Cancer Stem Cells in Head and Neck Squamous Cell Carcinoma.

Cancer stem cells (CSCs) are a small sub-population of cells within a tumor mass proficient of tumor initiation and progression. Distinguishing features possessed by CSCs encompass self-renewal, regeneration and capacity to differentiate. These cells are attributed to the phenomenon of aggression, recurrence and metastasis in neoplasms. Due to their cancer initiating and contributing features, a proper understanding of these CSCs and its microenvironment would aid in better understanding of cancer and designing better targeted therapeutic strategies for improved clinical outcome, thus improving the prognosis. This article dispenses a narrative review of CSCs in the context of head and neck carcinoma under the sub headings of overview of cancer stem cells, methods of isolation of these cells, putative CSC markers of head and neck cancer, signaling pathways used by these cells and their therapeutic implications.

Chondroid choristoma of the tongue: A rare case report.

Choristomas are tumor-like masses consisting of normal cells in an abnormal location. Choristomas of the oral cavity are rare lesions. We report a case of Cartilaginous choristoma on the ventral aspect of the tongue in a 25-year-old female. Clinical features, differential diagnosis, and tumoral origin theories are also discussed along with a meta-analysis of the reported cases in the PubMed database.

Comparative evaluation of immunohistochemical expression of MCM2 and Ki67 in oral epithelial dysplasia and oral squamous cell carcinoma.

Aim and Objectives: The aim and objective of the study were to evaluate the immunohistochemical expression of proliferative markers, Ki67, and MCM2 in oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC), to compare the relationship of their staining patterns, and to look for correlation between them, if any. Materials and Methods: Thirty archival paraffin-embedded tissue blocks of previously diagnosed cases of OED, OSCC each, and 10 normal oral mucosa were used in the study. Immunohistochemical staining for MCM2 and Ki67 markers was done and the slides were individually evaluated for MCM2 and Ki67 expression, with immunopositivity determined on the basis of dark brown staining of the nucleus. The number of positively stained nuclei was counted in 10 representative areas and the data were charted and statistically analyzed. Results: The overall mean expression of both the proteins increased progressively from normal mucosa to OED to OSCC. In normal mucosa, all positively stained nuclei were seen in the basal compartment of the epithelium, while in dysplastic cases, expression was seen toward the surface of squamous epithelium. In OSCC, the frequency of expression of MCM2 and Ki-67 proteins showed an inverse correlation with the degree of tumor differentiation. In well-differentiated cases, the positivity of either marker was restricted to the outermost layer of the tumor cells. In moderately differentiated cases, an expression of Ki-67 was more diffuse in inner layers, whereas the MCM2 antigen was found to be more intense and diffuse in both the inner and outer layers. Whereas in poorly differentiated SCC, positive expression was seen in most of the tumor cells, the mean expression of MCM2 was found to be higher than that of Ki67 in all cases. Conclusion: MCM2, as a proliferation marker, is superior to Ki67 as it indicates the capacity of proliferation and the ability of DNA replication of a cell.

Insight into the molecular pathogenesis of odontogenic lesions.

BACKGROUND: Odontogenic tumors, derived from epithelial, ectomesenchymal, and/or mesenchymal elements of the tooth-forming apparatus, constitute a heterogeneous group of lesions, including hamartomas, benign and malignant neoplasms with metastatic capabilities. HIGHLIGHT: This review provides a comprehensive overviewof the pathogenesis of odontogenic tumors and explains the associated molecular events in the context of hallmarks of cancer established by Hanahan D and Weinberg RA. Diagrammatic representations depicted in the article would facilitate easier understanding. CONCLUSION: A better understanding of the pathogenesis of the lesions may assist in determining patient's prognosis and devising better targeted therapeutic treatment, thus, reducing the morbidity and mortalityof patients.

Assessment of knowledge of oral pathologists and postgraduate students on safe laboratory practices during the COVID-19 pandemic.

BACKGROUND: Oral pathologists are involved in laboratory diagnosis and receive specimens of biopsy, oral cytologic smears and samples for hematology, biochemistry and microbiology and thus are at a risk for laboratory-acquired infections, which may occur inadvertently and can be considered as an occupational hazard. AIM AND OBJECTIVES: This study was conducted during the coronavirus disease (COVID-19) pandemic to assess the knowledge of oral pathologists and oral pathology postgraduate students regarding the safe laboratory practices, procedures and guidelines. MATERIALS AND METHODS: The study was a cross-sectional online questionnaire-based study. Questions were framed to evaluate the knowledge on specimen/sample collection, its handling, disposal and protective measures for laboratory personnel. The study population comprised oral pathologists and oral pathology postgraduate students of various dental colleges in India. A Google Doc format was used to create an effective computerized questionnaire system, and the link was forwarded to around 500 participants. The survey was fielded online between August 29, 2020, and September 5, 2020. Three hundred and twelve responses were received, which were downloaded as spreadsheets for subsequent data analysis. RESULTS: Mean value of right answers for the oral pathologists was 8.11 ± 2.02 and for postgraduate students was 7.38 ± 1.75. When the knowledge score between the two groups was compared, a statistically significant difference was found. CONCLUSION: This article compares and highlights the knowledge lacunae among the oral pathologists and oral pathologists postgraduate students in relation to guidelines to be followed for safety in the laboratory. Adhering to these biosafety regulations reduces occupational health hazards and enhances a safe working environment in the laboratory.

Collagen fibers in oral submucous fibrosis - A polarizing microscopy study using two special stains.

