RESUMO
Background: The extracellular matrix (ECM) is a dynamic tissue that provides nutrition and support to overlying epithelium. During tumorigenesis, the tumor microenvironment (TME) dysregulates the ECM. This is reflected by morphological changes seen in collagen and elastic fibers and is thought to facilitate metastasis. Aim: To study the degradation of elastic fibers in different grades of oral squamous cell carcinoma (OSCC) and in oral epithelial dysplasia (OED) using histochemistry and to correlate it to the TNM stage of OSCC. Materials and Methods: Tumor cores from 38 cases of OSCC (well-differentiated[15], moderately differentiated[14], and poorly differentiated[9]) and 15 incisional biopsies of OED were analyzed. Hematoxylin-eosin and Verhoeff's–Van Gieson (VVG) stains were used. The stained sections were assessed for morphological changes in elastic fibers. Statistical Analysis: Data were analyzed using Statistical Package for Social Sciences (SPSS) version 22 software. Fisher's exact, Kruskal–Wallis, one-way ANOVA, and Turkey post hoc tests were used to establish significance (P ? 0.05). Spearman's correlation test was used to correlate elastin fiber degradation with TNM stage of OSCC. Results: All grades of OSCC showed absence of elastic fibers around the tumor islands. Elastic fiber degradation (fragmented and clumped type fibers) increased proportionately with the grade and TNM stage of OSCC. In OED, A significant reduction in the amount of elastic fibers with increasing grade was noted. Conclusion: A positive correlation was noted between elastin degradation and grade and stage of OSCC. Therefore, it may be implicated in tumor progression of OSCC.
RESUMO
Introduction: Ameloblastoma is a benign epithelial odontogenic neoplasm that constitutes approximately 1% of all oral tumors and about 9 to 11% of all odontogenic tumors. They are slow-growing, locally invasive, and demonstrate a potential for metastasis and malignant transformation. The molecular pathogenesis of ameloblastoma is attributed to aberrant activity of the signal transduction pathways relating to developmental stages of odontogenesis including the mitogen-activated protein kinase (MAPK) pathway. The BRAF V600E mutation was identified as the most frequently mutated gene in this neoplasm. Studies have shown that use of BRAF inhibitors in patients diagnosed with ameloblastomas led to a significant reduction in tumor volume. Aims: To detect the expression of BRAF V600E mutation in ameloblastomas in an Indian population using immunohistochemistry. To compare the difference in the occurrence of the BRAF V600E mutation between mandibular and maxillary cases. Materials and Methods: Thirty-three formalin-fixed paraffin-embedded tissues of histopathologically proven cases of ameloblastoma were assessed for the BRAF V600E mutation by immunohistochemistry using the BRAF V600E monoclonal antibody. Patient data such as age, sex, anatomical site, recurrence were documented. Statistical Analysis: The statistical analysis was performed using the Pearson Chi-square test and Student's t-test. Results: The present study revealed a high expression of the BRAFV600E mutation in mandibular cases of ameloblastoma among Indians irrespective of the age, sex, site, recurrence or histological pattern. Conclusions: The identification of this driver mutation opens the possibility of an adjuvant therapeutic modality to reduce the significant facial disfigurement and morbidity following surgical management.