Effects of heated tobacco products on gingival epithelial cells

Objective and Background: Heated tobacco products have recently become commercially available. These products, as well as combustible cigarettes, produce aerosols; the risk of various diseases associated with heated tobacco products may be the same as or higher than that with combustible cigarettes. In this study, we examined the effect of Ploom TECH+ extract on gingival epithelial cells. Methods: Tobacco leaves from Ploom TECH+ tobacco capsules and water were mixed and heated; the supernatant subsequently collected was the heated tobacco product (HTP; control: HTP not added). Normal human gingival epithelial progenitors were cultured alternately with or without HTP for a total of 1 month. Subsequently, RNA, DNA, and proteins were isolated from these samples and comprehensively analyzed using RNA sequencing (RNA-seq), reduced representation bisulfite sequencing (RRBS), and western blotting, respectively. Results: RNA-seq revealed that 284 genes showed a two-fold increase and 145 genes showed a two-fold decrease in gene expression. A heat map showed genetic differences between the control and HTP groups. A principal component analysis plot showed a clear genetic distribution between the control and HTP. Gene Ontology (GO) analysis showed that genes related to seven GO terms, including cornification and keratinization, were induced by long-term HTP stimulation. By contrast, GO pathways with a significant decrease in component expression were not detected. RRBS revealed that CpG island methylation increased more than two-fold in 158 genes and decreased to less than two-fold in 171 genes. Methylation of these CpG islands was not correlated with changes in gene expression levels. HTP treatment increased S100A7 expression. Conclusion: Long-term HTP stimulation affected epithelial differentiation and keratinization of gingival epithelial cells. Thus, habitual use of Ploom TECH+ may be a risk factor for tobacco-related oral mucosal diseases

Myoepithelioma of the Palate: A Case Report

<p><span class="fontstyle0">Myoepithelioma, a benign tumor, occurs with a frequency of 1.5% among all salivary gland tumors, and it most commonly affects the parotid gland. Nearly the entire epithelium is composed of neoplastic myoepithelial cells exhibiting spindle, plasmacytic, epithelial-like, and clear cells. </span><span class="fontstyle2"><strong>Case Report</strong>: </span><span class="fontstyle0">A 52-year-old woman with myoepithelioma of the palate. The patient was referred to our hospital with a chief complaint of swelling on the right side of the palate. Following clinical and intraoral examinations, the tumor was removed under general anesthesia. Viewed microscopically, the tumor was seen to be surrounded by a fbrous membrane, primarily composed of a solid growth of neoplastic myoepithelial cells, virtually surrounding a hyaline-like eosinophilic substance. Immunohistochemical examination revealed strongly-positive reactions by the tumor cells for widespectrum cytokeratin (CK wide), vimentin, and S-100 proteins. CK 7, smooth muscle actin (SMA), p63, and glial fibrillary acidic protein (GFAP) gave weakly-positive reactions. </span><strong><span class="fontstyle2">Conclusion: </span></strong><span class="fontstyle0">Based on the fndings, a pathological diagnosis of myoepithelioma was reached.</span> <br /><br /></p

Secretory Carcinoma of Minor Salivary Gland in Buccal Mucosa: A Case Report and Review of the Literature

Secretory carcinoma (SC) of the salivary gland was recently added to the fourth edition of the World Health Organization classification of head and neck tumors. Some salivary tumors, including acinic cell carcinoma, have been reclassified as SC. Most of these tumors are located on the parotid gland with very few cases reported in the minor salivary glands of the buccal mucosa. Herein, we present a case of SC of buccal mucosa, which appeared clinically as a benign lesion in a 54-year-old Japanese female patient. Histopathologically, the tumor cells presented with an eosinophilic cytoplasm with microcytic structure along with eosinophilic secretory material and hemosiderin deposit. Immunohistochemical staining revealed strongly positive staining for S100, vimentin, and mammaglobin and negative staining for DOG-1. The tumor was finally diagnosed as secretory carcinoma of the buccal mucosa. We present a review of the medical literature of SC arising from minor salivary glands. We found only 15 cases of SC of buccal mucosa out of 63 cases of SC in the minor salivary glands. They showed good prognoses and only one case of SC in the buccal mucosa exhibited local recurrence and lymph node metastases