Immuno-oncology in head and neck squamous cell cancers: News from clinical trials, emerging predictive factors and unmet needs

PD-L1 expression in recurrent or metastatic head and neck squamous cell carcinoma in China (EXCEED study): a multicentre retrospective study

AIMS

Programmed death-ligand 1 (PD-L1) is known to be highly expressed in various malignancies, including head and neck squamous cell carcinoma (HNSCC). We aimed to determine the prevalence of PD-L1 expression in recurrent or metastatic HNSCC (R/M HNSCC) among Chinese patients.

METHODS

This multicentre, retrospective analysis of data from six centres in China included patients with R/M HNSCC treated from 9 August 2021 to 28 February 2022. PD-L1 expression in tumour tissue was assessed and represented using a combined positive score (CPS). The χ2 and Cochran-Mantel-Haenszel χ2 tests were used to compare the prevalence of different PD-L1 expression statuses according to related co-variables.

RESULTS

For all 402 examined patients with R/M HNSCC, 168 cases (41.8%) had PD-L1 expression with a CPS ≥20, and 337 cases (83.8%) had PD-L1 expression with a CPS ≥1. Between the PD-L1 CPS ≥20 group and PD-L1 CPS <20 group, statistically significant differences were observed for variables of sex (p<0.001), smoking habit (p=0.0138 for non-smokers vs current smokers) and primary tumour site (p<0.001 for hypopharynx vs oral cavity and p=0.0304 for larynx vs oral cavity, respectively).

CONCLUSION

PD-L1 with CPS ≥20 was expressed in about 41.8% of cases with R/M HNSCC among Chinese patients, and PD-L1 expression was significantly associated with sex, smoking history and primary tumour site. Our findings regarding the variables related to PD-L1 expression level provide insight for clinical practice and a solid basis for future research on immunotherapy in HNSCC.

TRIAL REGISTRATION NUMBER

ISRCTN10570964.

Stabilization of EREG via STT3B-mediated N-glycosylation is critical for PDL1 upregulation and immune evasion in head and neck squamous cell carcinoma

Dysregulated Epiregulin (EREG) can activate epidermal growth factor receptor (EGFR) and promote tumor progression in head and neck squamous cell carcinoma (HNSCC). However, the mechanisms underlying EREG dysregulation remain largely unknown. Here, we showed that dysregulated EREG was highly associated with enhanced PDL1 in HNSCC tissues. Treatment of HNSCC cells with EREG resulted in upregulated PDL1 via the c-myc pathway. Of note, we found that N-glycosylation of EREG was essential for its stability, membrane location, biological function, and upregulation of its downstream target PDL1 in HNSCC. EREG was glycosylated at N47 via STT3B glycosyltransferases, whereas mutations at N47 site abrogated N-glycosylation and destabilized EREG. Consistently, knockdown of STT3B suppressed glycosylated EREG and inhibited PDL1 in HNSCC cells. Moreover, treatment of HNSCC cells with NGI-1, an inhibitor of STT3B, blocked STT3B-mediated glycosylation of EREG, leading to its degradation and suppression of PDL1. Finally, combination of NGI-1 treatment with anti-PDLl therapy synergistically enhanced the efficacy of immunotherapy of HNSCC in vivo. Taken together, STT3B-mediated N-glycosylation is essential for stabilization of EREG, which mediates PDL1 upregulation and immune evasion in HNSCC.

Increased tumor-infiltrating plasmacytoid dendritic cells express high levels of PD-L2 and affect CD8+ T lymphocyte infiltration in human laryngeal squamous cell carcinoma

The infiltration and prognostic significance of tumor-infiltrating plasmacytoid dendritic cells (TI-pDC) have been elucidated in various human solid cancers. However, the infiltrating patterns and functional importance of TI-pDC in laryngeal squamous cell carcinoma (LSCC) remain unknown. In this study, flow cytometric analyses were conducted to characterize the infiltration of dendritic cells and T lymphocytes, along with their respective subgroups in tumor tissues (TT), para-carcinoma tissues (PT), and peripheral blood (PB) from LSCC patients. Immunohistochemical staining for CD4 and CD8, as well as immunofluorescence staining for CD123, were performed on serial tissue sections to investigate the co-localization of TI-pDC and tumor-infiltrating T lymphocytes (TIL) within the tumor microenvironment (TME). Our results demonstrated significantly lower percentages of all three DC subsets in PB compared to TT and PT. Notably, the pDC percentage was markedly higher in TT than in PT. Moreover, TI-pDC percentage was significantly elevated in N+ stage patients compared to those with N0 stage. The results of survival analysis consistently demonstrated that high levels of TI-pDC infiltration were indicative of a poor prognosis. Further investigation revealed a significant negative correlation between TI-pDC and CD8+ TILs; notably, pDCs expressed an inhibitory surface molecule PD-L2 rather than PD-L1 within PT. Collectively, our findings suggest that increased TI-pDC is associated with adverse outcomes in LSCC patients while exhibiting an inhibitory phenotype that may play a crucial role in suppressing CD8+ TILs within LSCC tumors. These results highlight the potential therapeutic strategy targeting PD-L2+ pDCs for immunotherapies against LSCC.

