Biomarkers in Immunotherapy-Based Precision Treatments of Digestive System Tumors

Immune checkpoint inhibitors in colorectal cancer: limitation and challenges

Colorectal cancer exhibits a notable prevalence and propensity for metastasis, but the current therapeutic interventions for metastatic colorectal cancer have yielded suboptimal results. ICIs can decrease tumor development by preventing the tumor's immune evasion, presenting cancer patients with a new treatment alternative. The increased use of immune checkpoint inhibitors (ICIs) in CRC has brought several issues. In particular, ICIs have demonstrated significant clinical effectiveness in patients with MSI-H CRC, whereas their efficacy is limited in MSS. Acquired resistance can still occur in patients with a positive response to ICIs. This paper describes the efficacy of ICIs currently in the clinical treatment of CRC, discusses the mechanisms by which acquired resistance occurs, primarily related to loss and impaired presentation of tumor antigens, reduced response of IFN-λ and cytokine or metabolic dysregulation, and summarizes the incidence of adverse effects. We posit that the future of ICIs hinges upon the advancement of precise prediction biomarkers and the implementation of combination therapies. This study aims to elucidate the constraints associated with ICIs in CRC and foster targeted problem-solving approaches, thereby enhancing the potential benefits for more patients.

Correlation of CT parameters and PD-L1 expression status in gastric cancer

OBJECTIVE

We aimed to explore the correlation between routine computed tomography (CT) imaging features and programmed cell death ligand-1(PD-L1) expression status in gastric cancer and evaluate the predictive value of imaging parameters for this immunotherapy biomarker.

MATERIALS AND METHODS

Patients with gastric adenocarcinoma who underwent abdominal CT three-stage enhanced scan and PD-L1 immunohistochemical testing before treatment were retrospectively examined. All diagnoses were confirmed through pathology. According to the expression status of PD-L1, they were divided into the positive (CPS ≥ 5) or negative group (CPS < 5). Baseline CT imaging features were collected. Diagnostic performances of the different variables were evaluated using receiver operating characteristic (ROC) curve.

RESULTS

In total, 67 patients (17 women and 50 men; mean age: 59.55 ± 10.22 years) with gastric adenocarcinoma were included in the study. The overall stages, probability of maximum lymph node short diameter > 1 cm and peak of lesion enhancement occurring in the arterial phase were statistically significant between the two groups (p < 0.05). Moreover, the arterial enhancement fraction (AEF) was significantly higher in the positive group than that in the negative group (p < 0.05), and ROC curve analysis showed that the AEF exhibited a high evaluation efficacy (area under the curve [AUC] = 0.724 [95% confidence interval (CI): 0.602-0.826]). The combined parameters had the best diagnostic efficacy (AUC = 0.825 [95%CI: 0.716-0.933]), sensitivity (75.00%), and specificity (81.40%).

CONCLUSIONS

These findings confirm a correlation between CT imaging features and PD-L1 expression status in gastric cancer, and AEF may help evaluate high PD-L1 expression and select patients suitable for immunotherapy.

Clinical significance of peripheral T-cell receptor repertoire profiling and individualized nomograms in patients with gastrointestinal cancer treated with anti-programmed death 1 antibody

Background

Immune checkpoint inhibitors (ICIs) have significant clinical benefit for a subset of patients with gastrointestinal cancers (GICs) including esophageal cancer, gastric cancer and colorectal cancer. However, it is difficult to predict which patients will respond favorably to immune checkpoint blockade therapy. Thus, this study was initiated to determine if peripheral T-cell receptor (TCR) repertoire profiling could predict the clinical efficacy of anti-programmed death 1 (PD-1) treatment.

Methods

Blood samples from 31 patients with GICs were collected before anti-PD-1 antibody treatment initiation. The clinical significance of the combinatorial diversity evenness of the TCR repertoire [the diversity evenness 50 (DE50), with high values corresponding to less clonality and higher TCR diversity] from peripheral blood mononuclear cells (PBMCs) was evaluated in all the enrolled patients. A highly predictive nomogram was set up based on peripheral TCR repertoire profiling. The performance of the nomogram was assessed by receiver operating characteristic (ROC) curve, concordance index (C-index), and calibration curves, and decision curve analysis (DCA) was used to assess its clinical applicability.

Results

Compared to non-responders [progression disease (PD)], the DE50 scores were significantly higher in responders [stable disease (SD) and partial response (PR)] (P=0.018). Patients with a high DE50 score showed better progression-free survival (PFS) than those with a low DE50 score (P=0.0022). The multivariable Cox regression demonstrated that high DE50 and low platelet-lymphocyte ratio (PLR) were significant independent predictors for better PFS when treated with anti-PD-1 antibody. Furthermore, a highly predictive nomogram was set up based on peripheral TCR repertoire profiling. The area under the curves (AUCs) of this system at 3-, 6- and 12-month PFS reached 0.825, 0.802, and 0.954, respectively. The nomogram had a C-index of 0.768 [95% confidence interval (CI): 0.658-0.879]. Meanwhile, the calibration curves also demonstrated the reliability and stability of the model.

