Expression of PD-L1 on Immune Cells Shows Better Prognosis in Laryngeal, Oropharygeal, and Hypopharyngeal Cancer

Prognostic Significance of the Microenvironment in Human Papillomavirus Oropharyngeal Carcinoma: A Systematic Review

OBJECTIVE

The immune microenvironment of HPV-associated (HPV+) oropharyngeal squamous cell carcinomas (OPSCCs) (HPV+OPSCCs) differs from that of HPV-independent oropharyngeal cancers (HPV-independent OPSCCs). The literature on the subject is very abundant, demanding an organized synthesis of this wealth of information to evaluate the hypothesis associating the favorable prognosis of HPV+OPSCC patients with a different immune microenvironment. A systematic review of the literature was conducted regarding the microenvironment of HPV+OPSCCs.

DATA SOURCE

MEDLINE/PubMed, Embase, and Cochrane Library databases.

REVIEW METHODS

A literature search was performed following PRISMA guidelines (Moher D. PLoS Med. 2009). The PEO (Population, Exposure, and Outcome) framework is detailed as follows: P: patients with oropharyngeal squamous cell carcinomas, E: human papillomavirus (HPV), and O: histological and immunological composition of the tumoral microenvironment (TME). No meta-analysis was performed.

RESULTS

From 1,202 studies that were screened, 58 studies were included (n = 6,474 patients; n = 3,581 (55%) HPV+OPSCCs and n = 2,861(45%) HPV-independent OPSCCs). The presence of tumor-infiltrating lymphocytes (TIL), CD3+ in 1,733 patients, CD4+ in 520 patients, and CD8+ (cytotoxic T lymphocytes (CTL)) in 3,104 patients, and high levels of PD-L1 expression in 1,222 patients is strongly correlated with an improved clinical outcome in HPV+OPSCCs.

CONCLUSION

This systematic review provides the most comprehensive information on the immune microenvironment of HPV+OPSCCs to date. Tumor-infiltrating lymphocytes and PD-L1 expression are associated with a favorable prognosis. B, CD8+ and resident memory cells densities are higher in HPV+OPSCCs. The importance of myeloid lineages is still a matter of debate and research.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:1507-1516, 2024.

Programmed death-ligand 1 and tumor-infiltrating lymphocytes (TILs) - low TIL density may predict poorer long-term prognosis in T1 laryngeal cancer

We evaluated the prognostic role of programmed death-ligand 1 (PD-L1) and tumor-infiltrating lymphocytes (TILs) in T1 glottic laryngeal squamous cell carcinoma (LSCC). T1 glottic LSCC patients (n = 174) treated at five Finnish university hospitals between 2003 and 2013 were included. Tissue microarray (TMA) blocks were used for PD-L1 immunohistochemistry. TILs were scored from intratumoral and stromal regions in whole tissue sections. Of 174 patients, 92 (53%) had negative, 66 (38%) intermediate, and 16 (9%) high PD-L1 levels. Of 80 patients whose TILs were analyzed, 50 (63%) had low and 30 (38%) high stromal TIL density. Patients with a local recurrence or a new primary tumor of the larynx had lower TIL density than had other patients (p = 0.047). High PD-L1 expression with low stromal TIL density was associated with inferior 5-year disease-specific survival (85% vs. 100%, p = 0.02). In conclusion, in patients treated for T1 glottic LSCC, low stromal TIL density was associated with local recurrences and new primary tumors of the larynx. High PD-L1 expression with low stromal TIL density may be associated with worse survival in T1 glottic LSCC.

The Histological Background of Recurrence in Laryngeal Squamous Cell Carcinoma: An Insight into the Modifications of Tumor Microenvironment

Recurrent laryngeal carcinoma presents differences from the primary tumor that largely depend on the treatment. In this article, we review the histologic and molecular treatment-induced changes that may affect the diagnosis of recurrent laryngeal carcinoma, the assessment of predictive markers, and the response to treatment with immune checkpoint inhibitors. Radiotherapy induces profound modifications that are strictly related to necrosis of different tissue components, fibrosis, and damage of the tumor vessels. Postradiotherapy recurrent/persistent laryngeal squamous cell carcinoma typically presents a discohesive growth pattern within a fibrotic background associated with significant changes of the tumor immune microenvironment, with both important immunosuppressive and immunostimulatory effects. Overall, the increase of immunoregulatory cells and immune checkpoints such as CTLA-4, TIM-3, PD-1, and PD-L1 induced by radiotherapy and chemotherapy strongly supports the use of immune checkpoint inhibitors in recurrent/persistent laryngeal carcinoma. Future studies aiming to identify predictive factors of the response to immune checkpoint inhibitors should consider such treatment-induced modifications.

Clinical significance of overall assessment of tumor-infiltrating lymphocytes in oropharyngeal cancer: A meta-analysis

BACKGROUND

The overall assessment of tumor-infiltrating lymphocytes (TILs) evaluated using hematoxylin and eosin (HE) staining has been recently studied in oropharyngeal squamous cell carcinoma (OPSCC).

METHODS

We conducted a systematic review of Scopus, Ovid Medline, PubMed, Web of Science, and Cochrane Library to retrieve studies assessing TILs in HE-stained sections of OPSCC. We used fixed-effect models and random-effect models to estimate the pooled hazard ratios (HRs) and confidence intervals (CIs) for disease-free survival (DFS), overall survival (OS) and disease-specific survival (DSS).

RESULTS

Eleven studies were identified that had analyzed the prognostic significance of TILs in OPSCC using HE-stained specimens. Our meta-analyses showed that a high infiltration of TILs was significantly associated with improved DFS (HR 0.39, 95%CI 0.24-0.65, P = 0.0003), OS (HR 0.38, 95%CI 0.29-0.50, P < 0.0001), and DSS (HR 0.32, 95%CI 0.19-0.53, P < 0.0001).

