Cytotoxic T lymphocyte antigen-4 expression in esophageal carcinoma: implications for prognosis

An extensive immunohistochemical analysis of 290 ovarian adult granulosa cell tumors with 29 markers

The current knowledge about the immunohistochemical features of adult granulosa cell tumor (AGCT) is mostly limited to the "traditional" immunohistochemical markers of sex cord differentiation, such as inhibin, calretinin, FOXL2, SF1, and CD99. Knowledge about the immunohistochemical markers possibly used for predictive purpose is limited. In our study, we focused on the immunohistochemical examination of 290 cases of AGCT classified based on strict diagnostic criteria, including molecular testing. The antibodies used included 12 of the "diagnostic" antibodies already examined in previous studies, 10 antibodies whose expression has not yet been examined in AGCT, and 7 antibodies with possible predictive significance, including the expression of HER2, PD-L1, CTLA4, and 4 mismatch repair (MMR) proteins. The results of our study showed expression of FOXL2, SF1, CD99, inhibin A, calretinin, ER, PR, AR, CKAE1/3, and CAIX in 98%, 100%, 90%, 78%, 45%, 41%, 94%, 82%, 26%, and 9% of AGCT, respectively. GATA3, SATB2, napsin A, MUC4, TTF1, and CD44 were all negative. PTEN showed a loss of expression in 71% of cases and DPC4 in 4% of cases. The aberrant staining pattern (overexpression) of p53 was found in 1% (3/268) of cases, 2 primary tumors, and 1 recurrent case. Concerning the predictive markers, the results of our study showed that AGCT is microsatellite stable, do not express PD-L1, and are HER2 negative. The CTLA4 expression was found in almost 70% of AGCT tumor cells.

Identification of Two Distinct Immune Subtypes in Hepatitis B Virus (HBV)-Associated Hepatocellular Carcinoma (HCC)

HBV is the most common risk factor for HCC development, accounting for almost 50% of cases worldwide. Despite significant advances in immunotherapy, there is limited information on the HBV-HCC tumor microenvironment (TME), which may influence the response to checkpoint inhibitors. Here, we characterize the TME in a unique series of liver specimens from HBV-HCC patients to identify who might benefit from immunotherapy. By combining an extensive immunohistochemistry analysis with the transcriptomic profile of paired liver samples (tumor vs. nontumorous tissue) from 12 well-characterized Caucasian patients with HBV-HCC, we identified two distinct tumor subtypes that we defined immune-high and immune-low. The immune-high subtype, seen in half of the patients, is characterized by a high number of infiltrating B and T cells in association with stromal activation and a transcriptomic profile featuring inhibition of antigen presentation and CTL activation. All the immune-high tumors expressed high levels of CTLA-4 and low levels of PD-1, while PD-L1 was present only in four of six cases. In contrast, the immune-low subtype shows significantly lower lymphocyte infiltration and stromal activation. By whole exome sequencing, we documented that four out of six individuals with the immune-low subtype had missense mutations in the CTNNB1 gene, while only one patient had mutations in this gene in the immune-high subtype. Outside the tumor, there were no differences between the two subtypes. This study identifies two distinctive immune subtypes in HBV-associated HCC, regardless of the microenvironment observed in the surrounding nontumorous tissue, providing new insights into pathogenesis. These findings may be instrumental in the identification of patients who might benefit from immunotherapy.

Role of CTLA4 and pSTAT3 Immunostaining in Prognosis and Treatment of the Colorectal Carcinoma

Background & Objective

Colorectal carcinoma (CRC) is the third leading cause of cancer-caused death worldwide and constitutes about 6.48% of all malignancies in Egypt. Studying the molecular profile of CRC is essential for developing targeted therapies. STAT3 and CTLA4 expression are considered as molecular abnormalities involved in the CRC progression and chemo-resistance. Therefore, they could be used as potential therapeutic targets. This study aimed to evaluate pSTAT3 and CTLA4 expression levels and their possible roles as prognostic and predictive biomarkers in CRC using immunohistochemistry (IHC).

Methods

This retrospective study included 113 CRC patients. Tissue microarrays were constructed, followed by pSTAT3 and CTLA4 antibodies immunostaining. Their expression was assessed and compared with the clinicopathological parameters and survival data.

Results

Both pSTAT3 and CTLA4 overexpression were significantly associated with poor prognostic parameters, such as the presence of distant metastasis (P=0.02 & 0.03), high grade (P<0.001 & 0.03), high mitotic count (P<0.001 & 0.03), high tumor budding group (P=0.008 & 0.04), infiltrating tumor border (P<0.001 & 0.007) respectively, and advanced pathological stage with pSTAT3 (P=0.02). A significant association was found between overexpression of both markers and short overall survival. Correlations between the H-score of pSTAT3 and CTLA4 in CRC showed a significant positive correlation (P<0.001).

Conclusion

STAT3 and CTLA4 positivity may be linked to the development and progression of the CRC, and they may provide potential prognostic indicators and therapeutic targets for CRC patients.

Immune Escape Strategies in Head and Neck Cancer: Evade, Resist, Inhibit, Recruit

Head and neck cancers (HNCs) arise from the mucosal lining of the aerodigestive tract and are often associated with alcohol use, tobacco use, and/or human papillomavirus (HPV) infection. Over 600,000 new cases of HNC are diagnosed each year, making it the sixth most common cancer worldwide. Historically, treatments have included surgery, radiation, and chemotherapy, and while these treatments are still the backbone of current therapy, several immunotherapies have recently been approved by the Food and Drug Administration (FDA) for use in HNC. The role of the immune system in tumorigenesis and cancer progression has been explored since the early 20th century, eventually coalescing into the current three-phase model of cancer immunoediting. During each of the three phases-elimination, equilibrium, and escape-cancer cells develop and utilize multiple strategies to either reach or remain in the final phase, escape, at which point the tumor is able to grow and metastasize with little to no detrimental interference from the immune system. In this review, we summarize the many strategies used by HNC to escape the immune system, which include ways to evade immune detection, resist immune cell attacks, inhibit immune cell functions, and recruit pro-tumor immune cells.

Systemic treatments for resectable carcinoma of the esophagus

One of the most prevalent malignancies in the world is esophageal cancer (EC). The 5-year survival rate of EC remains pitiful despite treatment advancements. Neoadjuvant chemoradiotherapy in conjunction with esophagectomy is the standard of care for patients with resectable disease. The pathological complete response rate, however, is not acceptable. A distant metastasis or a locoregional recurrence will occur in about half of the patients. To increase the clinical effectiveness of therapy, it is consequently vital to investigate cutting-edge and potent therapeutic modalities. The approach to the management of resectable EC using immunotherapy has been considerably altered by immune checkpoint inhibitors. Systemic immunotherapy has recently been shown to have the potential to increase the survival of patients with resectable EC, according to growing clinical data. A combination of chemotherapy, radiation, and immunotherapy may have a synergistic antitumor impact because, according to mounting evidence, these treatments can stimulate the immune system via a number of different pathways. In light of this, it makes sense to consider the value of neoadjuvant immunotherapy for patients with surgically treatable EC. In this review, we clarify the rationale for neoadjuvant immunotherapy in resectable EC patients, recap the clinical outcomes of these approaches, go through the upcoming and ongoing investigations, and emphasize the difficulties and unmet research requirements.

CTLA-4 and its inhibitors in esophageal cancer: efficacy of therapy and potential mechanisms of adverse events

Esophageal cancer is one of the most prevalent diseases in the world, and its prognosis remains poor. Surgery, chemotherapy, and radiotherapy are the most common treatment strategies for esophageal cancer. Although these conventional treatment methods are sometimes beneficial, patients with esophageal cancer still have a high risk of local relapse and metastasis. Thus, novel and effective therapies are needed. Immune checkpoint inhibitors are a type of immunotherapy being studied as a treatment for patients with advanced cancers, and strategies using such inhibitors have rapidly progressed to be recognized as transformative treatments for various cancers in recent years. Immune checkpoint inhibitors combined with chemotherapy or radiotherapy have become the first-line and second-line treatment strategies for advanced esophageal cancer. In addition, immune checkpoint inhibitors have also been recognized as another option for patients with terminal esophageal cancer who cannot benefit from chemotherapy, and they even have potential benefits as a novel neoadjuvant treatment option for locally advanced esophageal cancer. Currently, there are two types of immune checkpoint inhibitors commonly applied in clinical practice: immune checkpoint inhibitors targeting programmed death 1/programmed cell death ligand 1 and immune checkpoint inhibitors targeting cytotoxic T-lymphocyte-associated protein 4. However, cytotoxic T-lymphocyte-associated protein 4 immune checkpoint inhibitors are rarely used compared with programmed death 1/programmed cell death ligand 1 inhibitors in esophageal cancer and other cancers, and the clinical benefit is unclear. We analyzed and summarized the efficacy and safety of cytotoxic T-lymphocyte-associated protein 4 immune checkpoint inhibitors in the treatment of esophageal cancer. Due to the lack of clinical applications, it is expected that cytotoxic T-lymphocyte-associated protein 4 immune checkpoint inhibitors in combination with other treatments may provide superior benefits and improve the prognosis of patients with esophageal cancer.

