Indoleamine 2,3-dioxygenase 1 and Programmed Cell Death-ligand 1 Co-expression Predicts Poor Pathologic Response and Recurrence in Esophageal Squamous Cell Carcinoma after Neoadjuvant Chemoradiotherapy

A randomized, open-label, phase 3 trial of pembrolizumab plus epacadostat versus sunitinib or pazopanib as first-line treatment for metastatic renal cell carcinoma (KEYNOTE-679/ECHO-302)

BACKGROUND

Immunotherapy-based combinations have emerged as standard therapies for patients with metastatic renal cell carcinoma (mRCC). Pembrolizumab, a PD-1 inhibitor, combined with epacadostat, an indoleamine 2,3-deoxygenase 1 selective inhibitor, demonstrated promising antitumor activity in a phase 1 study in advanced solid tumors, including mRCC.

METHODS

KEYNOTE-679/ECHO-302 was a randomized, open-label, parallel-group, multicenter, phase 3 study (NCT03260894) that compared pembrolizumab plus epacadostat with sunitinib or pazopanib as first-line treatment for mRCC. Eligible patients had histologically confirmed locally advanced or metastatic clear cell RCC and had not received systemic therapy. Patients were randomly assigned 1:1 to pembrolizumab 200 mg IV every 3 weeks plus epacadostat 100 mg orally twice daily versus sunitinib 50 mg orally once daily (4 weeks on treatment followed by 2 weeks off treatment) or pazopanib 800 mg orally once daily. Original dual primary end points were progression-free survival and overall survival. Enrollment was stopped when a phase 3 study in melanoma of pembrolizumab plus epacadostat compared with pembrolizumab monotherapy did not meet its primary end point. This protocol was amended, and primary end point was changed to investigator-assessed objective response rate (ORR) per RECIST 1.1.

RESULTS

One-hundred-twenty-nine patients were randomly assigned to receive pembrolizumab plus epacadostat (n = 64) or sunitinib/pazopanib (n = 65). Median (range) follow-up, defined as time from randomization to data cutoff, was 10.3 months (2.2-14.3) and 10.3 months (2.7-13.8) in the pembrolizumab plus epacadostat and sunitinib/pazopanib arms, respectively. ORRs were similar between pembrolizumab plus epacadostat (31.3% [95% CI 20.2-44.1] and sunitinib/pazopanib (29.2% [18.6-41.8]). Grade 3-5 treatment-related adverse events occurred in 34.4% and 42.9% of patients in the pembrolizumab plus epacadostat and sunitinib/pazopanib arms, respectively. One patient in the sunitinib/pazopanib arm died of septic shock (not treatment-related). Circulating kynurenine levels decreased in the pembrolizumab plus epacadostat arm, but not to levels observed in healthy subjects.

CONCLUSIONS

ORRs were similar between pembrolizumab plus epacadostat and sunitinib/pazopanib as first-line treatment in patients with mRCC. Safety and tolerability appeared similar between treatment arms; no new safety concerns were identified. Antitumor responses observed in patients with RCC receiving pembrolizumab plus epacadostat may be driven primarily by pembrolizumab.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; NCT03260894 .

Therapeutic implications of signaling pathways and tumor microenvironment interactions in esophageal cancer

Esophageal cancer (EC) is significantly influenced by the tumor microenvironment (TME) and altered signaling pathways. Downregulating these pathways in EC is essential for suppressing tumor development, preventing metastasis, and enhancing therapeutic outcomes. This approach can increase tumor sensitivity to treatments, enhance patient outcomes, and inhibit cancer cell proliferation and spread. The TME, comprising cellular and non-cellular elements surrounding the tumor, significantly influences EC's development, course, and treatment responsiveness. Understanding the complex relationships within the TME is crucial for developing successful EC treatments. Immunotherapy is a vital TME treatment for EC. However, the heterogeneity within the TME limits the application of anticancer drugs outside clinical settings. Therefore, identifying reliable microenvironmental biomarkers that can detect therapeutic responses before initiating therapy is crucial. Combining approaches focusing on EC signaling pathways with TME can enhance treatment outcomes. This integrated strategy aims to interfere with essential signaling pathways promoting cancer spread while disrupting factors encouraging tumor development. Unraveling aberrant signaling pathways and TME components can lead to more focused and efficient treatment approaches, identifying specific cellular targets for treatments. Targeting the TME and signaling pathways may reduce metastasis risk by interfering with mechanisms facilitating cancer cell invasion and dissemination. In conclusion, this integrative strategy has significant potential for improving patient outcomes and advancing EC research and therapy. This review discusses the altered signaling pathways and TME in EC, focusing on potential future therapeutics.

Relationship Between CD8+ T Cells and Prognosis of Esophageal Cancer Patients: A Systematic Review and Meta-analysis

Tumor infiltrating lymphocytes (TILs), especially CD8+ T cells, play an important role in the process of anti-tumor immune response and are significantly correlated with the prognosis of esophageal cancer (EC), but there are also inconsistent conclusions. This study aimed to comprehensively evaluate the relationship between invasive CD8+ T cells and the prognosis in patients with EC through meta-analysis, and to provide a basis for prognosis and immunotherapy for EC. Articles related to CD8+ T cells and EC prognosis in PubMed, Cochrane Library, Embase, and CNKI were searched. Cancer specific survival (CSS), overall survival (OS) and disease-free survival (DFS) served as endpoint events. Besides, Stata15.0 was adopted for meta-analysis, and hazard ratio (HR) and 95% confidence interval (95%CI) for calculation of combined effect sizes. Total 547 articles were retrieved and 27 articles were finally enrolled, including 3988 cases of EC patients. Meta-analysis showed that high CD8 expression levels in tumor tissues, especially those in cancer nests, were associated with longer OS (HR = 0.74, 95% CI 0.67-0.81) and DFS (HR = 0.90, 95% CI 0.85-0.95) in EC patients (P < 0.05). CD8+ T cells play an important role in the prognosis of EC patients and are indispensable components for the immune score of EC.

