Tumor Programmed Cell Death Ligand 1 Research Articles

Platelets up-Regulate Tumor Cell Programmed Death-Ligand 1 through Epidermal Growth Factor Receptor Signal Transduction

Introduction: Programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) are important immune checkpoint proteins in cancer immunotherapy and targeted therapies against PD-L1 have significantly prolonged many patients' lives. Recently, high baseline platelet to lymphocyte ratio was reported to be associated with decreased patient response rate to immune checkpoint inhibition (ICI) therapies, including anti-PD-L1 therapy, suggesting the potential role of platelets in tumor immunity. Platelets express PD-L1 on their surface, and platelets binding to PD-L1 negative tumor cells can “decorate” tumor cells with PD-L1 and protect against T cell-mediated cytotoxicity. However, whether platelet can affect PD-L1 expression on tumor cells is still unknown.Methods: In this study, we designed platelet-tumor cell co-culture systems to investigate whether direct or indirect exposure to platelets affects tumor cell PD-L1 surface expression. Considering platelets can be artificially activated by commonly used cell culture medium, the co-culture was performed in platelet resuspension buffer (HEPES, NaCl, KCl, MgCl2, NaHCO3, Glucose, pH7.4) supplied with fetal bovine serum and L-glutamine. After 24 hours of co-culture, platelets were washed out and fresh culturing medium was added to tumor cells and cultured for another 24 hours. At the end of the experiments, tumor cells were harvested and the PD-L1 expression analyzed by flow cytometry and RT-qPCR.Results and discussion: Here we report that direct co-culture of platelets with either breast cancer cell line MDA-MB-468 or lung cancer cell line A549 increased tumor cell PD-L1 surface expression by up-regulating PD-L1 transcription. This platelet-induced tumor cell PD-L1 up-regulation can be partly reduced by pre-treating platelets with antiplatelet agents such as aspirin and ticagrelor, suggesting platelet activation contributes to platelet induced tumor cell PD-L1 up-regulation. The up-regulation of tumor cell PD-L1 by platelets was not due to abundant platelet cytokines such as C-C Motif Chemokine Ligand 5 (CCL5) and C-X-C motif chemokine 5 (CXCL5). However, both an epidermal growth factor (EGF) neutralizing antibody and cetuximab (EGFR neutralizing monoclonal antibody) decreased the platelet-induced increase in tumor cell PD-L1, suggesting that platelets initiate tumor cell PD-L1 transcription through the EGF signaling pathway. Our data indicate a novel function of platelets in tumor immunity and warrant further investigation to determine if targeting platelets offers a novel adjuvant approach to improve ICI therapy. DisclosuresItaliano: Sierra Oncology: Consultancy; PlateletBio: Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees; Carrick Therapeutics: Consultancy.

Efficacy and Safety of Programmed Cell Death 1 Inhibitor Monotherapy Versus Chemotherapy as Second-Line Treatment for Advanced Esophageal Cancer: A Meta-analysis and Systematic Review

PurposeWith programmed cell death 1 (PD-1) inhibitors approved for second-line treatment of advanced esophageal cancer, immunotherapy and chemotherapy have gradually become the main treatments for second-line treatment of patients with advanced esophageal cancer (AEC). This meta-analysis and systematic review were conducted to evaluate the efficacy and safety of PD-1 inhibitors monotherapy versus chemotherapy in second-line treatment of AEC. MethodsEligible randomized controlled trials were searched in PubMed, Embase, and the Cochrane Library and abstracts presented at the American Society of Clinical Oncology or European Society of Medical Oncology were reviewed to assess the efficacy and tolerability of PD-1/programmed cell death ligand 1 (PD-L1) inhibitors relative to chemotherapy for AEC from January 2016 to October 2020. Patients diagnosed with AEC and progressing after first-line therapy were included in this study. Hazard ratios (HRs) of progression-free survival (PFS) and overall survival (OS), risk ratios (RRs) of objective response rate (ORR), and the odds ratios (ORs) of adverse effects (AEs) were calculated. FindingsThe study included 4 randomized controlled trials with 1683 patients. The results indicated that PD-1 inhibitors prolonged the OS (HR = 0.79; 95% CI, 0.71–0.88; P < 0.01) and improved the ORR (RR = 3.00; 95% CI, 2.36–3.82; P = 0.01) but did not improve the PFS (HR = 0.96; 95% CI, 0.76–1.20; P = 0.692) compared with chemotherapy in the second-line treatment of AEC. PD-1 inhibitors alone were associated with a lower incidence of all treatment-related AEs (OR = 0.29; 95% CI, 0.09–0.89; P = 0.03) and grade 3 to 5 treatment-related AEs (OR = 0.26; 95% CI, 0.16–0.44; P < 0.01) versus chemotherapy. PD-1 inhibitors prolonged OS mainly in the following patient groups: male, age <65 years, Eastern Cooperative Oncology Group performance status of 1, or PD-L1 tumor proportion score ≥10%. Asian patients had a longer OS than non-Asian patients (P = 0.01). ImplicationsThe available evidence indicates that the efficacy and tolerability of PD-1 inhibitors were better than chemotherapy in the second-line treatment of AEC, and the benefiting population of these patients was limited to males, those <65 years of age, those with a Eastern Cooperative Oncology Group performance status of 1, or those with a PD-L1 tumor proportion score ≥10%. Notably, Asian patients receiving immune monotherapy had longer OS than non-Asian patients.

