Programmed cell death-ligand 1 expression in oral squamous cell carcinoma is associated with an inflammatory phenotype

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

Introduction

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.

Methods

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.

Results

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).

Discussion

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.

Dynamic Up-Regulation of PD-L1 in the Progression of Oral Squamous Cell Carcinoma

The introduction of immune checkpoint inhibition for recurrent and metastatic head and neck cancer has brought a new treatment option for patients suffering from advanced oral cancers without a chance for curation using surgery or radiotherapy. The application of immune checkpoint inhibitors in most cases is based on the expression levels of PD-L1 in the tumor tissue. To date, there is a lack of data on the dynamic regulation of PD-L1 during disease progression. Therefore, this study aimed to evaluate the expression levels of PD-L1 in a large cohort of patients (n = 222) with oral squamous cell carcinoma including primary and recurrent tumors. Semiautomatic digital pathology scoring was used for the assessment of PD-L1 expression levels in primary and recurrent oral squamous cell carcinoma. Survival analysis was performed to evaluate the prognostic significance of the protein expression at different stages of the disease. We found a significant up-regulation of PD-L1 expression from primary disease to recurrent tumors (mean PD-L1 H-scores: primary tumors: 47.1 ± 31.4; recurrent tumors: 103.5 ± 62.8, p < 0.001). In several cases, a shift from low PD-L1 expression in primary tumors to high PD-L1 expression in recurrent tumors was identified. Multivariate Cox regression analysis did not reveal a significantly higher risk of death (p = 0.078) or recurrence (p = 0.926) in patients with higher PD-L1 expression. Our findings indicate that the exclusive analysis of primary tumor tissue prior to the application of checkpoint blockade may lead to the misjudgment of PD-L1 expression in recurrent tumors.

Soluble Programmed Death-Ligand 1 (sPD-L1) as a Promising Marker for Head and Neck Squamous Cell Carcinoma: Correlations With Clinical and Demographic Characteristics

Background and objective Head and neck squamous cell carcinoma (HNSCC) is a prevalent cancer type that affects the mucosal lining of the upper aerodigestive tract. Soluble programmed death-ligand 1 (sPD-L1) is a significant factor in hindering T cells' function, which prevents cancer cells from being detected by the immune system. This means that sPD-L1 is an essential component in the immune evasion of cancer. This study aimed to explore the potential of sPD-L1 as a prognostic biomarker for patients with HNSCC undergoing concurrent chemotherapy and radiation therapy. Methodology The study included 106 patients with locally advanced HNSCC who received three courses of induction chemotherapy followed by concurrent chemoradiation and 60 healthy subjects as controls. sPD-L1 levels were measured using an enzyme-linked immunosorbent assay (ELISA) kit, and the cutoff value was determined based on receiver operating characteristic (ROC) curve analysis. Results The results showed that sPD-L1 levels were significantly higher in HNSCC patients compared to healthy controls, with a cutoff value of 31.51 pg/mL. Higher sPD-L1 levels were associated with poorer overall survival rates. Conclusions These findings suggest that sPD-L1 may serve as a valuable prognostic biomarker for HNSCC patients undergoing concurrent chemotherapy and radiation therapy. The study highlights the importance of exploring new biomarkers and therapeutic strategies for HNSCC to improve patient outcomes and reduce morbidity and mortality rates associated with this disease.

Expression of PD-L1 is HPV/P16-independent in oral squamous cell carcinoma

Objectives

Study design

Results

Conclusion

Differences in PD-L1 Expression between oral and oropharyngeal squamous cell carcinoma

Treatment of metastasized or recurrent oral (OSCC) and oropharyngeal (OPSCC) squamous cell carcinoma remains challenging. Targeted antibody-based therapy inter alia for PD-1 / PD-L1 axis shows promising results, but whether PD-L1 expression varies between the subentities remains unclear. The expression pattern of PD-L1 (EPR19759 antibody, Abcam, Berlin, Germany) and p16 (CINtech® Histology Kit, Ventana, Oro Valley, USA) was determined immunohistochemically and analyzed by HALO™ Image Analysis Software (Indica Lab, Albuquerque, USA). For PD-L1, combined positivity score (CPS), tumor proportion score (TPS) and histoscore, were assessed and results correlated with epidemiological data. In total, 161 patients (OSCC: n = 78, OPSCC: n = 83) were included. A mean of 43.6% (±34.0%) of the specimen showed increased PD-L1 expression that did not differ quantitatively between subentities (TPS: p = 0.159, CPS: p = 0.078), but qualitatively (histoscore: p = 0.003). In the mean follow-up period (45.6 months), contrary to age (p = 0.006) and advanced T-Status (p = 0.018), PD-L1 expression did not correlate with overall (OS, p = 0.191) and recurrence free survival (RFS: p = 0.193) in both subentities. No correlation of p16 and PD-L1 expression was found (p = 0.844). PD-L1 is differentially expressed between OSCC and OPSCC, however without influence on OS. Furthermore, p16 status was not related to PD-L1 expression. This may have implications for future (immune) therapeutical approaches for oral cancer.

PD-L1 in oral squamous cell carcinoma: A key biomarker from the laboratory to the bedside

Objectives and background: Oral squamous cell carcinoma (OSCC) is a highly malignant disease with an increasing incidence. The need to improve therapeutic strategies for patients affected by OSCC is an urgent challenge. Currently, the advent of immunotherapy represents an important step toward this aim. Programmed cell death‐ligand 1 (PD‐L1), a membrane protein that can be expressed on tumor and inflammatory cells is a key biomarker whose expression is determined by means of immunohistochemistry and is necessary for selecting patients for immunotherapy. Methods: In this study, we review the methods of PD‐L1 assessment and outcomes achieved with immunotherapy in the treatment of OSCC patients. Results: Based on a meta‐analysis we demonstrate a lack of prognostic significance of PD‐L1 in OSCC. Conclusions: We also highlight unresolved issues including difficulties in standardizing PD‐L1 evaluation and discuss future opportunities such as leveraging digital pathology.

Prognosis Value of Immunoregulatory Molecules in Oral Cancer Microenvironment: An Immunohistochemical Study

Objectives: To evaluate the relationship of the immune-checkpoint PD-1/PD-L1 with the clinical evolution of OSCC; to assess survival in OSCC based on the characteristics of TME and histologic risk score; to evaluate the clinical and histopathological relationship of OSCC with immunological TME. Material and Methods: A retrospective study was carried out on 65 samples from patients with OSCC on the floor of the mouth or tongue. Clinicopathological variables and the expression of the biomarkers PD-1, PD-L1, FoxP3, CD4, CD8, CSF1R, and p16 were recorded. The relationship of the clinical and histological variables with the expression of the biomarkers and survival was studied. Results: The univariate and multivariate analysis indicated that positive PD-1 expression was an independent protective factor for survival (overall, disease-free, disease-specific survival) and that high PD-L1 also improved survival. Poorly differentiated histological grades and metastasis were associated with a worse prognosis. Conclusions: PD-1 is a protective survival factor that is maintained independently of PD-L1 expression. High values of PD-L1 expression also improve survival. Higher expression of PD-1 is observed in smaller tumors, and higher expression of PD-L1 is more likely in women. No relationship between the tumor microenvironment and histologic risk score was found to influence the survival patterns studied in the OSCC. There is no evidence of a relationship between the histopathological features and the studied markers, although the positive PD-1 and PD-L1 cases have a lower risk of a high WPOI score, and positive PD-1 expression was associated with a lower DOI.

Prognostic Value of Programmed Death Ligand-1 Expression in Solid Tumors Irrespective of Immunotherapy Exposure: A Systematic Review and Meta-Analysis

BACKGROUND

The programmed cell death-1/programmed cell death ligand-1 (PD-L1) pathway, which plays a crucial role in cancer immune surveillance, is the target of several approved immunotherapeutic agents and is used as a predictive biomarker in some solid tumors. However, its use as a prognostic marker (i.e., regardless of therapy used) is not established clearly with available data demonstrating inconsistent prognostic impact of PD-L1 expression in solid tumors.

