Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Original Paper Pathobiology 2009;76:136–140 DOI: 10.1159/000209391 Immunolocalization of DNMT1 and DNMT3a in Salivary Gland Neoplasms Carolina Cavaliéri Gomes b Carla da Silveira e Oliveira b Luiz Gustavo Garcia Santos Pimenta a Luiz De Marco c Ricardo Santiago Gomez b a School of Dentistry, Pontifícia Universidade Católica de Minas Gerais, and Departments of b Oral Surgery and Pathology and c Pharmacology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil to demonstrate a clear correlation between DNMT1 and DNMT3a immunoexpression and salivary gland neoplasms development. Copyright © 2009 S. Karger AG, Basel Introduction Salivary gland neoplasms are relatively uncommon le- sions representing 0.3–1.5% of all biopsies processed in oral pathology laboratories, predominantly affecting ma- jor salivary glands [1]. Minor glands account for 9–23% of all salivary gland neoplasms [1]. The intraoral site most commonly affected by benign and malignant neoplasms is the palate. Pleomorphic adenoma (PA) is the most com- mon benign salivary gland neoplasm, while mucoepider- moid carcinoma (MEC) is the most common malignant one, followed by adenoid cystic carcinoma (ACC) and polymorphous low-grade adenocarcinoma (PLGA) [1]. Recent studies have demonstrated that the develop- ment and progression of human malignancies are associ- ated with accumulation of alterations in proto-oncogenes and tumor suppressor genes [2, 3] . Epigenetic alterations such as DNA methylation are important for human car- cinogenesis, but its role in salivary gland neoplasias has not been well established. Key Words DNA methyltransferase  Methyltransferase  Salivary gland neoplasms  Methylation  Epigenetics Abstract Objective: Salivary gland neoplasms pathogenesis has not been well established. DNA methylation occurs when meth- yl groups are added to cytosine nucleotides in specific areas of the gene by the enzyme DNA methyltransferase (DNMT). This chemical modification can alter gene expression with- out altering DNA sequence. While DNMT3a is mostly in- volved in de novo methylation, DNMT1 acts as a main- tenance methyltransferase. We aimed to investigate the immunoexpression of DNMT3a and DNMT1 in minor salivary gland neoplasms, comparing it with normal tissue. Material: Forty-four formalin-fixed and paraffin-embedded samples of pleomorphic adenoma, adenoid cystic carcinoma, muco- epidermoid carcinoma and polymorphous low-grade ade- nocarcinoma were included in the study. The DNMT1 and DNMT3a proteins were identified by using a highly sensitive polymer-based system. Results: Positive nuclear and cyto- plasmic labeling for DNMT1 was observed in all samples, in- cluding the controls. Positive nuclear labeling for DNMT3a was found only in few neoplasms: 1 pleomorphic adenoma (9.0%), 2 adenoid cystic carcinoma (16.6%) and 1 mucoepi- dermoid (9.0%) cases. Conclusion: Our results were not able Received: September 17, 2008 Accepted after revision: November 18, 2008 Prof. Ricardo Santiago Gomez Departamento de Patologia e Cirurgia, Faculdade de Odontologia Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627 Belo Horizonte, MG 31270-901 (Brazil) Tel. +55 31 3409 2477, Fax +55 31 3409 2430, E-Mail rsgomez@ufmg.br © 2009 S. Karger AG, Basel 1015–2008/09/0763–0136$26.00/0 Accessible online at: www.karger.com/pat