Mutations in genes encoding DNA repair factors, which facilitate mismatch repair, homologous recombination, or DNA polymerase functions, are known to enhance tumor immunogenicity. Ataxia telangiectasia mutated (ATM) is a central regulator of DNA double-strand break repair and is frequently affected by somatic or germline mutations in various cancer types, including breast, prostate, pancreatic, and lung cancer. However, the consequences of ATM loss on tumor immunogenicity are poorly understood.

We generated isogenic ATM-null models using CRISPR in murine triple-negative breast (4T1) and colorectal (CT26) cancer cell lines. ATM inactivation was confirmed by PCR and western blot. Immune cell infiltrates were assessed by flow cytometry and immunohistochemistry in both murine tumors and human samples from breast and lung cancers (via The Cancer Genome Atlas and institutional cohorts). In vivo, the impact of ATM loss on tumor growth and response to immune checkpoint blockade (anti-programmed cell death protein-1 (PD-1)) was evaluated. Furthermore, we compared the effects of different DNA-damaging agents-including an ATR inhibitor (RP-3500), a PARP inhibitor (olaparib), and the topoisomerase II inhibitor etoposide-on interferon-stimulated gene (ISG) expression and immune modulation.

We find that-in contrast to other DNA repair defects-ATM deficiency (1) fails to encourage immune effector cell infiltration into tumors, and (2) does not enable immune cell recruitment via synthetic lethality strategies in clinical trials, such as with ATR inhibition. Assessing various DNA-damaging agents in Atm null tumors revealed a differential activation of type I interferon (IFN) signaling, with etoposide, a topoisomerase II inhibitor, emerging as the strongest activator of ISG under these conditions. Yet, PD-1-targeted immune checkpoint blockade does not bolster the therapeutic activity of etoposide in Atm-null syngeneic tumor models, nor does it modify the tumor microenvironment, suggesting that type I IFN signaling alone is insufficient to overcome immunosuppression in immunologically cold ATM null neoplasms.

ATM deficiency, while compromising DNA repair and enhancing sensitivity to radiation and ATR inhibition, does not increase tumor antigenicity or immunogenicity. Altogether, our results have important implications for the design of novel combination therapies for ATM null tumors and highlight the importance of antigenicity in the immunological consequences of defective DNA repair.

Identifying host genetic factors modulating immune checkpoint inhibitor (ICI) efficacy is experimentally challenging. Our approach, utilizing the Collaborative Cross mouse genetic resource, fixes the tumor genomic configuration while varying host genetics. We find that response to anti-PD-1 (aPD1) immunotherapy is significantly heritable in four distinct murine tumor models (H2: 0.18-0.40). For the MC38 colorectal carcinoma system, we map four significant ICI response quantitative trait loci (QTLs) with significant epistatic interactions. The differentially expressed genes within these QTLs that define responder genetics are highly enriched for processes involving antigen processing and presentation, allograft rejection, and graft vs. host disease (all p < 1 × 10-10). Functional blockade of two top candidate immune targets, GM-CSF and IL-2RB, completely abrogates the MC38 transcriptional response to aPD1 therapy. Thus, our in vivo experimental platform is a powerful approach for discovery of host genetic factors that establish the tumor immune microenvironment propitious for ICI response.

Pancreatic cancer is a highly aggressive and lethal disease, characterized by a limited response to chemotherapy and overall poor prognosis. Pancreatic cancers with a distinct mismatch repair deficiency, although relatively rare, have been shown to be associated with markedly better outcomes in comparison. Furthermore, whereas pancreatic cancers are generally unresponsive to current immunotherapy, this specific group of tumors has been shown to have a notable susceptibility to immune checkpoint inhibitors.

In this review, we aim to summarize the relevant literature regarding mismatch-repair associated pancreatic cancers, the impacted biological mechanisms, and the resulting vulnerabilities for potential opportunistic immunotherapeutic treatment approaches. We will also review the current clinical studies assessing survival outcomes of mismatch repair deficient pancreatic cancers and ongoing clinical trials in this emerging field.

Patients with dMMR/MSI-H pancreatic cancers harbor a distinct phenotype that has increased immune activation, greater responsiveness to immune checkpoint inhibitor therapy and better overall survival when compared to other pancreatic cancers. Although this molecular subtype makes up a small minority of cases, emerging data suggest immunotherapy may offer benefit to these patients.

Short tandem repeats (STRs) have been reported to influence gene expression across various human tissues. While STR variations are enriched in colorectal, stomach, and endometrial cancers, particularly in microsatellite instable tumors, their functional effects and regulatory mechanisms on gene expression remain poorly understood across these cancer types. Here, we leverage whole-exome sequencing and gene expression data to identify STRs for which repeat lengths are associated with the expression of nearby genes (eSTRs) in colorectal, stomach, and endometrial tumors. While most eSTRs are cancer-specific, shared eSTRs across multiple cancers exhibit consistent effects on gene expression. Notably, coding-region eSTRs identified in all three cancer types show positive correlations with nearby gene expression. We further validate the functional effects of eSTRs by demonstrating associations between somatic eSTR mutations and gene expression changes during the transition from normal to tumor tissues, suggesting their potential roles in tumorigenesis. Combined with DNA methylation data, we perform the first quantitative analysis of the interplay between STR variations and DNA methylation in tumors. We identify eSTRs where repeat lengths are associated with methylation levels of nearby CpG sites (meSTRs) and show that >70% of eSTRs are significantly linked to local DNA methylation. Importantly, the effects of meSTRs on DNA methylation remain consistent across cancer types. Overall, our findings enhance the understanding of how functional STR variations influence gene expression and DNA methylation. Our study highlights shared regulatory mechanisms of STRs across multiple cancers, offering a foundation for future research into their broader implications in tumor biology.

