first-line treatment for advanced or metastatic disease. Recently, the KEYNOTE-966 trial showed positive results for the combination of pembrolizumab with gemcitabine and cisplatin in the same setting, adding further evidence for the addition of immune checkpoint inhibition to the standard chemotherapy backbone. Meanwhile, advances in the molecular profiling of BTCs has contributed to the recent proliferation of molecularly targeted therapeutics for the subset of BTCs harboring alterations in IDH1, FGFR2, MAP kinase signaling, HER2, and beyond, and there has been great interest in investigating combinations of these agents with immunotherapy. Emerging immunotherapy strategies beyond immune checkpoint inhibition are also being studied in BTCs, and these include immunostimulatory receptor agonists, Wnt signaling modulators, adoptive cell therapy, and cancer vaccines. A large number of trials are underway to explore promising new combinations and immune-targeted strategies, offering opportunities to expand the role of immunotherapy in BTC management in the near future.

Targeting CXCR4 abrogates resistance to trastuzumab by blocking cell cycle progression and synergizes with docetaxel in breast cancer treatment

BACKGROUND

Although trastuzumab and other HER2-targeted therapies have significantly improved survival in patients with HER2 overexpressed or amplified (HER2+) breast cancer, a significant proportion of patients do not respond or eventually develop clinical resistance. Strategies to reverse trastuzumab resistance remain a high clinical priority. We were the first to report the role of CXCR4 in trastuzumab resistance. The present study aims to explore the therapeutic potential of targeting CXCR4 and better understand the associated mechanisms.

METHODS

Immunofluorescent staining, confocal microscopy analysis, and immunoblotting were used to analyze CXCR4 expression. BrdU incorporation assays and flow cytometry were used to analyze dynamic CXCR4 expression. Three-dimensional co-culture (tumor cells/breast cancer-associated fibroblasts/human peripheral blood mononuclear cells) or antibody-dependent cellular cytotoxicity assay was used to mimic human tumor microenvironment, which is necessary for testing therapeutic effects of CXCR4 inhibitor or trastuzumab. The FDA-approved CXCR4 antagonist AMD3100, trastuzumab, and docetaxel chemotherapy were used to evaluate therapeutic efficacy in vitro and in vivo. Reverse phase protein array and immunoblotting were used to discern the associated molecular mechanisms.

RESULTS

Using a panel of cell lines and patient breast cancer samples, we confirmed CXCR4 drives trastuzumab resistance in HER2+ breast cancer and further demonstrated the increased CXCR4 expression in trastuzumab-resistant cells is associated with cell cycle progression with a peak in the G2/M phases. Blocking CXCR4 with AMD3100 inhibits cell proliferation by downregulating mediators of G2-M transition, leading to G2/M arrest and abnormal mitosis. Using a panel of trastuzumab-resistant cell lines and an in vivo established trastuzumab-resistant xenograft mouse model, we demonstrated that targeting CXCR4 with AMD3100 suppresses tumor growth in vitro and in vivo, and synergizes with docetaxel.

CONCLUSIONS

Our findings support CXCR4 as a novel therapeutic target and a predictive biomarker for trastuzumab resistance in HER2+ breast cancer.

Individualizing Curative-Intent Therapy in HER2-Positive Early-Stage Breast Cancer