CONCLUSION

Findings of our meta-analysis support a growing body of evidence indicating that assessment of TILs in OPSCC using HE-stained sections has reliable prognostic value. The clinical significance of such assessment of TILs has been reported repeatedly in many studies on OPSCC. The assessment is cost-effective, feasible, easy to transfer from lab to clinic, and therefore can be incorporated in daily practice.

Prognostic value of PD-1, PD-L1 and PD-L2 deserves attention in head and neck cancer

Head and neck cancer has high heterogeneity with poor prognosis, and emerging researches have been focusing on the prognostic markers of head and neck cancer. PD-L1 expression is an important basis for strategies of immunosuppressive treatment, but whether it has prognostic value is still controversial. Although meta-analysis on PD-L1 expression versus head and neck cancer prognosis has been performed, the conclusions are controversial. Since PD-L1 and PD-L2 are two receptors for PD-1, here we summarize and analyze the different prognostic values of PD-1, PD-L1, and PD-L2 in head and neck cancer in the context of different cell types, tissue localization and protein forms. We propose that for head and neck cancer, the risk warning value of PD-1/PD-L1 expression in precancerous lesions is worthy of attention, and the prognostic value of PD-L1 expression at different subcellular levels as well as the judgment convenience of prognostic value of PD-1, PD-L1, PD-L2 should be fully considered. The PD-L1 evaluation systems established based on immune checkpoint inhibitors (ICIs) are not fully suitable for the evaluation of PD-L1 prognosis in head and neck cancer. It is necessary to establish a new PD-L1 evaluation system based on the prognosis for further explorations. The prognostic value of PD-L1, PD-L2 expression in head and neck cancer may be different for early-stage and late-stage samples, and further stratification is required.

Association of immune response with overall and disease-free survival in laryngeal squamous cell carcinomas

OBJECTIVES

This study aimed to examine the relationship between checkpoint receptors (PD-1, PD-L1, PD-L2, CTLA-4) and lymphoid infiltration level (TILs) with prognostic features of patients with laryngeal squamous cell carcinoma (LSCC).

METHODS

A retrospective study was designed at a tertiary referential university hospital between April 2008 and December 2020. The surgical specimen of the patients who met the eligibility criteria were re-examined histopathological, sociodemographic, clinical, pathological, and follow-up findings of patients were determined. The impact of PD-1, PD-L1, PD-L2, CTLA4, and TILs levels for the presence of cancer recurrence, disease-specific mortality, overall survival (OS), disease-free survival (DFS) was investigated.

RESULTS

Forty-five patients with LSCC were included in the study. The mean follow-up period was 48.3 ± 14.3 months (min: 36, max 84). TILs scores were detected significantly lower in patients with distant metastasis and recurrence (p = 0.046 and 0.010). Also, only TILs was a significant risk factor for recurrence and survival among the PD-1, PD-L1, PD-L2, CTLA-4, and TILs (HR = 0.217 CI: 0.070-0.679, p = 0.009 and HR = 0.566, CI: 0,321-980, p = 0.048). Similarly, for the TILs score: > 1 was significant for DFS. (Long-Rank = 0.009). The examined markers and TILs scores were not a significant predictive factor for OS.

CONCLUSION

An increase in TILs density in LSCCs is associated with a better prognosis. However, PD-1, PD-L1, PD-L2, CTLA-4 could not be associated with prognosis. Controlled studies combined with immunotherapy treatment results are needed to reveal their role as a marker and prognostic factor of the anti-tumor immune response.

Tissue and circulating PD-L2: moving from health and immune-mediated diseases to head and neck oncology

Amongst the chief targets of immune-checkpoint inhibitors (ICIs), namely the Programmed cell death protein 1 (PD-1)/PD-Ligands (Ls) axis, most research has focused on PD-L1, while to date PD-L2 is still under-investigated. However, emerging data support PD-L2 relevant expression in malignancies of the head and neck area, mostly in head and neck squamous cell carcinoma (HNSCC) and salivary gland cancers (SGCs). In this context, ICIs have achieved highly heterogeneous outcomes, emphasizing an urgent need for the identification of predictive biomarkers. With the present review, we aimed at describing PD-L2 biological significance by focusing on its tissue expression, its binding to PD-1 and RGMb receptors, and its impact on physiological and anti-cancer immune response. Specifically, we reported PD-L2 expression rates and significant clinical correlates among different head and neck cancer histotypes. Finally, we described the biology of soluble PD-L2 form and its potential application as a prognostic and/or predictive circulating biomarker.

Effect of Programmed Death-Ligand 1 in Cancer-Associated Fibroblasts on Advanced Laryngeal Squamous Cell Carcinoma

This study aimed to explore the effect of programmed death-ligand 1 (PD-L1) in cancer-associated fibroblasts (CAFs) on advanced laryngeal squamous cell carcinoma (LSCC). The expression of PD-L1 in advanced LSCC tumor tissues was observed in 83 patients with LSCC by immunofluorescence microscopy and compared with that in normal laryngeal mucosa. The CAFs of LSCC and normal fibroblasts (NFs) were isolated, cultured, purified, and examined by fluorescence. The expression of PD-L1 in purified CAFs and NFs was measured by flow cytometry. The expression of PD-L1 in CAFs was downregulated through small interferring RNA (siRNA) transfection. The proliferation and migration capacities of CAFs were observed using proliferation and scratch tests, respectively. The proliferation of HEP-2 cells and T cells was measured after cocultured with CAFs. The secretion of interleukins IL-2 and IL-10 was detected using enzyme-linked immuno sorbent assay (ELISA). PD-L1 was expressed in 62 of 83 cases of the advanced LSCC tumor tissues. Also, CAFs expressed more PD-L1 compared with NFs. The proliferation and migration capacities of CAFs were significantly lower after transfection with PD-L1-siRNA. The proliferation rate of HEP-2 cells cocultured with CAFs decreased in PD-L1-siRNA-transfected cells. However, the proliferation rate of T cells increased in transfected cells. The ELISA results showed that the secretion of IL-2 increased and that of IL-10 decreased in PD-L1-siRNA-transfected cells. The expression of PD-L1 in CAFs of advanced LSCC was higher than that in NFs. The downregulation of PD-L1 reduced the proliferation and migration of CAFs and HEP-2 cells but enhanced the proliferation and pro-inflammatory function of T cells in the coculture experiment.

