Programmed Death Ligand-1 Negative Tumors Research Articles

Assessment of PD-L1, TROP2, and nectin-4 expression in penile squamous cell carcinoma

ObjectivesThere is an unmet need for therapeutically relevant biomarkers for advanced penile squamous cell carcinoma (pSCC). Proposed immunohistochemistry (IHC)-based biomarkers include programmed death-ligand 1 (PD-L1), trophoblast cell-surface antigen 2 (TROP2), and nectin-4; however, there is a paucity of data pertaining to these biomarkers. Herein, we investigated the expression of PD-L1, TROP2, and nectin-4 in a well-annotated cohort of pSCCs. MethodsA single-institution pathology archive was queried for patients who had a partial or total penectomy for pSCC between January 2000 and December 2022. Whole-slide sections were stained with antibodies against PD-L1 (22C3), TROP2, and nectin-4. Expression in tumor cells was quantified using H-scores (0–300). Associations between IHC expression, human papilloma virus (HPV) status, clinicopathologic findings, and outcome parameters were evaluated. ResultsThis study included 121 patients. For PD-L1, the median combined positive and H-scores were 1 and 0, respectively; 32.7 % of the cases had an H-score>0. Compared to PD-L1–negative tumors, PD-L1–positive tumors had higher pT stage and grade. The median TROP2 and nectin-4 H-scores were 230 and 140, respectively, with high TROP2 and nectin-4, defined by an H-score>200, noted in 80.7 % and 10.9 % of cases, respectively. High-risk HPV–positive cases had higher TROP2 and nectin-4 scores compared to HPV–negative cases. Patients with high TROP2 expression had significantly more disease progression, and patients with high nectin-4 expression had significantly fewer deaths due to disease. ConclusionsHigh expression of TROP2 and nectin-4 in pSCC support evaluation of these markers as therapeutic targets pending validation of our findings.

1145P Atezolizumab and stereotactic body radiotherapy in patients with advanced non-small cell lung cancer: The ComIT-1 trial

The emerging use of immune checkpoint inhibitors has transformed the treatment landscape of metastatic non-small cell lung cancer (NSCLC). However, challenges remain to increase the number of patients achieving durable clinical responses to these drugs, and to help monitor the treatment effect. In this phase II trial, we investigated the toxicity, systemic responses and circulating tumor DNA (ctDNA) responses in patients with advanced NSCLC treated with atezolizumab and stereotactic body radiotherapy (SBRT). Patients with metastatic NSCLC previously treated with a platinum doublet were included. SBRT (3 doses of 6 Gy) was given with concurrent atezolizumab 1200 mg every three weeks until no clinical benefit, intolerable toxicity, or a maximum of two years. Safety and clinical responses were registered. Plasma collected at baseline, during treatment and at progression was analyzed by next-generation sequencing using a 52-gene panel. We examined the relationship between longitudinal changes in ctDNA levels quantified using the allele frequency (AF) of lung cancer-associated somatic mutations, and radiographic responses for each patient. 21 patients were enrolled, of whom 15 with programmed death-ligand 1 (PD-L1) negative tumors. Grade 3 treatment-related adverse events were reported in three patients, leading to permanent discontinuation of treatment in one. No patients experienced grade 4–5 toxicity. Median overall survival time was still not reached at data cut-off. As best overall response, four patients had a partial response (PR), eight had stable disease (SD) and five had progressive disease (PD). Eight patients, including six with PD-L1 negative tumors, were on treatment for more than 12 months. ctDNA was detectable at baseline in 11 plasma samples. A rapid decline in ctDNA to <30% of baseline levels was seen for three patients, two of them radiographic responders and one considered clinically benefiting from therapy for almost one year. Atezolizumab was safely administered concomitant with SBRT, but further trials are needed to assess the efficacy of this combination. ctDNA holds potential as a dynamic biomarker in lung cancer patients receiving immune checkpoint inhibitors.

PD-L1 Expression in Endometrial Serous Carcinoma and Its Prognostic Significance.

