Imunoexpressão das proteínas APE1, XRCC1, p53 e Ki67 em carcinoma de células escamosas de língua oral

Abstract

Oral squamous cells carcinoma (OSCC) results from processes of decontrol of cellular events caused by mutations due genotoxic agents, which may lead, among other factors, to loss of control of the cellular proliferation process, being considered as one of the precursors of oral cancer. Searching biomarkers for OSCC is the target of several studies, among the markers it is highlighted the DNA repair proteins, such as XRCC1 and APE1, and cell cycle proteins, such as p53 and Ki67. Thus, the aim of this study was to analyze the immunohistochemical expression of APE1, XRCC1 and the proteins involved in the cell cycle, p53 and ki67, associating them with clinical and histopathological prognostic parameters in oral tongue squamous cell carcinoma (OTSCC), in order to contribute to the better understanding of the participation of these proteins in the development of this neoplasia. The immunohistochemical expression of APE1 and XRCC1 was evaluated semiquantitatively and the expression of p53 and ki67 quantitatively, in 58 cases of OTSCC. Clinical data were collected from the medical records of each patient and the histopathological grading of Brandwein-Gensler was carried out for each case. For the statistical analysis, Chi-square and Fisher's exact test were performed, and significance was set at p <0.05. The majority of cases showed high immunoexpression of APE1 (n = 36; 62.1%), as well as of XRCC1 (n = 38; 65.5%). In relation to the Ki67 and p53 proteins, there was an equal distribution when the cases were categorized into low and high expression (n = 29, 50%). XRCC1 immunoexpression was significantly higher in cases of early stage lesions I and II (n = 23; 62.2%) compared to advanced stages III and IV (n = 16, 80%, p = 0.05). The Immunoexpression of p53 was significantly higher in cases of advanced lesion (n = 19; 65.5%) and low in early stages (n = 17, 60.7%, p = 0.047). None of the studied proteins showed association with each other, nor with the other clinical parameters and histopathological grading. Despite the significant association of the highest XRCC1 immunoexpression with better clinical staging and of p53 with the worst clinical staging, these results were not supported when the patients' outcome were analyzed. The results of this study indicate that XRCC1 and APE1 participate in the process of carcinogenesis of OTSCC, but the immunohistochemical expression of these proteins and also p53 and Ki67 did not show any association with prognostic parameters.