Tumor-Infiltrating Lymphocytes in Colorectal Cancer: The Fundamental Indication and Application on Immunotherapy

Application of single-cell sequencing in the study of immune cell infiltration in inflammatory bowel disease and colorectal cancer

The rapid advancement of single-cell sequencing (SCS) technology has provided new insights into the relationship between inflammatory bowel disease (IBD) and colorectal cancer (CRC). This technique allows for detailed cellular analysis, enabling researchers to uncover the infiltration patterns of immune cells within the gut microenvironment and their roles in disease progression. This review summarizes significant research findings on the interplay between IBD and CRC, the characteristics of immune cell infiltration, and potential therapeutic targets identified through SCS. The aim is to offer references for future clinical studies and treatment strategies in this field.

Assessment of compartment-specific CD103-positive cells for prognosis prediction of colorectal cancer

BACKGROUND

CD103+ tissue-resident memory T cells was detected in various solid malignancies, like colorectal cancer (CRC), and associated with improved survival. However, clinical significance of CD103+ cells in specific intratumor compartment remains unclear.

METHODS

The abundance and distribution of CD103+ cells were assessed using immunohistochemistry and quantified separately for 3 compartments, including intraepithelial compartments at center of tumor (CT-IEL), stromal compartments at center of tumor (CT-ST) and invasive margin (IM) in a cohort of 224 CRC patients under radical surgery and correlated with outcome. Findings in each compartment were then validated in an external validation cohort comprising 294 CRC patients.

RESULTS

Elevated density of CD103+ cells infiltration in the CT-IEL, CT-ST or IM compartment was correlated with favorable survival in both the initial discovery cohort and subsequent validation cohort. Notably, abundant CD103+ cells located in the CT-IEL compartment was remained an independent prognostic indicator for CRC patients by multivariant analysis. Characterization study showed that intraepithelial CD103+ cells were predominantly single positive CD8 T cells. Conversely, CD103+ cells exhibited a heterogeneous population comprising CD103+CD8+ cells, CD103+CD4+ cells, and nonconventional CD103+CD4+CD8+ cells in the CT-ST and IM compartments. Finally, a CD103 score was generated comprising abundance of CD103+ cells in the 3 compartments. This score had the highest relative contribution to the risk of all clinical parameters for prognosis in both cohorts.

CONCLUSION

This study supported a phenotypic heterogeneity of CD103+ cells in CRC, and provided a reliable estimate of the risk of death and recurrence in CRC patients based on combined analysis of CD103+ cells within 3 intratumor compartments.

New Frontiers of Biomarkers in Metastatic Colorectal Cancer: Potential and Critical Issues

Metastatic colorectal cancer (mCRC) remains a major cause of cancer-related mortality worldwide and requires the development of new biomarkers to improve patient management. Traditional markers, such as RAS mutations and microsatellite instability (MSI), have revolutionized therapeutic decisions, but emerging evidence underlines the importance of integrating multi-omics sciences for a deeper understanding of tumor biology and therapeutic resistance. Although these omics technologies hold great promise for the advancement of precision oncology, significant challenges remain. However, the integration of multi-omics data is opening the way to more accurate diagnostics, personalized therapies, and improved outcomes for mCRC patients. This review provides an in-depth description of the various omics sciences and explores their advantages and critical issues.

Dipeptidase-1-knockout mice develop invasive tumors with features of microsatellite-unstable colorectal cancer

Dipeptidase-1 (DPEP1) is highly upregulated in colorectal cancer (CRC), with its enzymatic function linked to invasion and metastasis. More recently, DPEP1 was found to serve as a receptor for neutrophils when expressed by activated endothelial cells. It is unknown whether neutrophils bind to DPEP1-expressing CRC cells and whether this impacts features of CRC. Neutrophils have been shown to be tumor promoting in cancers including CRC, where they act to exclude CD8+ T cells. Herein, we show that neutrophils bind DPEP1-expressing CRC cells. In addition, DPEP1 is preferentially expressed in microsatellite-stable (MSS) CRCs, in which there are a paucity of CD8+ T cells, whereas DPEP1 is negatively correlated with microsatellite-unstable (MSI-H) CRCs, which are T cell rich and are more responsive to immunotherapy. Remarkably, carcinogen-treated Dpep1-null mice develop multiple, large, plaque-like, locally invasive adenocarcinomas and squamous cell cancers in the distal colon. These adenocarcinomas exhibit a marked reduction in neutrophils and an influx CD8+ T cells, along with reduced expression of mismatch repair proteins, consistent with features of MSI-H CRC. These results establish DPEP1's importance in maintaining MSS CRC and its ability to shape the tumor microenvironment.

Curcumin exerts anti-tumor activity in colorectal cancer via gut microbiota-mediated CD8+ T Cell tumor infiltration and ferroptosis

Colorectal cancer (CRC), as a high-incidence malignancy, continues to present significant challenges in prevention, screening, and treatment. Curcumin (Cur) exhibits notable anti-inflammatory and anticancer properties. Despite its poor solubility in water and low bioavailability, high concentrations of Cur are detected in the gastrointestinal tract after oral administration, suggesting that it may directly interact with the gut microbiota and exert regulatory effects. This study aims to explore the mechanisms by which Cur improves CRC by modulating gut microbiota. Firstly, we evaluated the effect of Cur on CRC cell viability in vitro using the MTT assay, and the results showed a significant inhibitory effect on CRC cell growth. The IC50 values for Cur in CT26 and RKO cells were 23.52 μM, 16.11 μM, and 13.62 μM at 24, 48, and 72 hours, respectively, and 26.3 μM, 16.52 μM, and 14.22 μM at 24, 48, and 72 hours, respectively. Cur induced apoptosis and caused G2 phase cell cycle arrest in tumor cells. Subsequently, we established a CRC mouse model. Oral administration of Cur at 15 mg kg-1 and 30 mg kg-1 inhibited CRC progression, as evidenced by reduced tumor volume, histological analysis, immunohistochemistry, and an increased number of CD8+ T cells infiltrating the tumors. Ferroptosis in tumor cells was also observed. Cur partially restored the gut microbiota of CRC mice, altering the abundance and diversity of the gut microbiota and affecting serum metabolite distribution, with significant increases in the abundance of SCFA-producing microbes such as Lactobacillus and Kineothrix. To verify causality, we designed a fecal microbiota transplantation (FMT) experiment. Compared with CRC mice, the fecal microbiota from Cur-treated mice significantly alleviated CRC symptoms, including slowed tumor growth, enhanced CD8+ T cell tumor infiltration, and induced ferroptosis in tumor cells. Additionally, when gut microbiota was depleted with antibiotics, Cur's antitumor effects disappeared, suggesting that Cur mitigates CRC in a gut microbiota-dependent manner. These findings provide new insights into the mechanisms underlying CRC and propose novel therapeutic interventions, emphasizing the interaction between gut microbiota and immune responses within the tumor immune microenvironment (TIME).

Outcomes of tumor-infiltrating lymphocyte therapy in solid tumours - A systematic review and meta analysis

BACKGROUND

Tumor-infiltrating lymphocyte (TIL) treatment is an individualized method of treating different types of solid tumors by using the immune system of the body to target and destroy cancer cells. Although its usefulness has been shown in certain diseases, such as ovarian cancer and melanoma, research is still being done to see whether it is also beneficial against a wider variety of solid tumors.

AIM

To methodically assess the safety, effectiveness, and clinical results of TIL therapy for various solid tumors.

METHODOLOGY

A thorough search in various databases produced 218 papers on TIL treatment for various solid tumors (2018-2024). Nine of the ten papers that satisfied the requirements for inclusion in the quantitative analysis were also included in the systematic review. Two reviewers separately extracted the data and evaluated it. The Newcastle-Ottawa Scale and the Cochrane Risk of Bias tool were used to evaluate the quality of the studies, and the I2 statistic in the meta-analysis was used to measure heterogeneity.

RESULTS

Numerous studies that looked at the effectiveness of TIL treatment in different types of cancer showed different results. In NSCLC and melanoma, higher CD8+/CD4+ TIL ratios were associated with improved outcomes; in advanced melanoma, TIL therapy was superior to ipilimumab. Response rates differed, with NSCLC showing up at 23.1 % and melanoma up to 53.3 %. Most studies were of good quality and is confirmed by the Newcastle-Ottawa Scale, while some had problems with follow-up. The results' dependability was confirmed by the ROBINS-I and ROB2 tools, which showed low to moderate bias risk.