Expression of Programmed Death Receptor 1 (PD-1) Gene and Its Ligand (PD-L1) in Patients with Laryngeal Cancer

(1) Background: The interaction of the programmed death receptor (PD-1) with its ligand 1 (PD-L1) allows cancer cells to escape from the control of the immune system. Research evaluating the expression of immune checkpoint genes in the tissues of laryngeal tumors may contribute to the introduction of new effective immunotherapeutic methods in this group of neoplasms. The aim of this study was to evaluate the expression of the gene for the programmed death receptor (PD-1) and its ligand (PD-L1) in laryngeal tumors (T1, T2, T3) in patients without lymph node involvement and distant metastases. (2) Methods: The study included 73 patients: 39 of them were diagnosed with carcinoma planoepiteliale keratodes (study group) and 34 with nasal septal deviation undergoing septoplasty (control group). Biological material for molecular tests (Real time PCR) was collected during surgical procedures. Furthermore, all study participants completed a questionnaire regarding, among others, smoking and body weight. (3) Results: Gene expression for programmed death receptor 1 (PD-1) and its ligand 1 (PD-L1) was, statistically, significantly higher (p < 0.0001) in tumor tissue than in unchanged mucosa. Moreover, it was found that the greater the tumor size, the higher the expression level of the tested molecules. (4) Conclusions: Although further research on the role of the PD-1/PD-L1 pathway in laryngeal tumors is necessary, the presented reports are promising and may constitute a contribution to considerations on the introduction of targeted immunotherapy with anti-PD1 and anti-PD-L1 monoclonal antibodies in the treatment of these tumors.

Tumor-Infiltrating Lymphocytes in the Tumor Microenvironment of Laryngeal Squamous Cell Carcinoma: Systematic Review and Meta-Analysis

The presence of tumor-infiltrating lymphocytes (TIL) in the tumor microenvironment has been demonstrated to be of prognostic value in various cancers. In this systematic review and meta-analysis, we investigated the prognostic value of TIL in laryngeal squamous cell carcinoma (LSCC). We performed a systematic search in PubMed for publications that investigated the prognostic value of TIL in LSCC. A meta-analysis was performed including all studies assessing the association between TIL counts in hematoxylin-eosin (HE)-stained sections, for CD8+ and/or CD3+/CD4+ TIL and overall survival (OS) or disease-free survival (DFS). The pooled meta-analysis showed a favorable prognostic role for stromal TIL in HE sections for OS (HR 0.57, 95% CI 0.36–0.91, p = 0.02), and for DFS (HR 0.56, 95% CI 0.34–0.94, p = 0.03). High CD8+ TIL were associated with a prolonged OS (HR 0.62, 95% CI 0.4–0.97, p = 0.04) and DFS (HR 0.73, 95% CI 0.34–0.94, p = 0.002). High CD3+/CD4+ TIL demonstrated improved OS (HR 0.32, 95% CI 0.16–0.9, p = 0.03) and DFS (HR 0.23, 95% CI 0.10–0.53, p = 0.0005). This meta-analysis confirmed the favorable prognostic significance of TIL in LSCC. High stromal TIL evaluated in HE sections and intra-tumoral and stromal CD3+, CD4+ and/or CD8+ TIL might predict a better clinical outcome.

Low PDL1 Expression in Tumour Infiltrating Lymphocytes Predicts Local Recurrence in Oral Squamous Cell Carcinoma

In oral squamous cell carcinoma (OSCC), expression of PDL1 is controversial with expressions showing a positive and negative correlation with survival in previous studies. Additionally, it is unclear whether expression on the tumour or tumour infiltrating lymphocytes (TIL) is a better predictor of survival. We performed this study on a cohort of Indian patients with OSCC to determine impact of PDL1 expression on survival. Retrospective analysis of 64 patients of OSCC treated with curative intent surgery with or without adjuvant therapy was performed. Stored tissue blocks were extracted and quantitative immunohistochemistry was performed for PDL1 expression separately on the tumour and the TIL using commercially available Dako kits. Correlation of clinical and pathological variables with PDL1 expression was performed using chi-square test. Survival analysis was performed using Kaplan-Meier method and Cox proportional hazards ratio. In our cohort, PDL1 expression was low, both in tumour (92% had <1% expression) and TIL (56% had <1% expression). Tumour low PDL1 expression (<1%) was associated with a higher risk of lymphovascular invasion (p = 0.044) and bone invasion (p = 0.01) but did not impact survival. Low TIL PDL1 expression (<1%) was more common in younger patients (<45 years) (p = 0.023) significantly predicting local recurrence (p = 0.02). PDL1 expression in OSCC was low. Low TIL PDL1 was common in younger patients and predicted local recurrence. Further study is required to better understand the relationship between age, tumour microenvironment and local recurrence.