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.

Prognostic role of PD-L1 expression in head and neck squamous cell carcinoma: An institutional experience from India

BACKGROUND

Squamous cell carcinoma accounts for > 90% of Head and neck cancers and has a poor 5-year survival rate of only 50%. Immunosuppressive agents like PD-L1 inhibitors have been found to improve survival in many tumour types, including advanced/recurrent head and neck squamous cell carcinoma (HNSCC). The PD-L1 expression in this tumour can also predict clinical outcome. However, this fact still remains to be proven.

AIM

The aim was to study the expression of PD-L1 in HNSCC, correlate with clinicopathological parameters and outcome.

MATERIAL AND METHOD

This prospective study was conducted between March 2021 to June 2023 in department of Pathology of a tertiary care centre located in northern India. A total of 65 histologically confirmed cases of HNSCC were included. Expression of PD-L1 was determined by immunohistochemistry. The combined positive (CPS) and tumour proportion (TP) scores were calculated. The results were correlated with clinicopathological parameters and outcome using appropriate statistical tools.

RESULTS

Considering CPS, 42 (64.6%) cases showed expression of PD-L1. A high score of ≥ 20% was seen in 10 cases (15.4%). PD-L1 expression did not correlate with any of the clinical parameters including age, gender, addiction, site, TNM stage and HPV status. Conventional HNSCC had significantly higher expression of PD-L1. The cases with positive PD-L1 expression had a higher mean survival and a lower mortality, but the difference was not statistically significant.

CONCLUSION

PD-L1 expression is more likely to be seen in conventional HNSCC histomorphology. PD-L1 expression is a predictor of better prognosis in HNSCC.

Depth of response may predict clinical outcome in patients with recurrent/metastatic head and neck cancer treated with pembrolizumab-containing regimens

Background

Pembrolizumab-containing regimens are standards of care for recurrent and metastatic head and neck squamous cell carcinoma (R/M HNSCC). The depth of response (DpR) predicts the survival of patients with several types of solid cancers; however, its association with the survival outcomes of patients with R/M HNSCC treated with pembrolizumab-containing regimens remains unclear.

Methods

This study included 66 patients with R/M HNSCC who received a pemblolizumab-containing regimen as a first-line therapy at Tohoku University Hospital, Sendai, Japan. The patients' characteristics, combined positive score, baseline tumor size, tumor response, DpR, overall survival (OS), progression-free survival (PFS), PFS2, and adverse events were reviewed. The associations between DpR and survival outcomes were analyzed.

Results

The 1 year-OS and 1 year-PFS rates of pembrolizumab-containing regimens were 69.4% and 24.4%, respectively. The response rate was 28.8%. The mean and median values of tumor change from baseline were 5.1% and -9.0%. In the correlation analysis, a significant negative correlation was observed between tumor change rate from baseline and survival outcomes (OS: r= -0.41, p=0.0017; PFS: r=-0.49, p<0.001). In the multivariate analysis, DpR with tumor change of ≤-45 was associated with better OS and PFS.

Conclusion

DpR induced by pembrolizumab-containing regimens may be a predictive factor for OS and PFS in patients with R/M HNSCC.

Role of Surgical Pathologist for Detection of Immunooncologic Predictive Factors in Head and Neck Cancer

Immunotherapy has shown promising results in the treatment of recurrent and metastatic head and neck cancers. Antiprogrammed cell death (PD)-1 therapies have been recently approved in this setting and they are currently tested also in the treatment of locally advanced diseases and in the neoadjuvant setting. However, the clinical benefits of these treatments have been quite variable, hence the need to select those patients who may obtain the maximal efficacy through the identification of predictive biomarkers. Currently, PD-L1 immunohistochemical expression by tumor and immune cells is the most widely used predictive biomarker for immunotherapy in head and neck squamous cell carcinoma. Nevertheless, patients with PD-L1 - tumors may still respond to treatments, thereby emphasizing the need for the identification of other predictive biomarkers. In this review, we summarize the current data on histologic and molecular parameters that can be used to select patients with head and neck cancers for immunotherapy, with a focus on squamous cell carcinoma and salivary gland carcinomas.