CONCLUSION

According to the study's findings, TIL therapy is effective in treating solid tumors, especially melanoma, but its results vary according to the kind of cancer as well as tumour microenvironments. Therefore more research is needed to determine the best course of action.

Genomic landscape of cancer in racially and ethnically diverse populations

Cancer incidence and mortality rates can vary widely among different racial and ethnic groups, attributed to a complex interplay of genetic, environmental and social factors. Recently, substantial progress has been made in investigating hereditary genetic risk factors and in characterizing tumour genomes. However, most research has been conducted in individuals of European ancestries and, increasingly, in individuals of Asian ancestries. The study of germline and somatic genetics in cancer across racial and ethnic groups using omics technologies offers opportunities to identify similarities and differences in both heritable traits and the molecular features of cancer genomes. An improved understanding of population-specific cancer genomics, as well as translation of those findings across populations, will help reduce cancer disparities and ensure that personalized medicine and public health approaches are equitable across racial and ethnic groups.

Combination therapy with immune checkpoint inhibitors in colorectal cancer: Challenges, resistance mechanisms, and the role of microbiota

Colorectal cancer (CRC) is still one of the leading causes of cancer deaths worldwide. Even though there has been progress in cancer immunotherapy, the results of applying immune checkpoint inhibitors (ICIs) have been unsatisfactory, especially in microsatellite stable (MSS) CRC. Single-agent ICIs that target programmed cell death-1 (PD-1)/ PD-L1, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), T cell Ig- and mucin-domain-containing molecule-3 (TIM-3), and lymphocyte activation gene (LAG)-3 have emerged as having specific benefits. However, many primary and secondary resistance mechanisms are available in the tumor microenvironment (TME) that prevent it from happening. Combination strategies, such as the use of anti-PD-1 and anti-CTLA-4, can be effective in overcoming these resistance pathways, but toxicities remain a significant concern. Moreover, ICIs have been integrated with various treatment modalities, including chemotherapy, radiotherapy, antibiotics, virotherapy, polyadenosine diphosphate-ribose polymerase (PARP) inhibitors, and heat shock protein 90 (HSP90) inhibitors. The outcomes observed in both preclinical and clinical settings have been encouraging. Interestingly, manipulating gut microbiota via fecal microbiota transplantation (FMT) has been identified as a new strategy to increase the efficacy of immunotherapy in CRC patients. Therefore, integrating ICIs with other treatment approaches holds promise in enhancing the prognosis of CRC patients. This review focuses on the unmet need for new biomarkers to select patients for combination therapies and the ongoing work to overcome resistance and immune checkpoint blockade.

CCR9 shapes the immune microenvironment of colorectal cancer modulating the balance between intratumoral CD8+ T cell and FoxP3+ Helios+ Treg subpopulations

Colorectal cancer (CRC) is the third most common cancer in the world and the second cause of death related to cancer. Regulatory T cell (Treg) infiltration is enriched in several tumor types including CRC and correlates with suppression of the anti-tumor immune response. In the large intestine, thymic Tregs (tTregs Helios+) and peripheral Tregs (pTregs Helios-) coexist and maintain intestinal homeostasis under steady state conditions. The recruitment of Treg cells to the intestine is orchestrated by the CCR9/CCL25 axis, which is potentiated under inflammatory conditions. Interestingly, the balance between cytotoxic CD8+ T cells and Tregs within the tumor microenvironment is critical for antitumor immunity and cancer progression. An elevated CD8+/Treg ratio has been associated with improved clinical outcomes in various cancers, including CRC. Therefore, here we investigate the potential role of chemokine receptor CCR9 on CD8+/Treg ratio and the effect of the recruitment of Treg subpopulations (Helios+ and Helios-) into the tumor microenvironment using the AOM/DSS induced colitis-associated colorectal cancer murine model. Our findings reveal that CCR9 deficiency leads to distinct alterations in the CRC microenvironment, characterized by decreased intratumoral Tregs Helios+. Also, the lack of the receptor leads to an improvement of the antitumor immune response, increasing the CD8+/Treg ratio within the tumor immune infiltrate. These results underscore the importance of CCR9 in shaping the immune microenvironment during CRC development.

Causal association between immune cell phenotypes and colorectal cancer: a two-sample bidirectional Mendelian randomization analysis

BACKGROUND

Colorectal cancer (CRC) remains one of the leading causes of cancer-related death worldwide. Increasing evidence suggests that alterations in the immune system may play a pivotal role in the initiation and progression of CRC. However, the precise causal relationship between specific immune cell phenotypes and CRC remains incompletely understood. Elucidating this connection may unveil novel therapeutic targets for the treatment of CRC.

METHODS

To explore the causal relationship between immune cell phenotypes and CRC, we conducted a comprehensive bidirectional Mendelian randomization (MR) analysis. Genetic variants were utilized as instrumental variables (IVs), with the inverse variance weighting (IVW) method employed to assess the effect of specific immune cell phenotypes on CRC risk. Sensitivity analysis were performed to evaluate the robustness of our findings, while heterogeneity analysis were conducted to minimize the potential impact of pleiotropy.

RESULTS

Our MR analysis revealed potential causal associations between various immune phenotypes and CRC. Specifically, 34 immune cell types were found to be potentially causally associated with colon cancer, while 29 immune cell types showed a potential causal relationship with rectal cancer. Sensitivity analysis further confirmed the robustness of these associations, suggesting that these immune cell phenotypes may play a significant role in the development of CRC.

CONCLUSION

Our study provides evidence for a causal relationship between immune cell phenotypes and CRC. These findings suggest that immune cell characteristics may serve as potential biomarkers for CRC and could represent novel therapeutic targets. However, further experimental research is needed to explore the underlying mechanisms in greater detail and to validate the clinical applicability of these findings.

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.

The single-cell spatial landscape of stage III colorectal cancers

We conducted a spatial analysis of stage III colorectal adenocarcinomas using Hyperion Imaging Mass Cytometry, examining 52 tumors to assess the tumor microenvironment at the single-cell level. This approach identified 10 distinct cell phenotypes in the tumor microenvironment, including stromal and immune cells, with a subset showing a proliferative phenotype. By focusing on spatial neighborhood interactions and tissue niches, particularly regions with tumor-infiltrating lymphocytes, we investigated how cellular organization relates to clinicopathological and molecular features such as microsatellite instability (MSI) and recurrence. We determined that microsatellite stable (MSS) colorectal cancers had an increased risk of recurrence if they had the following features: 1) a low level of stromal tumor-infiltrating lymphocytes, and 2) low interactions between CD4 + T cells and stromal cells. Our results point to the utility of spatial single-cell interaction analysis in defining novel features of the tumor immune microenvironments and providing useful clinical cell-related spatial biomarkers.

Antitumor effects of immunotherapy combined with BRAF and MEK inhibitors in BRAF V600E metastatic colorectal cancer

BRAF-mutated colorectal cancer correlates with poor prognosis and limited response to standard treatments. Combining immune checkpoint inhibitors with BRAF/MEK inhibitors shows promise against BRAF-mutant melanoma in both preclinical and clinical trials. Therefore, we hypothesized that the treatment would be effective against BRAF-mutant colorectal cancer. In this study, we assessed the efficacy of combining immune checkpoint inhibitors with BRAF and/or MEK inhibitors in BRAF-mutant colorectal cancers. We treated BRAF V600E colorectal cancer cells HT-29 and SNU-1235 with encorafenib (BRAF inhibitor) and binimetinib (MEK inhibitor) and assessed the degrees of MAPK inhibition, JAK/STAT inhibition, cell viability, apoptosis, and the expression of antigen presenting machinery. We also inoculated HT-29 cells into mice and treated them with an immune checkpoint inhibitor (durvalumab), encorafenib, and binimetinib for 4 weeks. We found that treatment with BRAF inhibitor, MEK inhibitor, or their combination led to significant tumor growth reduction, along with the MAPK and JAK/STAT pathway inhibition, antigen presenting machinery induction, and cytotoxic T cell activation. Our study demonstrates the potential effectiveness of combining immune checkpoint inhibitors with BRAF or MEK inhibitors for BRAF-mutated colorectal cancers.

Prognostic Significance of STK11/LKB1 Expression and Its Role in the Tumor Microenvironment of Colorectal Adenocarcinoma

BACKGROUND/AIM

The loss or mutation of serine-threonine kinase 11/liver kinase B1 (STK11/LKB1) is known to negatively impact prognosis and immunotherapy outcomes in non-small cell lung cancer (NSCLC), and germline mutations in this gene cause gastrointestinal adenocarcinomas in patients with Peutz-Jeghers syndrome (PJS). Although STK11/LKB1 mutations are rare in colorectal cancer, the down-regulation of STK11/LKB1 has been implicated in its tumorigenesis. However, the relationship between STK11/LKB1 expression and the immunosuppressive tumor microenvironment in colorectal cancer remains unclear.