METHODS

We conducted a systematic literature search of electronic databases and identified publications exploring the effect of PD-L1 expression on overall survival and/or disease-free survival. Hazard ratios were pooled in a meta-analysis using generic inverse-variance and random-effects modeling. We used the Deeks method to explore subgroup differences based on disease site, stage of disease, and method of PD-L1 quantification.

RESULTS

One hundred and eighty-six studies met the inclusion criteria. Programmed cell death ligand-1 expression was associated with worse overall survival (hazard ratio 1.33, 95% confidence interval 1.26-1.39; p < 0.001). There was significant heterogeneity between disease sites (subgroup p = 0.002) with pancreatic, hepatocellular, and genitourinary cancers associated with the highest magnitude of adverse outcomes. Programmed cell death ligand-1 was also associated with worse overall disease-free survival (hazard ratio 1.19, 95% confidence interval 1.09-1.30; p < 0.001). Stage of disease did not significantly affect the results (subgroup p = 0.52), nor did the method of quantification via immunohistochemistry or messenger RNA (subgroup p = 0.70).

CONCLUSIONS

High expression of PD-L1 is associated with worse survival in solid tumors albeit with significant heterogeneity among tumor types. The effect is consistent in early-stage and metastatic disease and is not sensitive to method of PD-L1 quantification. These data can provide additional information for the counseling of patients with cancer about prognosis.

Evaluation of programmed death ligand 1 expression in cytology to determine eligibility for immune checkpoint inhibitor therapy in patients with head and neck squamous cell carcinoma

BACKGROUND

Immune checkpoint inhibitors targeting the programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathway have recently emerged as a frontline treatment for head and neck squamous cell carcinoma (HNSCC). The evaluation of PD-L1 expression by immunohistochemistry in histologic samples is used to determine the eligibility of patients with HNSCC for immunotherapy. Patients with newly diagnosed HNSCC are frequently diagnosed by fine-needle aspiration (FNA) of lymph nodes with metastatic disease. However, the evaluation of PD-L1 expression with the proposed combined positive score (CPS) has not been well established in cytology specimens.

METHODS

This study retrospectively identified 21 HNSCC patients with a known PD-L1 status from histologic specimens and matched FNA specimens with tumor cells on cell blocks (CBs). The CB sections were stained with a PD-L1 antibody (22C3 clone). All cases were scored with CPS and the tumor proportion score (TPS).

RESULTS

The data showed substantial concordance between cytologic and histologic specimens for CPS (agreement, 76.2%; κ = 0.607) and TPS (agreement, 76.2%; κ = 0.607). With histology used as a reference standard, the positive predictive value was 100% for both CPS and TPS, whereas the negative predictive value was 57.1% for CPS assessments and 50% for TPS assessments.

CONCLUSIONS

PD-L1 expression in HNSCC cytology samples has high concordance with paired histologic samples. PD-L1 CPS evaluation is feasible in HNSCC cytology CBs and can act as a surrogate for determining eligibility for immunotherapy in cases in which a histologic specimen is not readily available.

PD-L1 evaluation in head and neck squamous cell carcinoma: Insights regarding specimens, heterogeneity and therapy

Immunohistochemical assessment with combined positive score (CPS) of programmed death-ligand 1 (PD-L1) is the prerequisite for administration of checkpoint inhibitor therapy in head and neck squamous cell carcinoma (HNSCC). Practicing pathologists are required to assess PD-L1 in routinary work and can be faced up with practical issues not always addressed in clinical trials or guidelines, such as choice of specimen to test, the intrinsic heterogeneity in PD-L1 expression in tumors and the potential impact of already administered therapy, given that patients' material can be procured at several times of cancer natural history. In the present work, we review and discuss the recent literature regarding the assessment of PD-L1 in HNSCC from the perspective of the practicing pathologist, providing some evidence on the single issues. It emerges a general trend to an underestimation of PD-L1 expression in biopsies compared to resection specimens and to a higher degree of positivity in metastatic lymph nodes in respect to primary tumors. Moreover, therapy shows to have contrasting effect on PD-L1 expression. Although further studies are needed, taking into account the intrinsic heterogeneity in PD-L1 expression and the conflicting evidences, it may be speculated that the most recent material of patients in respect to the natural history of tumor can be the most reliable to evaluate PD-L1 expression.

High PD-L1 Expression on Tumor Cells Indicates Worse Overall Survival in Advanced Oral Squamous Cell Carcinomas of the Tongue and the Floor of the Mouth but Not in Other Oral Compartments

The markers of the tumor microenvironment (TME) are promising prognostic and predictive factors in oral squamous cell carcinoma (OSCC). The current study aims to analyze the immunohistochemical expression of programmed cell death-ligand 1 (PD-L1) and interleukin-33 (IL-33) in a cohort of 95 chemonaïve OSCCs. PD-L1 and IL-33 were assessed separately in tumor cells (TCs) and tumor-infiltrating lymphocytes (TILs). High PD-L1 expression in TILs was associated with better overall survival (OS) in univariate analysis. Tumors localized in the floor of the oral cavity and tongue tended to have a lower percentage of PD-L1-positive TCs when compared to other locations. PD-L1 expression on TCs had no prognostic significance when the whole cohort was analyzed. However, along with the T descriptor (TNM 8th), it was included in the multivariable model predicting death in carcinomas of the floor of the oral cavity and tongue (HR = 2.51, 95% CI = 1.97-5.28). In other locations, only nodal status was identified as an independent prognostic factor in multivariate analysis (HR = 0.24, 95% CI = 0.08-0.70). Expression of IL-33 had no impact on survival, but it was differently expressed in various locations. In conclusion, the prognostic significance of PD-L1 in oral cancer depends on the tumor site and type of cell expressing immune checkpoint receptor (TCs vs. TILs).

Immune checkpoint analysis in lip cancer

The aim of this study was to establish whether PD-L1, PD-1, and markers of the tumor microenvironment (CD4, CD8, FOXP3) could have a prognostic value in squamous cell carcinoma of the lip (LSCC). In patients with histologically proven LSCC, tumor specimens were stained using immunohistochemistry (for PD-1, PD-L1, CD4, CD8, and FOXP3) on paraffin-embedded tissues. Patients with (N+) and without (N-) nodal metastasis were stratified and matched to each other according to prognostically relevant clinicopathological parameters. 58 patients (29 N+ and 29 N-) were included. PD-L1 expression was positive (>1%) in 56.1% (n = 33) of all LSCC cases, but its expression did not differ significantly between metastasis groups (65.5% in N+ versus 48.3% in N-; p = 0.144). Nodal disseminated LSCC showed a tendency for higher PD-L1 expression. None of the analyzed markers showed significant correlation with the risk for nodal disease, or revealed significant prognostic value. Due to their significant expression, PD-L1 and PD-1 are potential targets for checkpoint inhibitor therapy in LSCC. Their expression should be analyzed in advanced and metastasized LSCC cases.

Transcriptomic and Immunophenotypic Characterization of Tumor Immune Microenvironment in Squamous Cell Carcinoma of the Oral Tongue

The tumor immune microenvironment of oral tongue squamous cell carcinoma may be accountable for differences in clinical behavior, particularly between different age groups. We performed RNA expression profiling and evaluated tumor infiltrating lymphocytes (TILs) and their T-cell subsets in order to assess the functional status of oral tongue squamous cell carcinoma tumor microenvironment and detect potentially clinically useful associations. Archival surgical pathology material from sixteen oral tongue squamous cell carcinoma patients was microscopically evaluated for TIL densities. RNA was extracted from macrodissected whole tumor sections and normal controls and RNA expression profiling was performed by the NanoString PanCancer IO 360 Gene Expression Panel. Immunostains for CD4, CD8 and FOXP3 were evaluated manually and by digital image analysis. Oral tongue squamous cell carcinomas had increased TIL densities, numerically dominated by CD4 + T cells, followed by CD8 + and FOXP3 + T cells. RNA expression profiling of tumors versus normal controls showed tumor signature upregulation in inhibitory immune signaling (CTLA4, TIGIT and PD-L2), followed by inhibitory tumor mechanisms (IDO1, TGF-β, B7-H3 and PD-L1). Patients older than 44 years showed a tumor microenvironment with increased Tregs and CTLA4 expression. Immunohistochemically assessed CD8% correlated well with molecular signatures related to CD8 + cytotoxic T-cell functions. FOXP3% correlated significantly with CTLA4 upregulation. CTLA4 molecular signature could be predicted by FOXP3% assessed by immunohistochemistry (R2 = 0.619, p = 0.026). Oral tongue squamous cell carcinoma hosts a complex inhibitory immune microenvironment, partially reflected in immunohistochemically quantified CD8 + and FOXP3 + T-cell subsets. Immunohistochemistry can be a useful screening tool for detecting tumors with upregulated expression of the targetable molecule CTLA4.

