Upregulation of circulating PD-L1/PD-1 is associated with poor post-cryoablation prognosis in patients with HBV-related hepatocellular carcinoma

Combined cryoablation and PD-1 inhibitor synergistically enhance antitumor immune responses in Lewis lung adenocarcinoma mice via the PI3K/AKT/mTOR pathway

Cryoablation is a therapeutic modality for lung adenocarcinoma that destroys target tumors using lethal levels of cold, resulting in the release of large amounts of specific antigens that activate immune responses. However, tumor immune checkpoint escape mechanisms prevent these released self-antigens from inducing effective anti-tumor immune responses. To overcome this challenge, we propose the use of immune checkpoint inhibitors to relieve T cell inhibition by immune checkpoints and enhance the anti-tumor immune response mediated by cryoablation. We used bilateral tumor-bearing mouse models and a specific cryoablation instrument to study the efficacy of cryoablation combined with PD-1 inhibitors in Lewis lung adenocarcinoma model mice. We found that cryoablation combined with PD-1 inhibitors significantly inhibited the growth of mouse lung adenocarcinoma, prolonged mouse survival, and enhanced the anti-tumor immune response. Moreover, this combined regimen could synergistically promote the activation and proliferation of T cells via the PI3K/AKT/mTOR pathway. The present study provides a strong theoretical basis for the clinical combination of cryoablation and PD-1 inhibitors.

Treatment Options for Hepatocellular Carcinoma Using Immunotherapy: Present and Future

Hepatocellular carcinoma (HCC) is a common cancer, and the body's immune responses greatly affect its progression and the prognosis of patients. Immunological suppression and the maintenance of self-tolerance in the tumor microenvironment are essential responses, and these form part of the theoretical foundations of immunotherapy. In this review, we first discuss the tumor microenvironment of HCC, describe immunosuppression in HCC, and review the major biomarkers used to track HCC progression and response to treatment. We then examine antibody-based therapies, with a focus on immune checkpoint inhibitors (ICIs), monoclonal antibodies that target key proteins in the immune response (programmed cell death protein 1, anti-cytotoxic T-lymphocyte associated protein 4, and programmed death-ligand 1) which have transformed the treatment of HCC and other cancers. ICIs may be used alone or in conjunction with various targeted therapies for patients with advanced HCC who are receiving first-line treatments or subsequent treatments. We also discuss the use of different cellular immunotherapies, including T cell receptor (TCR) T cell therapy and chimeric antigen receptor (CAR) T cell therapy. We then review the use of HCC vaccines, adjuvant immunotherapy, and oncolytic virotherapy, and describe the goals of future research in the development of treatments for HCC.

The Therapeutic Potential of Cytokine-Induced Killer in Patients with Cancer

Despite the promising results of immunotherapy, further experiments need to be considered because of several factors ranging from physical barriers to off-tumor adverse effects. It is surprising that adoptive cellular immunotherapy, particularly dendritic cell and cytokine-induced killer (DC-CIK) therapy, is far less emphasized in the treatment of cancer diseases. DC-CIK therapy in cancer patients presents auspicious results with low or no side effects, which should not be overlooked. More interestingly, almost all DC-CIK clinical trials are ongoing in China that highlight the limitations of therapeutic strategies and require large-scale research. To date, it is advisable to consider combination therapy with chemotherapy since it has shown promising outcomes with higher efficacy. In this article, the efficacy of DC-CIK therapy in patients with cancer is summarized by underscoring the lack of experiments on soft cancers on an unprecedented scale. In brief, DC-CIK therapy is a safe and effective therapeutic agent for malignant and nonmalignant diseases that enhances short-term and long-term effects.

The immune response of hepatocellular carcinoma after locoregional and systemic therapies: The available combination option for immunotherapy

Hepatocellular carcinoma (HCC) is associated with a highly heterogeneous immune environment that produces an immune response to various locoregional treatments (LRTs), which in turn affects the effectiveness of immunotherapy. Although LRTs still dominate HCC therapies, 50-60% of patients will ultimately be treated with systemic therapies and might receive those treatments for the rest of their life. TACE, SIRT, and thermal ablation can dramatically increase the immunosuppressive state of HCC, a condition that can be addressed by combination with immunotherapy to restore the activity of lymphocytes and the secretion of cellular immune factors. Immune treatment with locoregional and systemic treatments has dramatically changed the management of HCC. In this review, we examine the research on the changes in the immune microenvironment after locoregional or systemic treatment. We also summarize the regulation of various immune cells and immune factors in the tumor microenvironment and discuss the different infiltration degrees of immune cells and factors on the prognosis of HCC to better compare the efficacy between different treatment methods from the perspective of the tumor microenvironment. This information can be used to help develop treatment options for the upcoming new era of HCC treatment in the future.

The programed death-1/programed death ligand-1 axis and its potential as a therapeutic target for virus-associated tumours

As an important and serious condition impacting human health, the diagnosis, and treatment of tumours is clinically vital because tumour cell immune escape sustains tumour development. Programed death ligand-1 (PD-L1) on tumour cell surfaces binds to the programed death-1 (PD-1), inhibits T cell activation, and induces apoptosis, and incapacitates cells. This allows tumour cells to evade recognition and clearance by the immune system, thereby permitting tumour occurrence, and development and poor prognosis outcomes in patients with tumours. Currently, anti-PD-1/PD-L1 immunotherapy has become pivotal in tumour treatment. Pathogens, especially viruses, are important factors which induce many tumours. In this article, we examine associations between Epstein-Barr virus, human papilloma virus, hepatitis B virus, hepatitis C virus, and human immunodeficiency virus type 1-related tumours and PD-1/PD-L1 axis.

The current status and future of PD-L1 in liver cancer

The application of immunotherapy in tumor, especially immune checkpoint inhibitors (ICIs), has played an important role in the treatment of advanced unresectable liver cancer. However, the efficacy of ICIs varies greatly among different patients, which has aroused people's attention to the regulatory mechanism of programmed death ligand-1 (PD-L1) in the immune escape of liver cancer. PD-L1 is regulated by multiple levels and signaling pathways in hepatocellular carcinoma (HCC), including gene variation, epigenetic inheritance, transcriptional regulation, post-transcriptional regulation, and post-translational modification. More studies have also found that the high expression of PD-L1 may be the main factor affecting the immunotherapy of liver cancer. However, what is the difference of PD-L1 expressed by different types of cells in the microenvironment of HCC, and which type of cells expressed PD-L1 determines the effect of tumor immunotherapy remains unclear. Therefore, clarifying the regulatory mechanism of PD-L1 in liver cancer can provide more basis for liver cancer immunotherapy and combined immune treatment strategy. In addition to its well-known role in immune regulation, PD-L1 also plays a role in regulating cancer cell proliferation and promoting drug resistance of tumor cells, which will be reviewed in this paper. In addition, we also summarized the natural products and drugs that regulated the expression of PD-L1 in HCC.

A Comparative Study of Antitumor Immunity Induced by Radiofrequency Microwave and Cryoablation in Hepatocellular Carcinoma

PURPOSE

This study aimed to compare the immune responses induced by microwave ablation (MWA), radiofrequency ablation (RFA), and cryoablation (CRYO) in hepatocellular carcinoma (HCC) and identify differences in immune responses and the timing of immune changes.

MATERIALS AND METHODS

A bilateral subcutaneous model was established in C57 mice, and the successfully modeled mice were divided into the microwave (n = 15), radiofrequency (n = 15), CRYO (n = 15), control (n = 9), and blank groups (n = 3). Mice in the control group were dissected before ablation, whereas mice in the three ablation groups underwent ultrasound-guided ablation of one axillary tumor. Three mice were sacrificed and dissected at 1-4 weeks after ablation. After tissue processing, flow cytometry was used to detect the levels of CD8 + T and regulatory T (Treg) cells in the tissue, and western blotting was used to assess the level of programmed cell death ligand 1 (PD-L1) protein in the tumor tissue.

RESULTS

The pattern of immune changes after the three types of ablation was consistent, with immune changes occurring at 3-4 weeks. CRYO induced the most significant increase in the percentage of CD8 + T cells. There were no significant differences in the levels of Treg cells and the level of PD-L1 protein among the three types of ablation (p > 0.05), but the decline in Treg cells and PD-L1 protein level caused by CRYO was the most pronounced.

CONCLUSION

In the HCC mouse model, the immune changes following the three types of ablation were consistent, with immune changes occurring at 3-4 weeks. Among them, CRYO elicited the strongest adaptive immune response, and RFA outperformed MWA.