Thyroid hormone receptor-interacting protein 13 (TRIP13) is involved in the regulation of mitosis and is overexpressed in multiple cancers. However, there is no systematic assessment of the role of TRIP13 in the immunotherapy response across human cancers. Therefore, a pan-cancer analysis involving expression, prognosis, immune-related mechanisms, and biomarker values was performed to explore the associations between TRIP13 expression and the immunotherapy response. TRIP13 is highly expressed in various types of cancer, increasing patient outcomes in eight types of cancer. TRIP13 expression was correlated with significant tumor mutation burden and microsatellite instability, and its mutations were linked with poor prognosis in patients with adrenocortical carcinoma. TRIP13 promoted endothelial cell and hematopoietic stem cell infiltration in human cancers. Additionally, TRIP13 mutation significantly increased the infiltration of CD8 + T cells in kidney renal clear cell carcinoma, which might contribute to poor prognosis. Furthermore, three key genes that interact with TRIP13 were identified: CDC20, RAD1, and MAD2L1, which are related to the cell cycle and ultimately promote tumorigenesis and proliferation. The expression of TRIP13 was significantly greater in kidney renal clear cell carcinoma, liver hepatocellular carcinoma, and pancreatic adenocarcinoma cells than in corresponding normal cells according to qPCR. Taken together, these findings indicate that TRIP13 is associated with poor prognosis in eight human cancers and serves as a novel biomarker for predicting immunotherapy efficacy. Our first pan-cancer study contributes to personalized precision medicine in cancer immunotherapy, promoting subsequent clinical management and improving patient prognosis.

Colorectal cancer (CRC) incidence is rising in Nigeria, with majority of patients presenting with advanced disease. Despite promising results of PD-L1 antibody therapy in clinical trials, efficacy data exclusively derives from Caucasian populations, leaving a critical knowledge gap for African populations. This study investigated PD-L1 expression in CRC among blacks, correlating it with clinicopathologic parameters.

The immunohistochemical expression of PD-L1 was evaluated in 96 cases of CRC diagnosed between February 2022 and January 2024, using formalin-fixed paraffin-embedded (FFPE) tissue blocks. Statistical analysis was performed using SPSS version 25. The relationships between the PD-L1 expression and the clinicopathological parameters of CRC patients were determined using the chi-square test and Spearman's rank correlation. p < 0.05 was considered to be statistically significant.

CRC showed a male: female ratio of 1:1.8, most occurred in the seventh decade and 54.17% were right-sided. Adenocarcinoma NOS accounted for 72.5%. The majority (n = 55, 57.3%) of the patients were diagnosed at an advanced stage. PD-L1 expression was observed in 86.46% of cases, significantly correlating with tumour Size (r = 0.263, p = 0.010*), histologic Grade (r = 0.446, p = 0.000*) and tumour Stage (r = 0.367, p = 0.000*).

This study highlighted the high frequency of PD-L1 expression in CRC among black patients, with significant associations to clinicopathologic parameters. The findings suggest the potential benefit of PD-1/PD-L1 targeted therapies and emphasize the need for enhanced early detection and screening in Nigeria.

Immune checkpoint inhibitors (ICIs) have improved outcomes of patients with many different cancers. These antibodies target molecules such as programmed cell death 1 (PD-1) or cytotoxic T lymphocyte associated protein 4 (CTLA-4) which normally function to limit immune activity. Treatment with ICIs reactivates T cells to destroy tumor cells in a highly specific manner, which in some patients, results in dramatic remissions and durable disease control. Over the last decade, much effort has been directed at characterizing factors that drive efficacy and resistance to ICI therapy. Food and Drug Administration (FDA)-approved biomarkers for ICI therapy have facilitated more judicious treatment of cancer patients and transformed the field of precision oncology. Yet, adaptive immunity against cancers is complex, and newer data have revealed the potential utility of other biomarkers. In this review, we discuss the utility of currently approved biomarkers and highlight how emerging biomarkers can further improve the identification of patients who benefit from ICIs.

Cancer treatment has long been hindered by the complexity of the tumor microenvironment (TME) and the mechanisms that tumors employ to evade immune detection. Recently, the combination of immune checkpoint inhibitors (ICIs) and anti-angiogenic therapies has emerged as a promising approach to improve cancer treatment outcomes. This review delves into the role of immunostimulatory molecules and ICIs in enhancing anti-tumor immunity, while also discussing the therapeutic potential of anti-angiogenic strategies in cancer. In particular, we highlight the critical role of endoplasmic reticulum (ER) stress in angiogenesis. Moreover, we explore the potential of macrophage reprogramming to bolster anti-tumor immunity, with a focus on restoring macrophage phagocytic function, modulating hypoxic tumor environments, and targeting cytokines and chemokines that shape immune responses. By examining the underlying mechanisms of combining ICIs with anti-angiogenic therapies, we also review recent clinical trials and discuss the potential of biomarkers to guide and predict treatment efficacy.

