Role of tissue eosinophils in oral Leukoplakia: A pilot study

Eosinophils in Oral Disease: A Narrative Review

The prevalence of diseases characterised by eosinophilia is on the rise, emphasising the importance of understanding the role of eosinophils in these conditions. Eosinophils are a subset of granulocytes that contribute to the body's defence against bacterial, viral, and parasitic infections, but they are also implicated in haemostatic processes, including immunoregulation and allergic reactions. They contain cytoplasmic granules which can be selectively mobilised and secrete specific proteins, including chemokines, cytokines, enzymes, extracellular matrix, and growth factors. There are multiple biological and emerging functions of these specialised immune cells, including cancer surveillance, tissue remodelling and development. Several oral diseases, including oral cancer, are associated with either tissue or blood eosinophilia; however, their exact mechanism of action in the pathogenesis of these diseases remains unclear. This review presents a comprehensive synopsis of the most recent literature for both clinicians and scientists in relation to eosinophils and oral diseases and reveals a significant knowledge gap in this area of research.

The Immune Cells in the Development of Oral Squamous Cell Carcinoma

A still unresolved issue surrounding tumor formation concerns the role that the immune system plays in preventing the formation and progression of neoplasia, including oral squamous cell carcinoma (OSCC). Antitumor immunity has historically been seen as a critical barrier for cancer cells to develop, grow and spread, and this can be modulated using immunotherapies to achieve antitumor clinical responses. However, it has recently become clear that tumor-associated immunity, particularly the inflammatory microenvironment, has the paradoxical effect of enhancing tumorigenesis and progression. In this review, we discuss the multifaceted function of infiltrating immune cells in suppressing or promoting premalignancy and cancer. In particular, we report on the evidence supporting a role for T lymphocytes, dendritic cells, macrophages, and neutrophils in the development and progression of oral potentially malignant disorders (OPMD) and OSCC. We also draw attention to the clinical relevance of immune cell phenotypes and associated molecules for use as biomarkers and to the translatability of current research findings to improve classification systems and precision medicine in patients with OSCC.

Precancerous Lesions of the Head and Neck Region and Their Stromal Aberrations: Piecemeal Data

Head and neck squamous cell carcinomas (HNSCCs) develop through a series of precancerous stages from a pool of potentially malignant disorders (PMDs). Although we understand the genetic changes that lead to HNSCC, our understanding of the role of the stroma in the progression from precancer to cancer is limited. The stroma is the primary battleground between the forces that prevent and promote cancer growth. Targeting the stroma has yielded promising cancer therapies. However, the stroma at the precancerous stage of HNSCCs is poorly defined, and we may miss opportunities for chemopreventive interventions. PMDs already exhibit many features of the HNSCC stroma, such as inflammation, neovascularization, and immune suppression. Still, they do not induce cancer-associated fibroblasts or destroy the basal lamina, the stroma's initial structure. Our review aims to summarize the current understanding of the transition from precancer to cancer stroma and how this knowledge can reveal opportunities and limitations for diagnostic, prognostic, and therapeutic decisions to benefit patients. We will discuss what may be needed to fulfill the promise of the precancerous stroma as a target to prevent progression to cancer.

Genetic Changes Driving Immunosuppressive Microenvironments in Oral Premalignancy

Oral premalignant lesions (OPLs) are the precursors to oral cavity cancers, and have variable rates of progression to invasive disease. As an intermediate state, OPLs have acquired a subset of the genomic alterations while arising in an oral inflammatory environment. These specific genomic changes may facilitate the transition to an immune microenvironment that permits malignant transformation. Here, we will discuss mechanisms by which OPLs develop an immunosuppressive microenvironment that facilitates progression to invasive cancer. We will describe how genomic alterations and immune microenvironmental changes co-evolve and cooperate to promote OSCC progression. Finally, we will describe how these immune microenvironmental changes provide specific and unique evolutionary vulnerabilities for targeted therapies. Therefore, understanding the genomic changes that drive immunosuppressive microenvironments may eventually translate into novel biomarker and/or therapeutic approaches to limit the progression of OPLs to potential lethal oral cancers.