Indoleamine-2,3 dioxygenase: a fate-changer of the tumor microenvironment

Indoleamine-2,3 dioxygenase is a rate-limiting enzyme in the tryptophan catabolism in kynurenine pathways that has an immunosuppressive effect and supports cancer cells to evade the immune system in different cancer types. Diverse cytokines and pathways upregulate the production of indoleamine-2,3 dioxygenase enzymes in the tumor microenvironment and cause more production and activity of this enzyme. Ultimately, this situation results in anti-tumor immune suppression which is in favor of tumor growth. Several inhibitors such as 1-methyl-tryptophan have been introduced for indoleamine-2,3 dioxygenase enzyme and some of them are widely utilized in pre-clinical and clinical trials. Importantly at the molecular level, indoleamine-2,3 dioxygenase is positioned in a series of intricate signaling and molecular networks. Here, the main objective is to provide a focused view of indoleamine-2,3 dioxygenase enhancer pathways and propose further studies to cover the gap in available information on the function of indoleamine-2,3 dioxygenase enzyme in the tumor microenvironment.

Association of Sialic Acid-Binding Immunoglobulin-Like Lectin 15 With Phenotypes in Esophageal Squamous Cell Carcinoma in the Setting of Neoadjuvant Chemoradiotherapy

IMPORTANCE

Sialic acid-binding immunoglobulin-like lectin 15 (Siglec-15) is a novel immune checkpoint molecule that is highly homologous to programmed cell death ligand 1 (PD-L1), but information remains limited about its role in esophageal squamous cell carcinoma (ESCC).

OBJECTIVE

To explore the expression pattern and association of Siglec-15 with outcomes among patients with ESCC who received neoadjuvant chemoradiotherapy (CRT).

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study was conducted at an academic institution in China. Participants included patients with ESCC who underwent neoadjuvant CRT and esophagectomy between June 2002 and December 2018. Multiplexed immunofluorescence staining was used to evaluate the expression of Siglec-15 and PD-L1 in tumor cells (TCs) or tumor-associated macrophages based on pre-CRT biopsies. Different immune phenotypes have been proposed and further validated in an independent cohort. Data analysis was conducted from January to May 2021.

EXPOSURES

Siglec-15 or PD-L1 positivity vs negativity.

MAIN OUTCOMES AND MEASURES

Pathologic complete response (pCR), overall survival (OS), and recurrence-free survival (RFS).

RESULTS

Of 130 participants (median [range] age, 56 [42-73] years; 108 [83.1%] male participants) in the primary cohort, 58 patients (44.6%) achieved a pCR after neoadjuvant CRT. Siglec-15 and PD-L1 were detected in both TCs and macrophages. The percentage of Siglec-15-positive macrophages was notably higher than that of Siglec-15-positive TCs (median [IQR]: 34.4% [12.7%-64.3%] vs 4.8% [0.7%-25.6%]; P < .001). TC-Siglec-15 expression was significantly and positively associated with macrophage-Siglec-15 expression (r = 0.78; P < .001). Siglec-15 positivity was significantly associated with a higher rate of pCR (37 of 70 [52.9%] vs 21 of 60 [35.0%]; P = .04), more favorable OS (hazard ratio [HR], 0.46; 95% CI, 0.25-0.85; P = .01), and RFS (HR, 0.48; 95% CI, 0.26-0.88; P = .02). However, PD-L1 positivity in TCs was negatively associated with survival. Stratification analysis further revealed that patients with combined Siglec-15 positivity and PD-L1 negativity had better survival than those with other phenotypes. Major findings were reproducible in a validation cohort with 55 patients.

CONCLUSIONS AND RELEVANCE

In this cohort study of patients with ESCC receiving neoadjuvant CRT, Siglec-15 positivity was associated with a better pathological response and more favorable survival. Siglec-15 could serve as a novel biomarker to identify potential candidates that may benefit from immunotherapy combined with CRT.

A tumor immune microenvironment-related integrated signature can predict the pathological response and prognosis of esophageal squamous cell carcinoma following neoadjuvant chemoradiotherapy: A multicenter study in China

BACKGROUND

Currently, there are insufficient indicators for the reliable assessment of treatment response following neoadjuvant chemoradiotherapy (nCRT) in patients with esophageal squamous cell carcinoma (ESCC). Considering the essential role of protein-coding and non-coding RNAs in gene regulation and cellular processes, we systematically explored the molecular features and clinical significance of mRNA and lncRNA in 249 pretreatment biopsies from four hospitals in three districts with a high incidence of ESCC patients in China.

METHODS

During the discovery phrase, 13 differentially expressed genes were identified and validated between samples with a complete pathological response (pCR) and those with an incomplete pathological response (<pCR). Subsequently, we constructed a predictive mRNA and lncRNA signature (SERPINE1, LINC00592, and PRKAG2-AS1) using Fisher's linear discriminant analysis (FLDA) with stepwise variant-selection, followed by validation of its predictive ability in both internal and external cohorts.

RESULTS

Our signature showed great value in predicting the response to nCRT among ESCC samples and acted as an independent predictive indicator, in addition to demonstrating great potential in estimating patient prognosis. Interestingly, we found that patients with a high signature score had lower PD-L1 and IDO1 expression levels but higher CD8⁺ T cells infiltration, suggesting that PD-L1 and IDO1 are negatively correlated with a high signature score and further associated with pCR and a better prognosis.

