Hallmarks of Resistance to Immune-Checkpoint Inhibitors

Deciphering CD4+ T cell-mediated responses against cancer

It's been long thought that CD8+ cytotoxic T cells play a major role in T cell-mediated antitumor responses, whereas CD4+ T cells merely provide some assistance to CD8+ T cells as the "helpers." In recent years, numerous studies support the notion that CD4+ T cells play an indispensable role in antitumor responses. Here, we summarize and discuss the current knowledge regarding the roles of CD4+ T cells in antitumor responses and immunotherapy, with a focus on the molecular and cellular mechanisms behind these observations. These new insights on CD4+ T cells may pave the way to further optimize cancer immunotherapy.

Beyond Anti-PD-1/PD-L1: Improving Immune Checkpoint Inhibitor Responses in Triple-Negative Breast Cancer

The introduction of anti-programmed cell death protein-1 (anti-PD-1) to the clinical management of triple-negative breast cancer (TNBC) represents a breakthrough for a disease whose treatment has long relied on the standards of chemotherapy and surgery. Nevertheless, few TNBC patients achieve a durable remission in response to anti-PD-1, and there is a need to develop strategies to maximize the potential benefit of immune checkpoint inhibition (ICI) for TNBC patients. In the present review, we discuss three conceptual strategies to improve ICI response rates in TNBC patients. The first effort involves improving patient selection. We discuss proposed biomarkers of response and resistance to anti-PD-1, concluding that an optimal biomarker will likely be multifaceted. The second effort involves identifying existing targeted therapies or chemotherapies that may synergize with ICI. In particular, we describe recent efforts to use inhibitors of the PI3K/AKT or RAS/MAPK/ERK pathways in combination with ICI. Third, considering the possibility that targeting the PD-1 axis is not the most promising strategy for TNBC treatment, we describe ongoing efforts to identify novel immunotherapy strategies.

Current and future immunotherapeutic approaches in pancreatic cancer treatment

Pancreatic cancer is a major cause of cancer-related death, but despondently, the outlook and prognosis for this resistant type of tumor have remained grim for a long time. Currently, it is extremely challenging to prevent or detect it early enough for effective treatment because patients rarely exhibit symptoms and there are no reliable indicators for detection. Most patients have advanced or spreading cancer that is difficult to treat, and treatments like chemotherapy and radiotherapy can only slightly prolong their life by a few months. Immunotherapy has revolutionized the treatment of pancreatic cancer, yet its effectiveness is limited by the tumor's immunosuppressive and hard-to-reach microenvironment. First, this article explains the immunosuppressive microenvironment of pancreatic cancer and highlights a wide range of immunotherapy options, including therapies involving oncolytic viruses, modified T cells (T-cell receptor [TCR]-engineered and chimeric antigen receptor [CAR] T-cell therapy), CAR natural killer cell therapy, cytokine-induced killer cells, immune checkpoint inhibitors, immunomodulators, cancer vaccines, and strategies targeting myeloid cells in the context of contemporary knowledge and future trends. Lastly, it discusses the main challenges ahead of pancreatic cancer immunotherapy.

A computational pipeline for identifying gene targets and signalling pathways in cancer cells to improve lymphocyte infiltration and immune checkpoint therapy efficacy

BACKGROUND

Tumour-infiltrating lymphocytes (TILs) are crucial for effective immune checkpoint blockade (ICB) therapy in solid tumours. However, ∼70% of these tumours exhibit poor lymphocyte infiltration, rendering ICB therapies less effective.

METHODS

We developed a bioinformatics pipeline integrating multiple previously unconsidered factors or datasets, including tumour cell immune-related pathways, copy number variation (CNV), and single tumour cell sequencing data, as well as tumour mRNA-seq data and patient survival data, to identify targets that can potentially improve T cell infiltration and enhance ICB efficacy. Furthermore, we conducted wet-lab experiments and successfully validated one of the top-identified genes.

FINDINGS

We applied this pipeline in solid tumours of the Cancer Genome Atlas (TCGA) and identified a set of genes in 18 cancer types that might potentially improve lymphocyte infiltration and ICB efficacy, providing a valuable drug target resource to be further explored. Importantly, we experimentally validated SUN1, which had not been linked to T cell infiltration and ICB therapy previously, but was one of the top-identified gene targets among 3 cancer types based on the pipeline, in a mouse colon cancer syngeneic model. We showed that Sun1 KO could significantly enhance antigen presentation, increase T-cell infiltration, and improve anti-PD1 treatment efficacy. Moreover, with a single-cell multiome analysis, we identified subgene regulatory networks (sub-GRNs) showing Stat proteins play important roles in enhancing the immune-related pathways in Sun1-KO cancer cells.

INTERPRETATION

This study not only established a computational pipeline for discovering new gene targets and signalling pathways in cancer cells that block T-cell infiltration, but also provided a gene target pool for further exploration in improving lymphocyte infiltration and ICB efficacy in solid tumours.

FUNDING

A full list of funding bodies that contributed to this study can be found in the Acknowledgements section.

Assessment of cancer cell-expressed HLA class I molecules and their immunopathological implications

Immunotherapy using immune checkpoint inhibitors (ICIs) has shown superior efficacy compared with conventional chemotherapy in certain cancer types, establishing immunotherapy as the fourth standard treatment alongside surgical intervention, chemotherapy, and radiotherapy. In cancer immunotherapy employing ICIs, CD8-positive cytotoxic T lymphocytes are recognized as the primary effector cells. For effective clinical outcomes, it is essential that the targeted cancer cells express HLA class I molecules to present antigenic peptides derived from the tumor. However, cancer cells utilize various mechanisms to downregulate or lose HLA class I molecules from their surface, resulting in evasion from immune surveillance. Correlations between prognosis and the integrity of HLA class I molecules expressed by cancer cells have been consistently found across different types of cancer. This paper provides an overview of the regulatory mechanisms of HLA class I molecules and their role in cancer immunotherapy, with a particular emphasis on the significance of utilizing pathological tissues to evaluate HLA class I molecules expressed in cancer cells.