PurposeProgrammed death-ligand 1 (PD-L1) has been widely used as a prognostic biomarker and an immunotherapeutic target in numerous cancers, but information on the clinical significance of its expression in endometrial serous carcinoma (ESC) is largely lacking. Here, we evaluate the predictive value of PD-L1 expression in ESC.Materials and MethodsA total of 79 cases of ESC accessioned between January 2003 and September 2015 were selected for further analysis. PD-L1 expression was evaluated in whole tissue sections of these cases by using the tumor proportion score (TPS, cut-off 1%) and combined positive score (CPS, cut-off 1) scoring methods.ResultsOverall, there was a heterogeneous expression of PD-L1, focal or patchy, in ESCs. PD-L1 positivity was observed in 43.0% of ESCs by TPS and 73.4% of ESCs by CPS. Kaplan–Meier survival analysis showed that patients with PD-L1-positive tumors suffered significantly worse OS and PFS, when compared with PD-L1 negative tumors (log-rank p = 0.037 and p = 0.003, respectively). In contrast, PD-L1 positivity by CPS within the ESC cases showed no statistical significance for OS and PFS (log-rank p = 0.720 and p = 0.928, respectively). Multivariate Cox analysis showed that PD-L1 positivity by TPS was significantly associated with PFS (HR = 1.921, p = 0.039) but not OS (HR = 1.229, p = 0.631).ConclusionPD-L1 expression is frequently found in ESC, suggesting a potential role of the PD-1/PD-L1 pathway as a potential therapeutic target for these tumors. PD-L1 expression by TPS also serves as a negative prognostic marker in ESC and implies an unfavorable outcome.

PD-L1 expression and its clinicopathologic and genomic correlation in the non-small cell lung carcinoma patients: An Indian perspective

BackgroundImmunotherapy with checkpoint inhibitor programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) antibodies targeting the cellular immune checkpoints is the present area of interest showing promising results in patients with advanced non-small cell lung cancer (NSCLC). As there is paucity of PD-L1 expression data from the Indian perspective, we studied the correlation of clinicopathologic profile and oncogenic driver mutations in these patients. Materials and methodsSamples from 252 advanced NSCLCs patients were studied for PD-L1 expression through immunohistochemistry using rabbit anti-human PD-L1 monoclonal antibody (clone SP263) on Ventana BenchMark ULTRA autostainer. Simultaneously, genetic mutations were studied by next generation sequencing (for EGFR, ALK, ROS, MET, and BRAF). PD-L1 expression was analyzed for association with clinicopathologic features and various mutations. ResultsPD-L1 positivity was seen in 134 patients (53.2 %). It was twice more prevalent in males than females. No significant correlation was observed between PD-L1 expression with age, gender, site of testing (primary vs. metastatic tumors), smoking status, tumor laterality, stage, or histologic type; however, there was significant difference among solid and acinar types of adenocarcinoma combined together vs. other adenocarcinoma subtypes (p = 0.013), and well and moderately differentiated vs. poorly differentiated tumors (p = 0.022). When types/extent of PD-L1 positivity (≥25 %) were compared with demographics, clinical, and pathologic variables, significant differences were observed across the tumor grades (high-grade vs. low-grade) (p = 0.009) and stages (p = 0.039). The PD-L1 expression failed to demonstrate any statistical significance with oncogenic drivers. High PD-L1 expression (TPS ≥ 50) was observed in 27.6 % patients, and it was more prevalent in female patients (32.4 %), aged ≥60 years (33.8 %), smokers (27.3 %), poorly differentiated (36.8 %) and stage IV tumors (28.2 %). Exon 19 deletion was more prevalent in PD-L1 negative tumors whereas exon 21 substitution (L858R) was seen more in PD-L1 positive tumors. ConclusionsThis is the largest Indian study demonstrating PD-L1 expression in NSCLC patients comparing with clinicopathologic and genomic parameters. PD-L1 expression was significantly associated with high-grade, solid, and acinar types of adenocarcinoma and advanced tumors. High PD-L1 expression was more prevalent in female patients, aged ≥60 years, smokers, and poorly differentiated and stage IV tumors (28.2 %). Exon 19 deletion was more in PD-L1 negative tumors whereas exon 21 substitution (L858R) was more in PD-L1 positive tumors. PD-L1 is a potential predictive marker stratifying patients who benefit from PD-1 pathway-targeted therapy.