Deficiency in DNA mismatch repair (dMMR) is a common pathway of carcinogenesis across different tumour types and confers a characteristic microsatellite instability-high (MSI-H) molecular phenotype. The prevalence of the MSI-H/dMMR phenotype is highest in endometrial and colorectal cancers, and this phenotype is associated with a distinct tumour biology, prognosis and responsiveness to various anticancer treatments. In a minority of patients, MSI-H/dMMR cancers result from an inherited pathogenic variant in the context of Lynch syndrome, which has important implications for familial genetic screening. Whether these hereditary cancers have a different biology and clinical behaviour to their sporadic counterparts remains uncertain. Interest in this tumour molecular subtype has increased following the discovery of the high sensitivity of metastatic MSI-H/dMMR cancers to immune-checkpoint inhibitors (ICIs) in a histology-agnostic manner, which reflects the genomic hypermutation resulting from dMMR that renders these tumours highly immunogenic and immune infiltrated. This vulnerability is now also being exploited in early stage disease settings. Despite this common biological foundation, different MSI-H/dMMR cancers have histotype-specific features that correspond to their particular cell or tissue of origin, which might be associated with differences in prognosis and sensitivity to ICIs. In this Review, we provide an overview of the epidemiology, biology, pathogenesis, clinical diagnosis and treatment of MSI-H/dMMR tumours as a histology-agnostic cancer phenomenon. We also highlight peculiarities associated with specific pathogenetic alterations and histologies of MSI-H/dMMR tumours.

Mismatch repair deficiency (dMMR) cancers are highly sensitive to immunotherapy, but only account for a small fraction of cancer patients. How to increase immunotherapy efficacy on MMR-proficient (pMMR) cancer is still a major challenge. This study demonstrates that pyrithione zinc (PYZ), an FDA-approved drug, can enhance tumor immunogenicity via altering MMR and activating STING signaling. Mechanistically, PYZ elevates levels of ROS, leading to the upregulation of HIF-1α and DNA damage, while also inhibiting the expression of DNA mismatch repair proteins MSH2 and MSH6, together promoting DNA damage accumulation. Therefore, the administration of PYZ results in the accumulation of DNA damage, leading to the activation of STING signaling, which enhances tumor immunogenicity. Knockout of Sting diminishes the activation of IFN-I signaling induced by PYZ and reduces tumor immunogenicity. Furthermore, in vivo administration of PYZ promotes the infiltration of CD8+ T cells into the tumor and inhibits tumor growth, an effect that is attenuated in Nude mice or mice with CD8+ T cell depletion or deficiency of Ifnar. Overall, our findings showed that pyrithione zinc could trigger tumor immunogenicity by downregulating MMR machinery and activating STING pathway in tumor cells, and provide a translational approach to improve immunotherapy on pMMR cancer.

The tumor microenvironment (TME) milieu directs a plethora of tumor-modulating functions. Recent years have seen pivotal breakthroughs in our understanding of the TME's role in tumor initiation and progression, with tangible clinical applications. Individual components of the TME exert their function predominantly by cell-cell crosstalk, both in the form of physical interaction and secreted factors. Notably, different spatial niches represent exclusive signaling hubs in the TME, propagating pro- or antitumoral functions. The exploration of these interactions has been vastly facilitated by novel molecular technologies, each of which provides a different perspective on this intricate intercellular communication network. Together, these complementary methods paint a detailed, high-resolution map of the TME's interaction landscape. In this viewpoint, we explore how cellular interactions can unlock a new level of understanding of TME complexity, and discuss the promises and challenges of characterizing tumors based on their cellular interaction footprint.

Immune checkpoint blockade therapy using programmed cell death 1 (PD1) or programmed death ligand 1 (PD-L1) has made significant progress in the treatment of advanced cancers, with some patients achieving long-term remission without clinical recurrence. However, only a minority of colon cancer patients respond to the therapy. Here, we report a protease-cleavable anti-PD-L1 antibody liposome, eLipo anti-PD-L1, for enhancing colon cancer therapy. In vivo, eLipo anti-PD-L1 is cleaved by legumain at colon cancer site into pegylated anti-PD-L1 and cancer-homing doxorubicin liposome. Functional assessments show cancer-targeting, legumain-responding, tumor-penetrating, and immune-activating effects, as well as efficacy in treating colon cancer-bearing mice in vivo. Further mechanistic analysis implicates genes related to T cell differentiation and T cell receptor signaling as potential molecular mediators. Lastly, human colorectal cancer tissue evaluations verify expressions of PD-L1 and legumain, hinting a potential translatability. Our study thus suggests that eLipo anti-PD-L1 may be a feasible vector for co-delivery of immunochemotherapy for colon cancer.

