Programmed Cell Death Ligand 1 Levels Research Articles

Analysis of Treatment Response With Proteins Related to Tumor Immunity in Postoperative Irradiated Cervical Cancer Patients.

This study evaluated the association between programmed cell death-ligand 1 (PD-L1) and prognosis in patients with cervical cancer treated with postoperative radiation and the impact of neoadjuvant chemotherapy (NAC) on this association. Immunohistochemical analysis was performed on biopsy specimens from 42 patients who did not receive NAC and from paired samples before (biopsies) and after (resected tissues) chemotherapy from 46 patients who received NAC to determine the association of PD-L1 with radiotherapy outcomes. In the non-NAC group, patients with ≥10% PD-L1-expressing tumor cells prior to treatment had better recurrence-free survival (RFS) than those with <10% PD-L1-expressing tumor cells (p=0.001). In the NAC group, RFS was significantly lower (p=0.005) in the group with a ≥5% reduction of PD-L1 expression in tumor cells after chemotherapy than in those with <5% reduction. In multivariate analysis, only PD-L1 expression (non-NAC group) and the change in PD-L1 expression (NAC group) were associated with RFS. Low PD-L1 expression in a cervical tumor prior to treatment was identified as a risk factor for a poor outcome after postoperative radiotherapy. Furthermore, NAC induces an immunological shift that reduces PD-L1 levels in tumor cells, thereby negatively impacting treatment outcomes.

Programmed Cell Death Ligand 1 (PD-L1) Immunohistochemical Expression in Advanced Urothelial Bladder Carcinoma: An Updated Review with Clinical and Pathological Implications.

The management of advanced bladder carcinoma involves a multidisciplinary approach, but the prognosis remains poor for many patients. The immune system plays a crucial role in this disease, influencing both tumor development and response to treatment, and exploiting the immune system against the tumor can be a valuable strategy to destroy neoplastic cells. This is the biological principle underlying Bacillus Calmette-Guérin (BCG) use and, more recently, immune checkpoint inhibitors (ICIs), like PD-1 (programmed death-1)/PD-L1 (programmed death-ligand 1) inhibitors. In fact, one of the best studied immune checkpoints is represented by the PD-1/PD-L1 axis, which is a well-known immune escape system adopted by neoplastic bladder cells. PD-L1 expression has been associated with a higher pathologic stage and has shown prognostic value in bladder carcinoma. Interestingly, high-grade bladder cancers tend to express higher levels of PD-1 and PD-L1, suggesting a potential role of such an axis in mediating disease progression. Immunotherapy with PD-1 and PD-L1 inhibitors has therefore emerged as a valuable treatment option and has shown efficacy in advanced bladder cancer patients, with high PD-L1 expression levels associated with better treatment responses. Our review aims to provide a comprehensive overview of the role of PD-L1 in advanced bladder cancer, focusing on its implications for treatment decisions and the prediction of treatment response. Overall, our work aims to contribute to the understanding of PD-L1 as a predictive biomarker and highlight its role in shaping therapeutic approaches for advanced bladder cancer.

Synergistic upregulation of PD‑L1 in tumor cells and CD39 in tumor‑infiltrating CD8+ T cells leads to poor prognosis in patients with hepatocellular carcinoma.

The immune escape of tumor cells and functional status of tumor-infiltrating T cells may serve pivotal roles in the tumor immune microenvironment and progression of hepatocellular carcinoma (HCC). The present study enrolled 91 patients with HCC and examined programmed cell death ligand 1 (PD-L1) expression in tumor cells and CD39 expression in tumor-infiltrating CD8+ T cells in patient samples using multiplex immunofluorescence assays. The impact of PD-L1 and CD39 expression levels on the prognosis of patients with HCC was investigated utilizing Kaplan-Meier analyses. The individual upregulation of PD-L1 in tumor cells, as well as the individual upregulation of CD39 expression in tumor-infiltrating CD8+ T cells did not significantly affect the prognosis of patients with HCC. However, the simultaneous upregulation of both PD-L1 in tumor cells and CD39 in tumor-infiltrating CD8+ T cells was associated with reduced overall survival in patients with HCC. Therefore, the results of the present study suggested that the interplay between tumor cell immune escape and tumor-infiltrating immune cell functional status within the tumor immune microenvironment may have had a substantial impact on the prognosis of patients with HCC. Mechanistically, increased expression levels of PD-L1 in tumor cells may improve the immune escape capacity of tumors, whilst upregulation of CD39 in tumor-infiltrating T cells may be associated with T cell exhaustion. Therefore, the upregulation of PD-L1 expression in tumor cells, in conjunction with the exhaustion of tumor-infiltrating CD8+ T cells, could serve as a future potential prognostic indicator of patients with HCC.