Platelet PD-L1 suppresses anti-cancer immune cell activity in PD-L1 negative tumors

Strategies that interfere with the binding of the receptor programmed cell death protein-1 (PD-1) to programmed death ligand-1 (PD-L1) have shown marked efficacy against many advanced cancers, including those that are negative for PD-L1. Precisely why patients with PD-L1 negative tumors respond to PD-1/PD-L1 checkpoint inhibition remains unclear. Here, we show that platelet-derived PD-L1 regulates the growth of PD-L1 negative tumors and that interference with platelet binding to PD-L1 negative cancer cells promotes T cell-induced cancer cytotoxicity. These results suggest that the successful outcomes of PD-L1 based therapies in patients with PD-L1 negative tumors may be explained, in part, by the presence of intra-tumoral platelets. Altogether, our findings demonstrate the impact of non-cancer/non-immune cell sources of PD-L1 in the tumor microenvironment in the promotion of cancer cell immune evasion. Our study also provides a compelling rationale for future testing of PD-L1 checkpoint inhibitor therapies in combination with antiplatelet agents, in patients with PD-L1 negative tumors.

Programmed death ligand-1 expression is associated with stage and histological grade of parotid carcinoma

Background: The immune checkpoint ligand programmed death ligand-1 (PD-L1) is expressed by various cancers, including those of the head and neck. However, the role of PD-L1 is still unknown.Objectives: To investigate the relationship between PD-L1 expression and survival rate in parotid carcinoma.Methods: PD-L1 expression was investigated by immunohistochemical analysis in 127 patients with parotid carcinoma. The relationship between PD-L1 expression and stage, histological grade, and survival was assessed.Results: PD-L1 expression was found in 28.3% of parotid carcinomas, with the expression being higher in tumors with a higher stage, a higher-grade, and node positive cases. However, the 5-year disease-specific survival rate was 82.2% for the patients with PD-L1 positive and 86.9% for those with PD-L1 negative tumors, showing no significant difference.Conclusions: PD-L1 expression was positive in approximately 50% of high- grade carcinomas, which was similar to the level in head and neck squamous cell carcinoma. In patients with other cancers, it has been reported that an anti-PD-1 monoclonal antibody was more effective against tumors with higher PD-L1 expression. Therefore, it could be a possible new therapeutic option for patients with highly malignant parotid tumors that have a poor prognosis.

Prognostic significance of PD-L1 expression and evaluation of microsatellite instability status in patients with retroperitoneal leiomyosarcomas

Background. Leiomyosarcoma is one of the most common types of soft tissue sarcomas. Radical surgical resection with subsequent adjuvant chemotherapy remain the most effective treatment approach. Immunotherapy based on inhibition of PD-L1 (programmed death ligand 1) or its receptor PD1 (programmed death 1) is considered a promising treatment option. Level of PD-L1 expression in tumor cells and presence of microsatellite instability (МSI) could be considered prognostic and predictive markers of disease progression and effectiveness of immunotherapy.The study objective is to determine PD-L1 expression level and МSI status in patients with retroperitoneal leiomyosarcomas and evaluate their effect on overall and recurrence-free survival.Materials and methods. The study included 57 patients with retroperitoneal leiomyosarcomas who underwent surgical or combination treatment. Analysis of clinical and morphological characteristics was performed; results of surgical treatment were researched. Evaluation of PD-L1 expression and MSI status was performed using immunohistochemical and molecular genetic analysis.Results. PD-L1 expression and MSI status were evaluated in 41 patients of 57. In 10 (24 %) of 41 cases, positive PD-L1 expression was observed (expression level 3–50 %). In 1 (2.4 %) patient, the primary tumor and metastatic lesion had low MSI level (MSI-low, MSI-L). Median follow-up was 31 months. In patients with positive PD-L1 expression, higher Ki-67 proliferative index was observed compared to patients with PD-L1 negative tumors (58.8 and 47.8 % respectively; р = 0.02), as well as significantly lower median overall survival for grade II tumors (30 and 105 months; p = 0.043). In grade III leiomyosarcomas, a trend towards lower median overall survival in patients with PD-L1‑negative tumors (31.0 months) compared to patients with PD-L1 expression (61.2 months) (р = 0.11) was observed.Conclusion. Among patients with retroperitoneal leiomyosarcomas, positive expression of PD-L1 was observed in 24 % (10 / 41) of cases and MSI-low status was found in 2.4 % (1 / 41) of cases. In patients with grade 2 tumors, positive PD-L1 expression is associated with significantly lower overall survival. PD-L1 expression in patients with retroperitoneal leiomyosarcomas could be considered a prognostic marker and a potential therapeutic target.

