Immunotherapy in colorectal cancer: rationale, challenges and potential

Fusobacterium nucleatum upregulates the immune inhibitory receptor PD-L1 in colorectal cancer cells via the activation of ALPK1

Fusobacterium nucleatum is a Gram-negative oncobacterium that is associated with colorectal cancer. The molecular mechanisms utilized by F. nucleatum to promote colorectal tumor development have largely focused on adhesin-mediated binding to the tumor tissue and on the pro-inflammatory capacity of F. nucleatum. However, the exact manner in which F. nucleatum promotes inflammation in the tumor microenvironment and subsequent tumor promotion remains underexplored. Here, we show that both living F. nucleatum and sterile F. nucleatum-conditioned medium promote CXCL8 release from the intestinal adenocarcinoma HT-29 cell line. We determined that the observed pro-inflammatory effect was ALPK1-dependent in both HEK293 and HT-29 cells and that the released F. nucleatum molecule had characteristics that match those of the pro-inflammatory ALPK1 ligand ADP-heptose or related heptose phosphates. In addition, we determined that not only F. nucleatum promoted an ALPK1-dependent pro-inflammatory environment but also other Fusobacterium species such as F. varium, F. necrophorum and F. gonidiaformans generated similar effects, indicating that ADP-heptose or related heptose phosphate secretion is a conserved feature of the Fusobacterium genus. By performing transcriptional analysis of ADP-heptose stimulated HT-29 cells, we found several inflammatory and cancer-related pathways to be differentially regulated, including DNA mismatch repair genes and the immune inhibitory receptor PD-L1. Finally, we show that stimulation of HT-29 cells with F. nucleatum resulted in an ALPK1-dependent upregulation of PD-L1. These results aid in our understanding of the mechanisms by which F. nucleatum can affect tumor development and therapy and pave the way for future therapeutic approaches.

A targeted MAVS fusion protein for controlled innate immune activation and antitumor therapy

Targeted therapies leveraging the innate immune system are emerging as promising cancer treatments. The mitochondrial antiviral signaling protein (MAVS) plays a crucial role in initiating innate immune responses, but its clinical use is limited by the risk of uncontrolled activation and systemic toxicity. To address this, we developed a novel therapeutic agent, the truncated interferon activation switch (TRIAS), combining MAVS truncates with a tumor antigen-targeting single-chain variable fragment (scFv). This design ensures antigen-dependent, controlled activation. Lentiviral delivery of TRIAS induced significant antitumor responses, including complete tumor regression in some cases. Flow cytometry (FCM) analysis further confirmed that tumor cells were the predominant population expressing the transgene. TRIAS-expressing tumor cells exhibited enhanced antitumor activity, likely due to increased cytokine release and upregulated major histocompatibility complex (MHC) expression, enabling tumor cells to function as antigen-presenting cells. This activated other immune cells, driving adaptive immune responses. Additionally, TRIAS promoted a proinflammatory shift in the tumor microenvironment (TME). In conclusion, TRIAS was validated as an innovative immunotherapeutic agent with MAVS-like immune-activating properties and tightly controlled mechanisms, offering a safer and more effective approach for clinical cancer immunotherapy.

Immunogenic cuproptosis in cancer immunotherapy via an in situ cuproptosis-inducing system

Cell death-based therapies combined with immunotherapy have great potential in cancer therapy. To further explore and apply the combined therapies, the immunogenicity of different cell death modes in colorectal cancer (CRC) was evaluated by a cause-and-effect framework encompassing 12 cell death modes. Results show robust correlations among cuproptosis, immunogenic cell death (ICD) and immunity in CRC, as observed in our in-house and other independent cohorts, which are substantiated by in vitro and in vivo experiments. Subsequent investigations demonstrate that cuproptosis induces endoplasmic reticulum stress, leading to the release of damage-associated molecular patterns from CRC cells and triggering the maturation of antigen-presenting cells. Moreover, for in vivo therapeutic approaches, an in situ cuproptosis-inducing system was devised, which can further strengthen the effects of immune cells. Through the combined analysis including single-cell RNA sequencing, cuproptosis is shown to mobilize cytotoxic T lymphocytes and M1 macrophages within the tumor microenvironment (TME). Additionally, co-treatment with Imiquimod, the TLR7 agonist, augments the anti-tumor immune responses induced by cuproptosis. Overall, we provide compelling evidence that cuproptosis induces ICD thus fostering an inflammatory TME, and the cuproptosis-based delivery system further promotes this inflammatory environment, demonstrating considerable potential for enhancing tumor therapy efficacy.

Precision oncolytic viral therapy in colorectal cancer: Genetic targeting and immune modulation for personalized treatment (Review)

Colorectal cancer (CRC) is a leading health issue and treatments to eradicate it, such as conventional chemotherapy, are non‑selective and come with a number of complications. The present review focuses on the relatively new area of precision oncolytic viral therapy (OVT), with genetic targeting and immune modifications that offer a new future for CRC treatment. In the present review, an overview of the selection factors that are considered optimal for an oncolytic virus, mechanisms of oncolysis and immunomodulation applied to the OVT, as well as new strategies to improve the efficacy of this method are described. Additionally, cause‑and‑effect relationships are examined for OVT efficacy, mediated by the tumor microenvironment, and directions for genetic manipulation of viral specificity are explored. The possibility of synergy between OVT and immune checkpoint inhibitors and other treatment approaches are demonstrated. Incorporating the details of the present review, biomarker‑guided combination therapies in precision OVT for individualized CRC care, significant issues and future trends in this required area of medicine are highlighted. Increasingly, OVT is leaving the experimental stage and may become routine practice; it provides a new perspective on overcoming CRC and highlights the importance of further research and clinical work.

Development and Validation of an Immune Prognostic Index Related to Infiltration of CD4+ and CD8+ T Cells in Colorectal Cancer

Colorectal cancer (CRC) is a highly prevalent cancer worldwide, but treatment outcomes can vary significantly among patients with similar clinical or historical stages. This study aimed to investigate the differences in immune cell abundance associated with malignant progression in CRC patients. We utilized data from patients with CRC obtained from The Cancer Genome Atlas as our training set. To assess immune cell infiltration levels, an immune cell risk score (ICRS) was calculated. Furthermore, we performed network analysis to identify effective T cell-related genes (ETRGs) and subsequently constructed an effective T cell prognostic index (ETPI). The performance of the ETPI was evaluated through external validation using four Gene Expression Omnibus datasets. Additionally, a nomogram analysis and drug sensitivity analysis were conducted to explore the clinical utility of the ETRGs. We also examined the expression of ETRGs in clinical samples. Based on the ICRS, we identified activated CD4+ and CD8+ T cells as protective factors in terms of prognosis. Six ETRGs were identified to develop the ETPI, which exhibited remarkable prognostic performance. In the external validation of immunotherapy, the low ETPI group demonstrated a significantly lower recurrence rate. To optimize therapeutic strategies, we developed a nomogram. Notably, patients with different ETPI values exhibited varying responses to tumor pathway inhibitors. Finally, we observed higher protein expression of certain ETRGs in normal tissues compared to tumors. Our findings suggest that the ETPI may contribute to the precise selection of patients based on tumor microenvironment and key genomic landscape interactions, thereby optimizing drug benefits and informing clinical strategies in future.

Mitochondrial gene SLC25A24 regulated anti-tumor immunity and inhibited the proliferation and metastasis of colorectal cancer by PKG1-dependent cGMP/PKG1 pathway

Colorectal cancer (CRC) is a leading cause of cancer-related mortality globally, with metastasis playing a key role in its unfavorable prognosis. Emerging research has emphasized the pivotal role of mitochondria in tumor immune regulation. Nevertheless, the clinical relevance and functional role of SLC25A24, a mitochondrial solute carrier, in CRC remain largely unexplored. Through bioinformatics analyses and validation in clinical cohorts, this study identifies SLC25A24 as an independent prognostic marker in CRC, significantly linked to immune infiltration in CRC tissues. Our findings demonstrated that SLC25A24 expression is markedly reduced in CRC cell lines and tissues. Kaplan-Meier survival analysis revealed that lower SLC25A24 expression is associated with worse overall survival and progression-free survival in CRC patients. Interestingly, SLC25A24 expression was higher in microsatellite instability (MSI) CRC, which shows greater responsiveness to immune checkpoint inhibitors (ICIs). Functional experiments indicated that SLC25A24 overexpression suppresses CRC cell proliferation, migration, and invasion. Mechanistic studies revealed that SLC25A24 positively regulates the cGMP/PKG1 signaling pathway in CRC, influencing mitochondrial potential, apoptosis, and proliferation-related markers. This research highlights the SLC25A24-PKG1 axis as a potential therapeutic target to bolster anti-tumor immunity and curb CRC progression.