Expression of PD-L1 and BRCA1 in Triple-Negative Breast Cancer Patients and Relationship with Clinicopathological Characteristics.

Objective To study the expression of programmed cell death ligand-1 (PD-L1) and breast cancer susceptibility gene 1 (BRCA1) in triple-negative breast cancer (TNBC) patients and analyze their relationship with clinicopathological characteristics. Methods 76 TNBC tissues were collected as the research object, while 60 adjacent tissues were used as controls. All patients underwent surgical treatment, and the expression of PD-L1 and BRCA1 in cancer tissues and adjacent tissues was detected by immunohistochemistry. At the same time, the relationship between PD-L1, BRCA1, and clinicopathological characteristics of patients with TNBC (including patient age, menopausal status, tumor size, lymph node metastasis, histological grade, Ki-67 expression, and p53 expression) were analyzed by univariate and logistic multivariate analysis. Results The positive expression rate of PD-L1 in the TNBC group was 64.47%, which was higher than the control group by 41.67%. The positive expression rate of BRCA1 was 27.63%, which was lower than the control group by 48.33%. PD-L1 expression has no significant relationship with age, menopausal status, and p53 expression in TNBC patients. TNBC patients with tumors ≥2 cm, histological grade III, lymph node metastasis, and Ki-67 expression ≥20% had higher PD-L1 positive expression rates. The tumor size, Ki-67 expression, and PD-L1 expression of TNBC patients have independent effects. The expression of BRCA1 has no significant relationship with menopausal status, tumor size, Ki-67 expression, etc. TNBC patients with age <45 years, histological grade I or II, no lymph node metastasis, and high p53 expression positive rate had higher BRCA1 positive expression rate. The age of TNBC patients, p53 expression, and BRCA1 expression have independent effects. Conclusion In TNBC cancer tissues, there is a high expression of PD-L1 and low expression of BRAC1. The tumor size, Ki-67 expression, and PD-L1 expression of TNBC patients have independent effects. The age of TNBC patients, p53 expression, and BRCA1 expression have independent effects.

PD-L1 (SP142) testing is concordant between Benchmark Ultra and Bond-III stainers

BackgroundAtezolizumab is an inhibitor of programmed death-ligand 1 (PD-L1), used to treat advanced or metastatic bladder cancer, and in trials for non-invasive disease. In order to be eligible for treatment, patients require a PD-L1 immune cell score ≥ 5%, using the Ventana SP142 PD-L1 assay. Many laboratories do not have access to the required Ventana Benchmark Ultra stainer, and it is unclear if the assay performs similarly on other stainers. In this study, we compare SP142 assay results between Ventana Benchmark Ultra and Leica Bond-III stainers.MethodsSerial sections of 90 samples of transurethral bladder resections (comprising 51 pTaHG, 8 pTis, 18 pT1, 10 pT2 tumors) were stained using the SP142 PD-L1 antibody on Ventana Benchmark Ultra and Leica Bond-III stainers, manually scored, and compared using accuracy and Cohen’s kappa measures.ResultsBoth devices yielded highly concordant PD-L1 immune cell scores (accuracy 0.84, Cohen’s κ 0.732). Moreover, we found similar tumor cell (TC) PD-L1 scores using both stainers, and a trend towards greater TC scores in pT2 stage samples (p = 0.05).ConclusionThis study is the first to compare the SP142 antibody in bladder cancer on two different stainers. Our results indicate that both Benchmark Ultra and Bond-III stainers yield highly concordant results using the SP142 PD-L1 antibody.

The Role of Oncogenes and Redox Signaling in the Regulation of PD-L1 in Cancer.