CTLA4 DNA methylation is associated with CTLA-4 expression and predicts response to immunotherapy in head and neck squamous cell carcinoma

BACKGROUND

The majority of patients with recurrent or metastasized head and neck squamous cell carcinoma (HNSCC) do not benefit from immune checkpoint blockade (ICB) while several patients experience severe and persistent immune-mediated side effects. Therefore, predictive biomarkers are urgently needed to allow for a personalized treatment. In this study, we investigated DNA methylation of the immune checkpoint gene CTLA4 with regard to its predictive value.

METHODS

We analyzed CTLA4 promoter methylation in tumors of HNSCC patients (N = 29) treated with ICB at the University Medical Center Bonn with regard to response to ICB and progression-free survival. We further analyzed a second cohort (N = 138) of patients that did not receive ICB with regard to CTLA4 promoter methylation, CTLA-4 protein expression, and immune cell infiltrates. Finally, we tested inducibility of CTLA-4 protein expression in HNSCC cells using the DNA methyltransferase inhibitor decitabine.

RESULTS

Lower CTLA4 promoter methylation correlated with response to ICB and prolonged progression-free survival. We could show that not only tumor infiltrating immune cells, but also HNSCC cells harbor cytoplasmic and nuclear CTLA-4 expression. CTLA4 promoter methylation inversely correlated with infiltrates of CD3+, CD4+, CD8+, and CD45+ immune cells. CTLA4 methylation did not correlate with protein expression in tumors, however, decitabine treatment led to decreased CTLA4 methylation and an induction of CTLA4 mRNA and CTLA-4 protein expression in HNSCC cell lines.

CONCLUSIONS

Our results indicate that CTLA4 DNA hypomethylation is a predictive biomarker for response to ICB in HNSCC. Our study warrants further analyses of the predictive value of CTLA4 DNA methylation in clinical trials of anti-PD-1 and/or anti-CTLA-4 immunotherapy in HNSCC.

Treatments for resectable esophageal cancer: from traditional systemic therapy to immunotherapy

ABSTRACT

Esophageal cancer (EC) has a high incidence and poor prognosis. The two major histological types, squamous cell carcinoma and adenocarcinoma, differ in their epidemiology and treatment options. Patients with locally advanced EC benefit from multimodal therapy concepts including neoadjuvant chemotherapy, neoadjuvant chemoradiotherapy, and perioperative chemotherapy. Currently, immunotherapy for the solid tumor is a hot spot. Treatment with adjuvant immune checkpoint inhibitors (ICIs) is the first immunotherapy for resectable EC listed in the latest National Comprehensive Cancer Network Guidelines for the Esophageal and Esophagogastric Junction Cancers. Recent clinical trials have established ICIs for three treatment models of resectable EC. Their short-term results demonstrated ideal efficacy and tolerable toxicity, though some concerns remain. This review summarizes the novel data on the ICIs for resectable EC and lists the registered related clinical trials. Hopefully, this review can provide a reference for ongoing research on the treatment options for resectable EC.

Expression of immune checkpoint regulators, programmed death-ligand 1 (PD-L1/PD-1), cytotoxic T lymphocyte antigen 4 (CTLA-4), and indolaimine-2, 3-deoxygenase (IDO) in uterine mesenchymal tumors

BACKGROUND

Immune checkpoints including programmed death-ligand 1/programmed death-1/ (PD-L1/PD-1), cytotoxic T lymphocyte antigen 4 (CTLA-4), and indolaimine-2, 3-deoxygenase (IDO) have recently emerged as effective candidates for treatment against a range of human malignancies. We have investigated their expression in the uterine mesenchymal tumors.

METHODS

Sixty-eight mesenchymal tumors were categorized into 6 diagnostic groups. We assessed PD-L1, PD-1, CTLA-4, and IDO expression on paraffin embedded tissue blocks of the uterine tumors using the respective antibodies. Immunohistochemical (IHC) stains were classified as positive when the reactions were present in at least 1% of the cell membranes for PD-L1/PD-1 or in cytoplasm for CTLA-4 and IDO, regardless of intensity. Student's t-test and McNemar's chi-square tests were carried out to analyze the results.

RESULTS

The mesenchymal neoplasms had expressed the immune checkpoints in the tumor and/or the lymphoid cells at the rate of 49% and 54% respectively. The tumor cells were positive in 10 (18%, PD-L1), 0 (0%, PD-1), 18 (32%, CTLA-4), and 13 (23%, IDO) cases while the infiltrating lymphoid cells were positive in 10 (18%, PD-L1), 23 (40%, PD-1), 18 (32%, CTLA-4), and 13 (23%, IDO) cases. Overall, comparison of paired tumor vs lymphoid cells resulted in p-values of ≤ 0.04.

CONCLUSIONS

Nearly 50% of the uterine tumors express at least one of the immune checkpoints in tumor and/or the infiltrating lymphoid cells. However, expression of the proteins in the two cellular components are mutually exclusive. Namely, when tumor cells express an immune checkpoint, the infiltrating lymphoid cells do not, and vice versa. Since the leiomyosarcomas are reportedly resistant to the immunotherapy when PD-L1 is expressed in the tumor cells, it can be posited that presence of the IHC positive lymphoid cells may be a better indicator of response to the treatment.

Immunotherapy resistance in esophageal cancer: Possible mechanisms and clinical implications

Esophageal cancer (EC) is a common malignant gastrointestinal (GI) cancer in adults. Although surgical technology combined with neoadjuvant chemoradiotherapy has advanced rapidly, patients with EC are often diagnosed at an advanced stage and the five-year survival rate remains unsatisfactory. The poor prognosis and high mortality in patients with EC indicate that effective and validated therapy is of great necessity. Recently, immunotherapy has been successfully used in the clinic as a novel therapy for treating solid tumors, bringing new hope to cancer patients. Several immunotherapies, such as immune checkpoint inhibitors (ICIs), chimeric antigen receptor T-cell therapy, and tumor vaccines, have achieved significant breakthroughs in EC treatment. However, the overall response rate (ORR) of immunotherapy in patients with EC is lower than 30%, and most patients initially treated with immunotherapy are likely to develop acquired resistance (AR) over time. Immunosuppression greatly weakens the durability and efficiency of immunotherapy. Because of the heterogeneity within the immune microenvironment and the highly disparate oncological characteristics in different EC individuals, the exact mechanism of immunotherapy resistance in EC remains elusive. In this review, we provide an overview of immunotherapy resistance in EC, mainly focusing on current immunotherapies and potential molecular mechanisms underlying immunosuppression and drug resistance in immunotherapy. Additionally, we discuss prospective biomarkers and novel methods for enhancing the effect of immunotherapy to provide a clear insight into EC immunotherapy.

Comprehensive Curative Effect of Targeting PD-1 or Traditional Single-Agent Chemotherapy in Second-Line Therapy for Terminal or Metastatic Esophageal Cancer: A Systematic Review and Meta-Analysis

The number of programmed cell death protein 1 (PD-1) inhibitors is gradually increasing; this study aimed to comprehensively and systematically evaluate the impact of PD-1 inhibitors as second-line therapy for terminal or metastatic esophageal cancer (EC) on patient survival and the occurrence of adverse events. Suitable randomized controlled trials (RCTs) were retrieved from PubMed, Web of Science, Embase, and Cochrane Library databases. Moreover, we searched for conference abstracts from the American Society of Clinical Oncology (ASCO) and the European Society for Medical Oncology (ESMO) to compare the comprehensive curative effects of PD-1 inhibitors or single-agent therapy in terminal or metastatic EC. The primary outcome indicators were overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and disease control rate (DCR). Treatment-related adverse events (TRAEs) were the secondary outcome indicators. We compared the previously mentioned indicators of the two treatment modalities using Stata software (version 12.0). We compared the long-term survival rates of both treatment groups and analyzed the possible factors affecting OS. We selected five RCTs with 2197 patients as study subjects. Compared with conventional single-agent chemotherapy, PD-1 inhibitors greatly improved the patients' OS (HR = 0.77, 95% CI 0.70–0.85, P < 0.001), but PFS (HR = 0.93, 95% CI 0.77–1.12, P=0.431) and DCR (RR = 0.93, 95% CI 0.71–1.22, P=0.609) were not greatly improved. Moreover, PD-1 inhibitors improved ORR (RR = 1.83, 95% CI 1.16–2.89, P=0.009) and decreased TRAEs (RR = 0.76, 95% CI 0.61–0.95, P < 0.001) and serious TRAEs (RR = 0.40, 95% CI 0.32–0.49, P < 0.001). Further analysis demonstrated that OS was affected by age, sex, region, smoking history, and the number of organ and lymph node metastases. Compared with the traditional single chemotherapy drugs, PD-1 inhibitors can achieve higher OS and ORR, fewer and more serious TRAEs, and better efficacy and safety for second-line therapy of terminal or metastatic EC.