PD-L1 expression in patients with non-small-cell lung cancer is associated with sex and genetic alterations: A retrospective study within the Caucasian population.

Programmed cell death-ligand 1 (PD-L1) expression is a well-established biomarker for predicting responses to immune checkpoint inhibitors and certain targeted therapies. As a result, treatment strategies for patients vary based on their PD-L1 expression status. Understanding the clinical features of patients with distinct PD-L1 levels is crucial for personalized treatment approaches. Demographic and clinicopathological characteristics of 227 patients (54% male, mean age 67 ± 9.9 years) newly diagnosed with non-small-cell lung cancer (NSCLC) between April 2020 and December 2022 were retrospectively compared among three groups based on the PD-L1 expression: PD-L1 Tumor Proportion Score (TPS) negative, 1-50%, and ≥50%. Logistic regression analysis was performed to evaluate predictors for high PD-L1 expression ≥50%. PD-L1 expression levels were distributed as follows: negative in 29% of patients, between 1% and 50% in 41%, and greater than 50% (high) in 29%. In comparison to negative PD-L1 expression, low and high PD-L1 expression was associated with female sex (32.9% vs. 52.7% vs. 50.7%, p = 0.031), with the absence of epidermal growth factor receptor (EGFR) mutations (83.6% vs. 91.1% vs. 98.1% p = 0.029), and with the absence of ERBB2 (HER2) tyrosine kinase mutations (90.9% vs. 100% vs. 98.1% p = 0.007), respectively. Age, smoking status, histological subtype, and disease stage showed no significant differences among the three patient groups. In the univariate logistic regression, EGFR mutation appeared to be the only predictor for PD-L1 expression, although it did not reach statistical significance (p = 0.06). Although sex and genomic alterations are associated with PD-L1 expression in patients with NSCLC, no clinical characteristics seem to predict PD-L1 expression significantly.

A Mesoporous Gold Sensor Unveils Phospho PD-L1 in Extracellular Vesicles as a Proxy for PD-L1 Expression in Lung Cancer Tissue.

Immune checkpoint inhibitors (ICIs) targeting programmed cell death ligand 1 (PD-L1), or its receptor, PD-1 have improved survival in patients with non-small-cell lung cancer (NSCLC). Assessment of PD-L1 expression requires tissue biopsy or fine needle aspiration that are currently used to identify patients most likely to respond to single agent anti-PD-1/PD-L1 therapy. However, obtaining sufficient tissue to generate a PD-L1 tissue proportion score (TPS) ≥ 50% using immunohistochemistry remains a challenge that potentially may be overcome by liquid biopsies. This study utilized a mesoporous gold sensor (MGS) assay to examine the phosphorylation status of PD-L1 in plasma extracellular vesicles (EV pPD-L1) and PD-L1 levels in plasma from NSCLC patient samples and their association with tumor PD-L1 TPS. The 3-dimensional mesoporous network of the electrodes provides a large surface area, high signal-to-noise ratio, and a superior electro-conductive framework, thereby significantly improving the detection sensitivity of PD-L1 nanosensing. Test (n = 20) (Pearson's r = 0.99) and validation (n = 45) (Pearson's r = 0.99) cohorts show that EV pPD-L1 status correlates linearly with the tumor PD-L1 TPS assessed by immunohistochemistry irrespective of the tumor stage, with 64% of patients overall showing detectable EV pPD-L1 levels in plasma. In contrast to the EV pPD-L1 results, plasma PD-L1 levels did not correlate with the tumor PD-L1 TPS score or EV pPD-L1 levels. These data demonstrate that EV pPD-L1 levels may be used to select patients for appropriate PD-1 and PD-L1 ICI therapy regimens in early, locally advanced, and advanced NSCLC and should be tested further in randomized controlled trials. Most importantly, the assay used has a less than 24h turnaround time, facilitating adoption of the test into the routine diagnostic evaluation of patients prior to therapy.