Combination Therapy of Immune Checkpoint Inhibitors with Locoregional Therapy for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is estimated to be the fourth leading cause of cancer-related deaths globally, and its overall prognosis is dismal because most cases are diagnosed at a late stage and are unamenable to curative treatment. The emergence of immune checkpoint inhibitors (ICIs) has dramatically improved the therapeutic efficacy for advanced hepatocellular carcinoma; however, their response rates remain unsatisfactory, partly because >50% of HCC exhibit an ICI-nonresponsive tumor microenvironment characterized by a paucity of cytotoxic T cells (immune-cold), as well as difficulty in their infiltration into tumor sites (immune excluded). To overcome this limitation, combination therapies with locoregional therapies, including ablation, transarterial embolization, and radiotherapy, which are usually used for early stage HCCs, have been actively explored to enhance ICI efficacy by promoting the release of tumor-associated antigens and cytokines, and eventually accelerating the so-called cancer-immunity cycle. Various combination therapies have been investigated in early- to late-phase clinical trials, and some have shown promising results. This comprehensive article provides an overview of the immune landscape for HCC to understand ICI efficacy and its limitations and, subsequently, reviews the status of combinatorial therapies of ICIs with locoregional therapy for HCC.

Immunotherapy and Liver Transplantation: A Narrative Review of Basic and Clinical Data

Immune checkpoint inhibitors (ICIs) have improved the management of patients with intermediate- and advanced-stage HCC, even making some of them potential candidates for liver transplantation. However, acute rejection has been observed after ICI therapy, challenging its safety in transplant settings. We summarize the key basic impact of immune checkpoints on HCC and liver transplantation. We analyze the available case reports and case series on the use of ICI therapy prior to and after liver transplantation. A three-month washout period is desirable between ICI therapy and liver transplantation to reduce the risk of acute rejection. Whenever possible, ICIs should be avoided after liver transplantation, and especially so early after a transplant. Globally, more robust prospective data in the field are required.

Decoding Immune Signature to Detect the Risk for Early-Stage HCC Recurrence

Hepatocellular carcinoma (HCC) is often recognized as an inflammation-linked cancer, which possesses an immunosuppressive tumor microenvironment. Curative treatments such as surgical resection, liver transplantation, and percutaneous ablation are mainly applicable in the early stage and demonstrate significant improvement of survival rate in most patients. However, 70-80% of patients report HCC recurrence within 5 years of curative treatment, representing an important clinical issue. However, there is no effective recurrence marker after surgical and locoregional therapies, thus, tumor size, number, and histological features such as cancer cell differentiation are often considered as risk factors for HCC recurrence. Host immunity plays a critical role in regulating carcinogenesis, and the immune microenvironment characterized by its composition, functional status, and density undergoes significant alterations in each stage of cancer progression. Recent studies reported that analysis of immune contexture could yield valuable information regarding the treatment response, prognosis and recurrence. This review emphasizes the prognostic value of tumors associated with immune factors in HCC recurrence after curative treatment. In particular, we review the immune landscape and immunological factors contributing to early-stage HCC recurrence, and discuss the immunotherapeutic interventions to prevent tumor recurrence following curative treatments.

Potential Immunotherapy Targets for Liver-Directed Therapies, and the Current Scope of Immunotherapeutics for Liver-Related Malignancies

Liver cancer, including hepatocellular carcinoma and intrahepatic cholangiocarcinoma, is increasing in incidence and mortality across the globe. An improved understanding of the complex tumor microenvironment has opened many therapeutic doors and led to the development of novel pharmaceuticals targeting cellular signaling pathways or immune checkpoints. These interventions have significantly improved tumor control rates and patient outcomes, both in clinical trials and in real-world practice. Interventional radiologists play an important role in the multidisciplinary team given their expertise in minimally invasive locoregional therapy, as the bulk of these tumors are usually in the liver. The aim of this review is to highlight the immunological therapeutic targets for primary liver cancers, the available immune-based approaches, and the contributions that interventional radiology can provide in the care of these patients.

Immunomodulatory effect of locoregional therapy in the tumor microenvironment

Cancer immunotherapy appears to be a promising treatment option; however, only a subset of patients with cancer responds favorably to treatment. Locoregional therapy initiates a local antitumor immune response by disrupting immunosuppressive components, releasing immunostimulatory damage-associated molecular patterns, recruiting immune effectors, and remodeling the tumor microenvironment. Many studies have shown that locoregional therapy can produce specific antitumor immunity alone; nevertheless, the effect is relatively weak and transient. Furthermore, increasing research efforts have explored the potential synergy between locoregional therapy and immunotherapy to enhance the long-term systemic antitumor immune effect and improve survival. Therefore, further research is needed into the immunomodulatory effects of locoregional therapy and immunotherapy to augment antitumor effects. This review article summarizes the key components of the tumor microenvironment, discusses the immunomodulatory role of locoregional therapy in the tumor microenvironment, and emphasizes the therapeutic potential of locoregional therapy in combination with immune checkpoint inhibitors.

Navigating through the PD-1/PDL-1 Landscape: A Systematic Review and Meta-Analysis of Clinical Outcomes in Hepatocellular Carcinoma and Their Influence on Immunotherapy and Tumor Microenvironment

This systematic review aimed to assess the prognostic significance of programmed cell death-ligand 1 (PDL-1) and programmed cell death protein 1 (PD-1) in hepatocellular carcinoma (HCC). Medline, EMBASE, and Cochrane Library database searches were conducted, revealing nine relevant cohort studies (seven PDL-1 and three PD-1). Our meta-analysis showed that PD-1/PDL-1 was a marker of poor survival, regardless of the assessment method (PD-1 overall survival (OS): hazard ratio (HR) 2.40; 95% confidence interval (CI), 1.30–4.42; disease-free survival (DFS): HR 2.12; 95% CI, 1.45–3.10; PDL-1: OS: HR 3.61; 95% CI, 2.75–4.75; and DFS: HR 2.74; 95% CI, 2.09–3.59). Additionally, high level of PD-1/PDL-1 expression was associated with aging, multiple tumors, high alpha-fetoprotein levels, and advanced Barcelona Clinic Liver Cancer stage. This high level significantly predicted a poor prognosis for HCC, suggesting that anti-PD-1 therapy is plausible for patients with HCC. Furthermore, HIF-1 induces PD-1 expression, and PD1lowSOCS3high is associated with a better prognosis. Taken together, combination therapy may be the key to effective immunotherapy. Thus, exploring other markers, such as HIF-1 and SOCS3, along with PD-1/PDL-1 immunotherapy, may lead to improved outcomes.

Anti-PD-L1 antibody enhances curative effect of cryoablation via antibody-dependent cell-mediated cytotoxicity mediating PD-L1highCD11b+ cells elimination in hepatocellular carcinoma

Cryoablation (CRA) and microwave ablation (MWA) are two main local treatments for hepatocellular carcinoma (HCC). However, which one is more curative and suitable for combining with immunotherapy is still controversial. Herein, CRA induced higher tumoral PD-L1 expression and more T cells infiltration, but less PD-L1^highCD11b⁺ myeloid cells infiltration than MWA in HCC. Furthermore, CRA had better curative effect than MWA for anti-PD-L1 combination therapy in mouse models. Mechanistically, anti-PD-L1 antibody facilitated infiltration of CD8⁺ T cells by enhancing the secretion of CXCL9 from cDC1 cells after CRA therapy. On the other hand, anti-PD-L1 antibody promoted the infiltration of NK cells to eliminate PD-L1^highCD11b⁺ myeloid cells by antibody-dependent cell-mediated cytotoxicity (ADCC) effect after CRA therapy. Both aspects relieved the immunosuppressive microenvironment after CRA therapy. Notably, the wild-type PD-L1 Avelumab (Bavencio), compared to the mutant PD-L1 atezolizumab (Tecentriq), was better at inducing the ADCC effect to target PD-L1^highCD11b⁺ myeloid cells. Collectively, our study uncovered the novel insights that CRA showed superior curative effect than MWA in combining with anti-PD-L1 antibody by strengthening CTL/NK cell immune responses, which provided a strong rationale for combining CRA and PD-L1 blockade in the clinical treatment for HCC.

