Prognostic markers in oropharyngeal squamous cell carcinoma: focus on CD70 and tumour infiltrating lymphocytes

Immune-scoring in head and neck squamous cell carcinoma: a scoping review

INTRODUCTION

Head and neck squamous cell carcinomas (HNSCCs) have an increasing incidence, high recurrence, and an overall unfavorable prognosis despite numerous treatment options. The distinct immune landscape of HNSCC suggests a potential for immune-related biomarkers to aid classification and treatment planning.

AREAS COVERED

Immunoscore, a multiplex measure of tumor-infiltrating immune cells, is currently approved in colorectal carcinoma and is under investigation in various other cancer types. Recent studies have tried to implement the immunoscore and other novel immune cell-based scoring systems in HNSCC as predictors of survival. This study provides an overview of tumor-infiltrating immune cells and their prognostic significance, as well as a comparative summary of studies introducing an immunoscore in HNSCC.

EXPERT OPINION

With sufficient insight of the current literature, future studies could lead to the definition and validation of a new immune-based classification system for HNSCC. Such a classification strategy could be the basis for patient selection and, thus, optimize treatment outcomes and reduce unwanted complications. The heterogeneity of HNSCC subtypes, as well as the intratumoral variability of immune infiltrates, should be accounted for in the immunoscore.

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.

Analysis of cells of epithelial, connective tissue and immune differentiation in HPV-positive-, HPV-negative oropharyngeal carcinoma and normal oropharyngeal tissue by immunofluorescence multiplex image cytometry: a preliminary report

BACKGROUND

Epithelial, connective tissue and immune cells contribute in various ways to the pathophysiology of HPV positive (HPV+) and HPV negative (HPV-) oropharyngeal squamous cell carcinoma (OPSCC). We aimed to investigate the abundance of these cell lineages and their coexpression patterns in patients with HPV + and HPV- OPSCC.

METHODS

We used a 4-channel immunofluorescence-microscopy technique for the simultaneous detection of three direct-conjugated antibodies (pancytokeratin, vimentin and CD45/CD18) and DAPI (4',6-Diamidin-2-phenylindole) in formalin fixed paraffin-embedded tissue samples (FFPE) of patients with HPV + and HPV- OPSCC, and of control patients. Image acquisition and analysis were performed with TissueFAXS and StrataQuest (TissueGnostics, Vienna, Austria), respectively, in tumor cell clusters/stroma in OPSCC specimens and epithelial layer/lamina propria in control specimens. Cell populations were created based on antibodies' coexpression patterns. Isotype and positive controls were examined for plausibility.

RESULTS

The proportion of cells of epithelial differentiation in tumor cell clusters was higher in HPV + OPSCC (55%) than in HPV- OPSCC samples (44%). The proportion of connective tissue cells in tumor cell cluster was lower in HPV + OPSCC patients (18%) than in HPV- OPSCC patients (26%). The proportion of immune cells in tumor cell clusters was higher in HPV + OPSCC patients (25%) than in HPV- OPSCC patients (18%). The percentage of anaplastic, potentially de-differentiated cells, was 2% in control patients, and it was higher in HPV- OPSCC (21%) than in HPV + OPSCC samples (6%).

CONCLUSIONS

This study provided the first quantitative data for the abundance of cells of epithelial, connective tissue and immune differentiation, in patients with OPSCC and control patients. The abundance of these different crucial cell populations was consistently originating from the same tissue sample. De-differentiation of tumor cells was higher in HPV- OPSCC than in HPV + OPSCC. In tumor cells clusters, the antitumoral host immune response was higher in HPV + OPSCC than in HPV- OPSCC, whereas the fibroblast response was higher in HPV- OPSCC than in HPV + OPSCC. This study contributed to the understanding of histopathologic differences between HPV + OPSCC and HPV- OPSCC patients.

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.

Tumor-Infiltrating Lymphocytes in Head and Neck Cancer: Ready for Prime Time?