The mismatch repair (MMR) pathway is known as a tumor suppressive pathway and genes involved in MMR are commonly mutated in hereditary colorectal or other cancer types. However, the function of MMR genes/proteins in breast cancer progression and metastasis are largely undefined. We found that MSH2, but not MLH1, is highly enriched in basal-like breast cancer (BLBC) and that its protein expression is inversely correlated with overall survival time (OS). MSH2 expression is frequently elevated due to genomic amplification or gain-of-expression in BLBC, which results in increased MSH2 protein to pair with MSH6 (collectively referred to as MutSα). Genetic deletion of MSH2 or MLH1 results in a contrasting phenotype in metastasis, with MSH2 -deletion leading to reduced metastasis and MLH1 -deletion to enhanced liver or lung metastasis. Mechanistically, MSH2 - but not MLH1 - binds to the promoter region of interferon α receptor 1 ( IFNAR1 ) and suppresses its expression in BLBC. Deletion of MSH2 initiates a chain of immune reactions via the upregulation of IFNAR1 expression and the activation of type 1 interferon signaling, which explains a highly immune active tumor microenvironment in tumors with MSH2-deficiency. Our study supports the contrasting functions of MSH2 and MLH1 in BLBC progression and metastasis due to the differential regulation of IFNAR1 expression, which challenges the paradigm of the MMR pathway as a universal tumor suppressive mechanism.

MCAM, alternatively referred to as CD146, is an integral membrane glycoprotein belonging to the immunoglobulin superfamily. However, its importance in the tumorigenesis of colorectal cancer is still partially understood. Therefore, this study was designed to investigate the significance of MCAM in colorectal cancer.

MCAM expression was analyzed by TCGA and GEO databases. qRT-PCR and IHC analysis were conducted to validate MCAM expression in patient tissues. The tumor-inhibiting ability of MCAM was further assessed by CCK-8 assay, colony formation assay, and wound-healing assay. qRT-PCR and WB analysis were conducted to evaluate the expression of EMT markers and MMP2/9. qRT-PCR analysis was utilized to detect the polarization status of macrophages. Kaplan-Meier curve, univariate, and multivariate cox analyses were employed to verify the ability of MCAM in prognosis prediction. TIDE scores were used to assess the impact of MCAM on immunotherapy.

The expression of MCAM was significantly downregulated in CRC, and low MCAM expression revealed poor prognosis in CRC patients. Moreover, MCAM overexpression inhibited the proliferation, migration, and invasive ability of CRC cells. Additionally, MCAM overexpression suppressed N-cadherin and MMP2/9 expression. Furthermore, MCAM impacted M1 macrophage polarization. MCAM is an independent predictor of CRC patient prognosis through Cox regression analysis. Lastly, TIDE score analysis indicated that elevated expression of MCAM increased immunotherapy efficacy.

The findings of this research suggest that MCAM impacts M1 macrophage polarization and enhances immunotherapy efficacy, underscoring its potential as a therapeutic target for colorectal cancer.

The role of cancer-associated fibroblasts (CAFs) in modulating the tumor microenvironment (TME) is gaining attention, yet their impact on prognosis and therapeutic response in colon cancer remains unclear. Here, we identified genes associated with CAF infiltration via weighted gene co-expression network analysis (WGCNA) utilizing data from The Cancer Genome Atlas (TCGA) and GSE39582 cohorts. Univariate Cox regression and least absolute shrinkage and selection operator (LASSO) regression analyses were used to construct CAF molecular signatures (CAFscore). Patients were categorized into high and low CAFscore groups to analyze clinicopathological traits, somatic mutations, immune evasion, and treatment responses. In this study, a total of 244 genes were correlated with CAF infiltration, with 11 linked to overall survival. Notably, FSTL3, CRIP2, and SLC2A3 were selected for the CAFscore. A higher CAFscore was associated with poorer prognoses, increased malignancy, and therapeutic resistance, particularly among patients with high tumor mutation burden and microsatellite instability. Furthermore, elevated FSTL3 expression was associated with reduced CD8+ T cell infiltration, indicating a suppressive TME. Mechanistically, CAFs may promote immune evasion via NAMPT ligand-receptor interactions based on single-cell RNA sequencing data. Thus, the CAFscore is crucial for personalizing treatment strategies and identifying patients who require more aggressive management.

Mismatch repair-deficient (dMMR) tumors have demonstrated favorable responses to immune checkpoint inhibition targeting PD-1. However, more in-depth identification of predictors of response could further refine patient selection for immunotherapy treatment.

We undertook integrated evaluation performed on samples collected from 28 of 42 patients enrolled on the NCI-Molecular Analysis for Therapy Choice arm Z1D trial that evaluated PD-1 inhibition treatment with nivolumab in patients with noncolorectal dMMR tumors. Genomic analyses were performed using next-generation sequencing (NGS), whole-exome sequencing, and RNA sequencing and supplemented by multiplex immunofluorescence performed on tissue samples.

In this dMMR population, more extensive alterations of microsatellites as assessed by measures of NGS were associated with clinical benefit and tumor mutational burden. RNA sequencing further revealed associations between clinical benefit and immune infiltration index. Gene sets enriched in patients with clinical benefit included IFN signaling, antigen processing, and PI3K-AKT-mTOR signaling, whereas hedgehog signaling was found to be enriched in subjects lacking clinical benefit.

