Estudo da imunoexpressão dos transportadores de glicose 1 e 3 e do índice angiogênico em tumores odontológicos ceratocísticos isolados e associados à Síndrome de Gorlin

Abstract

The keratocystic odontogenic tumor (KOT) stands out among the other odontogenic lesions in view of the potentially aggressive biological behavior and its association in some cases, with the Gorlin syndrome. Some studies have suggested a more aggressive biological behavior for KOTs associated with Gorlin syndrome, compared to isolated KOTs, characterized by greater growth capacity and bone infiltration and higher tendency to recur. The present study aimed to evaluate, descriptively and comparatively, by means of immunohistochemistry, the expression of glucose transporter-1 (GLUT-1) and -3 (GLUT-3) and the angiogenic index (CD34) in isolated primary and recurrent KOTs and in KOTs associated with Gorlin syndrome. The sample was composed by 21 isolated KOTs (14 primary and 7 recurrent) and 14 KOTs associated with Gorlin syndrome. The expression of GLUTs was evaluated in the epithelial component of the lesions, establishing the percentage of immunopositive cells, according to the scores: score 0 (negative), score 1 (≤ 25% of positive cells), score 2 (26% - 50% of positive cells), score 3 (51% - 75% of positive cells), and score 4 (≥ 76% positive cells). For the angiogenic index, the microvessel count (MVC) technique was applied, quantifying the microvessels immunoreactive to anti-CD34 antibody. Regarding the median scores for immunopositivity for GLUT-1 and the angiogenic index, comparisons between groups were performed using the nonparametric Kruskal-Wallis test. For GLUT-3, the data obtained from the evaluation of epithelial expression of this protein were submitted to descriptive statistical analysis. Possible correlations between the scores of immunopositivity for GLUT-1 and angiogenic index in the lesions were evaluated using the Spearman correlation test. The level of significance was set at 5% (p <0.05). The analysis of epithelial GLUT-1 immunoreactivity revealed predominance of score 4 in isolated primary KOTs (n = 9, 64.3%) and in KOTs associated with Gorlin syndrome (n = 8; 57.1%). In isolated recurrent KOTs, it was identified a slightly higher frequency of cases with scores 4 (n = 3; 42.9%) and 2 (n = 2; 28.6%). The nonparametric Kruskal-Wallis test showed no statistically significant difference between groups (p = 0.406). Regarding the GLUT-3, all groups showed higher frequency of negative cases. The few KOTs positive for GLUT-3 were classified as score 1 (≤ 25% of positive cells), showing a low expression of this protein in the epithelial component. The mean number of microvessels was 63.80 in isolated primary KOTs, 61.11 in KOTs associated with the Gorlin syndrome, and 65.88 in isolated recurrent KOTs, without significant differences between groups (p = 0.965). The results of this study suggest that the differences in biological behavior of isolated KOTs and KOTs associated with Gorlin syndrome may not be related to the expression of GLUTs-1 and -3, or to the angiogenic index in the lesions. The high expression of GLUT-1 in KOTs suggests an important role for this protein in glucose uptake by the epithelial cells of these tumors.