Conclusions

High DE50 scores were predictive of a favorable response and longer PFS to anti-PD-1 treatment in GIC patients. The nomogram based on TCR repertoire profiling was a reliable and practical tool, which could provide risk assessment and clinical decision-making for individualized treatment of patients.

Development of Tumor Markers for Breast Cancer Immunotherapy

Although breast cancer treatment has been developed remarkably in recent years, it remains the primary cause of death among women. Immune checkpoint blockade therapy has significantly altered the way breast cancer is treated, although not all patients benefit from the changes. At present, the most effective mechanism of immune checkpoint blockade application in malignant tumors is not clear and efficacy may be influenced by many factors, including host, tumor, and tumor microenvironment dynamics. Therefore, there is a pressing need for tumor immunomarkers that can be used to screen patients and help determine which of them would benefit from breast cancer immunotherapy. At present, no single tumor marker can predict treatment efficacy with sufficient accuracy. Multiple markers may be combined to more accurately pinpoint patients who will respond favorably to immune checkpoint blockade medication. In this review, we have examined the breast cancer treatments, developments in research on the role of tumor markers in maximizing the clinical efficacy of immune checkpoint inhibitors, prospects for the identification of novel therapeutic targets, and the creation of individualized treatment plans. We also discuss how tumor markers can provide guidance for clinical practice.

Mechanisms and biomarkers of immune-related adverse events in gastric cancer

Immune-checkpoint inhibitors (ICIs), different from traditional cancer treatment models, have shown unprecedented anti-tumor effects in the past decade, greatly improving the prognosis of many malignant tumors in clinical practice. At present, the most widely used ICIs in clinical immunotherapy for a variety of solid tumors are monoclonal antibodies against cytotoxic T lymphocyte antigen-4 (CTLA-4), programmed cell death protein 1 (PD-1) and their ligand PD-L1. However, tumor patients may induce immune-related adverse events (irAEs) while performing immunotherapy, and irAE is an obstacle to the prospect of ICI treatment. IrAE is a non-specific disease caused by immune system imbalance, which can occur in many tissues and organs. For example, skin, gastrointestinal tract, endocrine system and lung. Although the exact mechanism is not completely clear, related studies have shown that irAE may develop through many ways. Such as excessive activation of autoreactive T cells, excessive release of inflammatory cytokines, elevated levels of autoantibodies, and common antigens between tumors and normal tissues. Considering that the occurrence of severe IrAE not only causes irreversible damage to the patient's body, but also terminates immunotherapy due to immune intolerance. Therefore, accurate identification and screening of sensitive markers of irAE are the main beneficiaries of ICI treatment. Additionally, irAEs usually require specific management, the most common of which are steroids and immunomodulatory therapies. This review aims to summarize the current biomarkers for predicting irAE in gastric cancer and their possible mechanisms.

The Influence of the Microbiome on Immunotherapy for Gastroesophageal Cancer

Immunotherapy has shown promise as a treatment option for gastroesophageal cancer, but its effectiveness is limited in many patients due to the immunosuppressive tumor microenvironment (TME) commonly found in gastrointestinal tumors. This paper explores the impact of the microbiome on the TME and immunotherapy outcomes in gastroesophageal cancer. The microbiome, comprising microorganisms within the gastrointestinal tract, as well as within malignant tissue, plays a crucial role in modulating immune responses and tumor development. Dysbiosis and reduced microbial diversity are associated with poor response rates and treatment resistance, while specific microbial profiles correlate with improved outcomes. Understanding the complex interactions between the microbiome, tumor biology, and immunotherapy is crucial for developing targeted interventions. Microbiome-based biomarkers may enable personalized treatment approaches and prediction of patient response. Interventions targeting the microbiome, such as microbiota-based therapeutics and dietary modifications, offer the potential for reshaping the gut microbiota and creating a favorable TME that enhances immunotherapy efficacy. Further research is needed to reveal the underlying mechanisms, and large-scale clinical trials will be required to validate the efficacy of microbiome-targeted interventions.

Monocyte subsets associated with the efficacy of anti‑PD‑1 antibody monotherapy

Immune checkpoint inhibitors (ICIs) are among the most notable advances in cancer immunotherapy; however, reliable biomarkers for the efficacy of ICIs are yet to be reported. Programmed death (PD)-ligand 1 (L1)-expressing CD14+ monocytes are associated with shorter overall survival (OS) time in patients with cancer treated with anti-PD-1 antibodies. The present study focused on the classification of monocytes into three subsets: Classical, intermediate and non-classical. A total of 44 patients with different types of cancer treated with anti-PD-1 monotherapy (pembrolizumab or nivolumab) were enrolled in the present study. The percentage of each monocyte subset was investigated, and the percentage of cells expressing PD-L1 or PD-1 within each of the three subsets was further analyzed. Higher pretreatment classical monocyte percentages were correlated with shorter OS (r=-0.32; P=0.032), whereas higher non-classical monocyte percentages were correlated with a favorable OS (r=0.39; P=0.0083). PD-L1-expressing classical monocytes accounted for a higher percentage of the total monocytes than non-classical monocytes with PD-L1 expression. In patients with non-small cell lung cancer (NSCLC), a higher percentage of PD-L1-expressing classical monocytes was correlated with shorter OS (r=-0.60; P=0.012), which is similar to the observation for the whole patient cohort. Comparatively, higher percentages of non-classical monocytes expressing PD-L1 were significantly associated with better OS, especially in patients with NSCLC (r=0.60; P=0.010). Moreover, a higher percentage of non-classical monocytes contributed to prolonged progression-free survival in patients with NSCLC (r=0.50; P=0.042), with similar results for PD-L1-expressing non-classical monocytes. The results suggested that the percentage of monocyte subsets in patients with cancer before anti-PD-1 monotherapy may predict the treatment efficacy and prognosis. Furthermore, more classical monocytes and fewer non-classical monocytes, especially those expressing PD-L1, are involved in shortening OS time, which may indicate the poor efficiency of anti-PD-1 treatment approaches.