Laryngeal Squamous Cell Carcinoma: Potential Molecular Mechanism and Prognostic Signature Based on Immune-Related Genes

BACKGROUND Immune-related genes (IRGs) are closely related to the incidence and progression of tumors, potentially indicating that IRGs play an important role in laryngeal squamous cell carcinoma (LSCC). MATERIAL AND METHODS An RNA sequencing dataset containing 123 samples was collected from The Cancer Genome Atlas. Based on immune-related differentially expressed genes (IRDEGs), a potential molecular mechanism of LSCC was explored through analysis of information in the Gene Ontology (GO) resource and the Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein-protein interactions (PPIs). A regulatory network of transcriptional regulators and IRDEGs was constructed to explore the underlying molecular mechanism of LSCC at the upstream level. Candidates from IRDEGs for signature were screened via univariate Cox analysis and using the least absolute shrinkage and selection operator (LASSO) technique. The IRDEG signature of LSCC was constructed by using a multivariate Cox proportional hazards model. RESULTS GO and KEGG analysis showed that IRDEGs may participate in the progression of LSCC through immune-related reactions. PPI analysis demonstrated that, among the IRDEGs in LSCC, the Kininogen 1; C-X-X motif chemokine ligand 10; elastase, neutrophil expressed; and LYZ genes are hub genes in the development of LSCC. At the upstream level, SPI1, SP140, signal transducer and activator of transcription 4, zinc finger E-box binding homeobox, and Ikaros family zinc finger 2 are the hub transcriptional regulators of IRDEGs. The risk score based on the IRDEG signature was able to distinguish prognosis in patients with LSCC and represents an independent prognostic risk factor for LSCC. CONCLUSIONS From the perspective of IRGs, we first constructed an IRDEG signature related to the prognosis of LSCC, which can be used as a novel marker to predict prognosis in patients with LSCC.

PD-L1 in Combination with CD8+TIL and HIF-1α are Promising Prognosis Predictors of Head and Neck Squamous Cell Carcinoma

Objective

The aim of this study was to evaluate the prognosis effect of PD-L1 in combination with CD8⁺ tumor-infiltrating lymphocyte (TIL) or HIF-1α in head and neck squamous cell carcinoma (HNSCC).

Methods

A total of 63 patients who underwent surgical resection were included in this study. The level of PD-L1, CD8⁺ TIL, and HIF-1α was determined by immunohistochemical analysis. The survival of patients was evaluated by Kaplan–Meier analysis. The prognostic power of these parameters was evaluated by C-index.

Results

We observed that the survival of patients, who had a high level of PD-L1 in tumor cells, was significantly shorter than those who had a low level of PD-L1. However, the survival of patients who had a high level of PD-L1 in tumor microenvironment was significantly longer than patients with a low level of PD-L1 in tumor microenvironment. In addition, high level of CD8⁺ tumor-infiltrating lymphocyte or low level of HIF-1α level suggests a better prognosis. Moreover, we observed that PD-L1 in combination with CD8⁺ tumor-infiltrating lymphocyte and HIF-1α could significantly improve the prognostic effect of current TNM stage.

Conclusion

The results of this study suggest that the level of PD-L1, CD8⁺TIL, and HIF-1α are useful prognostic biomarkers for patients with HNSCC. Incorporating these biomarkers into current TNM stage of HNSCC improve the discriminatory capability of TNM stage.

Programmed Death Ligand 1 Expression in Laryngeal Squamous Cell Carcinomas and Prognosis

Aim

We aimed to show the immunohistochemical expression of programmed death ligand 1 (PD-L1) in laryngeal squamous cell carcinomas (SCCs).

Materials and methods

The study includes 52 laryngeal SCC cases that underwent surgical resection. Immunohistochemical staining of PD-L1 (Clone 22C3) was applied to the sections obtained from paraffin blocks. Combined Positive Score (CPS) was evaluated as described in manuals. Tumor Proportion Score (TPS) was assessed by the percentage of positive tumor cells which were designated as positive if ⩾1% of the tumor cells showed membranous staining.

Results

There were 35 cases (67.3%) having CPS < 1 and 17 cases (32.7%) having CPS ⩾ 1. There was no relationship between CPS, TPS, and the clinicopathological data.

Conclusion

Further studies with a large number of advanced-stage cases are needed.

Prognostic impact of neutrophils-to-lymphocytes ratio (NLR), PD-L1 expression, and tumor immune microenvironment in laryngeal cancer

PURPOSE

In laryngeal carcinoma (LSCC), tumor immune microenvironment is attracting increasing interest, given the recent progresses in immunotherapy. Immune cells migrate to tumors as a result of a tumor antigen-induced immune reaction and cancer cells recruit immune regulatory cells to induce an immunosuppressive network, resulting in the escape from host immunity. This interaction reflects both on tumor microenvironment and systemic inflammatory status. Blood neutrophil-to-lymphocyte ratio (NLR), reflecting a highly pro-inflammatory status, has been related to worse oncological survival outcomes. The aim of this study was to analyze in LSCC the relationship between circulating inflammatory cells (also in terms of NLR) and tumor immune microenvironment histopathological features (programmed cell death ligand 1 [PD-L1] expression, and tumor-infiltrating lymphocytes [TILs]), also investigating their clinical-pathological and prognostic significance.

METHODS

Blood pre-operative NLR, and, at pathology, PD-L1 (in terms of combined positive score [CPS]) and TILs were assessed on 60 consecutive cases of LSCC.

RESULTS

Blood NLR, neutrophils, and lymphocytes counts showed a significant value in predicting DFS and recurrence risk. Moreover, PD-L1 CPS ≥ 1 and TILs count rate ≥30% were associated with higher disease-free survival (DFS) and reduced recurrence risk. A logistic regression model found a significant positive association between increasing NLR values, and PD-L1 CPS < 1 and TILs count rate <30%.

CONCLUSIONS

Further studies are needed to better characterize the role of pre-operative blood NLR in association with PD-L1 expression and tumor immune microenvironment features as prognostic factors and markers of anti-tumor immune response in LSCCs, also with regard to the effectiveness of immunotherapeutic protocols.