CONCLUSION

The present study identified a promising three-gene-based predictive signature that has powerful clinical implications for the identification of pCR and a good prognosis among patients with ESCC. Further immune-related exploration may provide an opportunity for future therapeutic combination.

Lacticaseibacillus rhamnosus R0011 secretome attenuates Salmonella enterica serovar Typhimurium secretome-induced intestinal epithelial cell monolayer damage and pro-inflammatory mediator production in intestinal epithelial cell and antigen-presenting cell co-cultures

Certain lactic acid bacteria (LAB) are associated with immune modulatory activities including down-regulation of pro-inflammatory gene transcription and expression. While host antigen-presenting cells (APCs) and intestinal epithelial cells (IEC) can interact directly with both pathogenic and commensal bacteria through innate immune pattern recognition receptors, recent evidence indicates indirect communication through secreted molecules is an important inter-domain communication mechanism. This communication route may be especially important in the context of IEC and APC interactions which shape host immune responses within the gut environment. We have previously shown that the Lacticaseibacillus rhamnosus R0011 secretome (LrS) dampens pro-inflammatory gene transcription and mediator production from Tumor Necrosis Factor-α and Salmonella enterica serovar Typhimurium secretome (STS)-challenged HT-29 IECs through the induction of negative regulators of innate immunity. However, many questions remain about interactions mediated through these bacterial-derived soluble components and the resulting host immune outcomes in the context of IEC and APC interactions. In the present study, we examined the ability of the LrS to down-regulate pro-inflammatory gene transcription and cytokine production from STS-challenged T84 human IEC and THP-1 human monocyte co-cultures. Cytokine and chemokine profiling revealed that apically delivered LrS induces apical secretion of macrophage inhibitory factor (MIF) and down-regulates STS-induced pro-inflammatory mediator secretion into the apical and basolateral chambers of the T84/THP-1 co-culture. Transcriptional profiling confirmed these results, as the LrS attenuated STS challenge-induced CXCL8 and NFκB1 expression in T84 IECs and THP-1 APCs. Interestingly, the LrS also reversed STS-induced damage to monolayer transepithelial resistance (TER) and permeability, results which were confirmed by ZO-1 gene expression and immunofluorescence visualization of ZO-1 expression in T84 IEC monolayers. The addition of a MIF-neutralizing antibody abrogated the ability of the LrS to reverse STS-induced damage to T84 IEC monolayer integrity, suggesting a novel role for MIF in maintaining IEC barrier function and integrity in response to soluble components derived from LAB. The results presented here provide mechanistic evidence for indirect communication mechanisms used by LAB to modulate immune responses to pathogen challenge, using in vitro approaches which allow for IEC and APC cell communication in a context which more closely mimics that which occurs in vivo.

Prognostic role of indoleamine 2,3-dioxygenase 1 expression in solid tumors: A systematic review and meta-analysis

Background

As an emerging immune checkpoint molecule, indoleamine 2,3-dioxygenase 1 (IDO1) is an immunosuppressive rate-limiting enzyme in metabolism of tryptophan to kynurenine. The expression of IDO1 affected the prognosis of patients in cancers by regulating the kynurenine pathway, inhibiting the proliferation of T cells. However, the association between IDO1 and solid tumor prognosis was controversial. To further investigate the role of IDO1 expression in solid tumors, we conducted the systematic review and meta-analysis.

Methods

We searched the Web of Science, PubMed, Embase, and Cochrane Library databases and China National Knowledge Infrastructure (CNKI) to identify studies evaluating the prognostic value of IDO1 in solid tumors. Overall survival (OS), progression-free survival (PFS), and disease-free survival (DFS) were extracted as the outcome. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated by using the fixed-effect/random-effect model, while heterogeneity, publication bias, and sensitivity between studies were also analyzed.

Results

Eighteen studies with 2,168 patients were included in this systematic review and meta-analysis. The results indicated that the high expression of IDO1 was associated with a shorter OS (n = 1926, HR = 1.60, 95% CI: 1.22–2.11, P = 0.001) and DFS (n = 327, HR = 2.65, 95% CI: 1.52–4.63, P = 0.001), while it was uncorrelated with PFS (n = 428, HR = 1.76, 95% CI: 0.99–3.14, P = 0.240). There was significant heterogeneity between studies on OS (I2 = 77.8%, P &lt; 0.001). Subgroup analysis showed that age, gender, tumor type, follow-up period, and study quality were possible reasons for high heterogeneity. The result of the trim-and-fill method indicated that publication bias for OS had no impact on our results. Egger’s test suggested no publication bias for PFS (P = 0.553) and DFS (P = 0.273). Furthermore, sensitivity analysis indicated the result was stable.

Conclusion

High expression of IDO1 was associated with poor clinical outcomes, indicating that it could be a potential prognostic marker in various cancer types.

The Key Clinical Questions of Neoadjuvant Chemoradiotherapy for Resectable Esophageal Cancer—A Review

Over 50% of individuals with esophageal cancer (EC) present with advanced stages of the disease; therefore, their outcome following surgery alone is poor, with only 25%–36% being alive 5 years post-surgery. Based on the evidence that the CROSS and NEOCRTEC5010 trials provided, neoadjuvant chemoradiotherapy (nCRT) is now the standard therapy for patients with locally advanced EC. However, there are still many concerning clinical questions that remain controversial such as radiation dose, appropriate patient selection, the design of the radiation field, the time interval between chemoradiotherapy (CRT) and surgery, and esophageal retention. With immune checkpoint inhibitors (ICIs) rapidly becoming a mainstay of cancer therapy, along with radiation, chemotherapy, and surgery, the combination mode of immunotherapy is also becoming a hot topic of discussion. Here, we try to provide constructive suggestions to answer the perplexing problems and clinical concerns for the progress of nCRT for EC in the future.