Role of Adenoviruses in Cancer Therapy

Cancer is one of the leading causes of death in the world, which is the second after heart diseases. Adenoviruses (Ads) have become the promise of new therapeutic strategy for cancer treatment. The objective of this review is to discuss current advances in the applications of adenoviral vectors in cancer therapy. Adenoviral vectors can be engineered in different ways so as to change the tumor microenvironment from cold tumor to hot tumor, including; 1. by modifying Ads to deliver transgenes that codes for tumor suppressor gene (p53) and other proteins whose expression result in cell cycle arrest 2. Ads can also be modified to express tumor specific antigens, cytokines, and other immune-modulatory molecules. The other strategy to use Ads in cancer therapy is to use oncolytic adenoviruses, which directly kills tumor cells. Gendicine and Advexin are replication-defective recombinant human p53 adenoviral vectors that have been shown to be effective against several types of cancer. Gendicine was approved for treatment of squamous cell carcinoma of the head and neck by the Chinese Food and Drug Administration (FDA) agency in 2003 as a first-ever gene therapy product. Oncorine and ONYX-015 are oncolytic adenoviral vectors that have been shown to be effective against some types of cancer. The Chiness FDA agency has also approved Oncorin for the treatment of head and neck cancer. Ads that were engineered to express immune-stimulatory cytokines and other immune-modulatory molecules such as TNF-α, IL-2, BiTE, CD40L, 4-1BBL, GM-CSF, and IFN have shown promising outcome in treatment of cancer. Ads can also improve therapeutic efficacy of immune checkpoint inhibitors and adoptive cell therapy (Chimeric Antigen Receptor T Cells). In addition, different replication-deficient adenoviral vectors (Ad5-CEA, Ad5-PSA, Ad-E6E7, ChAdOx1-MVA and Ad-transduced Dendritic cells) that were tested as anticancer vaccines have been demonstrated to induce strong antitumor immune response. However, the use of adenoviral vectors in gene therapy is limited by several factors such as pre-existing immunity to adenoviral vectors and high immunogenicity of the viruses. Thus, innovative strategies must be continually developed so as to overcome the obstacles of using adenoviral vectors in gene therapy.

Characterization of the tumor immune microenvironment of sinonasal squamous-cell carcinoma

BACKGROUND

Treatment and prognosis of sinonasal squamous-cell carcinoma (SNSCC) have not significantly improved despite improvements in radical therapy. Characterization of the tumor immune microenvironment (TiME) may identify patient subgroups associated with disease recurrence, and provide new biomarkers for improved patient stratification and treatment.

METHODS

The TiME was quantitatively evaluated by multiplex immunohistochemistry (mIHC) in archived tissue sections from 38 patients with SNSCC, and were assessed for differences between recurrent (n = 20) and nonrecurrent (n = 18) groups. Hierarchical clustering analyses were performed to identify phenotypic TiME subgroups within the cohort and were used to compare survival outcomes.

RESULTS

Our mIHC analysis revealed increased T-cell populations and decreased myeloid-cell populations in SNSCC patients without recurrent disease, as compared with patients with recurrent disease. Within T-cell subsets, there was a significantly higher percentage of granzyme B⁺ , T-bet⁺ , Eomes⁺ T cells, as well as higher proliferation of CD8⁺ T cells within the nonrecurrent group relative to the recurrent group. Furthermore, immune-cell complexity profiles of SNSCC revealed hyper- and hypo-T-cell-inflamed, myeloid-inflamed, B-cell-inflamed, and broadly hypoinflamed subtypes not previously identified by gene expression analyses. Our study revealed that presence of either hyper- or hypo-T-cell-inflamed TiME subtypes were associated with increased survival outcomes as compared with broadly hypoinflamed TiME subtypes (p = 0.035 and 0.0376, respectively).

CONCLUSIONS

The TiME of SNSCC reveals distinct subtypes, which may correlate with recurrence and survival outcomes.

Differential Expression of PD-L1 during Cell Cycle Progression of Head and Neck Squamous Cell Carcinoma

The expression of PD-L1 by tumor cells is mainly associated with its immunosuppressive effect. In fact, PD-1/PD-L1 immune checkpoint inhibitors demonstrated remarkable effects in advanced cancer patients including HNSCC. In this context, irradiation is currently being investigated as a synergistic treatment modality to immunotherapy. However, the majority of HNSCC patients still show little improvement or even hyperprogression. Interestingly, there is increasing evidence for additional cell-intrinsic functions of PD-L1 in tumor cells. In previous studies, we showed that PD-L1 has a strong influence on proliferation, migration, invasion, and survival after irradiation. We demonstrated that cellular expression and localization of PD-L1 differed depending on sensitivity to irradiation. Here, we show that PD-L1 is also differentially expressed during cell cycle progression of HNSCC. Furthermore, cellular localization of PD-L1 also changes depending on a particular cell cycle phase. Moreover, distinct observations occurred depending on the general differentiation status. Overall, the function of PD-L1 cannot be generalized. Rather, it depends on the differentiation status and microenvironment. PD-L1 expression and localization are variable, depending on different factors. These findings may provide insight into why differential response to PD-1/PD-L1 antibody therapy can occur. Detailed understanding of cell-intrinsic PD-L1 functions will further allow antibody-based immunotherapy to be optimized.