Biological Function of PD-L2 and Correlation With Overall Survival in Type II Endometrial Cancer

In cancer, upregulation of coinhibitory B7 ligands has been associated with immune evasion. So far, anti-programmed death-1 (PD-1) and anti-PD-ligand 1 (PD-L1) antibodies have been used in immuno-oncology, with promising outcomes; however, it is still needed to identify other markers, especially for endometrial cancer (EC). EC is a gynecological malignancy historically classified into two types: type I, with mostly estrogen-dependent endometrioid diseases, and the most aggressive type II, including mainly estrogen-independent and non-endometrioid tumors. PD ligand-2 (PD-L2) is known as the second ligand of the PD-1 receptor and, upon its binding, contributes to T-cell exhaustion. Up to now, very few information are available about PD-L2 in cancers, and no data have been reported for EC. The aim of this work was to characterize the PD-L1 and PD-L2 ligand expression profile in EC cell lines, focusing the attention on the biological role of PD-L2 and its prognostic impact in human type II EC biopsies. Using in silico analysis of TCGA data, we performed a molecular profiling in a cohort of 506 patients, both types I and II, and PD-1 ligands expression was also analyzed in different primary human EC cell lines. Moreover, PD-L2 staining was evaluated in a cohort of human type II EC samples and correlated with the overall survival (OS), progression-free survival (PFS), and additional clinicopathological data. From the in silico analysis, PD-L2 was more expressed than PD-L1 in EC cell lines. PD-L2 was found highly expressed in 64.44% of tumor specimens, predominantly in the serous subtype, in both stromal and epithelial components, while in peritumoral and normal tissues it was predominantly moderate or low. In vitro, we investigated the cell autonomous role of PD-L2 in controlling cell survival, migration, and chemoresistance.

Emerging role of immune checkpoint inhibitors and predictive biomarkers in head and neck cancers

Head and neck cancers are a group of diverse and heterogeneous tumors, among which squamous cell carcinoma of the head and neck (SCCHN) is the most prevalent. Current treatment modalities have limited efficacy; therefore, new therapies are being actively developed and evaluated. The introduction of immune checkpoint inhibitors (ICIs) has led to a paradigm shift in the management of difficult-to-treat malignancies. In this review, we summarize recent advances in the development of immunotherapies, which are aimed at the functional restoration of the immune system to counteract immune-evasion strategies of cancer cells, and related biomarkers. Monotherapies with ICIs, which primarily target the programmed cell death-1 (PD-1) pathway, have shown promising results in clinical trials of patients with recurrent and metastatic SCCHN. Combinations of ICIs with conventional or virus therapies often have synergistic therapeutic effects, without increased toxicity. As only a small subset of patients respond to immunotherapy, biomarkers are essential for the prediction of treatment response and better selection of patients for ICIs. PD-1 ligand (PD-L1) expression is correlated with response but has several limitations as a predictive marker, as its expression is dynamic and heterogeneous, and the cut-off needs further confirmation. Therefore, tumor mutation burden, gene expression signatures, microsatellite instability, tumor-infiltrating lymphocytes, viral antigens, and the oral microbiota are being investigated as predictive biomarkers. Finally, we delineate other challenges and future prospects for improving patient outcomes, including the major challenge of identifying and validating predictive biomarkers that need to be addressed in future studies.

Prognostic Significance of PD-L1 Expression and Its Tumor-Intrinsic Functions in Hypopharyngeal Squamous Cell Carcinoma

Purpose

The expression of programmed death-ligand 1 (PD-L1) is common in various solid human cancers and it is an important therapeutic target. However, the expression pattern, clinical significance and potential mechanism of PD-L1 in hypopharyngeal squamous cell carcinoma (HSCC) are still lacking.

Methods

PD-L1 expression in HSCC tumor tissues and paired adjacent hypopharyngeal mucosal tissues was detected using immunohistochemistry assay, and the clinical significance of PD-L1 in HSCC was characterized. In vitro assays including cell viability assays, migration assays, invasion assays as well as Western blot assays were performed to illuminate the biological functions and underlying molecular mechanisms of PD-L1 in HSCC development.

Results

PD-L1 expression was detected in HSCC samples but we found no positive expression in matched normal hypopharyngeal mucosal tissues. The levels of PD-L1 expression were significantly correlated with advanced clinical progression and poor patient survival. Multivariable analysis of Cox model showed that PD-L1 expression was an independent predictor for the prognosis of HSCC patients. Functional experiments showed that the ectopic expression of PD-L1 markedly influenced the proliferation, migration and invasion of FaDu cells in vitro. Mechanistically, investigations demonstrated that PD-L1 could promote the epithelial–mesenchymal transition of FaDu cells. Meanwhile, PD-L1 knockdown inhibited, while PD-L1 overexpression activated the Akt-mTOR signaling pathway in FaDu cells. The EMT induced by PD-L1 overexpression could be reversed by the Akt inhibitor.

Conclusion

In summary, the expression of PD-L1 can act as a significant biomarker for the adverse clinicopathological features and poor prognosis of patients with HSCC. PD-L1 can promote the proliferation, migration and invasion of FaDu cells and consequently enhance the aggressiveness. Moreover, PD-L1 induces EMT through AKT-mTOR signaling pathway. These suggest that PD-L1 has important tumor-intrinsic functions independent of its immunopathogenic effects.

Postoperative radiotherapy for laryngeal cancer. The prognostic role of programmed death-ligand 1: An immune microenvironment-based cluster analysis

BACKGROUND

The prognostic role of programmed death-ligand 1 (PD-L1) expression and the tumor's immune microenvironment has yet to be investigated in the specific setting of adjuvant postoperative radiotherapy (PORT) for laryngeal carcinoma (LSCC). The main aim of this exploratory study was to investigate, also by cluster analysis, whether PD-L1 expression (in terms of combined positive score [CPS]), tumor-infiltrating lymphocytes (TIL), and tertiary lymphoid structures (TLS) correlated prognostically with response to PORT in a cohort of consecutive LSCC patients.