Liver immunity, autoimmunity, and inborn errors of immunity

The liver is the front line organ of the immune system. The liver contains the largest collection of phagocytic cells in the body that detect both pathogens that enter through the gut and endogenously produced antigens. This is possible by the highly developed differentiation capacity of the liver immune system between self-antigens or non-self-antigens, such as food antigens or pathogens. As an immune active organ, the liver functions as a gatekeeping barrier from the outside world, and it can create a rapid and strong immune response, under unfavorable conditions. However, the liver's assumed immune status is anti-inflammatory or immuno-tolerant. Dynamic interactions between the numerous populations of immune cells in the liver are key for maintaining the delicate balance between immune screening and immune tolerance. The anatomical structure of the liver can facilitate the preparation of lymphocytes, modulate the immune response against hepatotropic pathogens, and contribute to some of its unique immunological properties, particularly its capacity to induce antigen-specific tolerance. Since liver sinusoidal endothelial cell is fenestrated and lacks a basement membrane, circulating lymphocytes can closely contact with antigens, displayed by endothelial cells, Kupffer cells, and dendritic cells while passing through the sinusoids. Loss of immune tolerance, leading to an autoaggressive immune response in the liver, if not controlled, can lead to the induction of autoimmune or autoinflammatory diseases. This review mentions the unique features of liver immunity, and dysregulated immune responses in patients with autoimmune liver diseases who have a close association with inborn errors of immunity have also been the emphases.

Combinatory local ablation and immunotherapies for hepatocellular carcinoma: Rationale, efficacy, and perspective

Hepatocellular carcinoma (HCC) is the leading cause of cancer-related death worldwide. Local ablation, such as radiofrequency ablation, microwave ablation, cryoablation and irreversible electroporation, etc., are well established in elimination and control of HCC. However, high recurrence rate after local ablation remains the biggest challenge for HCC management. Novel and effective therapeutic strategies to improve long-term survival are urgently needed. Accumulating studies have reported the role of ablation in modulating the tumor signaling pathway and the immune microenvironment to both eliminate residual/metastatic tumor and promote tumor progression. Ablation has been shown to elicit tumor-specific immune responses by inducing massive cell death and releasing tumor antigen. Immunotherapies that unleash the immune system have the potential to enhance the anti-tumor immunity induced by ablation. Multiple combinatory strategies have been explored in preclinical and clinical studies. In this review, we comprehensively summarize the latest progress on different mechanisms underlying the effects of ablation on tumor cells and tumor microenvironment. We further analyze the clinical trials testing the combination of ablation and immunotherapies, and discuss the possible role of immunomodulation to boost the anti-tumor effects of ablation and prevent HCC recurrence.

Ferroptosis: a double-edged sword mediating immune tolerance of cancer

The term ferroptosis was put forward in 2012 and has been researched exponentially over the past few years. Ferroptosis is an unconventional pattern of iron-dependent programmed cell death, which belongs to a type of necrosis and is distinguished from apoptosis and autophagy. Actuated by iron-dependent phospholipid peroxidation, ferroptosis is modulated by various cellular metabolic and signaling pathways, including amino acid, lipid, iron, and mitochondrial metabolism. Notably, ferroptosis is associated with numerous diseases and plays a double-edged sword role. Particularly, metastasis-prone or highly-mutated tumor cells are sensitive to ferroptosis. Hence, inducing or prohibiting ferroptosis in tumor cells has vastly promising potential in treating drug-resistant cancers. Immunotolerant cancer cells are not sensitive to the traditional cell death pathway such as apoptosis and necroptosis, while ferroptosis plays a crucial role in mediating tumor and immune cells to antagonize immune tolerance, which has broad prospects in the clinical setting. Herein, we summarized the mechanisms and delineated the regulatory network of ferroptosis, emphasized its dual role in mediating immune tolerance, proposed its significant clinical benefits in the tumor immune microenvironment, and ultimately presented some provocative doubts. This review aims to provide practical guidelines and research directions for the clinical practice of ferroptosis in treating immune-resistant tumors.

Immune checkpoint inhibitors in HCC: Cellular, molecular and systemic data

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer related deaths in the world, and for patients with advanced disease there are few therapeutic options available. The complex immunological microenvironment of HCC and the success of immunotherapy in several types of tumours, has raised the prospect of potential benefit for immune based therapies, such as immune checkpoint inhibitors (ICIs), in HCC. This has led to significant breakthrough research, numerous clinical trials and the rapid approval of multiple systemic drugs for HCC by regulatory bodies worldwide. Although some patients responded well to ICIs, many have failed to achieve significant benefit, while others showed unexpected and paradoxical deterioration. The aim of this review is to discuss the pathophysiology of HCC, the tumour microenvironment, key clinical trials evaluating ICIs in HCC, various resistance mechanisms to ICIs, and possible ways to overcome these impediments to improve patient outcomes.

Immune checkpoint silencing using RNAi-incorporated nanoparticles enhances antitumor immunity and therapeutic efficacy compared with antibody-based approaches

BACKGROUND

Cytotoxic CD8⁺ T cell-based cancer immunotherapy has been extensively studied and applied, however, tumor cells are known to evade immune responses through the expression of immune checkpoints, such as programmed death ligand 1 (PD-L1). To overcome these issues, antibody-based immune checkpoint blockades (eg, antiprogrammed cell death 1 (anti-PD-1) and anti-PD-L1) have been revolutionized to improve immune responses. However, their therapeutic efficacy is limited to 15%-20% of the overall objective response rate. Moreover, PD-L1 is secreted from tumor cells, which can interrupt antibody-mediated immune reactions in the tumor microenvironment.

METHODS

We developed poly(lactic-co-glycolic acid) nanoparticles (PLGA-NPs) encapsulating PD-L1 small interfering RNA (siRNA) and PD-1 siRNA, as a delivery platform to silence immune checkpoints. This study used the TC-1 and EG7 tumor models to determine the potential therapeutic efficacy of the PLGA (PD-L1 siRNA+PD-1 siRNA)-NPs, on administration twice per week for 4 weeks. Moreover, we observed combination effect of PLGA (PD-L1 siRNA+PD-1 siRNA)-NPs and PLGA (antigen+adjuvant)-NPs using TC-1 and EG7 tumor-bearing mouse models.

RESULTS

PLGA (PD-L1 siRNA+PD-1 siRNA)-NPs boosted the host immune reaction by restoring CD8⁺ T cell function and promoting cytotoxic CD8⁺ T cell responses. We demonstrated that the combination of NP-based therapeutic vaccine and PLGA (siRNA)-NPs resulted in significant inhibition of tumor growth compared with the control and antibody-based treatments (p<0.001). The proposed system significantly inhibited tumor growth compared with the antibody-based approaches.

CONCLUSION

Our findings suggest a potential combination approach for cancer immunotherapy using PLGA (PD-L1 siRNA+PD-1 siRNA)-NPs and PLGA (antigen+adjuvant)-NPs as novel immune checkpoint silencing agents.

Association of PD-L1 gene polymorphisms and circulating sPD-L1 levels with HBV infection susceptibility and related liver disease progression

Soluble molecules of programmed death ligand 1 (sPD-L1) are known to modulate T-cell depletion, an important mechanism of hepatitis B virus (HBV) persistence and liver disease progression. In addition, PD-L1 polymorphisms in the 3'-UTR can influence PD-L1 expression and have been associated with cancer risk, although not definitively. The purpose of this study was to investigate the association of PD-L1 polymorphisms and circulating levels of sPD-L1 in HBV infection and live disease progression. In this study, five hundred fifty-one HBV infected patients of the three clinically well-defined subgroups chronic hepatitis B (CHB, n = 186), liver cirrhosis (LC, n = 142) and hepatocellular carcinoma (HCC, n = 223) and 240 healthy individuals (HC) were enrolled. PD-L1 polymorphisms (rs2297136 and rs4143815) were genotyped by in-house validated ARMS assays. Logistic regression models were applied in order to determine the association of PD-L1 polymorphisms with HBV infection as well as with progression of related liver diseases. Plasma sPD-L1 levels were quantified by ELISA assays. The PD-L1 rs2297136 AA genotype was associated with HBV infection susceptibility (HBV vs. HC: OR = 1.6; 95%CI = 1.1-2.3; p = 0.0087) and disease progression (LC vs. CHB: OR = 1.8; 95%CI = 1.1-2.9; p = 0.018). Whereas, the rs2297136 GG genotype was a protective factor for HCC development. Plasma sPD-L1 levels were significantly high in HBV patients (p < 0.0001) and higher in the LC followed by CHB and HCC groups. High sPD-L1 levels correlated with increased liver enzymes and with advanced liver disease progression (Child-pugh C > B > A, p < 0.0001) and BCLC classification (BCLC D > C > B > A, p = 0.031). We could, for the first time, conclude that PD-L1 rs2297136 polymorphism and plasma sPD-L1 protein levels associate with HBV infection and HBV-related liver disease progression.