Concordance in detection of microsatellite instability by PCR and NGS in routinely processed tumor specimens of several cancer types

BACKGROUND

Microsatellite instability (MSI) occurs in several cancer types and is commonly used for prognosis and as a predictive biomarker for immune checkpoint therapy.

METHODS

We analyzed n = 263 formalin-fixed paraffin-embedded (FFPE) tumor specimens (127 colorectal cancer (CRC), 55 endometrial cancer (EC), 33 stomach adenocarcinoma (STAD), and 48 solid tumor specimens of other tumor types) with a capillary electrophoresis based multiplex monomorphic marker MSI-PCR panel and an amplicon-based NGS assay for microsatellite instability (MSI+). In total, n = 103 (39.2%) cases with a known defect of the DNA mismatch repair system (dMMR), determined by a loss in protein expression of MSH2/MSH6 (n = 48, 46.6%) or MLH1/PMS2 (n = 55, 53.4%), were selected. Cases with an isolated loss of MSH6 or PMS2 were excluded.

RESULTS

The overall sensitivity and specificity of the NGS assay in comparison with the MSI-PCR were 92.2% and 98.8%. With CRC cases a nearly optimal concordance was reached (sensitivity 98.1% and specificity 100.0%). Whereas EC cases only show a sensitivity of 88.6% and a specificity of 95.2%, caused by several cases with instability in less than five monomorphic markers, which could be difficult to analyze by NGS (subtle MSI+ phenotype).

CONCLUSIONS

MSI analysis of FFPE DNA by NGS is feasible and the results show a high concordance in comparison with the monomorphic marker MSI-PCR. However, cases with a subtle MSI+ phenotype, most frequently manifest in EC, have a risk of a false-negative result by NGS and should be preferentially analyzed by capillary electrophoresis.

The predictive role of soluble programmed death ligand 1 in digestive system cancers

Introduction

The prognostic role of soluble programmed death ligand 1 (sPD-L1) in digestive system cancers (DSCs) remains inconclusive. This study aimed to explore the predictive value of sPD-L1 expression in DSCs.

Methods

Comprehensive searches were run on the electronic databases (PubMed, Web of Science, EMBASE, and the Cochrane Library) to identify studies that assessed the prognostic role of sPD-L1 in DSCs. Review Manager software (version 5.3) was used for all analyses. Pooled data for survival outcomes were measured as hazard ratios (HRs), 95% confidence intervals (CIs), and odds ratios and their 95% CIs.

Results

The search identified 18 studies involving 2,070 patients with DSCs. The meta-outcome revealed that a high level of sPD-L1 was related to poorer overall survival (HR, 3.06; 95% CI: 2.22-4.22, p<0.001) and disease-free survival (HR, 2.53; 95% CI: 1.67-3.83, p<0.001) in DSCs. Individually, the prognostic significance of high level of sPD-L1 expression was the highest in hepatic cell carcinoma (HR, 4.76; p<0.001) followed by gastric cancer (HR=3.55, p<0.001).

Conclusion

sPD-L1 may be a prognostic factor in DSCs for overall survival and disease-free survival. Inflammatory cytokines, treatment approaches, and other factors may affect the expression of sPD-L1. Therefore, the prognostic value of sPD-L1 for recurrence and metastasis should be further investigated. sPD-L1 may also predict response to treatment. Well-designed prospective studies with standard assessment methods should be conducted to determine the prognostic value of sPD-L1 in DSCs.

Relationship between SUVmax on 18F-FDG PET and PD-L1 expression in liver metastasis lesions after colon radical operation

PURPOSE

Our study was to investigate the correlation correlation between FDG uptake and PD-L1 expression of liver metastasis in patients with colon cancer, and to determine the value of FDG-PET in predicting PD-L1 expression in liver metastasis of colon cancer.

METHODS

A total of 72 patients with confirmed liver metastasis of colon cancer were included in this retrospective study. The PD-L1 expression and immune cell infiltrating of tumors were determined through immunohistochemistry staining. The SUVmax of liver metastasis lesions were assessed using ¹⁸ F-FDG PET/CT. The correlation between PD-L1 expression and the clinicopathological were evaluated by the Cox proportional hazards model and the Kaplan-Meier survival analysis.