Expression of Immunomodulatory Molecules PD-1, PD-L1, and PD-L2, and their Relationship With Clinicopathologic Characteristics in Endometrial Cancer.

Chemotherapeutic agents are not very effective in treating advanced endometrial cancers (ECs). Recent studies have demonstrated the immune evasion mechanism of tumors and possible remedies. Programmed cell death protein 1 (PD-1), programmed death ligand 1 (PD-L1), and programmed death ligand 2 (PD-L2) are immunomodulator molecules that have been the focus of research in lung cancer, melanoma, and renal cell cancer. However, there are few studies concerning EC. This retrospective study aimed to determine PD-1, PD-L1, and PD-L2 expression immunohistochemically in EC, and to study their correlation with clinicopathologic tumor characteristics. This study comprised 127 patients with EC. Anti PD-1, PD-L1, and PD-L2 antibodies were examined immunohistochemically on sections obtained from tissue microarray paraffin blocks. No staining with PD-1 in tumor cells was seen; however, we found positive staining in tumor cells at 36.2% with PD-L1 and 64.4% with PD-L2, and at 61.6% with PD-1, 36.2% with PD-L1, and 93.2% with PD-L2 in immune cells. When comparing staining and clinicopathologic findings, most of the PD-L1 negative tumors (both in tumor and immune cells) were FIGO Stage I, which was significantly higher than stage II-III-IV tumors (P<0.05). There was a statistically significant association between the FIGO grade and the PD-L1 score in immune cells (P=0.009), and between staining of PD-1, PD-L1, and PD-L2 and age (P=0.004, 0.013, and 0.043, respectively). Interaction between PD-1, PD-L1, and PD-L2 may be a potential target for immunotherapy in elderly and advanced stage EC patients.

Frequent discordance in PD-1 and PD-L1 expression between primary breast tumors and their matched distant metastases

Programmed death-1 (PD-1) is an immune checkpoint that is able to inhibit the immune system by binding to its ligand programmed death-ligand 1 (PD-L1). In many cancer types, among which breast cancer, prognostic and/or predictive values have been suggested for both PD-1 and PD-L1. Previous research has demonstrated discrepancies in PD-L1 expression between primary breast tumors and distant metastases, however data so far have been scarce. We therefore evaluated immunohistochemical expression levels of PD-1 and PD-L1 in primary breast tumors and their paired distant metastases, and evaluated prognostic values. Tissue microarrays from formalin-fixed paraffin-embedded resection specimens of primary breast cancers and their matched distant metastases were immunohistochemically stained for PD-1 and PD-L1. PD-1 was available in both primary tumor and metastasis in 82 patients, and PD-L1 in 49 patients. PD-1 was discrepant between primary tumor and metastasis in half of the patients (50%), PD-L1 on tumor cells was discrepant in 28.5%, and PD-L1 on immune cells in 40.8% of the patients. In primary tumors there was a correlation between PD-1 positivity and a higher tumor grade, and between immune PD-L1 and ER negativity. In survival analyses, a significantly better overall survival was observed for patients with PD-L1 negative primary breast tumors that developed PD-L1 positive distant metastases (HR 3.013, CI 1.201–7.561, p = 0.019). To conclude, PD-1 and tumor and immune PD-L1 seem to be discordantly expressed between primary tumors and their matched distant metastases in about one-third to a half of the breast cancer patients. Further, gained expression of PD-L1 in metastases seems to indicate better survival. This illustrates the need of reassessing PD-1 and PD-L1 expression on biopsies of distant metastases to optimize the usefulness of these biomarkers.