The evaluation of tumor-infiltrating lymphocytes (TILs) has received global attention as a promising prognostic cancer biomarker that can aid in clinical decision making. Proof of their significance was first shown in breast cancer, where TILs are now recommended in the classification of breast tumors. Emerging evidence indicates that the significance of TILs extends to other cancer types, including head and neck cancer. In the era of immunotherapy as a treatment choice for head and neck cancer, assessment of TILs and immune checkpoints is of high clinical relevance. The availability of the standardized method from the International Immuno-oncology Biomarker Working Group (IIBWG) is an important cornerstone toward standardized assessment. The aim of the current article is to summarize the accumulated evidence and to establish a clear premise for future research toward the implementation of TILs in the personalized management of head and neck squamous cell carcinoma patients.

Prognostic Relevance of CD4+, CD8+ and FOXP3+ TILs in Oral Squamous Cell Carcinoma and Correlations with PD-L1 and Cancer Stem Cell Markers

This study investigates the relevance of tumor-infiltrating lymphocytes (TILs) in oral squamous cell carcinoma (OSCC). Immunohistochemical analysis of stromal/tumoral CD4⁺, CD8⁺ and FOXP3⁺ TILs is performed in 125 OSCC patients. Potential relationships with the expression of tumoral PD-L1 and cancer stem cell (CSC) markers (NANOG, SOX2, OCT4, Nestin and Podoplanin (PDPN)) are assessed. CD4⁺ and CD8⁺ TILs are significantly associated with smoking and alcohol habits. CD4⁺ and CD8⁺ TILs show an inverse relationship with NANOG and SOX2 expression, and FOXP3⁺ TILs is significantly correlated with Nestin and PDPN expression. High infiltration of CD4⁺ and CD8⁺ TILs and a high tumoral CD8⁺/FOXP3⁺ ratio are significantly associated with tumors harboring positive PD-L1 expression. Infiltration of stromal/tumoral FOXP3⁺ TILs and a low stromal CD8⁺/FOXP3⁺ ratio are significantly associated with better disease-specific survival. Multivariate analysis reveals that the stromal CD8⁺/FOXP3⁺ TILs ratio is a significant independent prognostic factor. Regarding OSCC patient survival, the CD8⁺/FOXP3⁺ TILs ratio is an independent prognostic factor. TILs may act as biomarkers and potential therapeutic targets for OSCC.

Development of Exhaustion and Acquisition of Regulatory Function by Infiltrating CD8+CD28- T Lymphocytes Dictate Clinical Outcome in Head and Neck Cancer

Simple Summary

CD8+ T lymphocytes are among the immune cells reputed to kill tumor cells. Head and neck squamous cell carcinoma (HNSCC) has a poor clinical outcome despite the presence of a rich CD8+ T cell tumor infiltrate. This may be due to alterations of tumor infiltrating CD8+ T cells. Here, we performed a characterization of infiltrating CD8+ T cells in a cohort of 30 HNSCC patients. The results showed that differential intratumoral frequency of CD8+CD28+ T cells, CD8+CD28− T cells, and CD8+CD28−CD127−CD39+ Treg distinguished between HNSCC patients who did or did not respond to treatment. Moreover, we identified an intratumoral CD8+CD28- T cell subpopulation, which expressed markers of both exhausted (i.e., with impaired effector functions) and regulatory (i.e., exerting suppressive activities) cells. This suggests that in HNSCC effector T cells progressively undergo exhaustion and acquisition of regulatory properties, hampering their anti-tumor functions.

Abstract

Head and neck squamous cell carcinoma (HNSCC) has a poor clinical outcome despite the presence of a rich CD8+ T cell tumor infiltrate in the majority of patients. This may be due to alterations of tumor infiltrating CD8+ T cells. Here, we performed a characterization of HNSCC infiltrating CD8+ T cells in a cohort of 30 patients. The results showed that differential intratumoral frequency of CD8+CD28+ T cells, CD8+CD28− T cells, and CD8+CD28−CD127−CD39+ Treg distinguished between HNSCC patients who did or did not respond to treatment. Moreover, high PD1 expression identified a CD8+CD28− T cell subpopulation, phenotypically/functionally corresponding to CD8+CD28−CD127−CD39+ Treg, which showed a high expression of markers of exhaustion. This observation suggests that development of exhaustion and acquisition of regulatory properties may configure the late differentiation stage for intratumoral effector T cells, a phenomenon we define as effector-to-regulatory T cell transition.