OPINION STATEMENT

Human epidermal growth factor receptor 2-positive (HER2+) breast cancers have been historically considered an aggressive entity with high rates of recurrence and poor survival. However, during the last 20 years, there has been a dramatic change in prognosis due to the incorporation of different anti-HER2 therapies into the neo/adjuvant chemotherapy backbone. Neoadjuvant dual blockade with trastuzumab and pertuzumab has become the standard of care for women with stage II and III HER2+ breast cancer. Trastuzumab emtansine (T-DM1) has been shown to improve outcomes if pathological complete response (pCR) is not achieved, and adjuvant extended therapy with neratinib has increased disease-free survival (DFS) and may have an impact in central nervous system (CNS) recurrences. However, these agents are both toxic for individual patients and costly for the overall healthcare system, and there are still patients that experience recurrence despite therapy improvements. At the same time, it has been shown that some patients with early-stage HER2+ breast cancer can be effectively treated with less intensive systemic therapy, using only taxane and trastuzumab, or that the chemotherapy backbone can be omitted completely. The current challenge is to properly identify which patients can receive a de-intensified regimen and which need new intensification strategies. Tumor size, nodal status, and pCR achievement after neoadjuvant treatment are well-known risk factors that can aid in making clinical decisions, but they do not accurately predict all patient outcomes. Various biomarkers have been proposed to better characterize the clinical and biological heterogeneity of HER2+ breast cancer. Immune infiltration, intrinsic subtype, intratumoral heterogeneity, and dynamic changes during treatment have been described as important prognostic and/or predictive features. The integration of all these factors will be key in the proper identification of the true risk, and individualized treatment strategy, for each patient.

Emerging Targeted Therapies for HER2-Positive Breast Cancer

Breast cancer is the most common cancer in women and the leading cause of death. HER2 overexpression is found in approximately 20% of breast cancers and is associated with a poor prognosis and a shorter overall survival. Tratuzumab, a monoclonal antibody directed against the HER2 receptor, is the standard of care treatment. However, a third of the patients do not respond to therapy. Given the high rate of resistance, other HER2-targeted strategies have been developed, including monoclonal antibodies such as pertuzumab and margetuximab, trastuzumab-based antibody drug conjugates such as trastuzumab-emtansine (T-DM1) and trastuzumab-deruxtecan (T-DXd), and tyrosine kinase inhibitors like lapatinib and tucatinib, among others. Moreover, T-DXd has proven to be of use in the HER2-low subtype, which suggests that other HER2-targeted therapies could be successful in this recently defined new breast cancer subclassification. When patients progress to multiple strategies, there are several HER2-targeted therapies available; however, treatment options are limited, and the potential combination with other drugs, immune checkpoint inhibitors, CAR-T cells, CAR-NK, CAR-M, and vaccines is an interesting and appealing field that is still in development. In this review, we will discuss the highlights and pitfalls of the different HER2-targeted therapies and potential combinations to overcome metastatic disease and resistance to therapy.

Immunotherapy for HER-2 positive breast cancer

Immunotherapy is a developing treatment for advanced breast cancer. Immunotherapy has clinical significance for the treatment of triple-negative breast cancers and human epidermal growth factor receptor-2 positive (HER2+) breast cancers. As a proved effective passive immunotherapy, clinical application of the monoclonal antibodies trastuzumab, pertuzumab and T-DM1 (ado-trastuzumab emtansine) has significantly improved the survival of patients with HER2+ breast cancers. Immune checkpoint inhibitors that block programmed death receptor-1 and its ligand (PD-1/PD-L1) have also shown benefits for breast cancer in various clinical trials. Adoptive T-cell immunotherapies and tumor vaccines are emerging as novel approaches to treating breast cancer, but require further study. This article reviews recent advances in immunotherapy for HER2+ breast cancers.

Real-world clinical outcomes of the combination of anti-PD-1 antibody, trastuzumab, and chemotherapy for HER2-positive gastric/gastroesophageal junction cancer

BACKGROUND

Previous clinical trials indicated the addition of anti-PD-1 antibody remarkably improved the efficacy of trastuzumab and chemotherapy in patients with HER2-positive gastric/gastroesophageal junction (GEJ) cancer. However, no real-world experiences have been reported yet.

METHODS

We retrospectively analyzed 1212 patients with gastric/GEJ cancer treated at Nanjing Drum Tower Hospital between 2019 and 2022. Among 138 patients with HER2-positive gastric/GEJ cancer, 47 patients receiving at least two doses of the combination regimen with anti-PD-1 antibody, trastuzumab, and chemotherapy were recruited in the study population, and 38 out of 47 patients with measurable disease were included in the efficacy population. Progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and toxicity profiles were reported.