Distribution characteristics and prognosis of tumor-infiltrating lymphocytes in the brain metastases of small cell lung cancer: a retrospective cohort study.

The efficacy of immunotherapy for brain metastases from small cell lung cancer (SCLC) is relatively low, and the tumor microenvironment of SCLC brain metastases is still unknown. Therefore, we investigated the distribution of tumor-infiltrating lymphocytes (TILs) and the expression of programmed cell death-ligand 1 (PD-L1) in patients with brain metastases from SCLC to explore the tumor microenvironment of SCLC brain metastases. A retrospective analysis was performed on 12 surgical specimens of brain metastases from patients with SCLC treated in the Department of Neurosurgery of The First Affiliated Hospital of Anhui Medical University from June 2017 to June 2022. The inclusion criteria for this study were the following: (I) a pathologically confirmed diagnosis of SCLC brain metastases; (II) surgical resection of brain metastases; (III) age >18 years; (IV) and complete clinical data. Patient-related data were retrieved from the inpatient medical record system, telephone follow-up of patients date of death, and overall survival (OS). The immunofluorescence-based tissue microenvironment analysis panel (MAP) was utilized for the detection of TILs, including CD3, CD8, programmed cell death 1 (PD-1), and PD-L1, in formalin-fixed and paraffin-embedded archival specimens of brain metastases. The expression levels of PD-L1 in tumor cells were detected by immunohistochemistry. The correlation between the OS and the above-mentioned markers was analyzed in the 12 patients. Twelve patients were included in the study. The patients' ages ranged from 51-78 years with a median of 68 years, with 1 female and 11 males. Among 12 patients with SCLC brain metastases: positive rates of CD3+ TILs in the tumor parenchyma vs. tumor stroma were 0.60%±0.94% vs. 1.76%±2.72% (P=0.01), respectively; positive rates of CD8+ TILs in the tumor parenchyma vs. tumor stroma were 0.80%±0.78% vs. 2.46%±3.72% (P=0.02), respectively. There was no co-expression of CD8+ and PD-1+ TILs in the tumor parenchyma of 11 cases, and the infiltration density of coexpressed CD3+ and PD-1+ TILs was more than 10/mm2 in only 1 case. There was no coexpression of CD3+ and PD-1+ TIL in the stroma of 10 cases, and the infiltration density of CD8+ and PD-1+ TILs was more than 10/mm2 in 2 cases. Immunohistochemistry was used to detect the expression of PD-L1 in 12 cases of SCLC metastatic lesions, and 3 cases (25%) were positive. Survival analysis showed that patients with positive intraepithelial CD3+ TILs had significantly longer OS [hazard ratio 3.383, 95% confidence interval (CI): 0.959-11.940; P=0.04]. Our study further demonstrated the immune microenvironment of SCLC brain metastases. The distribution of TILs in SCLC brain metastases is low and mainly distributed in the stroma, with the expression of PD-L1 in these tumor tissues being low. Further exploration of the immune microenvironment of SCLC brain metastases is of great significance for potential treatment.

Association of PD-L1 expression and clinical outcomes in ROS1 - rearranged advanced non-small cell lung cancer treated with crizotinib.

Programmed cell death ligand 1 (PD-L1) is more readily expressed in ROS proto-oncogene 1 (ROS1) rearranged non-small cell lung cancer (NSCLC) compared to NSCLC cases lacking driver gene mutations. Prior research has established a link between PD-L1 expression and reduced effectiveness of EGFR or ALK inhibitors in EGFR or ALK-positive NSCLC. Nonetheless, the relationship between initial PD-L1 levels and the clinical impact of first-line crizotinib therapy in ROS1-rearranged NSCLC is still uncertain. From January 2016 to December 2021, a total of 246 patients with ROS1 positive tumors were collected. Out of these, 82 patients with advanced ROS1-rearranged NSCLC, who were treated with crizotinib as their initial therapy, were selected for the study. The study aimed primarily to evaluate the objective response rate (ORR) and progression-free survival (PFS), and secondarily to assess disease control rate (DCR) and overall survival (OS). Of the 82 advanced ROS1-rearranged NSCLC patients, 38 exhibited PD-L1 positivity, subdivided into 11 with high and 27 with low expression levels, while the remaining 44 showed no PD-L1 expression. The ORR for all included patients was 80.5%. No statistically significant variance in ORR was observed among ROS1-rearranged NSCLC patients across differing PD-L1 expression statuses. However, there was a statistically significant difference in DCR between PD-L1 negative group (100%) and high expression group (90.9%) (p=0.04). The median PFS spanned 26.4 months for the PD-L1 negative group, 16.6 for the low expression group, and 13.7 for the high expression group (p=0.001). Additionally, a notable statistical disparity was also observed in median PFS between the PD-L1 negative and positive groups (p=0.02). For the entire study population, the median OS was 53.0 months (95% CI 43.8 - 62.2). In the PD-L1-negative group, the median OS reached 57.2 months, compared to 53.0 months in the PD-L1-positive group, a difference lacking statistical significance (p=0.43). Our results suggest that for ROS1-positive NSCLC patients receiving crizotinib as first-line therapy, PD-L1 expression may serve as a negative prognostic marker for PFS rather than OS.