Combination of Ablation and Immunotherapy for Hepatocellular Carcinoma: Where We Are and Where to Go

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide and is increasing in incidence. Local ablative therapy plays a leading role in HCC treatment. Radiofrequency (RFA) is one of the first-line therapies for early local ablation. Other local ablation techniques (e.g., microwave ablation, cryoablation, irreversible electroporation, phototherapy.) have been extensively explored in clinical trials or cell/animal studies but have not yet been established as a standard treatment or applied clinically. On the one hand, single treatment may not meet the needs. On the other hand, ablative therapy can stimulate local and systemic immune effects. The combination strategy of immunotherapy and ablation is reasonable. In this review, we briefly summarized the current status and progress of ablation and immunotherapy for HCC. The immune effects of local ablation and the strategies of combination therapy, especially synergistic strategies based on biomedical materials, were discussed. This review is hoped to provide references for future researches on ablative immunotherapy to arrive to a promising new era of HCC treatment.

Clinicopathological and Prognostic Value of Programmed Cell Death 1 Expression in Hepatitis B Virus-related Hepatocellular Carcinoma: A Meta-analysis

BACKGROUND AND AIMS

The efficacy of targeted programmed cell death 1/programmed death ligand 1 (PD-1/PD-L1) monoclonal antibodies (mAbs) has been confirmed in many solid malignant tumors. The overexpression of PD-1/PD-L1 serves as a biomarker to predict prognosis and clinical progression. However, the role of PD-1 in patients with hepatitis B virus-related hepatocellular carcinoma (HBV-HCC) remains indeterminate. Given that HBV is the most important cause for HCC, this study aimed to investigate the prognostic and clinicopathological value of PD-1 in HBV-HCC via a meta-analysis.

METHODS

We searched PubMed, Embase, Scopus, the Cochrane Library, Web of Science and Google Scholar up to January 2021 for studies on the correlation between clinicopathology/prognosis and PD-1 in patients with HBV-HCC. The pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to investigate the prognostic significance of PD-1 expression. The odds ratios (ORs) and 95% CIs were determined to explore the association between PD-1 expression and clinicopathological features.

RESULTS

Our analysis included seven studies with 658 patients, which showed that high PD-1 expression was statistically correlated with poorer overall survival (HR=2.188, 95% CI: [1.262-3.115], p<0.001) and disease-free survival (HR=2.743, 95% CI: [1.980-3.506], p<0.001). PD-1 overexpression was correlated with multiple tumors (OR=2.268, 95% CI: [1.209-4.257], p=0.011), high level of alpha fetoprotein (AFP; OR=1.495, 95% CI: [1.005-2.223], p=0.047) and advanced Barcelona Clinic Liver Cancer (BCLC) stage (OR=3.738, 95% CI: [2.101-6.651], p<0.001).

CONCLUSIONS

Our meta-analysis revealed that the high level of PD-1 expression was associated with multiple tumors, high level of AFP and advanced BCLC stage. It significantly predicted a poor prognosis of HBV-HCC, which suggests that anti-PD-1 therapy for HBV-HCC patients is plausible.

Interventional Radiology Image-Guided Locoregional Therapies (LRTs) and Immunotherapy for the Treatment of HCC

Image-guided locoregional therapies (LRTs) are a crucial asset in the treatment of hepatocellular carcinoma (HCC), which has proven to be characterized by an impaired antitumor immune status. LRTs not only directly destroy tumor cells but also have an immunomodulating role, altering the tumor microenvironment with potential systemic effects. Nevertheless, the immune activation against HCC induced by LRTs is not strong enough on its own to generate a systemic significant antitumor response, and it is incapable of preventing tumor recurrence. Currently, there is great interest in the possibility of combining LRTs with immunotherapy for HCC, as this combination may result in a mutually beneficial and synergistic relationship. On the one hand, immunotherapy could amplify and prolong the antitumoral immune response of LRTs, reducing recurrence cases and improving outcome. On the other hand, LTRs counteract the typical immunosuppressive HCC microenvironment and status and could therefore enhance the efficacy of immunotherapy. Here, after reviewing the current therapeutic options for HCC, we focus on LRTs, describing for each of them the technique and data on its effect on the immune system. Then, we describe the current status of immunotherapy and finally report the recently published and ongoing clinical studies testing this combination.

Prognostic value of soluble programmed cell death-1 (sPD-1) and soluble programmed cell death ligand-1 (sPD-L1) for hepatocellular carcinoma: a systematic review and meta-analysis

BACKGROUND

Preliminary studies have suggested that soluble programmed death-1 (sPD-1) and soluble programmed cell death ligand-1 (sPD-L1) have prognostic implications in many malignant tumors. However, the correlation between sPD-1/sPD-L1 level and prognosis of hepatocellular carcinoma (HCC) is still unclear.

METHODS

We searched several electronic databases from database inception to October 7, 2021. Meta-analyses were performed separately for overall survival (OS), disease-free survival (DFS), recurrence-free survival (RFS), time to progression (TTP), and tumor-free survival (TFS). Random effects were introduced to this meta-analysis. The correlation between sPD-1/sPD-L1 level and prognosis was evaluated using hazard ratios (HRs) with 95% confidence intervals (95%CIs).

RESULTS

A total of 11 studies (1291 patients) were incorporated into this meta-analysis, including seven on sPD-L1, two on sPD-1, and two about both factors. The pooled results showed that high sPD-L1 level was associated with worse OS (HR = 2.46, 95%CI 1.74-3.49, P < 0.001; I² = 31.4, P = 0.177) and poorer DFS/RFS/TTP/TFS of patients with HCC (HR = 2.22, 95%CI 1.47-3.35, P < 0.001; I² = 66.1, P = 0.011), irrespective of method of detection, study type, treatment, cut-off value and follow-up time. In contrast, the level of sPD-1 was not correlated to the OS (HR = 1.19, 95%CI 0.55-2.56, P = 0.657) and DFS/TFS of patients with HCC (HR = 0.94, 95%CI 0.36-2.49, P = 0.906).

CONCLUSION

sPD-L1 rather than sPD-1 could be a good predictor for recurrence and survival after treatment for HCC. More high-quality prospective studies are warranted to assess the prognostic value of sPD-1 or sPD-L1 for HCC.

Case Report: Antiangiogenic Therapy Plus Immune Checkpoint Inhibitors Combined With Intratumoral Cryoablation for Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC) is a common gastrointestinal malignancy with high incidence and poor prognosis. Common treatment methods include surgery, transcatheter arterial chemoembolization (TACE), ablation, and targeted therapy. In recent years, combination treatment with antiangiogenic therapy and immune checkpoint inhibitors has made great progress in the treatment of advanced HCC. Here, we report the case of a patient with HCC who achieved a durable benefit from anti-vascular therapy and immune checkpoint inhibitors combined with intratumoral cryoablation.

Main Body

A 38-year-old male patient initially presented with severe abdominal pain that was identified as an HCC rupture and hemorrhage by computed tomography (CT). The patient underwent emergency surgery and postoperative pathology confirmed HCC. The patient received prophylactic TACE after surgery. Unfortunately, three months after surgery, the patient developed multiple liver metastases. Subsequently, he received systemic anti-vascular therapy and immune checkpoint inhibitors combined with intratumoral cryoablation. After treatment, the patient achieved extensive tumor necrosis and the disease was effectively controlled.

Conclusions

Anti-angiogenic therapy and immune checkpoint inhibitors combined with cryoablation can induce a powerful and effective systemic anti-tumor immune response, which is worthy of further research.

Immunological Markers, Prognostic Factors and Challenges Following Curative Treatments for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related mortalities worldwide. Patients with early-stage HCC are eligible for curative treatments, such as surgical resection, liver transplantation (LT) and percutaneous ablation. Although curative treatments provide excellent long-term survival, almost 70–80% of patients experience HCC recurrence after curative treatments. Tumor-related factors, including tumor size, number and differentiation, and underlying liver disease, are well-known risk factors for recurrence following curative therapies. Moreover, the tumor microenvironment (TME) also plays a key role in the recurrence of HCC. Many immunosuppressive mechanisms, such as an increase in regulatory T cells and myeloid-derived suppressor cells with a decrease in cytotoxic T cells, are implicated in HCC recurrence. These suppressive TMEs are also modulated by several factors and pathways, including mammalian target of rapamycin signaling, vascular endothelial growth factor, programmed cell death protein 1 and its ligand 1. Based on these mechanisms and the promising results of immune checkpoint blockers (ICBs) in advanced HCC, there have been several ongoing adjuvant studies using a single or combination of ICB following curative treatments in HCC. In this review, we strive to provide biologic and immunological markers, prognostic factors, and challenges associated with clinical outcomes after curative treatments, including resection, LT and ablation.