Implications of Programmed Death Ligand-1 Positivity in Non-Clear Cell Renal Cell Carcinoma

The purpose of this study was to assess the prognostic value of programmed death ligand-1 (PD-L1) positivity in a non-clear cell renal cell carcinoma (non-ccRCC) cohort. PD-L1 expression was evaluated by immunohistochemistry (IHC) using formalin-fixed paraffin-embedded (FFPE) specimens from 45 non-ccRCC patients with available tissue. PD-L1 positivity was defined as ≥1% of staining. Histopathological characteristics and oncological outcomes were correlated to PD-L1 expression. Cancer-specific survival (CSS) and recurrence-free survival (RFS) stratified by PD-L1 status were estimated using the Kaplan–Meier method. Median age was 58 years and median follow-up was 40 months. Non-ccRCC subtypes included sarcomatoid (n = 9), rhabdoid (n = 6), medullary (n = 2), Xp11.2 translocation (n = 2), collecting duct (n = 1), papillary type I (n = 11), and papillary type II (n = 14). PD-L1 positivity was noted in nine (20%) patients. PD-L1 positivity was significantly associated with higher Fuhrman nuclear grade (P = 0.048) and perineural invasion (P = 0.043). Five-year CSS was 73.2 and 83% for PD-L1 positive and negative tumors, respectively (P = 0.47). Five-year RFS was 55.6 and 61.5% for PD-L1 positive and negative tumors, respectively (P = 0.58). PD-L1 was expressed in a fifth of non-ccRCC cases and was associated with adverse histopathologic features. Expression of biomarkers such PD-L1 may help better risk-stratify non-ccRCC patients to guide treatment decisions and follow-up strategies.

Clinicopathologic Features of Thymoma With the Expression of Programmed Death Ligand 1

Programmed death ligand 1 (PD-L1) is reportedly expressed in various malignancies and is considered a prognostic factor. We attempted to reveal the usefulness of the PD-L1 expression as a prognostic factor in patients with thymoma. Eighty-one patients with thymoma who underwent surgical resection between 2004 and 2015 were retrospectively reviewed. The PD-L1 expression was evaluated by immunohistochemistry and stratified by the proportion of positive tumor cells. Strong membranous reactivity of the PD-L1 antibody in 1% or more of tumor cells was considered "positive." The association between the PD-L1 expression and the clinicopathologic features was investigated. The PD-L1 expression was positive in 22 patients (27%) and negative in 59 patients (73%). The PD-L1 positivity was significantly associated with type B2 and B3 thymoma (p < 0.001) and stage III and IV disease (p= 0.048). In addition, PD-L1 positive tumors showed a significantly higher maximum standardized uptake value than PD-L1 negative tumors (p= 0.026). The 5-year disease-free survival rate was 82% in PD-L1 positive patients and 88% in PD-L1 negative patients, showing no significant difference (p= 0.57). Furthermore, PD-L1 positivity was not an independent prognostic factor for the disease-free survival on a Cox proportional hazards analysis (p= 0.59). A strong expression of PD-L1 in thymoma was significantly associated with type B2 and B3 and higher pathologic stages. In addition, PD-L1 positivity was associated with an increased maximum standardized uptake value of the tumor. However, patients with PD-L1 positive thymomas did not show a significantly worse prognosis than patients with PD-L1 negative tumors.