Recent advances and remaining challenges in lung cancer therapy

ABSTRACT

Lung cancer remains the most common cause of cancer death. Given the continued research into new drugs and combination therapies, outcomes in lung cancer have been improved, and clinical benefits have been expanded to a broader patient population. However, the overall cure and survival rates for lung cancer patients remain low, especially in metastatic cases. Among the available lung cancer treatment options, such as surgery, radiation therapy, chemotherapy, targeted therapies, and alternative therapies, immunotherapy has shown to be the most promising. The exponential progress in immuno-oncology research and recent advancements made in the field of immunotherapy will further increase the survival and quality of life for lung cancer patients. Substantial progress has been made in targeted therapies using tyrosine kinase inhibitors and monoclonal antibody immune checkpoint inhibitors with many US Food And Drug Administration (FDA)-approved drugs targeting the programmed cell death ligand-1 protein (e.g., durvalumab, atezolizumab), the programmed cell death-1 receptor (e.g., nivolumab, pembrolizumab), and cytotoxic T-lymphocyte-associated antigen 4 (e.g., tremelimumab, ipilimumab). Cytokines, cancer vaccines, adoptive T cell therapies, and Natural killer cell mono- and combinational therapies are rapidly being studied, yet to date, there are currently none that are FDA-approved for the treatment of lung cancer. In this review, we discuss the current lung cancer therapies with an emphasis on immunotherapy, including the challenges for future research and clinical applications.

Antibody Drug Clearance: An Underexplored Marker of Outcomes with Checkpoint Inhibitors

Immune-checkpoint inhibitor (ICI) therapy has dramatically changed the clinical landscape for several cancers, and ICI use continues to expand across many cancer types. Low baseline clearance (CL) and/or a large reduction of CL during treatment correlates with better clinical response and longer survival. Similar phenomena have also been reported with other monoclonal antibodies (mAb) in cancer and other diseases, highlighting a characteristic of mAb clinical pharmacology that is potentially shared among various mAbs and diseases. Though tempting to attribute poor outcomes to low drug exposure and arguably low target engagement due to high CL, such speculation is not supported by the relatively flat exposure-response relationship of most ICIs, where a higher dose or exposure is not likely to provide additional benefit. Instead, an elevated and/or increasing CL could be a surrogate marker of the inherent resistant phenotype that cannot be reversed by maximizing drug exposure. The mechanisms connecting ICI clearance, therapeutic efficacy, and resistance are unclear and likely to be multifactorial. Therefore, to explore the potential of ICI CL as an early marker for efficacy, this review highlights the similarities and differences of CL characteristics and CL-response relationships for all FDA-approved ICIs, and we compare and contrast these to selected non-ICI mAbs. We also discuss underlying mechanisms that potentially link mAb CL with efficacy and highlight existing knowledge gaps and future directions where more clinical and preclinical investigations are warranted to clearly understand the value of baseline and/or time-varying CL in predicting response to ICI-based therapeutics.

Discovering the strength of immunometabolism in cancer therapy: Employing metabolic pathways to enhance immune responses

Immunometabolism, which studies cellular metabolism and immune cell function, is a possible cancer treatment. Metabolic pathways regulate immune cell activation, differentiation, and effector functions, crucial to tumor identification and elimination. Immune evasion and tumor growth can result from tumor microenvironment metabolic dysregulation. These metabolic pathways can boost antitumor immunity. This overview discusses immune cell metabolism, including glycolysis, oxidative phosphorylation, amino acid, and lipid metabolism. Amino acid and lipid metabolic manipulations may improve immune cell activity and antitumor immunity. Combination therapy using immunometabolism-based strategies may enhance therapeutic efficacy. The complexity of the metabolic network, biomarker development, challenges, and future approaches are all covered, along with a summary of case studies demonstrating the effectiveness of immunometabolism-based therapy. Metabolomics, stable isotope tracing, single-cell analysis, and computational modeling are also reviewed for immunometabolism research. Personalized and combination treatments are considered. This review adds to immunometabolism expertise and sheds light on metabolic treatments' ability to boost cancer treatment immunological response. Also, in this review, we discussed the immune response in cancer treatment and altering metabolic pathways to increase the immune response against malignancies.

Tumor Copy Number Alteration Burden as a Predictor for Resistance to Immune Checkpoint Blockade across Different Cancer Types

Immune checkpoint blockade (ICB) benefits only a subset of advanced cancer patients, and predictive biomarkers for immunotherapy response are needed. Recently, copy number alteration (CNA) burden has been proposed to predict ICB resistance. We assessed this finding using the publicly accessible data for 1661 ICB-treated patients whose tumors were profiled by MSK-IMPACT, an approved targeted assay in clinical care. We tested the hypothesis that the continuous increase in CNA burden is associated with poor overall survival following ICB. In addition, we hypothesized that the combinatorial biomarkers of tumor mutational burden (TMB) and CNA burden would better stratify patients for immune status and ICB response. Of the 1661 cases, 79% (n = 1307) were treated with anti PD-1/PD-L1 and the remaining 21% (n = 354) with anti CTLA-4 or the combination of both. In a multivariate analysis, increase in CNA burden was associated with poor overall survival [HR = 1.52, 95% CI (1.01-2.30), p = 0.04]. The combination of biomarkers TMB and CNA burden stratified patients into four clinically distinct subsets among which "LowTMB/HighCNA" showed the worst survival (p < 0.0001). The four patient subsets had unique CNA profiles and enriched pathways, which could predict transcriptional and phenotypic effects related to immune signaling and CD8+ T-cell abundance in the tumor microenvironment. CNA burden was associated with poor overall survival in patients receiving ICB and could improve patient stratification when incorporated with TMB. These findings may guide patient selection for immunotherapy or alternative strategies.

Immune Escape Strategies in Head and Neck Cancer: Evade, Resist, Inhibit, Recruit

Head and neck cancers (HNCs) arise from the mucosal lining of the aerodigestive tract and are often associated with alcohol use, tobacco use, and/or human papillomavirus (HPV) infection. Over 600,000 new cases of HNC are diagnosed each year, making it the sixth most common cancer worldwide. Historically, treatments have included surgery, radiation, and chemotherapy, and while these treatments are still the backbone of current therapy, several immunotherapies have recently been approved by the Food and Drug Administration (FDA) for use in HNC. The role of the immune system in tumorigenesis and cancer progression has been explored since the early 20th century, eventually coalescing into the current three-phase model of cancer immunoediting. During each of the three phases-elimination, equilibrium, and escape-cancer cells develop and utilize multiple strategies to either reach or remain in the final phase, escape, at which point the tumor is able to grow and metastasize with little to no detrimental interference from the immune system. In this review, we summarize the many strategies used by HNC to escape the immune system, which include ways to evade immune detection, resist immune cell attacks, inhibit immune cell functions, and recruit pro-tumor immune cells.