BACKGROUND: Oral submucous fibrosis (OSMF), a well-recognized oral potentially malignant disorder, results due to increased collagen production and reduced collagen degradation. AIMS AND OBJECTIVES: To qualitatively compare the staining properties of collagen in OSMF using two special stains based on their birefringent property using polarizing microscopy. The study also assessed the distribution and orientation of collagen fibers in different grades of OSMF. MATERIALS AND METHODS: A total of 73 subjects with different clinical and histopathological staging of OSMF comprised the study population. Histopathological examination was done using hematoxylin and eosin stain, Van Gieson and picrosirius red. Collagen fibers were analyzed for polarization colors, distribution, and orientation. RESULTS: Picrosirius red stained both thick and thin collagen fibers. Irrespective of the histopathological grades reddish orange and yellowish orange were the most predominant colors. Parallel arrangement of fibers was observed when stained with Van Gieson but picrosirius red stained sections showed a majority of parallel type I fibers with perpendicular type III fibers which increased with advancement in the histopathological grade. Yellowish orange and greenish yellow fibers were predominant in the lamina propria, while reddish orange fibers were predominant in the submucosa. CONCLUSION: Picrosirius red was found to be a better stain. Histopathological grading and polarization colors showed no association with each other. Collagen fibers were more thickly and tightly packed in the submucosa indicating that the process of fibrosis began there. The increase in perpendicular type III fibers with advancing histopathological grades suggested their role in fibrosis.

Comparative Study of Micronuclei Count in Patients with Different Tobacco-related Habits using Exfoliated Buccal Epithelial Cells: A Tool for Assessment of Genotoxicity.

AIM: To study and compare the genotoxic effects of tobacco using micronuclei count in individuals with different tobacco-related habits. MATERIALS AND METHODS: A cross-sectional study was done comprising 200 individuals, divided into four groups. Group I: 50 subjects with history of tobacco chewing, group II: 50 subjects with a history of smoking tobacco, group III: 50 subjects with a history of both tobacco chewing and smoking, and group IV: 50 subjects without any habits as controls (age-matched). The study groups were individually further divided into three subgroups which comprised of subjects with history of substance abuse for less than 5, 5 to 10, and greater than 10 years. Exfoliated cells from the buccal mucosa of the subjects were collected and stained using Giemsa stain. A total of 1,000 cells were examined for each case and micronuclei frequency was scored according to the guidelines given by Tolbert et al. Results: The mean number of micronuclei count was 18.28 ± 10.0 in group I (smokeless tobacco users), 11.38 ± 6.3 in group II (subjects with history of tobacco smoking), 22.44 ± 9.8 in group III (subjects with history of using both smokeless and smokable form of tobacco), and 4.86 ± 2.4 in the control group. The statistical difference was found to be highly significant (p < 0.001). Similarly, based on the duration, highly significant difference was notable in the mean number of micronuclei in subjects who had a history of substance abuse for more than 10 years. CONCLUSION: A significantly higher micronucleus frequency was found in smokeless tobacco users than in smokers and controls. Micronuclei assay in the exfoliated buccal cells is a useful and minimally invasive method for monitoring early genotoxic damage. CLINICAL SIGNIFICANCE: Micronuclei assay can be used to detect genotoxic damage at the earliest and, if intervened at this point, may prevent frank malignancy, morbidity, and mortality.

Clinicopathological Profile and Malignant Transformation in Oral Lichen Planus: A Retrospective Study.

OBJECTIVES: The aim of this study was to analyze the histopathologically diagnosed cases of oral lichen planus (OLP) in terms of age, gender, clinical variant, site, hyperpigmentation, systemic illness, grade of dysplasia, and associated malignant transformation. This study also intended to do a review of reported cases of OLP with malignant transformation. MATERIALS AND METHODS: One hundred and forty-three cases of histopathologically diagnosed OLP between 2010 and 2016 were retrospectively reviewed. Demographic and clinicopathological data including malignant transformation were obtained. The data obtained were analyzed using the Statistical Package for the Social Sciences (SPSS) software for Windows version 20.0 (IBM SPSS, SPSS Inc., Chicago, IL, USA). A review of published literature on OLP with malignant transformation was also done from 1988 to 2017 and tabulated. RESULTS: OLP in this study showed a male predilection with most of the patients in the third decade. The buccal mucosa (bilateral presentation) was the most common site (79.72%), and reticular type was the most common clinical type (79.02%) followed by erosive type (20.98%). The majority (92.31%) of cases were diagnosed with OLP without dysplasia. The rest (7.69%) of dysplastic cases were predominantly seen in the buccal mucosa of 58 years and above, female patients manifesting mainly as erosive type. Two patients (1.4%) previously diagnosed clinically and histopathologically as OLP developed oral squamous cell carcinoma. CONCLUSION: The present investigation revealed the predominance of OLP among middle-aged male population and the prevalence of bilateral involvement of buccal mucosa. Two of our cases showed malignant transformation over an average period of 3.5 years. The outcome of this study emphasizes the role of clinical follow-up of patients with OLP.

Human Papilloma Virus (HPV) Induced Head & Neck Squamous Cell Carcinoma: A Comprehensive Retrospect.

Head and Neck Squamous Cell Carcinoma accounts for the sixth most common malignancy occurring worldwide with tobacco and alcohol being the two well established risk factors. In the recent years, substantial evidence has been obtained that Human Papilloma Virus (HPV) associated head and neck cancers are on the rise. This article provides an insight into the structure of HPV genome, molecular pathogenesis, detection methods and clinical implications of HPV positive Head and Neck Squamous Cell Carcinoma.