Immunohistochemical study of P53 protein expression in the development of squamous cell carcinoma of the oral mucosa

Relevance. Studies on the development of squamous cell carcinoma of the oral mucosa are of paramount importance due to the widespread of the disease and its aggressive course. When histological examination of the development of squamous cell carcinoma of the oral mucosa is not always possible to determine the first signs of malignancy. Squamous cell carcinoma can develop from epithelial hyperplasia and epithelial dysplasia of varying severity. In addition to histological research methods, immunohistochemical method is widely used for tumor diseases, in which the Ki-67 protein is used, with which the proliferation of epithelial cells can be determined, as well as the P53 protein encoding the TP53 gene, which is a suppressor of tumor growth. It is activated only in the presence of damage to the cell genome. The aim was to evaluate the expression of Ki-67 and P53 proteins in the development of dysplasia and squamous cell carcinoma of the oral mucosa. Materials and Methods. Four groups were identified for the study: group 1-16 patients (34.7%) diagnosed with epithelial hyperplasia, group 2-8 patients (17.3%) diagnosed with low-grade epithelial dysplasia, group 3-9 (19.5%) with a diagnosis of “high-grade epithelial dysplasia”, group 4-13 (28.2%) with a diagnosis of “squamous cell carcinoma”. Mouse monoclonal antibodies to Ki-67 (clone MM1, Diagnostic Biosystems, USA) was used to determine cell proliferation. P53 expression was determined using mouse monoclonal antibodies to the P53 protein (Clone D 07, Novocastra, UK). Monoclonal rabbit antibodies P53 (Clone Y5 Epitomics, USA) were used to study only the “mutant type” of the P53 protein. Results and Discussion. The expression of Ki-67 and P53 proteins were observed in all groups. However, the minimum number of immunopositive cells in the study of P53 (Clone D 07) and P53 (Clone Y5) was observed in the epithelial hyperplasia group, and the maximum in the squamous cell carcinoma group. The increase in the number of stained cells significantly increased as the degree of epithelial dysplasia increased from epithelial hyperplasia and low grade epithelial dysplasia to high grade epithelial dysplasia, etc. Conclusion. Thus, the detection of the expression of the P53 protein (Clone Y5) in the epithelium indicates the presence of changes in the genetic apparatus and metabolism of cells, which can be used in the early diagnosis of squamous cell carcinoma of the oral mucosa.