Centrosomal Protein 55 (CEP55) Drives Immune Exclusion and Resistance to Immune Checkpoint Inhibitors in Colorectal Cancer

Colorectal cancer (CRC) currently ranks as the third most common cancer in the United States, and its incidence is on the rise, especially among younger individuals. Despite the remarkable success of immune checkpoint inhibitors (ICIs) in various cancers, most CRC patients fail to respond due to intrinsic resistance mechanisms. While microsatellite instability-high phenotypes serve as a reliable positive predictive biomarker for ICI treatment, the majority of CRC patients with microsatellite-stable (MSS) tumors remain ineligible for this therapeutic approach. In this study, we investigated the role of centrosomal protein 55 (CEP55) in shaping the tumor immune microenvironment in CRC. CEP55 is overexpressed in multiple cancer types and was shown to promote tumorigenesis by upregulating the PI3K/AKT pathway. Our data revealed that elevated CEP55 expression in CRC was associated with reduced T cell infiltration, contributing to immune exclusion. As CRC tumors progressed, CEP55 expression increased alongside sequential mutations in crucial driver genes (APC, KRAS, TP53, and SMAD4), indicating its involvement in tumor progression. CEP55 knockout significantly impaired tumor growth in vitro and in vivo, suggesting that CEP55 plays a crucial role in tumorigenesis. Furthermore, the CEP55 knockout increased CD8+ T cell infiltration and granzyme B production, indicating improved anti-tumor immunity. Additionally, we observed reduced regulatory T cell infiltration in CEP55 knockout tumors, suggesting diminished immune suppression. Most significantly, CEP55 knockout tumors demonstrated enhanced responsiveness to immune checkpoint inhibition in a clinically relevant orthotopic CRC model. Treatment with anti-PD1 significantly reduced tumor growth in CEP55 knockout tumors compared to control tumors, suggesting that inhibiting CEP55 could improve the efficacy of ICIs. Collectively, our study underscores the crucial role of CEP55 in driving immune exclusion and resistance to ICIs in CRC. Targeting CEP55 emerges as a promising therapeutic strategy to sensitize CRC to immune checkpoint inhibition, thereby improving survival outcomes for CRC patients.

Multistep tumor genetic evolution and changes in immunogenicity trigger immune-mediated disease eradication in stage IV melanoma: lessons from a single case

Durable remissions are observed in 10%-20% of treated patients with advanced metastatic melanoma but the factors associated with long-term complete clinical responses are largely unknown. Here, we report the molecular characteristics of tumor evolution during disease progression along a 9-year clinical course in a patient with advanced disseminated melanoma who received different treatments, including trametinib, ipilimumab, radiation, vemurafenib, surgical tumor debulking and a second ipilimumab course, ultimately achieving complete long-term disease remission.Longitudinal analyses of therapies-resistant metastatic tumors revealed the effects of different treatments on tumor's microenvironment and immunogenicity, ultimately creating a milieu favorable to immunotherapy response. Monitoring of the temporal dynamics of T cells by analysis of the T cell receptor (TCR) repertoire in the tumor and peripheral blood during disease evolution indicated that T-cell clones with common TCR rearrangements, present at low levels at baseline, were maintained and expanded after immunotherapy, and that TCR diversity increased. Analysis of genetic, molecular, and cellular components of the tumor depicted a multistep process in which treatment with kinase inhibitors strongly conditioned the immune microenvironment creating an inflamed milieu converting cold into hot tumors, while ipilimumab impacted and increased the TCR repertoire, a requirement for tumor rejection.Since the optimal sequencing of treatment with antibodies targeting immune checkpoints and kinase inhibitors for advanced melanoma is still clinically debated, this case indicates that immunotherapy success is possible even after progression on targeted therapy.

Nanotechnology Applications in Breast Cancer Immunotherapy

Next-generation cancer treatments are expected not only to target cancer cells but also to simultaneously train immune cells to combat cancer while modulating the immune-suppressive environment of tumors and hosts to ensure a robust and lasting response. Achieving this requires carriers that can codeliver multiple therapeutics to the right cancer and/or immune cells while ensuring patient safety. Nanotechnology holds great potential for addressing these challenges. This article highlights the recent advances in nanoimmunotherapeutic development, with a focus on breast cancer. While immune checkpoint inhibitors (ICIs) have achieved remarkable success and lead to cures in some cancers, their response rate in breast cancer is low. The poor response rate in solid tumors is often associated with the low infiltration of anti-cancer T cells and an immunosuppressive tumor microenvironment (TME). To enhance anti-cancer T-cell responses, nanoparticles are employed to deliver ICIs, bispecific antibodies, cytokines, and agents that induce immunogenic cancer cell death (ICD). Additionally, nanoparticles are used to manipulate various components of the TME, such as immunosuppressive myeloid cells, macrophages, dendritic cells, and fibroblasts to improve T-cell activities. Finally, this article discusses the outlook, challenges, and future directions of nanoimmunotherapeutics.

Revealing Pan-Histology Immunomodulatory Targets in Pediatric Central Nervous System Tumors

BACKGROUND

The application of immunotherapy for pediatric CNS malignancies has been limited by the poorly understood immune landscape in this context. The aim of this study was to uncover the mechanisms of immune suppression common among pediatric brain tumors.

METHODS

We apply an immunologic clustering algorithm validated by The Cancer Genome Atlas Project to an independent pediatric CNS transcriptomic dataset. Within the clusters, the mechanisms of immunosuppression are explored via tumor microenvironment deconvolution and survival analyses to identify relevant immunosuppressive genes with translational relevance.

RESULTS

High-grade diseases fall predominantly within an immunosuppressive subtype (C4) that independently lowers overall survival time and where common immune checkpoints (e.g., PDL1, CTLA4) are less relevant. Instead, we identify several alternative immunomodulatory targets with relevance across histologic diseases. Specifically, we show how the mechanism of EZH2 inhibition to enhance tumor immunogenicity in vitro via the upregulation of MHC class 1 is applicable to a pediatric CNS oncologic context. Meanwhile, we identify that the C3 (inflammatory) immune subtype is more common in low-grade diseases and find that immune checkpoint inhibition may be an effective way to curb progression for this subset.