MEN1 deficiency stabilizes PD-L1 and promotes tumor immune evasion of lung cancer.

Multiple Endocrine Neoplasia 1 gene (MEN1), which is known to be a tumor suppressor gene in lung tissues, encodes a 610 amino acid protein menin. Previous research has proven that MEN1 deficiency promotes the malignant progression of lung cancer. However, the biological role of this gene in the immune microenvironment of lung cancer remains unclear. In this study, we found that programmed cell death-ligand 1 (PD-L1) is upregulated in lung-specific KrasG12D mutation-induced lung adenocarcinoma in mice, after Men1 deficiency. Simultaneously, CD8+ and CD3+ T cells are depleted, and their cytotoxic effects are suppressed. Invitro, PD-L1 is inhibited by the overexpression of menin. Mechanistically, we found that MEN1 inactivation promotes the deubiquitinating activity of COP9 signalosome subunit 5 (CSN5) and subsequently increases the level of PD-L1.

Combined approach for predicting the efficacy of nivolumab in head and neck carcinoma by tissue and soluble expressions of PD-L1 and PD-L2.

Predictive biomarkers for nivolumab in recurrent or metastatic head and neck squamous cell carcinoma (RMHNSCC) have not yet been established. The tumor proportion score (TPS), combined positive score (CPS), and soluble forms of programmed cell death ligand-1 (PD-L1) and programmed cell death ligand-2 (PD-L2) were retrospectively analyzed in patients with RMHNSCC treated with nivolumab. The positivity rates for TPS (PD-L1), CPS (PD-L1), TPS (PD-L2), and CPS (PD-L2) were 73.8%, 78.2%, 56.4%, and 78.2%, respectively. Patients with high TPS (PD-L1), CPS (PD-L1), or CPS (PD-L1 and PD-L2) showed significantly prolonged progression-free survival. Favorable overall survival was associated with high CPS (PD-L1 and PD-L2) and low soluble PD-L1 and PD-L2 levels. The expressions of tissue and soluble PD-L1/2 were not correlated. Our study revealed that compared to PD-L1 expression alone, dual expression of PD-L1 and PD-L2 in tissue or soluble form could be feasible biomarkers in patients with RMHNSCC who received nivolumab.

CCAAT enhancer binding protein delta activates vesicle associated membrane protein 3 transcription to enhance chemoresistance and extracellular PD-L1 expression in triple-negative breast cancer