High‑dose sodium propionate contributes to tumor immune escape through the IGF2BP3/PD‑L1 axis in colorectal cancer

The understanding of how gut microbiota metabolites modulate immune escape mechanisms in colorectal cancer (CRC) remains limited. In the present study, the impact of gut microbiota metabolites on the efficacy of programmed cell death protein 1 (PD-1) and programmed cell death ligand-1 (PD-L1) immunotherapy in CRC was explored, with a particular focus on the short-chain fatty acid, sodium propionate (SP), as they key metabolite. The results of the present study, determined by CCK-8 and flow cytometry, demonstrated that 10 mM SP significantly suppressed CRC cell proliferation and induced apoptosis. By contrast, 40 mM SP, but not 10 mM, markedly increased the PD-L1 mRNA and protein expression levels. Insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) expression, analyzed via bioinformatics using The Cancer Genoma Atlas datasets, was significantly higher in CRC tissues compared with healthy tissues. Additionally, survival analysis uncovered that elevated IGF2BP3 levels in tumor tissues were strongly associated with poor clinical outcomes. Moreover, 40 mM SP significantly induced the expression of IGF2BP3 mRNA and protein in CRC cells. The actinomycin D assay was conducted to assess mRNA stability, whereas methylated RNA immunoprecipitation coupled with quantitative polymerase chain reaction (qPCR) and RNA immunoprecipitation-qPCR were utilized to confirm the interaction between IGF2BP3 and PD-L1 mRNA. These results indicated that IGF2BP3 served as an N6-methyladenosine (m6A) reader for PD-L1, stabilizing its mRNA in an m6A-dependent manner, thereby upregulating the PD-L1 mRNA and protein expression levels. Therefore, high-dose SP may promote tumor immune escape via the IGF2BP3/PD-L1 axis in CRC. As such, high-dose SP may synergize with PD-1/PD-L1 blockade therapies to improve clinical outcomes in patients with CRC, particularly by upregulating PD-L1 expression.

m6A-mediated regulation of CPSF6 by METTL3 promotes oxaliplatin resistance in colorectal cancer through enhanced glycolysis

Oxaliplatin resistance poses a significant challenge in colorectal cancer (CRC) treatment. Recent studies have implicated CPSF6 in cancer progression and drug resistance, although its role in chemotherapy resistance and regulatory mechanisms is unclear. This study investigates CPSF6's involvement in oxaliplatin resistance in CRC and its regulation via m6A methylation by METTL3. We assessed CPSF6 expression in oxaliplatin-resistant (OxR) CRC cell lines (HT29-OxR and HCT116-OxR) compared to sensitive counterparts using qRT-PCR and Western blotting. CPSF6 was significantly upregulated in OxR cells, and its knockdown reduced cell viability, colony formation, and glycolytic activity while increasing apoptosis. m6A modification of CPSF6 mRNA was elevated in OxR cells, correlating with increased METTL3 expression. METTL3 knockdown decreased CPSF6 levels and m6A enrichment, enhancing mRNA degradation, while its overexpression stabilized CPSF6 mRNA, promoting resistance. Xenograft experiments showed that CPSF6 knockdown suppressed tumor growth and glycolysis. Thus, CPSF6 is identified as a mediator of oxaliplatin resistance in CRC, regulated by the METTL3/m6A axis, suggesting potential therapeutic targets to overcome resistance.

Network pharmacology combined with transcriptomics reveals that Ganoderma lucidum spore and Sanghuangporus vaninii compound extract exerts anti-colorectal cancer effects via CYP24A1-mediated VDR pathway and TERT-mediated Wnt signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

As traditional medicinal fungi, Ganoderma lucidum and Sanghuangporus vaninii are widely used in the treatment of tumor related diseases and cancer adjuvant therapy with potent anticancer effects. However, the anticancer effect and mechanism of action of their compound extract remain unclear.

AIM OF THE STUDY

To investigate the anticancer effect of Ganoderma lucidum and Sanghuangporus vaninii compound extract and explore the underlying mechanism.

MATERIALS AND METHODS

First, MTT assay was performed to investigate the effect of 8 different extracts on tumor cell viability. Moreover, the synergistic effect of Ganoderma lucidum spore and Sanghuangporus vaninii was evaluated by Chou-Talalay method. Subsequently, the fractional extractions were conducted to further isolate anti-tumor active components. Next, network pharmacology combined with transcriptomics was used to explore the potential mechanisms underlying the anticancer effect of compound extract. Finally, the mechanism of action was verified using in vitro and in vivo models.

RESULTS

Among all 8 extracts, Ganoderma lucidum spore and Sanghuangporus vaninii compound ethanol extract (GSEE) showed the most significant cell viability inhibitory effect on cancer cells, especially colorectal cancer (CRC) cells, which was even better than combination of Sanghuangporus vaninii ethanol extract (SVEE) and Ganoderma lucidum spore ethanol extract (GLEE). The ethyl acetate fraction of GSEE (GSEAE) was screened as the anti-tumor active fraction of GSEE and could suppress CRC proliferation in vitro and in vivo. The CYP24A1-mediated Vitamin D receptor (VDR) pathway and TERT-mediated Wnt signaling pathway were identified as the main mechanisms of GSEAE against CRC. Multiple CRC models confirmed that GSEAE suppressed CRC metastasis, arrested cell cycle and induced mitochondrial apoptosis of CRC cells via VDR pathway and Wnt signaling pathway.

CONCLUSIONS

Collectively, our data suggest that compound extract GSEAE exerts anti-CRC effects via CYP24A1-mediated VDR pathway and TERT-mediated Wnt signaling pathway.

Research advances of PANoptosis in gastrointestinal tumors

Gastric and colorectal cancers are acknowledged as the predominant types of gastrointestinal malignancies, significantly impacting the global cancer burden. Despite advancements in basic and clinical research on gastrointestinal cancer, the pathophysiological mechanisms and developmental processes underlying these diseases remain incompletely understood. The dysregulation of programmed cell death (PCD) has been identified as a crucial factor in the progression and metastasis of malignant tumors. The effective induction of cancer cell death continues to present a major challenge in contemporary cancer research. PANoptosis, a distinctive form of PCD integrating apoptosis, pyroptosis, and necroptosis, was introduced in 2019. Upon detecting relevant stimuli, PANoptosis sensors recruit key molecules from the three death modalities through domain-specific interactions to form a PANoptosome, which executes cell death. Recent discoveries suggest that PANoptosis plays a pivotal role in the development, progression, and drug resistance of gastrointestinal cancer. Enhancing PANoptosis will provide superior control over gastrointestinal tumors through multi-pathway crosstalk and inflammatory microenvironment modulation. This review aims to serve as a comprehensive resource for researchers by exploring the molecular foundation of PANoptosis, emphasizing its importance in gastrointestinal tumor development, and addressing current challenges as well as potential future research directions in this field.

Emerging roles of non-coding RNA derived from extracellular vesicles in regulating PD-1/PD-L1 pathway: insights into cancer immunotherapy and clinical applications

Numerous studies have demonstrated that extracellular vesicles (EVs) carry a variety of noncoding RNAs (ncRNAs), which can be taken up by neighboring cells or transported to distant sites via bodily fluids, thereby facilitating intercellular communication and regulating multiple cellular functions. Within the tumor microenvironment, EV-ncRNA, on the one hand, regulate the expression of PD-L1, thereby influencing tumor immune evasion, promoting tumor cell proliferation, and enhancing tumor growth, invasion, and metastasis in vivo. On the other hand, these specific EV-ncRNAs can also modulate the functions of immune cells (such as CD8 + T cells, macrophages, and NK cells) through various molecular mechanisms, inducing an immunosuppressive microenvironment and promoting resistance to anti-PD-1 therapy. Therefore, delving into the molecular mechanisms underlying EV-ncRNA regulation of immune checkpoints presents compelling therapeutic prospects for strategies that selectively target EV-ncRNAs. In this review, we elaborate on the cutting-edge research progress related to EV-ncRNAs in the context of cancer and dissect their pivotal roles in the PD-1/PD-L1 immune checkpoint pathway. We also highlight the promising clinical applications of EV-ncRNAs in anti-PD-1/PD-L1 immunotherapy, bridging basic research with practical clinical applications.

The role of Sine Oculis Homeobox Homolog 2 in colon Cancer: Insights into prognosis, immune regulation, and therapeutic implications

Colon cancer (CC) remains a significant global health burden, and the search for novel prognostic biomarkers and therapeutic targets is crucial. This study comprehensively analyzed the role of SIX2 (Sine Oculis Homeobox Homolog 2) in CC. Utilizing data from TCGA, GTEx, and CCLE databases, differential expression of SIX2 was observed in multiple cancers, with significant upregulation in many tumors compared to normal tissues. In CC, SIX2's differential expression was notable. Cox regression analysis revealed its prognostic significance, with overexpression associated with poor survival outcomes. SIX2 was strongly associated with gene alterations and correlated with key signaling pathways like WNT and TGF-β. In the tumor microenvironment, SIX2 was related to immune cell infiltration and immune-related molecules. Notably, in CC, it was associated with immunosuppressive cells and checkpoint molecules. Additionally, ABT737 was found to sensitize tumor immunotherapy in the context of SIX2. Animal experiments demonstrated that ABT737 effectively restricted the growth of CC in mice, and its combination with antiPD-1 immunotherapy was more effective. It could reduce the infiltration of CD163+ tumor-associated macrophages but without significantly increasing the infiltration of CD8+ T cells. Our findings suggest that SIX2 is a potential key player in CC, offering insights into future research and the development of targeted therapies.