Predictive factors in the treatment of oral squamous cell carcinoma using PD-1/PD-L1 inhibitors

Due to immune impairment and lymphocyte enrichment of oral squamous cell carcinoma (OSCC), anti-PD-1/PD-L1 therapy is regarded as a potential treatment option. However, tumor heterogeneity, differences in the immune conditions of patients, and the interrelation between tumor cells and stromal cells within the tumor microenvironment (TME) could affect the therapeutic efficacy of immune checkpoint blockades. Therefore, to maximize the benefit of blockade PD-1/PD-L1 axis, to find an efficient predictor (the possible clinical parameters or biological factors) before treatment are of great importance. In this review, we discuss the advantages of anti-PD-1/PD-L1 therapy for OSCC patients and find three respects that are currently available in predicting curative effect. Firstly, OSCC with high PD-L1 expression evaluating by immunohistochemistry (high tumor proportion score (TPS) and combined positive score (CPS)) are considered to be suitable for anti-PD-1/PD-L1 therapy. Secondly, gene-level predictive biomarkers including high metastatic mismatch repair deficiency (dMMR) signature or enrichment of interferon-γ and PD1 signaling pathway is expected to be favorable factors. Besides, PET/CT parameters (SUV_max, MTV, TLG) are proved to be correlated with PD-L1 expression, and some newly developed immunoPET probes are enlarging the application of PET/CT in predicting therapeutic efficacy of PD-1/PD-L1 inhibitors.

Programmed death ligand-1 (PD-L1) as a predictive marker for immunotherapy in solid tumours: a guide to immunohistochemistry implementation and interpretation

Immunotherapy with checkpoint inhibitors is well established as an effective treatment for non-small cell lung cancer and melanoma. The list of approved indications for treatment with PD-1/PD-L1 checkpoint inhibitors is growing rapidly as clinical trials continue to show their efficacy in patients with a wide range of solid tumours. Clinical trials have used a variety of PD-L1 immunohistochemical assays to evaluate PD-L1 expression on tumour cells, immune cells or both as a potential biomarker to predict response to immunotherapy. Requests to pathologists for PD-L1 testing to guide choice of therapy are rapidly becoming commonplace. Thus, pathologists need to be aware of the different PD-L1 assays, methods of evaluation in different tumour types and the impact of the results on therapeutic decisions. This review discusses the key practical issues relating to the implementation of PD-L1 testing for solid tumours in a pathology laboratory, including evidence for PD-L1 testing, different assay types, the potential interchangeability of PD-L1 antibody clones and staining platforms, scoring criteria for PD-L1, validation, quality assurance, and pitfalls in PD-L1 assessment. This review also explores PD-L1 IHC in solid tumours including non-small cell lung carcinoma, head and neck carcinoma, triple negative breast carcinoma, melanoma, renal cell carcinoma, urothelial carcinoma, gastric and gastroesophageal carcinoma, colorectal carcinoma, hepatocellular carcinoma, and endometrial carcinoma. The review aims to provide pathologists with a practical guide to the implementation and interpretation of PD-L1 testing by immunohistochemistry.

PD-L1 expression in tongue squamous cell carcinoma

PURPOSE

Immune checkpoint proteins programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) are important therapeutic targets for head and neck cancer. This large-scale case study aimed to analyze tongue squamous cell carcinomas (SCCs) and evaluate the correlation between PD-L1 expression and clinical prognosis. So far, this study is the largest case study on PD-L1 expression in tongue SCCs.

METHODS

This is a case-control study that analyzed 121 tongue SCCs. Paraffin-embedded sections and clinical data were obtained retrospectively and immunohistochemistry with PD-L1 was performed.

RESULTS

11.6% contained ≥ 50% of PD-L1-positive cells, 57.1% of these cases had a poor prognosis with nodal metastasis. Among cases of T1/2 primary lesions with nodal metastasis, cases of high PD-L1 expression had a significantly shorter disease-free survival than cases of no PD-L1 expression (p = 0.018). The hazard ratio for high PD-L1 expression was 3.21 (95 per cent CI, 1.26-8.72) compared with no PD-L1 expression after adjusting for other factors.

CONCLUSIONS

These data indicate that PD-L1 upregulation in tongue SCCs is associated with a more advanced stage and shorter disease-free survival. PD-1/PD-L1 inhibitors might hence constitute potential adjuvant therapy for tongue SCCs with PD-L1 upregulation.

Immune Checkpoint Inhibitors in Oral Cavity Squamous Cell Carcinoma and Oral Potentially Malignant Disorders: A Systematic Review

Cancers of the oral cavity cause significant cancer-related death worldwide. While survival rates have improved in recent years, new methods of treatment are being investigated to limit disease progression and to improve outcomes, particularly in oral cavity squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMD). The emerging treatment modality of immunotherapy targets immune checkpoint molecules including PD-1 and its ligand PD-L1, CTLA-4, LAG-3, and TIM-3 to enhance the host immune response against tumours, and to limit the growth and progression of cancer cells. In this systematic review, we searched five databases for keywords pertaining to oral cancers and OPMDs, along with immune checkpoint inhibitors, in order to summarize the current status of their use and efficacy in these diseases. A total of 644 different articles were identified between 2004 and 2019, with 76 deemed suitable for inclusion in the study, providing a total of 8826 samples. Combined results show expression of PD-1 and PD-L1 in the majority of OPMD and OSCC samples, with expression correlating with increased progression and decreased survival rates. Immunotherapy agents pembrolizumab and nivolumab target PD-1 and have been shown to prolong survival rates and improve disease outcomes, especially in combination with chemotherapy or radiotherapy. Despite the equivocal nature of current evidence, there is support for the prognostic and predictive value of immune checkpoint molecules, especially PD-L1, and many studies provide support for the effective use of immune checkpoint inhibitors in the management of OSCC. Limited data is available for OPMD, therefore this should be the focus of future research.

Clinicopathological and prognostic significance of PD-L1 in oral cancer: A preliminary retrospective immunohistochemistry study

OBJECTIVE

To evaluate the relation between PD-L1 expression in oral cavity squamous cell carcinomas and clinicopathological features as well as survival outcomes.

METHODS

A retrospective immunohistochemical study was carried out on 55 archived tumours from 55 patients. Tumours were stained for PD-L1 and scored by the proportion of tumour cells with positive membranous staining. PD-L1 scores were compared to the patient's clinicopathological characteristics for any significant associations. Kaplan-Meier curves were constructed for PD-L1 positive and negative tumours to investigate any advantage to survival.

RESULTS

Positive PD-L1 staining was found in 58% of tumours and was significantly more likely in non-smokers, non-drinkers and in tongue squamous cell carcinomas. Increased PD-L1 was also associated with increased lymphocyte infiltration as well as PD-L1 staining in lymphocytes and the epithelium adjacent to tumour invasion. No survival benefit was seen from PD-L1 expression in tumour cells.

CONCLUSIONS

PD-L1 expression is more common in non-smokers and non-drinkers, and its presence in the adjacent non-tumour epithelium suggests it may be involved in early oncogenesis.

PD-L1 in squamous cell carcinoma of the oral tongue shows gender-specific association with prognosis

OBJECTIVE

To use alternative quantitation approaches to clarify the clinical implication of programmed cell death ligand 1 (PD-L1) in squamous cell carcinoma of the oral tongue (SCCOT).

MATERIALS AND METHODS

Ventana SP263 immunohistochemistry assay and a multiplicative QuickScore method were applied to quantify PD-L1 in tumor and surrounding immune cells from 101 patients with SCCOT. Tumor-infiltrating immune cells were estimated from bulk tissue transcriptional profiles of 25 patients. Circulating PD-L1 levels were measured in serum from 30 patients using an electrochemiluminescence assay platform.