RESULTS

PD-L1 expression was significantly correlated with FDG uptake (SUVmax), tumor size, differentiation, survival and cytotoxic T cells infiltration in liver metastasis of colon cancer (P < 0.05). And liver metastases with high counts of infiltrating cytotoxic T cells showed greater FDG uptake than those with low counts of infiltrating cytotoxic T cells. The SUVmax of liver metastases and the degree of differentiation of metastases were closely related to PD-L1 expression, and were independent risk factors.The combined assessment of SUVmax values and tthe degree of differentiation of metastase can help determine PD-L1 expression in liver metastasis of colon cancer.

CONCLUSIONS

FDG uptake in liver metastasis of colon cancer was positively correlated with the PD-L1 expression and the number of cytotoxic T cells infiltration. The joint evaluation of two parameters, SUVmax and degree of differentiation, can predict PD-L1 expression in liver metastases.

Non-invasive plasma testing for CD274 UTR structural variations by next-generation sequencing in cancer

Immunotherapy is now the main choice of systemic therapy for many cancer patients, while current biomarkers for tumor immunotherapy may be limited by the accessibility of patient tumor tissue or tumor neoplastic content. Rare mutation in the 5' and 3'-untranslated region (UTR) of CD274 gene (Protein name: PD-L1) has been recently reported in hematologic and solid tumors as a potential biomarker for assessing efficacy during immunotherapy. However, multi-omics analysis for CD274 UTR region, especially circulating tumor DNA (ctDNA), have been little explored in the pan-cancer perspective. We developed a cSMART2.0 technology featured with higher capture efficiency and homogeneity to detect this rare structural variant in 2249 Chinese patients' cohort with multiple cancers. An incidence of 0.36% was detected in this cohort, consistent with TCGA (The Cancer Genome Atlas), while the prevalence of SV in CD274 UTR region in liver and breast cancer were significantly higher than TCGA. The liquid biopsy result from ctDNA was 100% concordance with gDNA result getting from tumor tissue detection, and further validated by immunohistochemistry (IHC) and multiplex immunofluorescence (mIF) experiments. Patients carrying this SV in CD274 UTR region without driver gene mutation responded to immune checkpoint inhibitors (ICIs). This study proves that rare structural variants in CD274 UTR region exist in various cancer in Chinese population for the first time, which can induce immune escape and be used for prediction of response to ICIs. Liquid biopsy based cSMART 2.0 technology could offer more sensitive and accurate detection to navigate potential ICIs patients and to benefit patients with advanced disease when tissue samples are not available.

Mutations Status of NOTCH Signaling Pathway Predict Prognosis of Immune Checkpoint Inhibitors in Colorectal Cancer

Purpose

In recent years, tumour immunotherapy has ushered in a new era of oncology treatment. However, the use of immune checkpoint inhibitors (ICIs) in the treatment of CRC remains limited. There is an urgent clinical need for precise biomarkers that can aid in the screening and treatment of CRC subtypes. Therefore, we focused on the NOTCH pathway mutation status and conducted a systematic analysis for its predictive value of ICI therapy efficacy.

Methods

We collected mutational and clinical data from cohorts of CRC patients treated with ICIs. The relationship between NOTCH pathway mutations (NOTCH-MT) and CRC immunotherapy prognosis was analysed using univariate and multivariate Cox regression models. CRC cohort data from The Cancer Genome Atlas (TCGA) database were combined to obtain a comprehensive overview of immunogenicity and tumour microenvironment (TME) differences among different NOTCH pathway mutation statuses.

Results

We observed greater infiltration of M1 macrophages, CD8+ T cells, neutrophils, and activated natural killer (NK) cells with NOTCH-MT status. Immunogenicity was also significantly higher in patients with NOTCH-MT, as were tumour mutational burden (TMB), neoantigen load (NAL), and the number of mutations in DNA damage repair (DDR) pathways.

Conclusion

NOTCH-MT status was strongly associated with the prognosis of CRC patients treated with ICIs and is expected to serve as a novel biomarker and therapeutic target for CRC.

A G-quadruplex stabilizer, CX-5461 combined with two immune checkpoint inhibitors enhances in vivo therapeutic efficacy by increasing PD-L1 expression in colorectal cancer

PURPOSE

Immune checkpoint inhibitors (ICIs) alone or in combination with chemotherapy can improve the limited efficacy of colorectal cancer (CRC) immunotherapy. CX-5461 causes substantial DNA damage and genomic instability and can increase ICIs' therapeutic efficacies through tumor microenvironment alteration.

RESULTS

We analyzed whether CX-5461 enhances ICIs' effects in CRC and discovered that CX-5461 causes severe DNA damage, including cytosolic dsDNA appearance, in various human and mouse CRC cells. Our bioinformatics analysis predicted CX-5461-based interferon (IFN) signaling pathway activation in these cells, which was verified by the finding that CX-5461 induces IFN-α and IFN-β secretion in these cells. Next, cGAMP, phospho-IRF3, CCL5, and CXCL10 levels exhibited significant posttreatment increases in CRC cells, indicating that CX-5461 activates the cGAS-STING-IFN pathway. CX-5461 also enhanced PD-L1 expression through STAT1 activation. CX-5461 alone inhibited tumor growth and prolonged survival in mice. CX-5461+anti-PD-1 or anti-PD-L1 alone exhibited synergistic growth-suppressive effects against CRC and breast cancer. CX-5461 alone or CX-5461+anti-PD-1 increased cytotoxic T-cell numbers and reduced myeloid-derived suppressor cell numbers in mouse spleens.