METHODS

PD-L1, TIL and TLS were assessed in 24 consecutive patients with LSCC who underwent PORT. Cluster analysis was used to classify cases on the strength of these parameters.

RESULTS

A CPS ≥ 1 was associated with a significantly lower recurrence rate (p = 0.033), and longer disease-free survival (DFS) (p = 0.012) than a CPS < 1. Two clusters of prognostic relevance emerged from our analysis. Cluster 1 was characterized by a mean CPS of 23.0 ± 37.9, a mean TIL count of 68.0 ± 16.4, and the presence of TLS in all cases. Cluster 2 featured a mean CPS of 3.1 ± 7.3, a mean TIL count of 23.9 ± 16.5, and no cases with TLS. Cluster 1 showed a trend towards a lower recurrence rate (p = 0.071) and longer DFS (p = 0.054) than cluster 2.

CONCLUSIONS

Judging from this preliminary investigation, assessing PD-L1 and immune microenvironment markers seems a promising approach for identifying patients at higher risk of LSCC recurrence after PORT, who might reasonably benefit from adjuvant postoperative chemo-RT, or immunotherapy.

Immune related proteins and tumor infiltrating CD8+ lymphocytes in hypopharyngeal cancer in relation to human papillomavirus (HPV) and clinical outcome

BACKGROUND

Hypopharyngeal cancer (HPSCC) shows a poor clinical outcome, while HPSCC, caused by human papillomavirus (HPV), presents a better outcome. Here, HPCC, immune proteins, and tumor infiltrating CD8+ lymphocytes (CD8+ TILs) were evaluated in relation to HPV and outcome.

METHODS

Fresh frozen tissue from four HPV-positive HPSCC, 39 HPV-negative HPSCC, and normal samples were analyzed for protein expression by the Proseek immuno-oncology immunoassay. CD8+ TIL numbers evaluated by immunohistochemistry on 144 formalin-fixed biopsies were analyzed in relation to clinical outcome.

RESULTS

Proteins differing between HPV-positive and negative HPSCC included CD8A, PD-L1, Fas ligand, and chemokines. High CD8+ TIL numbers were correlated to improve clinical outcome in HPV-negative HPSCC.

CONCLUSIONS

High expression of immune proteins in HPV-positive HPSCC may explain the better clinical outcome. CD8+ TILs are of relevance for outcome of HPV-negative HPSCC, while tumors with high immune activity but poor patient survival suggest a role for immune therapy.

Programmed Death Ligand 1: A Poor Prognostic Marker in Endometrial Carcinoma

Endometrial carcinoma is the only gynaecologic malignancy with a raising incidence and mortality, posing a major health concern worldwide. The upregulation of programmed death ligand 1 (PD-L1) on tumour cells causes T-cell suppression, which impedes antitumour immunity, promotes immune cell evasion and enhances tumour survival. The aim of this study was to evaluate PD-L1 expression in endometrial carcinoma and to correlate it with survival rate. A total of 59 cases of endometrial carcinoma were evaluated. Thirty-two cases of non-neoplastic endometrial tissue were included as control. PD-L1 immunohistochemistry was performed on all cases. PD-L1 expression was evaluated on tumour cells and immune cells. PD-L1 was positive in 62.7% (37/59) and 28.8% (17/59) of immune cells and tumour cells, respectively. PD-L1 expression in immune cells was significantly higher in endometrial carcinoma than in non-neoplastic endometrium (p < 0.001). Among the patients with endometrial carcinoma, PD-L1 expression in tumour cells was significantly higher in patients who died (10/15, 66.7%) compared to those who survived (7/44, 15.9%) (p < 0.001). It is noteworthy to point out that the expression of PD-L1 in tumour cells was significantly associated with a poor survival. This suggests that immunomodulation using PD-L1 inhibitors may be useful in advanced endometrial carcinoma.

Prognostic role of programmed death ligand 1 (PD-L1) and the immune microenvironment in laryngeal carcinoma

OBJECTIVES

The immune system is crucial in the evolution of head and neck cancer. Programmed cell death ligand 1 (PD-L1) seems to rely on close relations between neoplastic cells and immune cells in the tumor microenvironment. The main aim of this study was to apply univariate/multivariate analysis to investigate the prognostic significance of PD-L1, tumor-infiltrating lymphocytes (TILs), and tertiary lymphoid structures (TLS) in laryngeal carcinoma (LSCC).

MATERIALS AND METHODS

PD-L1 (in terms of combined positive score [CPS]), TILs and TLS were assessed at pathology on 70 consecutive samples of LSCC.

RESULTS

A CPS ≥ 1 coincided with a lower recurrence rate (RR) (p = 0.007) and longer disease-free survival (DFS) than a CPS < 1 (p = 0.0027). Cases with higher TIL counts showed a lower RR (p = 0.036) and longer DFS than those with lower TIL counts (p = 0.0062). Cases revealing TLS had a lower RR (p = 0.004) and longer DFS (p = 0.0034) than those with no TLS. On multivariate analysis, the presence of TLS retained its positive prognostic value (p = 0.024), while CPS remained significant as regards disease recurrence (p = 0.050).

CONCLUSIONS

PD-L1 seems to be an indirect marker of effective anti-tumor response in LSCC, possibly being expressed as a result of a greater immune pressure on cancer cells. The presence of TLS emerged as a positive prognostic factor. Further prospective studies are needed to characterize the role of PD-L1 as a marker of anti-tumor immune response and prognostic factor in LSCC, also with regard to the effectiveness of immunotherapeutic protocols.