These genomic data highlight the importance of immune infiltration and antigen presentation in dMMR tumors that respond to immune checkpoint blockade. In addition, they suggest that, even within a dMMR population, NGS-based measures of microsatellite instability could serve as biomarkers of immunotherapy response.

Mismatch repair deficiency (MMRd), either due to inherited or somatic mutation, is prevalent in colorectal cancer (CRC) and other cancers. While anti-PD-1 therapy is utilized in both local and advanced disease, up to 50% of MMRd CRC fail to respond. Using animal and human models of MMRd, we determined that interactions between MHC+ C1Q+ CXCL9+ macrophages and TCF+ BHLHE40+ PRF1+ T cell subsets are associated with control of MMRd tumor growth, during anti-PD-1 treatment. In contrast, resistance is associated with upregulation of TIM3, LAG3, TIGIT, and PD-1 expression on T cells, and infiltration of the tumor with immunosuppressive TREM2+ macrophages and monocytes. By combining anti-PD-1 with anti-LAG3/CTLA4/TREM2, up to 100% tumor eradication was achieved in MMRd CRC and remarkably, in >70% in MMRp CRC. This study identifies key T cell and macrophage subsets mediating the efficacy of immunotherapy in overcoming immune escape in both MMRd and MMRp CRC settings.

Anti-PD-1 therapy leads to the accumulation and colocalization of MHCI/II+ C1Q+ CXCL9+ macrophages and DCs with TCF+ CCL5+ T cells that have high TCR diversity.Resistance to anti-PD-1 therapy involves multiple T cell checkpoints, TREM2+ macrophages, IL1B+ TREM1+ monocytes and neutrophils, and IFITM+ tumor cells.Simultaneous blockade of PD-1, LAG3, CTLA-4 and TREM2 dramatically prevents progression of both MMRd and MMRp tumors.Combination therapy completely eliminates tumors by leveraging MHC+ macrophage, CD4+ and CD8+ T cell interactions, facilitating durable anti-tumor effects.

Despite exciting developments in cancer immunotherapy, its broad application is limited by the paucity of targetable antigens on the tumor cell surface. As an intrinsic cellular pathway, nonsense-mediated decay (NMD) conceals neoantigens through the destruction of the RNA products from genes harboring truncating mutations. We developed and conducted a high-throughput screen, based on the ratiometric analysis of transcripts, to identify critical mediators of NMD in human cells. This screen implicated disruption of kinase SMG1's phosphorylation of UPF1 as a potential disruptor of NMD. This led us to design a novel SMG1 inhibitor, KVS0001, that elevates the expression of transcripts and proteins resulting from human and murine truncating mutations in vitro and murine cells in vivo. Most importantly, KVS0001 concomitantly increased the presentation of immune-targetable human leukocyte antigens (HLA) class I-associated peptides from NMD-downregulated proteins on the surface of human cancer cells. KVS0001 provides new opportunities for studying NMD and the diseases in which NMD plays a role, including cancer and inherited diseases.

Resistance to immune checkpoint inhibitors (ICI) is common, even in tumors with T-cell infiltration. We thus investigated consequences of ICI-induced T-cell infiltration in the microenvironment of resistant tumors. T cells and neutrophil numbers increased in ICI-resistant tumors following treatment, in contrast to ICI-responsive tumors. Resistant tumors were distinguished by high expression of IL1 receptor 1, enabling a synergistic response to IL1 and TNFα to induce G-CSF, CXCL1, and CXCL2 via NF-κB signaling, supporting immunosuppressive neutrophil accumulation in tumor. Perturbation of this inflammatory resistance circuit sensitized tumors to ICIs. Paradoxically, T cells drove this resistance circuit via TNFα both in vitro and in vivo. Evidence of this inflammatory resistance circuit and its impact also translated to human cancers. These data support a mechanism of ICI resistance, wherein treatment-induced T-cell activity can drive resistance in tumors responsive to IL1 and TNFα, with important therapeutic implications.

Glioblastoma (GBM), the most common and aggressive primary central nervous system (CNS) tumor in adults, continues to have a dismal prognosis. Across hundreds of clinical trials, few novel approaches have translated to clinical practice while survival has improved by only a few months over the past three decades. Randomized controlled trials of immune checkpoint inhibitors (ICIs), which have seen impressive success for advanced or metastatic extracranial solid tumors, have so far failed to demonstrate a clinical benefit for patients with GBM. This has been secondary to GBM heterogeneity, the unique immunosuppressive CNS microenvironment, immune-evasive strategies by cancer cells, and the rapid evolution of tumor on therapy. This review aims to summarize findings from major clinical trials of ICIs for GBM, review historic failures, and describe currently promising avenues of investigation. We explore the biological mechanisms driving ICI responses, focusing on the role of the tumor microenvironment, immune evasion, and molecular biomarkers. Beyond conventional monotherapy approaches targeting PD-1, PD-L1, CTLA-4, we describe emerging approaches for GBM, such as dual-agent ICIs, and combination of ICIs with oncolytic virotherapy, antigenic peptide vaccines, chimeric antigenic receptor (CAR) T-cell therapy, along with nanoparticle-based delivery systems to enhance ICI efficacy. We highlight potential strategies for improving patient selection and treatment personalization, along with real-time, longitudinal monitoring of therapeutic responses through advanced imaging and liquid biopsy techniques. Integrated radiomics, tissue, and plasma-based analyses, may potentially uncover immunotherapeutic response signatures, enabling early, adaptive therapeutic adjustments. By specifically targeting current therapeutic challenges, outcomes for GBM patients may potentially be improved.