CONCLUSIONS

Therefore, clinically, CX-5461 combined with ICIs for CRC therapy warrants consideration because CX-5461 can turn cold tumors into hot ones.

Predictive biomarkers of colon cancer immunotherapy: Present and future

Immunotherapy has revolutionized colon cancer treatment. Immune checkpoint inhibitors (ICIs) have shown clinical benefits for colon cancer patients, especially those with high microsatellite instability (MSI-H). In 2020, the US Food and Drug Administration (FDA)-approved ICI pembrolizumab as the first-line treatment for metastatic MSI-H colon cancer patients. Additionally, neoadjuvant immunotherapy has presented efficacy in treating early-stage colon cancer patients. Although MSI has been thought of as an effective predictive biomarker for colon cancer immunotherapy, only a small proportion of colon cancer patients were MSI-H, and certain colon cancer patients with MSI-H presented intrinsic or acquired resistance to immunotherapy. Thus, further search for predictive biomarkers to stratify patients is meaningful in colon cancer immunotherapy. Except for MSI, other biomarkers, such as PD-L1 expression level, tumor mutation burden (TMB), tumor-infiltrating lymphocytes (TILs), certain gut microbiota, ctDNA, and circulating immune cells were also proposed to be correlated with patient survival and ICI efficacy in some colon cancer clinical studies. Moreover, developing new diagnostic techniques helps identify accurate predictive biomarkers for colon cancer immunotherapy. In this review, we outline the reported predictive biomarkers in colon cancer immunotherapy and further discuss the prospects of technological changes for biomarker development in colon cancer immunotherapy.

CDK2AP1 influences immune infiltrates and serves as a prognostic indicator for hepatocellular carcinoma

Background: Hepatocellular carcinoma (HCC) is a tumor with high malignancy and poor 5-years survival rate. Excellent tumor markers are very important for early clinical diagnosis and prognosis evaluation. Previous studies have shown that CDK2AP1 (Cyclin-dependent kinase 2-associated protein 1) is involved in cell-cycle and epigenetic regulation. In the present study, we assess CDK2AP1 expression, prognostic value, immunomodulatory and possible influencing pathways in HCC.

Method: The Cancer Genome Atlas (TCGA) database was used to analyse gene expression, clinicopathology and prognosis. The protein level of CDK2AP1 in HCC tissues was detected in the Human Protein Atlas (HPA) database. The immune score in HCC to CDKAP1 expression were analyzed using ESTIMATE. Furthermore, we use Tumor IMmune Estimation Resource (TIMER) database to study CDK2AP1 expression and Immune Infiltration Levels in HCC. Co-expressed genes of CDK2AP1 were predicted and elaborated by LinkedOmics.

Results: In normal liver tissues, the expression of CDK2AP1 was significantly lower than tumor tissues, and was correlated with the level of clinical stage and histologic grade in HCC patients. Patients with high expression of CDK2AP1 have a poor prognosis than patients with low CDK2AP1 expression. CDK2AP1 expression level exhibits significantly positive correlations with the number of infiltrating B cells, CD4+ T cells, CD8+ T cells, Macrophages, Neutrophils, and DCs in HCC tissues. KEGG enrichment analysis showed that the related pathways affected by CDK2AP1 mainly include: Fc gamma R-mediated phagocytosis, Th1 and Th2 cell differentiation, Cell cycle, etc. Both in vitro and in vivo experiments confirmed that CDK2AP1 promotes the proliferation and metastasis in hepatocellular carcinoma. Our results highlight the role of CDK2AP1 as an important prognostic indicator and immunotherapy target for HCC patients.

Conclusion: We found CDK2AP1 as a new prognostic biomarker for HCC, which could help explain changes in the biological processes and immune environment lead to liver cancer development. Therefore, CDK2AP1 is a potential new target for HCC therapy.

Microsatellite Instability: From the Implementation of the Detection to a Prognostic and Predictive Role in Cancers

Microsatellite instability (MSI) has been identified in several tumors arising from either germline or somatic aberration. The presence of MSI in cancer predicts the sensitivity to immune checkpoint inhibitors (ICIs), particularly PD1/PD-L1 inhibitors. To date, the predictive role of MSI is currently used in the selection of colorectal cancer patients for immunotherapy; moreover, the expansion of clinical trials into other cancer types may elucidate the predictive value of MSI for non-colorectal tumors. In clinical practice, several assays are used for MSI testing, including immunohistochemistry (IHC), polymerase chain reaction (PCR) and next-generation sequencing (NGS). In this review, we provide an overview of MSI in various cancer types, highlighting its potential predictive/prognostic role and the clinical trials performed. Finally, we focus on the comparison data between the different assays used to detect MSI in clinical practice.

Serine Protease Inhibitor Kazal Type 1, A Potential Biomarker for the Early Detection, Targeting, and Prediction of Response to Immune Checkpoint Blockade Therapies in Hepatocellular Carcinoma

Background

We aimed to characterize serine protease inhibitor Kazal type 1 (SPINK1) as a gene signature for the early diagnosis, molecular targeting, and prediction of immune checkpoint blockade (ICB) treatment response of hepatocellular carcinoma (HCC).