RESULTS

We found higher tumor cell PD-L1 levels in females than males (p = .019). For patients with low PD-L1 in tumor cells, better survival was seen in males than females (overall survival p = .021, disease-free survival p = .020). Tumor-infiltrating natural killer T cells, immature dendritic cells, and M1 macrophages were positively associated with tumor cell PD-L1 (p < .05).

CONCLUSIONS

Our data confirmed the significance of gender on tumor cell PD-L1 expression and demonstrated combined effects of gender and PD-L1 levels on clinical outcome in patients with SCCOT. The data also indicated the involvement of specific immune cell types in PD-L1-regulated immune evasion.

Prognostic and clinicopathological significance of PD-L1 overexpression in oral squamous cell carcinoma: A systematic review and comprehensive meta-analysis

BACKGROUND

The presence of Programmed Death-Ligand 1 protein (PD-L1) in oral squamous cell carcinoma (OSCC) may indicate an ability to evade immune response and has been suggested as a prognostic marker, but there is controversy in the literature.

OBJECTIVE

To review the scientific evidence of a prognostic role for PD-L1 levels in OSCC.

METHODS

PubMed, Embase, Web of Science, and Scopus were searched for studies published on or before March 02, 2019. Studies measuring PD-L1 levels by immunohistochemistry (IHC) in OSCC were included. Study quality was assessed using the QUIPS tool. Meta-analysis was performed for survival outcomes and clinic-pathological parameters.

RESULTS

26 articles were included comprising 2532 patients. Analysis of studies measuring PD-L1 expression in the cell membrane showed a worse prognosis for disease-specific survival (HR = 1.74, 95% CI = 1.14-2.66, p = 0.01) and disease-free survival (HR = 1.56, 95% CI = 1.16-2.09, p = 0.003). PD-L1 overexpression was more likely in females (OR = 0.69, 95% CI = 0.53-0.91, p = 0.008), non-smokers (OR = 0.45, 95% CI = 0.27-0.75, p = 0.002), non-drinkers (OR = 0.40, 95% CI = 0.16-0.97, p = 0.04), advance stage tumours (OR = 1.63, 95% CI = 1.00-2.64, p = 0.05) and in tumours with high levels of PD-1 (OR = 33.36, 95% CI = 1.88-591.69, p = 0.02), CD4+ (OR = 3.25, 95% CI = 1.36-7.76, p = 0.008) and CD8+ (OR = 3.63 , 95% CI = 1.20-10.99, p = 0.02).

CONCLUSION

This meta-analysis found a worse prognosis in OSCCs overexpressing PD-L1 in the cell membrane as measured by disease specific survival and disease-free survival. We also found positive correlations between PD-L1 overexpression and advanced tumours, females, non-smokers, non-drinkers and high levels of tumour PD-1, CD4, and CD8.

Clinicopathological Features of Programmed Cell Death-ligand 1 Expression in Patients with Oral Squamous Cell Carcinoma

Objective

Programmed cell death-ligand 1 (PD-L1) expression has been shown to play important roles in various types of cancer. However, the role of PD-L1 expression has not been conclusively reported in patients with oral squamous cell carcinoma (OSCC). Accordingly, in this meta-analysis, we investigated the clinicopathological value of PD-L1 expression in patients with OSCC.

Methods

Google Scholar, PubMed, EMBASE, and CNKI databases were searched to find relevant studies published through to September 16, 2019. The relationships between PD-L1 expression in patients with OSCC and clinicopathological features were assessed using risk ratio (RR) and 95% confidence intervals (CIs).

Results

Sixteen studies including 1989 participants were included. The results indicated that high PD-L1 expression was correlated with sex (RR = 1.28, 95% CI: 1.16-1.42, P < 0.001), N stage (RR = 1.19, 95% CI: 1.06-1.33, P = 0.003), M stage (RR = 1.64, 95% CI: 1.01-2.66, P = 0.044), low differentiation (RR = 1.16, 95% CI: 1.01-1.33, P = 0.034), and human papilloma virus infection (RR = 1.38, 95% CI: 1.14-1.68, P = 0.001), but unrelated to TNM stage or T stage. There was no significant publication bias in the studies included in this analysis.

Conclusions

This meta-analysis revealed that high PD-L1 expression in patients with OSCC was correlated with clinicopathological features. Further large-scale studies are necessary to confirm our results.

Relationship of programmed death ligand-1 expression with clinicopathological features and prognosis in patients with oral squamous cell carcinoma: A meta-analysis

BACKGROUND

Programmed death ligand-1 (PD-L1) expression is related to the prognosis of many solid tumors; however, its prognostic value in oral squamous cell carcinoma (OSCC) remains unclear. Here, a meta-analysis was performed to estimate the association of PD-L1 expression with prognosis and clinicopathological features in patients with OSCC.

METHODS

PubMed, Web of Science, EMBASE, Cochrane Library, and CNKI databases were searched to find relevant studies for identification of the association of PD-L1 expression with clinicopathological features and overall survival (OS) in patients with OSCC. The strength of the association of PD-L1 expression with clinicopathological features and OS in patients with OSCC was assessed according to the relative risk (RR), hazard ratio (HR), and 95% confidence interval CI (CI).

RESULT

Twenty-three studies (including 3217 patients with OSCC) were evaluated. The meta-analysis showed that positive PD-L1 expression was significantly correlated with OS in patients with OSCC (HR = 1.00, 95% CI = 0.76-1.30, p = 0.284). Positive PD-L1 expression was significantly correlated with sex (RR = 1.22, 95% CI = 1.07-1.38, p = 0.002), histological differentiation (RR = 1.15, 95% CI = 1.02-1.30, p = 0.020), distant metastasis (RR = 0.68, 95% CI = 0.54-0.86, p = 0.011), lymph node metastasis status (RR = 0.83, 95% CI = 0.76-0.91, p < 0.001), TNM stage (RR = 0.81, 95% CI = 0.73-0.89, p < 0.001), and human papilloma virus infection status (RR = 1.30, 95% CI = 1.04-1.62, p = 0.019), but was not correlated with T stage and tumor recurrence.

CONCLUSION

High PD-L1 expression in OSCC was not related to OS. However, high PD-L1 expression was significantly related to certain clinicopathological features. Thus, positive PD-L1 expression may be a biomarker of poor prognosis in patients with OSCC.

Anti-PD-L1-modified and ATRA-loaded nanoparticles for immuno-treatment of oral dysplasia and oral squamous cell carcinoma

Aim: To develop nanomedicines for immuno-therapy of oral dysplasia and oral squamous cell carcinoma. Materials & methods: All-trans retinoic acid (ATRA)-poly(lactide-co-glycolide acid) (PLGA)-poly(ethylene glycol) (PEG)-programmed death-ligand 1 (PD-L1) nanomedicines were fabricated by loading ATRA into PLGA-PEG nanocarriers and modification using an anti-PD-L1 antibody. Results: ATRA-PLGA-PEG-PD-L1 nanoparticles showed fast cellular uptake, significantly inhibited proliferation and induced apoptosis in DOK and CAL27 cells. Moreover, in C3H tumor-bearing mice, ATRA-PLGA-PEG-PD-L1 nanoparticles more specifically targeted tumor cells, enhanced anticancer activity and reduced side effects when compared with free ATRA. Furthermore, CD8+ T cells were activated around PD-L1 positive cells in the tumor microenvironment after treatment. Conclusion: ATRA-PLGA-PEG-PD-L1 nanoparticles had low toxicity, high biocompatibility and specifically targeted oral dysplasia and squamous carcinoma cells both in vitro and in vivo.