Differential regulation of CTLA4 expression through BTK-dependent and independent mechanisms in CLL

Ibrutinib suppresses CLL cell CTLA4 expression in vitro and in vivo.

CTLA4 expression on CLL is regulated by non-BTKs that differ from T-cell CTLA4 regulation.

Cytotoxic T lymphocyte antigen 4 (CTLA4) is a major immune checkpoint and target for cancer immunotherapy. Although originally discovered and primarily studied on T cells, its role on other cell types has also been recognized in recent years. Here we describe an unexpected interaction between ibrutinib (a targeted inhibitor of Bruton tyrosine kinase [BTK]) and CTLA4 expression on malignant chronic lymphocytic leukemia (CLL) cells. Although BTK itself does play a role in CTLA4 expression in CLL, we demonstrate that ibrutinib’s main suppressive effect on CTLA4 protein expression and trafficking occurs through non-BTK targets influenced by this drug. This suppression is not seen in T cells, indicating a different mechanism of CTLA4 regulation in CLL vs T cells. Appreciating this distinct mechanism and the beneficial non-BTK effects of ibrutinib may contribute to understanding the immune benefits of ibrutinib treatment and lead to therapeutic approaches to improve immune function in patients with CLL by suppressing CTLA4 expression.

Current and Future Immunotherapy-Based Treatments for Oesophageal Cancers

Oesophageal cancer is a disease that causes significant morbidity and mortality worldwide, and the prognosis of this condition has hardly improved in the past few years. Standard treatment includes a combination of chemotherapy, radiotherapy and surgery; however, only a proportion of patients go on to treatment intended to cure the disease due to the late presentation of this disease. New treatment options are of utmost importance, and immunotherapy is a new option that has the potential to transform the landscape of this disease. This treatment is developed to act on the changes within the immune system caused by cancer, including checkpoint inhibitors, which have recently shown great promise in the treatment of this disease and have recently been included in the adjuvant treatment of oesophageal cancer in many countries worldwide. This review will outline the mechanisms by which cancer evades the immune system in those diagnosed with oesophageal cancer and will summarize current and ongoing trials that focus on the use of our own immune system to combat disease.

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.

The effects of immune checkpoint modulators on the clinical course of patients with resectable hepatocellular carcinoma

Background/Aim

Immune checkpoint proteins regulating T-cell mediated anti-tumor immunity have been reported to affect clinical outcomes in multiple malignancies. This study aimed to investigate the prognostic effect of histological expression of immune checkpoint proteins in patients with resected hepatocellular carcinoma (HCC).

Methods

A total of 221 patients with HCC who underwent curative resection were included. Expression of programmed-cell death ligand-1 (PD-L1) in tumor cells (tPD-L1) and tumor infiltrating mononuclear cells (TIMCs) (iPD-L1), programmed-cell death-1 in TIMCs (iPD-1), and cytotoxic T lymphocyte antigen-4 in TIMCs (iCTLA-4) were measured immunohistochemically.

Results

Histo-positivity for iCTLA-4, iPD-1, iPD-L1, and tPD-L1 was 32.1%, 42.5%, 35.3%, and 14.9%, respectively. Multivariate logistic analyses revealed that male sex and tumor >5 cm were variables related to iCTLA-4 positivity (odds ratio [OR], 0.46 and 1.94, respectively; P<0.05). Poor differentiation was related to PD-L1 expression in both tumor cells and TIMCs (OR, 2.88 and 3.46, respectively; P<0.05). Microvascular invasion was significantly associated only with iPD-L1 (OR, 2.24; P<0.05). In time-dependent outcome analyses, expression of immune checkpoint proteins in TIMCs (i.e., iCTLA-4, iPD-1, and iPD-L1) was significantly related to longer overall survival and non-cancer-related survival (all P<0.05), but not to time-to-recurrence or cancer-specific deaths. Concurrent activation of the PD-1:PD-L1 and CTLA-4 pathways predicted improved outcomes in terms of overall survival and non-cancer related survival (P=0.06 and P=0.03, respectively).

Conclusions

Immune checkpoint proteins upregulated in TIMCs in HCC tissues have individual and additive effects in prolonging the survival of patients, specifically in terms of survival not related to cancer recurrence.

Prognostic Implications of Immune Infiltrates in the Breast Cancer Microenvironment: The Role of Expressions of CTLA-4, PD-1, and LAG-3

The assessment of immune infiltrate in invasive breast carcinomas (IBCs), most commonly referred to as tumor infiltrating lymphocytes (TILs), is gaining importance in the current quest for optimal biomarker selection and prediction of prognosis. In this study, the impact of intensity of TILs and expressions of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death-1 (PD-1), and lymphocyte activation gene 3 (LAG-3) in a group of breast carcinomas with regards to the prognosis and conventional pathologic parameters was scrutinized. For this purpose, 238 patients with IBCs containing different proportions of TILs were included in the study. IBCs with higher proportion of TILs were usually grade III carcinomas and correlated with poor prognostic features like receptor negativity, nonluminal intrinsic subtype (P<0.001). Similarly, PD-1 and LAG-3 positivity in immune cells (IC) were more likely to be positive in grade III IBC cases (P=0.004). In addition, PD-1 positivity in IC was more frequent in estrogen receptor-negative tumors (P=0.011) whereas LAG-3 positivity increased in large sized, estrogen receptor and progesterone receptor-negative tumors (P=0.050, 0.023, 0.04, respectively). CTLA-4 positivity in IC was more frequent in large-sized tumors (P=0.040). These 3 markers were also significantly associated with one another and also with the amount of TILs. In survival analysis, cases with prominent-TILs especially displaying CTLA-4, PD-1, and LAG-3 positivity appeared to have longer disease-free and overall survival (CTLA-4: P=0.027, P=0.024; PD-1: P=0.030, P=0.026; LAG-3: P=0.006, P=0.012, respectively). We conclude that the high proportion of TILs and as well as high expression of CTLA-4, PD-1, and LAG-3 in TILs have positively contributed to the outcome despite their correlation with poor conventional pathologic features. We suggest that these 3 immune markers can be used for the determination of proper treatment as well as prediction of prognosis in IBCs with TILs.

Immunological and Metabolic Alterations in Esophageal Cancer

Esophageal cancer is one of the most common types of gastrointestinal malignancies that is encountered. It has a global distribution and affects males and females and is linked to significant morbidity and mortality. The mechanisms underlying pathophysiology are multifactorial and involve the interaction of genetic and environmental factors. This review article describes the immunological and metabolic changes that occur in malignancy of the esophagus.

Semi-automated validation and quantification of CTLA-4 in 90 different tumor entities using multiple antibodies and artificial intelligence

CTLA-4 is an inhibitory immune checkpoint receptor and a negative regulator of anti-tumor T-cell function. This study is aimed for a comparative analysis of CTLA-4⁺ cells between different tumor entities. To quantify CTLA-4⁺ cells, 4582 tumor samples from 90 different tumor entities as well as 608 samples of 76 different normal tissue types were analyzed by immunohistochemistry in a tissue microarray format. Two different antibody clones (MSVA-152R and CAL49) were validated and quantified using a deep learning framework for automated exclusion of unspecific immunostaining. Comparing both CTLA-4 antibodies revealed a clone dependent unspecific staining pattern in adrenal cortical adenoma (63%) for MSVA-152R and in pheochromocytoma (67%) as well as hepatocellular carcinoma (36%) for CAL49. After automated exclusion of non-specific staining reaction (3.6%), a strong correlation was observed for the densities of CTLA-4⁺ lymphocytes obtained by both antibodies (r = 0.87; p < 0.0001). A high CTLA-4⁺ cell density was linked to low pT category (p < 0.0001), absent lymph node metastases (p = 0.0354), and PD-L1 expression in tumor cells or inflammatory cells (p < 0.0001 each). A high CTLA-4/CD3-ratio was linked to absent lymph node metastases (p = 0.0295) and to PD-L1 positivity on immune cells (p = 0.0026). Marked differences exist in the number of CTLA-4⁺ lymphocytes between tumors. Analyzing two independent antibodies by a deep learning framework can facilitate automated quantification of immunohistochemically analyzed target proteins such as CTLA-4.

Cytotoxic T-lymphocyte-associated protein 4 in gastric cancer: Prognosis and association with PD-L1 expression

BACKGROUND

Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is one of the most studied immune checkpoint in gastric cancer (GC). However, the prognostic role of CTLA-4 expression in GC is poorly described. This study aimed to evaluate CTLA-4 expression in GC and its impact on survival, including patients treated with standard platinum-based chemotherapy (CMT), and association with PD-L1 expression.