Differential Expression and Clinicopathological Significance of HER2, Indoleamine 2,3-Dioxygenase and PD-L1 in Urothelial Carcinoma of the Bladder

Purpose: Evasion of the immune system by cancer cells allows for the progression of tumors. Antitumor immunotherapy has shown remarkable effects in a diverse range of cancers. The aim of this study was to determine the clinicopathological significance of human epidermal growth factor receptor 2 (HER2), indoleamine 2,3-dioxygenase (IDO), and programmed death ligand-1 (PD-L1) expression in urothelial carcinoma of the bladder (UCB). Materials and Methods: We retrospectively studied 97 patients with UCB. We performed an immunohistochemical study to measure the expression levels of HER2, IDO, and PD-L1 in UCB tissue from these 97 patients. Results: In all 97 cases, the PD-L1 expression of tumor-infiltrating immune cells (ICs) was significantly correlated with higher pathologic tumor stage (pT). In pT2–pT4 cases (n = 69), higher levels of HER2 and IDO expression in invasive tumor cells (TCs) were associated with shorter periods of disease-free survival (DFS). Conclusion: These results imply that the expression of PD-L1 in ICs of the UCB microenvironment is associated with cancer invasion and the expression of HER2 or IDO in the invasive cancer cell and suggestive of the potential for cancer recurrence. We suggest that the expression levels of IDO, HER2, and PD-L1 could be useful as targets in the development of combined cancer immunotherapeutic strategies.

Concordance of tumor infiltrating lymphocytes, PD-L1 and p16 expression in small biopsies, resection and lymph node metastases of oropharyngeal squamous cell carcinoma

OBJECTIVE

The incidence of oropharyngeal squamous cell carcinoma (OPSCC), especially human papillomavirus (HPV)-associated, is increasing worldwide. Immunotherapy become available for patients with carcinomas in the head and neck region, however without ideal biomarker. Markers like PD-L1 vary in the clone of the antibody used, and the method of evaluation. Adequate and reliable immune cells characterization and evaluation is still not found. Furthermore, studies analyzing representativeness of different tissue samples are scarce. We analyzed small biopsy, lymph node (LN) metastasis and resected OPSCC, in regards of tumor infiltrating lymphocyte (TIL) density, PD-L1 and p16 expression.

MATERIAL AND METHODS

Patients with OPSCC diagnosed from 2000 to 2016, with small biopsy, resection specimen and LN metastasis samples were selected. We analyzed TILs on hematoxylin-eosin stain, and PD-L1 and p16 expression in tumor cells. Concordance between different tumor locations was evaluated.

RESULTS

93 patients, with 65 small biopsies, 72 resection specimens, and 70 LN metastases were included. TILs, p16 and PD-L1 demonstrated very high concordance. Additionally, PD-L1 expression in the small biopsies was more representative of the PD-L1 expression in the resection specimens, than the LN samples.

CONCLUSION

TILs density can be reliably assessed using hematoxylin-eosin stain with high concordance between the small biopsy, resection specimen and LN metastasis. Evaluation of concordance of p16 expression is very high, nevertheless some cases might be misdiagnosed on a small biopsy or lymph node metastasis. Evaluation of PD-L1 expression is very reliable on the biopsy specimen. Different PD-L1 clones and methods of evaluation still remain to be addressed.

Laryngeal Tumor Microenvironment

Tumor microenvironment has been extensively studied in various forms of cancer, like head and neck squamous cell carcinoma. Progress in the field revealed the prognostic significance of the various components of the tumor's ecosystem and led to changes in treatment strategies, like including immunotherapy as an important tool. In this chapter, the microenvironment of tumors with a special interest in laryngeal cancer will be described. The issues assessed include innate immune response factors, like neutrophils, neutrophil extracellular traps (NET), platelets, macrophages M1 or M2, dendritic cells, natural killer cells, as well as adaptive immunity aspects, like cytotoxic, exhausted and regulatory T cells, and immune checkpoints (PD-1/PD-L1, CTLA4). Also, stroma-associated factors, like fibroblasts, fibrosis, extracellular matrix, vessels and perineural invasion, hypoxia and cancer metabolism aspects, as well as the pre-metastatic niche, exosomes and cGAS-STING, are reviewed.

The Potential Impact of Connexin 43 Expression on Bcl-2 Protein Level and Taxane Sensitivity in Head and Neck Cancers-In Vitro Studies

The poor prognosis of head and neck squamous cell carcinoma (HNSCC) is partly due to the lack of reliable predictive markers. Connexin 43 (Cx43) protein and its cell-communication channels have been assigned tumor suppressor functions while the anti-apoptotic Bcl-2 (B-cell lymphoma-2) protein has been associated with negative prognostic significance in cancer. This study aimed to test the role of Cx43 protein on Bcl-2 expression, tumor progression and response to taxane-based treatment in HNSCC. Human papillomavirus (HPV) negative HNSCC cell lines were tested for paclitaxel sensitivity through measuring apoptosis induction, cell viability and changes in Cx43 and Bcl-2 levels using flow cytometry, cell viability assay, immunocytochemistry and western blot. Inhibition of Cx43 expression using siRNA increased Bcl-2 protein levels in SCC25 (tongue squamous cell carcinoma) cells, while forced Cx43 expression reduced Bcl-2 levels and supported paclitaxel cytotoxicity in FaDu (hypopharynx squamous cell carcinoma) cells. In vitro results were in line with protein expression and clinicopathological features tested in tissue microarray samples of HNSCC patients. Our data demonstrate that elevated Cx43 and reduced Bcl-2 levels may indicate HNSCC sensitivity to taxane-based treatments. On the contrary, silencing of the Cx43 gene GJA1 (gap junction protein alpha-1) can result in increased Bcl-2 expression and reduced paclitaxel efficiency. Clinical tumor-based analysis also confirmed the inverse correlation between Cx43 and Bcl-2 expression.