A Risk Model Based on Immune-Related Genes Predicts Prognosis and Characterizes the Immune Landscape in Esophageal Cancer

Aberrant immune gene expression has been shown to have close correlations with the occurrence and progression of esophageal cancer (EC). We aimed to generate a prognostic signature based on immune-related genes (IRGs) capable of predicting prognosis, immune checkpoint gene (ICG) expressions, and half-inhibitory concentration (IC₅₀) for chemotherapy agents for EC patients. Transcriptome, clinical, and mutation data on tumorous and paratumorous tissues from EC patients were collected from The Cancer Genome Atlas (TCGA) database. Then, we performed differential analysis to identify IRGs differentially expressed in EC. Their biofunctions and related pathways were explored using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. These gene expression profiling data were merged with survival information and subjected to univariate Cox regression to select prognostic genes, which were then included in a Lasso-Cox model for signature generation (risk score calculation). Patients were divided into the high- and low-risk groups using the median risk score as a cutoff. The accuracy of the signature in overall survival prediction was assessed, so were its performances in predicting ICG expressions and IC₅₀ for chemotherapy and targeted therapy agents and immune cell landscape characterization. Fifteen prognostic IRGs were identified, seven of which were optimal for risk score calculation. As expected, high-risk patients had worse overall survival than low-risk individuals. Significant differences were found in tumor staging, immune cell infiltration degree, frequency of tumor mutations, tumor mutation burden (TMB), and immune checkpoint gene expressions between high- vs. low-risk patients. Further, high-risk patients exhibited high predicted IC₅₀ for paclitaxel, cisplatin, doxorubicin, and erlotinib compared to low-risk patients. The seven-IRG-based signature can independently and accurately predict overall survival and tumor progression, characterize the tumor immune microenvironment (TIME) and estimate ICG expressions and IC₅₀ for antitumor therapies. It shows the potential of guiding personalized treatment for EC patients.

Role of immune escape in different digestive tumours

A counterbalance between immune cells and tumour cells is key to fighting tumours, and immune escape is an important mechanism for the survival of tumour cells in the body. Tumor cells and their cytokines impair the activity of T cells, NK cells, macrophages and other immune cells through various ways, and change the expression of their own surface antigens so as to avoid the clearance of the immune system. Changes in major histocompatibility complex molecules, high expression of programmed death-ligand 1, and the presence of immunosuppressive cells in the tumor microenvironment (TME) are main means by which tumors impair the function of immune cells. During the development of tumours of the digestive system, different mechanisms acting on tumour cells, the TME, and immune cells lead to immune escape and promote tumour progression. In this paper, the mechanisms of immune escape in tumour cells of the digestive system are reviewed to provide a theoretical basis for the immunotherapy of gastrointestinal tumours.

(Neo)adjuvant Chemoradiotherapy is Beneficial to the Long-term Survival of Locally Advanced Esophageal Squamous Cell Carcinoma: A Network Meta-analysis

PURPOSE

To determine the most effective and safest treatment mode for locally advanced resectable esophageal squamous cell carcinoma through a network meta-analysis.

METHOD

A Bayesian model was used for a network meta-analysis comparing the efficacy and safety of surgery alone, neoadjuvant therapy, and adjuvant therapy.

RESULTS

Thirty clinical studies, including thirty-one articles, 4866 patients, were analyzed. Overall survival rate: Adjuvant chemoradiotherapy and neoadjuvant chemoradiotherapy were significantly advantageous over surgery alone [hazard ratio (HR) 0.73, 95% confidence interval (CI) 0.57-0.93; HR 0.75, 95%CI 0.65-0.86]. There was no statistically significant difference between adjuvant chemoradiotherapy and neoadjuvant chemoradiotherapy [HR 0.97, 95%CI 0.75-1.28]. Disease-free survival rate: Compared with surgery alone, neoadjuvant chemoradiotherapy had significant benefits [HR 0.65, 95%CI 0.53-0.78]; adjuvant chemoradiotherapy had similar, but not significant benefits [HR 0.7, 0.95%CI 0.45-1.06]. The difference between neoadjuvant chemoradiotherapy and adjuvant chemoradiotherapy was also not statistically significant [HR 0.94, 0.95%CI 0.61-1.43]. Surgery after neoadjuvant chemoradiotherapy: The R0 resection rate was significantly improved [relative risk (RR) 0.25, 95%CI 0.07-0.86], but the overall postoperative morbidity rate and 30-day postoperative mortality rate tended to increase [RR 1.27, 95%CI 0.8-2.01; RR 1.59, 95%CI 0.7-3.22]. Neither neoadjuvant chemotherapy nor neoadjuvant radiotherapy significantly altered the surgical safety or R0 resection rate.

CONCLUSION

Both neoadjuvant chemoradiotherapy and adjuvant chemoradiotherapy appear to be the best supplements to surgery for locally advanced resectable esophageal squamous cell carcinoma.

Targeted Immunotherapies in Gastrointestinal Cancer: From Molecular Mechanisms to Implications

Gastrointestinal cancer is a leading cause of cancer-related mortality and remains a major challenge for cancer treatment. Despite the combined administration of modern surgical techniques and chemoradiotherapy (CRT), the overall 5-year survival rate of gastrointestinal cancer patients in advanced stage disease is less than 15%, due to rapid disease progression, metastasis, and CRT resistance. A better understanding of the mechanisms underlying cancer progression and optimized treatment strategies for gastrointestinal cancer are urgently needed. With increasing evidence highlighting the protective role of immune responses in cancer initiation and progression, immunotherapy has become a hot research topic in the integrative management of gastrointestinal cancer. Here, an overview of the molecular understanding of colorectal cancer, esophageal cancer and gastric cancer is provided. Subsequently, recently developed immunotherapy strategies, including immune checkpoint inhibitors, chimeric antigen receptor T cell therapies, tumor vaccines and therapies targeting other immune cells, have been described. Finally, the underlying mechanisms, fundamental research and clinical trials of each agent are discussed. Overall, this review summarizes recent advances and future directions for immunotherapy for patients with gastrointestinal malignancies.