Identification of factors related to immunotherapy efficacy and prognosis in patients with advanced head and neck squamous cell carcinoma

BACKGROUND

Immunotherapy is an important treatment in oncology, but only a fraction of patients with head and neck squamous cell carcinoma (HNSCC) benefit from it. Therefore, the aim of this study was to identify predictive biomarkers of immunotherapy response for HNSCC in order to improve treatment outcomes.

METHODS

Survival analyses and comparative efficacy evaluation were performed to investigate prognostic and therapeutic impact factors in patients with advanced HNSCC following immunotherapy, and to examine the effects of factors including gene mutations, tumor mutational burden (TMB), mutant-allele tumor heterogeneity (MATH), and immune cell infiltration on the survival and efficacy.

RESULTS

Anti-PD-1 treatment led to a prolonged overall survival (OS) in HNSCC patients with gene mutations compared with those without the mutations, while no significant difference in the OS was found between the two groups of patients. And no marked association between the MATH value and OS was detected in HNSCC patients, whereas patients with either high TMB scores in tissues and blood or high immune cell infiltration displayed a significantly longer OS. Further analysis with efficacy as the primary endpoint revealed no significant differences in the tissue TMB, blood TMB, and MATH value between the patients who responded to immunotherapy and those who did not. Moreover, no significant differences in the expression percentages of positive immune cells in tumor, stroma, and total regions were identified between the above two groups of patients.

CONCLUSION

HNSCC is characterized by high mutation rate, high mutation burden, and high level of immune cell infiltration, and a subset of HNSCC patients respond to immunotherapy. Here, we showed that high mutation burden and immune cell infiltration may improve the prognosis of HNSCC patients with immunotherapy, while there was no remarkable effect on the efficacy.

Immune deserts in head and neck squamous cell carcinoma: A review of challenges and opportunities for modulating the tumor immune microenvironment

Immunotherapy revolutionized cancer treatment but has yet to elicit durable responses in the majority of patients with head and neck squamous cell carcinoma (HNSCC). HNSCC is generally characterized by a high tumor mutational burden, which has translated to a large neoantigen load that could prime the immune system to recognize and eliminate malignant cells. Studies are increasingly showing, however, that HNSCC is an "immune desert" tumor that can hijack multiple parts of the tumor immunity cycle in order to evade immune recognition and suppress immune system activation. Herein we will review how HNSCC tumors modulate their architecture, cellular composition, and cytokine milieu to maximize immunosuppression; as well as relevant therapeutic opportunities and emerging issues facing the field of HNSCC immuno-oncology.

Diagnostic and Predictive Role of DLL3 Expression in Gastroenteropancreatic Neuroendocrine Neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are a rare and heterogeneous subgroup of tumors with a challenging management because of their extremely variable biological and clinical behaviors. Due to their different prognosis, there is an urgent need to identify molecular markers which would enable to discriminate between grade 3 neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs), despite both being diagnosed mainly on the basis of proliferation index and cell differentiation. DLL3, a negative Notch regulator, is a promising molecular target highly expressed in several tumors with neuroendocrine features. We conducted a retrospective analysis of DLL3, RB1, and PD-L1 expression by immunohistochemistry (IHC), in formalin-fixed, paraffin-embedded (FFPE) samples from 47 patients with GEP-NENs. Then, we correlated the results with patients' clinical features and outcome. The absence of DLL3 expression in 5 well-differentiated GEP-NETs with high-grade features (G3 NET), and the presence of DLL3 in 76.9% of poorly-differentiated NECs (G3 NEC), highlights DLL3 expression as a marker of G3 NECs (p = 0.007). DLL3 expression was correlated with RB1-loss (p < 0.001), negative ⁶⁸ Ga-PET/CT scan (p = 0.001), and an unfavorable clinical outcome, with important implications for treatment response and patient's follow-up. Median progression-free survival (PFS) and overall survival (OS) were 22.7 months (95% CI 6.1-68.8) and 68.8 months (95% CI 26.0-78.1), respectively, in patients with DLL3-negative tumor compared with 5.2 months (95% CI 2.5-18.5) and 9.5 months (95% CI 2.5-25.2), respectively, in patients with DLL3-positive tumor (PFS p = 0.0083, OS p = 0.0071). Therefore, combined with morphological cell analysis, DLL3 could represent a valuable histological marker, for the diagnosis of poorly differentiated NECs. The high percentage of DLL3 expression in NEC patients also highlights a potential opportunity for a DLL3 targeted therapy in this tumor subset.