CONCLUSIONS

Three predominant immunologic clusters are identified across pediatric brain tumors. Among high-risk diseases, the predominant immune cluster is associated with recurrent immunomodulatory genes that influence immune infiltrate, including a subset that impacts survival across histologies.

Xenogeneic equine stem cells activate anti-tumor adaptive immunity in a 4T1-based intraductal mouse model for triple-negative breast cancer: proof-of-principle

Triple-negative breast cancer (TNBC) remains difficult to treat, especially due to ineffective immune responses. Current treatments mainly aim at a cytotoxic effect, whereas (stem) cell therapies are being investigated for their immune stimulatory capacities to initiate the anti-tumor immunity. Here, a thoroughly characterized, homogenous and non-tumorigenic mixture of equine mesenchymal stem cells (eMSCs) harvested from horse peripheral blood as innovative xenogeneic immunomodulators were tested in a 4T1-based intraductal mouse model for TNBC. The eMSCs significantly reduced 4T1 progression upon systemic injection, with induction of inflammatory mediators and T-cell influx in primary tumors, already after a single dose. These xenogeneic anti-cancer effects were not restricted to MSCs as systemic treatment with alternative equine epithelial stem cells (eEpSCs) mimicked the reported disease reduction. Mechanistically, effective eMSC treatment did not rely on the spleen as systemic entrapment site, whereas CD4+ and CD8α+ T-cell infiltration and activation were critical. These results show that eMSCs and potentially also other equine stem cell types can be a valuable TNBC treatment strategy for further (pre)clinical evaluation.

Combinatorial blockade for cancer immunotherapy: targeting emerging immune checkpoint receptors

The differentiation, survival, and effector function of tumor-specific CD8+ cytotoxic T cells lie at the center of antitumor immunity. Due to the lack of proper costimulation and the abundant immunosuppressive mechanisms, tumor-specific T cells show a lack of persistence and exhausted and dysfunctional phenotypes. Multiple coinhibitory receptors, such as PD-1, CTLA-4, VISTA, TIGIT, TIM-3, and LAG-3, contribute to dysfunctional CTLs and failed antitumor immunity. These coinhibitory receptors are collectively called immune checkpoint receptors (ICRs). Immune checkpoint inhibitors (ICIs) targeting these ICRs have become the cornerstone for cancer immunotherapy as they have established new clinical paradigms for an expanding range of previously untreatable cancers. Given the nonredundant yet convergent molecular pathways mediated by various ICRs, combinatorial immunotherapies are being tested to bring synergistic benefits to patients. In this review, we summarize the mechanisms of several emerging ICRs, including VISTA, TIGIT, TIM-3, and LAG-3, and the preclinical and clinical data supporting combinatorial strategies to improve existing ICI therapies.

Facts and Hopes in Colorectal Cancer Immunotherapy

Although a minority of colorectal cancers exhibit mismatch repair deficiency and associated sensitivity to immune checkpoint inhibitors (ICI), the vast majority of colorectal cancers arise in a tolerogenic microenvironment with mismatch repair proficiency, low tumor-intrinsic immunogenicity, and negligible immunotherapy responsiveness. Treatment strategies to augment tumor immunity with combination ICIs and chemotherapy have broadly failed in mismatch repair-proficient tumors. Similarly, although several small single-arm studies have shown that checkpoint blockade plus radiation or select tyrosine kinase inhibition may show improved outcomes compared with historical controls, this finding has not been clearly validated in randomized trials. An evolving next generation of intelligently engineered checkpoint inhibitors, bispecific T-cell engagers, and emerging CAR-T cell therapies may improve immunorecognition of colorectal tumors. Across these modalities, ongoing translational efforts to better define patient populations and biomarkers associated with immune response, as well as combine biologically sound and mutually amplifying therapies, show promise for a new era of immunotherapy in colorectal cancer.

The CD73 is induced by TGF-β1 triggered by nutrient deprivation and highly expressed in dedifferentiated human melanoma

CD73 is the key enzyme in the generation of extracellular adenosine, a mediator involved in tumor progression, tumor immune escape and resistance to anti-cancer therapeutics. Microenvironmental conditions influence the expression of CD73 in tumor cells. However how CD73 expression and activity is regulated in a stress condition of lower nutrient availability are largely unknown. Our results indicate that serum starvation leads to a marked up-regulation of CD73 expression on A375 melanoma cells in a time-dependent manner. The cell-surface expression of CD73 is associated with an increased release of TGF-β1 by starved cells. Blockade of TGF-β1 receptors or TGFβ/SMAD3 signaling pathway significantly reduce the expression of CD73 induced by starvation. Treatment of cells with rTGF-β1 up-regulates the expression of CD73 in a concentration-dependent manner, confirming the role of this pathway in regulating CD73 in melanoma A375 cells. The increased expression of CD73 is associated with enhanced AMPase activity, which is selectively reduced by inhibitors of CD73 activity, APCP and PSB-12489. Pharmacological blockade of CD73 significantly inhibits invasion of melanoma cells in a transwell system. Furthermore, using multiplex immunofluorescence imaging we found that, within human melanoma metastases, tumor cells at the dedifferentiated stage show the highest CD73 protein expression. In summary, our data provide new insights into the mechanism regulating the expression/activity of CD73 in melanoma cells in a condition of lower availability of nutrients, which is a common feature of the tumor microenvironment. Within human metastatic melanoma tissues elevated protein expression of CD73 is associated with an invasive-like phenotype.

Immune checkpoint therapy for solid tumours: clinical dilemmas and future trends

Immune-checkpoint inhibitors (ICBs), in addition to targeting CTLA-4, PD-1, and PD-L1, novel targeting LAG-3 drugs have also been approved in clinical application. With the widespread use of the drug, we must deeply analyze the dilemma of the agents and seek a breakthrough in the treatment prospect. Over the past decades, these agents have demonstrated dramatic efficacy, especially in patients with melanoma and non-small cell lung cancer (NSCLC). Nonetheless, in the field of a broad concept of solid tumours, non-specific indications, inseparable immune response and side effects, unconfirmed progressive disease, and complex regulatory networks of immune resistance are four barriers that limit its widespread application. Fortunately, the successful clinical trials of novel ICB agents and combination therapies, the advent of the era of oncolytic virus gene editing, and the breakthrough of the technical barriers of mRNA vaccines and nano-delivery systems have made remarkable breakthroughs currently. In this review, we enumerate the mechanisms of each immune checkpoint targets, associations between ICB with tumour mutation burden, key immune regulatory or resistance signalling pathways, the specific clinical evidence of the efficacy of classical targets and new targets among different tumour types and put forward dialectical thoughts on drug safety. Finally, we discuss the importance of accurate triage of ICB based on recent advances in predictive biomarkers and diagnostic testing techniques.