METHODS

All GC patients who underwent D2-gastrectomy were investigated retrospectively. Tumor samples were examined for CTLA-4 and PD-L1 by immunohistochemistry. Tumor-infiltrating inflammatory cells, including CD4 + and CD8 + , were also examined.

RESULTS

Among the 284 GC patients included, 159 (56%) were CTLA-4 positive and the remaining 125 (44%) were classified as negative. CTLA-4 positive GC was associated with increased inflammatory cell infiltration (p < 0.001), high CD8 + T cells (p = 0.016) and PD-L1 expression (p = 0.026). Considering GC referred for treatment, CTLA-4 negative patients who received CMT had a significant improvement in disease-free survival compared to untreated CLTA-4 negative (p = 0.028). In multivariate analysis, GC positive for both CTLA-4 and PD-L1 had a prognostic impact on survival.

CONCLUSION

CTLA-4 positive was associated with PD-L1 expression and a high tumor-infiltrating CD8 + T cells. Accordingly, positivity for both CTLA-4 and PD-L1 was an independent factor associated to better survival in GC patients.

Advances and challenges in the treatment of esophageal cancer

Esophageal cancer (EC) is one of the most common cancers with high morbidity and mortality rates. EC includes two histological subtypes, namely esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC). ESCC primarily occurs in East Asia, whereas EAC occurs in Western countries. The currently available treatment strategies for EC include surgery, chemotherapy, radiation therapy, molecular targeted therapy, and combinations thereof. However, the prognosis remains poor, and the overall five-year survival rate is very low. Therefore, achieving the goal of effective treatment remains challenging. In this review, we discuss the latest developments in chemotherapy and molecular targeted therapy for EC, and comprehensively analyze the application prospects and existing problems of immunotherapy. Collectively, this review aims to provide a better understanding of the currently available drugs through in-depth analysis, promote the development of new therapeutic agents, and eventually improve the treatment outcomes of patients with EC.

Expression of immune checkpoint regulators, cytotoxic T lymphocyte antigen 4 (CTLA-4), and CD137 in cervical carcinoma

Immune checkpoint inhibitors have a significant role in oncology. One of these immune checkpoints is cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). Inhibition of the CTLA-4 pathway has already led to the FDA approval of Ipilimumab (anti-CTLA-4), a targeted therapy for melanoma and other malignancies. CD137 is an inducible, costimulatory receptor of the tissue-necrosis-factor-receptor superfamily expressed on the activated immune cells. Clinical trials have also been set for anti-CD137 in several malignancies. We assessed CTLA-4 and CD137 expression on a tissue microarray (TMA) comprising of 99 core tissues which included normal, non-neoplastic, and neoplastic cervical lesions. When detected as strong granular cytoplasmic reaction in the epithelial cells, CTLA-4 expression was scored as positive. For CD137, the results were recorded based on the presence or absence of staining reaction on the cell membranes of the lymphoplasmacytic infiltrates. Overall, CTLA-4 was positive in 30% (30/100) of the cervical malignancies. Sub-categorically, 20% of invasive endocervical adenocarcinomas, 63% of adenosquamous carcinomas, and 31% of squamous cell carcinomas were positive for CTLA-4 with a tendency toward lower grade squamous cell carcinomas (SCCs). CD137 was positive in 100% lymphoplasmacytic infiltrates of endocervical adenocarcinomas, 90.5% of SCCs, and 87.5% of adenosquamous carcinomas. This study has found a significant expression of CTLA-4 in cervical cancer cells and CD137 positivity of lymphoplasmacytic infiltrates with potential for future targeted immunotherapy.

Correlation between the immune checkpoints and EMT genes proposes potential prognostic and therapeutic targets in ESCC

PD-1, PD-L1, CTLA-4, TIM-3, and LAG-3, crucial immune checkpoint molecules in the tumor microenvironment, identify as key targets for cancer immunotherapy. There is a correlation between immune cells and epithelial-mesenchymal transition (EMT)-related genes expression in varies human cancers. In this study, we aimed to investigate the probable association between expression of immune checkpoints and EMT in esophageal squamous cell carcinoma (ESCC) with clinical treats for providing the new therapeutic targets and prognostic value for the disease. Quantitative real-time PCR was used to investigate the gene expression profile of immune checkpoints (PD-1, PD-L1, CTLA-4, TIM-3, and LAG-3) and EMT (TWIST1 and MMP-13) genes based on the mRNA expression levels in 51 ESCC tissues. The upregulation of CTLA-4, PD-1, PD-L1, TIM-3, LAG-3, MMP-13, and TWIST1 were observed in 31.37%, 29.41%, 21.56%, 39.21%, 25.49%, 60.78%, and 56.86% of ESCC cases at the mRNA level, respectively. Dysregulation of immune checkpoints was related to lymph node involvement, stage of tumor progression, and depth of tumor invasion (P < 0.05). While overexpression of MMP-13 and TWIST1 was associated with lymph node involvement, stage of tumor progression, and grade of tumor differentiation (P < 0.05). The mRNA expression of immune checkpoint genes was significantly correlated to each other's (P = 0.000). Of importance, the data explored the significant association between the concomitant expression of immune checkpoints and EMT-related genes with each other in a variety of clinicopathological traits (P < 0.05). Consequently, immune checkpoints were positively correlated with EMT status in ESCC. The correlation between tumor immune microenvironment with the elevation of multiple immune checkpoints and EMT status may help to identify potential biomarkers for the simultaneous clinical use of multiple immune checkpoints blockade and other immunotherapies approaches for advanced ESCC patients.

Beyond T-Cells: Functional Characterization of CTLA-4 Expression in Immune and Non-Immune Cell Types

The immune response consists of a finely-tuned program, the activation of which must be coupled with inhibitory mechanisms whenever initiated. This ensures tight control of beneficial anti-pathogen and anti-tumor responses while preserving tissue integrity, promoting tissue repair, and safeguarding against autoimmunity. A cogent example of this binary response is in the mobilization of co-stimulatory and co-inhibitory signaling in regulating the strength and type of a T-cell response. Of particular importance is the costimulatory molecule CD28 which is countered by CTLA-4. While the role of CD28 in the immune response has been thoroughly elucidated, many aspects of CTLA-4 biology remain controversial. The expression of CD28 is largely constrained to constitutive expression in T-cells and as such, teasing out its function has been somewhat simplified by a limited and specific expression profile. The expression of CTLA-4, on the other hand, while reported predominantly in T-cells, has also been described on a diverse repertoire of cells within both lymphoid and myeloid lineages as well as on the surface of tumors. Nonetheless, the function of CTLA-4 has been mostly described within the context of T-cell biology. The focus on T-cell biology may be a direct result of the high degree of amino acid sequence homology and the co-expression pattern of CD28 and CTLA-4, which initially led to the discovery of CTLA-4 as a counter receptor to CD28 (for which a T-cell-activating role had already been described). Furthermore, observations of the outsized role of CTLA-4 in T_reg-mediated immune suppression and the striking phenotype of T-cell hyperproliferation and resultant disease in CTLA-4^−/− mice contribute to an appropriate T-cell-centric focus in the study of CTLA-4. Complete elucidation of CTLA-4 biology, however, may require a more nuanced understanding of its role in a context other than that of T-cells. This makes particular sense in light of the remarkable, yet limited utility of anti-CTLA-4 antibodies in the treatment of cancers and of CTLA-4-Ig in autoimmune disorders like rheumatoid arthritis. By fully deducing the biology of CTLA-4-regulated immune homeostasis, bottlenecks that hinder the widespread applicability of CTLA-4-based immunotherapies can be resolved.

Clinical value of CTLA4 combined with clinicopathological factors in evaluating the prognosis of breast cancer

Background

Clinical prediction of breast cancer prognosis relies on both clinical-pathological features and biological markers. Many studies have revealed that tumor cytotoxic T lymphocyte antigen 4 (CTLA4) expression may present prognostic predicting value in cancers. We intended to explore the prognostic value of significant clinicopathological parameters and CTLA4 for predicting survival of patients with breast cancer.

Methods

A total of 229 breast cancer patients who had radical surgery treatment between Sep 2009 and April 2011 were enrolled in this study. Immunohistochemical staining was performed to evaluate CTLA4 grade and Ki-67 index in breast cancer tissue. Univariate and multivariate logistic analysis, Kaplan-Meier survival analysis and ROC curve were used to explore the association between CTLA4 or clinicopathological parameters and disease-free survival (DFS). A nomogram was constructed based on the regression model to predict DFS of patients with breast cancer.