RESULTS

In the study population, 37 (78.7%) received the study therapy as a first-line treatment. In the efficacy population, the ORR and DCR were 76.3% and 94.7%, respectively. The overall median PFS was 9.1 months (95% confidence interval [CI] 6.3-11.9 months). For the first-line treatment, the mPFS was 10 months, and 7 months for the second-line. Among 14 patients who failed the study treatment, three (21.4%) developed brain metastasis as the first failure site. No significant association was found between PFS and the expression of PD-L1. 22.2% of patients developed grade 3 treatment-related adverse events (TRAEs). No treatment-related grade ≥4 adverse events or deaths occurred.

CONCLUSION

This real-world study validated the combination regimen's high efficacy and good tolerance in patients with HER2-positive gastric/GEJ cancer. An increased incidence of brain metastasis was observed in patients who failed this regimen.

Blocking soluble TNFα sensitizes HER2-positive breast cancer to trastuzumab through MUC4 downregulation and subverts immunosuppression

BACKGROUND

The success of HER2-positive (HER2+) breast cancer treatment with trastuzumab, an antibody that targets HER2, relies on immune response. We demonstrated that TNFα induces mucin 4 (MUC4) expression, which shields the trastuzumab epitope on the HER2 molecule decreasing its therapeutic effect. Here, we used mouse models and samples from HER2+ breast cancer patients to unravel MUC4 participation in hindering trastuzumab effect by fostering immune evasion.

METHODS

We used a dominant negative TNFα inhibitor (DN) selective for soluble TNFα (sTNFα) together with trastuzumab. Preclinical experiments were performed using two models of conditionally MUC4-silenced tumors to characterize the immune cell infiltration. A cohort of 91 patients treated with trastuzumab was used to correlate tumor MUC4 with tumor-infiltrating lymphocytes.

RESULTS

In mice bearing de novo trastuzumab-resistant HER2+ breast tumors, neutralizing sTNFα with DN induced MUC4 downregulation. Using the conditionally MUC4-silenced tumor models, the antitumor effect of trastuzumab was reinstated and the addition of TNFα-blocking agents did not further decrease tumor burden. DN administration with trastuzumab modifies the immunosuppressive tumor milieu through M1-like phenotype macrophage polarization and NK cells degranulation. Depletion experiments revealed a cross-talk between macrophages and NK cells necessary for trastuzumab antitumor effect. In addition, tumor cells treated with DN are more susceptible to trastuzumab-dependent cellular phagocytosis. Finally, MUC4 expression in HER2+ breast cancer is associated with immune desert tumors.

CONCLUSIONS

These findings provide rationale to pursue sTNFα blockade combined with trastuzumab or trastuzumab drug conjugates for MUC4+ and HER2+ breast cancer patients to overcome trastuzumab resistance.

Targeting CXCR4 abrogates resistance to trastuzumab by blocking cell cycle progression and synergizes with docetaxel in breast cancer treatment

Background: Although trastuzumab and other HER2-targeted therapies have significantly improved survival in patients with HER2 overexpressed or amplified (HER2+) breast cancer, a significant proportion of patients do not respond or eventually develop clinical resistance. Strategies to reverse trastuzumab resistance remain a high clinical priority. We were the first to report the role of CXCR4 in trastuzumab resistance. The present study aims to explore the therapeutic potential of targeting CXCR4 and better understand the associated mechanisms. Methods: Immunofluorescent staining, confocal microscopy analysis, and immunoblotting were used to analyze CXCR4 expression. BrdU incorporation assays and flow cytometry were used to analyze dynamic CXCR4expression. Three-dimensional co-culture (tumor cells/ breast cancer-associated fibroblasts / human peripheral blood mononuclear cells) or antibody-dependent cellular cytotoxicity assay was used to mimic human tumor microenvironment, which is necessary for testing therapeutic effect of CXCR4 inhibitor or trastuzumab. The FDA-approved CXCR4 antagonist AMD3100, trastuzumab, and docetaxel chemotherapy were used to evaluate therapeutic efficacy in vitro and in vivo. Reverse phase protein array and immunoblotting were used to discern the associated molecular mechanisms. Results: Using multiple cell lines and patient breast cancer samples we confirmed CXCR4 drives trastuzumab resistance in HER2+ breast cancer and further demonstrated that the increased CXCR4 expression in trastuzumab-resistant cells is associated with cell cycle progression with a peak in the G2/M phases. Blocking CXCR4 with AMD3100 inhibits cell proliferation by downregulating mediators of G2-M transition, leading to G2/M arrest and abnormal mitosis. Using multiple trastuzumab-resistant cell lines and an in vivo established trastuzumab-resistant xenograft mouse model, we demonstrated that targeting CXCR4 with AMD3100 suppresses tumor growth in vitro and in vivo, and synergizes with docetaxel. Conclusions: Our findings support CXCR4 as a novel therapeutic target and a predictive biomarker for trastuzumab resistance in HER2+ breast cancer.