The impact of chirality on immune response has attracted great interest in cancer vaccine research recently. However, the study of chiral synthetic polypeptide hydrogels as cancer vaccines as well as of the impact of biomaterials themselves for antitumor immunotherapy has rarely been reported. Here, we show the key role of residue chirality of polypeptide hydrogels in antitumor immunity and local immune microenvironment regulation. Compared to poly(γ-ethyl-L-glutamate)-based hydrogels (L-Gel), poly(γ-ethyl-D-glutamate)-based hydrogels (D-Gel) induces enhanced level of immune cell infiltration. However, D-Gel causes higher levels of suppressive markers on antigen-presenting cells and even induces stronger T cell exhaustion than L-Gel. Finally, D-Gel establishes a local chronic inflammatory and immunosuppressive microenvironment and shows insufficient anti-tumor effects. Conversely, the milder host immune responses induced by L-Gel leads to more effective tumor inhibition. This study provides insights on the role of residue chirality in the regulation of local immune microenvironment and affecting antitumor immune response.

Cancer immunotherapy, alongside surgery, radiation therapy, and chemotherapy, has emerged as a key treatment modality. Immune checkpoint inhibitors (ICIs) represent a promising immunotherapy that plays a critical role in the management of various solid tumors. However, the limited efficacy of ICI monotherapy and the development of primary or secondary resistance to combination therapy remain a challenge. Consequently, identifying molecular markers for predicting ICI efficacy has become an area of active clinical research. Notably, the correlation between DNA damage repair (DDR) mechanisms and the effectiveness of ICI treatment has been established. This review outlines the two primary pathways of DDR, namely, the homologous recombination repair pathway and the mismatch repair pathway. The relationship between these key genes and ICIs has been discussed and the potential of these genes as molecular markers for predicting ICI efficacy summarized.

Despite the established use of immune checkpoint inhibitors (ICIs) to treat non-small cell lung cancer (NSCLC), only a subset of patients benefit from treatment and ∼50% of patients whose tumors respond eventually develop acquired resistance (AR). To identify novel drivers of AR, we generated murine Msh2 knock-out (KO) lung tumors that initially responded but eventually developed AR to anti-PD-1, alone or in combination with anti-CTLA-4. Resistant tumors harbored decreased infiltrating T cells and reduced cancer cell-intrinsic MHC-I and MHC-II levels, yet remained responsive to IFNγ. Resistant tumors contained extensive regions of hypoxia, and a hypoxia signature derived from single-cell transcriptional profiling of resistant cancer cells was associated with decreased progression-free survival in a cohort of NSCLC patients treated with anti-PD-1/PD-L1 therapy. Targeting hypoxic tumor regions using a hypoxia-activated pro-drug delayed AR to ICIs in murine Msh2 KO tumors. Thus, this work provides a rationale for targeting tumor metabolic features, such as hypoxia, in combination with immune checkpoint inhibition.

Digestive system neoplasms are highly heterogeneous and exhibit complex resistance mechanisms that render anti-programmed cell death protein (PD) therapies poorly effective. The tumor microenvironment (TME) plays a pivotal role in tumor development, apart from supplying energy for tumor proliferation and impeding the body's anti-tumor immune response, the TME actively facilitates tumor progression and immune escape via diverse pathways, which include the modulation of heritable gene expression alterations and the intricate interplay with the gut microbiota. In this review, we aim to elucidate the mechanisms underlying drug resistance in digestive tumors, focusing on immune-mediated resistance, microbial crosstalk, metabolism, and epigenetics. We will highlight the unique characteristics of each digestive tumor and emphasize the significance of the tumor immune microenvironment (TIME). Furthermore, we will discuss the current therapeutic strategies that hold promise for combination with cancer immune normalization therapies. This review aims to provide a thorough understanding of the resistance mechanisms in digestive tumors and offer insights into potential therapeutic interventions.

Immunogenic cell death (ICD) has been associated with enhanced anti-tumor immunotherapy by stimulating adaptive immune responses and remodeling the immune microenvironment in tumors. Nevertheless, the role of ICD-related genes in ovarian cancer (OC) and tumor microenvironment remains unexplored.

In this study, high-throughput transcriptomic data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases as training and validation sets separately were obtained and proceeded to explore ICD-related clusters, and an ICD-related risk signature was conducted based on the least absolute shrinkage and selection operator (LASSO) Cox regression model by iteration. Multiple tools including CIBERSORT, ESTIMATE, GSEA, TIDE, and immunohistochemistry were further applied to illustrate the biological roles of ICD-related genes as well as the prognostic capacity of ICD risk signature in OC.