Methods

The transcriptomics, proteomics, and phenotypic analyses were performed separately or in combination.

Results

We obtained the following findings on SPINK1. Firstly, in the transcriptomic training dataset, which included 279 stage I and II tumor samples (out of 1,884 stage I–IV HCC specimens) and 259 normal samples, significantly higher area under curve (AUC) values and increased integrated discrimination improvement (IDI) and net reclassification improvement (NRI) were demonstrated for HCC discrimination in SPINK1-associated models compared with those of alpha-fetoprotein (AFP). The calibration of both SPINK1-related curves fitted significantly better than that of AFP. In the two independent transcriptomic validation datasets, which included 201, 103 stage I-II tumor and 192, 169 paired non-tumor specimens, respectively, the obtained results were consistent with the above-described findings. In the proteomic training dataset, which included 98 stage I and II tumor and 165 normal tissue samples, the analyses also revealed better AUCs and increased IDI and NRI in the aforementioned SPINK1-associated settings. A moderate calibration was shown for both SPINK1-associated models relative to the poor results of AFP. Secondly, in the in vitro and/or in vivo murine models, the wet-lab experiments demonstrated that SPINK1 promoted the proliferation, clonal formation, migration, chemoresistance, anti-apoptosis, tumorigenesis, and metastasis of HCC cells, while the anti-SPINK1 antibody inhibited the growth of the cells, suggesting that SPINK1 has “tumor marker” and “targetable” characteristics in the management of HCC. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that SPINK1 was engaged in immunity-related pathways, including T-cell activation. Thirdly, in the transcriptomic analyses of the 368 HCC specimens from The Cancer Genome Atlas (TCGA) cohort, the high abundance of SPINK1 was positively correlated with the high levels of activated tumor-infiltrating CD4⁺ and CD8⁺ T lymphocytes and dendritic and natural killer cells, while there were also positive correlations between SPINK1 and immune checkpoints, including PD-1, LAG-3, TIM-3, TIGIT, HAVCR2, and CTLA-4. The ESTIMATE algorithm calculated positive correlations between SPINK1 and the immune and ESTIMATE scores, suggesting a close correlation between SPINK1 and the immunogenic microenvironment within HCC tissues, which may possibly help in predicting the response of patients to ICB therapy.

Conclusions

SPINK1 could be a potential biomarker for the early detection, targeted therapy, and prediction of ICB treatment response in the management of HCC.

Identification of APC Mutation as a Potential Predictor for Immunotherapy in Colorectal Cancer

To date, anticancer immunotherapy has presented some clinical benefits to most of advanced mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) colorectal cancer (CRC) patients. In addition to MSI status, we aimed to reveal the potential predictive value of adenomatous polyposis coli (APC) gene mutations in CRC patients. A total of 238 Chinese CRC patients was retrospectively identified and analyzed for clinical features and gene alternations in APC-mutant type (MT) and APC-wild-type (WT) groups. Clinical responses were then evaluated from the public TCGA database and MSKCC immunotherapy database. Although programmed cell death ligand 1 (PD-L1) level, MSI status, loss of heterogeneity at the human leukocyte antigen (HLA LOH), and tumor neoantigen burden (TNB) level were not statistically different between the APC-MT group and APC-WT group, tumor mutation burden (TMB) level was significantly higher in APC-MT patients (P < 0.05). Furthermore, comutation analysis for APC mutations revealed co-occurring genomic alterations of PCDHB7 and exclusive mutations of CTNNB1, BRAF, AFF3, and SNX25 (P < 0.05). Besides, overall survival from MSKCC-CRC cohort was longer in the APC-WT group than in the APC-MT group (HR 2.26 (95% CI 1.05–4.88), P < 0.05). Furthermore, most of patients in the APC-WT group were detected as high-grade immune subtypes (C2–C4) comparing with those in the APC-MT group. In addition, the percentages of NK T cells, Treg cells, and fibroblasts cells were higher in APC-WT patients than in APC-MT patients (P < 0.05). In summary, APC mutations might be associated with poor outcomes for immunotherapy in CRC patients regardless of MSI status. This study suggested APC gene mutations might be a potential predictor for immunotherapy in CRC.

Elevated Carcinoembryonic Antigen at the Time of Recurrence as a Poor Prognostic Factor in Colorectal Cancer: A Propensity Score Matching Analysis

There are few studies on the prognostic impact of CEA level at the time of recurrence in recurrent colorectal cancer. The objective of this study was to evaluate the prognostic value of serum CEA levels at the time of recurrence in patients with recurrent colorectal cancer. Between 2007 and 2014, 962 consecutive recurrent patients for colorectal cancer were analyzed. These patients were divided into two groups according to CEA level at the time of recurrence (r-CEA): high r-CEA (≥5 ng/ml) (n = 428) and normal r-CEA (<5 ng/ml) (n = 534). The prognostic effects of r-CEA were evaluated by one-to-one propensity score matching (PSM) to adjust factors between groups. After matching, a total of 778 patients, 389 per group, were analyzed. After matching, the 5-year disease-free survival rate for the high r-CEA group was significantly lower than that for the normal r-CEA group. The 5-year overall survival rate was 56.5% in the high r-CEA group and 66.0% in the normal r-CEA group (p = 0.008). The 5-year cancer-specific survival rate was 61.7% in the high group and 67.5% in the normal group (p = 0.035). In a multivariate analysis of prognostic factors, high preoperative CEA level at the time of recurrence, poor histologic grade, and lymphatic invasion were associated with poorer overall survival. The high r-CEA level group showed significantly poorer prognosis than the normal r-CEA group. Therefore, the r-CEA level can be used as a prognostic factor in recurrent colorectal cancer. Aggressive adjuvant treatment needs to be considered for patients with an initially high CEA level and lymph node positivity who are prone to recurrence.

