Evaluation of Cytotoxic T Lymphocytes and Natural Killer Cell Distribution in Oral Squamous Cell Carcinoma and Oral Epithelial Dysplasia: An Immunohistochemical Study

Background The tumor microenvironment comprises stromal cells, a few immune cells, vascular channels, and an extracellular matrix. The immune cells play a pivotal role in arresting the development of various tumors by identifying and killing the abnormal tumor cells. These immune cells with cytotoxic function include the natural killer (NK) cells and CD8+ T lymphocytes. Human NK cells express the cell surface marker CD57 and can be identified by using monoclonal antibodies. CD8+ cytotoxic T cells are a critical subpopulation of T cells and are important mediators of adaptive immunity. The anti-tumor immunity is important to assess the prognosis of tumors and develop new therapies. This study aimed to evaluate the immunohistochemical expression of CD8 and CD57 immune cells in oral squamous cell carcinoma (OSCC), oral epithelial dysplasia (OED), and normal oral mucosa. Methodology Clinically diagnosed and histopathologically confirmed cases of OSCC (n = 22), oral leukoplakia with OED (n = 22), and normal oral mucosa (n = 22) comprised the study groups. The tissue sections were subjected to immunohistochemical analysis for CD8 and CD57 expression by calculation of the mean labeling index. The results were statistically analyzed using a one-way analysis of variance, Bonferroni multiple comparison test, and Student's t-test. SPSS software version 20.0 (IBM Corp., Armonk, NY, USA) was used for the statistical analysis, and the significance level was set at 0.05. Results An overall statistically significant difference was obtained in the number of CD8+ T lymphocyte cells and CD57+ NK cells when compared between OSCC, OED, and normal oral mucosa (p = 0.01). Variations in the number of CD8+ T lymphocyte cells and CD57+ NK cells were observed when a comparison was made between OED and OSCC and between OSCC and normal mucosal samples (p = 0.01). The study results showed that the mean labeling index of CD8 and CD57 increased in OSCC when compared to OED and normal mucosa (p = 0.01). Conclusions Samples of OED with moderate or severe dysplasia and samples of OSCC were accompanied by a higher level of infiltrating immune cells such as T cells, B cells, NK cells, and macrophages when compared to normal mucosa. The results suggested that the expression of CD8 and CD57 cells increased from normal mucosa to OED and the highest expression was found in OSCC. CD8 and CD57 could be used as surrogate markers to assess the malignant potential of the lesion and to determine the prognosis of patients with oral cancer.

Identification and Evaluation of Cancer Stem Cells in Oral Squamous Cell Carcinoma and Oral Epithelial Dysplasia Using NANOG: An Immunohistochemical Study

BACKGROUND

Squamous cell carcinoma of the oral cavity may show precursor lesions, termed as potentially malignant disorders, of which leukoplakia is the most frequent one. Oral leukoplakia is a clinical diagnosis for which the histological diagnosis may be either hyperplasia or oral epithelial dysplasia (OED) and sometimes even oral squamous cell carcinoma (OSCC). Cancer stem cells (CSCs), identified in various tumors, are a specific group of cells that exhibit the properties of self-renewal and differentiation. Among the various biomarkers that identify CSCs, the transcription factor NANOG is considered to be a significant one.

AIM

In this study, we intend to identify and compare the immunohistochemical expression of NANOG in OSCC, OED, and normal oral mucosa.

METHODOLOGY

Tissue blocks of OSCC (n=28), OED (n=28), and normal oral mucosa (n=28) were used in this study. Specimens were immunohistochemically analyzed for NANOG expression. The results were statistically analyzed using one-way ANOVA, Games-Howell post hoc, and Student t-test. Statistical Product and Service Solutions (SPSS, version 21; IBM SPSS Statistics for Windows, Armonk, NY) software was used for performing the statistical analysis, and the level of significance was set as 0.05.

OBSERVATIONS

NANOG expression was higher in OSCC when compared to oral dysplasias and normal oral mucosa, in decreasing order. A significantly higher histo-score and labeling index score were observed in OSCC and oral dysplasias compared to normal oral mucosa (p=<0.001).

CONCLUSION

The expression levels of NANOG were positively correlated with disease progression in OSCC, implicating that NANOG can be used as a surrogate marker of oral oncogenesis and prognosis. Therefore, decoding the molecular mechanisms of NANOG regulation in the progression of cancer helps in developing new therapeutic strategies for oral cancer.

Chondrosarcoma of the maxilla in a young female: A case report

ABSTRACT

Sarcomas of the head and neck region are rare tumors, constituting less than 1% of malignant neoplasms in this area. Approximately 20% of these sarcomas originate from bone or cartilage. Chondrosarcomas are malignant mesenchymal tumors showing cartilaginous differentiation. These tumors usually show a predilection to the male gender and occur commonly in the older age group. Here, we report a case of chondrosarcoma of the anterior maxilla in a young female.