MATERIALS AND METHODS

In this study, we collected tissues from patients with colorectal adenocarcinoma (COAD) and constructed tissue microarrays (TMAs). STK11/LKB1 expression was assessed by immunohistochemistry and quantified by calculating H-scores. We also examined subsets of intratumoral tumor-infiltrating lymphocytes (TILs), including CD45+, CD8+, PD-1+, and CD45RO+ TILs, in these TMAs.

RESULTS

STK11/LKB1 expression was significantly correlated with nodal metastasis. Kaplan-Meier survival analysis demonstrated that low STK11 expression was associated with significantly poorer overall survival (OS), particularly in COAD patients with KRAS mutations. However, STK11/LKB1 expression was not correlated with the presence of intratumoral CD45+, CD8+, PD-1+, or CD45RO+ TILs. Finally, multivariate Cox proportional regression analysis identified STK11/LKB1 expression as an independent prognostic factor in COAD patients.

CONCLUSION

While STK11/LKB1 expression is associated with tumor progression and survival outcomes, there is no evidence that STK11/LKB1 expression influences the infiltration of lymphocytes into the tumor microenvironment.

Tumor-Agnostic Therapies in Practice: Challenges, Innovations, and Future Perspectives

This review comprehensively analyzes the current landscape of tumor-agnostic therapies in oncology. Tumor-agnostic therapies are designed to target specific molecular alterations rather than the primary site of the tumor, representing a shift in cancer treatment. We discuss recent approvals by regulatory agencies such as the FDA and EMA, highlighting therapies that have demonstrated efficacy across multiple cancer types sharing common alterations. We delve into the trial methodologies that underpin these approvals, emphasizing innovative designs such as basket trials and umbrella trials. These methodologies present unique advantages, including increased efficiency in patient recruitment and the ability to assess drug efficacy in diverse populations rapidly. However, they also entail certain challenges, including the need for robust biomarkers and the complexities of regulatory requirements. Moreover, we examine the promising prospects for developing therapies for rare cancers that exhibit common molecular targets typically associated with more prevalent malignancies. By synthesizing these insights, this review underscores the transformative potential of tumor-agnostic therapies in oncology. It offers a pathway for personalized cancer treatment that transcends conventional histology-based classification.

Single-cell spatial immune profiling for precision immunotherapy in Lynch syndrome

Lynch syndrome (LS) is the most common hereditary colorectal cancer (CRC) predisposition syndrome, characterized by a high mutational burden and microsatellite instability-high (MSI-H) tumors. Immunology of LS-associated CRC (LS-CRC) is unique, with significant implications for treatment. Despite well-established knowledge of LS immunology, immunotherapy dose and treatment response can vary significantly based on local tumor immunity and specific germline pathogenic variant of LS genes. This variability necessitates tailored surveillance strategies and new personalised immunotherapy approaches for LS patients. LS-CRC often benefits from immunotherapy due to the distinct tumor microenvironment (TME) and the variety of tumor infiltrating lymphocytes (TILs). This perspective discusses a novel approach of analysing spatial TILs at a single-cell level using tumor whole slide images (WSIs) that accounts for the distinct TME of LS-CRC. By emphasizing the necessity of personalized medicine in hereditary cancer syndromes, the future research and clinical practices that enhance patient outcomes through precision oncology is inspired.

Computational pathology applied to clinical colorectal cancer cohorts identifies immune and endothelial cell spatial patterns predictive of outcome

Colorectal cancer (CRC) is a histologically heterogeneous disease with variable clinical outcome. The role the tumour microenvironment (TME) plays in determining tumour progression is complex and not fully understood. To improve our understanding, it is critical that the TME is studied systematically within clinically annotated patient cohorts with long-term follow-up. Here we studied the TME in three clinical cohorts of metastatic CRC with diverse molecular subtype and treatment history. The MISSONI cohort included cases with microsatellite instability that received immunotherapy (n = 59, 24 months median follow-up). The BRAF cohort included BRAF V600E mutant microsatellite stable (MSS) cancers (n = 141, 24 months median follow-up). The VALENTINO cohort included RAS/RAF WT MSS cases who received chemotherapy and anti-EGFR therapy (n = 175, 32 months median follow-up). Using a Deep learning cell classifier, trained upon >38,000 pathologist annotations, to detect eight cell types within H&E-stained sections of CRC, we quantified the spatial tissue organisation and colocalisation of cell types across these cohorts. We found that the ratio of infiltrating endothelial cells to cancer cells, a possible marker of vascular invasion, was an independent predictor of progression-free survival (PFS) in the BRAF+MISSONI cohort (p = 0.033, HR = 1.44, CI = 1.029-2.01). In the VALENTINO cohort, this pattern was also an independent PFS predictor in TP53 mutant patients (p = 0.009, HR = 0.59, CI = 0.40-0.88). Tumour-infiltrating lymphocytes were an independent predictor of PFS in BRAF+MISSONI (p = 0.016, HR = 0.36, CI = 0.153-0.83). Elevated tumour-infiltrating macrophages were predictive of improved PFS in the MISSONI cohort (p = 0.031). We validated our cell classification using highly multiplexed immunofluorescence for 17 markers applied to the same sections that were analysed by the classifier (n = 26 cases). These findings uncovered important microenvironmental factors that underpin treatment response across and within CRC molecular subtypes, while providing an atlas of the distribution of 180 million cells in 375 clinically annotated CRC patients. © 2025 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

The Impact of Nutritional Status and Tumor-Infiltrating Lymphocytes (CD4+ and CD8+) on Chemotherapy Response in Colorectal Cancer Patients

Introduction

The World Health Organization reports that colorectal cancer (CRC) is the second leading cause of cancer-related mortality globally, with an estimated 1.9 million new cases annually. Tumor-infiltrating lymphocytes (TILs) are frequently associated with colorectal cancer and are believed to play a significant role in the immune response to cancer cells. Regarding chemotherapy responses in patients with colorectal cancer, this study aims to investigate the association between nutritional status and infiltrating lymphocyte counts, specifically CD4+ and CD8+.

Materials and Methods

This prospective observational study analyzed the impact of nutritional status using body mass index (BMI) and TILs levels (CD4+/CD8+) on chemotherapy outcomes in CRC patients treated at a tertiary hospital in West Java, Indonesia, from July 2023 to June 2024.

Results

Thirty-six research subjects were included. Eighteen participants had high levels of TILs CD4+ and CD8+ expression. Nutritional status, age, histological type, tumor site, stage, and metastasis showed no significant correlation with the expression of either CD4+ or CD8+. Nutritional status, levels of CD4+ and CD8+ were significantly associated with chemotherapy responses in CRC patients (p<0.001).

Conclusion

Nutritional status and elevated TIL levels (CD4+/CD8+) positively correlate with better chemotherapy response in CRC patients.

Tumor aggression-defense index-a novel indicator to predicts recurrence and survival in stage II-III colorectal cancer

BACKGROUND

Although the TNM staging system plays a critical role in guiding adjuvant chemotherapy for colorectal cancer (CRC), its precision for risk stratification in stage II and III CRC patients with proficient DNA mismatch repair (pMMR) remains limited. Therefore, precise predictive models and research on postoperative treatments are crucial for enhancing patient survival and improving quality of life.

METHODS

This retrospective study analyzed 1051 pMMR CRC patients who underwent radical resection and were randomly assigned to training (n = 736) and validation (n = 315) groups. Immunohistochemistry and hematoxylin and eosin staining were utilized to evaluate regulatory-Immunoscore (RIS), tertiary lymphoid structures (TLS), and tumor budding (TB). The Tumor Aggression-Defense Index (TADI) was derived through a multi-factor COX regression model. Subgroup analysis demonstrated potential of TADI in guiding personalized adjuvant therapy for stage II and III CRC.

RESULTS

Univariate and multivariate Cox analysis indicated that TADI was an independent prognostic indicator. Among stage II CRC, chemotherapy was significantly correlated with improved recurrence times in individuals with intermediate (95% CI 0.19-0.59, P < 0.001) and high (95% CI 0.36-0.95, P = 0.031) TADI. In stage III CRC receiving adjuvant chemotherapy, a duration of 3 months or longer was notably associated with a prolonged time to recurrence in those with high TADI (95% CI 0.40-0.98, P = 0.041) compared to durations of less than 3 months.