Simple SummaryPD-L1 is an important immune checkpoint molecule that is expressed in cancer tissues at various levels and plays a major role in tumor evasion from immune system. Therefore, understanding the mechanisms by which PD-L1 expression is regulated in tumor environment is important for the design of new therapeutic strategies to overcome tumor immune escape and improve the outcome of cancer treatment. Recent studies suggest that genetic, epigenetic, and transcriptional factors as well as posttranscriptional and posttranslational processes are crucial regulators of PD-L1 expression in tumor cells. This review focuses on two newly described regulations of PD-L1 mediated by oncogenes, and redox homeostasis. In this context, a recent research work describes the important role of oncogenic K-ras, growth factor receptors (FGFR1 and EGFR) and ROS in regulating PD-L1 expression in pancreatic cancer cells and aids significant new mechanistic insights in this important area.Tumor cells can evade the immune system via multiple mechanisms, including the dysregulation of the immune checkpoint signaling. These signaling molecules are important factors that can either stimulate or inhibit tumor immune response. Under normal physiological conditions, the interaction between programmed cell death ligand 1 (PD-L1) and its receptor, programmed cell death 1 (PD-1), negatively regulates T cell function. In cancer cells, high expression of PD-L1 plays a key role in cancer evasion of the immune surveillance and seems to be correlated with clinical response to immunotherapy. As such, it is important to understand various mechanisms by which PD-L1 is regulated. In this review article, we provide an up-to-date review of the different mechanisms that regulate PD-L1 expression in cancer. We will focus on the roles of oncogenic signals (c-Myc, EML4-ALK, K-ras and p53 mutants), growth factor receptors (EGFR and FGFR), and redox signaling in the regulation of PD-L1 expression and discuss their clinical relevance and therapeutic implications. These oncogenic signalings have common and distinct regulatory mechanisms and can also cooperatively control tumor PD-L1 expression. Finally, strategies to target PD-L1 expression in tumor microenvironment including combination therapies will be also discussed.

Genetic alternations and immune characteristics in patients with small cell lung cancer

Genetic alternations and immune characteristics in patients with small cell lung cancer

Promising potential of a 18F-labelled small-molecular radiotracer to evaluate PD-L1 expression in tumors by PET imaging

Programmed death ligand 1 (PD-L1) expression level is a reproducible biomarker for guiding stratification of patients to immunotherapy. However, the most widely used immunohistochemistry method is incompetent to fully understand the PD-L1 expression level in the whole body because of the highly complex PD-L1 expression in the tumor microenvironment. In this work, a novel small-molecular radiotracer [18F]LG-1 based on the biphenyl active structure was developed to evaluate PD-L1 expression in tumors. [18F]LG-1 was obtained by conjugating and radiolabeling with [18F]FDG with high radiochemical purity (>98.0%) and high molar activity (37.2 ± 2.9 MBq/nmol). In vitro experimental results showed that [18F]LG-1 could target PD-L1 in tumor cells and the cellular uptake in A375-hPD-L1 cells (PD-L1 + ) was clearly higher than that in A375 cells (PD-L1-). In vivo dynamic PET images of [18F]LG-1 provided clear visualization of A375-hPD-L1 tumor with high tumor-to-background contrast, and the tumor uptake was determined to be 3.98 ± 0.21 %ID/g at 60 min, which was 2.6-fold higher than that of A375 tumor. These results suggested that [18F]LG-1 had great potential as a promising PD-L1 radiotracer.

A retrospective analysis of eleven gene mutations, PD-L1 expression and clinicopathological characteristics in non-small cell lung cancer patients

ObjectivesTo investigate the associations among expression of programmed cell death ligand 1 (PD-L1), eleven mutated genes, and clinicopathological characteristics in 273 patients with non-small cell lung cancer (NSCLC). MethodsWe retrospectively examined tumor PD-L1 expression in 247 surgically resected primary and 26 advanced NSCLC patients by immunohistochemistry using SP263 antibody assay. Gene mutations of EGFR, TP53, KRAS, PIK3CA, ERBB2, MET, RET, ALK, BRAF, ROS1, and APC were examined by NGS sequence. Data analysis was carried out using SPSS 22.0. The associations among PD-L1 expression, eleven mutated genes and clinicopathological characteristics were assessed by univariate and multivariate analysis. ResultsAmong the total 273 patients, 68 (24.9%) patients were positive for PD-L1 expression. Data showed that mutated rate of EGFR gene was the highest with 63.0% (172/273), followed by TP53 (11.7%, 32/273) and KRAS (5.5%, 15/273). The female, non-smoker, and patients with adenocarcinoma (ADC) were more likely to have EGFR mutations. Multivariate logistic regression showed that PD-L1 expression was significantly associated with Non-ADC, lymphatic invasion, EGFR wild type and TP53 mutation (p = 0.041, <0.001, 0.004 and 0.014, respectively). Moreover, PD-L1 expression in adenocarcinoma was associated with lymphatic invasion, mutation of TP53 and KRAS gene (p = 0.012, <0.025 and 0.041, respectively). ConclusionsMutations of EGFR, KRAS and TP53 should be routinely detected in clinical practice to better guide the immunotherapy for NSCLC patients. Future investigations are warranted to illustrate the potential mechanisms between driver mutations and PD-L1 expression for guiding immunotherapy in patients with NSCLC.