Mechanisms driving the immunoregulatory function of cancer cells

Tumours display an astonishing variation in the spatial distribution, composition and activation state of immune cells, which impacts their progression and response to immunotherapy. Shedding light on the mechanisms that govern the diversity and function of immune cells in the tumour microenvironment will pave the way for the development of more tailored immunomodulatory strategies for the benefit of patients with cancer. Cancer cells, by virtue of their paracrine and juxtacrine communication mechanisms, are key contributors to intertumour heterogeneity in immune contextures. In this Review, we discuss how cancer cell-intrinsic features, including (epi)genetic aberrations, signalling pathway deregulation and altered metabolism, play a key role in orchestrating the composition and functional state of the immune landscape, and influence the therapeutic benefit of immunomodulatory strategies. Moreover, we highlight how targeting cancer cell-intrinsic parameters or their downstream immunoregulatory pathways is a viable strategy to manipulate the tumour immune milieu in favour of antitumour immunity.

Nanotechnology: A revolutionary approach to prevent breast cancer recurrence

Breast cancer is the most prevalent malignancy in women worldwide and one of the deadliest after lung cancer. Currently, standard treatment approaches for breast cancers are surgery accompanied by chemotherapy or radiotherapy. Cancer local recurrence after mastectomy is commonly considered as being a poor prognostic predictor. There have been advancements in the procedures utilized for breast reconstruction following mastectomy, much as there have been advancements in the early diagnosis and treatment of breast cancer. For the last decade, developing nanotechnology applications for cancer therapies has had much focus. The benefits granted by nanotechnologies via enhancing biological processes and promoting better biomaterial compatibility, as well as generating functionalized tissues, transpire exciting possibilities. Modified nanomedicine may introduce tremendous improvements to the fields of breast cancer recurrence through implants. It can modify the surfaces of implants to optimize tissue growth, thus minimizing inflammation and unsatisfactory results. Here we discuss new nanotechnology advancements and incorporate them into breast reconstruction surgeries following mastectomy or lumpectomy. In addtion, we repurpose old technologies, like growth factor therapies using nanotechnology for more efficient delivery.

Innovative Therapeutic Approaches for Patients with HER2-Positive Breast Cancer

Overexpression of human epidermal growth factor receptor 2 (HER2), a transmembrane tyrosine kinase receptor, has been described in about 15-20% of breast cancer (BC) and is associated with poor outcomes. Trastuzumab is the first anti-HER2 monoclonal antibody (mAB) that blocks receptor activity but it also activates immune response against cancer cells, thus, revolutionizing the prognosis of patients with HER2-positive BC. Over the years, new therapies have been developed, including other mAbs and tyrosine kinase inhibitors (TKIs) that required multimodal approaches with chemotherapy to optimize their anticancer activity. This chapter gives a comprehensive overview of the last advancements including new approaches and future combinations, which seem to be very promising in overcoming resistance to the traditional anti-HER2 treatments. A modern therapeutic algorithm should include treatment options based on tumour patterns and a patient-centred approach. A proper patient's selection is crucial to derive maximal benefits from a treatment strategy and emerging biomarkers should be integrated along with the HER2 status, which is currently the only validated biomarker in the context of HER2-positive disease. These biomarkers might include molecular features with reported prognostic/predictive significance, such as phosphatidylinositol 3' -kinase (PI3K) or mitogen-activated protein kinase (MAPK) pathways, programmed cell death protein ligand 1 (PD-L1), and tumour-infiltrating lymphocytes (TILs), which all affect prognosis and response to treatments.

