Estudo comparativo da expressão de aldh1 em líquen plano oral, lesão liquenoide e leucoplasia em epitélio e no infiltrado inflamatório liquenoide

Abstract

Oral lichen planus (OLP) is a potentially malignant lesion and shares clinical and histopathological features with similar lesions. ALDH1 is a specific biomarker in the identification of stem cells, but its role in the stromal cells of the immune inflammatory infiltrate has not been elucidated yet. The aim of this study was to investigate the ALDH1 immunoexpression in epithelial and stromal cells from OLP and other lichenoid lesions. The study was approved by the Research Ethics Committee of the Universidade Federal de Minas Gerais (UFMG) under protocol nº 5.410.374, CAAE: 52763021.0.0000.5149. An search of the biopsy records of the Oral and Maxillofacial Pathology Laboratory at UFMG in a period of 10 years (2011 - 2021) was performed including the diagnosis of Oral Lichen Planus (OLP), Oral Lichenoid Lesion (OLL), Oral Leukoplakia (OLK) and Unspecific Inflammatory Process (UIP) – as control. Initially were obtained 633 cases. After inclusion and exclusion criteria a total of 64 cases were investigated for the ALDH1 immunohistochemical expression, 16 cases of each diagnose. ALDH1 was evaluated both in the epithelium and in the stromal cells. A percentage of ≤5% of ALDH1+ cells was considered positive in the epithelium. The evaluation of stromal cells was performed semi-quantitatively. The fields were classified into scores, according to the following criteria: 1 (0 to 10%); 2 (11 to 50%) and 3 (more than 51%). The mean value of the sum of the fields represented the final score. Statistical differences between groups were investigated and significance was established considering p < 0.05. Statistical analysis was performed using the software: SPSS – Statistical Package for the Social Science® (version 26.0, 2019, Chicago, IL, USA). The expression of ALDH1 in the epithelium was low in all groups with no difference between them, although most cases were found in the UIP samples. ALDH1+ cells in the lamina propria was higher for OLP (2.0) than others followed by OLK (1.3), OLL (1.2) and UIP (1.1) (p<0.05). The ALDH1 immunoexpression in the epithelium of lichenoid diseases did not prove to be contributory to show a malignant potential, but ALDH1 in stromal cells from OLP infiltrate might be involved in the complex immune regulation process associated with the pathogenesis of this disease