Neoadjuvant PD-1 Blockade in Resectable Lung Cancer

BackgroundAntibodies that block programmed death 1 (PD-1) protein improve survival in patients with advanced non–small-cell lung cancer (NSCLC) but have not been tested in resectable NSCLC, a condition in which little progress has been made during the past decade.MethodsIn this pilot study, we administered two preoperative doses of PD-1 inhibitor nivolumab in adults with untreated, surgically resectable early (stage I, II, or IIIA) NSCLC. Nivolumab (at a dose of 3 mg per kilogram of body weight) was administered intravenously every 2 weeks, with surgery planned approximately 4 weeks after the first dose. The primary end points of the study were safety and feasibility. We also evaluated the tumor pathological response, expression of programmed death ligand 1 (PD-L1), mutational burden, and mutation-associated, neoantigen-specific T-cell responses.ResultsNeoadjuvant nivolumab had an acceptable side-effect profile and was not associated with delays in surgery. Of the 21 tumors that were removed, 20 were completely resected. A major pathological response occurred in 9 of 20 resected tumors (45%). Responses occurred in both PD-L1–positive and PD-L1–negative tumors. There was a significant correlation between the pathological response and the pretreatment tumor mutational burden. The number of T-cell clones that were found in both the tumor and peripheral blood increased systemically after PD-1 blockade in eight of nine patients who were evaluated. Mutation-associated, neoantigen-specific T-cell clones from a primary tumor with a complete response on pathological assessment rapidly expanded in peripheral blood at 2 to 4 weeks after treatment; some of these clones were not detected before the administration of nivolumab.ConclusionsNeoadjuvant nivolumab was associated with few side effects, did not delay surgery, and induced a major pathological response in 45% of resected tumors. The tumor mutational burden was predictive of the pathological response to PD-1 blockade. Treatment induced expansion of mutation-associated, neoantigen-specific T-cell clones in peripheral blood. (Funded by Cancer Research Institute–Stand Up 2 Cancer and others; ClinicalTrials.gov number, NCT02259621.)

Abstract CT017: First-in-human PET imaging with the PD-L1 antibody 89Zr-atezolizumab

Abstract Background: Programmed death-ligand 1 (PD-L1) expression has been associated with response to PD-1/PD-L1 inhibition, but responses are also seen in patients with PD-L1 negative tumors when assessed immunohistochemically (IHC) with various antibodies. To help understand these findings, we performed a first-in-human positron emission tomography (PET) imaging study with the anti-PD-L1 antibody atezolizumab labeled with zirconium-89 (89Zr) prior to treatment with atezolizumab to assess normal organ distribution and evaluate tumor tracer uptake in relation to PD-L1 IHC in archival and post-tracer tumor specimen and ultimately to treatment response. Methods: Patients with locally advanced or metastatic non-small cell lung cancer (NSCLC), bladder cancer (BC) or triple-negative breast cancer (TNBC) received 10 mg unlabeled atezolizumab plus 37 MBq 89Zr-atezolizumab (~1 mg) followed by up to 4 PET scans (1 hour, days 2, 4 and 7 post-injection (pi)). Next, after obtaining a tumor biopsy for PD-L1 IHC 8-10 days after tracer injection, patients received atezolizumab (1200 mg) i.v. once every 3 weeks until disease progression (NCT02453984 and NCT02478099). Response was assessed every 6 weeks with RECIST1.1. Normal organ tracer uptake was calculated as percentage of the injected dose/kg (%ID/kg) 4 and 7 days pi, tumor tracer uptake as maximum standardized uptake value (SUVmax) and %ID/kg 7 days pi. Tumor biopsy PD-L1 expression was assessed in tumor cells (TC) and tumor infiltrating immune cells (IC) by HistoGeneX IHC with the SP142 assay (Ventana). Results: In this ongoing trial, 16/25 patients completed the PET series and received atezolizumab at least until the first response assessment. The median follow-up of these patients is 16 weeks (6-40+, NSCLC=6, BC=8, TNBC=2). The highest normal organ 89Zr-atezolizumab uptake was seen in the spleen (16.3±3.6 %ID/kg 4 days and 17.9±3.6 %ID/kg 7 days pi), and uptake in other lymphatic organs (single normal lymph nodes and tonsil) and sites of (chronic) inflammation (e.g. chronic sinusitis and bursitis) were detected. Uptake in liver, kidney and intestine was similar to other antibodies with 7.3±1.6, 5.5±2.0 and 4.7±2.4 %ID/kg, respectively, 7 days pi. Tumor SUVmax ranged between 1.6 and 46.0 (1.8-12.4 %ID/kg), with an up to 9-fold difference within patients, and 4-fold difference between patients. In 4 biopsied lesions with IC/TC 0, 89Zr-atezolizumab uptake calculated as SUVmax was 10.0±3.6 (7.1±1.6 %ID/kg). At this time only 4 biopsies had a IHC score of 2+ on either IC or TC, and there were no biopsies with a score of 3+, limiting the ability to determine correlation of PD-L1 IHC to imaging data. Conclusion: 89Zr-atezolizumab imaging showed high uptake in normal spleen, other normal lymphoid organs and regions of inflammation. Uptake in tumor lesions was heterogeneous within and between patients and even PD-L1 IHC 0 tumors showed clear tracer uptake. Citation Format: Frederike Bensch, Elly van der Veen, Annelies Jorritsma, Marjolijn Lub-de Hooge, Ronald Boellaard, Sjoukje Oosting, Carolien Schröder, Jeroen Hiltermann, Anthonie van der Wekken, Harry Groen, Bernard Fine, Nathan McKnight, Sandra Sanabria Bohorquez, Simon Williams, Luisa Veronese, Christoph Mancao, Adrienne H. Brouwers, Elisabeth de Vries. First-in-human PET imaging with the PD-L1 antibody 89Zr-atezolizumab [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT017. doi:10.1158/1538-7445.AM2017-CT017