Immuno-Oncological Biomarkers for Squamous Cell Cancer of the Head and Neck: Current State of the Art and Future Perspectives

The era of immune checkpoint inhibitors has altered the therapeutic landscape in squamous cell cancer of the head and neck (SCCHN). Our knowledge about the tumor microenvironment has fueled the research in SCCHN, leading to several well-known and less-known prognostic and predictive biomarkers. The clinical staging, p16/HPV status, and PD-L1 expression are currently the main tools for assessing the patients' diagnosis and prognosis. However, several novel biomarkers have been thoroughly investigated, some reaching actual significant clinical contributions. The untangling of the immune infiltrate with the subtyping of tissue-associated tumor infiltrating lymphocytes, tumor-associated macrophages, and circulating blood-based biomarkers are an interesting avenue to be further explored and prospectively assessed. Although PD-L1 expression remains the most important response predictor for immune checkpoint inhibitors, several flaws impede proper assessment such as technical issues, different scoring protocol, and intra-, inter-, and temporal heterogeneity. In addition, the construction of an immune-related gene panel has been proposed as a prognostic and predictive stratification but lacks consensus. Recently, the role of microbioma have also been explored regarding its systemic and antitumor immunity. This review gives a comprehensive overview of the aforementioned topics in SCCHN. To this end, the integration of these clinically advantageous biomarkers via construction of an immunogram or nomogram could be an invaluable tool for SCCHN in future prospects.

Prognostic Significance of CD4+ and CD8+ Tumor-Infiltrating Lymphocytes in Head and Neck Squamous Cell Carcinoma: A Meta-Analysis

Simple Summary

Tumor infiltrating lymphocytes (TILs) have been demonstrated as prognostic biomarkers in multiple cancer types. Among the various TIL phenotypic sub-populations, T-cells are most abundant. Several studies have investigated the prognostic value of CD4+ and CD8+ T-cell TILs in head and neck squamous cell carcinoma (HNSCC). In this study we performed a systematic review and meta-analysis of available evidence for CD4+ and CD8+ TIL biomarkers in HNSCC. The primary aim was to investigate the correlation of TIL sub-population levels and overall survival in HNSCC anatomical sub-sites. We demonstrate for the first time that tumor location has a significant impact upon the prognostic utility of CD4+ and CD8+ TILs in HNSCC. Such data is of critical importance when incorporating TIL biomarkers into current prognostic models and clinical practice.

Abstract

Objective: It has been suggested that the presence of tumor-infiltrating lymphocytes (TILs) in the tumor microenvironment is associated with a better prognosis in different types of cancer. In this systematic review and meta-analysis, we investigated the prognostic role of CD4+ and CD8+ TILs in head and neck squamous cell carcinoma (HNSCC). Methods: PubMed, Cochrane, Embase, Scopus, and Web of Science were searched up to September 2020. This study was conducted following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) checklist. Risk ratios from individual studies were displayed in forest plots and the pooled hazard ratios (HR) of death and corresponding confidence intervals (CI) were calculated according to random-effects models. Risk of bias of the included studies was assessed through the Newcastle–Ottawa scale. Results: 28 studies met the inclusion criteria. Studies conducted on HNSCC subsites combined reported a significant reduction in the risk of death for both high CD4+ (HR: 0.77; 95% CI: 0.65–0.93) and high CD8+ TILs (HR: 0.64; 95% CI: 0.47–0.88). High CD4+ TILs were associated with significantly better overall survival among oropharyngeal HNSCC (HR: 0.52; 95% CI: 0.31–0.89), as well as high CD8+ TILS in Human papillomavirus −ve and +ve cancers (HR: 0.39; 95% CI: 0.16–0.93 and HR: 0.40; 95% CI 0.21–0.76 respectively). CD8+ TILs were also associated with improved survival in hypopharyngeal cancers (HR = 0.43 CI: 0.30–0.63). No significant association emerged for patients with cancer of the oral cavity or larynx. Conclusions: The findings from this meta-analysis demonstrate the prognostic significance of CD8+ and CD4+ TILs in HNSCC and variation in tumor subsite warrants further focused investigation. We highlight how TILs may serve as predictive biomarkers to risk stratify patients into treatment groups, with applications in immune-checkpoint inhibitors notable areas for further research.