PD-1 Blockade Restores the Proliferation of Peripheral Blood Lymphocyte and Inhibits Lymphocyte Apoptosis in a BALB/c Mouse Model of CP BVDV Acute Infection

Acute infection of bovine viral diarrhea virus (BVDV) is associated with immune dysfunction and can cause peripheral blood lymphopenia and lymphocyte apoptosis. Our previous study has confirmed that programmed death-1 (PD-1) blockade inhibits peripheral blood lymphocytes (PBL) apoptosis and restores proliferation and anti-viral immune functions of lymphocytes after BVDV infection in vitro. However, the situation in vivo remains to be further studied and confirmed. Therefore, in this study, we established a BALB/c mouse model of acute BVDV infection with cytopathic (CP) BVDV (strain NADL) and non-cytopathic (NCP) BVDV (strain NY-1). Then, we examined the mRNA and protein levels of PD-1 and programmed death-ligand 1 (PD-L1) in peripheral blood mononuclear cells (PBMC) from BVDV-infected mice and analyzed the effects of PD-1 blockade on the proportions of CD3+, CD4+, and CD8+ T cell subsets, the apoptosis and proliferation of PBL, and the production of IL-2 and IFN-γ. We found that leukopenia, lymphocytopenia, and thrombocytopenia were developed in both CP and NCP BVDV-infected mice at day 7 of post-infection. The mRNA and protein expression of PD-1 and PD-L1 were significantly upregulated in CP and NCP BVDV-infected mice. Moreover, PD-1/PD-L1 upregulation was accompanied by leukopenia and lymphopenia. Additionally, PD-1 blockade inhibited PBL apoptosis and virus replication, restored the proportions of CD3+, CD4+, and CD8+ T cell subsets, and increased IFN-γ production and p-ERK expression in BVDV-infected mice. However, blocking PD-1 did not significantly affect PBL proliferation and IL-2 production in NCP BVDV-infected mice. Our findings further confirmed the immunomodulatory role of PD-1 in peripheral blood lymphocytopenia in vivo and provided a scientific basis for exploring the molecular mechanism of immune dysfunction caused by acute BVDV infection.

Immune Responses Following Locoregional Treatment for Hepatocellular Carcinoma: Possible Roles of Adjuvant Immunotherapy

Hepatocellular carcinoma (HCC) is a common cause of cancer-related deaths worldwide. Unlike other types of cancer, HCC can be treated with locoregional treatments (LRTs) such as radiofrequency ablation (RFA) or transarterial chemoembolization (TACE). However, recurrences following LRTs are common, and strategies to improve long-term outcomes need to be developed. The exhaustion of anti-tumor immunity in HCC has been well established in many reports and the immunomodulatory effects of LRTs (enhancement of tumor antigen-specific T cell responses after RFA, reduction of effector regulatory T cells after TACE) have also been reported in several previous studies. However, a comprehensive review of previous studies and the possible roles of immunotherapy following LRTs in HCC are not known. In this review, we discuss the immunological evidence of current clinical trials using LRTs and combined immunotherapies, and the possible role of this strategy.

Combination of Chidamide-Mediated Epigenetic Modulation with Immunotherapy: Boosting Tumor Immunogenicity and Response to PD-1/PD-L1 Blockade

Improving tumor immunogenicity is critical for increasing the responsiveness of triple-negative breast cancer (TNBC) to anti-PD-(L)1 treatment. Here, we verified that chidamide (CHI), an epigenetic modulator, could elicit immunogenic cell death within TNBC to enhance cancer immunogenicity and elicit an antitumor immune response. Additionally, CHI increased the expression level of PD-L1, MHC I, and MHC II on cancer cells, which contributed to T-cell recognition and PD-1/PD-L1 blockade therapy response. The synergistic antitumor efficacy of CHI and PD-L1 blockade therapy was further explored through liposomes co-delivering CHI and BMS-202 (a small-molecule PD-L1 inhibitor). The liposomes possessed good biocompatibility, security, and controllable drug release and endowed therapeutics drugs with favorable tumor accumulation. Furthermore, the drug-loaded liposomes could obviously boost the antitumor immunity of TNBC through CHI-enhanced tumor immunogenicity and BMS-202-mediated PD-L1 blockade, thereby effectively inhibiting the growth of primary and metastatic tumors with an inhibitory rate of metastasis of up to 96%. In summary, this work provided a referable and optional approach for clinical antitumor therapy based on the combination of an epigenetic modulator and PD-1/PD-L1 blockade therapy.

Immunotherapy against programmed death-1/programmed death ligand 1 in hepatocellular carcinoma: Importance of molecular variations, cellular heterogeneity, and cancer stem cells

Hepatocellular carcinoma (HCC) is a heterogeneous malignancy related to diverse etiological factors. Different oncogenic mechanisms and genetic variations lead to multiple HCC molecular classifications. Recently, an immune-based strategy using immune checkpoint inhibitors (ICIs) was presented in HCC therapy, especially with ICIs against the programmed death-1 (PD-1) and its ligand PD-L1. However, despite the success of anti-PD-1/PD-L1 in other cancers, a substantial proportion of HCC patients fail to respond. In this review, we gather current information on biomarkers of anti-PD-1/PD-L1 treatment and the contribution of HCC heterogeneity and hepatic cancer stem cells (CSCs). Genetic variations of PD-1 and PD-L1 are associated with chronic liver disease and progression to cancer. PD-L1 expression in tumoral tissues is differentially expressed in CSCs, particularly in those with a close association with the tumor microenvironment. This information will be beneficial for the selection of patients and the management of the ICIs against PD-1/PD-L1.

Inhibitors of immune checkpoints-PD-1, PD-L1, CTLA-4-new opportunities for cancer patients and a new challenge for internists and general practitioners

The treatment of cancer patients with immune checkpoint inhibitors (ICI) (anti-CTLA-4, anti-PD-1, anti-PD-L1, combined therapy anti-PD-1/PD-L1 with anti-CTLA-4) has without doubt been a significant breakthrough in the field of oncology in recent years and constitutes a major step forward as a novel type of immunotherapy in the treatment of cancer. ICIs have contributed to a significant improvement in the outcome of treatment and prognosis of patients with different types of malignancy. With the expansion of the use of ICIs, it is expected that caregivers will face new challenges, namely, they will have to manage the adverse side effects associated with the use of these drugs. New treatment options pose new challenges not only for oncologists but also for specialists in other clinical fields, including general practitioners (GPs). They also endorse the need for taking a holistic approach to the patient, which is a principle widely recognized in oncology and especially relevant in the case of the expanding use of ICIs, which may give rise to a wide variety of organ complications resulting from treatment. Knowledge and awareness of the spectrum of immune-related adverse events (irAEs) will allow doctors to qualify patients for treatment more appropriately, prevent complications, correctly recognize, and ultimately treat them. Additionally, patients with more non-specific symptoms would be expected, in the first instance, to consult their general practitioners, as complications may appear even after the termination of treatment and do not always proceed in line with disease progression. Dealing with any iatrogenic complications, will not only be the remit of oncologists but because of the likelihood that specific organs may be affected, is likely to extend also to specialists in various fields of internal medicine. These specialists, e.g., endocrinologists, dermatologists, pulmonologists, and gastroenterologists, are likely to receive referrals for patients suffering from specific types of adverse events or will be asked to provide care in cases requiring hospitalization of patients with complications in their field of expertise. In view of these considerations, we believe that there is an urgent need for multidisciplinary teamwork in the treatment of cancer patients undergoing immunotherapy and suffering the consequent adverse reactions to treatment.

Programmed cell death ligand-1 expression and survival in a cohort of patients with non-small cell lung cancer receiving first-line through third-line therapy in Denmark

BACKGROUND

PD-L1 expression on tumor cells (TCs) or immune cells (ICs) may be used as a prognostic marker for survival in patients with NSCLC. We characterized PD-L1 expression on TCs or ICs in a patient cohort with NSCLC to determine associations between PD-L1 expression and overall survival (OS), according to EGFR and KRAS mutation status.