Predictive biomarkers of immunotherapy for non-small cell lung cancer: results from an Experts Panel Meeting of the Italian Association of Thoracic Oncology.

Unleashing the potential of immune system to fight cancer has become one of the main promising treatment modalities for advanced non-small cell lung cancer (NSCLC). The knowledge of numerous factors that come into play in the cancer-immunity cycle provide a wide range of potential therapeutic targets, including monoclonal antibodies that inhibits the programmed death-1 (PD-1) checkpoint pathway. Over the last two years, nivolumab, pembrolizumab and atezolizumab received approval for treatment of pretreated advanced NSCLC, and more recently, immunotherapy with pembrolizumab is the new standard of care as first-line in patients with high levels of programmed death-ligand 1 (PD-L1) expression. Selection of patients is mandatory and PD-L1 is the only biomarker currently available in clinical practice. However, PD-L1 staining is an imperfect marker, whose negativity does not exclude a response to immunotherapy, as well as the roughly half of patients are "not-responders" despite high tumor PD-L1 levels. The right cut-off, the differences among various immune checkpoint inhibitors and among various antibody clones, and a not trivial activity reported even in PD-L1 negative tumors are questions still open. New biomarkers beyond to PD-L1 assays as well as new strategies, including combination of immune checkpoint inhibitors are under investigation.

Gastrointestinal stromal tumors: Immune protein expression and clinical outcomes.

124 Background: The immune microenvironment is emerging as an important prognostic factor with potential therapeutic targets for various malignancies. Although programmed death-ligand 1 (PD-L1) and indoleamine 2,3-dioxygenase (IDO) have been studied in some tumor types, significance of their expression in gastrointestinal stromal tumors (GISTs) is largely unknown. Methods: Tissue microarrays at an academic tertiary care center were constructed from pathology files from 1996 to 2016. Immunohistochemistry for PD-L1 and IDO was performed and correlated with tumor size, mitoses, and clinical outcomes. Tumor infiltrating lymphocytes (TILs) were counted using image analysis software. Results: 131 GISTs were analyzed. Median patient age was 64 years (range 30-89); 51.1% were male. Tumor location included 89 stomach (67.9%), 34 small bowel (26.0%), 4 colorectal (3.1%), and 4 other (3.1%). Median follow-up was 58 months. Mean tumor size was 5.6±4.5cm, range 0.5 to 24; mean mitoses were 7.2/50HPF. 19 (14.5%) metastasized to mesentery (n = 8), liver (n = 6), and elsewhere (n = 5). Mean survival was 61 months (range 7-127); 5 patients died of disease (3.8%). PD-L1 immunostain was positive in 89 (67.9%), including 11 of 19 (57.9%) malignant and 78 of 112 (69.6%) benign tumors (p = 0.4). PD-L1 positive tumors were larger (6.3±4.4 vs. 4.4±3.4 cm; p = 0.02) and had more mitoses/50HPF (8.9±5.4 vs. 3.9±3.5; p = 0.006) than PD-L1 negative tumors. IDO immunostain was positive in 116 (88.5%), including 14 of 19 (73.7%) malignant and 102 of 112 (91.1%) benign tumors (p = 0.07). There was no significant difference in size or mitotic count between IDO positive and negative tumors. Mean number of CD8-positive TILs was 168±35/mm2 and mean number of PD-L1 positive TILs was 147±28/mm2 in PD-L1 positive tumors. PD-L1 positive tumors had significantly more TILs than PD-L1 negative tumors (113±21 vs. 104±18; p &lt; 0.001). Conclusions: The majority of GISTs express PD-L1 and IDO. Expression of PD-L1 was associated with increased tumor size and higher mitotic activity. PD-L1 and IDO could play a significant role in the tumor biology of GISTs; immunotherapy targeting one or both may provide novel treatment options.

