The Tumor-Specific Immune Landscape in HPV+ Head and Neck Cancer

Type I conventional dendritic cells and CD8+ T cells predict favorable clinical outcome of head and neck squamous cell carcinoma patients

Head and neck squamous cell carcinoma (HNSCC) is one of the most common tumor entities worldwide, with human papillomavirus (HPV) infection contributing to cancer development. Conventional therapies achieve only limited efficiency, especially in recurrent or metastatic HNSCC. As the immune landscape decisively impacts the survival of patients and treatment efficacy, this study comprehensively investigated the immunological tumor microenvironment (TME) and its association with patient outcome, with special focus on several dendritic cell (DC) and T lymphocyte subpopulations. Therefore, formalin-fixed paraffin-embedded tumor samples of 56 HNSCC patients, who have undergone resection and adjuvant radiotherapy, were analyzed by multiplex immunohistochemistry focusing on the detailed phenotypic characterization and spatial distribution of DCs, CD8+ T cells, and T-helper cell subsets in different tumor compartments. Immune cell densities and proportions were correlated with clinical characteristics of the whole HNSCC cohort and different HPV- or hypoxia-associated subcohorts. Tumor stroma was highly infiltrated by plasmacytoid DCs and T lymphocytes. Among the T-helper cells and CD8+ T cells, stromal regulatory T cells and intraepithelial exhausted CD8+ T cells expressing programmed cell death protein-1 (PD-1+) and/or lymphocyte-activation gene-3 (LAG-3+) were the predominant phenotypes, indicating an immunosuppressive TME. HPV-associated tumors showed significantly higher infiltration of type I and type II conventional DCs (cDC1, cDC2) as well as several CD8+ T cell phenotypes including exhausted, activated, and proliferating T cells. On the contrary, tumors with hypoxia-associated gene signatures exhibited reduced infiltration for these immune cells. By multivariate Cox regression, immune-related prognostic factors were identified. Patient clusters defined by high infiltration of DCs and T lymphocytes combined with HPV positivity or low hypoxia showed significantly prolonged survival. Thereby, cDC1 and CD8+ T cells emerged as independent prognostic factors for local and distant recurrence. These results might contribute to the implementation of an immune cell infiltration score predicting HNSCC patients' survival and such patient stratification might improve the design of future individualized radiochemo-(immuno)therapies.

IDO1 correlates with the immune landscape of head and neck squamous cell carcinoma: a study based on bioinformatics analyses

Background

Head and neck squamous cell carcinoma (HNSCCs) is a common cancer type with a high mortality rate and poor prognosis. Recent studies have focused on the role of immune checkpoints in HNSCC progression and in their potential use as prognostic markers and immunotherapeutic candidates. Some immune checkpoints, such as PD-1 and PD-L1, have been studied thoroughly in HNSCC. Other molecules, such as indoleamine 2,3-dioxygenase 1 (IDO1), have been investigated minimally.

Methods

IDO1 expression, prognostic potential, and association with the immune profile of HNSCC were explored using online databases, including GEPIA, UALCAN, TIMER2.0, cBioPortal, and LinkedOmics, which utilize TCGA datasets and are freely available for use. For validation purposes, seven pairs of primary and metastatic HNSCC were immunostained for IDO1.

Results

Our analysis revealed significantly higher expression of IDO1 in HNSCC, especially in HPV+ SCCs compared with healthy control tissue. However, IDO1 expression showed weak to no prognostic potential for overall and disease-free survival in HNSCC. IDO1 expression in HNSCC was positively correlated with several immune-related molecules, including most of the immune checkpoints. Additionally, GO enrichment analysis revealed that several immune-related pathways are positively correlated with IDO1 expression in HNSCC, such as response to type I interferon and lymphocyte-mediated immunity pathways. Finally, IDO1 expression positively correlated with infiltration of most of the immune cells in HNSCC, such as CD4+ T cells, CD8+ T cells, M1 and M2 macrophages, dendritic cells, and B cells.

Conclusion

IDO1 expression is closely correlated with the immune profile of the HNSCC. This observation should be explored further to elucidate the potential of targeting IDO1 as a novel immunotherapeutic approach for HNSCC.

Assessing the Knowledge of HPV-Associated Oropharyngeal Squamous Cell Carcinoma, HPV Vaccination, and Practice Scope among Saudi Dental Students in the Western Region

(1) Background: Human papillomavirus (HPV) infection is significantly associated with oropharyngeal squamous cell carcinoma (HPV-OPSCC), which is one of the fastest-growing cancer incidences globally. Dental practitioners play a crucial role in the primary and secondary prevention of HPV-OPSCC. There is little known about dental students' awareness regarding HPV-OPSCC and HPV vaccination, as well as their intention to promote 'primordial prevention' among their patients. HPV vaccine, and the extent of their professional responsibilities. (2) Methods: This cross-sectional study was conducted in the western region of Saudi Arabia and involved undergraduate dental students (n = 688) from six public and private dental schools. Participants were requested to complete a sequential-section anonymous online survey, with 257 successfully completing all sections of the questionnaire. The association between participant characteristics and HPV-OPSCC, HPV vaccination awareness ratings, and perceived engagement in prevention were analyzed using ANOVA and chi-squared testing. A binary logistic regression analysis was conducted to examine the variables linked to these outcomes. (3) Results: Generally, the overall level of awareness of HPV-OPSCC and HPV vaccination was acceptable, with an average score of 53.44 ± 29.3 out of 100. However, a significant knowledge gap was observed, with 53% of respondents being unaware of the common sites for HPV-OPSCC and 63.8% being uninformed of the appropriate age for HPV vaccination. Females and those with a prior history of sexually transmitted diseases (STDs) had considerably higher levels of HPV vaccination knowledge (p < 0.05). The participants showed a favorable attitude towards their responsibility of informing patients about HPV-OPSCC and advocating HPV immunization. (4) Conclusions: This study underscores the need to enhance dental students' understanding of HPV-OPSCC and HPV immunization, enabling them to effectively engage in primary and secondary preventative efforts against HPV-OPSCC.