BackgroundChemoresistance and immunosuppression are two major obstacles in the current anti-cancer treatments. This study investigates the involvements of a CCAAT enhancer binding protein delta (CEBPD)/vesicle associated membrane protein 3 (VAMP3) axis in paclitaxel (PTX) resistance and immune evasion in triple-negative breast cancer (TNBC).MethodsPTX resistance-related genes were screened by bioinformatics. CEBPD and VAMP3 expression in clinical TNBC samples was examined by immunohistochemistry. Three PTX-resistant TNBC cell lines (MDA-MB-231/PTX, MDA-MB-468/PTX and MDA-MB-453/PTX) were generated, and their drug resistance was analyzed. Autophagy of cells was analyzed by immunofluorescence staining. Interaction between CEBPD and VAMP3 promoter was identified by immunoprecipitation and luciferase assays. The extracellular expression of programmed cell death-ligand 1 (PD-L1) in TNBC cells was detected. Extracellular vesicles (EVs) from TNBC cells were isolated to examine their effects on CD8+ T cell exhaustion.ResultsCEBPD and VAMP3 were upregulated in chemo-resistant tissue samples and in PTX-resistant TNBC cells. The CEBPD downregulation enhanced PTX sensitivity of cells. However, further upregulation of VAMP3 in cells restored PTX resistance, which was likely due to the activation of autophagy, as the autophagy antagonist chloroquine enhanced PTX sensitivity of cells. CEBPD was found to bind to the VAMP3 promoter to activate its transcription. The CEBPD/VAMP3 axis also increased the PD-L1 expression in the conditioned medium of TNBC cells. The TNBC cell-derived EVs increased the exhaustion of co-cultured CD8+ T cells.ConclusionThis study provides novel evidence that CEBPD plays a key role in enhancing PTX resistance in TNBC cells across various subtypes through VAMP3-mediated autophagy activation. Additionally, the CEBPD/VAMP3 axis also increases extracellular PD-L1 level, delivered by cancer cell-derived EVs, to suppress CD8+ T cell-mediated anti-tumor immune response. These significant observations may provide new insights into the treatment of TNBC, suggesting CEBPD and VAMP3 as promising targets to overcome treatment resistance.

Reducing PD-L1 Expression by Degraders and Downregulators as a Novel Strategy to Target the PD-1/PD-L1 Pathway.

Targeting the programmed cell death protein-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) pathway has evolved into one of the most promising strategies for tumor immunotherapy. Thus far, multiple monoclonal antibody drugs have been approved for treating a variety of tumors, while the development of small-molecule PD-1/PD-L1 inhibitors has lagged far behind, with only a few small-molecule inhibitors entering clinical trials. In addition to antibody drugs and small-molecule inhibitors, reducing the expression levels of PD-L1 has attracted extensive research interest as another promising strategy to target the PD-1/PD-L1 pathway. Herein, we analyze the structures and mechanisms of molecules that reduce PD-L1 expression and classify them as degraders and downregulators according to whether they directly bind to PD-L1. Moreover, we discuss the potential prospects for developing PD-L1-targeting drugs based on these molecules. It is hoped that this perspective will provide profound insights into the discovery of potent antitumor immunity drugs.

A real-world retrospective, observational study of first-line pembrolizumab plus chemotherapy for metastatic non-squamous non-small cell lung cancer with PD-L1 tumor proportion score < 50% (PEMBROREAL).

The phase III Keynote-189 trial established a first-line treatment combining pembrolizumab with pemetrexed and platinum as a standard treatment for patients with stage IV non-small cell lung cancer (NSCLC) without known EGFR and ALK driver mutations and independent of programmed cell death ligand 1 (PD-L1) expression. However, in Italy, eligibility for the National Health Service payment program is limited to patients with PD-L1 <50%. The PEMBROREAL study assesses the real-world effectiveness and safety of pembrolizumab in patients eligible for the National Health Service payment program. PEMBROREAL is a retrospective, observational study on patients with NSCLC who started pembrolizumab combined with pemetrexed and platinum within the reimbursability time window, considered as December 2019 to December 2020. The primary endpoints were to assess progression-free survival (PFS) and overall survival (OS; using the Kaplan-Meier method), response to therapy, and tolerability. Until February 2022, 279 patients (median follow-up: 19.7 months) have been observed. The median PFS was 8.0 months (95% confidence interval: 6.5-9.2). OS was not reached, but we can estimate a 12- to 24-month survival rate for the combined treatment: 66.1% and 52.5%, respectively. PD-L1 expression and Eastern Cooperative Group (ECOG) Performance Status were both associated with PFS and OS. Overall, only 44.4% of patients reported an adverse event, whereas toxicity led to a 5.4% discontinuation rate. The results of the PEMBROREAL study have shown that the combined treatment of pembrolizumab with pemetrexed and platinum is effective for metastatic non-squamous NSCLC, even for patients with PD-L1 levels below 50%, despite the differences in patient demographics and pathological features compared to the Keynote-189 study. The adverse events reported during the study were more typical of chemotherapy treatment rather than immunotherapy, and physicians were able to manage them easily.