CONCLUSION

The TADI serves as an effective parameter for predicting the survival outcomes of stage I-III pMMR CRC patients and guiding precision treatment strategies.

The characteristics of the tumor immune microenvironment in colorectal cancer with different MSI status and current therapeutic strategies

Colorectal cancer (CRC) remains a significant cause of cancer-related mortality worldwide. Despite advancements in surgery, chemotherapy, and radiotherapy, the effectiveness of these conventional treatments is limited, particularly in advanced cases. Therefore, transition to novel treatment is urgently needed. Immunotherapy, especially immune checkpoint inhibitors (ICIs), has shown promise in improving outcomes for CRC patients. Notably, patients with deficient mismatch repair (dMMR) or microsatellite instability-high (MSI-H) tumors often benefit from ICIs, while the majority of CRC cases, which exhibit proficient mismatch repair (pMMR) or microsatellite-stable (MSS) status, generally show resistance to this approach. It is assumed that the MSI phenotype cause some changes in the tumor microenvironment (TME), thus triggering antitumor immunity and leading to response to immunotherapy. Understanding these differences in the TME relative to MSI status is essential for developing more effective therapeutic strategies. This review provides an overview of the TME components in CRC and explores current approaches aimed at enhancing ICI efficacy in MSS CRC.

New insight in immunotherapy and combine therapy in colorectal cancer

The advent of immune checkpoint inhibitors (ICIs) in colorectal cancer (CRC) treatment marks a major breakthrough. These therapies have proven safer and more effective than traditional radiotherapy and targeted treatments. Immunotherapies like pembrolizumab, nivolumab, and ipilimumab have pioneered new treatment avenues, potentially improving patient outcomes and quality of life. Additionally, advances in immunotherapy have prompted detailed research into CRC therapies, especially those integrating ICIs with conventional treatments, providing new hope for patients and shaping future research and practice. This review delves into the mechanisms of various ICIs and evaluates their therapeutic potential when combined with radiotherapy, chemotherapy, and targeted therapies in clinical settings. It also sheds light on the current application and research involving ICIs in CRC treatment.

A Narrative Review of the Role of Immunotherapy in Metastatic Carcinoma of the Colon Harboring a BRAF Mutation

Patients affected by metastatic carcinoma of the colon/rectum (mCRC) harboring mutations in the BRAF gene (MBRAF) respond poorly to conventional therapy and have a prognosis worse than that of patients without mutations. Despite the promising outcomes of targeted therapy utilizing multi-targeted inhibition of the mitogen-activated protein kinase (MAPK) signaling system, the therapeutic efficacy, especially for the microsatellite stable/DNA proficient mismatch repair (MSS/PMMR) subtype, remains inadequate. Patients with MBRAF/mCRC and high microsatellite instability or DNA deficient mismatch repair (MSI-H/DMMR) exhibit a substantial tumor mutation burden, suggesting a high probability of response to immunotherapy. It is widely acknowledged that MSS/pMMR/mCRC is an immunologically "cold" malignancy that exhibits resistance to immunotherapy. The integration of targeted therapy and immunotherapy may enhance clinical outcomes in patients with MBRAF/mCRC. Efforts to enhance outcomes are exclusively focused on MSS/DMMR-BRAF mutant cancers, which constitute the largest proportion. This review evaluates the clinical efficacy and advancement of novel immune checkpoint blockade therapies for MSI-H/DMMR and MSS/PMMR BRAF mutant mCRC. We examine potential indicators in the tumor immune milieu for forecasting immunotherapeutic response in BRAF mutant mCRC.

Pretreatment MRI Parameters and Neutrophil-to-Lymphocyte Ratio Could Predict the Long-Term Prognosis of Locally Advanced Rectal Cancer Patients With Pathological Complete Response after Neoadjuvant Chemoradiotherapy

BackgroundLocal advanced rectal cancer (LARC) patients who achieved pathological complete response (pCR) after neoadjuvant chemoradiotherapy (NCRT) generally have a favorable prognosis. This retrospective study aimed to evaluate the prognostic value of magnetic resonance imaging (MRI) parameters and neutrophil-to-lymphocyte ratio (NLR) in LARC patients with pCR.MethodsBetween 2015 and 2019, 180 LARC patients who achieved pCR after NCRT and surgery were included. MRI parameters and NLR were evaluated as potential predictors for 5-year overall survival (OS) and disease-free survival (DFS) using the Kaplan-Meier and COX regression analysis.ResultsWith a median follow-up time of 68.3 months, the 5-year OS and DFS rates were 94.2% and 91.4%, respectively. Thirteen patients (7.2%) died, 2 (1.1%) experienced local recurrence, and 15 (8.3%) experienced distant metastases. Pretreatment MRI parameters and NLR were correlated with 5-year OS and DFS in pCR patients in the univariate analysis. The multivariate analysis identified baseline EMVI and NLR as independent predictors for 5-year OS and DFS (all P < .05). Patients in the low-risk group (EMVI-negative and/or NLR ≤ 2.8, n = 159, 88.3%) had a more favorable 5-year DFS compared to those in the high-risk group (EMVI-positive and NLR > 2.8, n = 21, 11.7%) (95.6% vs 59.4%, P < .001), with similar findings for 5-year OS (97.4% vs 70.6%, P < .001).ConclusionsThis study showed that MRI parameters and NLR were associated with long-term prognosis in patients with pCR. These findings could aid in stratifying pCR patients and guide subsequent treatment and follow-up strategies.

Tumor-Infiltrating Immune Cells in Colorectal Cancer

Colorectal cancer encompasses a heterogeneous group of malignancies that differ in pathophysiological mechanisms, immune response and infiltration, therapeutic response, and clinical prognosis. Numerous studies have highlighted the clinical relevance of tumor-infiltrating immune cells among different types of colorectal tumors yet vary in cell type definitions and cell identification strategies. The distinction of immune signatures is particularly challenging when several immune subtypes are involved but crucial to identify novel intercellular mechanisms within the tumor microenvironment. In this review, we compile human and non-human studies on tumor-infiltrating immune cells and provide an overview of immune subtypes, their pathophysiological functions, and their prognostic role in colorectal cancer. We discuss how differentiating immune signatures can guide the development of immunotherapeutic targets and personalized treatment regimens. We analyzed comprehensive human protein biomarker profiles across the entire immune spectrum to improve interpretability and application of tumor studies and to ultimately enhance immunotherapy and advance precision medicine for colorectal cancer patients.

Severe Lymphopenia Predicts Poorer Survival in Patients With Rectal Cancer Undergoing Neoadjuvant Chemoradiation

PURPOSE

Chemoradiation-induced lymphopenia is common and associated with poorer survival in multiple solid malignancies. However, the association between chemoradiation-related lymphopenia and survival outcomes in rectal cancer is yet unclear. The objective of this study was to evaluate the prognostic impact of lymphopenia and its predictors in patients with rectal cancer undergoing neoadjuvant chemoradiation.

METHODS

The inclusion criteria for this single-institution retrospective study were as follows: (1) biopsy-proven diagnosis of rectal adenocarcinoma, (2) receipt of neoadjuvant chemoradiation followed by surgery, and (3) absolute lymphocyte count available prior to and within 12 weeks of chemoradiation. In general, chemoradiation consisted of 5-fluorouracil or capecitabine and radiotherapy with 50.4 Gy over 28 fractions. Lymphopenia was graded according to the Common Terminology Criteria for Adverse Events version 5.0. The primary variable of interest was absolute lymphocyte count nadir within 12 weeks of chemoradiation, dichotomized by <500/μL (grade 3 or worse lymphopenia). The primary endpoint was overall survival. Cox modeling and Kaplan-Meier methods were used to perform survival analyses.

RESULTS

A total of 193 patients were identified with a median follow-up of 68 months. Overall clinical stage was 2 in 21% and 3 in 76%. Median baseline lymphocyte count for the entire cohort was 1700/μL. One hundred ten patients (57%) experienced chemoradiation-related severe lymphopenia. Pathologic complete response rate was 21%; 83% received adjuvant chemotherapy. Lower baseline lymphocyte count was significantly associated with increased risk for chemoradiation-related severe lymphopenia (odds ratio, 1.71). On multivariable Cox regression analysis, chemoradiation-related severe lymphopenia was significantly associated with worse disease-free survival (hazard ratio, 2.64) and overall survival (hazard ratio, 4.32). Five-year overall survival was 79% versus 92%, and 5-year disease-free survival was 70% versus 86% in the cohort that experienced versus did not experience severe lymphopenia, respectively.