Emerging therapies in cancer metabolism

Metabolic reprogramming in cancer is not only a biological hallmark but also reveals treatment vulnerabilities. Numerous metabolic molecules have shown promise as treatment targets to impede tumor progression in preclinical studies, with some advancing to clinical trials. However, the intricacy and adaptability of metabolic networks hinder the effectiveness of metabolic therapies. This review summarizes the metabolic targets for cancer treatment and provides an overview of the current status of clinical trials targeting cancer metabolism. Additionally, we decipher crucial factors that limit the efficacy of metabolism-based therapies and propose future directions. With advances in integrating multi-omics, single-cell, and spatial technologies, as well as the ability to track metabolic adaptation more precisely and dynamically, clinicians can personalize metabolic therapies for improved cancer treatment.

LSD1: an emerging face in altering the tumor microenvironment and enhancing immune checkpoint therapy

Dysregulation of various cells in the tumor microenvironment (TME) causes immunosuppressive functions and aggressive tumor growth. In combination with immune checkpoint blockade (ICB), epigenetic modification-targeted drugs are emerging as attractive cancer treatments. Lysine-specific demethylase 1 (LSD1) is a protein that modifies histone and non-histone proteins and is known to influence a wide variety of physiological processes. The dysfunction of LSD1 contributes to poor prognosis, poor patient survival, drug resistance, immunosuppression, etc., making it a potential epigenetic target for cancer therapy. This review examines how LSD1 modulates different cell behavior in TME and emphasizes the potential use of LSD1 inhibitors in combination with ICB therapy for future cancer research studies.

Targeting Transcription Factor YY1 for Cancer Treatment: Current Strategies and Future Directions

Cancer represents a significant and persistent global health burden, with its impact underscored by its prevalence and devastating consequences. Whereas numerous oncogenes could contribute to cancer development, a group of transcription factors (TFs) are overactive in the majority of tumors. Targeting these TFs may also combat the downstream oncogenes activated by the TFs, making them attractive potential targets for effective antitumor therapeutic strategy. One such TF is yin yang 1 (YY1), which plays crucial roles in the development and progression of various tumors. In preclinical studies, YY1 inhibition has shown efficacy in inhibiting tumor growth, promoting apoptosis, and sensitizing tumor cells to chemotherapy. Recent studies have also revealed the potential of combining YY1 inhibition with immunotherapy for enhanced antitumor effects. However, clinical translation of YY1-targeted therapy still faces challenges in drug specificity and delivery. This review provides an overview of YY1 biology, its role in tumor development and progression, as well as the strategies explored for YY1-targeted therapy, with a focus on their clinical implications, including those using small molecule inhibitors, RNA interference, and gene editing techniques. Finally, we discuss the challenges and current limitations of targeting YY1 and the need for further research in this area.

Society for Immunotherapy of Cancer (SITC) checkpoint inhibitor resistance definitions: efforts to harmonize terminology and accelerate immuno-oncology drug development

The need for solid clinical definitions of resistance to programmed death 1 or its ligand (PD-(L)1) inhibitors for clinical trial design was identified as a priority by the Society for Immunotherapy of Cancer (SITC). Broad consensus efforts have provided definitions for primary and secondary resistance and resistance after stopping therapy for both single-agent PD-(L)1 inhibitors and associated combinations. Validation of SITC's definitions is critical and requires field-wide data sharing and collaboration. Here, in this commentary, we detail current utility and incorporation of SITC's definitions and discuss the next steps both the society and the field must take to further advance immuno-oncology drug development.

Radiation combined with immune checkpoint inhibitors for unresectable locally advanced non-small cell lung cancer: synergistic mechanisms, current state, challenges, and orientations

Until the advent of immune checkpoint inhibitors (ICIs), definitive radiotherapy (RT) concurrently with chemotherapy was recommended for unresectable, locally advanced non-small cell lung cancer (LA-NSCLC). The trimodality paradigm with consolidation ICIs following definitive concurrent chemoradiotherapy has been the standard of care since the PACIFIC trial. Preclinical evidence has demonstrated the role of RT in the cancer-immune cycle and the synergistic effect of RT combined with ICIs (iRT). However, RT exerts a double-edged effect on immunity and the combination strategy still could be optimized in many areas. In the context of LA-NSCLC, optimized RT modality, choice, timing, and duration of ICIs, care for oncogenic addicted tumors, patient selection, and novel combination strategies require further investigation. Targeting these blind spots, novel approaches are being investigated to cross the borders of PACIFIC. We discussed the development history of iRT and summarized the updated rationale for the synergistic effect. We then summarized the available research data on the efficacy and toxicity of iRT in LA-NSCLC for cross-trial comparisons to eliminate barriers. Progression during and after ICIs consolidation therapy has been regarded as a distinct resistance scenario from primary or secondary resistance to ICIs, the subsequent management of which has also been discussed. Finally, based on unmet needs, we probed into the challenges, strategies, and auspicious orientations to optimize iRT in LA-NSCLC. In this review, we focus on the underlying mechanisms and recent advances of iRT with an emphasis on future challenges and directions that warrant further investigation. Taken together, iRT is a proven and potential strategy in LA-NSCLC, with multiple promising approaches to further improve the efficacy. Video Abstract.

Tackling of Immunorefractory Tumors by Targeting Alternative Immune Checkpoints

Physiologically, well known or traditional immune checkpoints (ICs), such as CTLA-4 and PD-1, are in place to promote tolerance to self-antigens and prevent generation of autoimmunity. In cancer, the ICs are effectively engaged by the tumor cells or stromal ells from the tumor microenvironment through expression of cognate ligands for the ICs present on the cell surface of CD8+ T lymphocytes. The ligation of ICs on CD8+ T lymphocytes triggers inhibitory signaling pathways, leading to quiescence or an exhaustion of CD8+ T lymphocytes. This results in failure of immunotherapy. To overcome this, several FDA-approved therapeutic antibodies are available, but the clinical outcome is quite variable due to the resistance encountered through upregulated expression of alternate ICs such as VISTA, LAG-3, TIGIT and TIM-3. This review focuses on the roles played by the traditional as well as alternate ICs and the contribution of associated signaling pathways in generating such resistance to immunotherapy. Combinatorial targeting of traditional and alternate ICs might be beneficial for immune-refractory tumors.