Tumor Microenvironment, HLA Class I and APM Expression in HPV-Negative Oral Squamous Cell Carcinoma

Simple Summary

Oral squamous cell carcinoma has developed different strategies to escape from T-cell-mediated immune surveillance, which is mediated by changes in the composition of cellular and soluble components of the tumor microenvironment as well as an impaired expression of molecules of the antigen processing machinery leading to a downregulation of HLA class I surface antigens. In depth characterization of these escape mechanisms might help to develop strategies to overcome this tolerance. In this study, human papilloma virus negative oral squamous cell carcinoma lesions were analyzed regarding the protein expression of major components of the HLA class I antigen processing/presentation pathway in correlation to the intra-tumoral immune cell composition, IFN-γ signaling and clinical parameters, which was further confirmed by bioinformatics analyses of datasets obtained from The Cancer Genome Atlas. This novel knowledge could be used for optimizing the design of immunotherapeutic approaches of this disease.

Abstract

Progression of oral squamous cell carcinoma (OSCC) has been associated with an escape of tumor cells from the host immune surveillance due to an increased knowledge of its underlying molecular mechanisms and its modulation by the tumor microenvironment and immune cell repertoire. In this study, the expression of HLA class I (HLA-I) antigens and of components of the antigen processing machinery (APM) was analyzed in 160 pathologically classified human papilloma virus (HPV)-negative OSCC lesions and correlated to the intra-tumoral immune cell response, IFN-γ signaling and to the patient’s outcome. A heterogeneous but predominantly lower constitutive protein expression of HLA-I APM components was found in OSCC sections when compared to non-neoplastic cells. Tumoral HLA-I APM component expression was further categorized into the three major phenotypes HLA-I^high/APM^high, HLA-I^low/APM^low and HLA-I^{discordant high/low}/APM^high. In the HLA-I^high/APM^high group, the highest frequency of intra-tumoral CD8⁺ T cells and lowest number of CD8⁺ T cells close to FoxP3⁺ cells were found. Patients within this group presented the most unfavorable survival, which was significantly evident in stage T2 tumors. Despite a correlation with the number of intra-tumoral CD8⁺ T cells, tumoral JAK1 expression as a surrogate marker for IFN-γ signaling was not associated with HLA-I/APM expression. Thus, the presented findings strongly indicate the presence of additional factors involved in the immunomodulatory process of HPV-negative OSCC with a possible tumor-burden-dependent complex network of immune escape mechanisms beyond HLA-I/APM components and T cell infiltration in this tumor entity.

PD-L1 expression in the microenvironment and the response to checkpoint inhibitors in head and neck squamous cell carcinoma

In head and neck squamous cell carcinoma (HNSCC), data from studies using checkpoint-inhibiting antibodies that target programmed death 1 (PD-1) or its ligand the programmed death ligand 1 (PD-L1) demonstrated outstanding clinical activity. Translational investigations also suggested some correlations between therapeutic response and PD-L1 expression in tumor tissue. We comprehensively summarize results that have evaluated PD-L1 expression in HNSCC. We discuss flaws and strength of current PD-1/PD-L1 detection, quantification methods and the evaluation of PD-L1 as a prognostic and theragnostic biomarker. Understanding tumor microenvironment may help understanding resistance to checkpoint inhibitors, designing clinical trials that can exploit drug combinations.

An assessment of racial differences in epidemiological, clinical and psychosocial factors among head and neck cancer patients at the time of surgery

Objective

Racial disparities have been well characterized and African American (AA) patients have 30% lower 5-year survival rates than European Americans (EAs) for head and neck squamous carcinoma (HNSCC). This poorer survival can be attributed to a myriad of different factors. The purpose of this study was to characterize AA-EA similarities and differences in sociodemographic, lifestyle, clinical, and psychosocial characteristics in HNSCC patients near the time of surgery.

Methods

Setting: Single tertiary care center. Participants: Thirty-nine newly diagnosed, untreated HNSCC patients (n = 24 EAs,n = 15 AAs) who were to undergo surgery were recruited. Study Design: Cross-sectional study Sociodemographic, lifestyle factors, and disease factors (cancer site, AJCC clinical and pathologic stage, and HPV status)were assessed. Risk factors, leisure time, quality of life and social support were also assessed using validated questionnaires. Exposures: EA and AA patients were similar in the majority of sociodemographic factors assessed. AAs had a higher trend toward pathologically later stage disease compared to EAs and significantly increased time to treatment.

Results

EA and AA patients were similar in the majority of sociodemographic factors assessed. AAs had a higher trend toward pathologically later stage disease compared to EAs. AAs also had significantly increased time to treatment (P = 0.05). The majority of AA patients (62%) had later stage pathologic disease. AA were less likely to complete high school or college (P = 0.01) than their EA counterparts. Additionally, AAs were more likely to report having a gap in health insurance during the past decade (37% vs. 15%).