Immunohistochemical expression of cyclooxygenase-2 in oral lichen planus and normal oral mucosa

BACKGROUND

Oral lichen planus (OLP) is a chronic inflammatory disease for which the pathogenesis is complex and not fully understood; autoimmunity has been suggested as a causative factor. World health organization (WHO) has classified OLP as a potentially malignant lesion. Cyclooxygenase-2 (COX-2) is an inducible key enzyme that generates prostanoids which play a critical role in inflammation, immunopathology; also considered as a malignant potential marker.

AIMS

The present study was conducted to analyze and compare epithelial COX-2 expression in OLP clinical subtypes and normal oral mucosa to evaluate its role in the pathophysiology of the disease process.

METHODS

This retrospective immunohistochemistry (IHC) study was performed on tissue sections of 30 OLP and 10 normal oral mucosae for COX-2 expression.

STATISTICAL ANALYSIS USED

Descriptive and comparative statistical methods were done using 'one-way Analysis of Variance (ANOVA), 't' and Chi-square tests.

RESULTS

All the OLP showed epithelial COX-2 expression; strong expression was noted in 80% of the OLP while normal oral mucosa sections showed no expression. Cox-2 expression was significantly higher in erosive lichen planus compared to reticular lichen planus.

CONCLUSIONS

Strong expression of COX-2 in OLP suggested its important role in pathogenesis. Although COX-2 has been connected to malignant development and autoimmunity, as the malignant development in OLP is quite rare, this study suggests that increased levels of COX-2 seen here may support an autoimmune cause of the disease process.

Evaluation of aryl hydrocarbon receptor expression in oral squamous cell carcinoma and normal oral mucosa using western blot

Background

Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that acts as a binding site for toxic chemicals, particularly the dioxin group of chemicals. Elevated levels of AHR have been observed in various human cancers, including lung carcinomas, hepatic carcinomas and in mammary tumors. However, the expression of AHR in oral squamous cell carcinoma (OSCC) patients who are tobacco users are less explored.

Aims and Objectives

The aim of the present study is to evaluate and compare AHR levels in OSSC patients and in normals using Western blot technique in an attempt to explore the possible role of AHR in oral carcinogenesis.

Materials and Methods

The study sample consisted of ten oral squamous cell carcinoma cases which were diagnosed clinically and confirmed histopathologically as OSCC and four samples of the normal oral mucosa. AHR protein expression was evaluated using Western blot technique and chemiluminescence detection kit. The densitometry was performed on a Microtek scan maker MSP flatbed scanner and quantified using Image J software. Mean AHR protein levels were calculated and compared between OSCC and normal oral mucosa using Student's t-test.

Results

The mean AHR protein level in OSCC samples (n = 10) was 2878.90 ± 1231.27 and 975.75 ± 227.27 in the normal oral mucosa (n = 4). The OSCC samples showed significantly higher levels of AHR protein compared to the normal oral mucosa (P = 0.008).

Conclusion

The study showed a significantly higher expression of AHR in oral squamous cell carcinoma samples when compared to the normal oral mucosa, suggesting a possible role of AHR in the initiation, promotion and progression of oral squamous cell carcinoma.

Epithelial-mesenchymal transition in oral squamous cell carcinoma: An insight into molecular mechanisms and clinical implications

Epithelial-mesenchymal transition (EMT) is an important event in embryonic development, fibrosis and cancer invasion. During cancer progression, the activation of EMT permits cancer cells to acquire migratory, invasive and stem-like properties. Despite recent advances in treatment, there is no improvement in the 5-year overall survival rate of oral squamous cell carcinoma (OSCC). Local recurrence and lymph node metastasis are considered to be mainly responsible for the low survival rate in OSCC. EMT plays a major role in local recurrence and lymph node metastasis of oral cancer. This review article addresses the clinical implications of EMT in OSCC and explains the molecular mechanisms of EMT, highlighting the cadherin switching and signaling pathways involved.

Cancer stem cells: A comprehensive review on identification and therapeutic implications

Cancer stem cells (CSCs) are distinct subpopulations of tumor cells that possess the ability for perpetual self-renewal and proliferation. They produce downstream progenitor cells and cancer cells that drive tumor growth. Studies of many cancer types including oral squamous cell carcinoma (OSCC) have identified CSCs using specific markers, but it is still unclear as to where in the stem cell hierarchy these markers fall. This is compounded further by the presence of multiple CSC subtypes within OSCC, making investigation reliant on the use of multiple markers. This review paper focuses on the current knowledge in CSC markers including OCT4, SOX2, NANOG, aldehyde dehydrogenase 1, CD44, CD24, CD133 and Musashi-1, highlighting their use and validity in OSCC CSC research.