M6A Demethylase ALKBH5 Regulates PD-L1 Expression and Tumor Immunoenvironment in Intrahepatic Cholangiocarcinoma.

N6-methyladenosine (m6A) has been reported as an important mechanism of posttranscriptional regulation. Programmed death-ligand 1 (PD-L1) is a primary immune inhibitory molecule expressed on tumor cells that promotes immune evasion. Here we report ALKBH5 as an important m6A demethylase that orchestrates PD-L1 expression in intrahepatic cholangiocarcinoma (ICC). Regulation of PD-L1 expression by ALKBH5 was confirmed in human ICC cell lines. Sequencing of the m6A methylome identified PD-L1 mRNA as a direct target of m6A modification whose levels were regulated by ALKBH5. Furthermore, ALKBH5 and PD-L1 mRNA were shown to interact. ALKBH5 deficiency enriched m6A modification in the 3'UTR region of PD-L1 mRNA, thereby promoting its degradation in a YTHDF2-dependent manner. In vitro and in vivo, tumor-intrinsic ALKBH5 inhibited the expansion and cytotoxicity of T cells by sustaining tumor cell PD-L1 expression. The ALKBH5-PD-L1-regulating axis was further confirmed in human ICC specimens. Single-cell mass cytometry analysis unveiled a complex role of ALKBH5 in the tumor immune microenvironment by promoting the expression of PD-L1 on monocytes/macrophages and decreasing the infiltration of myeloid-derived suppressor-like cells. Analysis of specimens from patients receiving anti-PD1 immunotherapy suggested that tumors with strong nuclear expression patterns of ALKBH5 are more sensitive to anti-PD1 immunotherapy. Collectively, these results describe a new regulatory mechanism of PD-L1 by mRNA epigenetic modification by ALKBH5 and the potential role of ALKBH5 in immunotherapy response, which might provide insights for cancer immunotherapies. SIGNIFICANCE: This study identifies PD-L1 mRNA as a target of ALKBH5 and reveals a role for ALKBH5 in regulating the tumor immune microenvironment and immunotherapy efficacy.

PD-L1 targeting and subclonal immune escape mediated by PD-L1 mutations in metastatic colorectal cancer

BackgroundIn patients with microsatellite stable (MSS) metastatic colorectal cancer (mCRC), immune checkpoint blockade is ineffective, and combinatorial approaches enhancing immunogenicity need exploration.MethodsWe treated 43 patients with predominantly microsatellite stable RAS/BRAF...

Programmed Death Ligand 1 (PD-L1) Expression and its Association with Clinicopathologic Profile in Patients with Non-Small Cell Lung Cancer in a Philippine Tertiary Medical Center

Introduction. The current management of advanced non-small cell lung cancer (NSCLC) includes the characterization of Programmed Death Ligand-1 (PD-L1) expression for potential immune checkpoint inhibitor treatment. There is currently no available data regarding the patterns of PD-L1 expression in NSCLC, as well as their association with clinicopathologic profile in Filipino patients. Methodology. Clinicopathologic characteristics of 187 consecutive NSCLC clinical samples with PD-L1 testing using the clone 22C3 pharmaDx kit were collected. The presence of stromal tumor-infiltrating lymphocytes (TILs) were assessed in hematoxylin and eosin-stained slides. PD-L1 expression on tumor cells (TC) and stromal TILs were evaluated. Results. Of the 187 cases, there were 112 males and 75 females. The mean age at diagnosis was 66.4 years old (32-92 years old). It is composed of 131 cases of Adenocarcinoma, 15 Squamous cell carcinoma, 4 Adenosquamous carcinoma, 32 Non-small cell carcinoma, not otherwise specified, 3 poorly differentiated malignancy, 1 Large cell carcinoma, and 1 Mucinous carcinoma. Specimen types included 17 pleural fluid cell blocks, 60 tumor cell block samples, and 110 tissue biopsies. Tumor cell PD-L1 expression was identified in 59.1% of the 110 tissue biopsies. PD-L1 TPS for histologic specimens are as follows: TPS >50%, TPS 1-49%, and TPS <1% were observed in 23.6%, 35.5%, and 40.9% in our lung cancer cohort, respectively. Of the 77 cytology specimens, 50.6% presented with TC PD-L1 expression. TPS for this subgroup include: 49.4% with no PD-L1 expression, 35.1% with low PD-L1 expression, and 15.6% showing high PD-L1 expression. PD-L1 expression on TC did not correlate with age, sex, or histology for both specimen type subgroups. Stromal tumor-infiltrating lymphocytes were noted in 74.5% of tissue biopsies. Tumor cell block samples did not demonstrate stromal TILs. For tissue biopsies, female gender and TPS 1-49% were more likely to have <50% PD-L1 expression on TILs. Conclusion. Overall TC PD-L1 expression was observed in more than half (55.6%) of NSCLC patients in our cohort. The prognostic value of PD-L1 and clinical response to immune checkpoint inhibitors in the Filipino population needs to be further investigated.