Programmed cell death-ligand 1 expression predicts poor treatment response and prognostic value in esophageal squamous cell carcinoma patients without esophagectomy

Research on association between programmed cell death ligand 1 (PD-L1) expression in cancer cells and prognosis of esophageal squamous cell carcinoma (ESCC) has been controversial and has focused on patients with surgical resection. We aimed to investigate impact of PD-L1 on treatment response and prognostic value in ESCC and analyze which subset of patients may benefit from immunotherapy. The PD-L1 expression was evaluated by immunohistochemical analysis in all patients. Stratification analysis was performed according to whether surgery was performed. There were no significant correlations between PD-L1 expression with 3-year overall survival (OS) and progression-free survival (PFS) in 81 ESCC patients. Then stratification analysis was performed. Among these 44 patients without surgery, disease control rate (DCR) in negative PD-L1 expression group (78%) was significantly better than those (42%) in positive PD-L1 expression group (P = 0.032). There were no significant correlations between PD-L1 expression with 3-year OS and PFS in 37 ESCC patients receiving surgery. However, in 44 ESCC patients without surgery, the Kaplan-Meier method showed that 3-year OS and PFS in negative PD-L1 expression group were significantly better than those in positive PD-L1 expression group. In Cox univariate and multivariate model, PD-L1 was an independent prognosticator for inferior OS (p = 0.011; p = 0.017). Our research revealed prognostic role of PD-L1 expression in cancer cells may be variable in different treatment methods. Consequently, PD-L1 may serve as an independent prognostic factor and provide a theoretical basis for combining conventional therapy with immunotherapy targeting PD-L1 to achieve better treatment outcome in ESCC patients without esophagectomy.

Clinicopathological and prognostic values of PD-L1 expression in oesophageal squamous cell carcinoma: a meta-analysis of 31 studies with 5368 patients

Several immune checkpoint inhibitors targeting programmed death ligand 1 (PD-L1)/programmed death 1 have successfully improved the prognosis of oesophageal squamous cell carcinoma (ESCC) with approval in certain countries. However, whether the expression of PD-L1 is associated with the degree of benefit is unclear yet and a unified standard of antibody and cut-off value of PD-L1 detection is also lacking. The current meta-analysis then aimed to explore the association between PD-L1 expression and clinicopathological features as well as prognosis in ESCC.A systematic search on PubMed, Embase, Cochrane Library and Web of Science databases was performed up to 30 March 2021. The correlation between PD-L1 expression and clinicopathological features, as well as prognosis in ESCC, was estimated with the random-effects model.A total of 5368 patients from 31 retrospective studies were enrolled. The overexpression of PD-L1 was significantly associated with lymph node metastasis (OR 1.342, 95% CI 0.995 to 1.809, p=0.050) and distant metastasis (OR 1.516, 95% CI 1.001 to 2.294, p=0.050). The pooled HR showed that PD-L1 overexpression was significantly correlated with poor overall survival (OS) of patients with ESCC (HR 1.306, 95% CI 1.108 to 1.539, p<0.010) but not disease-free survival (DFS) (HR 1.180, 95% CI 0.937 to 1.487, p=0.160). Heterogeneity decreased significantly in subgroup analyses. The overexpression of PD-L1 was associated with poor DFS at the cut-off point of ≥1% (HR 1.642, 95% CI 1.367 to 1.973, p<0.010; I²=0%) and worse OS at the cut-off point of ≥10% (HR 1.575, 95% CI 1.175 to 2.111, p<0.010; I²=0%).The overexpression of PD-L1 was correlated with lymph node and distant metastasis as well as poor survival of ESCC.

IDO1 Expression in Melanoma Metastases Is Low and Associated With Improved Overall Survival

Indoleamine 2-3 dioxygenase 1 (IDO1) expression may contribute to immunologic escape by melanoma metastases. However, a recent clinical trial failed to identify any clinical benefits of IDO1 inhibition in patients with unresectable metastatic melanoma, and prior characterizations of IDO1 expression have predominately studied primary lesions and local metastases, generating uncertainty regarding IDO1 expression in distant metastases. We hypothesized that IDO1 expression in such lesions would be low and correlated with decreased overall survival (OS). Metastases from patients (n=96) with stage IIIb to IV melanoma underwent tissue microarray construction and immunohistochemical staining for IDO1. Th1-related gene expression was determined quantitatively. Associations between OS and IDO1 expression were assessed with multivariate models. Of 96 metastatic lesions, 28% were IDOpos, and 85% exhibited IDO1 expression in <10% of tumor cells. IDOpos lesions were associated with improved OS (28.9 vs. 10.5 mo, P=0.02) and expression of Th1-related genes. OS was not associated with IDO1 expression in a multivariate analysis of all patients; however, IDO1 expression (hazard ratio=0.25, P=0.01) and intratumoral CD8+ T-cell density (hazard ratio=0.99, P<0.01) were correlated with OS in patients who underwent metastasectomy with curative-intent. IDOpos metastases were less likely to recur after metastasectomy (54% vs. 16%, P=0.01). IDO1 expression was low in melanoma metastases and correlated with OS after metastasectomy with curative-intent. Intratumoral CD8+ T cells and Th1-related genes were correlated with IDO1 expression, as was tumor recurrence. These suggest that IDO1 expression may be a marker of immunologic tumor control, and may inform participant selection in future trials of IDO1 inhibitors.