NCOA3 impairs the efficacy of anti-PD-L1 therapy via HSP90α/EZH2/CXCL9 axis in colon cancer

Immune checkpoint inhibitors (ICIs) have revolutionized colon cancer treatment, but their efficacy is largely restricted by the limited presence of CD8+ cytotoxic T lymphocytes (CTLs). However, the specific genetic alterations that impact the CD8+ CTL infiltration in colon cancer remain poorly understood. Here, we analyzed clinical and multi-omics data from the Memorial Sloan-Kettering Cancer Center (MSKCC) ICIs-treated and The Cancer Genome Atlas (TCGA) colon adenocarcinoma (COAD) cohorts to screen the key mutations that may influence the efficacy of immunotherapy. We found that patients with NCOA3 mutations exhibit better response to immunotherapy and higher CD8+ CTL infiltration. In vitro and in vivo experiments revealed that mutant NCOA3 increases the efficacy of anti-PD-L1 and CD8+ CTL recruitment by upregulating C-X-C motif chemokine ligand 9 (CXCL9), which is dependent on its impaired intrinsic histone acetyltransferase activity. Mechanistically, wild-type NCOA3 as histone acetyltransferase upregulates Heat shock protein 90 alpha (HSP90α) by enhancing histone H3 lysine 27 acetylation (H3K27ac) at its promoter region. Increased HSP90α stabilizes Enhancer of zeste homolog 2 (EZH2), which then increase the histone H3 lysine 27 trimethylation (H3K27me3) at the CXCL9 promoter region, thereby suppressing the expression of CXCL9. Targeted inhibition of NCOA3 by small molecular inhibitor SI-2 improves the efficacy of PD-L1 blockade therapy. NCOA3 could serve as a novel biomarker and potential target to improve the efficacy of immunotherapy.

Computed tomography-based deep learning radiomics model for preoperative prediction of tumor immune microenvironment in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is a leading cause of cancer-related death globally, with the tumor immune microenvironment (TIME) influencing prognosis and immunotherapy response. Current TIME evaluation relies on invasive biopsies, limiting its clinical application. This study hypothesized that computed tomography (CT)-based deep learning (DL) radiomics models can non-invasively predict key TIME biomarkers: Tumor-stroma ratio (TSR), tumor-infiltrating lymphocytes (TILs), and immune score (IS).

AIM

To develop a non-invasive DL approach using preoperative CT radiomics to evaluate TIME components in CRC patients.

METHODS

In this retrospective study, preoperative CT images of 315 pathologically confirmed CRC patients (220 in training cohort and 95 in validation cohort) were analyzed. Manually delineated regions of interest were used to extract DL features. Predictive models (DenseNet-121/169) for TSR, TILs, IS, and TIME classification were constructed. Performance was evaluated via receiver operating characteristic curves, calibration curves, and decision curve analysis (DCA).

RESULTS

The DL-DenseNet-169 model achieved area under the curve (AUC) values of 0.892 [95% confidence interval (CI): 0.828-0.957] for TSR and 0.772 (95%CI: 0.674-0.870) for TIME score. The DenseNet-121 model yielded AUC values of 0.851 (95%CI: 0.768-0.933) for TILs and 0.852 (95%CI: 0.775-0.928) for IS. Calibration curves demonstrated strong prediction-observation agreement, and DCA confirmed clinical utility across threshold probabilities (P < 0.05 for all models).

CONCLUSION

CT-based DL radiomics provides a reliable non-invasive method for preoperative TIME evaluation, enabling personalized immunotherapy strategies in CRC management.

KLRG1 expression induces functional exhaustion of NK cells in colorectal cancer patients

BACKGROUND

Natural killer (NK) cells are a subset of innate lymphoid cells that possess cytotoxic properties, playing a pivotal role in immune surveillance against tumor cells. However, it remains unclear whether there are any alterations in the quantity and functional status of NK cells in colorectal cancer (CRC).

METHODS

In this study, we collected peripheral blood samples from both CRC patients and age- and sex-matched healthy controls (HCs). The distribution characteristics, phenotypic changes, functional status, apoptosis susceptibility, and proliferative capacity of circulating NK cells were detected and analyzed by flow cytometry. An in vitro study was performed to investigate the blocking effect of KLRG1 antibody on peripheral blood NK cells in CRC patients.

RESULTS

The frequency and absolute number of circulating NK cells were significantly decreased in CRC patients compared to those in HCs. Meanwhile, the function of NK cells from CRC patients was compromised, as shown by the reduced production of IFN-γ, TNF-α, and CD107a, with this impairment becoming increasingly significant as neural invasion progressed and tumor invasion advanced. We further found that the expression of activating receptors NKp30 and NKp46 were reduced, while the expression of inhibitory receptor KLRG1 was remarkably increased. The increased proportion of KLRG1 on NK cells was associated with CRC progression, and KLRG1+ NK cells showed impaired production of IFN-γ, TNF-α, and CD107a and were more susceptible to apoptosis. Importantly, blockade of the KLRG1 pathway could restore the cytokine production and degranulation ability of NK cells from CRC patients.

CONCLUSIONS

The present study demonstrates that NK cells in CRC patients exhibit functional exhaustion, and KLRG1 blockade restores the effector function of NK cells, indicating that targeting KLRG1 represents a promising strategy for immunotherapy in patients with CRC.

Construction and validation of a prognostic model for colorectal cancer based on migrasome-related long non-coding RNAs

Background

Colon adenocarcinoma (COAD) is a globally prevalent and deadly malignancy of the digestive system. Recently, migrasomes have gained significant attention as important regulators of tumor cell migration and metastasis. The current research developed a highly accurate prognostic model using migrasome-related long non-coding RNAs (lncRNAs) in COAD, providing new insights for prognostic assessment and immunotherapy of COAD patients.

Methods

RNA sequencing data from COAD patients were acquired from The Cancer Genome Atlas Program (TCGA) database to construct a prognostic lncRNA model based on known migrasome-related genes (MRGs). The model's predictive accuracy was then assessed using concordance index (C-index) analysis, nomograms, principal component analysis, and receiver operating characteristic curves. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted to identify significant differences in biological functions and signaling pathways associated with differentially expressed genes in the high-risk subgroup. A comprehensive evaluation of the model incorporated clinical-pathological features, tumor microenvironment, and chemotherapy sensitivity. The expression levels of prognostic genes in COAD patients were validated via quantitative reverse transcription polymerase chain reaction (RT-qPCR). Furthermore, the role of LCMT1-AS1 in colorectal cancer was examined through CCK-8 assays, colony formation assays, and Transwell experiments.

Results

Migrasome-related lncRNAs were identified as robust prognostic predictors for COAD. Multivariate analysis revealed that the risk score derived from these lncRNAs is an independent prognostic factor for COAD. Patients in the low-risk group exhibited significantly longer overall survival (OS) compared to those in the high-risk group. Accordingly, the nomogram prediction model we developed, which integrates clinical features and risk scores, demonstrated excellent prognostic performance. In vitro experiments further showed that LCMT1-AS1 promotes the proliferation and migration of COAD cells.

SOX17: a new therapeutic target for immune evasion of colorectal cancer

Despite advances in cancer immunotherapies across various cancers, survival outcomes in colorectal cancer (CRC) with these agents remain largely unsatisfactory despite the high tumour burden. Colorectal stem cells (CSCs), especially LGR5+ CSCs, are the significant drivers in CRC initiation, progression and resistance to conventional therapies. Although native immune surveillance is sufficient to combat early tumour formation, CRC evades early immune detection with its well-documented adenoma-to-carcinoma sequence. The exact mechanism underlying this phenomenon still needs to be better understood. SRY-related HMG box gene 17 (SOX17), a transcription factor that specifies embryonic gut formation, is increasingly recognised as a significant factor in CRC tumourigenesis. However, its role as a tumour suppressor or oncogene is still debated. Evidence from a recent study highlighted the critical role of SOX17 in reshaping the tumour immune ecosystem through the simultaneous inhibition of CD8+ T cells and selective suppression of LGR5 expression in CSCs through transcriptional repression, thereby facilitating disease progression. Given its role in immune evasion, SOX17 could be a promising marker in personalised therapy. Additionally, SOX17 could play a role in the diagnostic arena, potentially identifying dysplasia in the gastrointestinal tract. Future clinical, basic and genetic studies focusing on SOX17 are needed to ascertain its mechanistic role in tumour immunomodulation in CRC and diagnosing preneoplastic lesions in the gastrointestinal tract.

Artificial intelligence in colorectal cancer liver metastases: From classification to precision medicine

Colorectal cancer liver metastasis (CRLM) remains the leading cause of mortality among colorectal cancer (CRC) patients, with more than half eventually developing hepatic metastases. Achieving long-term survival in CRLM necessitates early detection, robust stratification, and precision treatment tailored to individual classifications. These processes encompass critical aspects such as tumor staging, predictive modeling of therapeutic responses, and risk stratification for survival outcomes. The rapid evolution of artificial intelligence (AI) has ushered in unprecedented opportunities to address these challenges, offering transformative potential for clinical oncology. This review summarizes the current methodologies for CRLM grading and classification, alongside a detailed discussion of the machine learning models commonly used in oncology and AI-driven applications. It also highlights recent advances in using AI to refine CRLM subtyping and precision medicine approaches, underscoring the indispensable role of interdisciplinary collaboration between clinical oncology and the computational sciences in driving innovation and improving patient outcomes in metastatic colorectal cancer.

Identification of the "Collagen-Macrophage" sub-category of patients with colorectal cancer as an extension of the CMS4 subtype with THBS2 as a therapeutic target

We identified a subset of patients with colorectal cancer (CRC) enriched with "collagen-TAMs," designated the CM class, using large integrated colon cancer transcriptome and single-cell transcriptome datasets. This classification system could be used as an extension of the traditional CMS classification system for CRC to guide more accurate classification and treatment.We also screened CAF-derived THBS2 as a potential biomarker for CM and found that it plays an important role in CRC disease models in vitro and in vivo, promoting tumor development and metastasis as well as TAM recruitment. Targeting THBS2 combined with PD-1 therapy effectively improved the therapeutic effect of immunotherapy in vivo. The CM classification provides a new perspective for CRC treatment, and THBS2, which is highly expressed in CM cases, can be used as a new potential combined target for immunotherapy.