CAR T cell-based immunotherapy and radiation therapy: potential, promises and risks

CAR T cell-based therapies have revolutionized the treatment of hematological malignancies such as leukemia and lymphoma within the last years. In contrast to the success in hematological cancers, the treatment of solid tumors with CAR T cells is still a major challenge in the field and attempts to overcome these hurdles have not been successful yet. Radiation therapy is used for management of various malignancies for decades and its therapeutic role ranges from local therapy to a priming agent in cancer immunotherapy. Combinations of radiation with immune checkpoint inhibitors have already proven successful in clinical trials. Therefore, a combination of radiation therapy may have the potential to overcome the current limitations of CAR T cell therapy in solid tumor entities. So far, only limited research was conducted in the area of CAR T cells and radiation. In this review we will discuss the potential and risks of such a combination in the treatment of cancer patients.

A Tumor-admixture Model to Interrogate Immune Cell-dependent Tumorigenesis

A rigorous determination of effector contributions of tumor-infiltrating immune cells is critical for identifying targetable molecular mechanisms for the development of novel cancer immunotherapies. A tumor/immune cell-admixture model is an advantageous strategy to study tumor immunology as the fundamental methodology is relatively straightforward, while also being adaptable to scale to address increasingly complex research queries. Ultimately, this method can provide robust experimental information to complement more traditional murine models of tumor immunology. Here, we describe a tumor/macrophage-admixture model using bone marrow-derived macrophages to investigate macrophage-dependent tumorigenesis. Additionally, we provide commentary on potential branch points for optimization with other immune cells, experimental techniques, and cancer types.

Lysine-Specific Demethylase 1 (LSD1)-Mediated Epigenetic Modification of Immunogenicity and Immunomodulatory Effects in Breast Cancers

Tumor evolution to evade immune surveillance is a hallmark of carcinogenesis, and the modulation of tumor immunogenicity has been a challenge to present therapeutic responses in immunotherapies alone for numerous cancers. By altering the cell phenotype and reshaping the tumor microenvironment, epigenetic modifications enable tumor cells to overcome immune surveillance as a mechanism of cancer progression and immunotherapy resistance. Demethylase enzymatic activity of lysine-specific demethylase 1 (LSD1), a histone demethylase first identified in 2004, plays a pivotal role in the vast cellular processes of cancer. While FDA-approved indications for epigenetic therapies are limited to hematological malignancies, it is imperative to understand how epigenetic machinery can be targeted to prime immunotherapy responses in breast cancers. In this review, we discuss the potential roles of epigenetics and demethylating agent LSD1 as a potent new cancer management strategy to combat the current challenges of breast cancers, which have presented modest efficacy to immune checkpoint inhibitors till date. Additionally, we describe the combined use of LSD1-specific inhibitors and immune checkpoint inhibitors in existing breast cancer preclinical and clinical trials that elicits a robust immune response and benefit. Overall, the promising results observed in LSD1-targeting therapies signify the central role of epigenetics as a potential novel strategy to overcome resistance commonly seen in immunotherapies.

Second-line treatment outcomes after progression from first-line chemotherapy plus immunotherapy in patients with advanced non-small cell lung cancer

INTRODUCTION

Chemotherapy plus immunotherapy is the standard of care for patients with metastatic NSCLC. No study has evaluated the outcomes of second-line chemotherapy treatments after progression following first-line chemo-immunotherapy.

METHOD

This multicenter retrospective study evaluated the efficacy of second line (2L) chemotherapies after progression under first-line (1L) chemo-immunotherapy, measured by overall survival (2L-OS) and progression free survival (2L-PFS).

RESULTS

A total of 124 patients were included. The mean age was 63.1 years, 30.6 % of the patients were female, 72.6 % had an adenocarcinoma and 43.5 % had a poor ECOG-performance status prior to 2L initiation. Sixty-four (52.0 %) patients were considered resistant to first line chemo-immunotherapy. (1L-PFS < 6 months). In 2L treatments, 57 (46.0 %) patients received taxane monotherapy, 25 (20.1 %) taxane plus anti-angiogenic, 12 (9.7 %) platinum-based chemotherapy and 30 (24.2 %) other chemotherapy. At a median follow-up of 8.3 months (95 %CI: 7.2-10.2), post initiation of 2L treatment, the median 2L-OS was 8.1 months (95 % CI: 6.4-12.7) and the median 2L-PFS was 2.9 months (95 %CI: 2.4-3.3). Overall, the 2L-objective response and 2L-disease control rates were 16.0 %, and 42.5 %, respectively. Taxane plus anti-angiogenic and platinum rechallenge achieved longest median 2L-OS: not reached (95 %CI: 5.8-NR) and 17.6 months (95 %CI 11.6-NR), respectively (p = 0.05). Patients resistant to the 1L treatment had inferior outcomes (2L-OS 5.1 months, 2L-PFS 2.3 months) compared with 1L responders (2L-OS 12.7 months, 2L-PFS 3.2 months).

CONCLUSION

In this real-life cohort, 2L chemotherapy achieved modest activity following progression under chemo-immunotherapy. 1L-resistant patients remained a refractory population, highlighting a need for new 2L strategies.

Intraindividual Tumor Heterogeneity of Mismatch Repair Status in Metastatic Colorectal Cancer

Heterogeneous mismatch repair (MMR) status in metastatic colorectal cancer (mCRC) may associate with refractoriness to immunotherapy. We aimed here to study the concordance in MMR status between primary and paired metastasis in mCRC. Our study included 84 patients diagnosed with mCRC with primary and matched metastatic cancers. Immunohistochemistry was used to determine the MMR status of primary lesions and matched metastases. Pooled analysis of 913 cases was used to evaluate the prevalence and organ specificity of MMR status heterogeneity. The correlations between MMR pattern heterogeneity and clinical outcomes were analyzed. MMR status heterogeneity between primary and corresponding metastatic sites was exhibited by 10 (11.9%) patients. The prevalence of the heterogeneous MMR phenotype was significantly higher in primary tumors with deficient MMR (dMMR) than with proficient MMR (pMMR), which was verified in the pooled analysis ( P <0.001). Among patients with a dMMR primary tumor, the discrepancy was detected in liver, lung, ovary, peritoneum, and distant lymph node metastases. However, the discrepancy was confined to liver (26/440) or peritoneum (7/112) ( P =0.02) in patients with a pMMR primary tumor. Patients with or without MMR status heterogeneity experienced comparable overall survival ( P =0.452). Heterogeneous MMR patterns generally existed in a subset of patients with mCRC, particularly those with dMMR primary tumors. Testing the metastatic site may be valuable because the discordance of MMR status may potentially affect immune surveillance and immunotherapy.