The footprint of kynurenine pathway in every cancer: a new target for chemotherapy

Treatment of cancers has always been a challenge for physicians. Typically, several groups of anti-cancer medications are needed for effective management of an invasive and metastatic cancer. Recently, therapeutic potentiation of immune system markedly improved treatment of cancers. Kynurenine pathway has an interwoven correlation with immune system. Kynurenine promotes T Reg (regulatory) differentiation, which leads to increased production of anti-inflammatory cytokines and suppression of cytotoxic activity of T cells. Overactivation of kynurenine pathway in cancers provides an immunologically susceptible microenvironment for mutant cells to survive and invade surrounding tissues. Interestingly, kynurenine pathway vigorously interacts with other molecular pathways involved in tumorigenesis. For instance, kynurenine pathway interacts with phospoinosisitide-3 kinase (PI3K), extracellular signal-regulated kinase (ERK), Wnt/β-catenin, P53, bridging integrator 1 (BIN-1), cyclooxygenase 2 (COX-2), cyclin-dependent kinase (CDK) and collagen type XII α1 chain (COL12A1). Overactivation of kynurenine pathway, particularly overactivation of indoleamine 2,3-dioxygenase (IDO) predicts poor prognosis of several cancers such as gastrointestinal cancers, gynecological cancers, hematologic malignancies, breast cancer, lung cancer, glioma, melanoma, prostate cancer and pancreatic cancer. Furthermore, kynurenine increases the invasion, metastasis and chemoresistance of cancer cells. Recently, IDO inhibitors entered clinical trials and successfully passed their safety tests and showed promising therapeutic efficacy for cancers such as melanoma, brain cancer, renal cell carcinoma, prostate cancer and pancreatic cancer. However, a phase III trial of epacadostat, an IDO inhibitor, could not increase the efficacy of treatment with pembrolizumab for melanoma. In this review the expanding knowledge towards kynurenine pathway and its application in each cancer is discussed separately.

Prediction of Pathologic Response to Neoadjuvant Chemoradiotherapy in Patients with Esophageal Squamous Cell Carcinoma Incorporating Hematological Biomarkers

PURPOSE

This study aimed to develop a nomogram for predicting pathologic complete response (pCR) after neoadjuvant chemoradiotherapy (CRT) in patients with esophageal squamous cell carcinoma (ESCC) by integrating hematological biomarkers and clinicopathological characteristics.

Materials and Methods

Between 2003 and 2017, 306 ESCC patients who underwent neoadjuvant CRT followed by esophagectomy were analyzed. Besides clinicopathological factors, hematological parameters before, during, and after CRT were collected. Univariate and multivariate logistic regression analyses were performed to identify predictive factors for pCR. A nomogram model was built and internally validated.

RESULTS

Absolute lymphocyte count (ALC), lymphocyte to monocyte ratio, albumin, hemoglobin, white blood cell, neutrophil, and platelet count generally declined, whereas neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) increased significantly following neoadjuvant CRT. After surgery, 124 patients (40.5%) achieved a pCR. The pCR group demonstrated significantly more favorable survival than the non-pCR group. On multivariate analysis, significant factors associated with pCR included sex, chemotherapy regimen, post-CRT endoscopic finding, pre-CRT NLR, ALC nadir during CRT, and post-CRT PLR, which were incorporated into the prediction model. The nomogram indicated good accuracy in predicting pCR, with a C-index of 0.75 (95% confidence interval, 0.71 to 0.78).

CONCLUSION

Female, chemotherapy regimen of cisplatin/vinorelbine, negative post-CRT endoscopic finding, pre-CRT NLR (≤ 2.1), ALC nadir during CRT (> 0.35 ×109/L), and post-CRT PLR (≤ 83.0) were significantly associated with pCR in ESCC patients treated with neoadjuvant CRT. A nomogram incorporating hematological biomarkers to predict pCR was developed and internally validated, showing good predictive performance.

An individualized immune signature of pretreatment biopsies predicts pathological complete response to neoadjuvant chemoradiotherapy and outcomes in patients with esophageal squamous cell carcinoma

No clinically available biomarkers can predict pathological complete response (pCR) for esophageal squamous cell carcinomas (ESCCs) with neoadjuvant chemoradiotherapy (nCRT). Considering that antitumor immunity status is an important determinant for nCRT, we performed an integrative analysis of immune-related gene profiles from pretreatment biopsies and constructed the first individualized immune signature for pCR and outcome prediction of ESCCs through a multicenter analysis. During the discovery phase, 14 differentially expressed immune-related genes (DEIGs) with greater than a twofold change between pCRs and less than pCRs (<pCRs) were revealed from 28 pretreatment tumors in a Guangzhou cohort using microarray data. Ten DEIGs were verified by qPCR from 30 cases in a Beijing discovery cohort. Then, a four-gene-based immune signature (SERPINE1, MMP12, PLAUR, and EPS8) was built based on the verified DEIGs from 71 cases in a Beijing training cohort, and achieved a high accuracy with an area under the receiver operating characteristic curve (AUC) of 0.970. The signature was further validated in an internal validation cohort and an integrated external cohort (Zhengzhou and Anyang cohorts) with AUCs of 0.890 and 0.859, respectively. Importantly, a multivariate analysis showed that the signature was the only independent predictor for pCR. In addition, patients with high predictive scores showed significantly longer overall and relapse-free survival across multiple centers (P < 0.05). This is the first, validated, and clinically applicable individualized immune signature of pCR and outcome prediction for ESCCs with nCRT. Further prospective validation may facilitate the combination of nCRT and immunotherapy.