Conclusions

This preliminary study demonstrates a similar profile of demographics, clinical and psychosocial characteristics preoperatively for AAs and EAs. Key differences were AAs tending to have later pathologic stage disease, educational status, delays in treatment initiation, and gaps in health insurance.

The Microenvironment of Head and Neck Cancers: Papillomavirus Involvement and Potential Impact of Immunomodulatory Treatments

Cancer progression can be understood as the result of deregulation of tumors' immune microenvironments. Recent studies of the alterations of microenvironments highlight their significant influence on the prognosis of patients with head and neck squamous cell carcinoma (HNSCC). It is necessary to better characterize tumor-infiltrating lymphocytes by focusing, in particular, on the tumor escape mechanisms from immune surveillance. One of the best described tumor immune system evasion mechanisms is the expression of co-stimulation molecules that constitute so-called "immune checkpoints". These molecules regulate the immune response by either activating or inhibiting its effects. The programmed cell death 1 (PD-1) surface protein is an inhibitory co-stimulation molecule that induces exhaustion of activated T-lymphocytes (TLs, T cells) through binding with its ligands, PD-L1 and PD-L2. Half of HNSCCs exhibit PD-L1 expression with higher expression identified in human papillomavirus (HPV) positive tumors. Numerous studies have shown differences between the microenvironments of HPV+ and HPV- cancers. Notably, infiltrations of exhausted CD4+ PD1+ and CD8+ PD1+ T cells are far higher in the microenvironment of HPV+ tumors. The FDA has approved the use of molecules that target PD-1 for the treatment of HNSCC. The first results of clinical trials with anti-PD-1 blockers in HNSCC show improved patient survival, particularly long-term survival without recurrence. However, discordant results were sometimes observed, and improvements in defining cellular predictive markers are necessary. With the development of immunotherapies, pathologists play a role in the selection of patients who are eligible for specific treatments and assessment of their prognosis in greater detail. An automated, quantitative in situ imaging system that integrates both multispectral imaging and automated slide scanning could be developed in pathology laboratories. The evaluation of PD-L1 expression has only been used to stratify the administration of first-line immunotherapy. The validation of these tests and their routine interpretation is essential. No specific recommendation is adopted for HPV+ HNSCC.

Immunotherapies and Future Combination Strategies for Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is often diagnosed at an advanced stage and has a dismal prognosis. Nearly 10 years after the approval of cetuximab, anti-PD1/PD-L1 checkpoint inhibitors are the first drugs that have shown any survival benefit for the treatment on platinum-refractory recurrent/metastatic (R/M) HNSCC. Furthermore, checkpoint inhibitors are better tolerated than chemotherapy. The state of the art in the treatment of R/M HNSCC is changing, thanks to improved results for checkpoint inhibitors. Results for these treatments are also awaited in curative settings and for locally advanced HNSCC. Unfortunately, the response rate of immunotherapy is low. Therefore, the identification of predictive biomarkers of response and resistance to anti-PD1/PD-L1 is a key point for better selecting patients that would benefit the most from immunotherapy. Furthermore, the combination of checkpoint inhibitors with various agents is being currently evaluated to improve the response rate, prolong response duration, and even increase the chances for a cure. In this review, we summarize the most important results regarding immune targeting agents for HNSCC, predictive biomarkers for resistance to immune therapies, and future perspectives.

Accelerated elimination of human cancer cells by a CD40 agonist antibody combined with a PD-1 antagonist in CD4-depleted mice

The elimination of residual microscopic cancer cells is important cancer treatment. The immunoediting theory describes the balance between the immune system and cancer cells. The current study investigated changes in the immune system during the elimination of cancer cells and evaluated the influence of cluster of differentiation (CD)4 or CD8 depletion. A human squamous cell cancer cell line (SNU1041) was injected in the lateral tongue of immunocompetent mice and the changes in the CD4, CD8, CD11b, CD19, CD40 and CD40 ligand (L) populations in the blood, lymph nodes and spleen were evaluated using flow cytometry, and changes in serum cytokine levels were evaluated using a magnetic bead panel. Cancer cell elimination was delayed by CD4 depletion but not by CD8 depletion. The CD8-depleted group indicated increased levels of CD40L, interferon-gamma, interleukin (IL)-10, IL-6, and tumor necrosis factor-α. It was concluded that CD4 served a crucial role in the elimination of human cancer cells. Furthermore, the efficacies of CD40 agonist and programmed cell death protein 1 (PD1) antagonist treatments were assessed in CD4-depleted mice. CD40 agonist treatment resulted in faster cancer cell elimination and increased cytokine excretion. In conclusion, CD4 or CD40L significantly influenced cancer elimination. CD40 agonist antibodies may be potent adjuvant agents that can be used in patients with reduced CD4 or CD40L expression.