Differentially Expressed Genes and Signaling Pathways Potentially Involved in Primary Resistance to Chemo-Immunotherapy in Advanced-Stage Gastric Cancer Patients

Recently, the combination of chemotherapy plus nivolumab (chemo-immunotherapy) has become the standard of care for advanced-stage gastric cancer (GC) patients. However, despite its efficacy, up to 40% of patients do not respond to these treatments. Our study sought to identify variations in gene expression associated with primary resistance to chemo-immunotherapy. Diagnostic endoscopic biopsies were retrospectively obtained from advanced GC patients previously categorized as responders (R) or non-responders (NR). Thirty-four tumor biopsies (R: n = 16, NR: n = 18) were analyzed by 3′ massive analysis of cDNA ends (3′MACE). We found >30 differentially expressed genes between R and NRs. Subsequent pathway enrichment analyses demonstrated that angiogenesis and the Wnt-β-catenin signaling pathway were enriched in NRs. Concomitantly, we performed next generation sequencing (NGS) analyses in a subset of four NR patients that confirmed alterations in genes that belonged to the Wnt/β-catenin and the phosphoinositide 3-kinase (PI3K) pathways. We speculate that angiogenesis, the Wnt, and the PI3K pathways might offer actionable targets. We also discuss therapeutic alternatives for chemo-immunotherapy-resistant advanced-stage GC patients.

Cuproptosis key gene FDX1 is a prognostic biomarker and associated with immune infiltration in glioma

Recent studies have found that the protein encoded by the FDX1 gene is involved in mediating Cuproptosis as a regulator of protein lipoylation and related to immune response process of tumors. However, the specific biological function of FDX1 in glioma is currently unclear. To explore the potential function of FDX1, this study explored the correlation between the expression of FDX1 in cancers and survival prognosis by analyzing the public databases of GEPIA and Cbioportal. Immune infiltration was analyzed by the TIMER2.0 database in tumors. The possible biological processes and functions of FDX1-related in glioma were annotated through gene enrichment. Relationship between Cuproptosis and autophagy was explored through gene co-expression studies. Summary and conclusions of this study: (1) FDX1 is highly expressed in gliomas and associated with poor prognosis in low-grade gliomas (LGG). (2) Gene annotation indicates that FDX1 is mainly involved in the tumor protein lipoylation and cell death. (3) FDX1 expression is positively correlated with the infiltration of immune cells. (4) LIPT2 and NNAT, two other genes involved in lipoylation, may be unidentified marker gene for Cuproptosis. And the Cuproptosis genes related to FDX1 were positively correlated with the expression of autophagy marker genes Atg5, Atg12, and BECN-1. This evidence suggests that there may be some interaction between FDX1 mediated Cuproptosis and autophagy. In summary, FDX1 may serve as a potential immunotherapy target and prognostic marker for Glioma.

Tumor Treating Fields (TTFields) Concomitant with Immune Checkpoint Inhibitors Are Therapeutically Effective in Non-Small Cell Lung Cancer (NSCLC) In Vivo Model

Tumor Treating Fields (TTFields) are electric fields that exert physical forces to disrupt cellular processes critical for cancer cell viability and tumor progression. TTFields induce anti-mitotic effects through the disruption of the mitotic spindle and abnormal chromosome segregation, which trigger several forms of cell death, including immunogenic cell death (ICD). The efficacy of TTFields concomitant with anti-programmed death-1 (anti-PD-1) treatment was previously shown in vivo and is currently under clinical investigation. Here, the potential of TTFields concomitant with anti- PD-1/anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4) or anti-programmed death-ligand 1 (anti-PD-L1) immune checkpoint inhibitors (ICI) to improve therapeutic efficacy was examined in lung tumor-bearing mice. Increased circulating levels of high mobility group box 1 protein (HMGB1) and elevated intratumoral levels of phosphorylated eukaryotic translation initiation factor 2α (p-eIF2α) were found in the TTFields-treated mice, indicative of ICD induction. The concomitant application of TTFields and ICI led to a significant decrease in tumor volume as compared to all other groups. In addition, significant increases in the number of tumor-infiltrating immune cells, specifically cytotoxic T-cells, were observed in the TTFields plus anti-PD-1/anti-CTLA-4 or anti-PD-L1 groups. Correspondingly, cytotoxic T-cells isolated from these tumors showed higher levels of IFN-γ production. Collectively, these results suggest that TTFields have an immunoactivating role that may be leveraged for concomitant treatment with ICI to achieve better tumor control by enhancing antitumor immunity.

Multiplexed In Situ Spatial Protein Profiling in the Pursuit of Precision Immuno-Oncology for Patients with Breast Cancer

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of many solid tumors. In breast cancer (BC), immunotherapy is currently approved in combination with chemotherapy, albeit only in triple-negative breast cancer. Unfortunately, most patients only derive limited benefit from ICIs, progressing either upfront or after an initial response. Therapeutics must engage with a heterogeneous network of complex stromal-cancer interactions that can fail at imposing cancer immune control in multiple domains, such as in the genomic, epigenomic, transcriptomic, proteomic, and metabolomic domains. To overcome these types of heterogeneous resistance phenotypes, several combinatorial strategies are underway. Still, they can be predicted to be effective only in the subgroups of patients in which those specific resistance mechanisms are effectively in place. As single biomarker predictive performances are necessarily suboptimal at capturing the complexity of this articulate network, precision immune-oncology calls for multi-omics tumor microenvironment profiling in order to identify unique predictive patterns and to proactively tailor combinatorial treatments. Multiplexed single-cell spatially resolved tissue analysis, through precise epitope colocalization, allows one to infer cellular functional states in view of their spatial organization. In this review, we discuss-through the lens of the cancer-immunity cycle-selected, established, and emerging markers that may be evaluated in multiplexed spatial protein panels to help identify prognostic and predictive patterns in BC.