CD8+ CD73+ T cells in the tumor microenvironment of head and neck cancer patients are linked to diminished T cell infiltration and activation in tumor tissue

Recent studies have implicated a role for adenosine-dependent immunosuppression in head and neck tumor microenvironments. We describe expression of CD73, an enzyme critical to the generation of adenosine from extracellular AMP, in T cells and other cell types within human head and neck tumors. Flow cytometric analyses of tumor-infiltrating cells indicate that CD3⁺ cells are the predominant source of CD73 among immune infiltrating cells and that CD73 expression, especially among CD8⁺ T cells, is inversely related to indices of T cell infiltration and T cell activation in the microenvironment of head and neck tumors. We provide evidence that CD73 expression on peripheral T cells and levels of soluble CD73 in circulation are correlated with CD73 expression on CD8⁺ T cells in tumors. Moreover, fluorescent microscopy studies reveal that CD8⁺ CD73⁺ cells are observed in close proximity to tumor cells as well as in surrounding tissue. In vitro studies with peripheral blood T cells indicate that anti-CD3-stimulation causes loss of CD73 expression, especially among cells that undergo proliferation and that exogenous AMP can impair T cell proliferation, while sustaining CD73 expression. These data suggest that CD8⁺ CD73⁺ T cells may be especially important mediators of immunosuppression in human head and neck cancer.

HPV Involvement in the Tumor Microenvironment and Immune Treatment in Head and Neck Squamous Cell Carcinomas

Head and neck squamous cell carcinomas (HNSCC) are one of the most prevalent cancers worldwide. Active human papillomavirus (HPV) infection has been identified as an important additional risk factor and seems to be associated with a better prognosis in non-drinker and non-smoker young patients with oropharyngeal SCC. The better response of the immune system against the HPV-induced HNSCC is suspected as a potential explanation for the better prognosis of young patients. To further assess this hypothesis, our review aims to shed light the current knowledge about the impact of HPV infection on the immune response in the context of HNSCC, focusing on the innate immune system, particularly highlighting the role of macrophages, Langerhans and myeloid cells, and on the adaptative immune system, pointing out the involvement of T regulatory, T CD8 and T CD4 lymphocytes. In addition, we also review the preventive (HPV vaccines) and therapeutic (checkpoint inhibitors) strategies against HPV-related HNSCC, stressing the use of anti-CTLA4, PD-L1, PD-L2 antibodies alone and in combination with other agents able to modulate immune responses.

Apparent Lack of BRAF V600E Derived HLA Class I Presented Neoantigens Hampers Neoplastic Cell Targeting by CD8+ T Cells in Langerhans Cell Histiocytosis

Langerhans Cell Histiocytosis (LCH) is a neoplastic disorder of hematopoietic origin characterized by inflammatory lesions containing clonal histiocytes (LCH-cells) intermixed with various immune cells, including T cells. In 50-60% of LCH-patients, the somatic BRAF ^V600E driver mutation, which is common in many cancers, is detected in these LCH-cells in an otherwise quiet genomic landscape. Non-synonymous mutations like BRAF ^V600E can be a source of neoantigens capable of eliciting effective antitumor CD8⁺ T cell responses. This requires neopeptides to be stably presented by Human Leukocyte Antigen (HLA) class I molecules and sufficient numbers of CD8⁺ T cells at tumor sites. Here, we demonstrate substantial heterogeneity in CD8⁺ T cell density in n = 101 LCH-lesions, with BRAF ^V600E mutated lesions displaying significantly lower CD8⁺ T cell:CD1a⁺ LCH-cell ratios (p = 0.01) than BRAF wildtype lesions. Because LCH-lesional CD8⁺ T cell density had no significant impact on event-free survival, we investigated whether the intracellularly expressed BRAF ^V600E protein is degraded into neopeptides that are naturally processed and presented by cell surface HLA class I molecules. Epitope prediction tools revealed a single HLA class I binding BRAF ^V600E derived neopeptide (KIGDFGLATEK), which indeed displayed strong to intermediate binding capacity to HLA-A^*03:01 and HLA-A^*11:01 in an in vitro peptide-HLA binding assay. Mass spectrometry-based targeted peptidomics was used to investigate the presence of this neopeptide in HLA class I presented peptides isolated from several BRAF ^V600E expressing cell lines with various HLA genotypes. While the HLA-A^*02:01 binding BRAF wildtype peptide KIGDFGLATV was traced in peptides isolated from all five cell lines expressing this HLA subtype, KIGDFGLATEK was not detected in the HLA class I peptidomes of two distinct BRAF ^V600E transduced cell lines with confirmed expression of HLA-A^*03:01 or HLA-A^*11:01. These data indicate that the in silico predicted HLA class I binding and proteasome-generated neopeptides derived from the BRAF ^V600E protein are not presented by HLA class I molecules. Given that the BRAF ^V600E mutation is highly prevalent in chemotherapy refractory LCH-patients who may qualify for immunotherapy, this study therefore questions the efficacy of immune checkpoint inhibitor therapy in LCH.