Biomarkers of Response and Resistance to Immunotherapy in Microsatellite Stable Colorectal Cancer: Toward a New Personalized Medicine

Immune Checkpoint Inhibitors (ICIs) are well recognized as a major immune treatment modality for multiple types of solid cancers. However, for colorectal cancer (CRC), ICIs are only approved for the treatment of Mismatch-Repair-Deficient and Microsatellite Instability-High (dMMR/MSI-H) tumors. For the vast majority of CRC, that are not dMMR/MSI-H, ICIs alone provide limited to no clinical benefit. This discrepancy of response between CRC and other solid cancers suggests that CRC may be inherently resistant to ICIs alone. In translational research, efforts are underway to thoroughly characterize the immune microenvironment of CRC to better understand the mechanisms behind this resistance and to find new biomarkers of response. In the clinic, trials are being set up to study biomarkers along with treatments targeting newly discovered immune checkpoint molecules or treatments combining ICIs with other existing therapies to improve response in MSS CRC. In this review, we will focus on the characteristics of response and resistance to ICIs in CRC, and discuss promising biomarkers studied in recent clinical trials combining ICIs with other therapies.

A Review of Emerging Biomarkers for Immune Checkpoint Inhibitors in Tumors of the Gastrointestinal Tract

In recent years, immune checkpoint inhibition (ICI) therapy has made a tremendous improvement in the treatment of malignant tumors of gastrointestinal tract, especially for those with metastatic or recurrent lesions. However, while some patients benefit from ICI, others do not. In fact, predictive biomarkers can play a crucial role in screening patients who may benefit from a selected or targeted treatment, including immunotherapies such as programmed death-1/programmed death-1 ligand 1 (PD-1/PD-L1) inhibitors. A variety of techniques can be used to detect and quantify tumor biomarkers, each of which has a specific clinical application scenario and limitations. Cancer biomarkers in the gastrointestinal system involve an extremely complex network that requires careful interpretation and analysis. Different prognostic or predictive biomarkers are playing important roles in various tumor types, stages, and pathology/molecular subgroups, sometimes overlapping. Expression levels of biomarkers vary between different tumor types and even between the different lesions in the same tumor, depending on the heterogeneity of the patient, the tumor types, and the techniques of detection. The present systematic review comprehensively summarizes the potential biomarkers of immunotherapy, such as PD-1/PD-L1, total mutation burden (TMB), and tumor-infiltrating lymphocytes (TILs) in various gastrointestinal tumors, including tumors of the colon, stomach, esophagus, liver, and pancreas, to assist future application of immunotherapy and patient selection in clinical practice.

Predictive molecular markers for the treatment with immune checkpoint inhibitors in colorectal cancer

Colorectal cancer is one of the most common malignant tumors and, hence, has become one of the most important public health issues in the world. Treatment with immune checkpoint inhibitors (ICIs) successfully improves the survival rate of patients with melanoma, non-small-cell lung cancer, and other malignancies, and its application in metastatic colorectal cancer is being actively explored. However, a few patients develop drug resistance. Predictive molecular markers are important tools to precisely screen patient groups that can benefit from treatment with ICIs. The current article focused on certain important predictive molecular markers for ICI treatment in colorectal cancer, including not only some of the mature molecular markers, such as deficient mismatch repair (d-MMR), microsatellite instability-high (MSI-H), tumor mutational burden (TMB), programmed death-ligand-1 (PD-L1), tumor immune microenvironment (TiME), and tumor-infiltrating lymphocytes (TILs), but also some of the novel molecular markers, such as DNA polymerase epsilon (POLE), polymerase delta 1 (POLD1), circulating tumor DNA (ctDNA), and consensus molecular subtypes (CMS). We have reviewed these markers in-depth and presented the results from certain important studies, which suggest their applicability in CRC and indicate their advantages and disadvantages. We hope this article is helpful for clinicians and researchers to systematically understand these markers and can guide the treatment of colorectal cancer.