DISCUSSION

Chemoradiation-induced lymphopenia is common and a prognostic marker of poorer survival in rectal cancer. Closer observation in high-risk patients and treatment modifications may be potential approaches to mitigating treatment-related lymphopenia. Our findings also suggest an important role of the host immunity in rectal cancer outcomes and support future studies investigating ways to reduce treatment-induced lymphopenia.

Introducing Neoadjuvant Immunotherapy for Colorectal Cancer: Advancing the Frontier

OBJECTIVE

To give surgeons a review of the current and future use of neoadjuvant immunotherapy in patients with localized colorectal cancer (CRC).

BACKGROUND

Immunotherapy has revolutionized the standard of care in oncology and improved survival outcomes in several cancers. However, the applicability of immunotherapy is still an ongoing challenge. Some cancer types are less responsive to immunotherapy, and the heterogeneity in responses within cancer types is poorly understood. Clinical characteristics of the patient, the timing of immunotherapy in relation to surgery, diversities in the immune responses, clonal heterogeneity, different features of the tumor microenvironment, and genetic alterations are some factors among many that may influence the efficacy of immunotherapy.

RESULTS

In this narrative review, we describe the major types of immunotherapy used to treat localized CRC. Furthermore, we discuss the prediction of response to immunotherapy in relation to biomarkers and radiologic assessment. Finally, we consider the future perspectives of clinical implications and response patterns, as well as the potential and challenges of neoadjuvant immunotherapy in localized CRC.

CONCLUSIONS

Establishing mismatch repair (MMR) status at the time of diagnosis is central to the potential use of neoadjuvant immunotherapy, in particular immune checkpoint inhibitors, in localized CRC. To date, efficacy is primarily seen in patients with deficient MMR status and polymerase epsilon mutations, although a small group of patients with proficient MMR does respond. In conclusion, neoadjuvant immunotherapy shows promising complete response rates, which may open a future avenue of an organ-sparing watch-and-wait approach for a group of patients.

Causal impacts of 731 immunocyte phenotypes on colorectal cancer-evidence from a bidirectional two-sample Mendelian randomization

Colorectal cancer is one of the most common and lethal malignancies, and various factors have been confirmed to contribute to its occurrence. However, the causal role of immune cell-specific changes in the development of colorectal cancer has not been investigated. The bidirectional two-sample Mendelian randomization analysis was performed to explore the association between 731 types of immune cell phenotypes-specific changes and colorectal cancer. The inverse variance weighting results indicated that a total of 31 and 28 immune cell phenotypes significantly associated with colorectal cancer in two different datasets, respectively. The primary results of inverse variance weighting Mendelian randomization suggested that the immune cell phenotypes BAFF-R on IgD+ CD38dim (OR = 1.033, 95%CI: 1.005-1.062) and SSC-A on monocyte (OR = 1.055, 95%CI: 1.016-1.096) served as risk factor for colorectal cancer. In addition, the meta-analysis further supports the causal link of BAFF-R on IgD+ CD38dim (pooled OR = 1.035, 95%CI: 1.013-1.059) and SSC-A on monocyte (pooled OR = 1.060, 95%CI: 1.026-1.095) with colorectal cancer. Finally, the inverse variance weighting Mendelian randomization result suggested that genetic determinants of colorectal cancer may decrease the level of HLA DR++ monocyte absolute count (OR = 0.686, 95%CI: 0.508-0.925). Our results indicated that the potential causal association of BAFF-R on IgD+ CD38dim and SSC-A on monocyte with colorectal cancer. The identified immune cells may be appealing drug targets for colorectal cancer, but lack confirmation from real clinical evidence. Further studies are needed to investigate the roles of these immune cells in colorectal cancer.

Innovative Bacterial Therapies and Genetic Engineering Approaches in Colorectal Cancer: A Review of Emerging Strategies and Clinical Implications

Colorectal cancer (CRC) is considered a widespread cancer, ranking second in mortality and incidence among cancer patients worldwide. CRC develops from adenoma to carcinoma through the dynamic interplay of genetic and environmental factors. The conventional modes of treatment, including operation, chemotherapy, and irradiation, are associated with significant challenges, such as drug resistance and toxicity, necessitating the exploration of new treatment modalities. These difficulties reveal the necessity of the emergence of new therapeutic approaches. This review mainly emphasizes the bacterial-based therapies that have recently developed like the engineered bacteriophage therapy and bacterial immunotherapy that pale the existing chemotherapy in terms of toxicity but are effective in killing tumor cells. Also, it also investigates various molecular genetic engineering strategies such as CRISPR-Cas9, CRISPR prime editing and gene silencing to achieve better targeting of CRC. Implementing these new approaches into the forefront of CRC treatment may bring better, more effective therapy with fewer side effects on patients' quality of life.

Tertiary lymphoid structures in colorectal cancer - organization and immune cell interactions

Tertiary lymphoid structures (TLS), formerly recognized as Crohn's-like structures, serve as crucial biomarkers for evaluating the progression of colorectal cancer (CRC). Understanding their spatial distribution, cellular composition, and interactions within CRC is paramount for comprehending the immune response in the tumor microenvironment (TME). TLS are comprised of a T-cellular compartment and a B-cellular compartment, the latter encompassing follicular dendritic cells (FDCs), high endothelial venules (HEVs), and lymphatic vessels. While T helper cells predominate in cancer TLS, the specific functions of their subpopulations remain inadequately understood. Notably, T follicular helper (Tfh) cells play a central role in the activation of CD8+ T cells, and both Tfh cells and Tfh-associated genes have been linked to enhanced CRC survival. In stage II CRC TLS, an escalation in the number of FoxP3+ T regulatory cells (Tregs) is regarded as a negative prognostic factor. Moreover, within TLS, T lymphocytes shield B lymphocytes from the immunosuppressive effects of the TME. B lymphocyte activation is succeeded by class recombination (CSR) and somatic hypermutation (SHM). Dendritic cells (DCs) constitute a vital cellular component of the TLS T compartment. During steady state and early stages of CRC, specialized antigen-presenting cells such as DCs migrate to regional lymph nodes through afferent lymphatics. They deliver MHC antigen-derived peptide complexes (tumor antigens) to naïve CD4+ and CD8+ T cells, which subsequently infiltrate the tumor site as antigen-specific T cells. Key DC markers studied in TLS include CD83 and DC-LAMP. Research has indicated that the DC-LAMP gene signature in tumor TLS reflects Th1 cell targeting, cytotoxicity, and T cell activation. This review comprehensively outlines the functions performed by distinct cell subsets within tertiary lymphoid structures (TLS) in tumors.

Enhancing AI Research for Breast Cancer: A Comprehensive Review of Tumor-Infiltrating Lymphocyte Datasets

The field of immunology is fundamental to our understanding of the intricate dynamics of the tumor microenvironment. In particular, tumor-infiltrating lymphocyte (TIL) assessment emerges as essential aspect in breast cancer cases. To gain comprehensive insights, the quantification of TILs through computer-assisted pathology (CAP) tools has become a prominent approach, employing advanced artificial intelligence models based on deep learning techniques. The successful recognition of TILs requires the models to be trained, a process that demands access to annotated datasets. Unfortunately, this task is hampered not only by the scarcity of such datasets, but also by the time-consuming nature of the annotation phase required to create them. Our review endeavors to examine publicly accessible datasets pertaining to the TIL domain and thereby become a valuable resource for the TIL community. The overall aim of the present review is thus to make it easier to train and validate current and upcoming CAP tools for TIL assessment by inspecting and evaluating existing publicly available online datasets.

Targeting the JAK-STAT pathway in colorectal cancer: mechanisms, clinical implications, and therapeutic potential

Colorectal cancer (CRC) remains one of the most prevalent and fatal malignancies worldwide, consistently ranking among the top three in terms of incidence and mortality. Despite notable advancements in early detection and therapeutic interventions, survival outcomes for advanced-stage CRC are still dismal, largely due to issues such as drug resistance and metastasis. Recent research has increasingly implicated the JAK-STAT signaling pathway as a pivotal contributor to CRC pathogenesis. This evolutionarily conserved pathway plays a key role in transmitting extracellular signals to the nucleus, thereby modulating gene expression involved in numerous fundamental biological processes. In CRC, dysregulation of the JAK-STAT pathway is frequently observed and is strongly associated with tumor progression, including processes such as cellular proliferation, apoptosis, metastasis, immune evasion, and the sustenance of cancer stem cells. Given its integral role in CRC advancement, the JAK-STAT pathway has gained recognition as a viable therapeutic target. Extensive evidence from preclinical and clinical models supports the efficacy and safety of targeting components of the JAK-STAT pathway, presenting new therapeutic possibilities for patients with CRC, particularly in addressing drug resistance and enhancing treatment outcomes. This review offers a detailed exploration of the JAK-STAT pathway, focusing on its regulatory mechanisms in CRC-related malignancies. Moreover, it examines the association between JAK-STAT protein expression, clinical features, prognosis, and its therapeutic potential in CRC management.