Mn-coordination driven glutamine and cancer stemness dual-tailored nano-herb for high-efficiency activation of dendritic cells

Dendritic cells (DCs), as specialized antigen-presenting cells, are the commanders of the human immune cell system, directing and controlling various functions of the immune system. However, the competitive plunder of glutamine by tumor cells and the cancer cell stemness significantly impair the functional activation of DCs. Herein, we developed a Mn-coordination driven glutamine and cancer stemness dual-tailored nano-herb (HA/E-M@Purpurin NPs) for high-efficiency activation of DCs. The nano-herb is composed of ellagic acid (EA), divalent manganese ion (Mn2+), and purpurin. EA exerts an inhibitory effect on cell stemness, Mn2+ activate DCs by activating the cGAS-STING pathway, and purpurin inhibits the breakdown of glutamine, leading to a compensatory increase in glutamine content and further activating DCs. After surface modification with hyaluronic acid (HA), the nano-herb can target tumor cells and release drugs to exert corresponding effects. Taken together, our findings underscore the substantial promise of nano-herbs in overcoming cancer stemness-driven immune escape, offering a transformative approach to enhance the success of immunotherapy regimens.

Single-cell and bulk transcriptome sequencing identifies circadian rhythm disruption and cluster-specific clinical insights in colorectal tumorigenesis

BACKGROUND

Colorectal cancer (CRC) is one of the most common malignant tumors in the digestive system worldwide, with its mortality ranking second among all cancers. Studies have indicated that disruptions in circadian rhythm (CR) are associated with the occurrence of various cancers; however, the relationship between CR and CRC requires further evidence, and research on the application of CR in CRC is still limited.

METHODS

In this study, we employed both bulk and single-cell RNA sequencing to explore the dysregulation of CR in patients with CRC. By constructing a CR subtype classifier, we conducted an in-depth analysis of the prognostic significance, the status of the tumor microenvironment, and response to immune checkpoint blockade (ICB) therapy between different CR clusters. Furthermore, we developed a CR scoring system (CRS) using machine learning to predict overall survival and identified several genes as potential targets affecting CRC prognosis.

RESULTS

Our findings revealed significant alterations in CR genes and status between CRC and normal tissues using bulk and single-cell transcriptome sequencing. Patients with CRC could be categorized into two distinct CR clusters (CR cluster 1 and 2). The prognosis of CR cluster 2, with higher epithelial-mesenchymal transition (EMT) and angiogenesis scores, was significantly worser than that of CR cluster 1. These clusters exhibited distinct levels of tumor-infiltrating lymphocytes. CR cluster 2 with a notably higher proportion of patients with microsatellite-instability-high (MSI-H), potentially benefit from ICB therapy. The proportion of patients belonging to consensus molecular subtype 4 (CMS4) in CR cluster 2 was also notably higher than in CR cluster 1. Additionally, the CRS combined with tumor stage demonstrated superior overall survival prediction efficacy compared to traditional tumor stage. We revealed a potential link between model genes (LSAMP, MS4A2, NAV3, RAB3B, SIX4) and the disruption of CR and patient prognosis.

CONCLUSION

This study not only provide new insights into the assessment of CR status in CRC patients but also develop a prognosis model based on CR-related genes, offering a new tool for personalized risk assessment in CRC.

Partial response to posterior line immunotherapy for more than 15 months in a pMMR patient with cutaneous metastasis of rectal carcinoma: a case report

The vast majority of colorectal cancers (CRCs) are proficient mismatch repair (pMMR) and microsatellite stable, and their immune microenvironment appears as a "cold tumor," which is not sensitive to single immunotherapy based on immune checkpoint inhibitors (ICIs). The utilization of ICIs in pMMR advanced CRC is still in the exploratory phase. Cutaneous metastasis from colorectal carcinoma is extremely rare, presenting with diverse clinical manifestations, and there is a lack of standard treatment options for such cases. Patients with skin metastasis from CRC usually progress rapidly and are associated with a dismal prognosis. Herein, we report the case of a 66-year-old woman with extensive cutaneous metastasis of pMMR advanced rectal carcinoma. The patient presented to the abdominal oncology clinic with a complaint of erythema on the right lower limb, perineum, and abdominal skin. The patient underwent radical surgery for rectal carcinoma 3 years before the presentation. The histologic examination revealed low-grade squamous cell subepithelial adenocarcinoma. The patient was treated with sintilizumab in combination with fruquintinib, which exhibited remarkable efficacy and improved the patient's quality of life significantly. Previous cases of cutaneous metastasis of colorectal carcinoma were retrieved to characterize the clinicopathological features. For the rare subset of patients with skin metastasis from CRC, immunotherapy combined with anti-angiogenic targeted therapy may be considered.

Neoadjuvant Pembrolizumab Enables Successful Downstaging and Resection of Borderline Resectable MSI-H/dMMR Pancreatic Ductal Adenocarcinoma: A Case Report and Literature Review

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with a poor prognosis. While immunotherapy has shown limited efficacy in most PDAC cases due to an immunosuppressive tumour microenvironment, tumours with microsatellite instability-high (MSI-H) or deficient mismatch repair (dMMR) status exhibit increased responsiveness to immune checkpoint inhibitors.

CASE PRESENTATION

We report the case of a 45-year-old woman with Lynch syndrome who was diagnosed with MSI-H/dMMR PDAC during routine surveillance. Given the borderline resectable nature of her tumour and previous chemotherapy-related neurotoxicity, she was treated with neoadjuvant pembrolizumab instead of conventional chemotherapy. Following four cycles of pembrolizumab, imaging revealed a marked metabolic response, allowing for successful R0 pancreatoduodenectomy. Postoperative histology confirmed a significant reduction in tumour size, and immunohistochemical analysis demonstrated increased CD8 + T cell infiltration, supporting an enhanced anti-tumour immune response. The patient continues adjuvant pembrolizumab therapy without complications.

CONCLUSION

This case highlights the potential role of neoadjuvant pembrolizumab in MSI-H/dMMR PDAC, demonstrating successful tumour downstaging and facilitating surgical resection. Our findings support further investigation into the integration of immunotherapy as a neoadjuvant strategy for select PDAC patients.

DBI as a Novel Immunotherapeutic Candidate in Colorectal Cancer: Dissecting Genetic Risk and the Immune Landscape via GWAS, eQTL, and pQTL

Background: Colorectal cancer (CRC) is a leading cause of cancer-related mortality worldwide. Identifying drug targets associated with CRC is crucial for developing targeted therapies. Methods: MR (IVW, Wald ratio, weighted median, and MR-Egger) and SMR analyses were used to screen candidate genes associated with CRC risk. Further validation was performed using The Cancer Genome Atlas (TCGA) to assess gene expression patterns and prognostic significance. Additionally, immune infiltration analysis was conducted to characterize the tumor immune microenvironment. Drug prediction was performed to explore potential therapeutic interventions. Results: Eight genes were identified associated with CRC. IGFBP3, CD72, SERPINH1, CHRDL2, LRP11, and SPARCL1 were linked to an increased risk of CRC, whereas DBI and HYAL1 were associated with a decreased risk of CRC. Notably, DBI exhibited a potentially favorable immune profile, negatively correlated with Tregs and MDSCs while positively associated with activated CD8+ and CD4+ T cells. Conclusions: Eight genes were identified as associated with CRC, among which DBI exhibited a potential protective role, correlating with improved patient survival, enhanced immune activation, and increased responsiveness to immunotherapy. The remaining proteins demonstrated diverse and complex functions within the tumor immune microenvironment, providing novel insights for the development of precision diagnostics and immunotherapeutic strategies.

PAR2 deficiency impairs antitumor immunity and attenuates anti-PD1 efficacy in colorectal cancer

A T cell-inflamed tumor microenvironment is predictive of better prognosis and clinical response to immunotherapy. Proteinase-activated receptor 2 (PAR2), a member of G-protein coupled receptors is involved in inflammatory process and the progression of various cancers. However, the role of PAR2 in modulating the tumor microenvironment remains unclear. Here, we found that PAR2 high-expression was associated with a favorable prognosis in patients with colorectal cancer. Intriguingly, PAR2 expression in human colorectal cancer was mainly confined to tumor cells and was significantly associated with CD8+ T cell infiltration. Tumor-intrinsic PAR2 deficiency blunted antitumor immune responses to promote tumor growth and attenuated the therapeutic efficacy of anti-PD1 in a mouse model of colon cancer. Tumors with downregulated PAR2 showed decreased CD8+ T cell infiltration and impaired effector function. Mechanistically, PAR2 activation in tumor cells induced CXCL9 and CXCL10 production via PI3K/AKT/mTOR signaling, thereby enhancing CD8+ T cell recruitment in the tumor microenvironment. In addition, PAR2 was essential for dendritic cell activation and differentiation towards conventional type 1 subset. PAR2 deficiency in dendritic cells markedly impaired their ability to prime CD8+ T cells and control tumor growth in vivo. Thus, our findings identify new roles for PAR2 in promoting antitumor immunity and provide a promising target to improve immunotherapy efficacy in colorectal cancer.

VSIG4 Promotes Tumour-Associated Macrophage M2 Polarization and Immune Escape in Colorectal Cancer via Fatty Acid Oxidation Pathway

BACKGROUND

V-set and immunoglobulin domain containing 4 (VSIG4) is a B7-family-related protein almost exclusively expressed on macrophages. The difference in its expression mediates the dynamic transformation of the polarization state of macrophages, but the underlying mechanism is still unclear. We sought to reveal the correlation between VSIG4 and the polarization of tumour-associated macrophages (TAMs) and the immune escape of tumour cells in colorectal cancer (CRC).