The Controversial Role of PD-1 and Its Ligands in Gynecological Malignancies

The programmed death-1 (PD-1, CD279) receptor with its ligands, programmed death ligand 1 (PD-L1, CD274, B7-H1), and programmed death ligand 2 (PD-L2, CD273, B7-DC), are the key players of one of the immune checkpoint pathways inhibiting T-cell activation. PD-L1 and PD-L2 are expressed in different cancer cells and their microenvironment, including infiltrating immune cells. However, their prognostic value is still debated and their role in the tumor microenvironment has not been fully elucidated yet. Considering the importance that cancer immunotherapy with anti-PD-1 and anti-PD-L1 antibodies gained in several tumor types, in this review article we aim to discuss the role of the PD-1/PD-L1/PD-L2 axis in gynecological cancers. PD-1 ligands have been detected in ovarian, cervical, vulvar and uterine cancers, and correlation with prognosis seems dependent from their distribution. About PD-L2, very few reports are available so far in gynecological malignancies, and its role is still not completely understood. Clinical trials using anti-PD-1 or anti-PD-L1 antibodies, but not anti-PD-L2, are currently ongoing, in all types of gynecological cancers. They have shown good safety profiles in a certain cohort of patients, but response rates remain low and many aspects remain controversial. In this review, we propose possible solutions to enhance the clinical efficacy of PD-1 axis targeting therapies. Regarding PD-L2, it might be useful to better clarify its role in order to improve the efficiency of immunotherapy in female malignancies.

PD-1 and PD-L1 Expression Predicts Radiosensitivity and Clinical Outcomes in Head and Neck Cancer and is Associated with HPV Infection

Objectives: PD-1 and PD-L1 overexpression in malignant tumors in response to radiotherapy is correlated with a poor prognosis. Human papilloma virus (HPV) infection impacts intrinsic radiosensitivity of head and neck cancers (HNCs). Herein, this study aims to determine PD-1/PD-L1 expression differences in tumors with different HPV statuses and their prognostic value in patients with different radiosensitivity gene signatures to define the characteristics of patients who will benefit from radiotherapy combined with anti-PD-1/PD-L1 therapy. Material and methods: According to the identified gene signature related to radiosensitivity, 517 patients from the TCGA HNSCC cohort were selected and divided into the radioresistant (RR) group and radiosensitive (RS) group using a K-mean clustering algorithm. All data analyses were conducted using SPSS and GraphPad Prism. Results: PD-L1 expression is upregulated in tumor tissue (unpaired t test, P=0.0363; paired t test, P=0.0584) compared with normal tissue. PD-L1 was positively correlated with PD-1 expression (P<0.0001). The HPV/p16-positive group was significantly high PD-1 expression (P<0.0001). PD-L1 expression (P=0.0005) and PD-1 expression (P<0.0001) were significantly increased in the RS group compared with that in the RR group. In the patients who were treated with radiotherapy, the PD-1-high group was associated with better recurrence-free survival (RFS) (HR, 0.4892; 95% CI, 0.2357-1.015; P=0.023). Within the RR group, high PD-L1 expression was associated with reduced overall survival (OS) (HR, 2.196; 95% CI, 1.081-4.46; P=0.0108) compared with low PD-L1 expression. In the RR group, HPV/p16-negative patients with high PD-L1 expression exhibited reduced OS (HPV: HR, 2.334; 95% CI, 0.7828-6.961; P=0.0313; p16: HR,2.486; 95% CI, 0.8559-7.219; P=0.0192) compared with that of patients with low PD-L1 expression. In the PD-L1-high group, RR patients exhibited reduced OS (HR, 0.4858; 95% CI, 0.2136-1.105; P=0.0189) and RFS (HR, 0.4371; 95% CI, 0.1421-1.345; P=0.0231) compared with that of RS patients. Conclusion: Our findings demonstrated that high PD-1/PD-L1 expression was strongly related to radiosensitivity, and high PD-1 expression was significantly associated with HPV/p16-positive HNCs. Patients in the radioresistant group and patients in the HPV/p16-negative group with a radioresistant gene signature could benefit from the combination of radiotherapy and anti-PD-1/PD-L1 therapy.

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.

Low PD-L1 Expression Strongly Correlates with Local Recurrence in Epstein-Barr Virus-Positive Nasopharyngeal Carcinoma after Radiation-Based Therapy

The prognostic value of programmed death-ligand 1 (PD-L1) expression in nasopharyngeal carcinoma (NPC) is controversial, with previous studies showing conflicting results. Most NPCs in endemic areas are Epstein-Barr virus (EBV)-positive. Our aim was to evaluate the clinical significance of PD-L1 expression in EBV-positive NPC. We retrospectively analyzed PD-L1 expression on tumor cells (TCs) and immune cells (ICs) by immunohistochemistry in 208 EBV-positive NPC patients who underwent radiotherapy (203 with concurrent chemotherapy). The percentages of TCs and ICs expressing PD-L1 were evaluated respectively. There was a strong correlation between local recurrence and low PD-L1 expression on ICs (p = 0.0012), TCs (p = 0.013) or both (p = 0.000044), whereas all clinical parameters had no influence on local recurrence. Using multivariate analysis, low PD-L1 expression on ICs was an independent adverse prognostic factor (p = 0.0080; HR = 1.88; 95% CI = 1.18⁻3.00) for disease-free survival. High PD-L1 expression on both ICs and TCs was an independent favorable prognostic factor (p = 0.022; HR = 0.46; 95% CI = 0.24⁻0.89) for overall survival. We show for the first time that low PD-L1 expression on ICs and TCs strongly correlates with local recurrence in EBV-positive NPC patients after radiation-based therapy. A simple immunohistochemical study for PD-L1 can identify patients prone to local recurrence, and such patients might benefit from more aggressive treatment in future clinical trials.