Tumour-associated tissue eosinophilia (TATE) in oral squamous cell carcinoma: a comprehensive review

Oral squamous cell carcinoma is the most common head and neck malignancy, characterised by high invasive capacity, lymph node metastasis, and high recurrence rate. Among the morphological features of oral cancer, the tumour-associated tissue eosinophilia has gained growing interest in the last years. Eosinophils are a minor subpopulation of leukocytes, representing 1-3% of all circulating white blood cells. The presence of high levels of eosinophils is associated with several diseases, but their role in cancer pathophysiology is controversial. In particular, an uncertain and contradictory relationship exists between the exact role of tumour-associated tissue eosinophilia and oral cancer development. Many studies have shown that tumour-associated tissue eosinophilia increases both in the progression of oral potentially malignant disorders as well as in the grade and stage progression of oral cancer. Despite this, both negative and positive prognostic outcomes have been associated with eosinophil infiltration. The heterogeneous results may be partially due both to several methodological inconsistencies and to an incorrect interpretation of the physiological role of eosinophils. Therefore, further studies to elucidate the contribution of eosinophil infiltration are needed, focusing on the existence of eosinophil subpopulations regulated by the cancer immune microenvironment. Furthermore, the correct reporting of prognostic marker research is encouraged, in order to ensure the reproducibility and the comparability of the results from different studies.

Involvement of the anti-inflammatory, anti-apoptotic, and anti-secretory activity of bee venom in its therapeutic effects on acetylsalicylic acid-induced gastric ulceration in rats

Acetylsalicylic acid (ASA) is the most highly consumed pharmaceutical product worldwide. Importantly, gastrointestinal ulceration due to ASA is a major complication. Hence, the present work aimed to examine, for the first time, the healing properties of bee venom (BV) in acute gastric ulceration induced by ASA. Forty adult male Sprague-Dawley rats were divided into four groups that received distilled water only, ASA (500 mg/kg BW) twice daily for 3 days, ASA for 3 days followed by BV (2 mg/kg BW) for 7 days, or ASA for 3 days followed by ranitidine hydrochloride (50 mg/kg BW) for 7 days. Haematological analysis, haemostatic evaluation, and inflammatory marker estimation were performed. Rat stomachs were collected for ulcer scoring, gene expression analysis, oxidative stress assays, histopathological and immunohistochemical examinations, and tissue eosinophil scoring. The results revealed that BV markedly decreased the ulcer index, pro-inflammatory cytokine levels, malondialdehyde levels, BAX distribution, caspase-3 expression, and tissue eosinophil levels. Additionally, significant increases in antioxidant enzymes and heat shock protein 70 localization in gastric tissue were evident following BV treatment after ASA exposure. Also, BV has been found to attenuate the haematological, haemostatic, and histopathological alterations induced by ASA. Our findings collectively indicate that the gastroprotective effect of BV against ASA-induced ulceration in rats is mediated by its antioxidant, anti-inflammatory, anti-apoptotic, and anti-secretory properties.

Tissue eosinophilia in oral intraepithelial neoplasia as a probable indicator of invasion

OBJECTIVE

To investigate the presence of eosinophils in oral intraepithelial neoplasia (OIN) and oral squamous cell carcinoma (OSCC) lesions and its relation to invasion.

SUBJECTS AND METHODS

Ninety-nine oral biopsies were selected and subdivided into the following: OIN-1(16 cases), OIN-2 (18 cases), OIN-3 (17 cases), microinvasive OSCC (10 cases), non-metastatic OSCC (22 cases) and metastatic OSCC (16 cases). The tissue eosinophilia was evaluated histologically in slices stained with haematoxylin and eosin.

RESULTS

Eosinophil distribution was associated with diagnosis severity (p < .01). A significant difference was found between OIN-3 or microinvasive OSCC and non-metastatic or metastatic OSCC. Stromal invasion threshold was 7 eos/10 high power field (hpf) (96.1% specificity and 62.5% sensitivity). Eosinophils were absent in OIN-1; in OIN-2, two cases were positive. In OIN-3, five cases showed tissue eosinophilia, four of which had ≥3 eos/hpf or ≥7 eos/10 hpf. Three cases were suspected of invasion; two had a previous history of OSCC with elevated eosinophil infiltrate. In microinvasive OSCC, the four positive cases presented ≥3 eos/hpf and ≥7 eos/10 hpf. Although not significantly different, non-metastatic invasive OSCC had a higher number of cases (68.2%) with ≥22 eos/10 hpf contrasting with 50% in metastatic OSCC.

CONCLUSION

Our results suggest that eosinophils can be considered an indicator of invasion in OIN, helping in cases of difficult diagnosis.

Expression of Galectins-1 and Galectin-3 in Stomach and Colorectal Cancer with Tissue Eosinophilia

We analyzed the expression of galectin-1 and galectin-3 in tumor tissue in stomach and colorectal cancer with and without tissue eosinophilia. Low expression of galectin-3 was detected in all patients with malignant gastrointestinal tumors irrespective of the presence of eosinophilia. Low expression of galectin-1 was detected only in patients with gastrointestinal cancer associated with eosinophilia. Association of galectin-1 expression with eosinophilic infiltration of the tumor tissue in stomach and colorectal cancer was detected.