Biological Determinants of Chemo-Radiotherapy Response in HPV-Negative Head and Neck Cancer: A Multicentric External Validation

Purpose: Tumor markers that are related to hypoxia, proliferation, DNA damage repair and stem cell-ness, have a prognostic value in advanced stage HNSCC patients when assessed individually. Here we aimed to evaluate and validate this in a multifactorial context and assess interrelation and the combined role of these biological factors in determining chemo-radiotherapy response in HPV-negative advanced HNSCC. Methods: RNA sequencing data of pre-treatment biopsy material from 197 HPV-negative advanced stage HNSCC patients treated with definitive chemoradiotherapy was analyzed. Biological parameter scores were assigned to patient samples using previously generated and described gene expression signatures. Locoregional control rates were used to assess the role of these biological parameters in radiation response and compared to distant metastasis data. Biological factors were ranked according to their clinical impact using bootstrapping methods and multivariate Cox regression analyses that included clinical variables. Multivariate Cox regression analyses comprising all biological variables were used to define their relative role among all factors when combined. Results: Only few biomarker scores correlate with each other, underscoring their independence. The different biological factors do not correlate or cluster, except for the two stem cell markers CD44 and SLC3A2 (r = 0.4, p < 0.001) and acute hypoxia prediction scores which correlated with T-cell infiltration score, CD8⁺ T cell abundance and proliferation scores (r = 0.52, 0.56, and 0.6, respectively with p < 0.001). Locoregional control association analyses revealed that chronic (Hazard Ratio (HR) = 3.9) and acute hypoxia (HR = 1.9), followed by stem cell-ness (CD44/SLC3A2; HR = 2.2/2.3), were the strongest and most robust determinants of radiation response. Furthermore, multivariable analysis, considering other biological and clinical factors, reveal a significant role for EGFR expression (HR = 2.9, p < 0.05) and T-cell infiltration (CD8⁺T-cells: HR = 2.2, p < 0.05; CD8⁺T-cells/Treg: HR = 2.6, p < 0.01) signatures in locoregional control of chemoradiotherapy-treated HNSCC. Conclusion: Tumor acute and chronic hypoxia, stem cell-ness, and CD8⁺ T-cell parameters are relevant and largely independent biological factors that together contribute to locoregional control. The combined analyses illustrate the additive value of multifactorial analyses and support a role for EGFR expression analysis and immune cell markers in addition to previously validated biomarkers. This external validation underscores the relevance of biological factors in determining chemoradiotherapy outcome in HNSCC.

Enhanced Radiation Sensitivity of Human Papillomavirus-Driven Head and Neck Cancer: Focus on Immunological Aspects

Head and neck squamous cell carcinomas (HNSCC), emerging in the mucosa of the upper aerodigestive tract, are associated with either the classical risk factors, tobacco and alcohol consumption, or with infections with high-risk types of the human papillomavirus (HPV). Depending on the involvement of HPV, HNSCC follow different pathways of carcinogenesis and show distinct clinical presentations regarding survival, prognosis and treatment response. For instance, HPV-driven HNSCC exhibit an enhanced radiation response compared to their typically radioresistant HPV-negative counterparts. Although radiosensitivity of HNSCC has been studied by many research groups, the major causes for the difference in radiation responses between HPV-driven and HPV-negative HNSCC are still an open question. In this mini review, we discuss the reported cellular and immunological factors involved in the enhanced radiation response in HPV-driven HNSCC, focusing on the vital role of the immune response in the outcome of HNSCC radiotherapy.