Two ICD-related subtypes were identified, with the ICD-high subtype showing more intense immune cell infiltration and higher activities of immune response signaling, along with a favorable prognosis. Additionally, four candidate ICD genes (IFNG, NLRP3, FOXP3, and IL1B) were determined to potentially impact OC prognosis, with an upregulated expression of NLRP3 in OC and metastatic omental tissues. A prognostic model based on these genes was established, which could predict overall survival (OS) and response to immunotherapy for OC patients, with lower-risk patients benefiting more from immunotherapy.

Our research conducted a prognostic and prediction of immunotherapy response model based on ICD genes, which could be instrumental in assessing prognosis and assigning immunotherapeutic strategies for OC patients. NLRP3 is a promising target for prognosis in OC.

This study developed and validated a novel deep learning radiomic biomarker to estimate response to immune checkpoint inhibitor (ICI) therapy in advanced non-small cell lung cancer (NSCLC) using real-world data (RWD) and clinical trial data.

Retrospective RWD of 1,829 patients with advanced NSCLC treated with PD-(L)1 ICIs were collected from 10 academic and community institutions in the United States and Europe. The RWD included data sets for discovery (Data Set A-Discovery, n = 1,173) and independent test (Data Set B, n = 458). A radiomic pipeline, containing a deep learning feature extractor and a survival model, generated the computed tomography (CT) response score (CTRS) applied to the pretreatment routine CT/positron emission tomography (PET)-CT scan. An enhanced CTRS (eCTRS) also incorporated age, sex, treatment line, and lesion annotations. Performance was evaluated against progression-free survival (PFS) and overall survival (OS). Biomarker generalizability was further evaluated using a secondary analysis of a prospective clinical trial (ClinicalTrials.gov identifier: NCT02573259) evaluating the PD-1 inhibitor sasanlimab in second or later line of treatment (Data Set C, n = 54).

In RWD Test Data Set B, the CTRS identified patients with a high probability of response to ICI with a PFS hazard ratio (HR) of 0.46 (95% CI, 0.26 to 0.82) and an OS HR of 0.50 (95% CI, 0.28 to 0.92) in the first-line ICI monotherapy cohort, after adjustment for baseline covariates including the PD-L1 tumor proportion score. In Clinical Trial Data Set C, the CTRS demonstrated an adjusted PFS HR of 1.03 (95% CI, 0.43 to 2.47) and an OS HR of 0.33 (95% CI, 0.14 to 0.91). The CTRS and eCTRS outperformed traditional imaging biomarkers of lesion size in PFS and OS for RWD Test Data Set B and in OS for the Clinical Trial Data Set.

The study developed and validated a deep learning radiomic biomarker using pretreatment routine CT/PET-CT scans to identify ICI benefit in advanced NSCLC.

Currently, PD-(L)1 blockade-based neoadjuvant treatment has shown promising outcomes in patients with potentially resectable gastric cancer. In this real-world study, we aimed to retrospectively observe the efficacy including tumor response and event-free survival (EFS), and safety of PD-(L)1 blockade-based neoadjuvant treatment versus chemotherapy alone in potentially resectable gastric cancer patients with microsatellite instability-high (MSI-H) or mismatch-repair deficient (dMMR) status.

We retrospectively collected the clinical data of patients with potentially resectable gastric cancer and MSI-H/dMMR status who received neoadjuvant treatment followed by D2 gastrectomy at the Affiliated Hospital of Qingdao University from January 2019 to June 2023. The outcomes of interest mainly included overall complete response (CR) rates, radiographical and pathological tumor response, treatment-related adverse events (TRAEs), and EFS.

In total, 30 patients were included in the analysis; 23 patients received neoadjuvant PD-(L)1 blockade plus chemotherapy or PD-(L)1 blockade monotherapy, and seven patients received neoadjuvant chemotherapy. In the PD-(L)1 blockade-based treatment group, 7 of 23 patients (30.4%, 95% CI 0.141-0.530) achieved pathological CR (pCR), while three patients with radiographical CR did not undergo surgery. In contrast, 1 of 7 (14.3%) patients in the neoadjuvant chemotherapy group achieved pCR. The overall CR rate was 43.5% (10 of 23, 95% CI 0.239-0.651) in the PD-(L)1 blockade-based treatment group and 14.3% (1 of 7, 95% CI 0.026-0.513) in the chemotherapy group. The neoadjuvant PD-(L)1 blockade-based treatment regimen was mild and well tolerated. By the latest follow-up, median EFS time was not reached in both cohorts.

In potentially resectable gastric cancer patients with MSI-H/dMMR status, PD-(L)1 blockade-based neoadjuvant treatment regimen provided promising clinical benefits and was well tolerated.