Platelet Programmed Cell Death Ligand 1 (pPDL-1) Is a Prognostic Marker in Advanced Lung Cancer

Introduction. PDL-1 (Programmed Cell Death Ligand-1) expressed on non small cell lung cancer (NSCLC) cells mediates immune escape, and inhibition of PDL-1/PD-1 interaction with blocking antiboides induces long-term responses in a subpopulation of patients with metastatic NSCLC. PDL-1 immunohistochemistry is a controversial means of predicting responders, and further biomarkers are urgently needed. Herein, we report on the phenomenon of PDL-1 expressed on the surface of platelets (platelet PDL-1, pPDL-1) in patients with advanced NSCLC.Methods. Blood samples were prospectively collected from patients, and platelet-expressed PDL-1 expression was measured by flow cytometry utilizing flow monoclonal antibodies clones MIH1 and 28-8. Correlations of pPDL-1 expression levels with histopathological data, laboratory data, and survival were analyzed.Results. 79 NSCLC patients (53 with adenocarcinoma and 26 with squamous cell carcinoma) and 42 healthy controls were analyzed. 61 patients (77.2%) had stage IV disease. Platelets derived from healthy controls expressed little if any pPDL-1. Mean pPDL-1 expression in tumor patients was significantly increased compared with controls. PPDL-1 was not correlated with histological subtypes, mutational status, smoking history, clinical stage or laboratory data. However, overall survival (OS) and progression free survival (PFS) were significantly reduced in patients with a high (above median) percentage of PDL-1-positive platelets as compared with low pPDL-1(OS: 29 vs. 45 months, p = 0.027, PFS: 6 vs. 9 months, p = 0.036). The accuracy of our system was validated by calculating the area under the receiver-operator characteristic (ROC) curve. Here, platelet-derived PDL-1 expression was also significantly associated with a reduced OS (AUC=0.719, 95 CI: 0.587- 0.851) and PFS (AUC=0.768, 95 CI: 0.59- 0.89).Conclusion. To our knowledge, this is the first report of PDL-1 expression on platelets. In NSCLC patients, high pPDL-1 - similar to tumor PDL-1 - is clearly prognostic. The functional significance and predictive value of pPDL-1 remains to be established. DisclosuresNo relevant conflicts of interest to declare.

Characterization of immune infiltration in sarcomatoid hepatocellular carcinoma.

Sarcomatoid hepatocellular carcinoma (sHCC) is a rare type of liver malignancy. Currently, the tumor immune features of sHCC are poorly understood. We recruited 31 patients with resected sHCC for whom tissue samples and complete clinicopathologic and follow-up data were available. To understand the immune infiltration of sHCC, immunohistochemical staining was performed on the resected sHCC samples to compare the expressions of programmed death-1 (PD-1), programmed death-ligand 1 (PD-L1), B7-H3, indoleamine 2,3-dioxygenase (IDO), lymphocyte-activation gene 3 (LAG-3), CD8, FOXP3, and CD68 in tumor and peritumoral tissues. Kaplan-Meier and Cox regression analyses were used to assess the predictive value of immune markers. Sarcomatoid components were characterized with significantly higher expression of PD-L1 and B7-H3 in tumor cells than in conventional HCC components, as well as in peritumoral tissue. Additionally, sarcomatoid components had a higher density of FOXP3+ and LAG-3+ cells and a lower density of CD8+ cells than conventional HCC components or peritumoral tissue. Higher expression of PD-L1 in tumor cells significantly correlated with higher densities of CD8+, PD-1+, and LAG-3+ cells. Increased tumor PD-L1 expression and decreased CD8+ T-cell density were associated with poor overall survival (OS) and disease-free survival (DFS) in patients of sHCC. These findings suggest further characterization on relative mechanism of sHCC immune infiltration may identify therapeutic targets for immunotherapy.

