IMMUNOHISTOCHEMICAL ANALYSIS OF AUTOPHAGY-RELATED PROTEINS IN PLEOMORPHIC ADENOMAS AND ADENOID CYSTIC CARCINOMAS OF SALI

Abstract

<h3>Objectives</h3> To evaluate the immunoexpression of autophagy-related proteins (Atg7, LC3A, p62, and phosphorylated mammalian target for rapamycin) in pleomorphic adenomas (PAs) and adenoid cystic carcinomas (ACCs) of the salivary glands. <h3>Study Design</h3> The percentages of cytoplasmic and nuclear staining for Atg7, LC3A, p62, and <i>P</i>-mTOR in neoplastic cells of 20 PAs and 14 ACCs were determined and correlated with histopathologic parameters. The results were analyzed statistically using the nonparametric Mann-Whitney test and Spearman correlation test. <h3>Results</h3> Cytoplasmic expression of autophagy-related proteins was observed in all cases of PA and ACC, with high median percentages of positivity for Atg7 and p62. Compared to ACCs, PAs exhibited higher cytoplasmic expression of Atg7, LC3A, and P-mTOR (<i>P</i> < .005), as well as higher nuclear expression of p62 (<i>P</i> < .0001). No significant differences in the immunoexpression of Atg7, LC3A, p62, and P-mTOR were observed according to histopathologic parameters of the tumors (<i>P</i> > .05). In PAs and ACCs, positive correlations were found for the immunoexpression of some autopaghy-related proteins (<i>P</i> < .05). <h3>Conclusions</h3> Autophagy may be involved in the pathogenesis of PA and ACC of the salivary glands. The upregulation of this intracellular degradation system and the reduced nuclear translocation of p62 could contribute to the aggressive biological behavior of ACC of salivary glands.