Activation of B cells in Tertiary Lymphoid Structures in cancer: Anti-tumor or anti-self?

Whereas T cells in the tumor microenvironment have been the main focus as cancer controlling cells and targets of immunotherapies, B cells have recently gained strong attention. Being associated to Tertiary Lymphoid Structures (TLS) located at the vicinity of tumor nests, the fate of B cell depends on TLS maturity. In immature TLS they may evolve as regulatory B cells producing immunosuppressive cytokines and promote tumor growth. In mature TLS with a germinal center, B cells are selected, amplified, undergo affinity maturation and isotypic switching, resulting in plasma cell generation and production of anti-tumor antibodies. In that case, they are associated with longer patient's survival and therapeutic response to immunotherapy. Identification of tumor specific, or tumor overexpressed, antigens recognized by "in situ" produced antibodies and their discrimination from self-antigens induced by ICI treatments is a major challenge to develop novel antibody-based immunotherapies.

Tumor-Infiltrating Lymphocytes and Immune Response in HER2-Positive Breast Cancer

Human epidermal growth factor receptor 2-positive (HER2-positive) breast cancer accounts for 15 to 25% of breast cancer cases. Although therapies based on the use of monoclonal anti-HER2 antibodies present clinical benefit for a subtype of patients with HER2-positive breast cancer, more than 50% of them are unresponsive to targeted therapies or they eventually relapse. In recent years, reactivation of the adaptive immune system in patients with solid tumors has emerged as a therapeutic option with great potential for clinical benefit. Since the approval of the first treatment directed against HER2 as a therapeutic target, the range of clinical options has expanded greatly, and, in this sense, cellular immunotherapy with T cells relies on the cytotoxicity generated by these cells, which ultimately leads to antitumor activity. Lymphocytic infiltration of tumors encompasses a heterogeneous population of immune cells within the tumor microenvironment that exhibits distinct patterns of immune activation and exhaustion. The prevalence and prognostic value of tumor-infiltrating lymphocyte (TIL) counts are associated with a favorable prognosis in HER2-positive breast cancers. This review discusses emerging findings that contribute to a better understanding of the role of immune infiltrates in HER2-positive breast cancer. In addition, it summarizes the most recent results in HER2-positive breast cancer immunotherapy and anticipates which therapeutic strategies could be applied in the immediate future.

Chemotherapy Dose Shapes the Expression of Immune-Interacting Markers on Cancer Cells

Introduction

Tumor and immune cells interact through a variety of cell-surface proteins that can either restrain or promote tumor progression. The impacts of cytotoxic chemotherapy dose and delivery route on this interaction profile remain incompletely understood, and could support the development of more effective combination therapies for cancer treatment.

Methods and Results

Here, we found that exposure to the anthracycline doxorubicin altered the expression of numerous immune-interacting markers (MHC-I, PD-L1, PD-L2, CD47, Fas, and calreticulin) on live melanoma, breast cancer, and leukemia cells in a dose-dependent manner in vitro. Notably, an intermediate dose best induced immunogenic cell death and the expression of immune-activating markers without maximizing expression of markers associated with immune suppression. Bone marrow-derived dendritic cells exposed to ovalbumin-expressing melanoma treated with intermediate doxorubicin dose became activated and best presented tumor antigen. In a murine melanoma model, both the doxorubicin dose and delivery location (systemic infusion versus local administration) affected the expression of these markers on live tumor cells. Particularly, local release of doxorubicin from a hydrogel increased calreticulin expression on tumor cells without inducing immune-suppressive markers, in a manner dependent on the loaded dose. Doxorubicin exposure also altered the expression of immune-interacting markers in patient-derived melanoma cells.

Conclusions

Together, these results illustrate how standard-of-care chemotherapy, when administered in various manners, can lead to distinct expression of immunogenic markers on cancer cells. These findings may inform development of chemo-immunotherapy combinations for cancer treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-022-00742-y.