METHODS

Danish patients aged >18 years diagnosed with NSCLC before 2014 on first- (N = 491), second- (N = 368), or third-line (N = 498) therapy were included. Data were extracted from population-based medical registries. Tumor samples from pathology archives were tested for biomarkers. High PD-L1 expression was defined as expression on ≥25 % of TCs or ICs based on first diagnostic biopsy or surgical resection. KRAS and EGFR mutation status were tested using PCR-based assays. Cox regression analysis was used to compute adjusted HRs and associated 95 % CIs.

RESULTS

PD-L1 TC and IC ≥ 25 % were observed in 24.3 %-31.0 % and 11.7-14.7 % of patients, respectively. EGFR and KRAS mutations were detected in 4.7 %-8.8 % and 26.5 %-30.7 % of patients, respectively. PD-L1 TC ≥ 25 % was not associated with survival advantage in first- (HR = 0.96, 95 % CI: 0.75-1.22), second- (1.08, 0.81-1.42), or third-line (0.94, 0.74-1.20) therapy. PD-L1 IC ≥ 25 % was associated with survival advantage in second-line (HR = 0.56, 95 % CI: 0.36-0.86) and third-line (0.69, 0.49-0.97) but not first-line (1.00, 0.70-1.41) therapy.

CONCLUSION

No association was observed between PD-L1 TC ≥ 25 % and OS in any therapy line. PD-L1 IC ≥ 25 % may confer survival benefit among some patients who reach second-line therapy.

Single sample scoring of hepatocellular carcinoma: A study based on data mining

Hepatocellular carcinoma (HCC) is a high mortality malignancy and the second leading cause of cancer-related deaths. Because the immune system plays a dual role by assisting the host barrier and tumor progression, there are complex interactions with considerable prognostic significance. Herein, we performed single-sample gene set enrichment (ssGSEA) to explore the tumor microenvironment (TME) and quantify the tumor-infiltrating immune cell (TIIC) subgroups of immune responses based on the HCC cohort of The Cancer Genome Atlas (TCGA) database. We evaluate molecular subpopulations, survival, function, and expression differential associations, as well as reveal potential targets, and biomarkers for immunotherapy. We combined the TME score and the 29 immune cell types in the low, medium, and high immunity groups. The stromal score, immune score, and ESTIMATE score were positively correlated with immune activity but negatively correlated with the tumor purity. There were 23 human leukocyte antigen (HLA)-related genes that were significantly different. However, KIAA1429 was not significant among the different immunity groups. Besides, programmed death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) expression increased with the increase of immune activity. This may provide valuable information for HCC immunotherapy. We also found that there was no significant difference in naïve B cells, macrophages M1, activated mast cells, resting natural killer (NK) cells, and T cells gamma delta among the different immunity groups. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that the differential proteins were mainly enriched in alpha-linolenic acid (ALA) metabolism, cytokine-cytokine receptor interaction, glycosaminoglycan biosynthesis-heparan sulfate/heparin, glycosphingolipid biosynthesis-ganglio series and proteasome. Our findings provide a deeper understanding of the immune scene, uncovering remarkable immune infiltration patterns of various subtypes of HCC using ssGSEA. This study advances the understanding of immune response and provides a basis for research to enhance immunotherapy.

Immunotherapy Updates in Advanced Hepatocellular Carcinoma

Simple Summary

Advanced hepatocellular carcinoma (HCC) carries a grim prognosis, which has historically been compounded by a lack of available systemic therapies. Sorafenib monotherapy was the standard of care for front-line treatment of advanced HCC for many years, despite both poor tolerability and lack of durable responses. In the past few years, there have been several clinical trials evaluating the efficacy of immune checkpoint inhibitors for advanced HCC. Use of immune checkpoint inhibitors alone, and in combination with targeted therapies, has led to improved outcomes in both treatment-naïve and subsequent line treatment of advanced HCC. Here we review the role of immunotherapy in the treatment of HCC, describe the mechanistic basis for combination with targeted therapy, and summarize the recent published data as well as ongoing clinical trials for the use of immunotherapy in the treatment of advanced HCC.

Abstract

Hepatocellular carcinoma (HCC) is the second most common cause of cancer death worldwide. HCC tumor development and treatment resistance are impacted by changes in the microenvironment of the hepatic immune system. Immunotherapy has the potential to improve response rates by overcoming immune tolerance mechanisms and strengthening anti-tumor activity in the tumor microenvironment. In this review, we characterize the impact of immunotherapy on outcomes of advanced HCC, as well as the active clinical trials evaluating novel combination immunotherapy strategies. In particular, we discuss the efficacy of atezolizumab and bevacizumab as demonstrated in the IMbrave150 study, which created a new standard of care for the front-line treatment of advanced HCC. However, there are multiple ongoing trials that may present additional front-line treatment options depending on their efficacy/toxicity results. Furthermore, the preliminary data on the application of chimeric antigen receptor (CAR-T) cell therapy for treatment of HCC suggests this may be a promising option for the future of advanced HCC treatment.

Immunotherapy and predictive immunologic profile: the tip of the iceberg

The interplay between cancer and the immune system has been under investigation for more than a century. Immune checkpoint inhibitors have changed the outcome of several tumors; however, there is a significant percentage of patients presenting resistance to immunotherapy. Besides the action mechanism, it is essential to unravel this complex interplay between host immune system and tumorigenesis to determine an immune profile as a predictive factor to immune checkpoint blockade agents. Tumor expression of programmed death-ligand 1 (PD-L1), tumor mutational burden, or mismatch repair deficiency are recognized predictive biomarkers to immunotherapy but are insufficient to explain the response rates and heterogeneity across tumor sites. Therefore, it is crucial to explore the role of the tumor microenvironment in the diversity and clonality of tumor-infiltrating immune cells since different checkpoint molecules play an influential role in cytotoxic T cell activation. Moreover, cytokines, chemokines, and growth factors regulated by epigenetic factors play a complex part. Peripheral immune cells expressing PD-1/PD-L1 and the biologic roles of soluble immune checkpoint molecules are the subject of new lines of investigation. This article addresses some of the new molecules and mechanisms studied as possible predictive biomarkers to immunotherapy, linked with the concept of immune dynamics monitoring.

Expression of Immune Checkpoint Regulators, Cytotoxic T-Lymphocyte Antigen-4, and Programmed Death-Ligand 1 in Epstein-Barr Virus-associated Nasopharyngeal Carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC) is the most common cancer arising from the nasopharynx with a poor prognosis. Targeting immune checkpoint is one of the new promising lines in cancer treatment. Cytotoxic T-lymphocyte antigen-4 (CTLA-4) and programmed death-ligand 1 (PD-L1) are immune checkpoints that regulate T-cell immune function.

AIM

This work aimed to assess the immunohistochemical expression of PD-L1 and CTLA-4 in NPC and their ability to predict survival and response therapy and to check their validity as immunotherapy targets. Twenty-six cases of NPC were studied by immunohistochemistry for PD-L1 and CTLA-4 and by nested polymerase chain reaction followed by DNA sequencing for the presence of EBNA-1 gene of Epstein-Barr virus (EBV). All investigated cases were diagnosed and treated in the Zagazig University Hospital in the period from August 2015 to July 2018. EBNA-1 gene was identified in 84.6% of the cases. Whereas the expression of PD-L1 was noted in 46.2% of all cases studied, 54.6% of EBV-associated NPCs were found to express PD-L1. There was a significant association between PD-L1 expression and the advanced stage of the tumor (P<0.001). CTLA-4 expression was observed in 88.4% of all NPC cases as cytoplasmic staining in both tumor cells and tumor-infiltrating lymphocytes. CTLA-4 expression in lymphocytes was associated with the presence of EBV. A significant association was detected between CTLA-4 and tumor-infiltrating lymphocyte expression on one side and the stage of the tumor on the other. High expression of CTLA-4 was significantly associated with disease progression and worse overall survival.

CONCLUSION

PD-L1 and CTLA-4 are adverse prognostic markers in NPC. The authors propose that targeted therapy against PD-L1 and CTLA-4 will be a hopeful therapy for cases of NPC with resistance to concurrent chemoradiation treatment in Egypt, especially EBV-associated cases.