Common strategies for effective immunotherapy of gastroesophageal cancers using immune checkpoint inhibitors

Gastroesophageal cancers (GECs) are very prevalent around the world and rank as the second cause of all cancer-related deaths in men and women and demonstrate a very poor prognosis. Currently, the treatment options for these malignancies are very limited and the response rates are also very low. Recently, immune checkpoint inhibitors (ICIs) have been proposed for immunotherapy of GECs; although preliminary results obtained from the clinical trials of ICIs in GECs were promising, they have shown to be effective only in a few subsets of patients who had a previous immune response to the tumor. In order to maximize the efficacy of ICIs in GECs, as well as identify the patients who will likely benefit from ICIs, several predictive biomarkers, such as Programmed death-ligand 1 (PD-L1) have been developed and evaluated. Since the single ICI therapies resulted in poor treatment response, several clinical studies began to explore various combinations of one or two ICIs with other anti-cancer treatment approaches, including chemotherapy, radiotherapy, and anti-angiogenesis therapy. These combinations demonstrated a more effective response among the ICIs-responsive patients and even in some instances sensitized the non-responsive individuals. This review is aimed to summarize the efforts made so far for improving the effectiveness of ICIs in the treatment of patients with GECs. Furthermore, multiple aspects of translational medicine such as available biomarkers and interactions between tumor and the immune system, as well as clinical aspects regarding the combination therapies and results of clinical trials will be discussed.

Apatinib: A Novel Antiangiogenic Drug in Monotherapy or Combination Immunotherapy for Digestive System Malignancies

Digestive system malignancies are one of the primary causes of cancer-related death. Meanwhile, angiogenesis has been proved to play an important role in the process of cancer neovascularization. Apatinib, a novel targeted antiangiogenic molecule, could generate highly selective competition in the vascular endothelial growth factor receptor-2, involved in tumor progression and metastasis. It has been implied as a promising cancer treatment agent that can prevent tumor cell proliferation meanwhile inhibit tumor angiogenesis. Furthermore, completed clinical trials demonstrated that apatinib could prolong the progression-free survival and overall survival in advanced gastric cancer and primary liver cancer. Recent studies revealed that apatinib had a synergistic effect with immunotherapy as a second-line and third-line treatment regimen for some other cancers. In this review, we summarize the pharmacological properties of apatinib and the latest clinical application in chemotherapy-refractory patients with advanced digestive system cancer. Based on the comparable survival results, the molecular mechanisms of apatinib are prospective to include the antiangiogenic, apoptosis-inducing, and autophagy-inducing properties in the corresponding signaling pathway. Treatment of apatinib monotherapy or combination immunotherapy remains the optimal option for patients with digestive system malignancies in the future.

Clinical and Biological Significance of a Necroptosis-Related Gene Signature in Glioma

Background

As a novel form of programmed cell death, necroptosis is related to multiple tumor types and their immune microenvironments. However, its association with glioma has not been clarified.

Methods

Necroptosis genes were obtained from the Gene Set Enrichment Analysis (GSEA) database. RNA-seq and clinical data were downloaded from TCGA and CGGA databases. A necroptosis gene signature was constructed based on univariate and multivariate Cox regression analyses. Next, survival analysis, independent prognostic analysis, and nomogram were performed to assess and verify the model. Subsequently, we analyzed the tumor microenvironment (TME) and immune cell infiltration via ESTIMATE and CIBERSORTx algorithms. Finally, the response of glioma patients in the TCGA database to immune checkpoint inhibitor (ICI) therapy was predicted using the Tumor Immune Dysfunction and Exclusion (TIDE) database.

Results

Of the seven prognostic necroptosis genes, RIPK1, RIPK3, FAS, and FADD were used to construct the risk signature that accurately predicts the prognosis of glioma patients. Functional enrichment results suggest that necroptosis is correlated with immune response and angiogenesis. Immune analysis revealed that necroptosis can boost inflammatory activity and attract immunosuppressive cell infiltration to form a chronic inflammatory microenvironment, promoting glioma growth. Additionally, glioma patients in the TCGA cohort with high necroptosis gene expression exhibited a better response to ICI therapy predicted by the TIDE algorithm.

Conclusion

We constructed a necroptosis gene signature, which has the potential for use as a biomarker for predicting glioma patients’ prognosis, revealing the association between necroptosis and the immune microenvironment, and serving as a reference for immune therapy.

Overcoming Resistance to Checkpoint Inhibitors: Natural Killer Cells in Non-Small Cell Lung Cancer

Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatments over the last 10 years, with even increasing indications in many neoplasms. Non-small cell lung cancer (NSCLC) is considered highly immunogenic, and ICIs have found a wide set of applications in this area, in both early and advanced lines of treatment, significantly changing the prognosis of these patients. Unfortunately, not all patients can benefit from the treatment, and resistance to ICIs can develop at any time. In addition to T lymphocytes, which are the major target, a variety of other cells present in the tumor microenvironment (TME) act in a complex cross-talk between tumor, stromal, and immune cells. An imbalance between activating and inhibitory signals can shift TME from an “anti-” to a “pro-tumorigenic” phenotype and vice versa. Natural killer cells (NKs) are able to recognize cancer cells, based on MHC I (self and non-self) and independently from antigen presentation. They represent an important link between innate and adaptive immune responses. Little data are available about the role of pro-inflammatory NKs in NSCLC and how they can influence the response to ICIs. NKs express several ligands of the checkpoint family, such as PD-1, TIGIT, TIM-3, LAG3, CD96, IL1R8, and NKG2A. We and others have shown that TME can also shape NKs, converting them into a pro-tumoral, pro-angiogenic “nurturing” phenotype through “decidualization.” The features of these NKs include expression of CD56, CD9, CD49a, and CXCR3; low CD16; and poor cytotoxicity. During ICI therapy, tumor-infiltrating or associated NKs can respond to the inhibitors or counteract the effect by acting as pro-inflammatory. There is a growing interest in NKs as a promising therapeutic target, as a basis for adoptive therapy and chimeric antigen receptor (CAR)-NK technology. In this review, we analyzed current evidence on NK function in NSCLC, focusing on their possible influence in response to ICI treatment and resistance development, addressing their prognostic and predictive roles and the rationale for exploiting NKs as a tool to overcome resistance in NSCLC, and envisaging a way to repolarize decidual NK (dNK)-like cells in lung cancer.