Clinicopathological and prognostic significance of PD-1/PD-L1 axis expression in patients with tongue squamous cell carcinoma

Tongue squamous cell carcinoma (TSCC) is more aggressive than other head and neck tumors, and the prognosis for patients with advanced TSCC is poor. At present, comprehensive treatment based on surgery as the main method is not effective for patients with advanced TSCC. The application of PD-1/PD-L1 immunocheckpoint inhibitor alone in patients with TSCC has not been reported. To explore the role of PD-1/PD-L1, we investigated the expression of PD-1 and PD-L1 in TSCC and analyzed the relationship between the expression of PD-1 and PD-L1 and the related clinicopathological parameters and survival prognosis. The expression of PD-1 was significantly associated with palindromia (p = .015) and maximum diameter (p = .043). The expression of PD-L1 in tumor cells was significantly associated with N stage (P = .024), chemotherapy (p = .032), and clinical stage (p = .019). The expression of PD-L1 in infiltrating lymphocytes was significantly associated with palindromia (p = .030). Univariate and multivariate Cox analyses for prognoses of patients showed significant prognostic factors of overall survival and relapse-free survival. The high expression of PD-L1 on infiltrating lymphocytes for OS and RFS was an independent protective factor for patients with TSCC. The high expression of PD-1 on infiltrating lymphocytes and clinical stage for OS and RFS were independent risk factors for patients with TSCC. The data provide a reference for clinical treatment of TSCC with immunotherapy.

The different role of PD-L1 in head and neck squamous cell carcinomas: A meta-analysis

Programmed cell death-ligands 1 (PD-L1) is a promising immune target for tumor immunotherapy. We conducted this meta-analysis to investigate association between PD-L1 expression and clinicopathological characteristics of head and neck squamous cell carcinomas (HNSCC). Electronic databases were searched for eligible studies. Hazard ratio (HR) with 95 % confidence interval (CI) were extracted to assess the relationship between PD-L1 expression and overall survival (OS) and disease-free survival (DFS) of patients. Odds ratio (OR) with 95 %CI were applied to assess the association between PD-L1 expression and clinicopathological features. A total of 1729 patients were identified for this meta-analysis. PD-L1 expression was higher in female patients in HNSCC (OR = 0.58, 95 %CI:0.44-0.76). In oral squamous cell carcinoma (OSCC), female(OR = 0.56, 95 %CI: 0.41-0.77)and lower grade(OR = 0.48, 95 %CI: 0.24-0.93)were associated with the higher PD-L1 level. There was no significant association between OS and PD-L1 in OSCC patients (HR = 0.89, 95 %CI: 0.37-2.14). In oropharyngeal squamous cell carcinoma (OPSCC), PD-L1 was overexpressed in younger patients (OR = 0.43, 95 %CI: 0.21-0.86), higher tumor grade (OR = 2.46, 95 %CI: 1.38-4.37)and positive HPV status (OR = 2.09, 95 %CI:1.42-3.07). No significant correlation was detected between PD-L1 expression and OS in OPSCC patients (HR = 0.78, 95 %CI: 0.57-1.06). However, the higher PD-L1 expression in tumor cells indicated a better DFS of OPSCC (HR = 0.34, 95 %CI: 0.18-0.67). This meta-analysis demonstrated that PD-L1 overexpression in HNSCC associated with female patients. However, no significant difference was observed in OS or DFS, except the DFS in OPSCC.

Association of PD-L1 expression in oral squamous cell carcinoma with smoking, sex, and p53 expression

OBJECTIVES

The aim of this study was to investigate the association between oral cavity squamous cell carcinoma (OSCC) and PD-L1 expression, and smoking, and p53 expression.

STUDY DESIGN

Histologic review of archival slides of patients with OSCC, obtained from the Sydney Head and Neck Cancer Institute database from 1995 to 2015, was undertaken with tissue microarray construction and immunohistochemistry to identify PD-L1 and p53 expression.

RESULTS

Of the 255 patients identified, PD-L1 expression was observed in 70 (27.5%) and more commonly in females (odds ratio [OR] = 2.19; P = .005). PD-L1 expression of 1% or greater was associated with p53 expression (P = .019) and associated with absence of smoking (P = .06). PD-L1 expression, at 1%, was not significantly associated with overall survival (P = .482), disease-specific survival (P = .864), and disease-free survival (P = .731).

CONCLUSIONS

Our data demonstrate that PD-L1 expression of 1% or greater is more frequent in OSCC in females, nonsmokers, and in patients with p53-positive OSCC. These findings have important implications for immune therapy for OSCC.

Expression of programmed cell death-ligand 1 in oral squamous cell carcinoma and oral leukoplakia is associated with disease progress and CD8+ tumor-infiltrating lymphocytes

OBJECTIVE

In recent years, monoclonal antibodies targeting programmed cell death-ligand 1 (PD-L1) have become a promising cancer immunotherapy. However, the role of PD-L1 in oral squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMDs), including oral leukoplakia (OLK), remains controversial. The aim of the present study was to investigate the expression level of PD-L1 in OSCC and OPMDs, and examine its relationship with CD8 expression and different clinicopathological features.

METHOD

Expression of PD-L1 and CD8 were conducted in 41 OSCC, 21 OLK, and 25 normal mucosa samples by immunohistochemistry. Then, the density of PD-L1 expression was measured, and its correlation with CD8 expression and different clinicopathological features was analyzed.

RESULTS

PD-L1 protein was detected in 97.6% of OSCC, 61.9% of OLK, and 0% of normal tissues. PD-L1 was highly expressed in human OSCC tissue (P < 0.0001), when compared to both OLK and control tissues. PD-L1 positivity was significantly associated with CD8 density (P < 0.0001, r = 0.8491). The PD-L1 high expression OSCC group displayed a trend for improved overall survival (OS) and disease-free survival (DFS) compared to the low expression group, although the differences were not significant. Moreover, the expression level of PD-L1 in OSCC was positively correlated with the pathological grade (P < 0.0001), but it was independent of age, gender, smoking, drinking, tumor size, lymph node status, or recurrence (P > 0.05). Also, there was a significant upregulation of PD-L1 expression observed in the OLK group compared to the control group (P < 0.0001). PD-L1 positivity in OLK patients was associated with gender and smoking habits (P < 0.05), but it did not correlate with age, drinking, or dysplasia (P > 0.05).

CONCLUSION

The upregulation of PD-L1 may be associated with disease progress and CD8+ tumor-infiltrating lymphocytes in oral premalignant and malignant lesions.

An update of knowledge on PD-L1 in head and neck cancers: Physiologic, prognostic and therapeutic perspectives

Programmed cell death-ligand 1 (PD-L1) is a transmembrane protein that acts as a co-inhibitory factor in the immune response. Its receptor, programmed cell death protein 1 (PD-1), is found on immune cells, where binding to PD-L1 can reduce the proliferation of PD-1-positive cells, inhibit their cytokine secretion and induce apoptosis. PD-L1 in immune-privileged tissue plays a crucial role in peripheral tolerance. PD-L1 can be overexpressed in various malignancies, including oral squamous cell carcinoma, where it can attenuate the host immune response to tumour cells and has been associated with a worse prognosis. Monoclonal antibody therapies targeting the PD-1:PD-L1 axis have shown initial promise, but further research is needed to identify which patients will benefit. We provide an update of knowledge on PD-L1, including its structure, function and regulation. We also review studies on the overexpression of PD-L1 in cancer, specifically oral squamous cell carcinoma, and explore its potential value as a therapeutic target.

Prognostic value of immune checkpoint molecules in head and neck cancer: a meta-analysis

Immune checkpoint molecules are important targets in cancer immunotherapy, but their association with prognosis in patients with head and neck cancer is controversial. In this meta-analysis, we searched for 12 immune checkpoint molecules in the PubMed, Embase and Cochrane Library databases and retrieved 52 studies with 7127 participants. Among the molecules included in the search, indoleamine 2, 3-dioxygenase (IDO), programmed death ligand 1 (PD-L1), and programmed death 1 (PD-1) met the inclusion criteria for further analysis. Higher expression of IDO was associated with poorer overall survival in head and neck cancer patients (P = 0.011), but higher expression of PD-L1 correlated with better overall survival specifically in nasopharyngeal carcinoma patients (P = 0.01). In a sensitivity analysis, higher PD-L1 expression correlated with better progression-free survival (P = 0.043), and was associated with better overall survival in Caucasian subjects (P = 0.02), nasopharyngeal carcinoma patients (P = 0.015), and studies with small sample sizes (P = 0.001). PD-1 had no prognostic significance. There was no publication bias affecting the results. Thus, among the immune checkpoint molecules, IDO and PD-L1 are potential prognostic predictors in head and neck cancer.