With the increasing number of indications for immune checkpoint inhibitors in early and advanced cancers, the prospect of a tumor-agnostic biomarker to prioritize patients is compelling. Tumor mutation burden (TMB) is a widely endorsed biomarker that quantifies nonsynonymous mutations within tumor DNA, essential for neoantigen production, which, in turn, correlates with the immune response and guides decision-making. However, the general clinical application of TMB-relying on simple mutational counts targeted at a single endpoint-does not adequately capture the complex clonal structure of tumors nor the multifaceted nature of prognostic indicators. This recognition has spurred the exploration of sophisticated high-dimensional regression techniques. Unfortunately, the limited cohort sizes in immunotherapy trials have hindered the full potential of these advanced methods. Our approach considers patient subgroups as related yet distinct entities, enabling precise tailoring and refinement to address subgroup-specific dynamics. Given the deficiencies and the constraints, we introduce a TMB heterogeneity-optimized regression (THOR). This innovative model enhances the predictive capabilities of TMB by integrating tumor clonality and a diverse spectrum of clinical endpoints, further augmented by fusion techniques across subgroups to facilitate robust data sharing and interpretation. Our simulations validate THOR's superiority in parameter estimation for statistical inference. Clinically, we assess the utility of THOR in a structured cohort of 238 cancer patients undergoing immunotherapy, supplemented by 2212 patients across 19 subgroups from public datasets. The forecast of the responses and comparison of survival hazards demonstrate that THOR significantly enhances patient stratification and prognostic predictions by incorporating complex immunogenetic biology and subgroup-specific dynamics.

Microsatellite instability (MSI) and mismatch repair (MMR) detection is valuable in assessing prognosis and treatment options. However, the conventional detection methods such as immunohistochemistry (IHC) are limited by not fully consistent results as well as a long turnaround time. TrueMark™ MSI Assay is a novel solution for MSI analysis, but lack of research support in the Chinese colorectal cancer (CRC) patients.

60 dMMR and 60 pMMR CRC samples identified by IHC were collected and their MSI status were detected using TrueMark™ MSI assay with an expanded panel of 13 markers. The overall performance and diagnostic concordance between TrueMark™ MSI test and MMR IHC analysis were assessed and analyzed.

According to the TrueMark™ test, 55 out of the 120 (45.8 %) CRCs were identified as MSI-high (MSI-H) with an instability at ≥ 4/13 markers. Compared with the MMR IHC analysis, an overall percent agreement of 94.2 % and a Kappa of 0.883 were achieved. For the seven inconsistent samples, tumor mutation burden analysis was performed and the results supported the diagnosis by TrueMark™ test. To confirm the robustness of the above findings, a validation was performed in an independent cohort comprising 51 consecutive CRCs. Furthermore, an optimized panel composed of NR-21, NR-24, NR-27, ABI-16, ABI-17 and ABI-20B was developed by multivariate logistic regression model, and showed 100 % agreement with the 13-marker panel for MSI detection in both the derivation and validation sets.

TrueMark™ MSI provides a fast, reliable and highly automated solution to MSI detection in Chinese CRC patients, and the new 6-marker panel we established shows promise deserving further evaluation.

Neoantigen immunoediting drives immune checkpoint blockade efficacy, yet the molecular features of neoantigens and how neoantigen immunogenicity shapes treatment response remain poorly understood. To address these questions, 80 patients with non-small cell lung cancer were enrolled in the biomarker cohort of CheckMate 153 (CA209-153), which collected radiographic guided biopsy samples before treatment and during treatment with nivolumab. Early loss of mutations and neoantigens during therapy are both associated with clinical benefit. We examined 1,453 candidate neoantigens, including many of which that had reduced cancer cell fraction after treatment with nivolumab, and identified 196 neopeptides that were recognized by T cells. Mapping these neoantigens to clonal dynamics, evolutionary trajectories and clinical response revealed a strong selection against immunogenic neoantigen-harboring clones. We identified position-specific amino acid and physiochemical features related to immunogenicity and developed an immunogenicity score. Nivolumab-induced microenvironmental evolution in non-small cell lung cancer shared some similarities with melanoma, yet critical differences were apparent. This study provides unprecedented molecular portraits of neoantigen landscapes underlying nivolumab's mechanism of action.

Colorectal cancer (CRC) remains one of the major causes of cancer death worldwide. Chemotherapy continues to serve as the primary treatment modality, while immunotherapy is largely ineffective for the majority of CRC patients. Seminal discoveries have emphasized that modifying DNA damage response (DDR) mechanisms confers both cell-autonomous and immune-related vulnerabilities across various cancers. In CRC, approximately 15% of tumours exhibit alterations in the mismatch repair (MMR) machinery, resulting in a high number of neoantigens and the activation of the type I interferon response. These factors, in conjunction with immune checkpoint blockades, collectively stimulate anticancer immunity. Furthermore, although less frequently, somatic alterations in the homologous recombination (HR) pathway are observed in CRC; these defects lead to genome instability and telomere alterations, supporting the use of poly (ADP-ribose) polymerase (PARP) inhibitors in HR-deficient CRC patients. Additionally, other DDR inhibitors, such as Ataxia Telangiectasia and Rad3-related protein (ATR) inhibitors, have shown some efficacy both in preclinical models and in the clinical setting, irrespective of MMR proficiency. The aim of this review is to elucidate how preexisting or induced vulnerabilities in DNA repair pathways represent an opportunity to increase tumour sensitivity to immune-based therapies in CRC.