Redefining Therapeutic Approaches in Colorectal Cancer: Targeting Molecular Pathways and Overcoming Resistance

Colorectal cancer (CRC) arises through a combination of genetic and epigenetic alterations that affect key pathways involved in tumor growth and progression. This review examines the major molecular pathways driving CRC, including Chromosomal Instability (CIN), Microsatellite Instability (MSI), and the CpG Island Methylator Phenotype (CIMP). Key mutations in genes such as APC, KRAS, NRAS, BRAF, and TP53 activate signaling pathways like Wnt, EGFR, and PI3K/AKT, contributing to tumorigenesis and influencing responses to targeted therapies. Resistance mechanisms, including mutations that bypass drug action, remain challenging in CRC treatment. This review highlights the role of molecular profiling in guiding the use of targeted therapies such as tyrosine kinase inhibitors and immune checkpoint inhibitors. Novel combination treatments are also discussed as strategies to improve outcomes and overcome resistance. Understanding these molecular mechanisms is critical to advancing personalized treatment approaches in CRC and improving patient prognosis.

The single-cell spatial landscape of stage III colorectal cancers

We conducted a spatial analysis using imaging mass cytometry applied to stage III colorectal adenocarcinomas. This study used multiplexed markers to distinguish individual cells and their spatial organization from 52 colorectal cancers. We determined the landscape features of cellular spatial features in the CRC tumor microenvironment. This spatial single-cell analysis identified 10 unique cell phenotypes in the tumor microenvironment that included stromal and immune cells with a subset which had a proliferative phenotype. These special features included spatial neighborhood interactions between single cells as well as different tissue niches, especially the tumor infiltrating lymphocyte regions. We applied a robust statistical analysis to identify significant correlations of cell features with phenotypes such as microsatellite instability or recurrence. We determined that microsatellite stable (MSS) colorectal cancers had an increased risk of recurrence if they had the following features: 1) a low level of stromal tumor-infiltrating lymphocytes, and 2) low interactions between CD4+ T cells and stromal cells. Our results point to the utility of spatial single-cell interaction analysis in defining novel features of the tumor immune microenvironments and providing useful clinical cell-related spatial biomarkers.

Evaluation of prognostic significance of histopathological characteristics and tumor-infiltrating lymphocytes for pancreatic cancer survival

With a 5-year survival of ˂ 10%, pancreatic cancer is one of the leading causes of cancer-related deaths. Given the role of the distribution of tumor-infiltrating lymphocyte (TILs) subtypes in the tumor and its microenvironment in predicting prognosis, the development of new targeted therapies based on T-cell adaptive response has gained considerable attention. This study aimed to examine the peritumoral spread of TILs and its relationship with other prognostic parameters and survival. This study included 60 patients with pancreatic cancer who had undergone surgery with follow-up between 2011 and 2021. Demographic characteristics, tumor histopathological features, peritumoral TILs counts, and intratumoral programmed cell death protein-1 (PD-1) and programmed death ligand - 1 (PD-L1) positivity were evaluated. Furthermore, overall survival and their efficacy in predicting survival according to TNM stage were analyzed. The number of cluster differentiation-3 positive (CD3 P) TILs increased with advancing pathological T stage. CD3 P and CD8 P TIL counts were higher in patients with peripancreatic fatty tissue invasion. Patients with PD-L1 positivity and higher TIL counts had better survival rates. PD-L1-negative patients with a low CD8 positive/total lymph node count (P/T) ratio had a longer survival. Moreover, patients with poorly differentiated tumors with low CD3 P/T and CD8 P/T ratios had a longer survival. The CD3 P/T and CD8 P/T ratios were compatible with the automatic and manual measurements. Age, tumor differentiation, N stage, and peritumoral TIL count and subtype, when evaluated together with the presence of PD-L1 in the tumor tissue, may have prognostic significance for survival in patients with pancreatic cancer.

Isobutyric Acid Promotes Immune Evasion in Colorectal Cancer via Increased PD-L1 Expression

INTRODUCTION

Isobutyric acid (IBA), a short-chain fatty acid, has been unequivocally demonstrated to exert significant influence on the progression of colorectal cancer (CRC). Nevertheless, a comprehensive understanding of its intricate regulatory mechanisms remains elusive.

METHODS

Employing advanced techniques such as western blot, RT-qPCR, and flow cytometry, we systematically investigated the impact of IBA on the expression of PD-L1 in CRC cells. Concurrently, employing RNA silencing technology and small-molecule inhibitors, we delved into the molecular intricacies underlying the regulatory axis of IBA involving ROCK1/c-Myc/PD-L1. Furthermore, through flow cytometry analysis, we examined the alterations in the tumor immune microenvironment following anti-PD-L1 antibody therapy in a murine tumor model treated with IBA.

RESULTS

Elevated levels of IBA were found to robustly activate PD-L1 expression in CRC cells both in vitro and in vivo, concomitantly reshaping the tumor immune microenvironment. Subsequent mechanistic investigations unveiled that IBA, through its interaction and activation of ROCK1, promotes the activation of c-Myc, thereby enhancing the transcription of PD-L1. Silencing of ROCK1 and application of ROCK1 inhibitors effectively reversed the regulatory effects of IBA on PD-L1. Additionally, IBA inhibited the activity of infiltrating CD8+ T cells, resulting in diminished antitumor immunity and attenuating the sensitivity to anti-PD-L1 therapy.

CONCLUSION

Our study elucidates a novel mechanism by which IBA inhibits the sensitivity of CRC to anti-PD-L1 antibody therapy. Emphasizing IBA and its downstream pathways as potential therapeutic targets for immune therapy resistance mechanisms, our findings provide a novel theoretical foundation for overcoming immune therapy resistance.

Spatial Context of Immune Checkpoints as Predictors of Overall Survival in Patients with Resectable Colorectal Cancer Independent of Standard Tumor-Node-Metastasis Stages

SIGNIFICANCE

The identification of specific spatial patterns of immune checkpoint expression that correlate with overall survival in patients with colon cancer suggests a potential prognostic tool for risk stratification and treatment selection. These findings pave the way for the development of novel therapeutic strategies to enhance antitumor immune responses.

Tumour Immunotherapy and Applications of Immunological Products: A Review of Literature

Malignant tumors, characterized by uncontrolled cell proliferation, are a leading global health challenge, responsible for over 9.7 million deaths in 2022, with new cases expected to rise to 35 million annually by 2050. Immunotherapy is preferred to other cancer therapies, offering precise targeting of malignant cells while simultaneously strengthening the immune system's complex responses. Advances in this novel field of science have been closely linked to a deeper knowledge of tumor biology, particularly the intricate interplay between tumor cells, the immune system, and the tumor microenvironment (TME), which are central to cancer progression and immune evasion. This review offers a comprehensive analysis of the molecular mechanisms that govern these interactions, emphasizing their critical role in the development of effective immunotherapeutic products. We critically evaluate the current immunotherapy approaches, including cancer vaccines, adoptive T cell therapies, and cytokine-based treatments, highlighting their efficacy and safety. We also explore the latest advancements in combination therapies, which synergistically integrate multiple immunotherapeutic strategies to overcome resistance and enhance therapeutic outcomes. This review offers key insights into the future of cancer immunotherapy with a focus on advancing more effective and personalized treatment strategies.

Predictors of response to immunotherapy in colorectal cancer

Colorectal cancer (CRC) is a major cause of cancer-related deaths globally. While treatment advancements have improved survival rates, primarily through targeted therapies based on KRAS, NRAS, and BRAF mutations, personalized treatment strategies for CRC remain limited. Immunotherapy, mainly immune checkpoint blockade, has shown efficacy in various cancers but is effective in only a small subset of patients with CRC with deficient mismatch repair (dMMR) proteins or high microsatellite instability (MSI). Recent research has challenged the notion that CRC is immunologically inert, revealing subsets with high immunogenicity and diverse lymphocytic infiltration. Identifying precise biomarkers beyond dMMR and MSI is crucial to expanding immunotherapy benefits. Hence, exploration has extended to various biomarker sources, such as the tumor microenvironment, genomic markers, and gut microbiota. Recent studies have introduced a novel classification system, consensus molecular subtypes, that aids in identifying patients with CRC with an immunogenic profile. These findings underscore the necessity of moving beyond single biomarkers and toward a comprehensive understanding of the immunological landscape in CRC, facilitating the development of more effective, personalized therapies.