METHODS

THP-1 monocyte-derived macrophages expressing different levels of VSIG4 were used for in vitro investigations. In addition, the co-culture system was used to verify the effect of tumour cells on the expression of VSIG4 in macrophages, and the effect of VSIG4 expression level on tumour cells in turn. Subcutaneous xenograft models evaluated the tumour growth inhibition efficacy of VSIG4 blockade as monotherapy and combined with immune checkpoint inhibitors (ICIs).

RESULTS

CRC cells secreted lactate to promote VSIG4 expression in macrophages. On the contrary, VSIG4 promoted macrophage M2 polarization and induced malignant progression of tumour cells by promoting M2 macrophage secretion of heparin-bound epidermal growth factor. In vivo experiments confirmed that knockdown VSIG4 inhibited tumour growth and improved the efficacy of ICIs therapy. Mechanistically, lactate secreted by CRC cells promoted its expression by influencing the epigenetic modification of VSIG4 in macrophages. In addition, VSIG4 enhanced the fatty acid oxidation (FAO) of macrophages and upregulated PPAR-γ expression by activating the JAK2/STAT3 pathway, which ultimately induced M2 polarization of macrophages. Downregulation of VSIG4 or blocking of FAO reversed the M2 polarization process of macrophages.

CONCLUSIONS

Our findings provide a molecular basis for VSIG4 to influence TAMs polarization by regulating the reprogramming of FAO, suggesting that targeting VSIG4 in macrophages could enhance the ICIs efficacy and represent a new combination therapy strategy for immunotherapy of CRC.

KEY POINTS

Colorectal cancer cells secrete lactate to upregulate VSIG4 in macrophages via the H3K18la-METTL14-m6A axis. VSIG4 promotes fatty acid oxidation of macrophages and drives its M2-type polarization. These VSIG4-expressing M2 macrophages promote tumour progression and an immunosuppressive microenvironment. Inhibition of VSIG4 expression can synergistically enhance the therapeutic effect of anti-PD-1 antibody.

Carnitine palmitoyltransferase 2 as a novel prognostic biomarker and immunoregulator in colorectal cancer

BACKGROUND

Metabolic interventions are critical for enhancing immunotherapy efficacy, but reliable metabolic targets remain absent for colorectal cancer (CRC). This study aims to investigate the interplay between metabolic and immunological factors in CRC, identify metabolic immunoregulatory molecules, and propose targets for prognostic and therapeutic applications.

METHODS

Immune infiltration and metabolic pathways in CRC were analyzed using CIBERSORT and gene set variation analyses. Cox regression identified survival-related metabolic genes, forming a metabolic-related gene prognostic index (MRGPI), which was validated through survival analysis, timeROC, GSEA, CIBERSORT, and TIDE. Hub genes in the MRGPI were assessed using enrichment and co-expression network analyses. The expression of carnitine palmitoyltransferase 2 (CPT2) was validated through multiplex immunofluorescence of tissue microarrays. While its role was examined by western blot, CCK-8 assay, flow cytometry, qRT-PCR, Elisa, chemotaxis assays, etc. RESULTS: Fatty acid oxidation (FAO) pathways were significantly altered in CRC and correlated with immune cell infiltration and patient survival. The MRGPI, constructed from five survival-related metabolic genes, demonstrated strong prognostic and immunotherapeutic predictive value. Moreover, CPT2, a key hub gene in the MRGPI, whose lower expression in plasma cells predicts unfavorable patients' survival and could be an independent prognostic indicator, while its knockout in tumor cells significantly increases the infiltrating levels of CD8+ T cells via promoting the release of CCL25.

CONCLUSION

The FAO-dominated MRGPI is a promising biomarker for predicting patient outcomes and immunotherapy response. CPT2 holds potential as a prognostic marker and therapeutic target for CRC metabolic immunotherapy.

BRAF mutation cancer, colorectal cancer, tumor associated lymph node structure and immune microenvironment study: MAPK protein kinase molecular action and SIRPG-CD47 protein signaling pathway

BRAF mutation affects the biological characteristics and microenvironment of the tumor during the development of colorectal cancer. Tumor-associated lymph nodes are the key sites of immune response. This study aimed to systematically evaluate the impact of BRAF gene mutations on the remodeling of the CRC immune microenvironment, with a particular focus on their effects on the maturation and function of TLS·In this study, clinical samples of CRC patients were collected, and immune cell subsets were analyzed by single-cell RNA sequencing, and pseudo-temporal locus analysis and spatial transcriptome analysis were performed to explore intercellular communication and functional enrichment analysis. The distribution and maturity of TLS were evaluated by immunohistochemistry and multiple fluorescence staining techniques, and statistical analysis was performed.The results showed that BRAF mutation significantly affected the number and maturity of lymphatic structures infiltrated by tumors, and was negatively correlated with patient prognosis. BRAF mutations lead to alterations in T cell subsets, particularly the dual role of CD4+ CXCL13 cells in TLS maturation. B-cell subpopulation analysis revealed functional deficits in CRC patients with BRAF mutations, which further drove the remodeling of the tumor immune microenvironment.

Clinical development of immuno-oncology therapeutics

Immuno-oncology (IO) is one of the fastest growing therapeutic areas within oncology. IO agents work indirectly via the host's adaptive and innate immune system to recognize and eradicate tumor cells. Despite checkpoint inhibitors being only introduced to the market since 2011, they have become the second most approved product category. Current Food and Drug Administration (FDA)-approved classes of IO agents include: immune checkpoint inhibitors (ICIs), chimeric antigen receptor T-cell therapy (CAR-T), bi-specific T-cell engager (BiTE) antibody therapy, T-cell receptor (TCR) engineered T cell therapy, tumor-infiltrating lymphocyte (TIL) therapy, cytokine therapy, cancer vaccine therapy, and oncolytic virus therapy. Cancer immunotherapy has made progress in multiple cancer types including melanoma, non-small cell lung cancer (NSCLC), renal cell carcinoma (RCC), and urothelial carcinoma; however, several cancers remain refractory to immunotherapy. Future directions of IO include exploration in the neoadjuvant/perioperative setting, combination strategies, and optimizing patient selection through improved biomarkers.

Understanding the cellular and molecular heterogeneity in colorectal cancer through the use of single-cell RNA sequencing

The very prevalent nature, genetic variability, and intricate tumor microenvironment (TUME) of colorectal cancer (COREC) are its defining features. In order to better understand the molecular and cellular make-up of COREC, this work used single-cell RNA sequencing (SRNAS) to isolate and characterize important cell types as well as their interactions within the TUME. Our analysis of 51,204 cells yielded six distinct types: epithelial, fibroblast, endothelial, T&NK, B, and myeloid. C3 B cells were shown to be the most active in immunological regulation, according to chemokine signaling study, which was one of seven clusters of B cells that were thoroughly subtyped. The examination of copy number variation (CONUV) revealed a great deal of genetic variability, especially in epithelial cells. We traced the activity of three key transcription factor clusters (M1, M2, and M3) across all B cell subtypes using transcription factor analysis. We created a predictive model that correctly sorts patients according to survival results by using marker genes from C3 B cells. In addition, the relationship between genetic changes and the immune system was better understood by tumor mutational burden (TUMUB) and immune infiltration studies. Our research sheds light on the genetic complexity and cellular variety of COREC, which in turn opens up new possibilities for targeted treatments and individualized approaches to patient care.

Lysine-specific demethylase 1 deletion reshapes tumour microenvironment to overcome acquired resistance to anti-programmed death 1 therapy in liver cancer

BACKGROUND

Immune checkpoint blockade, particularly targeting programmed death 1 (PD-1) and programmed death ligand 1 (PD-L1), shows promise in treating hepatocellular carcinoma (HCC). However, acquired resistance, especially in patients with 'hot tumours', limits sustained benefits. Lysine-specific demethylase 1 (LSD1) plays a role in converting 'cold tumours' to 'hot tumours', but its involvement in PD-1 inhibitor resistance in HCC is unclear.

METHODS

LSD1 and PD-L1 expression, along with CD8+ T cell infiltration, were assessed using immunohistochemistry in HCC tissues, correlating these markers with patient prognosis. The impact of LSD1 deletion on tumour cell proliferation and CD8+ T cell interactions was examined in vitro. Mouse models were used to study the combined effects of LSD1 inhibition and anti-PD-1 therapy on tumour growth and the tumour microenvironment (TME). The clinical relevance of LSD1, CD74 and effector CD8+ T cells was validated in advanced HCC patients treated with PD-1 blockade.

RESULTS

LSD1 overexpression in HCC patients correlated with reduced PD-L1 expression, less CD8+ T cell infiltration and poorer prognosis. LSD1 deletion increased PD-L1 expression, boosted effector CD8+ T cells in vitro and inhibited tumour growth in vivo. While anti-PD-1 monotherapy initially suppressed tumour growth, it led to relapse upon antibody withdrawal. In contrast, combining LSD1 inhibition with anti-PD-1 therapy effectively halted tumour growth and prevented relapse, likely through TME remodelling, enhanced CD8+ T cell activity and improved CD74-mediated antigen presentation. Clinically, low LSD1 expression was associated with better response to anti-PD-1 therapy.

CONCLUSION

LSD1 deletion reshapes the TME, enhances CD8+ T cell function and prevents acquired resistance to anti-PD-1 therapy in HCC. The combination of LSD1 inhibitors and PD-1 blockade offers a promising strategy for overcoming resistance in advanced HCC.