The value of immunotherapy in head and neck cancer

INTRODUCTION

Head and neck squamous cell carcinomas (HNSCC) previously had limited treatment options once patients had progressed on systemic chemotherapy. With recent advances, immunotherapy now plays an important role in the treatment of advanced disease with improved outcomes as compared to cytotoxic chemotherapy.

AREAS COVERED

This article reviews the effects of the immune system and how it influences the development and response to HNSCC therapy. We additionally provide a summary of immunotherapy treatments available as well as their applicable clinical trials that led to their approval.

EXPERT COMMENTARY

The challenges that need to be addressed in order to maximize the benefits of immunotherapy in HNSCC are the selection criteria for immune checkpoint inhibitors and the optimization of combination regimens of immunotherapeutics or chemo-immunotherapy. Furthermore, there remains to be a lack of knowledge in how to incorporate molecular biomarkers as predictors of response to HNSCC immunotherapy.

PD-L1 Expression in Tumor Cells Is an Independent Unfavorable Prognostic Factor in Oral Squamous Cell Carcinoma

BACKGROUND

The immune checkpoint PD-1 and its ligand PD-L1 are involved in the induction of immunological tolerance of solid tumors including oral squamous cell carcinoma (OSCC). The aim of the study was to establish the clinical and prognostic significance of PD-L1 in OSCC.

METHODS

Tissue microarrays of 125 resected OSCC were stained with two different commercially available PD-L1 antibodies (clones E1L3N and 22C3), alongside PD-1 immunostaining.

RESULTS

PD-L1 expression in more than 10% of tumor cells was associated with poorer survival, and established as a clinically relevant cut-off point. This relevant PD-L1 expression was detected in 10% to 15% OSCC specimens depending on the anti-PD-L1 antibody, and showed an inverse correlation with tobacco and alcohol consumption. We consistently found that PD-L1 expression was associated with tumor recurrence and lower disease-specific survival. Multivariate analysis further revealed that neck node metastasis (HR 2.304; P = 0.009) and tumor PD-L1 expression (HR 2.571; P = 0.01) were significant independent factors for poor prognosis.

CONCLUSIONS

PD-L1 expression in more than 10% of tumor cells was a significant and independent factor of poor prognosis in OSCC.

IMPACT

PD-L1 expression in more than 10% of tumor cells was consistently established as a clinically relevant cut-off point by using two different antibodies. Remarkably, PD-L1 expression emerges as an independent poor prognosis marker in patients with OSCC.

High PD-L1 expression in the tumour cells did not correlate with poor prognosis of patients suffering for oral squamous cells carcinoma: A meta-analysis of the literature

OBJECTIVES

Oral cancer represents one of the most common malignancies in humans. Its prognosis is still poor, despite the most recent improvements in therapies. An increasing attention is placed on the role of programmed death ligand 1 (PD-L1) in the tumour immunity and its potential function as a marker for tumour prognosis. Whether PD-L1 expression is a prognostic factor for the poor outcomes in oral squamous cell carcinoma is still controversial. This study aimed to investigate, through a meta-analysis, a potential correlation between PD-L1 expression and the prognostic outcomes in patients with oral squamous cell carcinoma.

MATERIALS AND METHODS

The studies were identified by searching PubMed, SCOPUS, Web of Science and were assessed by two of the authors. After the selection process, 11 articles met eligibility criteria and were included in the meta-analysis. Quality assessment of studies was performed according to the REMARK guidelines, and the risk of biases across studies was investigated through Q and I² tests. Meta-analysis was performed to investigate the association between the PD-L1 expression either overall survival (OS), disease-free survival (DFS), disease-specific survival (DSS), gender and lymph node metastasis.

RESULTS

A total of 1060 patients were analysed in the 11 studies included in the meta-analysis. Pooled analysis revealed that the expression of PD-L1 did not correlate with poor OS (HR, 0.60; 95% CI: [0.33, 1.10]; P = 0.10), DFS (HR, 0.62; 95% CI: [0.21, 1.88]; P = 0.40), DSS (HR, 2.05; 95% CI: [0.53, 7.86]; P = 0.29 and lymph node metastasis (HR, 1.15; 95% CI: [0.74, 1.81]; P = 0.53). Furthermore, results of the meta-analysis showed that high expression of PD-L1 is two times more frequent in female patients (OR, 0.5; 95% CI: [0.36, 0.69]; P < 0.0001) compared to males. For all the three outcomes analysed, a high rate of heterogeneity was detected (I²  > 50%).

DISCUSSION

High PD-L1 expression did not correlate with poor prognosis of patients suffering for oral squamous cell carcinoma. Studies published on the topic showed a significant variation in results, limiting the use of PD-L1 expression by immunohistochemistry as prognostic biomarker in clinical practice.

The prognostic value of immune checkpoints in oral squamous cell carcinoma

BACKGROUND

Despite the importance of immune checkpoints in immunotherapy, the prognostic value of these molecules remains controversial in oral squamous cell carcinoma (OSCC). We performed a systematic review to investigate the prognostic significance of the immune checkpoints in OSCC.

MATERIALS

A systematic search was conducted in Ovid Medline, Scopus and Cochrane libraries, and all studies that evaluated the prognostic significance of immune checkpoints in OSCC were systematically retrieved.

RESULTS

Twelve immune checkpoints/modulators were studied for their prognostic values in OSCC patients between 1985 and 2017. Seven immune checkpoints (FKBP51, B7-H4, B7-H6, ALHD1, PD-L1, B7-H3 and IDO1) were reported to be associated with poor patients' survival in at least one study, and five (CTLA-4, TLT-2, VISTA, PD-L2 and PD-1) did not have a significant prognostic value. PD-L1 results were controversial as it was reported to be associated with both better and worse patients' survival.

CONCLUSIONS

Even though immune checkpoint markers had high expectation for OSCC prognostication, our systematic review revealed that the majority of them had been studied only once. The other molecules, which had been studied more than once, had controversial findings, except B7-H3.

Immune response and evasion mechanisms in lip carcinogenesis: An immunohistochemical study

OBJECTIVES

Programmed death ligand-1 (PD-L1) and human leukocyte antigen-G (HLA-G) are considered immune checkpoint molecules that inhibit T-cell effectiveness, contributing to tumor immune escape. This study investigated PD-L1, HLA-G, CD8, and granzyme B (GrB) expression at different stages of lip carcinogenesis.

DESIGN AND RESULTS

Forty cases of lip squamous cell carcinoma (LSCC), 55 actinic cheilitis (AC), and 10 healthy lip mucosa (HLM) were submitted to immunohistochemistry. Semiquantitative (PD-L1, HLA-G), and quantitative (CD8, GrB) analysis were performed. PD-L1 and HLA-G expression in neoplastic cells/keratinocytes and stroma/connective tissue was significantly higher in LSCC and AC, compared to HLM (p<0.05). PD-L1 was not associated with clinicopathological features of the lesions. HLA-G expression by malignant cells was significantly higher in LSCCs with distant metastasis (p = 0.041).CD8⁺ and GrB⁺ cell numbers progressively increased from HLMs to LSCC, with AC exhibiting intermediate numbers (p<0.01). Most LSCCs showed coexistence of PD-L1⁺ and CD8⁺ cells (72.5%). PD-L1 was directly correlated to CD8⁺ and GrB⁺ lymphocytic infiltration in LSCCs (p<0.05). Low cytotoxic immune response was associated with lymph node metastasis in LSCC (p<0.05).

CONCLUSIONS

PD-L1 and HLA-G-mediated immune evasion mechanisms are likely to occur from early pre-malignant to advanced malignant stages of lip carcinogenesis, which might provide a rationale for therapeutic blockade of these pathways. PD-L1 expression in LSCCs was correlated with the cytotoxic markers, suggesting that PD-L1 may appear as an escape mechanism in response to an active antitumor response.

The prognostic role of PD-L1 expression for survival in head and neck squamous cell carcinoma: A systematic review and meta-analysis

BACKGROUND

Programmed death-ligand 1 (PD-L1) is an immune checkpoint that is primarily located on the surface of tumor cells. PD-L1 expression detected by immunohistochemistry (IHC) assays has been widely studied to predict survival outcomes in head and neck squamous cell carcinoma (HNSCC) recently. We aimed to review comprehensively the prognostic role of PD-L1 expression for survival in HNSCC.