Results

CTLA4 grade (OR 1.730, 95% CI: 1.213-2.468, P=0.002), Ki-67 (OR 1.449, 95% CI: 1.069-1.964, P=0.017) and N stage (lymph node metastasis) (OR 2.268, 95% CI: 1.588-3.303, P=0.000) showed significantly association with DFS of breast cancer patients. All these factors were independent predictors for poor survival, as patients with stage N2-3 tumors, high CTLA4 grade and Ki-67 index showed low survival probability (P<0.01). The conjunction of these factors exhibited good discrimination value (AUC 0.815, 95% CI: 0.749-0.882, P=0.000). Nomogram performed based on CTLA4 grade, Ki-67 index and N stage provided an efficient method to predict DFS of patients with breast cancer.

Conclusions

The high expression of CTLA4 and Ki-67 together with lymph node metastasis in breast cancer are independent risk factors that affect the prognosis of breast cancer patients. They have the potentiality to be utilized conjunctively as predictor in clinical practice.

News on immune checkpoint inhibitors as immunotherapy strategies in adult and pediatric solid tumors

Immune checkpoint inhibitors (ICIs) have shown unprecedented benefits in various adult cancers, and this success has prompted the exploration of ICI therapy even in childhood malignances. Although the use of ICIs as individual agents has achieved disappointing response rates, combinational therapies are likely to promise better results. However, only a subset of patients experienced prolonged clinical effects, thus suggesting the need to identify robust bio-markers that predict individual clinical response or resistance to ICI therapy as the main challenge. In this review, we focus on how the use of ICIs in adult cancers can be translated into pediatric malignances. We discuss the physiological mechanism of action of each IC, including PD-1, PD-L1 and CTLA-4 and the new emerging ones, LAG-3, TIM-3, TIGIT, B7-H3, BTLA and IDO-1, and evaluate their prognostic value in both adult and childhood tumors. Furthermore, we offer an overview of preclinical models and clinical trials currently under investigation to improve the effectiveness of cancer immunotherapies in these patients. Finally, we outline the main predictive factors that influence the efficacy of ICIs, in order to lay the basis for the development of a pan-cancer immunogenomic model, able to direct young patients towards more specific immunotherapy.

Prognostic impacts of tumoral expression and serum levels of PD-L1 and CTLA-4 in colorectal cancer patients

BACKGROUND

Programmed cell death ligand-1 (PD-L1) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) play a pivotal role in cancer immunotherapy. Each of these molecules has a membrane-bound receptor form (mPD-L1/mCTLA-4) and a soluble form (sPD-L1/sCTLA-4). However, these prognostic impacts in colorectal cancer (CRC) remain unclear.

METHODS

We immunohistochemically scored tumoral mPD-L1/mCTLA-4 expression and quantified preoperative circulating sPD-L1/sCTLA-4 levels using matched serum specimens from 131 patients with pStage I-III CRC. We also examined the association between these statuses and tumor infiltrating lymphocytes (TILs) in these patients.

RESULTS

Elevated levels of mPD-L1, mCTLA-4, sPD-L1 and sCTLA-4 were significantly correlated with poor overall survival (OS) and disease-free survival (DFS). Co-high expression of tumoral mPD-L1 and mCTLA-4 or co-elevated levels of serum sPD-L1 and sCTLA-4 were strongly correlated with poor OS and DFS. Multivariate analysis revealed that both statuses were negative independent prognostic factors for OS [hazard ratio (HR) 3.86, 95% confidence interval (95% CI) 1.71-8.51, p = 0.001; HR 5.72, 95% CI 1.87-14.54, p = 0.004, respectively] and DFS (HR 2.53, 95% CI 1.23-4.95, p = 0.01; HR 6.88, 95% CI 2.42-17.13, p = 0.0008, respectively). Although low expression of tumoral mCTLA-4 was significantly correlated with increased CD8(+) TILs, there was no correlation in any other combination.

CONCLUSIONS

We verified the prognostic impacts of mPD-L1, mCTLA-4, sPD-L1 and sCTLA-4 in pStage I-III CRC patients. Dual evaluation of immune checkpoint molecules in primary tissues or preoperative serum could identify a patient population with poor prognosis in these patients.

Clinical Relevance of the serum CTLA-4 in Cats with Mammary Carcinoma

Cytotoxic T lymphocyte associated antigen 4 (CTLA-4) serves an important role in breast cancer progression, which has led to the development of novel immunotherapies aimed at blocking tumor immune evasion. Although feline mammary carcinoma is increasingly recognized as a valuable cancer model, no studies on CTLA-4 function had been conducted in this species. The serum CTLA-4, TNF-α and IL-6 levels of 57 female cats with mammary carcinoma were determined by ELISA, and immunohistochemistry was performed to evaluate CTLA-4 and FoxP3 expression in tumor cells and interstitial lymphocytes. The results obtained show that serum CTLA-4 levels are increased in cats with mammary carcinoma (P = 0.022), showing an association with a number of clinicopathological features: smaller tumor size, P < 0.001; absence of tumor necrosis, P < 0.001; non-basal status, P < 0.02 and HER-2-positive status. Additionally, a strong positive correlation was found between serum CTLA-4 levels and serum TNF-α (R = 0.88, P < 0.001) and IL-6 levels (R = 0.72, P < 0.001). Concerning the CTLA-4 and FoxP3 expression, although detected in both interstitial lymphocytes and tumor cells, a positive association was found only between interstitial CTLA-4 and FoxP3 expressions (R = 0.387, P = 0.01), which is negatively associated with the serum CTLA-4 levels (P = 0.03). These findings provide a preliminary step in the characterization of immune profiles in feline mammary carcinoma, uncovering a molecular rationale for targeted therapy with CTLA-4 pathway inhibitors. Finally, by strengthening the hypothesis of an immunomodulatory role for this regulator, we further validate the utility of spontaneous feline mammary carcinoma as a model for human breast cancer.

Anti-inflammatory microenvironment of esophageal adenocarcinomas negatively impacts survival

Objective

Reflux promotes esophageal adenocarcinomas (EACs) creating a chronic inflammatory environment. Survival rates are low due to early local recurrences and distant metastasis. Hence, there is a need for new potential treatment options like immunotherapies. However, the inflammatory microenvironment in EACs and its impact on patient outcome remain to be fully understood.

Methods

mRNA expression levels of pro- and anti-inflammatory markers in 39 EAC patients without neoadjuvant radio-chemotherapy were measured. Data were confirmed using flow cytometric analysis of freshly resected surgical specimens. Inflammatory alterations in premalignant lesions of Barrett’s esophagus were analyzed by immunohistochemistry.

Results

Expression levels of IL22 were reduced in EAC, while expression levels of FOXP3, IL10 and CTLA4 were increased. Flow cytometry demonstrated a strong infiltration of CD4⁺ T cells with a reduction in CD4⁺ T cells producing IL-22 or IL-17A. We also observed an increase in CD4⁺CD127^lowFOXP3⁺ cells producing IL-10. Accumulation of FOXP3⁺ T cells occurred prior to malignant changes. High expression of IL10 and low expression of IL22 in EAC were associated with reduced overall survival. Moreover, increased expression of IL10, CTLA4 and PD1 in the unaltered esophageal mucosa distant to the EAC was also linked with an unfavorable prognosis.

Conclusion

EAC shows an anti-inflammatory environment, which strongly affects patient survival. The microscopically unaltered peritumoral tissue shows a similar anti-inflammatory pattern indicating an immunological field effect, which might contribute to early local recurrences despite radical resection. These data suggest that using checkpoint inhibitors targeting anti-inflammatory T cells would be a promising therapeutic strategy in EAC.

Electronic supplementary material

The online version of this article (10.1007/s00262-020-02517-8) contains supplementary material, which is available to authorized users.

Association of cytotoxic T-lymphocyte associated protein 4 gene polymorphisms with the risk and prognosis of oesophageal cancer in a high-incidence region from northern China

The most important anti-tumour immune response is mediated by T lymphocytes. Cytotoxic T lymphocyte-associated protein 4 (CTLA4) plays a critical role in the immune surveillance against tumours as an inhibitory immune checkpoint molecule of T-cell activation. This study was designed to explore the association of CTLA4 polymorphisms with the susceptibility to oesophageal squamous cell carcinoma (ESCC) and prognosis of patients with ESCC in a high-incidence population from northern China. CTLA4 rs5742909 C/T and rs231775 G/A single nucleotide polymorphisms (SNPs) were genotyped using polymerase chain reaction-ligase detection reaction (PCR-LDR) method in 577 ESCC patients and 580 controls. Upper gastrointestinal cancer family history increased the risk of ESCC (the sex-, age- and smoking status-adjusted OR = 1.383, 95%CI = 1.094-1.749). The genotype frequencies of these two SNPs in the patients with ESCC were similar to that in the controls. Survival analyses were conducted in 204 patients with ESCC with five-year survival information. The mean survival time of ESCC patients with rs231775 SNP A/A genotype in age over 60 years group was 23.2 months, significantly shorter than that of those with G/G genotype (47.3 months). The A/A genotype was associated with increased death risk of patients with ESCC older than 60 years (adjusted HR = 4.544, 95%CI = 1.913-10.790). CTLA4 rs231775 SNP might be used as genetic marker of worse prognosis for patients with ESCC over 60 years in a high-incidence population from northern China.

