Pleomorphic adenoma of oral minor salivary glands: An investigation of its neoplastic potential based on apoptosis, mucosecretory activity and cellular proliferation

• Published in: Archives of oral biology Vol. 59; no. 6; pp. 578 - 585
• Main Authors: Ferreira, Jean Carlos Barbosa, Morais, Marília Oliveira, Elias, Marcela Ramos Abrahão, Batista, Aline Carvalho, Leles, Claudio Rodriguês, Mendonça, Elismauro Francisco
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.06.2014
• Subjects: Adenoma, Pleomorphic - metabolism; Adenoma, Pleomorphic - pathology; Adult; Advanced Basic Science; Aged; Apoptosis; bcl-2-Associated X Protein - metabolism; Biological behaviour; Biomarkers, Tumor - metabolism; Biopsy; Case-Control Studies; Cell Proliferation; Child; Dentistry; Female; Humans; Immunoenzyme Techniques; Ki-67 Antigen - metabolism; Male; Middle Aged; Mucin-1 - metabolism; Mucosecretory activity; Pleomorphic adenoma; Proto-Oncogene Proteins c-bcl-2 - metabolism; Salivary Gland Neoplasms - metabolism; Salivary Gland Neoplasms - pathology; Salivary Glands, Minor - pathology; Tumor Suppressor Protein p53 - metabolism; Cell proliferation; Pleomorphic adenoma; Mucosecretory activity; Apoptosis; Biological behaviour
• ISSN: 0003-9969; 1879-1506
• DOI: 10.1016/j.archoralbio.2014.03.002

Abstract Objective The aim of this study was to investigate the neoplastic potential of the PA of minor oral salivary glands measured by apoptosis (Bcl-2, Bax and p53), mucosecretory activity (MUC1), and cellular proliferation (Ki-67). Design Thirty-one cases of PA of the oral cavity and four controls (C) taken from normal oral minor salivary glands were analyzed using the immunohistochemistry technique. The proteins were detected utilizing a semi-quantitative method (scores) as follows: (−) negative ≤5%, (+) low 6–25%, (++) moderate 26–50% and (+++) high >50% of positive tumour cells. The apoptotic indices were evaluated by the ratio Bcl-2/Bax. Non-parametric comparison and correlation tests were used for analysis. Results The data showed high staining of anti-apoptotic protein Bcl-2 in both groups (PA = 57.9%; C = 67.7%) and a significantly lower expression of pro-apoptotic protein Bax (PA = 22.7%; C = 97.7%) and MUC1 (PA = 14%; C = 82.3%) in PA than in C ( p < 0.001). On the other hand, a similar expression of Ki-67 and p53 proteins (≤5%) was seen in both PA and C. In PA, only 2/31 cases showed the ratio Bcl-2/Bax < 1.There was no difference in cellular expression with regard to clinical variables or clinical outcome ( p > 0.05). Conclusion The neoplastic potential of PA could be associated with an imbalance in apoptotic processes and a lower index of cellular proliferation. Mucosecretory activity does not play a significant role in primary PA.