METHODS

We systematically searched PubMed, Embase, Web of Science, Cochrane Library and Scopus to identify studies investigating the prognostic role of PD-L1 expression in HNSCC. All studies published before March 31, 2018 were screened. Included studies were assessed using the Quality in Prognosis Studies (QUIPS) tool. Data were extracted and overall survival (OS), disease-free survival (DFS), progression-free survival (PFS), disease-specific survival (DSS) were combined and presented as hazard ratios (HR) with 95% confidence interval (CI) using the generic inverse-variance method.

RESULTS

Twenty-three studies with 3105 patients were analysed. The overall positive rate of PD-L1 in HNSCC was 0.42 (95% CI: 0.36-0.48). There was no significant difference between PD-L1-positive and -negative HNSCC patients in OS (HR: 0.98; 95% CI: 0.71-1.37; p = 0.93), DFS (HR: 1.07; 95% CI: 0.68-1.70; p = 0.76), and DSS (HR: 0.90; 95% CI: 0.63-1.29; p = 0.56). An improved PFS was observed in patients with positive PD-L1 expression (HR: 0.71; 95% CI: 0.55-0.93; p = 0.01). In patients with low CD8+ tumor-infiltrating T cells, a poorer OS was detected in patients with positive PD-L1 expression (HR: 1.90; 95% CI: 1.07-3.36; p = 0.03). Patients with HPV-positive HNSCC were associated with increased PD-L1 expression (OR: 1.99; 95% CI: 1.50-2.64; p < 0.001). However, PD-L1 expression showed no significant benefit on OS in HPV-positive HNSCC (HR: 1.04; 95% CI: 0.65-1.65; p = 0.88).

CONCLUSIONS

PD-L1 expression detected by IHC was not recommended to predict survival in HNSCC patients. However, the positive PD-L1 expression might predict better PFS in patients with advanced HNSCC. The combined effects of PD-L1 expression and CD8+ tumor-infiltrating T cells should be further elucidated.

PD-1 and PD-L1 expression in HNSCC primary cancer and related lymph node metastasis - impact on clinical outcome

AIMS

Expression profiles and clinical impact of programmed cell death ligand 1 (PD-L1) and programmed cell death 1 (PD-1) expressing tumour infiltrating lymphocytes (TILs) in head and neck squamous cell carcinoma (HNSCC) are not elucidated fully. This study evaluates expression patterns in primary HNSCC and related lymph node metastasis and the impact on patients' clinical outcome.

METHODS AND RESULTS

Immunohistochemical staining patterns of PD-L1 and PD-1 were evaluated in 129 specimens of primary HNSCC and 77 lymph node metastases. Results were correlated with patients' clinical data. PD-L1 expression was observed in 36% of primary carcinoma and 33% of lymph node metastasis, and correlates significantly with decreased overall survival (OS) (P = 0.01) and disease-free survival (DFS) (P = 0.001) in oral cavity squamous cell carcinoma patients. PD-L1 expression was associated with presence of lymph node metastasis (P = 0.0223). Infiltration of PD-1-expressing lymphocytes correlates significantly with favourable OS (P = 0.001) and DFS (P = 0.001) in oropharyngeal cancer and hypopharyngeal cancer patients OS (P = 0.007) and DFS (P = 0.001). Presence of PD-1 TILs also correlates significantly with better OS (P = 0.005) and DFS (P = 0) in the human papilloma virus (HPV)-negative cohort. Cox regression multivariate analysis revealed PD-1 TIL expression as an independent prognostic marker for OS (P = 0.004) and DFS (P = 0.001) and T stage was validated as negative prognostic marker for OS (P = 0.011). PD-1-expressing lymphocytes (P = 0.0412) and PD-L1 expression (P = 0.0022) patterns correlate significantly in primary cancers and matched lymph node metastases.

CONCLUSIONS

Our results characterise the expression profiles of PD-1 axis proteins in HNSCC which might serve as possible clinical prognostic markers.

Evaluating the PD-1 Axis and Immune Effector Cell Infiltration in Oropharyngeal Squamous Cell Carcinoma

PURPOSE

Programmed death-1 (PD-1) inhibitors are approved for the treatment of patients with recurrent and metastatic squamous cell carcinoma of the head and neck (SCCHN). Ongoing and planned randomized phase 3 trials are testing the benefit of combining PD-1/programmed death-ligand 1 (PD-L1) inhibitors with chemoradiation for patients with locoregionally confined SCCHN. Few studies have investigated relationships among potential predictive pathologic biomarkers such as PD-L1, PD-L2, and PD-1 in this population and associations between these markers and clinical characteristics.

METHODS AND MATERIALS

We retrospectively reviewed records and pathology from 81 patients with locoregional oropharynx SCCHN treated with curative intent. Samples were analyzed for PD-L1, PD-L2, PD-1, CD8, and CD56 expression using immunohistochemistry. Human papilloma virus (HPV) status was determined by p16-immunohistochemistry and confirmed by in situ hybridization or polymerase chain reaction-based HPV typing. Correlations between HPV status, clinical features, and recurrence status with immune markers in both tumor and tumor-associated stroma were determined. Hazard ratios were estimated via Cox proportional hazards model.

RESULTS

Tumor PD-L1 expression was inversely associated with age (P = .01) and the highest levels of expression (>30% of tumor cells) were observed in HPV-associated tumors. There was a correlation between tumor and stromal PD-L1 expression (P = < .0001). PD-1 and CD8 expression within tumor deposits was associated with HPV status (P = 0.003 and P = .008, respectively) and decreased local recurrence (P = .001 and P < .001, respectively). In addition to the association between tumor and stromal PD-1 (P < .0001), PD-1 was also correlated with tumor PD-L1 expression (P < .001). CD56+ natural killer cell infiltrates correlated with PD-L1 expression.

CONCLUSIONS

In patients with untreated oropharyngeal SCCHN, HPV-associated tumors displayed the highest levels of PD-L1 expression and PD-1+ and CD8+ immune cells. Locally recurrent tumors had lower levels of PD-L1, PD-1, and CD-8 positivity. Whereas almost all SCCHN tumors had CD56+ infiltrating natural killer cells, most tumors didn't have PD-L2 expression. These associations may help predict which patients may benefit most from immunotherapeutic approaches.

Head and neck squamous cell carcinoma: Genomics and emerging biomarkers for immunomodulatory cancer treatments

Head and neck squamous cell carcinoma (HNSCC) comprises a heterogeneous group of tumors that arise from the squamous epithelium of the oral cavity, oropharynx, larynx and hypopharynx. While many HNSCCs are related to classical etiologic factors of smoking and alcohol, a clinically, genomically, and immunologically distinct subgroup of tumors arise from the epithelium of the tonsil and the base of tongue as a result of infection with Human Papilloma Virus (HPV). In this review we describe the genomic and immunologic landscape of HNSCC, highlighting differences between HPV-positive and HPV-negative HNSCC. While HPV-negative tumors are characterized by tobacco-associated mutations in genes including TP53 and CDKN2A, in HPV-positive HNSCC integration of viral genome from HPV into the host cellular genome results in expression of the E6 and E7 viral oncoproteins, with consequent degradation of p53 and functional inactivation of Rb. The immune microenvironment of HNSCC is characterized by changes in immune cell populations, immune checkpoints, as well as tumor or microenvironmental factors that alter the balance of the immune milieu in favor of immunosuppression, allowing tumor evasion and escape from immune surveillance. Immune therapies, in particular those targeting the PD1 receptor or its ligand PD-L1, including nivolumab, pembrolizumab, durvalumab, and atezolizumab have shown significant efficacy in subsets of patients with HNSCC. Current trials are evaluating the efficacy of these agents in combination with chemotherapy, radiotherapy and other immune therapies including CTLA-4 and IDO-1 inhibitors. While biomarkers including PD-L1 expression, PD-L2 expression and the interferon-gamma gene signature show potential to predict benefit from checkpoint inhibitor therapy - it is hoped that improved understanding of the genomic and immune landscape will lead to ways to improved strategies to stratify patients and to select which HNSCC are most likely to benefit from these therapies.