Camptothecin enhances the anti-tumor effect of low-dose apatinib combined with PD-1 inhibitor on hepatocellular carcinoma

Apatinib has been shown to apply to a variety of solid tumors, including advanced hepatocellular carcinoma. Preclinical and preliminary clinical results confirmed the synergistic antitumor effects of apatinib in combination with anti-programmed death-1 (PD-1) inhibitors. In this study, we investigated camptothecin (CPT) enhances the anti-tumor effect of low-dose apatinib combined with PD-1 inhibitor on hepatocellular carcinoma. CPT combined with a PD-1 inhibitor enhances the anti-tumor effects of low-dose apatinib in hepatocellular carcinoma which was evaluated in making use of the H22 mouse model (n = 32), which was divided into four groups. Immunohistochemical staining and western blotting were used to detect nuclear factor erythroid 2-related factor 2 (Nrf2) as well as sequestosome 1 (p62), vascular endothelial growth factor A (VEGFA), vascular endothelial growth factor receptor 2 (VEGFR2), PD-1, and programmed cell death ligand 1 (PD-L1). The results showed that the average size of the tumor of the combination group (Group D) was significantly less than that of the apatinib + PD-1 inhibitor group (Group C). The expression levels of Nrf2, p62, VEGFA, VEGFR2, PD-1, and PD-L1 in the apatinib + PD-1 inhibitor group(Group C) were lower than those in the control group (Group A) (P < 0.05). The expression levels of these genes in the apatinib + PD-1 inhibitor group (Group C) were significantly lower in the combination group (Group D) (P < 0.05). There was no obvious difference in body weight and liver and kidney functions between the four groups of mice. In conclusion, CPT improves the anti-tumor effect of low-dose apatinib combined with PD-1 inhibitor on hepatocellular carcinoma

Application of Aptamer-SERS Nanotags for Unveiling the PD-L1 Immunomarker Progression Correlated to the Cell Metabolic Bioprocess.

In recent years, the expression and progression of programmed cell death ligand 1 (PD-L1) as an immunomarker in the context of a cell metabolic environment has gained significant attention in cancer research. However, intercellular bioprocesses that control the dynamics of PD-L1 have been largely unexplored. This study aimed to explore the cell metabolic states and conditions that govern dynamic variations of PD-L1 within the cell metabolic environment using an aptamer-based surface-enhanced Raman scattering (SERS) approach. The aptamer-SERS technique offers a sensitive, rapid, and powerful analytical tool for targeted and nondestructive detection of an immunomarker with high sensitivity and specificity. By combining aptamer-SERS with cell state profiling, we investigated the modulation in PD-L1 expression under different metabolic states, including glucose deprivation, metabolic coenzyme activity, and altered time/concentration-based cytokine availability. The most intriguing features in our findings include the cell-specific responses, cell differentiation by revealing distinct patterns, and dynamics of PD-L1 in different cell lines. Additionally, the time-dependent variations in PD-L1 expression, coupled with the dose-dependent relationship between glucose concentration and PD-L1 levels, underscore the complex interplay between immune checkpoint regulation and cellular metabolism. Therefore, this work demonstrates the advantages of using highly-sensitive and specific aptamer-SERS nanotags for investigating the immune checkpoint dynamics and related metabolic bioprocess.

PD-L1 on large extracellular vesicles is a predictive biomarker for therapy response in tissue PD-L1-low and -negative patients with non-small cell lung cancer.

Immunotherapy has revolutionized the treatment of patients with non-small cell lung cancer (NSCLC). High expression of tissue PD-L1 (tPD-L1) is currently the only approved biomarker for predicting treatment response. However, even tPD-L1 low (1-49%) and absent (<1%) patients might benefit from immunotherapy but, to date, there is no reliable biomarker, that can predict response in this particular patient subgroup. This study aimed to test whether tumour-associated extracellular vesicles (EVs) could fill this gap. Using NSCLC cell lines, we identified a panel of tumour-related antigens that were enriched on large EVs (lEVs) compared to smaller EVs. The levels of lEVs carrying these antigens were significantly elevated in plasma of NSCLC patients (n=108) and discriminated them from controls (n=77). Among the tested antigens, we focused on programmed cell death ligand 1 (PD-L1), which is a well-known direct target for immunotherapy. In plasma lEVs, PD-L1 was mainly found on a population of CD45- /CD62P+ lEVs and thus seemed to be associated with platelet-derived vesicles. Patients with high baseline levels of PD-L1+ lEVs in blood showed a significantly better response to immunotherapy and prolonged survival. This was particularly true in the subgroup of NSCLC patients with low or absent tPD-L1 expression, thus identifying PD-L1-positive lEVs in plasma as a novel predictive and prognostic marker for immunotherapy.