KEY POINTS

Uncovering the synthetic lethality resulting from LSD1 deletion and PD1 inhibitor co-administration, evaluating their combined effects on tumour growth and TME remodelling. Elucidating the mechanism underlying the combined therapy of LSD1 deletion with PD1 inhibition for HCC. Exploring the implications of LSD1, CD74 and effector CD8+ T cell expression levels in advanced HCC patients undergoing anti-PD1 treatment.

The role of tumor-associated fibroblast-derived exosomes in chemotherapy resistance of colorectal cancer and its application prospect

Colorectal cancer (CRC) is the second most common malignant tumor in the world. With its increasing incidence and younger age trend, its impact on human health has been paid more and more attention. Currently, we have a variety of chemotherapy drugs that can be used to treat colorectal cancer. However, the drug resistance of colorectal cancer has become a significant factor affecting its cure rate. Some studies have reported that exosomes are related to the occurrence of drug resistance. However, the exact mechanism is not precise. Therefore, we focused on the role of cancer associated-fibroblast-derived (CAFs-derived) exosomes in colorectal progression. It was found that cancer cells transmit information through exosome interaction and induce chemotherapy resistance by promoting epithelial-mesenchymal transition (EMT), up-regulating the Wnt/β-catenin signaling pathway, transforming growth factor-β1 (TGF-β1) pathway, promoting angiogenesis and other possible molecular mechanisms. In addition, in terms of clinical significance and therapeutic strategies, we explore the clinical relevance of CAFs-derived exosomes in colorectal cancer patients and their potential as potential biomarkers for predicting chemotherapy response. We also provide a new possible direction for overcoming chemotherapy resistance in colorectal cancer by targeting CAFs-derived exosomes.

Methionine Metabolism Dictates PCSK9 Expression and Antitumor Potency of PD-1 Blockade in MSS Colorectal Cancer

Nutrient metabolisms are vitally interrelated to cancer progression and immunotherapy. However, the mechanisms by which nutrient metabolisms interact to remodel immune surveillance within the tumor microenvironment remain largely unexplored. Here it is demonstrated that methionine restriction inhibits the expression of proprotein convertase subtilisin/kexin type 9 (PCSK9), a key regulator of cholesterol homeostasis and a potential target for cancer immunotherapy, in colorectal cancer (CRC) but not in the liver. Mechanistically, methionine is catabolized to S-adenosylmethionine (SAM), promoting mRNA transcription of PCSK9 through increased DNA methyltransferase 1 (DNMT1)-mediated DNA methylation and suppression of sirtuin 6 (SIRT6) expression. Furthermore, both PCSK9 inhibition and dietary methionine restriction (DMR) potentiate PD-1 blockade therapy and foster the infiltration of CD8+ T cells in Colon 26 tumor-bearing mice-a proficient mismatch repair (pMMR)/microsatellite stable (MSS) CRC model that exhibits limited response to anti-PD-1 therapy. Moreover, combining 5-fluorouracil (5-FU) chemotherapy with PCSK9 inhibition and PD-1 blockade further augments therapeutic efficacy for MSS CRC. The findings establish a mechanistic link between amino acid metabolism and cholesterol metabolism within the tumor microenvironment where tumor cells sense methionine to regulate PCSK9 expression, highlighting promising combination therapeutic strategies that may greatly benefit MSS CRC patients.

Patient-derived mini-colons enable long-term modeling of tumor-microenvironment complexity

Existing organoid models fall short of fully capturing the complexity of cancer because they lack sufficient multicellular diversity, tissue-level organization, biological durability and experimental flexibility. Thus, many multifactorial cancer processes, especially those involving the tumor microenvironment, are difficult to study ex vivo. To overcome these limitations, we herein implemented tissue-engineering and microfabrication technologies to develop topobiologically complex, patient-specific cancer avatars. Focusing on colorectal cancer, we generated miniature tissues consisting of long-lived gut-shaped human colon epithelia ('mini-colons') that stably integrate cancer cells and their native tumor microenvironment in a format optimized for real-time, high-resolution evaluation of cellular dynamics. We demonstrate the potential of this system through several applications: a comprehensive evaluation of drug effectivity, toxicity and resistance in anticancer therapies; the discovery of a mechanism triggered by cancer-associated fibroblasts that drives cancer invasion; and the identification of immunomodulatory interactions among different components of the tumor microenvironment. Similar approaches should be feasible for diverse tumor types.

RBM15-mediated metabolic reprogramming boosts immune response in colorectal cancer

Introduction

Immune checkpoint blockade (ICB) therapy has shown promise in treating advanced colorectal cancer, particularly in patients with microsatellite instability-high (MSI-H) tumors. However, only a subset of these patients responds favorably, highlighting the need for strategies to improve immunotherapy efficacy.

Methods

To identify potential regulators of immunotherapy response, we conducted a comprehensive analysis of colorectal cancer datasets from The Cancer Genome Atlas (TCGA). We performed multi-omics analyses and functional assays in both human and murine colorectal cancer cell lines. Additionally, we evaluated tumor growth and immune cell infiltration using syngeneic mouse models.

Results

Our analysis revealed that RNA binding motif protein 15 (RBM15) is highly expressed in colorectal cancer and correlates with poor patient prognosis. Functional studies demonstrated that RBM15 loss led to increased expression of fumarate hydratase (FH). This led to decreased levels of fumarate, a metabolite known to suppress anti-tumor immune responses. In vivo, RBM15 depletion significantly delayed tumor progression and enhanced CD8⁺ T cell infiltration and activation in the tumor microenvironment.

Discussion

These findings identify RBM15 as a negative regulator of anti-tumor immunity in colorectal cancer. Targeting RBM15 may represent a novel strategy to boost immune responsiveness and improve outcomes for patients undergoing immunotherapy.

Inhibition of MBTPS1 enhances antitumor immunity and potentiates anti-PD-1 immunotherapy

Despite advances in cancer immunotherapy, colorectal cancer patients exhibit limited therapeutic responses. Therefore, the exploration of strategies combining immunotherapy with adjuvant approaches to enhance adaptive immune responses is in demand. Here, we perform a customized in vivo CRISPR-Cas9 screen to target genes encoding membrane and secreted proteins in CRC mouse models with different immune characteristics. We observe that loss of membrane-bound transcription factor site-1 protease (MBTPS1) in tumor cells enhances antitumor immunity and potentiates anti-PD-1 therapy. Mechanistic studies reveal that tumor cell-intrinsic MBTPS1 competes with USP13 for binding to STAT1, thereby disrupting the USP13-dependent deubiquitination-mediated STAT1 stabilization. The upregulated STAT1-transcribed chemokines including CXCL9, CXCL10, and CXCL11, promote CXCR3+CD8+ T cell infiltration. Notably, the regulatory role of MBTPS1 in antitumor immunity operates independently of its classic function in cleaving membrane-bound transcription factors. Collectively, our results provide a theoretical basis for MBTPS1 as a potential immunotherapy target.

Nuclear mitochondrial acetyl-CoA acetyltransferase 1 orchestrates natural killer cell-dependent antitumor immunity in colorectal cancer

Tumor metabolism often interferes with the immune microenvironment. Although natural killer (NK) cells play pivotal roles in antitumor immunity, the connection between NK cells and tumor metabolism remains unclear. Our systematic analysis of multiomics data and survival data from colorectal cancer (CRC) patients uncovered a novel association between mitochondrial acetyl-CoA acetyltransferase 1 (ACAT1) and NK cell infiltration that influences disease progression. ACAT1, a metabolic enzyme involved in reversible conversion of acetoacetyl-CoA to two molecules of acetyl-CoA, exhibits nuclear protein acetylation activity through its translocation. Under immune stimulation, mitochondrial ACAT1 can be phosphorylated at serine 60 (S60) and enters the nucleus; however, this process is hindered in nutrient-poor tumor microenvironments. Nuclear ACAT1 directly acetylates lysine 146 of p50 (NFKB1), attenuating its DNA binding and transcriptional repression activity and thereby increasing the expression of immune-related factors, which in turn promotes NK cell recruitment and activation to suppress colorectal cancer growth. Furthermore, significant associations are found among low nuclear ACAT1 levels, decreased S60 phosphorylation, and reduced NK cell infiltration, as well as poor prognosis in CRC. Our findings reveal an unexpected function of ACAT1 as a nuclear acetyltransferase and elucidate its role in NK cell-dependent antitumor immunity through p50 acetylation.

Lymphovascular invasion affects prognosis of colorectal cancer liver metastasis underwent primary resection: a propensity score matching analysis

BACKGROUND

Lymphovascular invasion (LVI) is associated with poor prognosis in a variety of malignancies; however, its prognostic value has not been fully defined in patients with colorectal cancer with liver metastases (CRCLM). The aim of this study was to investigate the impact of LVI on long-term postoperative recurrence and survival in patients with CRCLM.

METHODS

Clinicopathologic data were retrospectively collected from patients who underwent primary resection for CRCLM at Wuhan Union Hospital from 2013 to 2018. To reduce potential confounders and selection bias, we used propensity score matching (PSM) to compare the clinicopathologic characteristics and long-term prognostic outcomes of patients in the LVI (+) and LVI (-) groups. Cox unifactorial and multifactorial analyses were used to screen relevant factors affecting patient prognosis, and Kaplan-Meier curves were plotted to compare differences in patient overall survival (OS) and disease-free survival (DFS). The predictive power of independent factors on patients' long-term prognosis was assessed using receiver operating characteristic ROC) curves and area under the curve (AUC).