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.

The Common Costimulatory and Coinhibitory Signaling Molecules in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinomas (HNSCCs) are closely linked with immunosuppression, accompanied by complex immune cell functional activities. The abnormal competition between costimulatory and coinhibitory signal molecules plays an important role in the malignant progression of HNSCC. This review will summarize the features of costimulatory molecules (including CD137, OX40 as well as CD40) and coinhibitory molecules (including CTLA-4, PD-1, LAG3, and TIM3), analyze the underlying mechanism behind these molecules' regulation of the progression of HNSCC, and introduce the clinic application. Vaccines, such as those targeting STING while working synergistically with monoclonal antibodies, are also discussed. A deep understanding of the tumor immune landscape will help find new and improved tumor immunotherapy for HNSCC.

Immune inhibitory function of bovine CTLA-4 and the effects of its blockade in IFN-γ production

BACKGROUND

Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is known as an immune inhibitory receptor that is expressed on activated effector T cells and regulatory T cells. When CTLA-4 binds to CD80 or CD86, immunoinhibitory signals are transmitted to retain a homeostasis of the immune response. Recent studies have reported that CTLA-4 is upregulated in chronic infections and malignant neoplasms, contributing to host immune dysfunction. On the other hand, the blockade of CTLA-4 and CD80 or CD86 binding by antibody restores the immune response against these diseases. In a previous report, we indicated that the expression of CTLA-4 was closely associated with disease progression in cattle infected with the bovine leukemia virus (BLV). In this study, we established an anti-bovine CTLA-4 antibody to confirm its immune enhancing effect.

RESULTS

Bovine CTLA-4-Ig binds to bovine CD80 and CD86 expressing cells. Additionally, CD80 and CD86 bind to CTLA-4 expressing cells in an expression-dependent manner. Bovine CTLA-4-Ig significantly inhibited interferon-gamma (IFN-γ) production from bovine peripheral blood mononuclear cells (PBMCs) activated by Staphylococcus enterotoxin B (SEB). An established specific monoclonal antibody (mAb) for bovine CTLA-4 specifically recognized only with bovine CTLA-4, not CD28, and the antibody blocked the binding of CTLA-4-Ig to both CD80 and CD86 in a dose-dependent manner. The bovine CTLA-4 mAb significantly restored the inhibited IFN-γ production from the CTLA-4-Ig treated PBMCs. In addition, the CTLA-4 mAb significantly enhanced IFN-γ production from CTLA-4 expressing PBMCs activated by SEB. Finally, we examined whether a CTLA-4 blockade by CTLA-4 mAb could restore the immune reaction during chronic infection; the blockade assay was performed using PBMCs from BLV-infected cattle. The CTLA-4 blockade enhanced IFN-γ production from the PBMCs in response to BLV-antigens.

CONCLUSIONS

Collectively, these results suggest that anti-bovine CTLA-4 antibody can reactivate lymphocyte functions and could be applied for a new therapy against refractory chronic diseases. Further investigation is required for future clinical applications.

Immune checkpoint inhibitors: a new era for esophageal cancer

Introduction: The poor prognosis for patients with esophageal cancer (EC) requires evolving current treatment regimens. Immune checkpoint inhibitors show clinical efficacy and a great safety profile in multiple tumors. And the monoclonal antibodies that target programmed death receptor-1/programmed death receptor ligand-1 or the cytotoxic T lymphocyte antigen-4 pathway has shown potential curable effect of EC. Areas covered: This review article covers the prognostic significance of immune checkpoint expression, the accumulating current clinical studies of checkpoint inhibitors in esophageal cancer patients, and future directions. Expert opinion: Many clinical studies have reported favorable survival results with manageable toxicity of anti-programmed death receptor-1/programmed death receptor ligand-1 and anti-cytotoxic T lymphocyte antigen-4 treatment. More results are expected from future clinical studies. It is believed that combining chemoradiotherapy and immune checkpoint inhibitors can induce safe and efficient anti-tumor immune responses and can be a promising therapeutic strategy.

Prognostic Value of Combined Analysis of CTLA-4 and PLR in Esophageal Squamous Cell Carcinoma (ESCC) Patients

Objective

The purpose of this study was to evaluate the prognostic role of the cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) expression level and the platelet lymphocyte ratio (PLR) level in esophageal squamous cell carcinoma (ESCC) patients.

Methods

84 ESCC patients who received surgical treatment in our hospital were enrolled in the study. The correlation of each biomarker's level with ESCC patients' clinicopathological characteristics and overall survival (OS) was assessed.

Results

The elevated expression rate of T-CTLA-4 (tumor cell CTLA-4) and I-CTLA-4 (interstitial lymphocyte CTLA-4) was 48.8% and 44.0%, respectively. The number of enrolled patients with a higher PLR level (≥119) was 48. The prognostic value of T-CTLA-4, I-CTLA-4, and PLR in ESCC patients was not detected. However, patients with both a low T-CTLA-4 expression level and a low PLR level that had longer OS (p = 0.023) were found. The prognostic role of T-CTLA-4(-) +PLR (-) status in ESCC patients was also confirmed in multivariate analyses (p = 0.027).

Conclusion

These results demonstrated the potential prognostic value of combined analysis of CTLA-4 and PLR in ESCC patients.

A good start of immunotherapy in esophageal cancer

Considering the benefits of immunotherapy in advanced melanoma, non–small cell lung cancer, renal cell carcinoma, bladder cancers, and refractory Hodgkin lymphoma, we begin to consider whether immunotherapy is effective for esophageal cancer, which is extremely malignant and has a poor prognosis. There are a large number of clinical trials to study the application of immunotherapy such as immune checkpoint inhibitors, peptide vaccine, adoptive T cell transfer and oncolytic virus in esophageal cancer. Some already have preliminary results and show the advantages of immunotherapy in esophageal cancer, while others are still in progress. This review aims to introduce the feasibility and current status of immunotherapy in esophageal cancer.

Leukemic B Cell CTLA-4 Suppresses Costimulation of T Cells

The clinical benefit of CTLA-4 blockade on T cells is known, yet the impact of its expression on cancer cells remains unaddressed. We define an immunosuppressive role for tumor-expressed CTLA-4 using chronic lymphocytic leukemia (CLL) as a disease model. CLL cells, among other cancer cells, are CTLA-4⁺ Coculture with activated human T cells induced surface CTLA-4 on primary human CLL B cells. CTLA-4 on CLL-derived human cell lines decreased CD80 expression on cocultured CD80⁺ cells, with restoration upon CTLA-4 blockade. Coculture of CTLA-4⁺ CLL cells with CD80-GFP⁺ cell lines revealed transfer of CD80-GFP into CLL tumor cells, similar to CTLA-4⁺ T cells able to trans-endocytose CD80. Coculture of T cells with CTLA-4⁺ CLL cells decreased IL-2 production. Using a human CTLA-4 knock-in mouse lacking FcγR function, antitumor efficacy was observed by blocking murine CTLA-4 on tumor cells in isolation of the T cell effect and Fc-mediated depletion. These data implicate tumor CTLA-4 in cancer cell-mediated immunosuppression in vitro and as having a functional role in tumor cells in vivo.

Potential function of CTLA-4 in the tumourigenic capacity of melanoma stem cells

Extensive clinical evidence supports that cytotoxic T lymphocyte antigen-4 (CTLA-4) is expressed in a variety of human malignant tumour cells in addition to T cells. In certain types of cancer, the overexpression of CTLA-4 is associated with poor patient prognosis. However, few studies have demonstrated the effects of tumour-intrinsic CTLA-4 in cancer stem cells, including melanoma stem cells (MSCs). In the present study, it was demonstrated that melanoma cell-intrinsic CTLA-4 induced tumour cell proliferation in vitro and suppressed tumour cell apoptosis. Furthermore, CTLA-4 was expressed in aldehyde dehydrogenase (ALDH)+ MSCs. CTLA-4 inhibited MSCs proliferation in vitro by blocking antibodies and significantly downregulated ALDH1A1, ALDH1A3 and ALDH2 mRNA expression (P<0.01). Functionally, blocking CTLA-4 in melanoma cell lines suppressed the properties of stem-like cells, including ALDH activity and significantly suppressed the ability of these cells to form spheres in vitro (P<0.05). In addition, the blocking of CTLA-4 in melanoma cells suppressed the properties of stem-like cells in vivo, including the capacity for tumourigenesis. The presence of residual ALDH+ MSCs within the tumour was observed, and the blocking CTLA-4 significantly decreased the number of residual ALDH+ MSCs in vivo (P<0.01). Altogether, these results indicate the identification of a novel mechanism underlying melanoma progression in the present study and that CTLA-4-targeted therapy may benefit candidate CTLA-4-targeted therapy by improving the long-term outcome for patients with advanced stages of melanoma.