Expression of Programmed Death Ligand 1 in Penile Cancer is of Prognostic Value and Associated with HPV Status

PD-L1 (programmed death ligand 1) inhibits T-cell function and prevents tumor eradication. This is facilitated by PD-L1 positive tumor cells and PD-L1 positive immune cells, and can be prevented by anti-PD-1 (programmed death 1)/PD-L1 immunotherapy. In advanced penile cancer there is a need for new therapeutic strategies. We investigated PD-L1 expression in penile cancers and compared PD-L1 expression with disease specific survival, lymph node metastases at diagnosis and high risk HPV status in a large patient cohort. A total of 213 primary tumors were immunohistochemically stained for PD-L1 and scored for tumor (percentage), stroma (binary) and PD-L1 positive tumor infiltrating macrophages. Additionally, PD-L1 positive tumors were scored for expression pattern, that is diffuse or predominantly present at the tumor-stroma margin. Staining was successful in 200 tumors, of which 75% were high risk HPV negative. Median followup was 62 months. Of 200 tumors 96 (48%) were PD-L1 positive (scored 1% or greater), of which 59 (62%) had a marginal expression pattern and 79 (82%) were high risk HPV negative (p = 0.03). Compared to PD-L1 negative tumors, the PD-L1 expression patterns had different prognostic values in the whole cohort as well as in the high risk HPV negative subgroup. On multivariable analyses a marginal expression pattern was associated with absent lymph node metastases (OR 0.4) while diffuse expression was associated with poor survival (HR 2.58). These results were more prominent in the high risk HPV negative subgroup (OR 0.25, HR 3.92). PD-L1 was expressed in 48% of penile carcinomas and mainly in high risk HPV negative tumors. The pattern of expression was a prognostic factor as marginal expression was associated with absent lymph node metastases and diffuse expression was associated with poor survival.

Immune infiltration and PD-L1 expression in the tumor microenvironment are prognostic in osteosarcoma.

Osteosarcoma patient survival has remained stagnant for 30 years. Novel therapeutic approaches are needed to improve outcomes. We examined the expression of Programmed Death Ligand 1 (PD-L1) and defined the tumor immune microenvironment to assess the prognostic utility in osteosarcoma. PD-L1 expression in osteosarcoma was examined in two patient cohorts using immunohistochemistry (IHC) (n = 48, n = 59) and expression was validated using quantitative real time PCR (n = 21) and western blotting (n = 9). IHC was used to determine the presence of tumor infiltrating lymphocytes and antigen-presenting cells (APCs) in the tumor. Expression of PD-L1 was correlated with immune cell infiltration and event-free-survival (EFS). The 25% of primary osteosarcoma tumors that express PD-L1 were more likely to contain cells that express PD-1 than PD-L1 negative tumors (91.7% vs 47.2%, p = 0.002). Expression of PD-L1 was significantly associated with the presence of T cells, dendritic cells, and natural killer cells. Although all immune cell types examined were present in osteosarcoma samples, only infiltration by dendritic cells (28.3% vs. 83.9%, p = 0.001) and macrophages (45.5% vs. 84.4%, p = 0.031) were associated with worse five-year-EFS. PD-L1 expression was significantly associated with poorer five-year-EFS (25.0%. vs. 69.4%, p = 0.014). Further studies in osteosarcoma are needed to determine if targeting the PD-L1:PD-1 axis improves survival.