Analysis of enamel rod end pattern for personal identification

Background

Microscopically, groups of enamel rods run in unique direction, which differ from adjacent group of enamel rods and results in forming different patterns of enamel rod endings on tooth surface. These are called as tooth prints and they help in personal identification in forensic odontology.

Aims and Objectives

The aim of the present study is to analyze the enamel rod end pattern on the tooth surface for personal identification and to analyze the familial inheritance of enamel rod end pattern.

Materials and Methods

In the present study, 100 different families were considered for the analysis of tooth print pattern. In each family, four members were present. The maxillary central incisor, canine and first premolar were selected. Enamel rod end pattern was recorded using acetate peel technique and analyzed using Verifinger^® standard SDK version 6.7 software.

Statistical Analysis

Data analysis was performed using the SPSS software. Contingency coefficient statistical analysis was used for the comparison of tooth print pattern in incisors, canines and premolars based on age and gender. P < 0.05 was considered statistically significant.

Results

The present study showed that a tooth print is composed of combination of eight distinct subpatterns, namely wavy branched, wavy unbranched, linear branched, linear unbranched, whorl open, whorl closed, loop and stem-like pattern. Wavy branched pattern was found to be the most predominant pattern in incisors, canines and first premolars in our study. Familial tendency of tooth print pattern in incisors, canines and premolars was noticed in 65%, 66% and 52% of the families, respectively.

Conclusion

Tooth prints are unique to an individual and can be used as a valuable inexpensive tool in forensic odontology for personal identification.

Classification of odontogenic cysts and tumors - Antecedents

Pierre Paul Broca produced a monograph on tumor classification which also included the classification of odontogenic tumors (OTs). The terminology used to describe malignant epithelial OTs has varied since the World Health Organization published the initial consensus on the taxonomy of OTs. Minor changes were introduced in the second edition. It is only in the very recent years that additional knowledge has accumulated and refined the classification. This review emphasizes on reasons for modification by each author and the recent acceptance.

Facts in artifacts

Examination of microscopic sections of animal tissues reveals facts which are not always related to its normal histology or pathology. Processing of tissue specimens consists of lengthy procedures from the stage of surgical removal to the stained and mounted microscopic sections. Defects are common in tissue sections as a result of faulty procedures. These defects are referred to as artifacts. They lead to misinterpretation of histopathological diagnosis but at times they throw limelight into diagnosis. This paper attempts to put together all the facts regarding the various artifacts that are encountered in histopathology.

Prion diseases in humans: oral and dental implications

Prion diseases are a group of neurodegenerative disorders characterized by accumulation of abnormal prion proteins in the central nervous system. The prions resist conventional sterilization procedures especially when infected tissue becomes dried onto metal or glass surfaces. This article, a review of literature collected using Pubmed as search engine, describes the oral manifestations of prion diseases in addition to studying the possibility of cross contamination in the dental office. The article emphasizes the importance for dentists to be aware of these diseases, to identify the high-risk patients by obtaining adequate medical history and to know the appropriate deactivation procedures to be followed.

Oral lichen planus: An update on pathogenesis and treatment

Oral lichen planus (OLP) is a chronic inflammatory disease that affects the mucus membrane of the oral cavity. It is a T-cell mediated autoimmune disease in which the cytotoxic CD8+ T cells trigger apoptosis of the basal cells of the oral epithelium. Several antigen-specific and nonspecific inflammatory mechanisms have been put forward to explain the accumulation and homing of CD8+ T cells subepithelially and the subsequent keratinocyte apoptosis. A wide spectrum of treatment modalities is available, from topical corticosteroids to laser ablation of the lesion. In this review, we discuss the various concepts in the pathogenesis and current treatment modalities of OLP.

Rapidly enlarging mass following dental extraction

Oral melanoma (OM) is a rare, malignant neoplasm of melanocytic origin. It accounts for 0.2 - 8% of all melanomas. In contrast to its cutaneous counterpart, OM has poor prognosis, possibly due to late clinical diagnosis, nonexistence of standardized clinical or histopathological grading and anatomical limitation in complete excision of the lesion. For better understanding of the lesion, case reports are still considered to be the source of information. Here we present a case of oral primary melanoma occurring in an uncommon site, the mandibular gingiva, with review of related literature.

Ageing and its implications

Ageing processes are defined as those that increase the susceptibility of individuals, as they grow older, to the factors that eventually lead to death. It is a complex multi-factorial process, where several factors may interact simultaneously and may operate at many levels of functional organization. The heterogeneity of ageing phenotype among individuals of the same species and differences in longevity among species are due to the contribution of both genetic and environmental factors in shaping the life span. The various theories of ageing and their proposed roles are discussed in this review.