Conversion therapy with tislelizumab for high microsatellite instability, unresectable stage III gastric cancer: a case report

Gastric cancer (GC) is the fifth-highest ranked cancer for incidence and second for mortality from cancer worldwide. Conversion therapy has recently emerged as an alternative therapy for advanced/metastatic GC patients who are unable to undergo surgical resection at the time of diagnosis. Herein, we present the case of a patient with unresectable stage III GC of high microsatellite instability (MSI), high tumor mutation burden (TMB), and Epstein-Barr virus (EBV) positive. The patient received conversion therapy involving a combination of chemotherapy and immunotherapy regimens. After 3 courses of chemotherapy combined with tislelizumab, the patient underwent laparoscopic radical total gastrectomy. The pathological examination demonstrated that there was no cancerous tissue at the proximal or distal end of the tumor and no lymph node metastases in the lesser or greater curvature, indicating a pathologic complete response. Thereafter, the patient continued tislelizumab treatment to prevent postoperative carcinoma recurrence and metastasis, and to improve prognosis. In conclusion, our study confirmed that chemotherapy combined with immunotherapy is a promising conversion therapy for GC patients with locally unresectable lesions or distant lymph node metastasis, and these findings warrant large-scale clinical studies. This report highlights the clinical importance of next-generation sequencing technology in investigating therapeutic strategy to provide the maximal clinical benefit for patients with GC.

Clinical Study of Sintilimab as Second-Line or Above Therapy in Patients With Advanced or Metastatic Gastric Cancer: A Retrospective Study

Background

The present study was conducted to analyze the clinical efficacy and safety of sintilimab as second-line or above therapy for patients with advanced or metastatic gastric cancer.

Methods

Patients with advanced or metastatic gastric cancer that progressed after prior systemic therapies and treated with sintilimab from March 2019 to July 2020 were retrospectively analyzed in this study. The primary end point was progression-free survival (PFS). Secondary end points included objective response rate (ORR), disease control rate (DCR), overall survival (OS), and safety.

Results

Fifty-two patients with advanced or metastatic gastric cancer received sintilimab monotherapy or combination therapy after they failed from prior systemic therapies. Eight patients achieved partial response (PR), 26 patients had stable disease (SD), and 18 patients had progressive disease (PD). The ORR and DCR were 15.4% (8/52) and 65.4% (34/52), respectively. Median PFS was 2.5 months (95% CI = 2.0–3.0), and median OS was 5.8 months (95% CI = 4.9–6.7). The ORR and DCR were 30.0% (6/20) and 80.0% (16/20), respectively, in intestinal subtype, which were superior than in non-intestinal subtype (ORR: 6.3%, DCR: 56.3%). Patients with intestinal subtype obtained longer PFS (4.0 vs. 1.9) and OS (9.0 vs. 4.1) than those with non-intestinal subtype. The incidence of grade 3–4 adverse events was 44.2%.

Conclusions

Sintilimab monotherapy or combination therapy provides a feasible therapeutic strategy for patients with advanced or metastatic gastric cancer who failed from prior systemic therapies. The efficacy of sintilimab in intestinal subtype was superior than that in non-intestinal subtype.

CTLA-4 Synergizes With PD1/PD-L1 in the Inhibitory Tumor Microenvironment of Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is highly invasive and carries high mortality due to limited therapeutic strategies. In other solid tumors, immune checkpoint inhibitors (ICIs) target cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and programmed death 1 (PD1), and the PD1 ligand PD-L1 has revolutionized treatment and improved outcomes. However, the relationship and clinical significance of CTLA-4 and PD-L1 expression in ICC remains to be addressed. Deciphering CTLA-4 and PD-L1 interactions in ICC enable targeted therapy for this disease. In this study, immunohistochemistry (IHC) was used to detect and quantify CTLA-4, forkhead box protein P3 (FOXP3), and PD-L1 in samples from 290 patients with ICC. The prognostic capabilities of CTLA-4, FOXP3, and PD-L1 expression in ICC were investigated with the Kaplan-Meier method. Independent risk factors related to ICC survival and recurrence were assessed by the Cox proportional hazards models. Here, we identified that CTLA-4⁺ lymphocyte density was elevated in ICC tumors compared with peritumoral hepatic tissues (P <.001), and patients with a high density of CTLA-4⁺ tumor-infiltrating lymphocytes (TILs^{CTLA-4 High}) showed a reduced overall survival (OS) rate and increased cumulative recurrence rate compared with patients with TILs^{CTLA-4 Low} (P <.001 and P = .024, respectively). Similarly, patients with high FOXP3⁺ TILs (TILs^{FOXP3 High}) had poorer prognoses than patients with low FOXP3⁺ TILs (P = .021, P = .034, respectively), and the density of CTLA-4⁺ TILs was positively correlated with FOXP3⁺ TILs (Pearson r = .31, P <.001). Furthermore, patients with high PD-L1 expression in tumors (Tumor^{PD-L1 High}) and/or TILs^{CTLA-4 High} presented worse OS and a higher recurrence rate than patients with TILs^{CTLA-4 Low}Tumor^{PD-L1 Low}. Moreover, multiple tumors, lymph node metastasis, and high Tumor^PD-L1/TILs^CTLA-4 were independent risk factors of cumulative recurrence and OS for patients after ICC tumor resection. Furthermore, among ICC patients, those with hepatolithiasis had a higher expression of CTLA-4 and worse OS compared with patients with HBV infection or undefined risk factors (P = .018). In conclusion, CTLA-4 is increased in TILs in ICC and has an expression profile distinct from PD1/PD-L1. Tumor^PD-L1/TILs^CTLA-4 is a predictive factor of OS and ICC recurrence, suggesting that combined therapy targeting PD1/PD-L1 and CTLA-4 may be useful in treating patients with ICC.