Tumor Antigens beyond the Human Exome

With the advent of immunotherapeutics, a new era in the combat against cancer has begun. Particularly promising are neo-epitope-targeted therapies as the expression of neo-antigens is tumor-specific. In turn, this allows the selective targeting and killing of cancer cells whilst healthy cells remain largely unaffected. So far, many advances have been made in the development of treatment options which are tailored to the individual neo-epitope repertoire. The next big step is the achievement of efficacious "off-the-shelf" immunotherapies. For this, shared neo-epitopes propose an optimal target. Given the tremendous potential, a thorough understanding of the underlying mechanisms which lead to the formation of neo-antigens is of fundamental importance. Here, we review the various processes which result in the formation of neo-epitopes. Broadly, the origin of neo-epitopes can be categorized into three groups: canonical, noncanonical, and viral neo-epitopes. For the canonical neo-antigens that arise in direct consequence of somatic mutations, we summarize past and recent findings. Beyond that, our main focus is put on the discussion of noncanonical and viral neo-epitopes as we believe that targeting those provides an encouraging perspective to shape the future of cancer immunotherapeutics.

Tissue contexture determines the pattern and density of tumor-infiltrating immune cells in HPV-associated squamous cell carcinomas of oropharynx and uterine cervix

The profile of the antitumor immune response is an important factor determining patient clinical outcome. However, the influence of the tissue contexture on the composition of the tumor microenvironments of virally induced tumors is not clearly understood. Therefore, we analyzed the immune landscape of two HPV-associated malignancies: oropharyngeal squamous cell carcinoma (OPSCC) and squamous cell carcinoma of uterine cervix (CESC). We employed multiplex immunohistochemistry and immunofluorescence to evaluate the density and spatial distribution of immune cells in retrospective cohorts of OPSCC and CESC patients. This approach was complemented by transcriptomic analysis of purified primary tumor cells and in silico analysis of publicly available RNA sequencing data. Transcriptomic analysis showed similar immune profiles in OPSCC and CESC samples. Interestingly, immunostaining of OPSCC tissues revealed high densities of immune cells in both tumor stroma and tumor epithelium, whereas CESC samples were mainly characterized by the lack of immune cells in the tumor epithelium. However, in contrast to other immune cell populations, polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) were abundant in both segments of CESC samples and CESC-derived tumor cells expressed markedly higher levels of the PMN-MDSC chemoattractants CXCL1, CXCL5, and CXCL6 than OPSCC tumor cells. Taken together, despite their having the same etiologic agent, the immune infiltration pattern significantly differs between OPSCC and CESC, with a noticeable shift toward prominent MDSC infiltration in the latter. Our data thus present a rationale for a diverse approach to targeted therapy in patients with HPV-associated tumors of different tissue origins.

Constructing heterogeneous single-cell landscape and identifying microenvironment molecular characteristics of primary and lymphatic metastatic head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) accounts for more than half of head and neck tumors, roughly 90%. This study focused on constructing the heterogeneous landscape using single-cell and bulk transcriptomic data to identify molecular characteristics of the microenvironment in primary and lymphatic metastatic head and neck squamous carcinomas.

METHOD

The study enrolled 23 HNSCC samples with scRNA-seq data and 546 HNSCC samples from TCGA. We used Monocle to sort the cells and used CellPhoneDB to explore the cell-cell interactions. Infercnv, which was used to infer cells with apparent copy number variation based on single-cell sequencing transcriptome data. We re-evaluated HNSCC bulk RNA transcriptome data to characterize the functions of different cell types in shaping the immune microenvironment of HNSCC.

RESULTS

We combined genealogical reconstruction, CNV inference, and cellular interactions to uncover the characteristics of distinct cell populations in different disease states, differences in cancer and immune cell lineages of differentiation trajectories, and interactions between non-immune and immune cell. PD-1 and PD-L1/PD-L2 expressed extremely rare in T cells, the immune checkpoint molecule KLRB1-CLEC2D achieved a high-level expression. We identified three microenvironment-based HNSCC subtypes associated with the prognosis of HNSCC patients.

CONCLUSIONS

In summary, the present study dissected the intratumoral heterogeneity and immune microenvironment of primary and metastatic HNSCC, which is crucial to reveal the mechanisms of resistance to immunotherapy in HNSCC in different disease states and is expected to assist in the further investigation of the mechanism of HNSCC cell metastasis and guide the treatment of clinical patients.