Impact of HPV Infection on the Immune System in Oropharyngeal and Non-Oropharyngeal Squamous Cell Carcinoma: A Systematic Review

Objectives: To review the current knowledge regarding the involvement of human papilloma virus (HPV) infection and the immune system in the development of head and neck squamous cell carcinoma (HNSCC). Methods: An electronic literature search was conducted to identify articles published between 1990 and 2019 pertaining to tumor-infiltrating immune cells (TICs) in HNSCC using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Issues of clinical relevance, including tumor location, the number of tumor samples, the inclusion of additional specimens (dysplastic or normal mucosa), tumor size, methods used for HPV detection, relationship between antigen expression and patient characteristics (age, gender, smoking, alcohol consumption, etc.), and prognostic data (overall survival (OS) and recurrence-free survival (RFS)) were assessed by four blinded investigators. Results: The search identified 335 relevant studies, of which 41 met the inclusion criteria. Of these, 7 studies focused on the peripheral blood immune cell concentration in patients with HNSCC according to HPV status, and 36 studies investigated TICs in the intraepithelial and/or stromal compartment(s) according to HPV status. The immune cells studied were CD8+ T cells (N = 19), CD4+ T cells (N = 7), regulatory T cells (Tregs, N = 15), macrophages (N = 13), myeloid-derived suppressor cells (MDSCs, N = 4), and Langerhans cells (LCs, N = 2). Conclusions: Irrespective of tumor location, CD8+ and CD4+ T cells appear to play a key role in the development of HPV−related HNSCC, and their infiltration is likely associated with a significant impact on OS and RFS. To date, the roles and prognostic value of Tregs, macrophages, DCs and MDSCs remain unclear.

Effect of tumor microenvironment on pathogenesis of the head and neck squamous cell carcinoma: a systematic review

The tumor microenvironment (TME) is comprised of many different cell populations, such as cancer-associated fibroblasts and various infiltrating immune cells, and non-cell components of extracellular matrix. These crucial parts of the surrounding stroma can function as both positive and negative regulators of all hallmarks of cancer development, including evasion of apoptosis, induction of angiogenesis, deregulation of the energy metabolism, resistance to the immune detection and destruction, and activation of invasion and metastasis. This review represents a summary of recent studies focusing on describing these effects of microenvironment on initiation and progression of the head and neck squamous cell carcinoma, focusing on oral squamous cell carcinoma, since it is becoming clear that an investigation of differences in stromal composition of the head and neck squamous cell carcinoma microenvironment and their impact on cancer development and progression may help better understand the mechanisms behind different responses to therapy and help define possible targets for clinical intervention.

Utility of CD8 score by automated quantitative image analysis in head and neck squamous cell carcinoma

INTRODUCTION

In head and neck squamous cell carcinoma (HNSCC) high numbers of tumor infiltrating CD8 T cells in the tumor microenvironment are associated with better outcome. However, no investigators have employed automated image analysis on whole slide images to permit CD8 scores for use in clinical practice. The aim of this study was to develop and validate an image analysis algorithm to automatically quantify CD8 T cells in patients with oropharyngeal HNSCC.

MATERIALS AND METHODS

Using brightfield image analysis results were cross-validated with fluorescence based quantification (AQUA™). A nuclear image algorithm designed to run on whole slide images was optimized to manual count. The algorithm was locked down and used on a cohort of whole tissue sections from HNSCC patients. Multivariate clinicopathologic parameters and outcomes were statistically correlated with image analysis results.

RESULTS

Linear correlation between manual counts and the customized CD8 algorithm was 0.943. A total of 74 oropharyngeal HNSCC cases were analyzed for CD8 immune cell infiltrate using this image analysis algorithm. A CD8 immune cell density above 136 cells/mm² was associated with median survival of 18 years compared to 5 years. When multivariate modeling was performed, HPV infection was the only predictor of survival; however, when HPV was excluded only CD8 cell density predicts survival.

CONCLUSIONS

We report the successful technical development and clinical validation of an image algorithm to automate CD8 immune cell density for oropharyngeal HNSCC. Employing brightfield image analysis on entire tumor sections instead of tumor subcompartments permits this strategy to be widely implemented.

PD-L1 Expression and Tumor-Infiltrating Lymphocytes in High-Risk and Metastatic Cutaneous Squamous Cell Carcinoma

OBJECTIVE

To characterize programmed death-ligand 1 (PD-L1) expression and tumor-infiltrating lymphocyte (TIL) positivity for locally aggressive or regionally metastatic cutaneous head and neck squamous cell carcinoma (cHNSCC).