RESULTS

After PSM, 230 patients were enrolled in the study (n = 115 per group). Multifactorial analysis revealed that LVI was an independent prognostic factor for OS and DFS (hazard ratio [HR], 1.424; 95% confidence interval [CI], 1.004-2.022; P = 0.048 and HR, 1.452; 95% CI, 1.020-2.069; p = 0.039, respectively). In the LVI (-) group, postoperative chemotherapy did not significantly improve OS or DFS; however, in the LVI (+) group, those who received chemotherapy had significantly improved OS (HR: 1.593, 95% CI: 1.187 - 2.571; P = 0.044) and DFS (HR: 1.503, 95% CI. 1.033 - 2.422; P = 0.045) compared with patients not treated with chemotherapy. In the LVI (+) group, the AUC for the OS AUROC curves was more favorable compared with after PSM (AUC at 3 years: 0.786 vs. 0.903; AUC at 5 years: 0.744 vs. 0.889). For DFS, the area under the AUROC curve was also better in the LVI (+) subgroup compared with after PSM (AUC at 3 years: 0.825 vs. 0.874; AUC at 5 years: 0.839 vs. 0.863).

CONCLUSIONS

LVI may significantly impact long-term survival and prognosis in patients with CRCLM undergoing primary resection, potentially serving as an independent prognostic factor for OS and DFS. Additionally, postoperative chemotherapy appears to significantly improve the long-term prognosis of patients with LVI (+).

Insights from the bottom-up development of LGR5-targeting immunotherapeutics

Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5), a transcriptional target gene of the Wnt signalling pathway, is overexpressed in multiple cancers, including colorectal cancer (CRC), hepatocellular carcinoma (HCC) and pre-B acute lymphoblastic leukaemia (pre-B ALL) and has emerged as a promising therapeutic target. Here, we reflect on the bottom-up development of a novel α-LGR5 therapeutic antibody we have recently reported, into a palette of LGR5-targeting immunotherapeutic modalities: antibody-drug conjugates (ADCs), bispecific T cell engagers (bispecific engagers), and chimeric antigen receptor (CAR) T cells. The α-LGR5 antibody is highly specific and accurately detects LGR5 protein expression levels, enabling its use as a prognostic biomarker for identifying LGR5+ tumour types. Preclinical studies road-testing the various α-LGR5-based modalities established potent and safe elimination of LGR5-expressing cancer cells in vitro and efficacy in a mouse model of human cancer in vivo. In this review, we discuss the utility of our antibody as the building block for a novel set of immunotherapeutics and highlight the importance of matching specific α-LGR5-based therapeutic modalities to individual tumour type and patient characteristics.

Self-Assembled Glycopeptide as a Biocompatible mRNA Vaccine Platform Elicits Robust Antitumor Immunity

Since the emergence of the COVID-19 pandemic, mRNA vaccines have garnered significant attention. Delivery systems affect the effectiveness of mRNA vaccines, yet there remains a scarcity of vectors that can achieve safe and efficient delivery of mRNA. We took advantage of self-assembled glycopeptides (SAPs) to develop a vector named Man-MPm, which was coupled with mannose and manganese ions to achieve lymph node targeting and STING pathway activation. The Man-MPm-based mRNA vaccine exhibited high biosafety across various administration routes, eliciting robust antigen-specific immune responses within lymph nodes. Due to the elevated antitumor immunity, Man-MPm significantly suppressed tumor growth and extended the survival period of mice in melanoma prevention and treatment models as well as in a colon cancer model. Our findings show that Man-MPm addresses the challenges to safety and effectiveness associated with mRNA delivery by incorporating a lymph node-targeting ligand and a STING pathway agonist onto highly biocompatible SAP, and Man-MPm holds great potential for developing mRNA tumor vaccines.

CCT8 drives colorectal cancer progression via the RPL4-MDM2-p53 axis and immune modulation

PURPOSE

Colorectal cancer (CRC) ranks high in global mortality, emphasizing the need for effective interventions. The aim of the research is to elucidate the oncogenic role of CCT8 in CRC and its interaction with RPL4 in the RPL4-MDM2-p53 axis.

METHODS

TIMER 2.0, TCGA, and GTEx databases were used to analyze CCT8 expression patterns in CRC. Immunohistochemistry was performed to examine CCT8 distribution in CRC tissues and adjacent non-tumor tissues. Functional assays, including CCK-8, transwell, wound-healing, and flow cytometry, were conducted using DLD-1 and HCT116 cell lines to assess the effects of CCT8 on cell proliferation, migration, invasion, and apoptosis. Gene set enrichment analysis, protein-protein interaction network analysis, and co-immunoprecipitation were performed to explore the interaction between CCT8 and RPL4 and their role in the RPL4-MDM2-p53 pathway. Additionally, gene set variation analysis was applied to investigate the relationship between CCT8/RPL4 expression and immune infiltration patterns in CRC.

RESULTS

CCT8 was significantly upregulated in CRC and associated with tumor progression. Mechanistically, CCT8 potentially synergizes with RPL4 concluded from their positive correlation and similar immune infiltration patterns, influencing the RPL4-MDM2-p53 axis and contributing to p53 ubiquitination and degradation.

CONCLUSION

These findings underscore the oncogenic significance of CCT8 in CRC and shed light on its molecular mechanisms, paving the way for potential therapeutic applications.

Construction of a Prognostic Model based on CSC-related Genes in Patients with Colorectal Cancer

Colorectal cancer (CRC) is one of the most common and deadly malignancies. Lack of efficient biomarkers for prognosis has limited the improvement of survival outcome in patients with CRC. Numerous studies have demonstrated the important roles of cancer stem cells (CSCs) in both treatment resistance and disease recurrence of CRC. Thus, the current study aims to construct a prognostic model based on expression level of CSC-related genes for precise molecular subtyping of CRC patients with different prognoses, TME infiltration patterns and therapeutic responses. The RNA sequencing data and clinical information were obtained from UCSC Xena database, followed by identification of differential expressed genes, univariate Cox regression, and LASSO regression to identify prognostic CSC-related genes and construct a novel prognostic risk scoring model consisting of 21 CSC-related genes. The patients in high-risk group suffered poor survival outcome (P<0.0001). Moreover, the performance of CSC-related prognostic model was validated in individual GEO datasets including GSE41258 and GSE39582 (P<0.05). Furthermore, patients with high-risk score exhibited lower response rate to immune checkpoint inhibitors as compared to those in low-risk group (17.4% vs. 28.2%), indicating the potential of CSC-related prognostic model to predict the immunotherapy response. Collectively, our findings provide an effective model to predict the immunotherapy response and survival outcome in patients with CRC.

Safety, efficacy, and cost-effectiveness evaluation of systemic treatments for refractory colorectal cancer: a systematic review and modeling study

OBJECTIVES

To conduct pooled estimates and comparative evaluations of safety and efficacy, alongside cost-effectiveness and value-based pricing analyses, for systemic treatments recommended by the National Comprehensive Cancer Network in refractory colorectal cancer.

METHODS

A comprehensive search for related randomized controlled trials was conducted on PubMed, EMBASE, the Cochrane Library, and ClinicalTrials.gov. Safety was evaluated by aggregating treatment-related adverse events (TRAEs) and performing Bayesian network meta-analysis (NMA) for indirect comparisons. Pooled survival estimates of overall survival (OS) and progression-free survival (PFS) were conducted to assess treatment efficacy. For NMA of OS and PFS, time-variant fractional polynomial models were employed as the primary analysis, with Cox proportional hazards models used for result validation. Economic evaluations were performed using partitioned survival models from the US public sector perspective. Clinical parameters were sourced from meta-analyses; cost parameters included drug treatment, follow-up and administration, end-of-life care, and adverse event management expenses, which were obtained from the Federal Supply Schedule, public databases or published literature. Utility values were sourced from the CORRECT trial. Price simulations were also conducted. Robustness of results was confirmed by sensitivity and scenario analyses RESULTS: We included nine studies comprising 3,978 patients and incorporating six treatments recommended by NCCN, including best supportive care (BSC), regorafenib, regorafenib dose optimization (REDo), trifluridine/tipiracil (TAS-102), TAS-102 with bevacizumab (TAS-BEV), and fruquintinib. Targeted treatments increased serious TRAEs and grade 3 + TRAEs compared to BSC. However, no significant safety differences were found among the targeted therapies. Regarding efficacy, REDo led in median OS, while fruquintinib led in median PFS. NMA indicated that TAS-BEV had the greatest PFS and OS survival benefit, followed by fruquintinib and REDo. Cost-effectiveness analysis favored BSC as the least expensive and the most cost-effective profile. TAS-BEV had the greatest effectiveness, with TAS-102 being the most cost-effective among targeted therapies. For cost-effectiveness against BSC, the price reductions of TAS-102, fruquintinib, REDoS, regorafenib, and TAS-BEV were 39%, 24%, 14%, 8%, and 7%, respectively.

CONCLUSIONS

Targeted therapies have comparable safety; TAS-BEV is highly effective, TAS-102 is the top cost-effective targeted therapy. Treatment choice should balance individual patient needs with safety, efficacy, and cost.

