title: DNA methyltransferase immunohistochemical expression in odontogenic tumours.
abstract: BACKGROUND
  Odontogenic tumours are a heterogeneous group of lesions formed from tissues that give rise to the tooth. DNA methylation, a covalent addition of a methyl group to the 5-carbon position of a cytosine nucleotide, is considered an important regulator of gene expression. The addition of the methyl radical is catalysed by DNA methyltransferases (DNMTs). Although some epigenetic studies have been conducted in odontogenic tumours, a study with the three types of DNMTs in several different members of this group is missing. This study analyses the expression of DNMTs in odontogenic tumours.
  
  
  METHODS
  Formalin-fixed and paraffin-embedded tissue samples of 20 ameloblastomas, 10 calcifying cystic odontogenic tumours, 10 calcifying epithelial tumours, 10 adenomatoid odontogenic tumours, 10 keratocystic odontogenic tumours, five ameloblastic fibromas, two ameloblastic fibro-odontomas, four central odontogenic fibromas, seven peripheral odontogenic fibromas and 10 odontogenic myxomas were included. Immunohistochemical expression of DNMT1, 3A and 3B was assessed using a semi-quantitative analysis, and also a correlation with p21, p27 and E-cadherin immunoexpression was made.
  
  
  RESULTS
  DNMT1, 3A and 3B were expressed in the nucleus and/or cytoplasm of all odontogenic tumours. DNMT1 expression was directly correlated with p27 expression in ameloblastomas.
  
  
  CONCLUSIONS
  The high expression of DNMTs in odontogenic tumour cells suggests methylation as an important mechanism for this group of tumours.
authors: Department of Oral Pathology, School of Dentistry, University of São Paulo, São Paulo, Brazil.
authors: Douglas Magno
authors: DM
authors: Guimarães
authors: Daniella Moraes
authors: DM
authors: Antunes
authors: Carina Magalhães Esteves
authors: CM
authors: Duarte
authors: Leonardo Borges
authors: LB
authors: Ferro
authors: Fabio Daumas
authors: FD
authors: Nunes
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000564:Ameloblastoma / Q000737:chemistry / Q000201:enzymology; D015820:Cadherins / Q000032:analysis; D002467:Cell Nucleus / Q000737:chemistry / Q000201:enzymology; D002648:Child; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000032:analysis; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000032:analysis; D003593:Cytoplasm / Q000737:chemistry / Q000201:enzymology; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000032:analysis*; D000090205:DNA Methyltransferase 3A; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009808:Odontogenic Tumors / Q000737:chemistry / Q000201:enzymology*; D055815:Young Adult; D000097584:DNA Methyltransferase 3B
chemical_list: D015820:Cadherins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D050760:Cyclin-Dependent Kinase Inhibitor p27; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; D000097584:DNA Methyltransferase 3B; C493956:CDKN1A protein, human; C000717967:DNMT3A protein, human; C000619380:DNMT1 protein, human
keywords: DNA methyltransferases; epigenetics; methylation; odontogenic tumours