Advancements in tumor-infiltrating lymphocytes: Historical insights, contemporary milestones, and future directions in oncology therapy

Tumor-infiltrating lymphocytes (TILs) are a subtype of immune cells that infiltrate and accumulate within tumors. Studies proved that TILs can be used as prognostic and predictive markers for cancer patients' responses to immunotherapy. This review explores the modern knowledge of TILs, the challenges and opportunities for utilizing TILs in cancer treatment, such as the rise of therapies under TIL circumstances, the identification of biomarkers for TIL activity, and methods used to isolate and expand TILs for therapeutic use. Ongoing clinical trials and promising results in different cancer types are highlighted, including melanoma, ovarian, and colorectal cancer. This also focuses on ongoing efforts to improve TIL-based therapies by identifying the specific subsets of TILs that are most effective in treating cancer and developing methods to increase the functionality and persistence of TILs in the tumor microenvironment. The article recapitulates the present state TILs therapy, ongoing research, and improvements to its potency.

Novel drug delivery systems in colorectal cancer: Advances and future prospects

Colorectal cancer (CRC) is an abnormal proliferation of cells within the colon and rectum, leading to the formation of polyps and disruption of mucosal functions. The disease development is influenced by a combination of factors, including inflammation, exposure to environmental mutagens, genetic alterations, and impairment in signaling pathways. Traditional treatments such as surgery, radiation, and chemotherapy are often used but have limitations, including poor solubility and permeability, treatment resistance, side effects, and post-surgery issues. Novel Drug Delivery Systems (NDDS) have emerged as a superior alternative, offering enhanced drug solubility, precision in targeting cancer cells, and regulated drug release. Thereby addressing the shortcomings of conventional therapies and showing promise for more effective CRC management. The present review sheds light on the pathogenesis, signaling pathways, biomarkers, conventional treatments, need for NDDS, and application of NDDS against CRC. Additionally, clinical trials, ongoing clinical trials, marketed formulations, and patents on CRC are also covered in the present review.

Single-cell RNA sequencing reveals intratumoral heterogeneity and multicellular community in primary hepatocellular carcinoma underlying microvascular invasion

Background

Microvascular invasion (MVI) is associated with an unfavorable prognosis and early recurrence of hepatocellular carcinoma (HCC), which is the crucial pathological hallmark of immunotherapy. While microvascular invasion (MVI) in hepatocellular carcinoma (HCC) currently lacks a detailed single-cell analysis of the tumor microenvironment (TME), it holds significant promise for immunotherapy using immune checkpoint inhibitors (ICI).

Methods

We performed single-cell RNA sequencing (scRNA-seq) on 3 MVI positive (MVIP) and 14 MVI-negative (MVIN) tumor tissues, as well as their paired adjacent non-tumoral tissues.

Results

We identified SPP1+ macrophages and CD4+ proliferative T cells as intertumoral populations critical for the formation of cold tumors and immunosuppressive environments in MVI-positive patients and verified their prognostic value in correlation with MVIP HCC patients. Additionally, we identified SPP1+ dominated interactions between SPP1+ macrophages and the immunosuppressive T population as contributors to MVI destruction and tumorigenesis.

Conclusions

We provide a comprehensive single-cell atlas of HCC patients with MVI, shedding light on the immunosuppressive ecosystem and upregulated signaling associated with MVI. These findings demonstrate that intercellular mechanisms drive MVI and provide a potential immunotherapeutic target for HCC patients with HCC and underlying MVI.

From Crypts to Cancer: A Holistic Perspective on Colorectal Carcinogenesis and Therapeutic Strategies

Colorectal cancer (CRC) represents a significant global health burden, with high incidence and mortality rates worldwide. Recent progress in research highlights the distinct clinical and molecular characteristics of colon versus rectal cancers, underscoring tumor location's importance in treatment approaches. This article provides a comprehensive review of our current understanding of CRC epidemiology, risk factors, molecular pathogenesis, and management strategies. We also present the intricate cellular architecture of colonic crypts and their roles in intestinal homeostasis. Colorectal carcinogenesis multistep processes are also described, covering the conventional adenoma-carcinoma sequence, alternative serrated pathways, and the influential Vogelstein model, which proposes sequential APC, KRAS, and TP53 alterations as drivers. The consensus molecular CRC subtypes (CMS1-CMS4) are examined, shedding light on disease heterogeneity and personalized therapy implications.

Exploring the immunometabolic potential of Danggui Buxue Decoction for the treatment of IBD-related colorectal cancer

Danggui Buxue (DGBX) decoction is a classical prescription composed of Astragali Radix (AR) and Angelicae Sinensis Radix (ASR), used to enrich blood, and nourish Qi in Chinese medicine, with the potential to recover energy and stimulate metabolism. Chronic inflammation is a risk factor in the development of inflammatory bowel disease (IBD)-related colorectal cancer (CRC). More importantly, AR and ASR have anti-inflammatory and anti-cancer activities, as well as prefiguring a potential effect on inflammation-cancer transformation. We, therefore, aimed to review the immunometabolism potential of DGBX decoction and its components in this malignant transformation, to provide a helpful complement to manage the risk of IBD-CRC. The present study investigates the multifaceted roles of DGBX decoction and its entire components AR and ASR, including anti-inflammation effects, anti-cancer properties, immune regulation, and metabolic regulation. This assessment is informed by a synthesis of scholarly literature, with more than two hundred articles retrieved from PubMed, Web of Science, and Scopus databases within the past two decades. The search strategy employed utilized keywords such as "Danggui Buxue", "Astragali Radix", "Angelicae Sinensis Radix", "Inflammation", and "Metabolism", alongside the related synonyms, with a particular emphasis on high-quality research and studies yielding significant findings. The potential of DGBX decoction in modulating immunometabolism holds promise for the treatment of IBD-related CRC. It is particularly relevant given the heterogeneity of CRC and the growing trend towards personalized medicine, but the precise and detailed mechanism necessitate further in vivo validation and extensive clinical studies to substantiate the immunometabolic modulation and delineate the pathways involved.

Immunotherapy for colorectal cancer

Colorectal cancer is the third most common cancer and the second most lethal cancer in the world. The main cause of the disease is due to dietary and behavioral factors. The treatment of this complex disease is mainly based on traditional treatments, including surgery, radiotherapy, and chemotherapy. Due to its high prevalence and high morbidity, more effective treatments with fewer side effects are urgently needed. In recent years, immunotherapy has become a potential therapeutic alternative and one of the fastest-developing treatments. Immunotherapy inhibits tumor growth by activating or enhancing the immune system to recognize and attack cancer cells. This review presents the latest immunotherapies for immune checkpoint inhibitors, cell therapy, tumor-infiltrating lymphocytes, and oncolytic viruses. Some of these have shown promising results in clinical trials and are used in clinical treatment.

Identification and validation of Rab GTPases RAB13 as biomarkers for peritoneal metastasis and immune cell infiltration in colorectal cancer patients

Background

As one of the most common cancer, colorectal cancer (CRC) is with high morbidity and mortality. Peritoneal metastasis (PM) is a fatal state of CRC, and few patients may benefit from traditional therapies. There is a complex interaction between PM and immune cell infiltration. Therefore, we aimed to determine biomarkers associated with colorectal cancer peritoneal metastasis (CRCPM) and their relationship with immune cell infiltration.

Methods

By informatic analysis, differently expressed genes (DEGs) were selected and hub genes were screened out. RAB13, one of the hub genes, was identificated from public databases and validated in CRC tissues. The ESTIMATE, CEBERSORT and TIMER algorithms were applied to analyze the correlation between RAB13 and immune infiltration in CRC. RAB13's expression in different cells were analyzed at the single-cell level in scRNA-Seq. The Gene Set Enrichment Analysis (GSEA) was performed for RAB13 enrichment and further confirmed. Using oncoPredict algorithm, RAB13's impact on drug sensitivity was evaluated.

Results

High RAB13 expression was identified in public databases and led to a poor prognosis. RAB13 was found to be positively correlated with the macrophages and other immune cells infiltration and from scRNA-Seq, RAB13 was found to be located in CRC cells and macrophages. GSEA revealed that high RAB13 expression enriched in a various of biological signaling, and oncoPredict algorithm showed that RAB13 expression was correlated with paclitaxel sensitivity.