The Extrinsic and Intrinsic Roles of PD-L1 and Its Receptor PD-1: Implications for Immunotherapy Treatment

Programmed death-ligand 1 (PD-L1) is an immune checkpoint inhibitor that binds to its receptor PD-1 expressed by T cells and other immune cells to regulate immune responses; ultimately preventing exacerbated activation and autoimmunity. Many tumors exploit this mechanism by overexpressing PD-L1 which often correlates with poor prognosis. Some tumors have also recently been shown to express PD-1. On tumors, PD-L1 binding to PD-1 on immune cells promotes immune evasion and tumor progression, primarily by inhibition of cytotoxic T lymphocyte effector function. PD-1/PD-L1-targeted therapy has revolutionized the cancer therapy landscape and has become the first-line treatment for some cancers, due to their ability to promote durable anti-tumor immune responses in select patients with advanced cancers. Despite this clinical success, some patients have shown to be unresponsive, hyperprogressive or develop resistance to PD-1/PD-L1-targeted therapy. The exact mechanisms for this are still unclear. This review will discuss the current status of PD-1/PD-L1-targeted therapy, oncogenic expression of PD-L1, the new and emerging tumor-intrinisic roles of PD-L1 and its receptor PD-1 and how they may contribute to tumor progression and immunotherapy responses as shown in different oncology models.

Prognostic Value of Immune Environment Analysis in Small Bowel Adenocarcinomas with Verified Mutational Landscape and Predisposing Conditions

Background: Small bowel adenocarcinoma (SBA) is a rare yet insidious cancer with poor survival. The abundance of tumour-infiltrating lymphocytes is associated with improved survival, but the role of the programmed death-1/programmed death ligand-1 (PD-1/PD-L1) pathway in tumour escape is controversial. We evaluated immune cell infiltration, PD1/PD-L1 expression and their prognostic value in a series of SBAs with previously verified predisposing conditions and exome-wide somatic mutation characterization. Methods: Formalin-fixed paraffin-embedded tissue sections stained for CD3, CD8, PD-L1 and PD-1 were analysed from 94 SBAs. An immune cell score (ICS) was formed from the amount of the CD3 and CD8 positive lymphocytes from the tumour centre and invasive margin. The PD-L1 and PD-1 positive immune cells (ICs) and ICS were combined into a variable called Immunoprofile. Results: High ICS, PD-L1^IC and PD-1, individually and combined as Immunoprofile, were prognostic for better patient outcome. Sixty-five (69%) SBAs expressed ≥1% positive PD-L1^IC. A high tumour mutation burden was common (19%) and associated with immune markers. Immunoprofile, adjusted for TNM stage, mismatch repair status, tumour location, sex and age were independent prognostic markers for disease-specific and overall survival. Conclusions: Analysing tumoral immune contexture provides prognostic information in SBA. Combining ICS, PD-1 and PD-L1^IC as Immunoprofile enhanced the prognostic performance.

Prognostic relevance of programmed cell death protein 1/programmed death-ligand 1 pathway in thymic malignancies with combined immunohistochemical and biomolecular approach

BACKGROUND

The aim of the study was to investigate Programmed cell Death protein 1 (PD-1) and Programmed Death-Ligand 1 (PD-L1) and their mRNA expression in thymic epithelial tumors (TETs).

RESEARCH DESIGN AND METHODS

We analyzed 68 samples of formalin-fixed paraffin-embedded tissue (63 thymomas and 5 thymic carcinomas). PD-1 and PD-L1 protein expression were evaluated by immunohistochemistry, and mRNA expression was evaluated by real-time PCR.

RESULTS

M/F ratio was 33/35, and median age was 60.5 years. Twenty patients had Myasthenia Gravis (MG). In the subgroup with large tumors (>5 cm), PD-L1 mRNA overexpression was significantly associated with worse prognosis vs. patients with no mRNA overexpression (p = 0.0083) and simultaneous PD-L1 immunostaining (>1%); PD-L1 mRNA overexpression was significantly associated with worse prognosis, respect to patient with PD-L1 negative immunostaining, and no PD-L1 mRNA overexpression (p = 0.0178). The elderly patients (>60 years) with large tumors showed worse prognosis (p = 0.0395). PD-L1 immunostaining (>50%) resulted to be significantly associated with MG.

CONCLUSIONS

Our data suggest the potential involvement of the PD-1 and PD-L1 pathway in TETs' progression. According to our results, it may be helpful to design future trials with anti-PD-1 drugs to establish high-risk patients after surgery.

Hepatocellular carcinoma, novel therapies on the horizon

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and is associated with high mortality rate. Incidence remains high due to the persistent prevalence of viral hepatitis, alcoholic cirrhosis, and non-alcoholic fatty liver disease (NFLD). Despite screening efforts, the majority of patients present with advanced disease, add to the high risk of recurrence after curative surgery. Conventional chemotherapy did not alter the nature history of advanced and metastatic HCC. The discovery of multiple tyrosine kinase inhibitors (TKIs) led to the approval of sorafenib as first efficacious therapy. A new era in the treatment paradigm of HCC is evolving. Since the advent of sorafenib as an active treatment option for patients presenting with advanced or metastatic disease, several agents have been examined. This was linked with many failures, and success stories to celebrate. Herein, we describe the historical progress and current advances of systemic therapies post-sorafenib. Lenvatinib, regorafenib, cabozantinib, ramucirumab, pembrolizumab, and nivolumab, are all presently added and available therapeutic options in the advanced setting. The evaluation of novel treatment combinations including anti-angiogenic, TKIs plus checkpoint inhibitors, add to dual checkpoint inhibitors is evolving rapidly starting with the advent of the combination of atezolizumab plus bevacizumab. Combining local and systemic therapies is being actively investigated, as an option for locally advanced disease conventionally treated with locoregional approaches. The horizon remains promising and continues to evolve for HCC a disease long considered with unmet needs.

Anti-PD-1/PD-L1 Blockade Immunotherapy Employed in Treating Hepatitis B Virus Infection-Related Advanced Hepatocellular Carcinoma: A Literature Review

Hepatitis B virus (HBV) infection is regarded as the main etiological risk factor in the process of hepatocellular carcinoma (HCC), as it promotes an immunosuppressive microenvironment that is partially mediated by the programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) signaling pathway. The tumor microenvironment (TME) of HBV-related HCC is indeed more immunosuppressive than microenvironments not associated with viruses. And compared to TME in hepatitis C virus (HCV) infected HCC, TME of HBV-related HCC is less vascularized and presents different immune components resulting in similar immunosuppression. However, few studies are focusing on the specific side effects and efficacy of PD-1/PD-L1 blockade immunotherapy in HBV-related HCC patients, as well as on the underlying mechanism. Herein, we reviewed the basic research focusing on potential TME alteration caused by HBV infection, especially in HCC patients. Moreover, we reviewed PD-1/PD-L1 blockade immunotherapy clinical trials to clarify the safety and efficacy of this newly developed treatment in the particular circumstances of HBV infection. We found that patients with HBV-related HCC displayed an acceptable safety profile similar to those of non-infected HCC patients. However, we could not determine the antiviral activity of PD-1/PD-L1 blockade because standard anti-viral therapies were conducted in all of the current clinical trials, which made it difficult to distinguish the potential influence of PD-1/PD-L1 blockade on HBV infection. Generally, the objective response rates (ORRs) of PD-1/PD-L1 blockade immunotherapy did not differ significantly between virus-positive and virus-negative patients, except that disease control rates (DCRs) were obviously lower in HBV-infected HCC patients.

Establishing peripheral PD-L1 as a prognostic marker in hepatocellular carcinoma patients: how long will it come true?

BACKGROUND

The prognostic role of intratumoral programmed cell death ligand 1 (PD-L1) expression in hepatocellular carcinoma (HCC) has been investigated by several meta-analyses. However, the prognostic value of pretreatment peripheral PD-L1 (PPPD-L1) level in HCC remains undetermined. Thus, this systemic review aimed to establish PPPD-L1 as a new prognostic marker in HCC according to available evidence.

METHODS

Case-control studies investigating the prognostic role of PPPD-L1 in HCC were systemically sought in the database of PubMed and Web of Science until March 25th, 2020. Our main concern is survival results, including overall survival (OS), disease-free survival (DFS), and progression-free survival (PFS). The combined results were summarized in narrative form according to data extracted from each included study.

