Expressão imuno-histoquímica de proteínas ING em desordens potencialmente malignas

Abstract

Potentially malignant disorders (PMD) are lesions that can affect the oral cavity and present a potential for malignant transformation. Molecular biomarkers have been studied to help predict the risk of malignant transformation of these lesions. Among them, the ING (inhibitor of growth) proteins (1-5) are highlighted. The objective of this study is to evaluate the expression of ING-1 and ING-2 proteins in lesions diagnosed as hyperkeratosis and ED (mild, moderate and severe), and to correlate the expression pattern observed with the degree of epithelial dysplasia. This is a cross-sectional, retrospective, semi-quantitative and comparative study. The sample consisted of 60 specimens of hyperkeratosis and epithelial dysplasia (ED), which were morphologically evaluated and reclassified according to the binary classification system of ED proposed by Kujan et al. (2006). The immunoexpression for ING-1 and ING-2 in the studied lesions was evaluated semi-quantitatively from the assignment of scores ranging from 0 to 4, according to the percentage of epithelial cells positive for those markers. For the statistical analysis, the Mann-Whitney and Spearman tests (p ≤ 0.05) were performed. Of the 60 cases analyzed, 37 (61.7%) presented as low-risk lesions and 23 (38.3%) as highrisk lesions. For both ING-1 and ING-2, 93.3% of the dysplastic lesions studied presented cytoplasmic and nuclear marking on epithelial cells, with predominance of positivity in the basal and suprabasal layers. Regarding the immunohistochemical marking scores, there was a predominance of cases with high expression (score 4) for both markers. However, when comparing these scores (nuclear, cytoplasmic and general) with the histological gradation of ED, for both ING-1 and ING-2, no statistically significant difference was observed. Thus, the results of the present study suggest that immunoexpression of ING-1 and ING-2 is not related to the degree of oral ED. However, the high expression observed in these lesions suggests that these proteins would be involved in the oral carcinogenesis process.