Exploring the Role of Cellular Interactions in the Colorectal Cancer Microenvironment

Colorectal cancer (CRC) stands as one of the tumors with globally high incidence and mortality rates. In recent years, researchers have extensively explored the role of the tumor immune microenvironment (TME) in CRC, highlighting the crucial influence of immune cell populations in driving tumor progression and shaping therapeutic outcomes. The TME encompasses an array of cellular and noncellular constituents, spanning tumor cells, immune cells, myeloid cells, and tumor-associated fibroblasts, among others. However, the cellular composition within the TME is highly dynamic, evolving throughout different stages of tumor progression. These shifts in cell subpopulation proportions lead to a gradual transition in the immune response, shifting from an early antitumor growth to a late-stage environment that supports tumor survival. Therefore, it is crucial to further investigate and understand the complex interactions among the various cell populations within the TME. In this review, we explore the key cellular components of varying origins, subpopulations with shared origins, and noncellular elements within the CRC TME, examining their interconnections and critical considerations for developing personalized and precise immunotherapy strategies.

Differential antibody response to EBV proteome following EBVST immunotherapy in EBV-associated lymphomas

ABSTRACT

Epstein-Barr virus (EBV) is associated with a diverse range of lymphomas. EBV-specific T-cell (EBVST) infusions have shown promise in safety and clinical effectiveness in treating EBV-associated lymphomas; however, not all patients respond to T-cell immunotherapies. To identify EBV antigen-specific antibody responses associated with clinical outcomes, we comprehensively characterized antibody responses to the complete EBV proteome using a custom protein microarray in 56 patients with EBV-associated lymphoma who received EBVST infusions in phase 1 clinical trials. Responders (nonprogressors) and nonresponders (progressors) had distinct antibody profiles against EBV. Twenty-five immunoglobulin G (IgG) antibodies were significantly elevated in higher levels in nonresponders than in responders at 3 months after EBVST infusion. Ten of these remained significant after adjustment for sex, age, and cancer type, including LMP2A (4 variants), BGRF1/BDRF1 (2 variants), LMP1, BKRF2, BKRF4, and BALF5. Random forest analysis identified these 10 IgG antibodies as key predictors of clinical response. Paired analyses using blood samples collected at both before infusion and 3 months after EBVST infusion indicated an increase in the mean antibody level for 6 other anti-EBV antibodies (IgG [BGLF2, LF1, and BGLF3]; IgA [BGLF3, BALF2, and BBLF2/3) in nonresponders. Overall, our findings suggest that these EBV-directed antibodies as potential serological markers for predicting clinical responses to EBVST infusions and as therapeutic targets for immunotherapy in EBV-positive lymphomas. These trials were registered at www.clinicaltrials.gov as #NCT01555892 (Cytotoxic T-Lymphocytes for EBV-positive Lymphoma [GRALE]), #NCT02973113 (Nivolumab With Epstein Barr Virus Specific T Cells [EBVSTS], Relapsed/Refractory EBV Positive Lymphoma [PREVALE]), and #NCT02287311 (Most Closely Matched 3rd Party Rapidly Generated LMP, BARF1, and EBNA1 Specific CTL, EBV-Positive Lymphoma [MABEL]).

Robotic-assisted colorectal surgery in colorectal cancer management: a narrative review of clinical efficacy and multidisciplinary integration

Colorectal cancer (CRC) remains a formidable global health challenge, ranking among the most prevalent malignancies and a principal contributor to cancer-associated mortality. While traditional open surgery has historically been the cornerstone of CRC treatment, the advent of minimally invasive techniques, particularly robotic-assisted colorectal surgery (RACS), has garnered significant momentum owing to technological advancements in the field. Robotic platforms, exemplified by the da Vinci Surgical System, offer superior three-dimensional visualization, enhanced dexterity, and heightened precision, yielding improved perioperative outcomes, particularly in anatomically intricate regions such as the pelvis. This review provides a critical appraisal of the current landscape of RACS, emphasizing its superiority over conventional open and laparoscopic approaches. The increased control and precision afforded by robotic surgery have been shown to optimize outcomes in complex procedures such as total mesorectal excision, with evidence indicating reduced intraoperative blood loss, shortened hospital stays, and improved functional recovery. Nonetheless, challenges persist, including absence of haptic feedback, prohibitive costs, and steep learning curve associated with robotic systems. Despite these limitations, RACS has demonstrated considerable promise in sphincter-preserving and function-preserving procedures, ultimately enhancing postoperative quality of life. Beyond the surgical field, this review also investigates the integration of robotic surgery within multidisciplinary treatment strategies for CRC, particularly in the context of locally advanced rectal cancer. The combination of robotic techniques with total neoadjuvant therapy and immunotherapy-especially in tumors characterized by mismatch repair deficiency or high microsatellite instability has shown notable clinical efficacy. Furthermore, emerging personalized therapeutic approaches, including immunotherapies and targeted chemotherapeutic agents, emphasize the transformative potential of RACS in delivering superior oncologic outcomes. Looking towards the future, innovations in robotic platforms, including intraoperative imaging, artificial intelligence, and augmented reality, herald new possibilities for further enhancing the precision and efficacy of colorectal surgeries. The standardization of RACS protocols, alongside ongoing training and robust clinical research, will be critical to fully realizing the benefits of these advancements across diverse clinical settings. By incorporating cutting-edge technologies and personalized treatment methods, robotic-assisted surgery is prepared to become a cornerstone in future of CRC management, with the potential to significantly improve both survival outcomes and patient quality of life.

The potential role of PD-1/PD-L1 small molecule inhibitors in colorectal cancer with different mechanisms of action

Colorectal cancer (CRC) remains one of the leading causes of cancer-related death worldwide, with increasing incidence in younger ages highlighting the need for new or alternative therapy, of which is immune checkpoint inhibitors. Antibody-based immune checkpoint inhibitors targeting the interaction between programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) have revolutionized cancer treatment, including CRC. However, the low response rate in CRC highlights the need for additional research and innovative therapies. Small molecule inhibitors have risen as another strategy worth exploring, considering their potential to target a wide array of PD-1/PD-L1-related pathways. This review focuses on the potential of small molecule inhibitors targeting the PD-1/PD-L1 axis in CRC. Exploring various classes of small molecule inhibitors, including those that directly block the PD-1/PD-L1 interaction and others that target upstream regulators or downstream signaling pathways involved in PD-1/PD-L1-mediated immune suppression. Additionally, modulation of post-transcriptional and post-translational processes, thereby influencing the expression, stability, or localization of PD-1/PD-L1 proteins to enhance antitumor immunity, provides a multifaceted treatment approach. By disrupting these pathways, these inhibitors can restore immune system activity against tumor cells, offering new hope for overcoming resistance and improving outcomes in CRC patients who do not respond to conventional immune checkpoint inhibitors (ICIs). Integrating these small molecules into CRC treatment strategies could represent a promising advancement in the battle against the challenging disease.

HOXC6 promotes the metastasis of MSI-H CRC by interacting with M2 macrophages and inducing effector T cell exhaustion

We previously discovered that HOXC6 was the most significantly upregulated gene in right-sided colon cancer compared to left-sided colon cancer according to our previous study; however, the role of HOXC6 in microsatellite instability-high (MSI-H) tumors remains poorly understood. Here, multiple public datasets, and in-house cohorts were used to analyze the differential expression and prognostic role of HOXC6 in colorectal cancer (CRC). Immunohistochemistry and immunofluorescence were performed to evaluate the correlation between HOXC6 expression and M2 macrophage infiltration. CCK8 and Transwell assays were used to evaluate the proliferation and migration of tumor cells in vitro. BALB/c nude mice were utilized to construct a humanized immune system model to evaluate the efficacy of ruxolitinib in vivo. We found that HOXC6 was overexpressed in MSI-H CRC and associated with a poor prognosis. Upregulation of CCL2 by HOXC6 increased M2 macrophage infiltration. IL6 secreted by M2 macrophages induced the epithelial-mesenchymal transition of tumor cells by upregulating HOXC6. M2 macrophages promoted effector T cell exhaustion by downregulating 4-1BB. Thus, inhibition of the IL6/JAK pathway in M2 macrophages restored 4-1BB expression and T-cell cytotoxicity offering a promising therapeutic target for the treatment of HOXC6-overexpressing MSI-H CRC.

Evaluation of immune-checkpoint molecules in dMMR/pMMR colorectal cancer by multiplex immunohistochemistry

PURPOSE

Colorectal cancer is the most common malignancy worldwide. A number of pathological and molecular genetic criteria are currently used as predictors of the disease. They include assessment of MMR deficiency or MSI/MSS status, which among others, determine the immunogenicity of the tumor. In this regard, the evaluation of PD-L1, CTLA-4, and LAG-3 immune checkpoint molecules in different tumor compartments according to MMR status deserves special attention.

METHODS

Multiplex immunohistochemistry was used to evaluate the expression of immune checkpoint molecules in the tumor core and at the invasive margin.

RESULTS

Data analysis showed the predominance of PD-L1 (p = 0.011), CTLA-4 (p = 0.004), and LAG-3 (p = 0.013) expression at the invasive margin of dMMR carcinomas compared to pMMR samples. Quantitative analysis of TILs population in the tumor core and at the invasive margin allowed establishment of the predominance of CD3+ and CD8+ lymphocytes at the invasive margin of dMMR carcinomas. Study of the CD163+ macrophages population in the same tumor compartments revealed the predominance of the studied TAMs in the core and at the invasive margin of dMMR carcinomas and the predominance of CD163+ macrophages with PD-L1-phenotype in the tumor stroma.

CONCLUSION

This study revealed a significant predominance of PD-L1, CTLA-4, LAG-3, and CD 3+ ,CD8+ lymphocytes in dMMR colorectal carcinomas. Further research on the immune landscape in different tumor compartments will likely have high prognostic value for CRC patients, as it might expand the criteria for prescribing immunotherapy.