STUDY DESIGN

Retrospective chart review, followed by immunohistochemical staining of archived tumor specimens.

SETTING

Tertiary academic medical center.

SUBJECTS AND METHODS

After identification of 101 patients treated surgically for locally advanced or regionally metastatic cHNSCC, archived tissue was stained and graded for PD-L1 expression in addition to TIL presence. Cross-tabulation was performed to examine the association between either of these variables and clinicopathologic features and outcomes.

RESULTS

A total of 101 patients met inclusion criteria, but archived tissue was available only for 83 (31 primaries, 52 metastases). The majority of primary tumors demonstrated grade 1 PD-L1 staining, while grade 2 staining was more likely for metastases. Neither high- nor low-grade PD-L1 expression correlated with any clinicopathologic variable for primary tumors. However, for metastases, high-grade staining was significantly associated with regional recurrence (15 of 19, P = .02). TILs were present for 65% of primary tumors and 90% of regional metastases but did not correlate with any clinicopathologic variables.

CONCLUSION

Diffuse expression of PD-L1 in this study highlights the possibility of using immunotherapy in the form of programmed death 1/PD-L1 blockade to improve treatment for this devastating disease. However, further studies are needed to clarify the significance of PD-L1 expression and TIL positivity for locally advanced or regionally metastatic cHNSCC.

Importance of choice of materials and methods in PD-L1 and TIL assessment in oropharyngeal squamous cell carcinoma

AIMS

A great deal of research is being conducted into PD-L1 immunohistochemistry (IHC) and tumour-infiltrating lymphocytes (TILs) as predictive or prognostic biomarkers for immunotherapy, although several practical issues exist concerning their assessment. The aim of this research was therefore to assess the importance of choice of materials and methods in PD-L1 and TILs scoring in oropharyngeal squamous cell carcinoma (OSCC).

METHODS AND RESULTS

IHC for PD-L1 (SP142 and 22C3 clone) and TILs subtyping was performed on formalin-fixed paraffin-embedded tissue slides (biopsy, resection and/or lymph nodes specimens) of 99 patients with OSCC. A comparative analysis of PD-L1 and TILs scoring was made between different types of tissue specimens, between different PD-L1 clones, between TILs and different subsets of TILs and between the quantitative and semiquantitative assessments. PD-L1 scoring resulted in fair to moderate agreement for 22C3 and SP142 between various tissue specimens, with higher agreement at higher cut-off values, and in moderate agreement for 22C3 versus SP142. Evaluation by four independent observers proved substantial inter-rater agreement for both clones with high consistency in their ratings. Moderate agreement was observed for TILs and TILs subsets for the comparison between biopsy and resection. Lastly, strong correlations were found between quantitative and semiquantitative assessment for all PD-L1 and TILs scores.

CONCLUSIONS

Our results highlight the challenges associated with the evaluation of PD-L1 and TILs in OSCC. Further research is warranted to evaluate the use of these biomarkers in order to allow implementation of PD-L1 and TILs infiltrate as biomarkers in daily clinical practice.

A defect in KCa3.1 channel activity limits the ability of CD8+ T cells from cancer patients to infiltrate an adenosine-rich microenvironment

The limited ability of cytotoxic T cells to infiltrate solid tumors hampers immune surveillance and the efficacy of immunotherapies in cancer. Adenosine accumulates in solid tumors and inhibits tumor-specific T cells. Adenosine inhibits T cell motility through the A_2A receptor (A_2AR) and suppression of KCa3.1 channels. We conducted three-dimensional chemotaxis experiments to elucidate the effect of adenosine on the migration of peripheral blood CD8⁺ T cells from head and neck squamous cell carcinoma (HNSCC) patients. The chemotaxis of HNSCC CD8⁺ T cells was reduced in the presence of adenosine, and the effect was greater on HNSCC CD8⁺ T cells than on healthy donor (HD) CD8⁺ T cells. This response correlated with the inability of CD8⁺ T cells to infiltrate tumors. The effect of adenosine was mimicked by an A_2AR agonist and prevented by an A_2AR antagonist. We found no differences in A_2AR expression, 3',5'-cyclic adenosine monophosphate abundance, or protein kinase A type 1 activity between HNSCC and HD CD8⁺ T cells. We instead detected a decrease in KCa3.1 channel activity, but not expression, in HNSCC CD8⁺ T cells. Activation of KCa3.1 channels by 1-EBIO restored the ability of HNSCC CD8⁺ T cells to chemotax in the presence of adenosine. Our data highlight the mechanism underlying the increased sensitivity of HNSCC CD8⁺ T cells to adenosine and the potential therapeutic benefit of KCa3.1 channel activators, which could increase infiltration of these T cells into tumors.