Expression of PD-L1 and p-RPS6 in epithelial dysplasia and squamous cell carcinoma of the oral cavity.

Oral squamous cell carcinoma (OSCC) is often preceded by oral epithelial dysplasia (OED). The role of ribosomal protein S6 (RPS6) and programmed cell death ligand-1 (PD-L1) in the progression of OED to OSCC remains unclear. This study aimed to investigate the expression of phosphorylated RPS6 (p-RPS6) and PD-L1 in OSCC and OED and to examine its relationship with clinicopathological features. Fifty-two OSCC and 48 OED cases were recruited for immunohistochemical analysis of p-RPS6 and PD-L1 expression. The expression of markers was correlated with clinicopathological features of OSCC and OED. We found p-RPS6 expression in all cases of OSCC and OED, whereas PD-L1 was expressed in 42/48 (87%) OED and in 28/52 (53%) OSCC. The patients with mild OED presented higher expression level of PD-L1 and p-RPS6 significantly, when compared to moderate-differentiated OSCC patients (p < 0.05). Moreover, we found a significant positive correlation between PD-L1 and p-RPS6 expression in OED and OSCC patients (p < 0.01). The PD-L1 expression was significantly related to more than 2 cm tumor size in OSCC patients (p = 0.007). Our findings suggest the upregulation of PD-L1 may be related with activation of the mTOR pathway in the early events of tumor progression and the pathogenesis of OSCC.

Epidermolysis-Bullosa-Associated Squamous Cell Carcinomas Support an Immunosuppressive Tumor Microenvironment: Prospects for Immunotherapy.

Cutaneous squamous cell carcinomas (SCCs) are a major complication of some subtypes of epidermolysis bullosa (EB), with high morbidity and mortality rates and unmet therapeutic needs. The high rate of endogenous mutations and the fibrotic stroma are considered to contribute to the pathogenesis. Patients with dystrophic EB (DEB) and Kindler EB (KEB) have the highest propensity for developing SCCs. Another patient group that develops high-risk SCCs is immunosuppressed (IS) patients, especially after organ transplantation. Herein, we interrogate whether immune checkpoint proteins and immunosuppressive enzymes are dysregulated in EB-associated SCCs as an immune resistance mechanism and compare the expression patterns with those in SCCs from IS patients, who frequently develop high-risk tumors and sporadic SCCs, and immunocompetent (IC) individuals. The expression of indoleamine 2,3-dioxygenase (IDO), programmed cell death protein-1 (PD-1), programmed cell death ligand-1 (PD-L1), T cell immunoglobulin and mucin-domain-containing protein-3 (TIM-3), lymphocyte activation gene-3 (LAG-3), and inflammatory infiltrates (CD4, CD8, and CD68) was assessed via immunohistochemistry and semi-quantitative analysis in 30 DEB-SCCs, 22 KEB-SCCs, 106 IS-SCCs, and 100 sporadic IC-SCCs. DEB-SCCs expressed significantly higher levels of IDO and PD-L1 in tumor cells and PD-1 in the tumor microenvironment (TME) compared with SCCs from IC and IS individuals. The number of CD4-positive T cells per mm2 was significantly lower in DEB-SCCs compared with IC-SCCs. KEB-SCCs showed the lowest expression of the exhaustion markers TIM-3 and LAG-3 compared with all other groups. These findings identify IDO, PD-1, and PD-L1 to be increased in EB-SCCs and candidate targets for combinatory treatments, especially in DEB-SCCs.

The prognostic significance of PD-1 and its ligands in non-small cell lung cancer.