A meta-analysis of transcriptome datasets characterizes malignant transformation from melanocytes and nevi to melanoma

Melanoma represents one of the most aggressive malignancies and has a high tendency to metastasize. The present study aims to investigate the molecular mechanisms of two pathways to cancer transformation with the purpose of identifying potential biomarkers. Our approach is based on a meta-analysis of gene expression profiling contrasting two scenarios: A model that describes a transformation pathway from melanocyte to melanoma and a second model where transformation occurs through an intermediary nevus. Data consists of three independent, publicly available microarray datasets from the Gene Expression Omnibus (GEO) database comprising samples from melanocytes, nevi and melanoma. The present analysis identified 808 differentially expressed genes (528 upregulated and 360 downregulated) in melanoma compared with nevi, and 2,331 differentially expressed genes (946 upregulated and 1,385 downregulated) in melanoma compared with melanocytes. Further analysis narrowed down this list, since 682 differentially expressed genes were found in both models (417 upregulated and 265 downregulated). Enrichment analysis identified relevant dysregulated pathways. This article also presented a discussion on significant genes including ADAM like decysin 1, neudesin neurotrophic factor, MMP19, apolipoprotein L6, C-X-C motif chemokine ligand (CXCL)8, basic, immunoglobulin-like variable motif containing and CXCL16. These are of particular interest because they encode secreted proteins hence represent potential blood biomarkers for the early detection of malignant transformation in both scenarios. Cytotoxic T-lymphocyte associated protein 4, an important therapeutic target in melanoma treatment, was also upregulated in both comparisons indicating a potential involvement in immune tolerance, not only at advanced stages but also during the early transformation to melanoma. The results of the present study may provide a research direction for studying the mechanisms underlying the development of melanoma, depending on its origin.

Expression of immune checkpoint regulators, cytotoxic T lymphocyte antigen 4 (CTLA-4) and programmed death-ligand 1 (PD-L1), in female breast carcinomas

BACKGROUND

Immune checkpoint regulators, cytotoxic T lymphocyte antigen 4 (CTLA-4) and the programmed cell death protein-1/programmed death-ligand 1 (PD-1/PD-L1) have emerged as promising new targets for cancer therapeutics. While tumor expression of PD-L1 has been shown to have objective responses to anti-PD-L1 immunotherapies, the clinical implications of CTLA-4 expression in tumor cells or immune cells in the tumor microenvironment is still controversial. We investigated the expression of CTLA-4 and PD-L1 in human breast tumors and provided a scoring system for the systematic evaluation of CTLA-4 staining.

METHODS

Immunohistochemical staining for PD-L1 and CTLA-4 expression was performed on a tissue microarray of 102 cores, which included normal and neoplastic breast tissues. Neoplastic cores were divided into four groups: Ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC), invasive lobular carcinoma (ILC) and invasive tubular carcinoma (ITC). PD-L1 and CTLA-4 expressions were scored based on a system which accounted for the percentage and intensity of positivity and results provided in conjunction with available clinical and demographic data.

RESULTS

Overall, CTLA-4 was over-expressed in 49 of 93 (52.7%) breast tumors. Subcategorically, CTLA-4 was positive in 3 of 8 (37.5%) ductal carcinoma in situ, 40 of 73 (55%) of invasive ductal carcinomas, 4 of 10 (40%) of invasive lobular carcinomas and 2 of 2 (100%) of invasive tubular carcinomas. All 6 normal breast tissues were interpreted as negative for CTLA-4 staining. Only 4.1% of the invasive ductal carcinomas were positive for PD-L1 reactivity and the remaining carcinomas stained negative.

CONCLUSIONS

This study shows a significant overexpression of CTLA-4 in >50% of breast carcinomas with no such overexpression of CTLA-4 in benign breast tissues. PDL-1 staining is seen in only a small number of invasive ductal carcinomas (4.1%). These findings suggest the need for further investigation of anti-CTLA-4 and anti-PD-L1 immunotherapies and their efficacy in the treatment of breast carcinomas with overexpression of these immune modulators. In addition, the proposed scoring system will facilitate a more systematic correlation between tumor reactivity and clinical outcome which can be applied to all intracytoplasmic tumor markers.

Albumin/globulin ratio is negatively correlated with PD-1 and CD25 mRNA levels in breast cancer patients

Background

Previous studies have demonstrated the prognostic value of globulin (GLB), albumin (ALB), the ALB/GLB ratio (AGR), body mass index (BMI), hemoglobin (Hb), and prognostic nutritional index (PNI) in breast cancer. The underlying mechanism has been investigated by examining the impact of nutritional parameters on T cells, natural killer cells, and dendritic cells, but little is known about their effect on checkpoint molecules.

Methods

Here, we investigated the correlation of mRNA expression of programmed cell death protein 1 (PD-1), cluster of differentiation 28 (CD28), cytotoxic T-lymphocyte antigen-4 (CTLA-4), and cluster of differentiation 25 (CD25) with AGR, ALB, GLB, total protein, pre-ALB, Hb, BMI, and PNI in the peripheral blood of breast cancer patients. One hundred and three patients and 21 age- and sex-matched healthy controls were enrolled. Quantitative real-time PCR was used to test relative mRNA expression.

Results

The results indicated that the mRNA levels of PD-1 and CD25 were 5.2- and 3.3-fold higher in patients with low AGR than in those with high AGR (P < 0.05). The mRNA levels of PD-1 were 3.5-fold higher in patients with high GLB than in those with low GLB (P < 0.05). In addition, breast cancer patients had higher expression levels of PD-1, CD28, CTLA-4, and CD25 mRNA in their peripheral blood compared with healthy volunteers (P < 0.05).

Conclusion

These results suggest that AGR is negatively correlated with PD-1 and CD25 mRNA levels, while GLB is positively associated with PD-1 mRNA levels. Nutritional status in breast cancer patients may influence the PD-1 pathway and have implications for the optimization of cancer therapy.

High CTLA-4 expression correlates with poor prognosis in thymoma patients

Thymomas, tumors that arise from epithelial cells of the thymus gland, are the most common neoplasms of the anterior mediastinum, with an incidence rate of approximately 2.5 per million/year. Cytotoxic T Lymphocyte Antigen 4 (CTLA-4 or CD152) exerts inhibitory activity on T cells, and since its oncogenic role in the progression of different types of tumors, it has emerged as a potential therapeutic target in cancer patients.

In this study, we assessed the expression of CTLA-4 both at mRNA and protein levels in paraffin embedded-tissues from patients with thymomas. Furthermore, we evaluated the relationship between CTLA-4 expression and the clinical-pathologic characteristics and prognosis in patients with thymomas. Sixty-eight patients with median age corresponding to 62 years were included in this analysis. Thymomas were classified accordingly to the WHO and Masaoka-Koga for histochemical analysis and for prognostic significance.

A statistical difference was found between CTLA-4 mRNA levels in human normal thymus compared with thymoma specimens. CTLA-4 expression was statistically found to progressively increase in A, B1, B2, AB and it was maximal in B3 thymomas. According to Masaoka-Koga pathological classification, CTLA-4 expression was lower in I, IIA and IIB, and higher in invasive III and IV stages. By confocal microscopy analysis we identified the expression of CTLA-4 both in tumor cells and in CD45⁺ tumor-infiltrating leukocytes, mainly in B3 and AB thymomas.

Finally, CTLA-4 overexpression significantly correlates with reduced overall survival in thymoma patients and in atypical thymoma subgroup, suggesting that it represents a negative prognostic factor.

High cytotoxic T-lymphocyte-associated antigen 4 and phospho-Akt expression in tumor samples predicts poor clinical outcomes in ipilimumab-treated melanoma patients

Ipilimumab, a fully human monoclonal antibody against cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), is the first immune checkpoint inhibitor approved for the treatment of unresectable melanoma on the basis of its overall survival (OS) benefit. However, ipilimumab is associated with significant immune-related adverse events. We hypothesized that biomarker exploration of pretreatment tumor samples and correlation with clinical outcome would enable patient selection with an increased benefit/risk ratio for ipilimumab therapy. At the University of Texas MD Anderson Cancer Center, a total of 81 advanced melanoma patients were treated on the Ipilimumab Expanded Access Program from 2007 to 2008. Using immunohistochemistry, we analyzed the expression of immune checkpoint (CTLA-4, PD-1, PD-L1) and Akt-pathway proteins in formalin-fixed tumor tissue. Associations between these biomarkers and progression-free survival (PFS) and OS were analyzed with univariate and multivariate Cox proportional-hazards models. There was a significant correlation between high CTLA-4 protein expression levels in tumor cells and risk of death (P=0.02) and decreased PFS (P=0.023). In addition, high expression of CTLA-4 in peritumoral lymphocytes correlated with poor OS (P=0.023). In multivariate analysis, patients with high CTLA-4 and phospho-Akt (p-Akt) expression correlated with poor OS (log-rank test, P=0.039) and PFS (log-rank test, P=0.014). High levels of CTLA-4 and p-Akt expression in pretreatment tumor cells in melanoma patients were associated with poor clinical outcomes. Immunohistochemistry analysis of CTLA-4 and p-Akt in pretreatment tumor samples provides useful biomarkers that may enable improved patient selection for ipilimumab therapy. Prospective clinical studies are warranted to investigate the predictive value of these biomarkers.