Prognostic impact of leukocyte counts before and during radiotherapy for oropharyngeal cancer

Introduction

Peripheral blood count components are accessible and evidently predictive in other cancers but have not been explored in oropharyngeal carcinoma. We examine if there is an association between the use of intensity-modulated radiotherapy (IMRT) or intensity-modulated proton therapy (IMPT) and lymphopenia, as well as if there is an association between baseline neutrophilia, baseline leukocytosis and lymphocyte nadir in oropharyngeal cancer.

Materials and Methods

Analysis started with 150 patients from a previous case to case study design, which retrospectively identified adults with oropharyngeal carcinoma, 100 treated with IMRT in 2010-2012 and 50 treated with IMPT in 2011-2014. Pretreatment leukocyte, neutrophil, lymphocyte, and hemoglobin levels were extracted, as were neutrophil and lymphocyte nadir levels during radiotherapy. We retained 137 patients with recorded pre-treatment leukocyte and neutrophil levels for associated analysis and 114 patients with recorded lymphocyte levels during radiation and associated analysis. Multivariate survival analyses were done with Cox regression.

Results

The radiotherapy type (IMRT vs. IMPT) was not associated with lymphopenia (grade 3 P > .99; grade 4 P = .55). In univariate analyses, poor overall survival was associated with pretreatment neutrophilia (hazard ratio [HR] 5.58, 95% confidence interval [CI] 1.99-15.7, P = .001), pretreatment leukocytosis (HR 4.85, 95% CI 1.73-13.6, P = .003), grade 4 lymphopenia during radiotherapy (HR 3.28, 95% CI 1.14-9.44, P = .03), and possibly smoking status >10 pack-years (HR 2.88, 95% CI 1.01-8.18, P = .05), but only T status was possibly significant in multivariate analysis (HR 2.64, 95% CI 0.99-7.00, P = .05). Poor progression-free survival was associated with pretreatment leukocytosis and T status in univariate analysis, and pretreatment neutrophilia and advanced age on multivariate analysis.

Conclusions

Treatment modality did not affect blood counts during radiotherapy. Pretreatment neutrophilia, pretreatment leukocytosis, and grade 4 lymphopenia during radiotherapy were associated with worse outcomes after, but establishing causality will require additional work with increased statistical power.

Tumor PD-L1 status and CD8+ tumor-infiltrating T cells: markers of improved prognosis in oropharyngeal cancer

Introduction

The aim of this study was to evaluate the expression of PD-L1 in oropharyngeal squamous cell carcinoma. Its relation with clinicopathological variables, tumor infiltrating lymphocytes and survival was also determined.

Results

Positive PD-L1 status for the SP142 clone related with improved overall survival in oropharyngeal squamous cell carcinoma. Tumors heavily infiltrated by tumor infiltrating lymphocytes were also linked with better outcome, and this as well for the total number of tumor infiltrating lymphocytes as for the CD3⁺ and CD8⁺ T cell count. A Cox proportional hazard model proved that solely infiltrating CD8⁺ T cells exhibit a positive effect on overall survival (hazard ratio = 0.31 [0.14–0.70]; P = 0.0050)

Materials and Methods

Formalin-fixed, paraffin-embedded tissue from oropharyngeal tumors of 99 patients was immunohistochemically stained for PD-L1 (SP142 and 22C3 clones), CD3, CD8 and FoxP3. Expression of PD-L1, CD3, CD8, FoxP3 and HPV status were correlated with clinicopathological variables. Overall survival was determined by a log-rank (Mantel–Cox) test whereas the Cox proportional hazard model was used for multivariate analysis.

Conclusions

Our results demonstrate that CD8⁺ T lymphocytes constitute an independent prognostic marker in patients diagnosed with oropharyngeal squamous cell carcinoma. PD-L1 positivity for SP142, but not for 22C3, also tends to have a positive effect on survival in oropharyngeal squamous cell carcinoma.