Imunossupressão das proteínas XPF e XRCC1 em carcinoma epidermoide de língua oral e lábio inferior

Abstract

The DNA repair system involves genes and proteins essential for the maintenance of genome integrity and consequent control of various cellular processes. Alterations in these genes and proteins are involved in the development of tumors, in their evolution and resistance to radio and chemotherapy treatments. The aim of this study was to analyze the immunoexpression of DNA repair proteins, XPF and XRCC1 in squamous cell carcinoma of the lower lip (SCCLL) and oral tongue (SCCOT) and investigate possible associations with the clinical and histopathological groups. For this purpose, 80 cases of SCCLL and SCCOT were selected and evaluated by grading systems proposed by Brandwein-Gensler et al. (2005) and Almangush et al. (2014). The immunohistochemical expression was performed semi-quantitatively, was used for statistical analysis the Chi-square tests, or when applicable, Fisher's exact test, to evaluate an association between the expressions of the proteins as clinical-pathological characteristics. A high nuclear expression of XPF was observed in 72.5% of cases of SCCOT and in 70% of cases of SCCLL. Regarding the XRCC1 immunoexpression in cases of SCCOT, high expression was observed in 60% of the cases and in the SCCLL 70% presented high nuclear expression, and no cytoplasmic expression was observed. Statistically significant associations were observed between immunoexpression of proteins with some clinical and histopathological parameters (p<0.05), however, there were no associations with the prognosis of the patients. The high expression of XPF and XRCC1 proteins in the cases of SCCOT and SCCLL suggest its importance in development and progression of these tumors. The results of this research indicate that immunoexpression of the studied proteins is not associated with a clinical and histopathological characteristics determinant for the biological tumor behavior.