Expression of programmed death ligand 1 (PD-L1) in urothelial bladder carcinoma (immunohistochemical and histopathological study)

The aim of this work is to evaluate the immunohistochemical expression of PD-L1 in tumor cells of urothelial bladder carcinoma. PD-L1 immunoexpression was assessed on 20 cases of radical cystectomy specimens using monoclonal rabbit anti- PD-L1 antibody. Extent of membranous PD-L1 expression was assigned in each case. Tumor cells showing > 5% expression were considered positive. PD-L1was seen in 6 (30%) cases [1 case score +2 and 5 cases score +3], while 14(70%) cases were negative [7 cases score 0 and 7 cases score +1]. PD-L1 expression in tumor cells was insignificantly correlated with different available clinicopathological parameters such as sex, pathological stage, associatedbilharzial infestation, necrosis, perineural invasion and associated tumor infiltrating mononuclear cells (TIMCs), although PD-L1 positivity tend to predominate in advanced pathological stage of tumor (T3 and T4). These findings may have clinical implications for the management of patients with PD-L1 positive urothelial bladder carcinoma.

PD-L1 Expression and Tumor Infiltrating Lymphocytes in Neurofibromatosis Type 1-Related Benign Tumors and Malignant Peripheral Nerve Sheath Tumors: An Implication for Immune Checkpoint Inhibition Therapy

Neurofibromatosis type 1 (NF1) is an autosomal dominant inherited disorder. It can affect multiple systems of the body and cause severe disfigurement and discomfort in these patients. There are two types of neurofibromas, named cutaneous and plexiform neurofibromas. The latter type may transform into malignant peripheral nerve sheath tumors (MPNSTs). Surgical resection is difficult to perform owing to the complex tissue structure of neurofibromas; therefore, it is necessary to develop novel and effective therapies for the treatment of these tumors. Programmed cell death protein 1 (PD-1)/programmed cell death-ligand 1 (PD-L1)-related immune checkpoint inhibitors have been proven effective for various cancers, and the positive expression of PD-L1 and tumor-infiltrating lymphocytes (TILs) has been recognized as a biomarker for the response to immune checkpoint therapy. We conducted immunohistochemistry (IHC) staining to detect PD-L1 expression in plexiform neurofibroma and MPNST tissue samples. Reverse transcription-polymerase chain reaction (RT-PCR) and western blotting were performed to detect PD-L1 and PD-1 expression in MPNST cell lines. IHC staining was used to show immune cell infiltration in NF1 and MPNST tissues. IHC staining showed PD-L1 positive expression in neurofibromas and MPNST tumor tissues. In addition, qPCR and western blotting showed high expression of PD-L1 in MPNST tumor cells. IHC staining revealed that aberrant T lymphocytes infiltrated the plexiform neurofibroma and MPNST tumor tissues. These results indicate that immune checkpoint mechanisms may play a pivotal role in the development of NF1-related tumors, and immune checkpoint inhibitors may be effective for managing neurofibromas and MPNSTs. Combined therapy with other molecular agents may be explored in the future.

Impact of PD-L1 combined positive score (CPS) on clinical response to nivolumab in patients with advanced esophageal squamous cell carcinoma.

e16045 Background: The ATTRACTION-3 trial showed that nivolumab (Nivo) significantly improved overall survival (OS) of patients (pts) with previously treated advanced esophageal squamous cell carcinoma (ESCC) regardless of tumor programmed cell death ligand-1 (PD-L1) expression assessed with tumor proportion score (TPS). On the other hand, pembrolizumab prolonged OS in advanced esophageal carcinoma pts with combined positive score (CPS) of ≥ 10 in the KEYNOTE-181 trial. Whether CPS can predict clinical outcome of Nivo in advanced ESCC pts remains unclear. Methods: We retrospectively evaluated advanced ESCC pts who received Nivo at a single institution between January 2014 and September 2020. The main eligibility criteria were as follows: refractory or intolerant to fluoropyrimidines and platinum, no prior anti-PD-1/PD-L1 antibody treatment, no comorbid malignancies, and available tissue specimens obtained before initiation of Nivo. PD-L1 immunostaining was performed using PD-L1 IHC 22C3 pharmDx assay, and the tumors were classified into three groups depending on CPS (≥ 10, 1–10, &lt; 1). The adjusted hazard ratios (aHRs) for progression-free survival (PFS) and OS were calculated using a multivariate Cox model that contained variables with p values &lt; 0.05 in the univariate analysis. Results: Among 69 pts, 50 were eligible (CPS ≥ 10/CPS 1–10/CPS &lt; 1, 23/18/9). Patient characteristics were as follows (CPS ≥ 10/CPS 1–10/CPS &lt; 1): age, ≥ 65, 70/67/67%; male, 83/67/78%; PS ≥ 1, 61/72/44%; second-line treatment, 65/61/56%; disease status, recurrent, 61/33/78%; prior esophagectomy, 65/33/44%; prior radiotherapy, 57/56/56%; prior taxane, 52/28/44%; the number of metastatic sites, ≥ 2, 48/61/89%; lymph node metastasis, 78/83/89%, lung metastasis, 26/22/56%; liver metastasis, 17/17/44%. Among 42 pts (84%) with disease progression after Nivo treatment, 24 pts received salvage-line chemotherapy. The adjustment factor for PFS was liver metastasis, while that for OS was not detected. The median PFS was 4.1 months (mo) in CPS ≥ 10 and 2.5 mo in CPS 1–10 (HR vs. CPS ≥ 10, 1.06; 95% CI, 0.51–2.17; p = 0.864; aHR, 1.15; 95% CI, 0.54–2.36; p = 0.713), and 1.4 mo in CPS &lt; 1 (HR vs. CPS ≥ 10, 3,78; 95% CI, 1.53–8.92; p = 0.005; aHR, 1.91; 95% CI, 0.67–5.39; p = 0.223). The median OS was 12.3 mo in CPS ≥ 10, 10.2 mo in CPS 1–10 (HR vs. CPS ≥ 10, 1.72; 95% CI, 0.75–4.00; p = 0.201), and 9.0 mo in CPS &lt; 1 (HR vs. CPS ≥ 10, 2.31; 95% CI, 0.92–5.69; p = 0.075). Objective response rate (CPS ≥ 10/CPS 1–10/CPS &lt; 1) in 40 pts who had measurable lesions were 32/25/0%, respectively. Conclusions: The pts with CPS of &lt; 1 did not respond to Nivo. Our study suggests that CPS is useful for predicting response to Nivo in pts with advanced ESCC.[Table: see text]

