Associação entre a expressão imuno-histoquímica de 8-OHdG e parâmetros clínico-patológicos em uma série de casos de queilites actínicas

Abstract

Actinic cheilitis (AC) is a potentially malignant disorder that can progress to lower lip squamous cell carcinoma (LLSCC). It is not yet well-established which factors may be associated with the probability of malignant transformation of this condition, but the exposure to ultraviolet radiation (UVR) represents the main risk factor for both AC and LLSCC. RUV causes oxidative damage to DNA, which leads to the formation of 8-hydroxy-2′deoxyguanosine (8-OHdG), This research aimed to evaluate the expression of 8-OHdG, in a series of cases of AC and to associate its expression with clinical-pathological parameters. The sample consisted of 57 cases of AC, analyzed morphologically and classified according to the histopathological gradation of epithelial dysplasia (WHO). Cases without dysplasia (7), with mild epithelial dysplasia (22), moderate epithelial dysplasia (17) and severe epithelial dysplasia (11) were observed. The analysis of the expression of 8-OHdG was performed in a semi-quantitative way by two calibrated examiners (Kappa = 0.79), assigning an immunoreactivity score for each evaluated case, which could vary from 0 to 6. The data were analyzed using Mann-Withney and KruskallWallis non-parametric tests, with a significance level of 5% (p <0.05). It was observed that most cases showed strong immunoreactivity (64.9%). There were no statistically significant differences between the expression of 8-OHdG and the clinical characteristics of QA, neither between the expression of 8-OHdG and the gradation of epithelial dysplasia present in the evaluated cases (p = 0.350). The strong immunoexpression of 8-OHdG in most cases of QA, regardless of the morphological changes present, suggests that oxidative damage to DNA is involved in the pathogenesis of this disorder.