Immunohistochemical staining of Langerhans cells in HPV-positive and HPV-negative cases of oral squamous cells carcinoma

The role of the epithelial sentinels, Langerhans cells and γδT cells, in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) arises in the oral epithelium, a tissue in which immune surveillance is mediated by its primary resident leukocytes, Langerhans cells (LCs), and γδT cells. Under steady-state conditions, LCs and γδT cells play a critical role in maintaining oral mucosal homeostasis. As antigen-presenting cells of stratified epithelia, LCs respond to various challenges faced by the epithelium, orchestrating innate, and adaptive immune responses in order to resolve them. γδT cells also sense diverse epithelial insults and react rapidly through cytokine production and cytolytic activity. These epithelial sentinels are also considered to be the first leukocytes in the oral epithelium to encounter early carcinogenic events that have the potential of becoming OSCC. As evident in many malignancies, leukocyte populations help prevent cancer development although they also promote tumor progression. OSCC is no exception, as studies have reported both anti- and pro-tumor roles of LCs and γδT cells. In this review, we summarize the ontogeny of LCs and γδT cells in the oral epithelium and discuss their role in OSCC.

The Immune Microenvironment in Head and Neck Squamous Cell Carcinoma: on Subsets and Subsites

PURPOSE

To understand why some patients respond to immunotherapy but many do not, a clear picture of the tumor microenvironment (TME) of head and neck squamous cell carcinoma (HNSCC) is key. Here we review the current understanding on the immune composition per HNSCC subsite, the importance of the tumor's etiology and the prognostic power of specific immune cells.

RECENT FINDINGS

Large cohort data are mostly based on deconvolution of transcriptional databases. Studies focusing on infiltrate localization often entail small cohorts, a mixture of HNSCC subsites, or focus on a single immune marker rather than the interaction between cells within the TME. Conclusions on the prognostic impact of specific immune cells in HNSCC are hampered by the use of heterogeneous or small cohorts. To move forward, the field should focus on deciphering the immune composition per HNSCC subsite, in powered cohorts and considering the molecular diversity in this disease.

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.

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.

Immunohistochemical characterization of epidermal dendritic-like cells in giant mudskipper, Periophthalmodon schlosseri

Giant Mudskipper, Periophthalmodon schlosseri (Pallas, 1770), is euryhaline, amphibious, and air-breathing fish. These fishes live in close association to mangrove forests and often spend over 90% of time out of water, in adjacent mudflats. They have developed morphological and physiological adaptations to satisfy their unique lifestyles. The skin is the primary interface between the body and the environment, and has a central role in host defence. The initiation of immune responses to antigens in the vertebrate skin has often been attributed to epidermal Langerhans'cells (LC) that are dendritic cells (DC), antigen-presenting cells (APC) which reside in the epidermis. Dendritic cells have been characterized morphologically and functionally in the teleost fish tissues such as rainbow trout, salmonids, medaka, African catfish and zebrafish. However, there is no evidence of the presence of DCs and their role in mudskippers immunity. The aim of this preliminary study was to characterize, through use of specific antibodies: Toll-like receptor 2, S100, serotonin (5-HT), and Vesicular acetylcholine transporter VAChT, a specific DC-like subpopulation in Pn. schlosseri's epidermis.

Prevalence of oral and oropharyngeal human papillomavirus infection in Brazilian population studies: a systematic review

Introduction

Human papillomavirus has been associated with head and neck squamous cell carcinoma. However, there is no conclusive evidence on the prevalence of oral or pharyngeal infection by human papillomavirus in the Brazilian population.

Objective

To determine the rate of human papillomavirus infection in the Brazilian population.

Methods

Systematic review of published articles. Medline, The Cochrane Library, Embase, Lilacs (Latin American and Caribbean Health Sciences) and Scielo electronic databases were searched. The search included published articles up to December 2014 in Portuguese, Spanish and English. A wide search strategy was employed in order to avoid publication biases and to assess studies dealing only with oral and/or oropharyngeal human papillomavirus infections in the Brazilian population.

Results

The 42 selected articles enrolled 4066 patients. It was observed that oral or oropharyngeal human papillomavirus infections were identified in 738 patients (18.2%; IC 95 17.6–18.8), varying between 0.0% and 91.9%. The prevalences of oral or oropharyngeal human papillomavirus infections were respectively 6.2%, 44.6%, 44.4%, 27.4%, 38.5% and 11.9% for healthy people, those with benign oral lesions, pre-malignant lesions, oral or oropharyngeal squamous cell carcinoma, risk groups (patients with genital human papillomavirus lesions or infected partners) and immunocompromised patients. The risk of human papillomavirus infection was estimated for each subgroup and it was evident that, when compared to the healthy population, the risk of human papillomavirus infection was approximately 1.5–9.0 times higher, especially in patients with an immunodeficiency, oral lesions and squamous cell carcinoma. The rates of the most well-known oncogenic types (human papillomavirus 16 and/or 18) also show this increased risk.

Conclusions

Globally, the Brazilian healthy population has a very low oral human papillomavirus infection rate. Other groups, such as at-risk patients or their partners, immunocompromised patients, people with oral lesions and patients with oral cavity or oropharyngeal squamous cell carcinoma have a high risk of human papillomavirus infection.

A Comparative Immunohistochemical Analysis of Langerhans Cells in Oral Mucosa, Oral Lichen Planus and Oral Squamous Cell Carcinoma

BACKGROUND

Langerhans cells (LCs) are immunocompetent cells resident within oral mucosa which, together with intraepithelial lymphocytes, play a role in mucosal defence. LCs play a role in the pathogenesis of Oral lichen planus (OLP), a chronic mucocutaneous disorder thought to result from cell-mediated immune damage. In oral squamous cell carcinoma (OSCC), LCs are thought to present tumour antigens to the lymphocytes.

AIM

To assess and compare LCs immuno-histochemically in normal mucosa, oral lichen planus and oral squamous cell carcinoma using anti S100 antibody and to know whether LCs play any role in local immune response to these diseases.

MATERIALS AND METHODS

The study was carried out in 65 cases (study group), 30 oral lichen planus and 35 oral squamous cell carcinoma (15 well differentiated, 14 moderately differentiated and 6 poorly differentiated), that were randomly selected from the archives of department of oral pathology and along with control group consisting of 30 normal healthy mucosa. The tissue sections were stained immunohisto-chemically by using anti S100 antibody in each group for detection of LCs.

RESULTS

There was significant change in mean value of number of LCs in the study groups i.e. OLP and OSCC when compared to that of control group. The results of our study also revealed that there was decrease in the mean value of langerhans cells as the tumour progressed from well differentiated squamous cell carcinoma to poorly differentiated LCs carcinoma.

CONCLUSION

A better understanding and clarity of LCs is pivotal for designing novel or improved therapeutic approaches that will allow proper functioning of LC's in patients with OLP and OSCC, thus significantly reducing the morbidity of OLP and OSCC patients.