Clinical performance of artificial intelligence-powered annotation of tumor cell PD-L1 expression for treatment of immune-checkpoint inhibitor (ICI) in advanced non-small cell lung cancer (NSCLC).

9026 Background: Programmed death ligand 1 (PD-L1) expression is the standard biomarker for first line ICI in advanced NSCLC. However, manual evaluation of tumor proportion score (TPS) by pathologists has practical limitations including intra/inter-observer bias, variation in subjectivity on area of interest and intensive labor. We developed an artificial intelligence (AI)-powered TPS analyzer, namely Lunit SCOPE PD-L1, for objective annotation of tumor cell PD-L1 expression for prediction of ICI response in advanced NSCLC. Methods: Lunit SCOPE PD-L1 was developed by a total of 393,565 tumor cells annotated by board-certified pathologists for PD-L1 expression in 802 whole-slide images (WSI) stained by 22C3 pharmDx immunohistochemistry. A After excluding the in-house control tissue regions, the WSI were divided into patches, from which a deep learning-based model detected the location and PD-L1 positivity of tumor cells. The patch-level cell predictions were aggregated for TPS estimation. Clinical performance of the model was validated in an external cohort of 430 NSCLC tumor slides from patients treated with ≥ ICI at Seoul National University Bundang Hospital and Samsung Medical Center. Independent control TPS annotation of this external validation cohort was performed by three pathologists, and their consensus TPS was calculated by mean value of such. Results: AI-model (Lunit SCOPE PD-L1) predicts PD-L1-positive tumor cell with the area under the curves of 0.889 and PD-L1-negative tumor cells with that of 0.809 at cell-level analysis. At WSI-level, significant positive correlation was observed between TPS by AI model and control TPS by pathologists (Spearman coefficient = 0.9247, P &lt; 0.001). Concordance rate between AI-model and control TPS by pathologists according to expression level of PD-L1 ≥ 50%, 1-49%, and &lt; 1% status was 85.7%, 89.3%, and 52.4%, respectively. Median progression-free survival (mPFS) according to TPS by AI model ≥ 1% vs. &lt; 1% were 2.8 vs. 1.7 months (hazard ratio, HR, 0.52, 95% confidence interval, CI, 0.38-0.71, P &lt; 0.001). In contrast, mPFS according to control TPS was 2.8 vs. 2.1 months (HR 0.70, 95% CI 0.55-0.91, P &lt; 0.001). Forty out of 84 patients (47.6%) annotated as control TPS &lt; 1% by pathologists were considered as TPS ≥ 1% by AI-model and mPFS of this subgroup was 2.7 months. Conclusions: PD-L1 expression by AI-model correlates with PD-L1 expression by pathologists. Clinical performance of AI-model in WSI-level is comparable with assessment by pathologists. The AI-model can accurately predict tumor response and progression-free survival of ICI in advanced NSCLC.