Semaphorin 4D in human head and neck cancer tissue and peripheral blood: A dense fibrotic peri-tumoral stromal phenotype

The search for stromal biomarkers in carcinoma patients is a challenge in the field. Semaphorin 4D (Sema4D), known for its various developmental, physiological and pathological effects, plays a role in pro and anti-inflammatory responses. It is expressed in many epithelial tumors including head and neck squamous cell carcinoma (HNSCC). Recently, we found that HNSCC-associated Sema4D modulates an immune-suppressive, tumor-permissible environment by inducing the expansion of myeloid derived suppressor cells. The purpose of this study was to determine the value of Sema4D as a biomarker for the peri-tumoral stromal phenotype in human HNSCC. Our data showed Sema4D^+ve/high tumor cells in 34% of the studied cohort with positive correlation to Stage III (p=0.0001). Sema4D^+ve/high tumor cells correlated directly with dense fibrotic peri-tumoral stroma (p=0.0001) and inversely with infiltrate of Sema4D^+ve/high tumor-associated inflammatory cells (TAIs) (p=0.01). Most of the Sema4D^+ve/high TAIs were co-positive for the macrophage biomarker CD163. Knockdown of Sema4D in WSU-HN6 cells inhibited collagen production by fibroblasts, and decreased activated TGF-β1 levels in culture medium of HNSCC cell lines. In a stratification model of HNSCC using combined Sema4D and the programmed death ligand 1 (PDL-1), Sema4D^+ve/high tumor cells represented a phenotype distinct from the PDL-1 positive tumors. Finally,Sema4D was detected in plasma of HNC patients at significantly higher levels (115.44, ± 39.37) compared to healthy donors (38.60± 12.73) (p <0.0001). In conclusion, we present a novel HNSCC tumor stratification model, based on the expression of the biomarker Sema4D. This model opens new avenues to novel targeted therapeutic strategies.

Significance of PD-L1 Expression in Tongue Cancer Development

Aims: Immunohistochemistry of PD-L1 has been recently established as a surrogate method to predict if immunotherapy targeting PD-L1/PD-1 has a significant effect on suppression of cancers such as lung non-small cell carcinoma, melanoma, and renal cell carcinoma. Here we performed immunohistochemistry for PD-L1 expression in squamous cell carcinoma (SCC) of the tongue to investigate the potential correlation between PD-L1 expression and clinicopathological factors and whether PD-L1 expression would be associated with prognosis. Methods: Tissue microarray cores of paraffin-embedded blocks from 135 cases with surgically resected tongue SCC were immunohistochemically analysed for PD-L1 expression. Results: We observed a positive correlation between PD-L1 expression and tongue SCC pT1 and pT2 tumours, but a negative correlation with pT2, pT3 and pT4 tumours. We also observed a positive correlation with lymph node metastasis. However, no positive correlation was demonstrated between PD-L1 expression and overall survival. Conclusions: PD-L1 tends to be overexpressed at the early stage of tongue SCC, showing a close correlation with initial development of tongue. However, PD-L1 expression may not affect prognosis.

PD-L1 expression in tumor tissue and peripheral blood of patients with oral squamous cell carcinoma

Background

Immune checkpoints like programmed cell death-1 (PD-1) and its ligand PD-L1 are involved in immune escape mechanisms of solid tumors including oral squamous cell carcinoma (OSCC). Inhibitors of the pathway are successfully used for treating especially advanced disease. However, the physiological relevance of PD-1/PD-L1-signaling in OSCC is insufficiently understood. The aim of the study was to analyze if PD-L1 expression in tumor tissue and peripheral blood samples of OSCC patients is associated with histomorphological tumor parameters and if PD-L1 expression in patients is different from controls.

Results

OSCC tumor specimens showed a significantly higher PD-L1 expression than oral mucosa controls (p < 0.001; upregulation more than 3-fold). Cross-tabulation revealed an association of increased expression of PD-L1 mRNA in tissue specimens with malignancy (p < 0.001).

OSCC cases with higher tumor grade and cases with lymph node metastases (N+) were significantly (p < 0.05) associated with increased PD-L1 expression in peripheral blood. Cross-tabulation revealed an significant association with lymph node metastases (N+) (p ≤ 0.002).

Materials and Methods

PD-L1 mRNA expression was analyzed in tumor specimens and corresponding samples of healthy oral mucosa and peripheral blood of 45 OSCC patients and 36 healthy control persons using RT-qPCR analysis. A Mann-Whitney U-test, a cut-off point analysis and a Chi-square test were carried out.

Conclusions

PD-L1 expression in OSCC could contribute to the immunosuppressive local tumor microenvironment. Increased malignant behavior (higher tumor grade, positive nodal status) might be associated with PD-L1 mediated systemic immune tolerance. Thus, PD-L1 expression in peripheral blood might be an indicator of the existence of metastatic disease (N+) in OSCC.

Two immune-enhanced molecular subtypes differ in inflammation, checkpoint signaling and outcome of advanced head and neck squamous cell carcinoma

The immune environment of primary tumor is associated with the clinical response and benefit of immunotherapy. This study aims to investigate the intratumoral immune profile and its clinical relevance in advanced head and neck squamous cell carcinoma (HNSCC). Gene expression profiles of 401 HNSCCs at stage III-IVB from two cohorts (The Cancer Genome Atlas, TCGA, n = 203; the Leipzig Head and Neck Group, LHNG, n = 198) were involved in this analysis. Based on the global immune-related genes, four gene expression subtypes (C1-4) were identified in HNSCCs. Overall, subtypes C2 and C3 showed upregulation of immune profiles and increased tumor lymphocyte infiltration, exhibiting an enhanced immune microenvironment (EIME). However, the two EIME subtypes revealed differences in immune markers and clinical features. Subtype C2 showed higher expression of macrophage signature, whereas subtype C3 was more associated with B cell infiltration. T cell and NK cell infiltration was not different between C2 and C3 subtypes. The subtype C2 tumors were characterized by inflammation compared with subtype C3. Although the checkpoint receptors PD1 and CTLA4 expressed equally between the EIME subtypes, their ligands (PD-L1/PD-L2, CD86/CD80) were significantly upregulated in subtype C2 compared with C3. HPV-positive tumors were predominantly enriched in subtype C3 but not in C2. Furthermore, patients in subtype C2 had a worse outcome than those in C3. In summary, two immune-enhanced subtypes with different immune characteristics and clinical features were identified in advanced HNSCC. The different immune microenvironments among HNSCC subgroups may provide new insights into the strategy of immunotherapy.

Circulating tumour cell PD-L1 test for head and neck cancers

Immune checkpoint inhibitors have gained traction over the last few years in the treatment of metastatic/recurrent head and neck squamous cell carcinoma (HNSCC) patients. Monoclonal antibodies that block the programmed death 1 (PD-1) receptor and its major ligand, PD-L1, have shown durable responses and low toxicity profiles. There are currently no validated predictive biomarkers to select patients likely to respond to anti-PD-1/PD-L1 therapy to avoid unwanted side effects and to reduce healthcare expenditure. A circulating tumour cell (CTC) PD-L1 assay could be developed as a companion diagnostic tool to potentially predict the efficacy of immune checkpoint blockade treatments.

Prognostic Stratification of Patients With Advanced Oral Cavity Squamous Cell Carcinoma

PURPOSE OF REVIEW

Prognosis of advanced oral squamous cell carcinoma remains a challenge for clinicians despite progress in its diagnosis and treatment over the past decades. In this review, we assessed clinicopathological factors and potential biomarkers along with their prognostic relevance in an attempt to develop optimal treatment strategies for these patients.

RECENT FINDINGS

In addition to several pathologic factors that have been proposed to improve prognostic stratification and treatment planning in the eighth edition of the American Joint Committee staging manual on cancer, we reviewed some other imaging and clinicopathological parameters demonstrated to be closely associated with patient prognosis, along with the biomarkers related to novel target or immune therapy. Evaluation of current literature regarding the prognostic stratification used in contemporary clinicopathological studies and progress in the development of targeted or immune therapy may help these patients benefit from tailored and personalized treatment and obtain better oncological results.