RESULTS

Finally, nine studies published from 2011 to 2019, were incorporated into this systemic review. Among these, six studies evaluated the PD-L1 expression by enzyme-linked immunosorbent assay (ELISA) from blood serum, and three studies evaluated the PD-L1 expression by flow cytometric analysis from peripheral blood mononuclear cells (PBMC). According to the extracted evidence, high PPPD-L1 expression, measured in either blood serum or PBMC, is associated with poor OS, poor DFS, and poor PFS. Meanwhile, PPPD-L1 was also correlated with enlarged tumor size and more likely with advanced tumor stage as well as vascular invasion.

CONCLUSION

High PPPD-L1 level is associated with increased mortality rate and increased recurrence rate in HCC. As a convenient serum marker, PPPD-L1 could be a promising marker of prognosis in HCC patients.

Prognostic value of programmed cell death ligand 1 (PD-L1) for hepatocellular carcinoma: a meta-analysis

The prognostic role of programmed death ligand-1 (PD-L1) expression in hepatocellular carcinoma (HCC) has been widely studied but the results are controversial. In this comprehensive meta-analysis, we elucidated the clinical value of PD-L1 in HCC. Relevant studies were systematically searched in the Cochrane Library, EMBASE, and PubMed until June 27, 2019. Eligible studies were validated for the prognostic effect of PD-L1 on the overall survival (OS), disease-free survival (DFS), and relapse-free survival (RFS) in HCC using a hazard ratio (HR) and its 95% confidence interval (95% CI). Twenty-three studies with 3529 patients were involved in this meta-analysis. The pooled results revealed that high membrane-bound PD-L1 (mPD-L1) expression was associated with poor OS (HR: 1.42; 95% CI: 1.12-1.80; P = 0.004) and had no significant correlation with RFS (HR: 1.14; 95% CI: 0.85-1.54; P = 0.39), and DFS (HR: 1.36; 95% CI: 0.81-2.28; P = 0.25). The results also indicated that high soluble PD-L1 (sPD-L1) levels were associated with worse OS (HR: 2.93; 95% CI: 2.20-3.91; P < 0.00001). In addition, high mPD-L1 expression was associated with high alpha-fetoprotein levels (AFP; OR = 1.46; 95% CI: 1.16-1.84; P = 0.001), hepatitis (OR = 0.72; 95% CI: 0.54-0.98; P = 0.03), poor tumor differentiation (OR = 0.68; 95% CI: 0.55-0.84; P = 0.03), and tumor-infiltrating lymphocytes (OR = 3.39; 95% CI: 1.06-10.91; P = 0.04). The mPD-L1 expression had no significant correlation with age, number of tumors, gender, tumor size, liver cirrhosis, vascular invasion, tumor encapsulation, or TNM stage. The study revealed that high mPD-L1 expression in the tumor tissue and high sPD-L1 levels were associated with shorter OS in HCC. Moreover, overexpression of mPD-L1 was significantly associated with poor tumor differentiation, hepatitis, AFP elevation, and tumor-infiltrating lymphocytes.

Liver, Tumor and Viral Hepatitis: Key Players in the Complex Balance Between Tolerance and Immune Activation

Liver cancer is the third most common cause of cancer related death in the World. From an epidemiological point of view the risk factors associated to primary liver cancer are mainly viral hepatitis infection and alcohol consumption. Even though there is a clear correlation between liver inflammation, cirrhosis and cancer, other emerging liver diseases (like fatty liver) could also lead to liver cancer. Moreover, the liver is the major site of metastasis from colon, breast, ovarian and other cancers. In this review we will address the peculiar status of the liver as organ that has to balance between tolerance and immune activation. We will focus on macrophages and other key cellular components of the liver microenvironment that play a central role during tumor progression. We will also discuss how current and future therapies may affect the balance toward immune activation.

Clinical significance of circulating soluble immune checkpoint proteins in sorafenib-treated patients with advanced hepatocellular carcinoma

In hepatocellular carcinoma (HCC), the clinical significance of soluble immune checkpoint protein levels as predictors of patient outcomes or therapeutic responses has yet to be defined. This study profiled the baseline levels of sixteen soluble checkpoint proteins and their changes following sorafenib treatment for HCC. Plasma samples were obtained from 53 patients with advanced HCC at baseline, week 1, 2 and 4 of sorafenib treatment and tested the concentrations of 16 soluble checkpoint proteins using multiplexed fluorescent bead-based immunoassays. Multivariate analysis showed high sBTLA levels at baseline were an independent predictor of poor overall survival (p = 0.038). BTLA was highly expressed in T cells and macrophages in peritumoral areas. At week 2, sCD27 levels were decreased compared to baseline. By contrast, the concentrations of most inhibitory proteins, including sBTLA, sLAG-3, sCTLA-4, sPD-1, sCD80, sCD86 and sPD-L1, had significantly increased. The fold-changes of soluble checkpoint receptors and their ligands, including sCTLA-4 with sCD80/sCD86, sPD-1 with sPD-L1; and the fold-changes of sCTLA-4 with sBTLA or sPD-1 were positively correlated. sBTLA may be a good biomarker for predicting overall survival in HCC patients. Sorafenib treatment in patients with advanced HCC revealed dynamic changes of soluble checkpoint protein levels.

The future of cryoablation: An abscopal effect

Cryoablation has become a popular modality to treat a variety of malignant tumors in solid organs and soft tissues. In the future, the use of cryoablation should focus on its abscopal effect. The present review discusses the increased immune response triggered by cryoablation alone or by cryoablation combined with immunotherapies, which can improve the immune response and limit immunosuppression. First, cryoablative techniques should be improved to increase the area of necrosis and reduce the area of apoptosis. Second, cryoablation should be combined with immunotherapies, for example, cyclophosphamide, natural killer cells, granulocyte monocyte colony stimulating factor (GM-CSF), cytotoxic T lymphocyte-associated antigen (CTLA)-4, and programmed death receptor 1 (PD)-1 inhibitors. Cryoablation could also be combined with Hydrogen gas molecules, which were shown recently to stimulate peroxisome proliferator activated receptor gamma coactivator (PGC)-1α, thereby promoting mitochondrial function, which might rescue exhausted CD8⁺ T cells, leading to prolonged progression-free survival and overall survival of patients with advanced colorectal cancer.

The Immune Modulation Effect of Locoregional Therapies and Its Potential Synergy with Immunotherapy in Hepatocellular Carcinoma

Locoregional therapies (LRTs) including radiofrequency ablation, surgical resection, and TACE, play a pivotal role in the treatment of early stage/locally advanced hepatocellular carcinoma (HCC). Besides their direct effect on tumor cells, LRTs also play an essential role in the immunomodulation of the tumor microenvironment which is of interest in the current era of cancer immunotherapy. In this review, we describe the HCC immune microenvironment and how it is affected by LRTs as described in multiple pre-clinical and clinical studies and provide the rationale for combining LRTs with immunotherapy.

PD-1+ TIGIT+ CD8+ T cells are associated with pathogenesis and progression of patients with hepatitis B virus-related hepatocellular carcinoma

Hepatitis B virus-associated hepatocellular carcinoma (HBV-HCC) is usually considered an inflammation-related cancer associated with chronic inflammation triggered by exposure to HBV and tumor antigens. T-cell exhaustion is implicated in immunosuppression of chronic infections and tumors. Although immunotherapies that enhance immune responses by targeting programmed cell death-1(PD-1)/PD-L1 are being applied to malignancies, these treatments have shown limited response rates, suggesting that additional inhibitory receptors are also involved in T-cell exhaustion and tumor outcome. Here, we analyzed peripheral blood samples and found that coexpression of PD-1 and T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT) was significantly upregulated on CD4⁺ and CD8⁺ T cells from patients with HBV-HCC compared with those from patients with chronic HBV or HBV-liver cirrhosis. Additionally, PD-1⁺ TIGIT⁺ CD8⁺ T-cell populations were elevated in patients with advanced stage and progressed HBV-HCC. Importantly, PD-1⁺ TIGIT⁺ CD8⁺ T-cell populations were negatively correlated with overall survival rate and progression-free survival rates. Moreover, we showed that PD-1⁺ TIGIT⁺ CD8⁺ T cells exhibit features of exhausted T cells, as manifested by excessive activation, high expression of other inhibitory receptors, high susceptibility to apoptosis, decreased capacity for cytokine secretion, and patterns of transcription factor expression consistent with exhaustion. In conclusion, PD-1⁺ TIGIT⁺ CD8⁺ T-cell populations are associated with accelerated disease progression and poor outcomes in HBV-HCC, which might not only have important clinical implications for prognosis but also provide a rationale for new targets in immunotherapy.