Integrated analysis of programmed cell death ligand 1 expression reveals increased levels in high-grade glioma

PurposeGliomas are the most frequent primary brain tumors of adults. Despite intensive research, there are still no targeted therapies available. Here, we performed an integrated analysis of glioma and programmed cell death ligand 1 (PD-L1) in 90 samples including 58 glioma and 32 control brain tissues.MethodsTo identify PD-L1 expression in glioma, we performed immunohistochemical analysis of PD-L1 tumor proportion score (TPS) using the clinically valid PD-L1 22C3 antibody on 90 samples including controls and WHO grade I–IV gliomas.ResultsWe found that PD-L1 is highly expressed in a subfraction of glioma cells. Analysis of PD-L1 levels in different glioma subtypes revealed a strong intertumoral variation of PD-L1 protein. Furthermore, we correlated PD-L1 expression with molecular glioma hallmarks such as MGMT-promoter methylation, IDH1/2 mutations, TERT promoter mutations and LOH1p/19q.ConclusionIn summary, we found that PD-L1 is highly expressed in a subfraction of glioma, indicating PD-L1 as a potential new marker in glioma assessment opening up novel therapeutic approaches.

Programmed death ligand-1 regulates angiogenesis and metastasis by participating in the c-JUN/VEGFR2 signaling axis in ovarian cancer.

BackgroundAlthough programmed cell death‐ligand 1 (PD‐L1) plays a well‐known function in immune checkpoint response by interacting with programmed cell death‐1 (PD‐1), the cell‐intrinsic role of PD‐L1 in tumors is still unclear. Here, we explored the molecular regulatory mechanism of PD‐L1 in the progression and metastasis of ovarian cancer.MethodsImmunohistochemistry of benign tissues and ovarian cancer samples was performed, followed by migration, invasion, and angiogenesis assays in PD‐L1‐knockdown ovarian cancer cells. Immunoprecipitation, mass spectrometry, and chromatin immunoprecipitation were conducted along with zebrafish and mouse experiments to explore the specific functions and mechanisms of PD‐L1 in ovarian cancer.ResultsOur results showed that PD‐L1 induced angiogenesis, which further promoted cell migration and invasion in vitro and in vivo of ovarian cancer. Mechanistically, PD‐L1 was identified to directly interact with vascular endothelial growth factor receptor‐2 (VEGFR2) and then activated the FAK/AKT pathway, which further induced angiogenesis and tumor progression, leading to poor prognosis of ovarian cancer patients. Meanwhile, PD‐L1 was found to be regulated by the oncogenic transcription factor c‐JUN at the transcriptional level, which enhanced the expression of PD‐L1 in ovarian cancer. Furthermore, we demonstrated that PD‐L1 inhibitor durvalumab, combined with the antiangiogenic drug, apatinib, could enhance the effect of anti‐angiogenesis and the inhibition of cell migration and invasion.ConclusionOur results demonstrated that PD‐L1 promoted the angiogenesis and metastasis of ovarian cancer by participating in the c‐JUN/VEGFR2 signaling axis, suggesting that the combination of PD‐L1 inhibitor and antiangiogenic drugs may be considered as a potential therapeutic approach for ovarian cancer patients.

Robust Prediction of Immune Checkpoint Inhibition Therapy for Non-Small Cell Lung Cancer.

BackgroundThe development of immune checkpoint inhibitors (ICIs) is a revolutionary milestone in the field of immune-oncology. However, the low response rate is the major problem of ICI treatment. The recent studies showed that response rate to single-agent programmed cell death protein 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) inhibition in unselected non-small cell lung cancer (NSCLC) patients is 25% so that researchers defined several biomarkers to predict the response of immunotherapy in ICIs treatment. Common biomarkers like tumor mutational burden (TMB) and PD-L1 expression have several limitations, such as low accuracy and inadequately validated cutoff value.MethodsTwo published and an unpublished ICIs treatment NSCLC cohorts with 129 patients were collected and divided into a training cohort (n = 53), a validation cohort (n = 22), and two independent test cohorts (n = 34 and n = 20). We identified six immune-related pathways whose mutational status was significantly associated with overall survival after ICIs treatment. Then these pathways mutational status combined with TMB, PD-L1 expression and intratumor heterogeneity were incorporated to build a Bayesian-regularization neural networks (BRNN) model to predict the ICIs treatment response.ResultsWe firstly proved that TMB, PD-L1, and mutant-allele tumor heterogeneity (MATH) were independent biomarkers. The survival analysis of six immune-related pathways revealed the mutational status could distinguish overall survival after ICIs treatment. When predicting immunotherapy efficacy, the overall accuracy of area under curve (AUC) in validation cohort reaches 0.85, outperforming previous predictors in either sensitivity or specificity. And the AUC in two independent test cohorts reach 0.74 and 0.80.ConclusionWe developed a pathway-model that could predict the efficacy of ICIs in NSCLC patients. Our study made a significant contribution to solving the low prediction accuracy of immunotherapy of single biomarker. With the accumulation of larger data sets, further studies are warranted to refine the predictive performance of the approach.