Conclusion

Our study indicated clinical role of RAB13 in CRC-PM, suggesting its potential as a therapeutic target in the future.

Inflammation and Colorectal Cancer: A Meta-Analysis of the Prognostic Significance of the Systemic Immune-Inflammation Index (SII) and the Systemic Inflammation Response Index (SIRI)

The overall prognosis for colorectal cancer (CRC) remains challenging as the survival time varies widely, even in patients with the same stage of disease. Recent studies suggest prognostic relevance of the novel markers of systemic inflammation, the systemic immune-inflammation index (SII), and the systemic inflammation response index (SIRI). We conducted a comprehensive meta-analysis to assess the prognostic significance of the SII and the SIRI in CRC. We searched the relevant literature for observational studies, and random effects models were employed to conduct a statistical analysis using the metaanalysisonline.com platform. Pooled effect sizes were reported with hazard ratios (HRs) and corresponding 95% confidence intervals (CI). Data from 29 studies published between 2016 and 2024, comprising 10,091 participants, were included in our meta-analysis on SII. CRC patients with high SII levels had worse disease outcomes, which were associated with poor OS (HR: 1.75; 95% CI: 1.4-2.19) and poor PFS/DFS/RFS (HR: 1.25; 95% CI: 1.18-1.33). This increased risk of worse OS was present irrespective of the treatment strategy, sample size (<220 and ≥220), and cutoff used to define high and low SII (<550 and ≥550) groups. Based on data from five studies comprising 2362 participants, we found a strong association between the high SIRI and worse OS (HR: 2.65; 95% CI: 1.6-4.38) and DFS/RFS (HR: 2.04; 95% CI: 1.42-2.93). According to our results, both the SII and SIRI hold great promise as prognostic markers in CRC. Further validations are needed for their age- and stage-specific utility in the clinical routine.

Prognostic value of neutrophil-to-lymphocyte ratio at diagnosis in colorectal cancer: propensity score analysis

INTRODUCTION

baseline neutrophil-to-lymphocyte ratio (NLR) at the time of colorectal cancer (CRC) diagnosis has been proposed as a predictor of long-term survival. The aim of this study was to analyze its usefulness in a homogeneous population with control of the main confounding factors.

METHODOLOGY

observational study of 836 patients who underwent surgery for CRC. Patients were divided into two groups: NLR ≤ 3.3 vs NLR > 3.3. To control for confounders, they were matched one-to-one by propensity analysis. A final cohort of 526 patients was included in the study.

RESULTS

the two groups were mismatched in terms of age, comorbidity, tumor stage, rectal location, and neoadjuvant therapy. Once matching was performed, baseline NLR was statistically significantly associated with long-term survival (p < 0.001) and behaved as an independent prognostic factor for survival (p = 0.001; HR: 1.99; 95 % CI: 1.32-3.00) when adjusted in a Cox regression model using age (p < 0.001; HR: 1.04; 95 % CI: 1.02-1.06) and the Charlson Comorbidity Index (p < 0.001; HR: 1.40; 95 % CI: 1.27-1.55). Neoadjuvant therapy lost its statistical significance (p = 0.137; HR: 1.59; 95 % CI: 0.86-2.93).

CONCLUSIONS

a high baseline NLR (> 3.3) in patients with colorectal cancer at diagnosis represents a poor prognostic factor in terms of survival. Its use in routine practice could intensify therapeutic strategies and follow-up in these patients.

Preoperative prediction of lymph node metastasis in colorectal cancer using 18F-FDG PET/CT peritumoral radiomics analysis

BACKGROUND

Radiomics has been used in the diagnosis of tumor lymph node metastasis (LNM). However, to date, most studies have been based on intratumoral radiomics. Few studies have focused on the use of 18F-fluorodeoxyglucose positron emission computed tomography (18F-FDG PET/CT) peritumoral radiomics for the diagnosis of LNM in colorectal cancer (CRC).

PURPOSE

Determining the value of radiomics features extracted from 18F-FDG PET/CT images of the peritumoral region in predicting LNM in patients with CRC.

METHODS

The clinical data and preoperative 18F-FDG PET/CT images of 244 CRC patients were retrospectively analyzed. Intratumoral and peritumoral radiomics features were screened using the mutual information method, and least absolute shrinkage and selection operator regression. Based on the selected radiomics features, a radiomics score (Rad-score) was calculated, and independent risk factors obtained from univariate and multivariate logistic regression analyses were used to construct clinical and combined (Radiomics + Clinical) models. The performance of these models was evaluated using the DeLong test, while their clinical utility was assessed by decision curve analysis. Finally, a nomogram was constructed to visualize the predictive model.

RESULTS

The most optimal set of features retained by the feature filtering process were all peritumoral radiomic features. Carcinoembryonic antigen levels, PET/CT-reported lymph node status and Rad-score were found to be independent risk factors for LNM. All three LNM risk assessment models exhibited good predictive performance, with the combined model showing the best classification results, with areas under the curve of 0.85 and 0.76 in the training and validation groups, respectively. The DeLong test revealed that the performance of the combined model was superior to that of the clinical and radiomics models in both the training and validation groups, although this difference was only statistically significant in the training group. DCA indicated that the combined model displayed better clinical utility.

CONCLUSIONS

18F-FDG PET/CT peritumoral radiomics is uniquely suited to predict the presence of LNM in patients with CRC. In particular, the predictive efficacy of LNM for precision therapy and individualized patient management can be improved by using a combination of clinical risk factors.

Colorectal medullary carcinoma: a pathological subtype with intense immune response and potential to benefit from immune checkpoint inhibitors

INTRODUCTION

Different pathological types of colorectal cancer have distinguished immune landscape, and the efficacy of immunotherapy will be completely different. Colorectal medullary carcinoma, accounting for 2.2-3.2%, is characterized by massive lymphocyte infiltration. However, the attention to the immune characteristics of colorectal medullary carcinoma is insufficient.

AREA COVERED

We searched the literature about colorectal medullary carcinoma on PubMed through November 2023to investigate the hallmarks of colorectal medullary carcinoma's immune landscape, compare medullary carcinoma originating from different organs and provide theoretical evidence for precise treatment, including applying immunotherapy and BRAF inhibitors.

EXPERT OPINION

Colorectal medullary carcinoma is a pathological subtype with intense immune response, with six immune characteristics and has the potential to benefit from immunotherapy. Mismatch repair deficiency, ARID1A missing and BRAF V600E mutation often occurs. IFN-γ pathway is activated and PD-L1 expression is increased. Abundant lymphocyte infiltration performs tumor killing function. In addition, BRAF mutation plays an important role in the occurrence and development, and we can consider the combination of BRAF inhibitors and immunotherapy in patients with BRAF mutant. The exploration of colorectal medullary carcinoma will arouse researchers' attention to the correlation between pathological subtypes and immune response, and promote the process of precise immunotherapy.

Reduced Abundance of Phocaeicola in Mucosa-associated Microbiota Is Associated with Distal Colorectal Cancer Metastases Possibly through an Altered Local Immune Environment

Objectives

The aim of this study was to identify the microbiota whose decrease in tumor area was associated with the metastatic process of distal colorectal cancer (CRC).

Methods

Twenty-eight consecutive patients with distal CRC undergoing surgical resection in our hospital were enrolled. Microbiota in 28 specimens from surgically resected colorectal cancers were analyzed using 16S ribosomal ribonucleic acid gene amplicon sequencing and the relative abundance (RA) of microbiota was evaluated. The densities of tumor-infiltrating lymphocytes (TIL) and tumor associated macrophages (TAM) in the colorectal cancers were immunohistochemically evaluated.

Results

Phocaeicola was the most abundant microbiota in normal mucosa. The RA of Phocaeicola in tumor tissues tended to be lower than that in normal mucosa although the difference was not significant (p=0.0732). The RA of Phocaeicola at tumor sites did not correlate either with depth of tumor invasion (pT-stage) or tumor size, however they were significantly reduced in patients with nodal metastases (p<0.05) and those with distant metastases (p<0.001). The RA of Phocaeicola at tumor sites showed positive correlation with the densities of CD3(+) or CD8(+) TIL. Since P. vulgatus was the most dominant species (47%) of the Phocaeicola, the RA of P. vulgatus and CRC metastasis and its association with TIL and TAM were also investigated. P. vulgatus showed a similar trend to genus Phocaeicola but was not statistically significant.

Conclusions

A relative reduction of Phocaeicola attenuates the local anti-tumor immune response in distal CRC, which may facilitate metastatic spread.