Clinical relevance and significance of programmed death-ligand 1 expression, tumor-infiltrating lymphocytes, and p16 status in sinonasal squamous cell carcinoma

Purpose: Immunotherapy may be a potential alternative for patients with sinonasal squamous cell carcinoma (SNSCC). Data regarding potential immunotherapy targets, such as programmed death-ligand 1 (PD-L1) and tumor-infiltrating lymphocytes (TILs), in SNSCC are limited. In this study, we assessed the prevalence and prognostic value of PD-L1 expression and TILs in p16-negative and p16-positive SNSCC. Patients and methods: Tissues from 96 patients with SNSCC were stained using immunohistochemistry against PD-L1, CD8, and Foxp3 to assess the immune environment. The correlations between PD-L1 expression, TILs, and p16 status were analyzed. Additionally, PD-L1, CD8, and Foxp3 expressions, as well as p16 status, were analyzed in relation to patient clinicopathological variables and prognosis. Results: Twenty-nine (30.2%) patients with SNSCC showed PD-L1 expression in >5% of tumor cells. PD-L1 expression was significantly correlated with poor differentiation and a high level of TILs. PD-L1 expression and the CD8+ and Foxp3+ T-cell infiltrates in p16-negative patients (n=78, 81.2%) and p16-positive patients (n=18, 18.8%) were not significantly different. PD-L1 expression and p16 status were not associated with overall survival (OS) and disease-free survival (DFS). Patients with high CD8+ or Foxp3+ cell infiltration had better clinical outcomes. A multivariate analysis confirmed that CD8 TILs were a significant independent and favorable prognostic factor for OS (p=0.023) and DFS (p=0.008). Conclusion: TILs can play a prognostic role in SNSCC. We did not find differences in immune marker expression between p16-positive and p16-negative SNSCC tissues. The high correlation between PD-L1 expression and TILs indicates that the PD-1/PD-L1 pathway is a promising immunotherapeutic target for SNSCC.

Heterogeneity of the Head and Neck Squamous Cell Carcinoma Immune Landscape and Its Impact on Immunotherapy

Head and neck squamous cell carcinomas (HNSCCs) are highly aggressive, multi-factorial tumors in the upper aerodigestive tract affecting more than half a million patients worldwide each year. Alcohol, tobacco, and human papillomavirus (HPV) infection are well known causative factors for HNSCCs. Current treatment options for HNSCCs are surgery, radiotherapy, chemotherapy, or combinatorial remedies. Over the past decade, despite the marked improvement in clinical outcome of many tumor types, the overall 5-year survival rate of HNSCCs remained ∼40–50% largely due to poor availability of effective therapeutic options for HNSCC patients with recurrent disease. Therefore, there is an urgent and unmet need for the identification of specific molecular signatures that better predict the clinical outcomes and markers that serve as better therapeutic targets. With recent technological advances in genomic and epigenetic analyses, our knowledge of HNSCC molecular characteristics and classification has been greatly enriched. Clinical and genomic meta-analysis of multicohort HNSCC gene expression profile has clearly demonstrated that HPV⁺ and HPV^- HNSCCs are not only derived from tissues of different anatomical regions, but also present with different mutation profiles, molecular characteristics, immune landscapes, and clinical prognosis. Here, we briefly review our current understanding of the biology, molecular profile, and immunological landscape of the HPV⁺ and HPV^- HNSCCs with an emphasis on the diversity and heterogeneity of HNSCC clinicopathology and therapeutic responses. After a review of recent advances and specific challenges for effective immunotherapy of HNSCCs, we then conclude with a discussion on the need to further enhance our understanding of the unique characteristics of HNSCC heterogeneity and the plasticity of immune landscape. Increased knowledge regarding the immunological characteristics of HPV⁺ and HPV^- HNSCCs would improve therapeutic targeting and immunotherapy strategies for different subtypes of HNSCCs.

Predictive biomarkers for PD-1 and PD-L1 immune checkpoint blockade therapy

The immune system is very important for monitoring and eradicating cancer cells. However, there may be multiple immunosuppressive mechanisms to prevent effective antitumor immunity in the tumor environment, such as the negative immunologic regulators known as checkpoints. Antibodies that block the checkpoints programmed cell death protein 1 (PD-1) pathway have made great success. Nevertheless, the response rates are likely to vary widely. Therefore, several researches are currently underway to determine which biomarkers are able to identify the group of patients who can obtain benefits from PD-1 and programmed cell death-ligand 1 (PD-L1) immune checkpoint blockade therapy. This review focuses on potential predictive biomarkers for PD-1/PD-L1 checkpoint blockade immunotherapy in order to provide advice and guidance for clinical treatment.