In this study, we aimed to investigate the prognostic value of programmed cell death protein 1 (PD-1), programmed cell death ligand 1 (PD-L1), and programmed cell death ligand 2 (PD-L2) expressions on immune and cancer cells in terms of survival in patients with lung adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Between January 2000 and December 2012, a total of 191 patients (172 males, 19 females; mean age: 60.3±8.4 years; range, 38 to 78 years) who were diagnosed with non-small cell lung cancer and underwent anatomic resection and mediastinal lymph node dissection were retrospectively analyzed. The patients were evaluated in three groups including lung squamous cell carcinoma (n=61), adenocarcinoma (n=66), and large-cell carcinoma (n=64). The survival rates of all three groups were compared in terms of immunohistochemical expression levels of PD-1, PD-L1, and PD-L2. The mean follow-up was 71.8±47.9 months. In all histological subtypes, PD-1 expressions on tumor and immune cells were observed in 33% (61/191) and in 53.1% (102/191) of the patients, respectively. Higher expression levels of PD-L1 and PD-L2 at any intensity on tumor and immune cells were defined only in lung adenocarcinomas, and PD-L1 and PD-L2 values were detected in 36.4% (22/64) of these patients. The PD-L1 expressions on tumor and immune cells were observed in 41.7% (10/24) and 25% (6/24) of the patients, respectively. The PD-L2 expressions on tumor and immune cells were detected in 16.7% (4/24) and 8.4% (2/24) of the patients, respectively. Univariate and multivariate analyses revealed that PD-1 expression in tumor cells was an independent prognostic factor in all histological subtypes. Our study results suggest that PD-1 expression is a poor prognostic factor for overall survival in patients with completely resected adenocarcinoma, squamous cell carcinoma, and large cell carcinoma.

STAT4 facilitates PD-L1 level via IL-12R/JAK2/STAT3 axis and predicts immunotherapy response in breast cancer.

Signal transducer and activator of transcription 4 (STAT4) is a critical transcription factor for T helper cell differentiation and tumor cells. Although its prognostic role and gene function have been reported in several carcinomas, the role of STAT4 in vitro and in vivo in breast cancer remains poorly understood. The effect of STAT4 in immunotherapy is also unclear. Therefore, we integrated bulk transcriptomics, experiments, and single-cell transcriptomics to systematically analyze its function in prognosis and signaling pathway. Several clinical breast cancer cohorts confirmed STAT4 as a T-cell relevant prognostic biomarker. Overexpressed STAT4 increased programmed cell death ligand 1 (PD-L1) and major histocompatibility complex class II levels in breast cancer cells. In molecular mechanism, transcriptional synergy between STAT4 and STAT3 transactivated interleukin (IL)-12R and involved a positive feedback loop: STAT4/IL-12R/JAK2-STAT3-STAT4, which contributed to the upregulation of PD-L1 expression. The above signaling axis was defined as the STAT4-related pathway and its score was used to predict T-cell expansion and anti-PD1 treatment response. These findings highlight a novel molecular mechanism indirectly regulating PD-L1 through the STAT4-related pathway: IL-12R/JAK2-STAT3-STAT4/PD-L1, and it has potential application in predicting anti-PD-1 immunotherapy response, which may pave the way for stratified immunotherapy in breast cancer.

Expression of the immune checkpoint molecules PD‑L1 and PD‑1 in EBV‑associated lymphoproliferative disorders: A meta‑analysis.

Epstein-Barr virus (EBV) has been implicated in the development of a wide range of lymphoproliferative disorders. In this process, the role of programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) has remained to be clarified. A meta-analysis of 20 studies was performed and risk ratios (RRs) with 95% confidence intervals (CIs) were used to evaluate the association between PD-L1/PD-1 expression and the status of EBV infection. The results showed that the expression level of PD-L1 in tumor cells was significantly higher in EBV+ cases with a pooled RR of 2.26 (95% CI, 1.63-3.14; P<0.01), particularly in subtypes of diffuse large B-cell lymphoma (DLBCL) and classical Hodgkin lymphoma. Similarly, EBV infection increased the expression of PD-L1 in immune cells with a pooled RR of 2.20 (95% CI, 1.55-3.12; P<0.01). In subtypes of DLBCL and post-transplant lymphoproliferative disorder, the expression of PD-L1 in immune cells is increased in EBV+ cases. Regarding the expression level of PD-1 in tumor-infiltrating lymphocytes (TILs), no significance was found between EBV infection and PD-1 expression, with a pooled RR of 1.10 (95% CI, 0.81-1.48; P>0.05). The present meta-analysis demonstrated that in EBV-associated lymphoproliferative disorders, EBV infection was associated with the expression level of PD-L1 in tumor cells and immune cells but was not associated with the expression of PD-1 in TILs.