Cytotoxic T lymphocyte associated antigen 4 expression predicts poor prognosis in luminal B HER2-negative breast cancer

Cytotoxic T lymphocyte associated antigen 4 (CTLA-4) serves an important role in inhibiting anti-tumor immune response in the majority of solid tumors. However, a limited number of studies reported the function of CTLA-4 in luminal B HER2-negative breast cancer. Immunohistochemistry was performed to evaluate the expression of tumor and interstitial CTLA-4 in luminal B HER2-negative breast cancer tissues. The percentage of patients with tumor and interstitial CTLA-4⁺ was 41.2% (42/102) and 46.1% (47/102), respectively. There was a positive association between tumor CTLA-4 expression and interstitial CTLA-4 expression (P<0.05). The disease-free survival (DFS) of the tumor CTLA-4⁺ group was significantly shorter compared with patients with tumor CTLA-4^- (mean, 89.070 vs. 39.022 months; P<0.0001). Additionally, the DFS of interstitial CTLA-4⁺ group was shorter compared with the interstitial CTLA-4^- group (mean, 85.526 vs. 46.574 months; P<0.0001). Tumor and interstitial CTLA-4 expression may have prognostic predicting value in luminal B HER2-negative breast cancer. The present study may provide the basis for the use of a CTLA-4 blocker in patients with luminal B HER2-negative breast cancer.

Advances in T-cell checkpoint immunotherapy for head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) has been found to be a complex group of malignancies characterized by their profound immunosuppression and high aggressiveness. In most cases of advanced HNSCC, treatment fails to obtain total cancer cure. Efforts are needed to develop new therapeutic approaches to improve HNSCC outcomes. In this light, T-cells "immune checkpoint" has attracted much attention in cancer immunotherapy. It has been broadly accepted that inhibitory T-cell immune checkpoints contribute to tumor immune escape through negative immune regulatory signals (cytotoxic T-lymphocyte-associated antigen 4 [CTLA-4], programmed cell death 1 [PD-1], B7-H3, and B7-H4, etc). Current data suggest that PD-1 and CTLA-4 receptors can inhibit T-cell receptors and T-cell proliferation. Blockade of PD-1/PD-L1 and/or CTLA-4/CD28 pathways has shown promising tumor outcomes in clinical trials for advanced solid tumors like melanoma, renal cell cancer, and non-small cell lung cancer. The present review attempts to explore what is known about PD-1/PD-L1 and CTLA-4/CD28 pathways with a focus on HNSCC. We further discuss how these pathways can be manipulated with therapeutic intent.

CTLA-4 expression in the non-small cell lung cancer patient tumor microenvironment: diverging prognostic impact in primary tumors and lymph node metastases

The immune checkpoint receptor CTLA-4 plays a crucial part in negatively regulating T cell activation and maintaining self-tolerance. It is frequently overexpressed in a variety of malignancies, yet its prognostic impact in non-small cell lung cancer (NSCLC) remains unclear. We constructed tissue microarrays from tumor tissue samples and evaluated the immunohistochemical expression of CTLA-4 in 536 patients with primary resected stage I-IIIA NSCLC. Expression of CTLA-4 was analyzed in tumor and stromal primary tumor tissue and in locoregional metastatic lymph nodes. CTLA-4 expression in neither tumor epithelial cells (T-CTLA-4) nor stromal cells (S-CTLA-4) of primary tumors was significantly associated with disease-specific survival (DSS) in all patients. However, high S-CTLA-4 expression independently predicted significantly improved DSS in the squamous cell carcinoma subgroup (HR 0.62, 95% CI 0.41-0.93, P = 0.021). In contrast, there was an independent negative prognostic impact of T-CTLA-4 expression in metastatic lymph nodes (HR 1.65, 95% CI 1.03-2.65, P = 0.039). Our results indicate that the expression of CTLA-4 has diverging prognostic impacts in metastatic NSCLC lymph nodes versus primary tumors. The presented results highlight important differences in the tumor microenvironments of primary and metastatic NSCLC tissues, and have potential to guide treatment and clinical sampling strategies.

Targeting Immune Checkpoints in Esophageal Cancer: A High Mutational Load Tumor

Checkpoint inhibitors (eg, programmed cell death protein 1 [PD-1], programmed cell death ligand 1 [PD-L1], cytotoxic T-lymphocyte associated protein 4 [CTLA-4] antibodies) are changing how we understand cancer and provide a means to develop modern immunotherapies. An emergent notion relates success with checkpoint inhibitors with high mutational load tumors. There are few studies that examine checkpoint protein expression and relate these to clinical outcomes after the conventional treatment of patients with esophageal cancer, which has a high mutational load. The objective of this review is to summarize the literature that examines checkpoint expression and clinical outcomes, as well as propose an accelerated approach to introducing these therapies into the clinic to treat patients with esophageal cancer.

The prognostic value of cytotoxic T-lymphocyte antigen 4 in cancers: a systematic review and meta-analysis

The outcomes of studies analyzing the prognostic role of CTLA-4 in cancers are controversial. Therefore, the aim of our meta-analysis was to clarify the correlation between CTLA-4 expression and OS in different cancer cases. Relevant literature was searched using PubMed, EMBASE, Web of Science, and the Cochrane Library. The clinicopathological features, hazard ratio (HR) and 95% confidence intervals (CI) were collected from these studies and were analyzed using Stata version 12.0 software. The pooled HR values showed no significant correlation between CTLA-4 expression levels and OS in relation to tumors (HR: 1.24, 95% CI: 0.98–1.56, I2 = 71.7%, P = 0.000). Further subgroup analyses were conducted and categorized by experimental methods, CTLA-4 sources and cancer types. The survey showed a significant correlation (HR: 1.47, 95% CI: 1.14–1.89) between high expression of CTLA-4 and OS in the SNP subgroup, and subgroups analyzing by PCR (HR: 1.50, 95% CI: 1.20–1.86) and flow cytometry (HR: 2.76, 95% CI: 1.49–5.14). In addition, our analysis observed significant differences between patients and controls in inCTLA-4+CD4+ lymphocytes, surCTLA-4+CD4+ lymphocytes, inCTLA-4+CD8+ lymphocytes, and surCTLA-4+CD8+ lymphocytes. Knowledge of the effects of CTLA-4 could potentially be used to effectively guide appropriate prognosis and therapeutic strategies in cancer patients.

Analysis of the prognostic role of an immune checkpoint score in resected non-small cell lung cancer patients

Tumors develop mechanisms to recruit tolerogenic immune cells and to induce the expression of molecules that act as immune checkpoints. This regulation of the immune microenvironment favors immune tolerance to the neoplastic cells. In this study, we have investigated the prognostic role of immune-checkpoint expression markers in a cohort of resectable non-small cell lung cancer (NSCLC) patients. RNA was isolated from fresh-frozen lung specimens (tumor and normal lung) (n = 178). RTqPCR was performed to analyze the relative expression of 20 immune-related genes that were normalized by the use of endogenous genes selected by GeNorm algorithm. Patients with higher expression levels of IL23A and LGALS2 presented better outcomes. In the clustering expression patterns, we observed that patients with higher expression of immunoregulatory genes had better survival rates. Additionally, these data were used to develop a gene expression score. Since CTLA4 and PD1 were associated with prognosis based on Cox regression analysis (Z-score > 1.5), a multivariate model including these two genes was created. Absolute regression coefficients from this analysis were used in order to calculate the immune-checkpoint score: (PD1×0.116) + (CTLA4×0.059) for each case. Kaplan-Meier survival analysis showed that patients with high immune-checkpoint score have longer overall survival (OS) [NR vs. 40.4 mo, p = 0.008] and longer relapse-free survival (RFS) [82.6 vs. 23 mo, p = 0.009]. Multivariate analysis in the entire cohort indicated that the immune-checkpoint score was an independent biomarker of prognosis for OS [HR: 0.308; 95% CI, 0.156-0.609; p = 0.001] and RFS [HR: 0.527; 95% CI, 0.298-0.933; p = 0.028] in early-stage NSCLC patients. In conclusion, this score provides relevant prognostic information for a better characterization of early stage NSCLS patients with strikingly different outcomes and who may be candidates for immune-based therapies.