Immune Evasion by Head and Neck Cancer: Foundations for Combination Therapy

Head and neck cancer is disfiguring and deadly, and contemporary treatment has fallen short in terms of morbidity and mortality. The rich immune infiltrate within these tumors designates them as prime candidates for immunotherapy and success with these drugs has been documented for recurrent and metastatic head and neck cancer. Still, single-agent immunotherapy has generated either only transient responses or durable response in only a minority subset of patients. Mapping the immune escape mechanisms enacted by head and neck cancer within the tumor microenvironment allows for rational design of strategies to overcome this tolerance. We outline the immune pathway derangements within the head and neck cancer microenvironment and discuss combination treatment strategies to overcome the limitations of immunologic monotherapy.

Not CD68 but stabilin-1 expression is associated with the risk of recurrence in patients with oral cavity squamous cell carcinoma

BACKGROUND

This study's aim was to identify CD68 and stabilin-1 expressions and their prognostic implications in patients with oral cavity cancer (OCC).

METHODS

Stabilin-1 and CD68 immunochemical staining was conducted in samples from patients with OCC who underwent curative surgery in our institute. We retrospectively analyzed patients' clinical information. We investigated the relationship between CD68 and stabilin-1 expression levels and their effect on prognostic factors and survival.

RESULTS

Fifty-four patients' data were analyzed. CD68 and stabilin-1 expressions were positively correlated (P = .008). CD68 and stabilin-1 expressions were not correlated with other prognostic factors (eg, T classification or lymph node metastasis). Stabilin-1 expression and tumor recurrence risk were positively correlated (P = .015). CD68 expression was neither associated with recurrence-free nor OCC-specific survival.

CONCLUSION

CD68 and stabilin-1 expressions in OCC were positively correlated. Stabilin-1 expression was significantly associated with OCC recurrence risk, but the prognostic value of CD68 was not confirmed.

An update: emerging drugs to treat squamous cell carcinomas of the head and neck

Introduction: Subsequent to the 2006 FDA approval of cetuximab, a variety of molecular targeting agents have been evaluated in head and neck squamous cell carcinoma (HNSCC). The treatment outcomes of recurrent and/or metastatic (R/M) HNSCC, in particular, remain dismal. The 2016 FDA approval of PD-1 immune checkpoint inhibitors has expanded the treatment options for R/M HNSCC and highlights the potential for immune-based therapies. Areas covered: We will review the clinical application of EGFR-targeted agents, alone and in combination with other drugs. Molecular targeting agents directed against the IL6/PI3K/STAT3 signaling pathway will be covered. In addition, evaluation of immune checkpoint inhibitors in HNSCC, along with ongoing combination trials incorporating these agents, will be discussed. The expanded indications of emerging drugs and the potential clinical benefit of new drugs and treatment combinations will be summarized. Expert opinion: In recent years, there has been a major shift toward immunotherapy-based approaches for the treatment of HNSCC, leading to significant improvements in outcomes for a subset of patients. Leveraging the increased understanding of the genetic alterations that characterize individual HNSCC tumors will facilitate precision medicine approaches using targeted agents, immunotherapies, as well as standard chemotherapy and radiation.

Crosstalk Between PD-1/PD-L1 Blockade and Its Combinatorial Therapies in Tumor Immune Microenvironment: A Focus on HNSCC

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy worldwide with a poor prognosis and high mortality. More than two-thirds of HNSCC patients still have no effective control of clinical progression, and the five-year survival rate is < 50%. Moreover, patients with platinum-refractory HNSCC have a median survival of < 6 months. The significant toxicity and low survival rates of current treatment strategies highlight the necessity for new treatment modalities. Recently, a large number of studies have demonstrated that programmed cell death protein-1 (PD-1) and its ligand, programmed cell death protein ligand-1 (PD-L1) play an essential role in tumor initiation and progression. PD-1/PD-L1 blockade has shown a desired and long-lasting therapeutic effect in the treatment of HNSCC and other malignancies. However, only a small number of patients with HNSCC can benefit from PD-1/PD-L1 blockade monotherapy, while the majority of patients do not respond. To overcome the unsatisfactory therapeutic effect of PD-1/PD-L1 blockade monotherapy, combining other treatment options for HNSCC (including chemotherapy, radiotherapy, targeted therapy, and immunotherapy) in the treatment scheme has become a commonly used strategy. Herein, the potential mechanisms underlying the crosstalk between PD-1/PD-L1 blockade and its combinatorial therapies for HNSCC were reviewed, and it is hoped that the improved understanding of the crosstalk process would provide further ideas for the design of a combinatorial regimen with a higher efficiency and response rate for the treatment of HNSCC and other malignancies.