IDO1 Expression Increased After Neoadjuvant Therapy Predicts Poor Pathologic Response and Prognosis in Esophageal Squamous Cell Carcinoma

Indoleamine 2,3-dioxygenase (IDO1) plays an important role in tumor immune evasion. In this study, we investigated the changes of tumor IDO1 expression and CD8+ tumor-infiltrating lymphocytes (TILs) status in tumor microenvironment (TME) after neoadjuvant chemoradiotherapy (NCRT) or neoadjuvant chemotherapy (NCT) in esophageal squamous cell carcinoma (ESCC), respectively. Moreover, the potential predictive value of the changes of tumor IDO1 expression and CD8+TILs status on pathologic response and clinical outcome was further evaluated. By matching propensity scores in 295 patients, a total of 85 ESCC patients with neoadjuvant therapy followed by surgery were recruited, including 17 patients with NCRT and 68 patients with NCT. Tumor IDO1 expression and CD8+TILs within TME in paired specimens were evaluated by immunohistochemistry, and the changes of tumor IDO1 expression and CD8+TILs between the paired specimens were estimated. Tumor IDO1 expression significantly increased from baseline to postoperative tumor tissue after NCT (p = 0.002), whereas no significant difference was detected after NCRT (p = 0.44). The density of CD8+TILs in the tumor-invasive margin increased significantly after neoadjuvant therapy, and there was no significant difference in density changes of CD8+TILs between the NCRT and NCT groups (p = 0.118). Upregulation of tumor IDO1 expression after neoadjuvant therapy was associated with poor pathologic response (p = 0.002). Lastly, multivariate Cox analysis showed that IDO1-rise patients after neoadjuvant therapy were related to poor prognosis (p = 0.047). These results indicated that chemotherapy could promote tumor IDO1 expression, and the increased tumor IDO1 expression after neoadjuvant therapy predicted poor pathologic response and prognosis in ESCC.

Lymphocyte-monocyte ratio as a predictive marker for pathological complete response to neoadjuvant therapy in esophageal squamous cell carcinoma

Background

The hematological markers of systemic inflammation has been proved to be significantly associated with clinical outcomes in esophageal cancer. This retrospectively study was to evaluate the value of the hematological markers in predicting pathological complete response (pCR) and overall survival (OS) in patients with locally advanced esophageal squamous cell carcinoma (LA-ESCC) who received neoadjuvant chemoradiotherapy (nCRT).

Methods

A total of 87 patients with newly diagnosed LA-ESCC were retrospectively analyzed. The pretreatment lymphocyte-monocyte ratio (LMR), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII) were selected as hematological markers.

Results

After nCRT, 26 (29.9%) patients achieved pCR and 61 (70.1%) patients had non-pCR. The LMR was significantly higher in patients who achieved pCR compared to that in patients who did not achieve pCR (4.35±1.68 vs. 3.33±1.13, P=0.002). Based on the receiver operating characteristic (ROC) curve, the optimal cut off value of LMR that predicted pCR was 3.73 [area under the curve: 0.712; 95% confidence interval (CI): 0.594–0.830; P=0.002], with a sensitivity of 65.4% and specificity of 77.0%. The pCR rate of patients with LMR ≥3.73 was 53.1%, while the pCR rate of patients with LMR <3.73 was only 16.4% (P<0.001). The univariate and multivariate logistic regression analysis confirmed that LMR was an independent predictor of pCR [odds ratio: 5.093; 95% CI: 1.658–15.646; P=0.004]. However, in the prediction of OS, a multivariate Cox proportional hazard model revealed that only clinical stage [hazard ratio (HR): 1.970; 95% CI: 1.144–3.391; P=0.014] and pCR (HR: 0.469; 95% CI: 0.237–0.928; P=0.030) were independent prognostic factors.

Conclusions

Pre-treatment LMR may predict pCR in LA-ESCC patients who were treated with nCRT. Having pCR is an independent prognostic factor for prolonged survival.

The prognostic value of IDO expression in solid tumors: a systematic review and meta-analysis

Background

Indoleamine 2,3-dioxygenase (IDO) is a rate-limiting enzyme in the metabolism of tryptophan into kynurenine. It is considered to be an immunosuppressive molecule that plays an important role in the development of tumors. However, the association between IDO and solid tumor prognosis remains unclear. Herein, we retrieved relevant published literature and analyzed the association between IDO expression and prognosis in solid tumors.

Methods

Studies related to IDO expression and tumor prognosis were retrieved using PMC, EMbase and web of science database. Overall survival (OS), time to tumor progression (TTP) and other data in each study were extracted. Hazard ratio (HR) was used for analysis and calculation, while heterogeneity and publication bias between studies were also analyzed.

Results

A total of 31 studies were included in this meta-analysis. Overall, high expression of IDO was significantly associated with poor OS (HR 1.92, 95% CI 1.52–2.43, P < 0.001) and TTP (HR 2.25 95% CI 1.58–3.22, P < 0.001). However, there was significant heterogeneity between studies on OS (I² = 81.1%, P < 0.001) and TTP (I² = 54.8%, P = 0.007). Subgroup analysis showed lower heterogeneity among prospective studies, studies of the same tumor type, and studies with follow-up periods longer than 45 months.

Conclusions

The high expression of IDO was significantly associated with the poor prognosis of solid tumors, suggesting that it can be used as a biomarker for tumor prognosis and as a potential target for tumor therapy.

Immunotherapy and radiation therapy for gastrointestinal malignancies: hope or hype?

Immunotherapy represents the newest pillar in cancer care. Although there are increasing data showing the efficacy of immunotherapy there is a spectrum of response across unselected populations of cancer patients. In fact, response rates can be poor even among patients with immunogenic tumors for reasons that remain poorly understood. A promising clinical strategy to improve outcomes, which is supported by an abundance of preclinical data, is combining immunotherapy with radiation therapy. Here we review the existing evidence and future directions for combining immunotherapy and radiation therapy for patients with gastrointestinal cancers.

C-Myc regulates PD-L1 expression in esophageal squamous cell carcinoma

Immunotherapy using antibodies blocking the programmed cell death 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) pathway has achieved great success in preclinical models and the clinical treatment of esophageal squamous cell carcinoma (ESCC). The c-Myc proto-oncogene helps prevent immune cells from attacking tumor cells by inducing PD-L1 expression. However, the underlying mechanisms of c-Myc and PD-L1 in ESCC remain unclear, and a thorough understanding of this regulation would allow the development of new approaches to enhance antitumor immunity. In the present study, the positive relationship between c-Myc and PD-L1 was explored in the Cancer Genome Atlas dataset using the bioinformatics tool GEPIA, and was confirmed in 105 ESCC tissues by immunostaining (r=0.516, P<0.001). The patients positive for both proteins had a poorer overall survival (P=0.032). Furthermore, in ESCC cell lines, c-Myc overexpression, depletion, and inhibition was able to regulate the expression of PD-L1. Also, the ChIP assays showed that the increase in PD-L1 expression was likely due to the binding of c-Myc to the PD-L1 promoter. Taken together, c-Myc and PD-L1 levels were significantly correlated, and c-Myc expression regulated the expression of PD-L1 in ESCC cells. In addition, a small molecule inhibitor of c-Myc effectively regulated PD-L1 expression. This indicates that synergistic therapy combining a c-Myc inhibitor with PD-L1 immunotherapy might be a promising new treatment strategy for ESCC.

Predictive biomarkers and mechanisms underlying resistance to PD1/PD-L1 blockade cancer immunotherapy

Immune checkpoint blockade targeting PD-1/PD-L1 has promising therapeutic efficacy in a variety of tumors, but resistance during treatment is a major issue. In this review, we describe the utility of PD-L1 expression levels, mutation burden, immune cell infiltration, and immune cell function for predicting the efficacy of PD-1/PD-L1 blockade therapy. Furthermore, we explore the mechanisms underlying immunotherapy resistance caused by PD-L1 expression on tumor cells, T cell dysfunction, and T cell exhaustion. Based on these mechanisms, we propose combination therapeutic strategies. We emphasize the importance of patient-specific treatment plans to reduce the economic burden and prolong the life of patients. The predictive indicators, resistance mechanisms, and combination therapies described in this review provide a basis for improved precision medicine.

Changes in Indoleamine 2,3-Dioxygenase 1 Expression and CD8+ Tumor-Infiltrating Lymphocytes after Neoadjuvant Chemoradiation Therapy and Prognostic Significance in Esophageal Squamous Cell Carcinoma

PURPOSE

Despite good preclinical evidence, clinical data on the effect of neoadjuvant chemoradiation therapy (CRT) on expression of immune markers in esophageal cancer are limited. This study aimed to evaluate the changes in indoleamine 2,3-dioxygenase 1 (IDO1) expression, programmed cell death-ligand 1 (PD-L1) expression, and CD8+ tumor-infiltrating lymphocyte status after neoadjuvant CRT and the prognostic significance in esophageal squamous cell carcinoma (ESCC).

METHODS AND MATERIALS

Between 2003 and 2017, 138 patients with ESCC who underwent neoadjuvant CRT and esophagectomy without achieving pathologic complete response were included for analysis. Both pre-CRT biopsies and post-CRT surgical specimens were available in 82 patients. Immunohistochemistry of IDO1, PD-L1, and CD8 density were analyzed.

RESULTS

Among 82 paired samples, the expression levels of IDO1 and PD-L1 and CD8 density increased significantly after neoadjuvant CRT (P < .01 for all). Patients with high IDO1 expression after CRT had poorer overall survival (P = .001) and recurrence-free survival (P < .001) than those with low IDO1 expression. High post-CRT CD8 density was significantly correlated with more favorable overall survival (P = .01) and recurrence-free survival (P = .008). Neither pre- nor post-CRT PD-L1 expression was an independent prognostic factor for survival. Stratification analysis revealed that patients with combined low IDO1 expression and high CD8 density after CRT were significantly associated with better survival than other subgroups. The major findings were reproducible in an independent validation cohort.

CONCLUSIONS

IDO1 and PD-L1 expression and CD8 density increased significantly after neoadjuvant CRT in ESCC. The post-CRT IDO1 expression and CD8 density could serve as prognostic biomarkers for survival.

The immune landscape of esophageal cancer

Esophageal cancer (EC) seriously threatens human health, and a promising new avenue for EC treatment involves cancer immunotherapy. To improve the efficacy of EC immunotherapy and to develop novel strategies for EC prognosis prediction or clinical treatment, understanding the immune landscapes in EC is required. EC cells harbor abundant tumor antigens, including tumor-associated antigens and neoantigens, which have the ability to initiate dendritic cell-mediated tumor-killing cytotoxic T lymphocytes in the early stage of cancer development. As EC cells battle the immune system, they obtain an ability to suppress antitumor immunity through immune checkpoints, secreted factors, and negative regulatory immune cells. Cancer-associated fibroblasts also contribute to the immune evasion of EC cells. Some factors of the immune landscape in EC tumor microenvironment are associated with cancer development, patient survival, or treatment response. Based on the immune landscape, peptide vaccines, adoptive T cell therapy, and immune checkpoint blockade can be used for EC immunotherapy. Combined strategies are required for better clinical outcome in EC. This review provides directions to design novel and effective strategies for prognosis prediction and immunotherapy in EC.